Feasibility study using a Ni-Ti stent and electronic portal imaging to localize the prostate during radiotherapy.

PubMed

Carl, Jesper; Lund, Bente; Larsen, Erik Hoejkjaer; Nielsen, Jane

2006-02-01

A new method for localization of the prostate during external beam radiotherapy is presented. The method is based on insertion of a thermo-expandable Ni-Ti stent. The stent is originally developed for treatment of bladder outlet obstruction caused by benign hyperplasia. The radiological properties of the stent are used for precise prostate localization during treatment using electronic portal images. Patients referred for intended curative radiotherapy and having a length of their prostatic urethra in the range from 25 to 65 mm were included. Pairs of isocentric orthogonal portal images were used to determine the 3D position at eight different treatment sessions for each patient. Fourteen patients were enrolled in the study. The data obtained demonstrated that the stent position was representative of the prostate location. The stent may also improve delineation of the prostate GTV, and prevent obstruction of bladder outlet during treatment. Precision in localization of the stent was less than 1 mm. Random errors in stent position were left-right 1.6 mm, cranial-caudal 2.2 mm and anterior-posterior 3.2 mm. In four of 14 patients a dislocation of the stent to the bladder occurred. Dislocation only occurred in patients with length of prostatic urethra less than 40 mm. A new method for radiological high precision localization of the prostate during radiotherapy is presented. The method is based on insertion of a standard Ni-Ti thermo-expandable stent, designed for treatment of benign prostate hyperplasia.

Bladder Preservation for Localized Muscle-Invasive Bladder Cancer: The Survival Impact of Local Utilization Rates of Definitive Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozak, Kevin R.; Hamidi, Maryam; Manning, Matthew

2012-06-01

Purpose: This study examines the management and outcomes of muscle-invasive bladder cancer in the United States. Methods and Materials: Patients with muscle-invasive bladder cancer diagnosed between 1988 and 2006 were identified in the Surveillance, Epidemiology, and End Results (SEER) database. Patients were classified according to three mutually exclusive treatment categories based on the primary initial treatment: no local management, radiotherapy, or surgery. Overall survival was assessed with Kaplan-Meier analysis and Cox models based on multiple factors including treatment utilization patterns. Results: The study population consisted of 26,851 patients. Age, sex, race, tumor grade, histology, and geographic location were associated withmore » differences in treatment (all p < 0.01). Patients receiving definitive radiotherapy tended to be older and have less differentiated tumors than patients undergoing surgery (RT, median age 78 years old and 90.6% grade 3/4 tumors; surgery, median age 71 years old and 77.1% grade 3/4 tumors). No large shifts in treatment were seen over time, with most patients managed with surgical resection (86.3% for overall study population). Significant survival differences were observed according to initial treatment: median survival, 14 months with no definitive local treatment; 17 months with radiotherapy; and 43 months for surgery. On multivariate analysis, differences in local utilization rates of definitive radiotherapy did not demonstrate a significant effect on overall survival (hazard ratio, 1.002; 95% confidence interval, 0.999-1.005). Conclusions: Multiple factors influence the initial treatment strategy for muscle-invasive bladder cancer, but definitive radiotherapy continues to be used infrequently. Although patients who undergo surgery fare better, a multivariable model that accounted for patient and tumor characteristics found no survival detriment to the utilization of definitive radiotherapy. These results support continued research into bladder preservation strategies and suggest that definitive radiotherapy represents a viable initial treatment strategy for those who wish to attempt to preserve their native bladder.« less

Remote acute demyelination after focal proton radiation therapy for optic nerve meningioma.

PubMed

Redjal, Navid; Agarwalla, Pankaj K; Dietrich, Jorg; Dinevski, Nikolaj; Stemmer-Rachamimov, Anat; Nahed, Brian V; Loeffler, Jay S

2015-08-01

We present a unique patient with delayed onset, acute demyelination that occurred distant to the effective field of radiation after proton beam radiotherapy for an optic nerve sheath meningioma. The use of stereotactic radiotherapy as an effective treatment modality for some brain tumors is increasing, given technological advances which allow for improved targeting precision. Proton beam radiotherapy improves the precision further by reducing unnecessary radiation to surrounding tissues. A 42-year-old woman was diagnosed with an optic nerve sheath meningioma after initially presenting with vision loss. After biopsy of the lesion to establish diagnosis, the patient underwent stereotactic proton beam radiotherapy to a small area localized to the tumor. Subsequently, the patient developed a large enhancing mass-like lesion with edema in a region outside of the effective radiation field in the ipsilateral frontal lobe. Given imaging features suggestive of possible primary malignant brain tumor, biopsy of this new lesion was performed and revealed an acute demyelinating process. This patient illustrates the importance of considering delayed onset acute demyelination in the differential diagnosis of enhancing lesions in patients previously treated with radiation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Intraoperative radiotherapy. Literature updating with an overview of results presented at the 6th International Symposium of Intraoperative Radiation Therapy.

PubMed

Calvo, F A; Santos, M; Azinovic, I

1998-01-01

Intraoperative radiotherapy is a technique that can be integrated into multidisciplinary treatment strategies in oncology. A radiation boost delivered with high energy electron beams can intensify locoregional antitumor therapy in patients undergoing cancer surgery. Intraoperative radiotherapy can increase the therapeutic index of the conventional combination of surgery and radiotherapy by improving the precision of radiation dose location, while decreasing the normal tissue damage in mobile structures and enhancing the biological effect of radiation when combined with surgical debulking. Intraoperative radiotherapy has been extensively investigated in clinical oncology in the last 15 years. Commercially available linear accelerators require minimal changes to be suitable for intraoperative radiotherapy. Its successful implementation in clinical protocols depends on the support given by the single institutions and on a clinical research-oriented mentality. Tumors where intraoperative radiotherapy as a treatment component has shown promising rates of local control include locally advanced rectal, gastric and gynecologic cancer, bone and soft tissue sarcoma. Intraoperative radiotherapy can be applied to brain tumors, head and neck cancer, NSCLC and pancreatic carcinoma.

[Polymer Gel Dosimeter].

PubMed

Hayashi, Shin-Ichiro

2017-01-01

With rapid advances being made in radiotherapy treatment, three-dimensional (3D) dose measurement techniques of great precision are required more than ever before. It is expected that 3D polymer gel dosimeters will satisfy clinical needs for an effective detector that can measure the complex 3D dose distributions. Polymer gel dosimeters are devices that utilize the radiation-induced polymerization reactions of vinyl monomers in a gel to store information about radiation dose. The 3D absorbed dose distribution can be deduced from the resulting polymer distribution using several imaging modalities, such as MRI, X-ray and optical CTs. In this article, the fundamental characteristics of polymer gel dosimeter are reviewed and some challenging keys are also suggested for the widely spread in clinical use.

The role of intraoperative radiotherapy in solid tumors.

PubMed

Skandarajah, A R; Lynch, A C; Mackay, J R; Ngan, S; Heriot, A G

2009-03-01

Combined multimodality therapy is becoming standard treatment for many solid tumors, but the role of intraoperative radiotherapy in the management of solid tumors remains uncertain. The aim is to review the indication, application, and outcomes of intraoperative radiotherapy in the management of nongynecological solid tumors. A literature search was performed using Medline, Embase, Ovid, and Cochrane database for studies between 1965 and 2008 assessing intraoperative radiotherapy, using the keywords "intraoperative radiotherapy," "colorectal cancer," "breast cancer," "gastric cancer," "pancreatic cancer," "soft tissue tumor," and "surgery." Only publications in English with available abstracts and regarding adult humans were included, and the evidence was critically evaluated. Our search retrieved 864 publications. After exclusion of nonclinical papers, duplicated papers and exclusion of brachytherapy papers, 77 papers were suitable to assess the current role of intraoperative radiotherapy. The clinical application and evidence base of intraoperative radiotherapy for each cancer is presented. Current studies in all common cancers show an additional benefit in local recurrence rates when intraoperative radiotherapy is included in the multimodal treatment. However, intraoperative radiotherapy may not improve overall survival and has significant morbidity depending on the site of the tumor. Intraoperative radiotherapy does have a role in the multidisciplinary management of solid tumors, but further studies are required to more precisely determine the extent of benefit.

Genomic and Histopathological Tissue Biomarkers That Predict Radiotherapy Response in Localised Prostate Cancer

PubMed Central

Wilkins, Anna; Dearnaley, David; Somaiah, Navita

2015-01-01

Localised prostate cancer, in particular, intermediate risk disease, has varied survival outcomes that cannot be predicted accurately using current clinical risk factors. External beam radiotherapy (EBRT) is one of the standard curative treatment options for localised disease and its efficacy is related to wide ranging aspects of tumour biology. Histopathological techniques including immunohistochemistry and a variety of genomic assays have been used to identify biomarkers of tumour proliferation, cell cycle checkpoints, hypoxia, DNA repair, apoptosis, and androgen synthesis, which predict response to radiotherapy. Global measures of genomic instability also show exciting capacity to predict survival outcomes following EBRT. There is also an urgent clinical need for biomarkers to predict the radiotherapy fraction sensitivity of different prostate tumours and preclinical studies point to possible candidates. Finally, the increased resolution of next generation sequencing (NGS) is likely to enable yet more precise molecular predictions of radiotherapy response and fraction sensitivity. PMID:26504789

[Bladder-conserving treatment for bladder cancer: potential of and developments in radiotherapy].

PubMed

Hulshof, Maarten C C M; Pieters, Bradley R; Koning, Caro C E

2013-01-01

The standard treatment for muscle-invasive bladder cancer is surgical removal of the bladder and construction of a neobladder. Recently, important improvements have been made in the potential for bladder-conserving treatment using radiotherapy. External beam radiotherapy has undergone technological improvements, as a result of which it is possible to radiate the tumour more precisely while decreasing radiation to healthy tissue. Radiochemotherapy improves local recurrence-free and overall survival compared with radiotherapy alone. The results of this combined treatment are comparable with those of surgery. Additionally, Dutch radiotherapy departments have collected data in a national database of 1040 selected patients with confined bladder cancer. These patients were treated with external beam radiation, limited surgery and brachytherapy. The 5-year local recurrence-free survival was 75%. Bladder conserving treatment options for muscle-invasive bladder cancer should be discussed during the multidisciplinary meeting.

Utility approach to decision-making in extended T1 and limited T2 glottic carcinoma.

PubMed

van Loon, Yda; Stiggelbout, Anne M; Hakkesteegt, Marieke M; Langeveld, Ton P M; de Jong, Rob J Baatenburg; Sjögren, Elisabeth V

2017-04-01

It is still undecided if endoscopic laser surgery or radiotherapy is the preferable treatment in extended T1 and limited T2 glottic tumors. Health utilities assessed from patients can aid in decision-making. Patients treated for extended T1 or limited T2 glottic carcinoma by laser surgery (n = 12) or radiotherapy (n = 14) assigned health utilities using a visual analog scale (VAS), time tradeoff (TTO) technique and scored their voice handicap using the Voice Handicap Index (VHI). VAS and TTO scores were slightly lower for the laser group compared to the radiotherapy group, however, not significantly so. The VHI showed a correlation with the VAS score, which was very low in both groups and can be considered (near) normal. Patients show no clear preference for the outcomes of laser surgery or radiotherapy from a quality of life (QOL) or voice handicap point of view. These data can now be incorporated into decision-making models. © 2017 Wiley Periodicals, Inc. Head Neck, 2017 © 2016 Wiley Periodicals, Inc. Head Neck 39: 779-785, 2017. © 2017 Wiley Periodicals, Inc.

Theranostics of prostate cancer: from molecular imaging to precision molecular radiotherapy targeting the prostate specific membrane antigen.

PubMed

Kulkarni, Harshad R; Singh, Aviral; Langbein, Thomas; Schuchardt, Christiane; Mueller, Dirk; Zhang, Jingjing; Lehmann, Coline; Baum, Richard P

2018-06-01

Alterations at the molecular level are a hallmark of cancer. Prostate cancer is associated with the overexpression of prostate-specific membrane antigen (PSMA) in a majority of cases, predominantly in advanced tumors, increasing with the grade or Gleason's score. PSMA can be selectively targeted using radiolabeled PSMA ligands. These small molecules binding the PSMA can be radiolabeled with γ-emitters like 99m Tc and 111 In or positron emitters like 68 Ga and 18 F for diagnosis as well as with their theranostic pairs such as 177 Lu (β-emitter) or 225 Ac (α-emitter) for therapy. This review summarizes the theranostic role of PSMA ligands for molecular imaging and targeted molecular radiotherapy, moving towards precision oncology.

COTS Silicon diodes as radiation detectors in proton and heavy charged particle radiotherapy 1.

PubMed

Kaiser, Franz-Joachim; Bassler, Niels; Jäkel, Oliver

2010-08-01

Modern radiotherapy facilities for cancer treatment such as the Heavy Ion Therapy Center (HIT) in Heidelberg, Germany, allow for sub-millimeter precision in dose deposition. For measurement of such dose distributions and characterization of the particle beams, detectors with high spatial resolution are necessary. Here, a detector based on the commercially available COTS photodiode (BPW-34) is presented. When applied in hadronic beams of protons and carbon ions, the detector reproduces dose distribution well, but its response decreases rapidly by radiation damage. However, for MeV photon beams, the detector exhibits a similar behavior as found in diode detectors usually applied in radiotherapy.

Challenges and opportunities in patient-specific, motion-managed and PET/CT-guided radiation therapy of lung cancer: review and perspective

PubMed Central

2012-01-01

The increasing interest in combined positron emission tomography (PET) and computed tomography (CT) to guide lung cancer radiation therapy planning has been well documented. Motion management strategies during treatment simulation PET/CT imaging and treatment delivery have been proposed to improve the precision and accuracy of radiotherapy. In light of these research advances, why has translation of motion-managed PET/CT to clinical radiotherapy been slow and infrequent? Solutions to this problem are as complex as they are numerous, driven by large inter-patient variability in tumor motion trajectories across a highly heterogeneous population. Such variation dictates a comprehensive and patient-specific incorporation of motion management strategies into PET/CT-guided radiotherapy rather than a one-size-fits-all tactic. This review summarizes challenges and opportunities for clinical translation of advances in PET/CT-guided radiotherapy, as well as in respiratory motion-managed radiotherapy of lung cancer. These two concepts are then integrated into proposed patient-specific workflows that span classification schemes, PET/CT image formation, treatment planning, and adaptive image-guided radiotherapy delivery techniques. PMID:23369522

Estimating radiotherapy demands in South East Asia countries in 2025 and 2035 using evidence-based optimal radiotherapy fractions.

PubMed

Yahya, Noorazrul; Roslan, Nurhaziqah

2018-01-08

As about 50% of cancer patients may require radiotherapy, the demand of radiotherapy as the main treatment to treat cancer is likely to rise due to rising cancer incidence. This study aims to quantify the radiotherapy demand in countries in Southeast Asia (SEA) in 2025 and 2035 using evidence-based optimal radiotherapy fractions. SEA country-specific cancer incidence by tumor site for 2015, 2025 and 2035 was extracted from the GLOBOCAN database. We utilized the optimal radiotherapy utilization rate model by Wong et al. (2016) to calculate the optimal number of fractions for all tumor sites in each SEA country. The available machines (LINAC & Co-60) were extracted from the IAEA's Directory of Radiotherapy Centres (DIRAC) from which the number of available fractions was calculated. The incidence of cancers in SEA countries are expected to be 1.1 mil cases (2025) and 1.4 mil (2035) compared to 0.9 mil (2015). The number of radiotherapy fractions needed in 2025 and 2035 are 11.1 and 14.1 mil, respectively, compared to 7.6 mil in 2015. In 2015, the radiotherapy fulfillment rate (RFR; required fractions/available fractions) varied between countries with Brunei, Singapore and Malaysia are highest (RFR > 1.0 - available fractions > required fractions), whereas Cambodia, Indonesia, Laos, Myanmar, Philippines, Timor-Leste and Vietnam have RFR < 0.5. RFR is correlated to GDP per capita (ρ = 0.73, P = 0.01). To allow RFR ≥1 in 2025 and 2035, another 866 and 1177 machines are required, respectively. The number are lower if longer running hours are implemented. With the optimal number of radiotherapy fractions, estimation for number of machines required can be obtained which will guide acquisition of machines in SEA countries. RFR is low with access varied based on the economic status. © 2018 John Wiley & Sons Australia, Ltd.

Renal-Clearable Ultrasmall Coordination Polymer Nanodots for Chelator-Free 64Cu-Labeling and Imaging-Guided Enhanced Radiotherapy of Cancer.

PubMed

Shen, Sida; Jiang, Dawei; Cheng, Liang; Chao, Yu; Nie, Kaiqi; Dong, Ziliang; Kutyreff, Christopher J; Engle, Jonathan W; Huang, Peng; Cai, Weibo; Liu, Zhuang

2017-09-26

Developing tumor-homing nanoparticles with integrated diagnostic and therapeutic functions, and meanwhile could be rapidly excreted from the body, would be of great interest to realize imaging-guided precision treatment of cancer. In this study, an ultrasmall coordination polymer nanodot (CPN) based on the coordination between tungsten ions (W VI ) and gallic acid (W-GA) was developed via a simple method. After polyethylene glycol (PEG) modification, PEGylated W-GA (W-GA-PEG) CPNs with an ultrasmall hydrodynamic diameter of 5 nm were rather stable in various physiological solutions. Without the need of chelator molecules, W-GA-PEG CPNs could be efficiently labeled with radioisotope 64 Cu 2+ , enabling positron emission tomography (PET) imaging, which reveals efficient tumor accumulation and rapid renal clearance of W-GA-PEG CPNs upon intravenous injection. Utilizing the radio-sensitizing function of tungsten with strong X-ray absorption, such W-GA-PEG CPNs were able to greatly enhance the efficacy of cancer radiotherapy in inhibiting the tumor growth. With fast clearance and little long-term body retention, those W-GA-PEG CPNs exhibited no appreciable in vivo toxicity. This study presents a type of CPNs with excellent imaging and therapeutic abilities as well as rapid renal clearance behavior, promising for further clinic translation.

Potential risk of alpha-glucosidase inhibitor administration in prostate cancer external radiotherapy by exceptional rectal gas production: a case report.

PubMed

Nishimura, Takuya; Yamazaki, Hideya; Iwama, Kazuki; Oota, Yoshitaka; Aibe, Norihiro; Nakamura, Satoaki; Yoshida, Ken; Okabe, Haruumi; Yamada, Kei

2014-05-05

Radiotherapy is a standard treatment for prostate cancer, and image-guided radiotherapy is increasingly being used to aid precision of dose delivery to targeted tissues. However, precision during radiotherapy cannot be maintained when unexpected intrafraction organ motion occurs. We report our experience of internal organ motion caused by persistent gas production in a patient taking an alpha-glucosidase inhibitor. A 68-year-old Japanese man with prostate cancer visited our institution for treatment with helical tomotherapy. He suffered from diabetes mellitus and took an alpha-glucosidase inhibitor. Routine treatment planning computed tomography showed a large volume of rectal gas; an enema was given to void the rectum. Subsequent treatment planning computed tomography again showed a large volume of gas. After exercise (walking) to remove the intestinal gas, a third scan was performed as a test scan without tight fixation, which showed a sufficiently empty rectum for planning. However, after only a few minutes, treatment planning computed tomography again showed extreme accumulation of gas. Therefore, we postponed treatment planning computed tomography and consulted his doctor to suspend the alpha-glucosidase inhibitor, which was the expected cause of his persistent gas. Four days after the alpha-glucosidase inhibitor regimen was suspended, we took a fourth treatment planning computed tomography and made a treatment plan without gas accumulation. Thereafter, the absence of rectal gas accumulation was confirmed using daily megavolt computed tomography before treatment, and the patient received 37 fractions of intensity-modified radiotherapy at 74 Gy without rectal gas complications. In this case study, the alpha-glucosidase inhibitor induced the accumulation of intestinal gas, which may have caused unexpected organ motion, untoward reactions, and insufficient doses to clinical targets. We suggest that patients who are taking an alpha-glucosidase inhibitor for diabetes should discontinue use of that particular medicine prior to beginning radiotherapy.

Adaptive radiotherapy for head and neck cancers: Fact or fallacy to improve therapeutic ratio?

PubMed

Li, Y Q; Tan, J S H; Wee, J T S; Chua, M L K

2018-04-23

Modern standards of precision radiotherapy, primarily driven by the technological advances of intensity modulation and image guidance, have led to increased versatility in radiotherapy planning and delivery. The ability to shape doses around critical normal organs, while simultaneously "painting" boost doses to the tumor have translated to substantial therapeutic gains in head and neck cancer patients. Recently, dose adaptation (or adaptive radiotherapy) has been proposed as a novel concept to enhance the therapeutic ratio of head and neck radiotherapy, facilitated in part by the onset of molecular and functional imaging. These contemporary imaging techniques have enabled visualisation of the spatial molecular architecture of the tumor. Daily cone-beam imaging, besides improving treatment accuracy, offers another unique angle to explore radiomics - a novel high throughput feature extraction and selection workflow, for adapting radiotherapy based on real-time tumor changes. Here, we review the existing evidence of molecular and functional imaging in head and neck cancers, as well as the current application of adaptive radiotherapy in the treatment of this tumor type. We propose that adaptive radiotherapy can be further exploited through a systematic application of molecular and functional imaging, including radiomics, at the different phases of planning and treatment. Copyright © 2018 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Oedema-based model for diffuse low-grade gliomas: application to clinical cases under radiotherapy.

PubMed

Badoual, M; Gerin, C; Deroulers, C; Grammaticos, B; Llitjos, J-F; Oppenheim, C; Varlet, P; Pallud, J

2014-08-01

Diffuse low-grade gliomas are characterized by slow growth. Despite appropriate treatment, they change inexorably into more aggressive forms, jeopardizing the patient's life. Optimizing treatments, for example with the use of mathematical modelling, could help to prevent tumour regrowth and anaplastic transformation. Here, we present a model of the effect of radiotherapy on such tumours. Our objective is to explain observed delay of tumour regrowth following radiotherapy and to predict its duration. We have used a migration-proliferation model complemented by an equation describing appearance and draining of oedema. The model has been applied to clinical data of tumour radius over time, for a population of 28 patients. We were able to show that draining of oedema accounts for regrowth delay after radiotherapy and have been able to fit the clinical data in a robust way. The model predicts strong correlation between high proliferation coefficient and low progression-free gain of lifetime, due to radiotherapy among the patients, in agreement with clinical studies. We argue that, with reasonable assumptions, it is possible to predict (precision ~20%) regrowth delay after radiotherapy and the gain of lifetime due to radiotherapy. Our oedema-based model provides an early estimation of individual duration of tumour response to radiotherapy and thus, opens the door to the possibility of personalized medicine. © 2014 John Wiley & Sons Ltd.

The impact of PET/CT scanning on the size of target volumes, radiation exposure of organs at risk, TCP and NTCP, in the radiotherapy planning of non-small cell lung cancer.

PubMed

Vojtíšek, Radovan; Mužík, Jan; Slampa, Pavel; Budíková, Marie; Hejsek, Jaroslav; Smolák, Petr; Ferda, Jiří; Fínek, Jindřich

2014-05-01

To compare radiotherapy plans made according to CT and PET/CT and to investigate the impact of changes in target volumes on tumour control probability (TCP), normal tissue complication probability (NTCP) and the impact of PET/CT on the staging and treatment strategy. Contemporary studies have proven that PET/CT attains higher sensitivity and specificity in the diagnosis of lung cancer and also leads to higher accuracy than CT alone in the process of target volume delineation in NSCLC. Between October 2009 and March 2012, 31 patients with locally advanced NSCLC, who had been referred to radical radiotherapy were involved in our study. They all underwent planning PET/CT examination. Then we carried out two separate delineations of target volumes and two radiotherapy plans and we compared the following parameters of those plans: staging, treatment purpose, the size of GTV and PTV and the exposure of organs at risk (OAR). TCP and NTCP were also compared. PET/CT information led to a significant decrease in the sizes of target volumes, which had the impact on the radiation exposure of OARs. The reduction of target volume sizes was not reflected in the significant increase of the TCP value. We found that there is a very strong direct linear relationship between all evaluated dosimetric parameters and NTCP values of all evaluated OARs. Our study found that the use of planning PET/CT in the radiotherapy planning of NSCLC has a crucial impact on the precise determination of target volumes, more precise staging of the disease and thus also on possible changes of treatment strategy.

A versatile program for the calculation of linear accelerator room shielding.

PubMed

Hassan, Zeinab El-Taher; Farag, Nehad M; Elshemey, Wael M

2018-03-22

This work aims at designing a computer program to calculate the necessary amount of shielding for a given or proposed linear accelerator room design in radiotherapy. The program (Shield Calculation in Radiotherapy, SCR) has been developed using Microsoft Visual Basic. It applies the treatment room shielding calculations of NCRP report no. 151 to calculate proper shielding thicknesses for a given linear accelerator treatment room design. The program is composed of six main user-friendly interfaces. The first enables the user to upload their choice of treatment room design and to measure the distances required for shielding calculations. The second interface enables the user to calculate the primary barrier thickness in case of three-dimensional conventional radiotherapy (3D-CRT), intensity modulated radiotherapy (IMRT) and total body irradiation (TBI). The third interface calculates the required secondary barrier thickness due to both scattered and leakage radiation. The fourth and fifth interfaces provide a means to calculate the photon dose equivalent for low and high energy radiation, respectively, in door and maze areas. The sixth interface enables the user to calculate the skyshine radiation for photons and neutrons. The SCR program has been successfully validated, precisely reproducing all of the calculated examples presented in NCRP report no. 151 in a simple and fast manner. Moreover, it easily performed the same calculations for a test design that was also calculated manually, and produced the same results. The program includes a new and important feature that is the ability to calculate required treatment room thickness in case of IMRT and TBI. It is characterised by simplicity, precision, data saving, printing and retrieval, in addition to providing a means for uploading and testing any proposed treatment room shielding design. The SCR program provides comprehensive, simple, fast and accurate room shielding calculations in radiotherapy.

The 1998 Australian external beam radiotherapy survey and IAEA/WHO TLD postal dose quality audit.

PubMed

Huntley, R; Izewska, J

2000-03-01

The results of an updated Australian survey of external beam radiotherapy centres are presented. Most of the centres provided most of the requested information. The relative caseloads of various linear accelerator photon and electron beams have not changed significantly since the previous survey in 1995. The mean age of Australian LINACs is 7.1 years and that of other radiotherapy machines is 14.7 years. Every Australian radiotherapy centre participated in a special run of the IAEA/WHO TLD postal dose quality audit program, which was provided for Australian centres by the IAEA and WHO in May 1998. The dose quoted by the centres was in nearly every case within 1.5% of the dose assessed by the IAEA. This is within the combined standard uncertainty of the IAEA TLD service (1.8%). The results confirm the accuracy and precision of radiotherapy dosimetry in Australia and the adequate dissemination of the Australian standards from ARL (now ARPANSA) to the centres. The Australian standards have recently been shown to agree with those of other countries to within 0.25% by comparison with the BIPM.

Protons and more: state of the art in radiotherapy.

PubMed

Hoskin, Peter J; Bhattacharya, Indrani S

2014-12-01

The purpose of modern radiotherapy is to deliver a precise high dose of radiation which will result in reproductive death of the cells. Radiation should transverse within the tumour volume whilst minimising damage to surrounding normal tissue. Overall 40% of cancers which are cured will have received radiotherapy. Current state of the art treatment will incorporate cross-sectional imaging and multiple high energy X-ray beams in processes called intensity modulated radiotherapy and image guided radiotherapy. Brachytherapy enables very high radiation doses to be delivered by the direct passage of a radiation source through or within the tumour volume and similar results can be achieved using rotational stereotactic X-ray beam techniques. Protons have the characteristics of particle beams which deposit their energy in a finite fixed peak at depth in tissue with no dose beyond this point - the Bragg peak. This has advantages in certain sites such as the spine adjacent to the spinal cord and particularly in children when the overall volume of tissue receiving radiation can be minimised. © 2014 Royal College of Physicians.

The role of PET in target localization for radiotherapy treatment planning.

PubMed

Rembielak, Agata; Price, Pat

2008-02-01

Positron emission tomography (PET) is currently accepted as an important tool in oncology, mostly for diagnosis, staging and restaging purposes. It provides a new type of information in radiotherapy, functional rather than anatomical. PET imaging can also be used for target volume definition in radiotherapy treatment planning. The need for very precise target volume delineation has arisen with the increasing use of sophisticated three-dimensional conformal radiotherapy techniques and intensity modulated radiation therapy. It is expected that better delineation of the target volume may lead to a significant reduction in the irradiated volume, thus lowering the risk of treatment complications (smaller safety margins). Better tumour visualisation also allows a higher dose of radiation to be applied to the tumour, which may lead to better tumour control. The aim of this article is to review the possible use of PET imaging in the radiotherapy of various cancers. We focus mainly on non-small cell lung cancer, lymphoma and oesophageal cancer, but also include current opinion on the use of PET-based planning in other tumours including brain, uterine cervix, rectum and prostate.

PRESAGE® as a solid 3-D radiation dosimeter: A review article

NASA Astrophysics Data System (ADS)

Khezerloo, Davood; Nedaie, Hassan Ali; Takavar, Abbas; Zirak, Alireza; Farhood, Bagher; Movahedinejhad, Hadi; Banaee, Nooshin; Ahmadalidokht, Isa; Knuap, Courtney

2017-12-01

Radiation oncology has been rapidly improved by the application of new equipment and techniques. With the advent of new complex and precise radiotherapy techniques such as intensity modulated radiotherapy, stereotactic radiosurgery, and volumetric modulated arc therapy, the demand for an accurate and feasible three-dimensional (3-D) dosimetry system has increased. The most important features of a 3-D dosimeter, apart from being precise, accurate and reproducible, include also its low cost, feasibility, and availability. In 2004 a new generation of solid plastic dosimeters which demonstrate a radiochromic response to ionizing radiation was introduced. PRESAGE® plastic dosimeter lacks the limitations of previous Ferric and polymer plastic 3-D dosimeters such as diffusion, sensitivity to oxygen, fabrication problems, scanning and read out challenges. In this decade, a large number of efforts have been carried out to enhance PRESAGE® structure and scanning methods. This article attempts to review and reflect on the results of these investigations.

Five-year follow-up using a prostate stent as fiducial in image-guided radiotherapy of prostate cancer.

PubMed

Carl, Jesper; Sander, Lotte

2015-06-01

To report results from the five-year follow-up on a previously reported study using image-guided radiotherapy (IGRT) of localized or locally advanced prostate cancer (PC) and a removable prostate stent as fiducial. Patients with local or locally advanced PC were treated using five-field 3D conformal radiotherapy (3DRT). The clinical target volumes (CTV) were treated to 78 Gy in 39 fractions using daily on-line image guidance (IG). Late genito-urinary (GU) and gastro-intestinal (GI) toxicities were scored using the radiotherapy oncology group (RTOG) score and the common toxicity score of adverse events (CTC) score. Urinary symptoms were also scored using the international prostate symptom score (IPSS). Median observation time was 5.4 year. Sixty-two of the 90 patients from the original study cohort were eligible for toxicity assessment. Overall survival, cancer-specific survival and biochemical freedom from failure were 85%, 96% and 80%, respectively at five years after radiotherapy. Late toxicity GU and GI RTOG scores≥2 were 5% and 0%. Comparing pre- and post-radiotherapy IPSS scores indicate that development in urinary symptoms after radiotherapy may be complex. Prostate image-guided radiotherapy using a prostate stent demonstrated survival data comparable with recently published data. GU and GI toxicities at five-year follow-up were low and comparable to the lowest toxicity rates reported. These findings support that the precision of the prostate stent technique is at least as good as other techniques. IPSS revealed a complex development in urinary symptoms after radiotherapy.

Health economics in radiation oncology: introducing the ESTRO HERO project.

PubMed

Lievens, Yolande; Grau, Cai

2012-04-01

New evidence based regimens and novel high precision technology have reinforced the important role of radiotherapy in the management of cancer. Current data estimate that more than 50% of all cancer patients would benefit from radiotherapy during the course of their disease. Within recent years, the radiotherapy community has become more than conscious of the ever-increasing necessity to come up with objective data to endorse the crucial role and position of radiation therapy within the rapidly changing global oncology landscape. In an era of ever expanding health care costs, proven safety and effectiveness is not sufficient anymore to obtain funding, objective data about cost and cost-effectiveness are nowadays additionally requested. It is in this context that ESTRO is launching the HERO-project (Health Economics in Radiation Oncology), with the overall aim to develop a knowledge base and a model for health economic evaluation of radiation treatments at the European level. To accomplish these objectives, the HERO project will address needs, accessibility, cost and cost-effectiveness of radiotherapy. The results will raise the profile of radiotherapy in the European cancer management context and help countries prioritizing radiotherapy as a highly cost-effective treatment strategy. This article describes the different steps and aims within the HERO-project, starting from evidence on the role of radiotherapy within the global oncology landscape and highlighting weaknesses that may undermine this position. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Everything Old Is New Again: Using Nelfinavir to Radiosensitize Rectal Cancer

PubMed Central

Meyn, Raymond E.; Krishnan, Sunil; Skinner, Heath D.

2016-01-01

Summary Repurposing agents approved for other indications to radiosensitize tumors may be advantageous. The study by Hill and colleagues utilizes Nelfinavir, an HIV protease inhibitor, in combination with radiotherapy in rectal cancer in a prospective study. This combination may improve tumor perfusion and regression compared to radiotherapy alone. PMID:26920893

A case study of the neuropsychological outcomes following microsurgery, conventional radiotherapy and stereotactic radiotherapy for an adult's recurrent craniopharyngioma.

PubMed

Preece, David; Allan, Alfred; Becerra, Rodrigo

2016-01-01

To examine the neuropsychological outcomes for an adult patient, 2 years after receiving microsurgery and conventional radiotherapy for a recurrent craniopharyngioma; and the impact of a further intervention, stereotactic radiotherapy, on this level of neuropsychological functioning. JD, a 30 year old male whose recurrent craniopharyngioma had 2 years earlier been treated with two operations and conventional radiotherapy. JD was assessed (using standardized clinical tests) before and after a course of stereotactic radiotherapy. Prior to stereotactic radiotherapy (and 2 years after microsurgery and conventional radiotherapy) JD's IQ was intact, but considerable impairments were present in executive functioning, memory, theory of mind and processing speed. Fifteen months after stereotactic radiotherapy, all neuropsychological domains remained largely static or improved, supporting the utility of this treatment option in the neuropsychological domain. However, deficits in executive functioning, memory and processing speed remained. These findings suggest that, even after multiple treatments, substantial cognitive impairments can be present in an adult patient with a recurrent craniopharyngioma. This profile of deficits underlines the inadequacy of relying purely on IQ as a marker for cognitive health in this population and emphasizes the need to include neuropsychological impairments as a focus of rehabilitation with these patients.

Radiosurgery and radiotherapy for sacral tumors.

PubMed

Gibbs, Iris C; Chang, Steven D

2003-08-15

Sacral tumors represent a small subset of spinal lesions and typically include chordomas, metastases, other primary bone tumors, and benign schwannomas. Resection is the standard treatment for many sacral tumors, but many types of sacral lesions have the potential for recurrence after excision. In these cases, adjuvant radiotherapy is often beneficial. Although conventional radiotherapy plays an important role in the management of spinal lesions, the radiation doses required for adequate local control of many sacral lesions generally exceed the tolerance doses of normal tissues, thus limiting its definitive role in the management of sacral tumors. Recent advances in the field of stereotactic radiosurgery have allowed precise targeting of the sacrum. In this report the authors review the use of these two forms of radiation treatment and their role in managing sacral tumors.

Experiences with an application of industrial robotics for accurate patient positioning in proton radiotherapy.

PubMed

Allgower, C E; Schreuder, A N; Farr, J B; Mascia, A E

2007-03-01

Protons beams deliver targeted radiation doses with greater precision than is possible with electrons or megavoltage X-ray photons, but to retain this advantage, patient positioning systems at proton clinics must meet tighter accuracy requirements. For this and other reasons, robots were incorporated into the treatment room systems at MPRI. The Midwest Proton Radiotherapy Institute (MPRI) is the first radiotherapy facility in the United States to use commercial robots with six degrees of freedom for patient positioning, rather than a traditional bed with four degrees of freedom. This paper outlines the ways in which robots are used at MPRI and attempts to distil insights from the experience of treating over 200 radiotherapy patients with a robotic system from February 2004 to late 2006. The system has performed well, and with great reliability, but there is room for future improvement, especially in ease of use and in reducing the time to get patients into position. Copyright 2006 John Wiley & Sons, Ltd.

A feasibility study of treatment verification using EPID cine images for hypofractionated lung radiotherapy

NASA Astrophysics Data System (ADS)

Tang, Xiaoli; Lin, Tong; Jiang, Steve

2009-09-01

We propose a novel approach for potential online treatment verification using cine EPID (electronic portal imaging device) images for hypofractionated lung radiotherapy based on a machine learning algorithm. Hypofractionated radiotherapy requires high precision. It is essential to effectively monitor the target to ensure that the tumor is within the beam aperture. We modeled the treatment verification problem as a two-class classification problem and applied an artificial neural network (ANN) to classify the cine EPID images acquired during the treatment into corresponding classes—with the tumor inside or outside of the beam aperture. Training samples were generated for the ANN using digitally reconstructed radiographs (DRRs) with artificially added shifts in the tumor location—to simulate cine EPID images with different tumor locations. Principal component analysis (PCA) was used to reduce the dimensionality of the training samples and cine EPID images acquired during the treatment. The proposed treatment verification algorithm was tested on five hypofractionated lung patients in a retrospective fashion. On average, our proposed algorithm achieved a 98.0% classification accuracy, a 97.6% recall rate and a 99.7% precision rate. This work was first presented at the Seventh International Conference on Machine Learning and Applications, San Diego, CA, USA, 11-13 December 2008.

A fuzzy feature fusion method for auto-segmentation of gliomas with multi-modality diffusion and perfusion magnetic resonance images in radiotherapy.

PubMed

Guo, Lu; Wang, Ping; Sun, Ranran; Yang, Chengwen; Zhang, Ning; Guo, Yu; Feng, Yuanming

2018-02-19

The diffusion and perfusion magnetic resonance (MR) images can provide functional information about tumour and enable more sensitive detection of the tumour extent. We aimed to develop a fuzzy feature fusion method for auto-segmentation of gliomas in radiotherapy planning using multi-parametric functional MR images including apparent diffusion coefficient (ADC), fractional anisotropy (FA) and relative cerebral blood volume (rCBV). For each functional modality, one histogram-based fuzzy model was created to transform image volume into a fuzzy feature space. Based on the fuzzy fusion result of the three fuzzy feature spaces, regions with high possibility belonging to tumour were generated automatically. The auto-segmentations of tumour in structural MR images were added in final auto-segmented gross tumour volume (GTV). For evaluation, one radiation oncologist delineated GTVs for nine patients with all modalities. Comparisons between manually delineated and auto-segmented GTVs showed that, the mean volume difference was 8.69% (±5.62%); the mean Dice's similarity coefficient (DSC) was 0.88 (±0.02); the mean sensitivity and specificity of auto-segmentation was 0.87 (±0.04) and 0.98 (±0.01) respectively. High accuracy and efficiency can be achieved with the new method, which shows potential of utilizing functional multi-parametric MR images for target definition in precision radiation treatment planning for patients with gliomas.

Real-time optical measurement of the dynamic body surface for use in guided radiotherapy

NASA Astrophysics Data System (ADS)

Price, G. J.; Parkhurst, J. M.; Sharrock, P. J.; Moore, C. J.

2012-01-01

Optical measurements are increasingly used in radiotherapy. In this paper we present, in detail, the design and implementation of a multi-channel optical system optimized for fast, high spatial resolution, dynamic body surface measurement in guided therapy. We include all algorithmic modifications and calibration procedures required to create a robust, practical system for clinical use. Comprehensive static and dynamic phantom validation measurements in the radiotherapy treatment room show: conformance with simultaneously measured cone beam CT data to within 1 mm over 62% ± 8% of the surface and 2 mm over 90% ± 3%; agreement with the measured radius of a precision geometrical phantom to within 1 mm; and true real-time performance with image capture through to surface display at 23 Hz. An example patient dataset is additionally included, indicating similar performance in the clinic.

Teleradiotherapy Network: Applications and Feasibility for Providing Cost-Effective Comprehensive Radiotherapy Care in Low- and Middle-Income Group Countries for Cancer Patients

PubMed Central

Heuser, Michael; Samiei, Massoud; Shah, Ragesh; Lutters, Gerd; Bodis, Stephan

2015-01-01

Abstract Globally, new cancer cases will rise by 57% within the next two decades, with the majority in the low- and middle-income countries (LMICs). Consequently, a steep increase of about 40% in cancer deaths is expected there, mainly because of lack of treatment facilities, especially radiotherapy. Radiotherapy is required for more than 50% of patients, but the capital cost for equipment often deters establishment of such facilities in LMICs. Presently, of the 139 LMICs, 55 do not even have a radiotherapy facility, whereas the remaining 84 have a deficit of 61.4% of their required radiotherapy units. Networking between centers could enhance the effectiveness and reach of existing radiotherapy in LMICs. A teleradiotherapy network could enable centers to share and optimally utilize their resources, both infrastructure and staffing. This could be in the form of a three-tier radiotherapy service consisting of primary, secondary, and tertiary radiotherapy centers interlinked through a network. The concept has been adopted in some LMICs and could also be used as a “service provider model,” thereby reducing the investments to set up such a network. Teleradiotherapy networks could be a part of the multipronged approach to address the enormous gap in radiotherapy services in a cost-effective manner and to support better accessibility to radiotherapy facilities, especially for LMICs. PMID:25763906

Teleradiotherapy Network: Applications and Feasibility for Providing Cost-Effective Comprehensive Radiotherapy Care in Low- and Middle-Income Group Countries for Cancer Patients.

PubMed

Datta, Niloy Ranjan; Heuser, Michael; Samiei, Massoud; Shah, Ragesh; Lutters, Gerd; Bodis, Stephan

2015-07-01

Globally, new cancer cases will rise by 57% within the next two decades, with the majority in the low- and middle-income countries (LMICs). Consequently, a steep increase of about 40% in cancer deaths is expected there, mainly because of lack of treatment facilities, especially radiotherapy. Radiotherapy is required for more than 50% of patients, but the capital cost for equipment often deters establishment of such facilities in LMICs. Presently, of the 139 LMICs, 55 do not even have a radiotherapy facility, whereas the remaining 84 have a deficit of 61.4% of their required radiotherapy units. Networking between centers could enhance the effectiveness and reach of existing radiotherapy in LMICs. A teleradiotherapy network could enable centers to share and optimally utilize their resources, both infrastructure and staffing. This could be in the form of a three-tier radiotherapy service consisting of primary, secondary, and tertiary radiotherapy centers interlinked through a network. The concept has been adopted in some LMICs and could also be used as a "service provider model," thereby reducing the investments to set up such a network. Teleradiotherapy networks could be a part of the multipronged approach to address the enormous gap in radiotherapy services in a cost-effective manner and to support better accessibility to radiotherapy facilities, especially for LMICs.

SU-F-J-59: Assessment of Dose Response Distribution in Individual Human Tumor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, D; Chen, S; Krauss, D

Purpose: To fulfill precision radiotherapy via adaptive dose painting by number, voxel-by-voxel dose response or radio-sensitivity in individual human tumor needs to be determined in early treatment to guide treatment adaptation. In this study, multiple FDG PET images obtained pre- and weekly during the treatment course were utilized to determine the distribution/spectrum of dose response parameters in individual human tumors. Methods: FDG PET/CT images of 18 HN cancer patients were used in the study. Spatial parametric image of tumor metabolic ratio (dSUV) was created following voxel by voxel deformable image registration. Each voxel value in dSUV was a function ofmore » pre-treatment baseline SUV and treatment delivered dose, and used as a surrogate of tumor survival fraction (SF). Regression fitting with break points was performed using the LQ-model with tumor proliferation for the control and failure group of tumors separately. The distribution and spectrum of radiation sensitivity and growth in individual tumors were determined and evaluated. Results: Spectrum of tumor dose-sensitivity and proliferation in the controlled group was broad with α in tumor survival LQ-model from 0.17 to 0.8. It was proportional to the baseline SUV. Tlag was about 21∼25 days, and Tpot about 0.56∼1.67 days respectively. Commonly tumor voxels with high radio-sensitivity or larger α had small Tlag and Tpot. For the failure group, the radio-sensitivity α was low within 0.05 to 0.3, but did not show clear Tlag. In addition, tumor voxel radio-sensitivity could be estimated during the early treatment weeks. Conclusion: Dose response distribution with respect to radio-sensitivity and growth in individual human tumor can be determined using FDG PET imaging based tumor metabolic ratio measured in early treatment course. The discover is critical and provides a potential quantitative objective to implement tumor specific precision radiotherapy via adaptive dose painting by number.« less

Navigators for motion detection during real-time MRI-guided radiotherapy

NASA Astrophysics Data System (ADS)

Stam, Mette K.; Crijns, Sjoerd P. M.; Zonnenberg, Bernard A.; Barendrecht, Maurits M.; van Vulpen, Marco; Lagendijk, Jan J. W.; Raaymakers, Bas W.

2012-11-01

An MRI-linac system provides direct MRI feedback and with that the possibility of adapting radiation treatments to the actual tumour position. This paper addresses the use of fast 1D MRI, pencil-beam navigators, for this feedback. The accuracy of using navigators was determined on a moving phantom. The possibility of organ tracking and breath-hold monitoring based on navigator guidance was shown for the kidney. Navigators are accurate within 0.5 mm and the analysis has a minimal time lag smaller than 30 ms as shown for the phantom measurements. The correlation of 2D kidney images and navigators shows the possibility of complete organ tracking. Furthermore the breath-hold monitoring of the kidney is accurate within 1.5 mm, allowing gated radiotherapy based on navigator feedback. Navigators are a fast and precise method for monitoring and real-time tracking of anatomical landmarks. As such, they provide direct MRI feedback on anatomical changes for more precise radiation delivery.

Associated factors of radiation pneumonitis induced by precise radiotherapy in 186 elderly patients with esophageal cancer.

PubMed

Cui, Zhen; Tian, Ye; He, Bin; Li, Hongwei; Li, Duojie; Liu, Jingjing; Cai, Hanfei; Lou, Jianjun; Jiang, Hao; Shen, Xueming; Peng, Kaigui

2015-01-01

Radiation pneumonitis is one of the most severe complications of esophageal cancer. To explore the factors correlated to radiation pneumonitis induced by precise radiotherapy for elderly patients with esophageal cancer. The retrospective analysis was used to collect clinical data from 186 elderly patients with esophageal cancer. The incidence of radiation pneumonitis was observed, followed by statistical analysis through ANVON or multiple regression analysis. 27 in 186 cases of esophageal cancer suffered from radiation pneumonitis, with incidence of 14.52%. The single factor analysis showed that, Karnofsky performance status (KPS) score, chronic obstructive pulmonary disease, concurrent chemoradiotherapy, gross tumor volume (GTV) dose, lung V20, mean lung dose (MLD) and planning target volume (PTV) were associated with radiation pneumonitis. The logistic regression analysis indicated that, concurrent chemoradiotherapy, GTV dose, lung V20 and PTV were the independent factors of radiation pneumonitis. The concurrent chemoradiotherapy, GTV dose, lung V20, MLD and PTV are the major risk factors of radiation pneumonitis for elderly patients with esophageal cancer.

Improving external beam radiotherapy by combination with internal irradiation.

PubMed

Dietrich, A; Koi, L; Zöphel, K; Sihver, W; Kotzerke, J; Baumann, M; Krause, M

2015-07-01

The efficacy of external beam radiotherapy (EBRT) is dose dependent, but the dose that can be applied to solid tumour lesions is limited by the sensitivity of the surrounding tissue. The combination of EBRT with systemically applied radioimmunotherapy (RIT) is a promising approach to increase efficacy of radiotherapy. Toxicities of both treatment modalities of this combination of internal and external radiotherapy (CIERT) are not additive, as different organs at risk are in target. However, advantages of both single treatments are combined, for example, precise high dose delivery to the bulk tumour via standard EBRT, which can be increased by addition of RIT, and potential targeting of micrometastases by RIT. Eventually, theragnostic radionuclide pairs can be used to predict uptake of the radiotherapeutic drug prior to and during therapy and find individual patients who may benefit from this treatment. This review aims to highlight the outcome of pre-clinical studies on CIERT and resultant questions for translation into the clinic. Few clinical data are available until now and reasons as well as challenges for clinical implementation are discussed.

Very High Dose-Rate Radiobiology and Radiation Therapy for Lung Cancer

DTIC Science & Technology

2015-02-01

most dramatic example is stereotactic ablative radiotherapy ( SABR )/ stereotactic body radiation therapy (SBRT), highly focused and accurate...significant motion, thus increasing the precision and accuracy of lung SABR /SBRT. Objective: We propose to develop a new type of RT system for early stage

Image registration assessment in radiotherapy image guidance based on control chart monitoring.

PubMed

Xia, Wenyao; Breen, Stephen L

2018-04-01

Image guidance with cone beam computed tomography in radiotherapy can guarantee the precision and accuracy of patient positioning prior to treatment delivery. During the image guidance process, operators need to take great effort to evaluate the image guidance quality before correcting a patient's position. This work proposes an image registration assessment method based on control chart monitoring to reduce the effort taken by the operator. According to the control chart plotted by daily registration scores of each patient, the proposed method can quickly detect both alignment errors and image quality inconsistency. Therefore, the proposed method can provide a clear guideline for the operators to identify unacceptable image quality and unacceptable image registration with minimal effort. Experimental results demonstrate that by using control charts from a clinical database of 10 patients undergoing prostate radiotherapy, the proposed method can quickly identify out-of-control signals and find special cause of out-of-control registration events.

Role of particle radiotherapy in the management of head and neck cancer.

PubMed

Laramore, George E

2009-05-01

Modern imaging techniques and powerful computers allow a radiation oncologist to design treatments delivering higher doses of radiation than previously possible. Dose distributions imposed by the physics of 'standard' photon and electron beams limit further dose escalation. Hadron radiotherapy offers advantages in either dose distribution and/or improved radiobiology that may significantly improve the treatment of certain head and neck malignancies. Clinical studies support the effectiveness of fast-neutron radiotherapy in the treatment of major and minor salivary gland tumors. Data show highly favorable outcomes with proton radiotherapy for skull-base malignancies and tumors near highly critical normal tissues compared with that expected with standard radiotherapy. Heavy-ion radiotherapy clinical studies are mainly being conducted with fully stripped carbon ions, and limited data seem to indicate a possible improvement over proton radiotherapy for the same subset of radioresistant tumors where neutrons show a benefit over photons. Fast-neutron radiotherapy has different radiobiological properties compared with standard radiotherapy but similar depth dose distributions. Its role in the treatment of head and neck cancer is currently limited to salivary gland malignancies and certain radioresistant tumors such as sarcomas. Protons have the same radiobiological properties as standard radiotherapy beams but more optimal depth dose distributions, making it particularly advantageous when treating tumors adjacent to highly critical structures. Heavy ions combine the radiobiological properties of fast neutrons with the physical dose distributions of protons, and preliminary data indicate their utility for radioresistant tumors adjacent to highly critical structures.

Does a too risk-averse approach to the implementation of new radiotherapy technologies delay their clinical use?

PubMed

Garcia, R; Nyström, H; Fiorino, C; Thwaites, D

2015-07-01

Radiotherapy is a generally safe treatment modality in practice; nevertheless, recent well-reported accidents also confirm its potential risks. However, this may obstruct or delay the introduction of new technologies and treatment strategies/techniques into clinical practice. Risks must be addressed and judged in a realistic context: risks must be assessed realistically. Introducing new technology may introduce new possibilities of errors. However, delaying the introduction of such new technology therefore means that patients are denied the potentially better treatment opportunities. Despite the difficulty in quantitatively assessing the risks on both sides of the possible choice of actions, including the "lost opportunity", the best estimates should be included in the overall risk-benefit and cost-benefit analysis. Radiotherapy requires a sufficiently high level of support for the safety, precision and accuracy required: radiotherapy development and implementation is exciting. However, it has been anxious with a constant awareness of the consequences of mistakes or misunderstandings. Recent history can be used to show that for introduction of advanced radiotherapy, the risk-averse medical physicist can act as an electrical fuse in a complex circuit. The lack of sufficient medical physics resource or expertise can short out this fuse and leave systems unsafe. Future technological developments will continue to present further safety and risk challenges. The important evolution of radiotherapy brings different management opinions and strategies. Advanced radiotherapy technologies can and should be safely implemented in as timely a manner as possible for the patient groups where clinical benefit is indicated.

Reproducibility of patient positioning for fractionated extracranial stereotactic radiotherapy using a double-vacuum technique.

PubMed

Nevinny-Stickel, Meinhard; Sweeney, Reinhart A; Bale, Reto J; Posch, Andrea; Auberger, Thomas; Lukas, Peter

2004-02-01

Precise reproducible patient positioning is a prerequisite for conformal fractionated radiotherapy. A fixation system based on double-vacuum technology is presented which can be used for conventional as well as hypofractionated stereotactic extracranial radiotherapy. To form the actual vacuum mattress, the patient is pressed into the mattress with a vacuum foil which can also be used for daily repositioning and fixation. A stereotactic frame can be positioned over the region of interest on an indexed base plate. Repositioning accuracy was determined by comparing daily, pretreatment, orthogonal portal images to the respective digitally reconstructed radiographs (DRRs) in ten patients with abdominal and pelvic lesions receiving extracranial fractionated (stereotactic) radiotherapy. The three-dimensional (3-D) vectors and 95% confidence intervals (CI) were calculated from the respective deviations in the three axes. Time required for initial mold production and daily repositioning was also determined. The mean 3-D repositioning error (187 fractions) was 2.5 +/- 1.1 mm. The largest single deviation (10 mm) was observed in a patient treated in prone position. Mold production took an average of 15 min (10-30 min). Repositioning times are not necessarily longer than using no positioning aid at all. The presented fixation system allows reliable, flexible and efficient patient positioning for extracranial stereotactic radiotherapy.

Radiotherapy utilization in developing countries: An IAEA study.

PubMed

Rosenblatt, Eduardo; Fidarova, Elena; Zubizarreta, Eduardo H; Barton, Michael B; Jones, Glenn W; Mackillop, William J; Cordero, Lisbeth; Yarney, Joel; Lim, Gerard; Gan, John V; Cernea, Valentin; Stojanovic-Rundic, Suzana; Strojan, Primoz; Kochbati, Lotfi; Quarneti, Aldo

2018-05-30

The planning of national radiotherapy (RT) services requires a thorough knowledge of the country's cancer epidemiology profile, the radiotherapy utilization (RTU) rates and a future projection of these data. Previous studies have established RTU rates in high-income countries. Optimal RTU (oRTU) rates were determined for nine middle-income countries, following the epidemiological evidence-based method. The actual RTU (aRTU) rates were calculated dividing the total number of new notifiable cancer patients treated with radiotherapy in 2012 by the total number of cancer patients diagnosed in the same year in each country. An analysis of the characteristics of patients and treatments in a series of 300 consecutive radiotherapy patients shed light on the particular patient and treatments profile in the participating countries. The median oRTU rate for the group of nine countries was 52% (47-56%). The median aRTU rate for the nine countries was 28% (9-46%). These results show that the real proportion of cancer patients receiving RT is lower than the optimal RTU with a rate difference between 10-42.7%. The median percent-unmet need was 47% (18-82.3%). The optimal RTU rate in middle-income countries did not differ significantly from that previously found in high-income countries. The actual RTU rates were consistently lower than the optimal, in particular in countries with limited resources and a large population. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

[Clinical evaluation of heavy-particle radiotherapy using dose volume histogram (DVH)].

PubMed

Terahara, A; Nakano, T; Tsujii, H

1998-01-01

Radiotherapy with heavy particles such as proton and heavy-charged particles is a promising modality for treatment of localized malignant tumors because of the good dose distribution. A dose calculation and radiotherapy planning system which is essential for this kind of treatment has been developed in recent years. It has the capability to compute the dose volume histogram (DVH) which contains dose-volume information for the target volume and other interesting volumes. Recently, DVH is commonly used to evaluate and compare dose distributions in radiotherapy with both photon and heavy particles, and it shows that a superior dose distribution is obtained in heavy particle radiotherapy. DVH is also utilized for the evaluation of dose distribution related to clinical outcomes. Besides models such as normal tissue complication probability (NTCP) and tumor control probability (TCP), which can be calculated from DVH are proposed by several authors, they are applied to evaluate dose distributions themselves and to evaluate them in relation to clinical results. DVH is now a useful and important tool, but further studies are needed to use DVH and these models practically for clinical evaluation of heavy-particle radiotherapy.

[Cervix cancer].

PubMed

Pointreau, Y; Ruffier Loubière, A; Denis, F; Barillot, I

2010-11-01

Cervix cancers declined in most developed countries in recent years, but remain, the third worldwide leading cause of cancer death in women. A precise staging, based on clinical exam, an abdominal and pelvic MRI, a possible PET-CT and a possible lymph node sampling is necessary to adapt the best therapeutic strategy. In France, the treatments of tumors of less than 4 cm without nodal involvement are often based on radiotherapy followed by surgery and, whereas tumors larger than 4 cm and involved nodes are treated with concurrent chemoradiotherapy. Based on an illustrated clinical case, indications, delineation, dosimetry and complications expected with radiotherapy are demonstrated. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

Clinical utility of RapidArc™ radiotherapy technology

PubMed Central

Infusino, Erminia

2015-01-01

RapidArc™ is a radiation technique that delivers highly conformal dose distributions through the complete rotation (360°) and speed variation of the linear accelerator gantry. This technique, called volumetric modulated arc therapy (VMAT), compared with conventional radiotherapy techniques, can achieve high-target volume coverage and sparing damage to normal tissues. RapidArc delivers precise dose distribution and conformity similar to or greater than intensity-modulated radiation therapy in a short time, generally a few minutes, to which image-guided radiation therapy is added. RapidArc has become a currently used technology in many centers, which use RapidArc technology to treat a large number of patients. Large and small hospitals use it to treat the most challenging cases, but more and more frequently for the most common cancers. The clinical use of RapidArc and VMAT technology is constantly growing. At present, a limited number of clinical data are published, mostly concerning planning and feasibility studies. Clinical outcome data are increasing for a few tumor sites, even if only a little. The purpose of this work is to discuss the current status of VMAT techniques in clinical use through a review of the published data of planning systems and clinical outcomes in several tumor sites. The study consisted of a systematic review based on analysis of manuscripts retrieved from the PubMed, BioMed Central, and Scopus databases by searching for the keywords “RapidArc”, “Volumetric modulated arc radiotherapy”, and “Intensity-modulated radiotherapy”. PMID:26648755

TU-PIS-Exhibit Hall-2: How to Move Beyond Dose Monitoring to Imaging Performance Utilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valencia, D.

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has highmore » temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant.« less

[Porting Radiotherapy Software of Varian to Cloud Platform].

PubMed

Zou, Lian; Zhang, Weisha; Liu, Xiangxiang; Xie, Zhao; Xie, Yaoqin

2017-09-30

To develop a low-cost private cloud platform of radiotherapy software. First, a private cloud platform which was based on OpenStack and the virtual GPU hardware was builded. Then on the private cloud platform, all the Varian radiotherapy software modules were installed to the virtual machine, and the corresponding function configuration was completed. Finally the software on the cloud was able to be accessed by virtual desktop client. The function test results of the cloud workstation show that a cloud workstation is equivalent to an isolated physical workstation, and any clients on the LAN can use the cloud workstation smoothly. The cloud platform transplantation in this study is economical and practical. The project not only improves the utilization rates of radiotherapy software, but also makes it possible that the cloud computing technology can expand its applications to the field of radiation oncology.

A method for depth-dose distribution measurements in tissue irradiated by a proton beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gambarini, G.; Birattari, C.; Bartolo, D. de

1994-12-31

The use of protons and heavy ions for the treatment of malignant and non-malignant disease has aroused a growing interest in the last decade. The notable advantage of heavy charged particles over photons in external beam radiotherapy lies in the possibility of irradiating a small localized region within the body, keeping a low value for the entrance dose. Owing to this high disuniformity of energy deposition, an essential requirement for treatment planning is a precise evaluation of the spatial distribution of absorbed dose. The proposed method for depth-dose distribution measurements utilizes a chemical dosimeter (ferrous sulphate solution plus sulfuric acidmore » and eventually xylenol orange) incorporated in a gelatine, whose role is the maintenance of spatial information. Ionizing radiation causes a variation in some parameters of the system such as the proton relaxation rates in the solution (measurable by NMR analysis) or the optical absorption of the gel in the visible spectrum (measurable by spectrophotometry).« less

Discovery and Validation of Predictive Biomarkers of Survival for Non-small Cell Lung Cancer Patients Undergoing Radical Radiotherapy: Two Proteins With Predictive Value

PubMed Central

Walker, Michael J.; Zhou, Cong; Backen, Alison; Pernemalm, Maria; Williamson, Andrew J.K.; Priest, Lynsey J.C.; Koh, Pek; Faivre-Finn, Corinne; Blackhall, Fiona H.; Dive, Caroline; Whetton, Anthony D.

2015-01-01

Lung cancer is the most frequent cause of cancer-related death world-wide. Radiotherapy alone or in conjunction with chemotherapy is the standard treatment for locally advanced non-small cell lung cancer (NSCLC). Currently there is no predictive marker with clinical utility to guide treatment decisions in NSCLC patients undergoing radiotherapy. Identification of such markers would allow treatment options to be considered for more effective therapy. To enable the identification of appropriate protein biomarkers, plasma samples were collected from patients with non-small cell lung cancer before and during radiotherapy for longitudinal comparison following a protocol that carries sufficient power for effective discovery proteomics. Plasma samples from patients pre- and during radiotherapy who had survived > 18 mo were compared to the same time points from patients who survived < 14 mo using an 8 channel isobaric tagging tandem mass spectrometry discovery proteomics platform. Over 650 proteins were detected and relatively quantified. Proteins which showed a change during radiotherapy were selected for validation using an orthogonal antibody-based approach. Two of these proteins were verified in a separate patient cohort: values of CRP and LRG1 combined gave a highly significant indication of extended survival post one week of radiotherapy treatment. PMID:26425690

Radiation-induced immune responses: mechanisms and therapeutic perspectives.

PubMed

Jeong, Hoibin; Bok, Seoyeon; Hong, Beom-Ju; Choi, Hyung-Seok; Ahn, G-One

2016-09-01

Recent advancement in the radiotherapy technology has allowed conformal delivery of high doses of ionizing radiation precisely to the tumors while sparing large volume of the normal tissues, which have led to better clinical responses. Despite this technological advancement many advanced tumors often recur and they do so within the previously irradiated regions. How could tumors recur after receiving such high ablative doses of radiation? In this review, we outlined how radiation can elicit anti-tumor responses by introducing some of the cytokines that can be induced by ionizing radiation. We then discuss how tumor hypoxia, a major limiting factor responsible for failure of radiotherapy, may also negatively impact the anti-tumor responses. In addition, we highlight how there may be other populations of immune cells including regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), and tumor-associated macrophages (TAMs) that can be recruited to tumors interfering with the anti-tumor immunity. Finally, the impact of irradiation on tumor hypoxia and the immune responses according to different radiotherapy regimen is also delineated. It is indeed an exciting time to see that radiotherapy is being combined with immunotherapy in the clinic and we hope that this review can add an excitement to the field.

Influence of (11)C-choline PET/CT on radiotherapy planning in prostate cancer.

PubMed

López, Escarlata; Lazo, Antonio; Gutiérrez, Antonio; Arregui, Gregorio; Núñez, Isabel; Sacchetti, Antonio

2015-01-01

To evaluate the influence of (11)C-choline PET/CT on radiotherapy planning in prostate cancer patients. Precise information on the extension of prostate cancer is crucial for the choice of an appropriate therapeutic strategy. (11)C-choline positron emission tomography ((11)C-choline PET/CT) has two roles in radiation oncology (RT): (1) patient selection for treatment and (2) target volume selection and delineation. In conjunction with high-accuracy techniques, it might offer an opportunity of dose escalation and better tumour control while sparing healthy tissues. We carried out a retrospective study in order to analyse RT planning modification based on (11)C-choline PET/CT in 16 prostate cancer patients. Patients were treated with hypofractionated step-and-shoot Intensity Modulated Radiotherapy (IMRT), or Volumetric Modulated Arc Therapy (VMAT), and a daily cone-beam CT for Image Guided Radiation Therapy (IGRT). All patients underwent a (11)C-choline-PET/CT scan prior to radiotherapy. In 37.5% of cases, a re-delineation and new dose prescription occurred. Data show good preliminary clinical results in terms of biochemical control and toxicity. No gastrointestinal (GI)/genitourinary (GU) grade III toxicities were observed after a median follow-up of 9.5 months. In our experience, concerning the treatment of prostate cancer (PCa), (11)C-choline PET/CT may be helpful in radiotherapy planning, either for dose escalation or exclusion of selected sites.

The Confluence of Stereotactic Ablative Radiotherapy and Tumor Immunology

PubMed Central

Finkelstein, Steven Eric; Timmerman, Robert; McBride, William H.; Schaue, Dörthe; Hoffe, Sarah E.; Mantz, Constantine A.; Wilson, George D.

2011-01-01

Stereotactic radiation approaches are gaining more popularity for the treatment of intracranial as well as extracranial tumors in organs such as the liver and lung. Technology, rather than biology, is driving the rapid adoption of stereotactic body radiation therapy (SBRT), also known as stereotactic ablative radiotherapy (SABR), in the clinic due to advances in precise positioning and targeting. Dramatic improvements in tumor control have been demonstrated; however, our knowledge of normal tissue biology response mechanisms to large fraction sizes is lacking. Herein, we will discuss how SABR can induce cellular expression of MHC I, adhesion molecules, costimulatory molecules, heat shock proteins, inflammatory mediators, immunomodulatory cytokines, and death receptors to enhance antitumor immune responses. PMID:22162711

Technical aspects of real time positron emission tracking for gated radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chamberland, Marc; Xu, Tong, E-mail: txu@physics.carleton.ca; McEwen, Malcolm R.

2016-02-15

Purpose: Respiratory motion can lead to treatment errors in the delivery of radiotherapy treatments. Respiratory gating can assist in better conforming the beam delivery to the target volume. We present a study of the technical aspects of a real time positron emission tracking system for potential use in gated radiotherapy. Methods: The tracking system, called PeTrack, uses implanted positron emission markers and position sensitive gamma ray detectors to track breathing motion in real time. PeTrack uses an expectation–maximization algorithm to track the motion of fiducial markers. A normalized least mean squares adaptive filter predicts the location of the markers amore » short time ahead to account for system response latency. The precision and data collection efficiency of a prototype PeTrack system were measured under conditions simulating gated radiotherapy. The lung insert of a thorax phantom was translated in the inferior–superior direction with regular sinusoidal motion and simulated patient breathing motion (maximum amplitude of motion ±10 mm, period 4 s). The system tracked the motion of a {sup 22}Na fiducial marker (0.34 MBq) embedded in the lung insert every 0.2 s. The position of the was marker was predicted 0.2 s ahead. For sinusoidal motion, the equation used to model the motion was fitted to the data. The precision of the tracking was estimated as the standard deviation of the residuals. Software was also developed to communicate with a Linac and toggle beam delivery. In a separate experiment involving a Linac, 500 monitor units of radiation were delivered to the phantom with a 3 × 3 cm photon beam and with 6 and 10 MV accelerating potential. Radiochromic films were inserted in the phantom to measure spatial dose distribution. In this experiment, the period of motion was set to 60 s to account for beam turn-on latency. The beam was turned off when the marker moved outside of a 5-mm gating window. Results: The precision of the tracking in the IS direction was 0.53 mm for a sinusoidally moving target, with an average count rate ∼250 cps. The average prediction error was 1.1 ± 0.6 mm when the marker moved according to irregular patient breathing motion. Across all beam deliveries during the radiochromic film measurements, the average prediction error was 0.8 ± 0.5 mm. The maximum error was 2.5 mm and the 95th percentile error was 1.5 mm. Clear improvement of the dose distribution was observed between gated and nongated deliveries. The full-width at halfmaximum of the dose profiles of gated deliveries differed by 3 mm or less than the static reference dose distribution. Monitoring of the beam on/off times showed synchronization with the location of the marker within the latency of the system. Conclusions: PeTrack can track the motion of internal fiducial positron emission markers with submillimeter precision. The system can be used to gate the delivery of a Linac beam based on the position of a moving fiducial marker. This highlights the potential of the system for use in respiratory-gated radiotherapy.« less

Multidisciplinary lung cancer meetings: improving the practice of radiation oncology and facing future challenges.

PubMed

Campbell, Belinda A; Ball, David; Mornex, Françoise

2015-02-01

Clinical guidelines widely recognize the importance of multidisciplinary meetings (MDM) in the optimal care of lung cancer patients. The published literature suggest that dedicated Lung Cancer MDM lead to increased treatment utilization rates and improved survival outcomes for patients with lung cancer. For radiation oncologists, Lung Cancer MDM have been proven to support evidence-based practice and improve the utilization of radiotherapy. Lung Cancer MDM also allow for education and promotion of specialty radiotherapy services. The fast pace of modern medicine is also presenting new challenges for the multidisciplinary lung cancer team, and technological advances are likely to lead to new changes in the structure of traditional Lung Cancer MDM. © 2015 Asian Pacific Society of Respirology.

High-precision dosimetry for radiotherapy using the optically stimulated luminescence technique and thin Al2O3:C dosimeters.

PubMed

Yukihara, E G; Yoshimura, E M; Lindstrom, T D; Ahmad, S; Taylor, K K; Mardirossian, G

2005-12-07

The potential of using the optically stimulated luminescence (OSL) technique with aluminium oxide (Al(2)O(3):C) dosimeters for a precise and accurate estimation of absorbed doses delivered by high-energy photon beams was investigated. This study demonstrates the high reproducibility of the OSL measurements and presents a preliminary determination of the depth-dose curve in water for a 6 MV photon beam from a linear accelerator. The uncertainty of a single OSL measurement, estimated from the variance of a large sample of dosimeters irradiated with the same dose, was 0.7%. In the depth-dose curve obtained using the OSL technique, the difference between the measured and expected doses was < or =0.7% for depths between 1.5 and 10 cm, and 1.1% for a depth of 15 cm. The readout procedure includes a normalization of the response of the dosimeter with respect to a reference dose in order to eliminate variations in the dosimeter mass, dosimeter sensitivity, and the reader's sensitivity. This may be relevant for quality assurance programmes, since it simplifies the requirements in terms of personnel training to achieve the precision and accuracy necessary for radiotherapy applications. We concluded that the OSL technique has the potential to be reliably incorporated in quality assurance programmes and dose verification.

Cost-effectiveness of modern radiotherapy techniques in locally advanced pancreatic cancer.

PubMed

Murphy, James D; Chang, Daniel T; Abelson, Jon; Daly, Megan E; Yeung, Heidi N; Nelson, Lorene M; Koong, Albert C

2012-02-15

Radiotherapy may improve the outcome of patients with pancreatic cancer but at an increased cost. In this study, the authors evaluated the cost-effectiveness of modern radiotherapy techniques in the treatment of locally advanced pancreatic cancer. A Markov decision-analytic model was constructed to compare the cost-effectiveness of 4 treatment regimens: gemcitabine alone, gemcitabine plus conventional radiotherapy, gemcitabine plus intensity-modulated radiotherapy (IMRT); and gemcitabine with stereotactic body radiotherapy (SBRT). Patients transitioned between the following 5 health states: stable disease, local progression, distant failure, local and distant failure, and death. Health utility tolls were assessed for radiotherapy and chemotherapy treatments and for radiation toxicity. SBRT increased life expectancy by 0.20 quality-adjusted life years (QALY) at an increased cost of $13,700 compared with gemcitabine alone (incremental cost-effectiveness ratio [ICER] = $69,500 per QALY). SBRT was more effective and less costly than conventional radiotherapy and IMRT. An analysis that excluded SBRT demonstrated that conventional radiotherapy had an ICER of $126,800 per QALY compared with gemcitabine alone, and IMRT had an ICER of $1,584,100 per QALY compared with conventional radiotherapy. A probabilistic sensitivity analysis demonstrated that the probability of cost-effectiveness at a willingness to pay of $50,000 per QALY was 78% for gemcitabine alone, 21% for SBRT, 1.4% for conventional radiotherapy, and 0.01% for IMRT. At a willingness to pay of $200,000 per QALY, the probability of cost-effectiveness was 73% for SBRT, 20% for conventional radiotherapy, 7% for gemcitabine alone, and 0.7% for IMRT. The current results indicated that IMRT in locally advanced pancreatic cancer exceeds what society considers cost-effective. In contrast, combining gemcitabine with SBRT increased clinical effectiveness beyond that of gemcitabine alone at a cost potentially acceptable by today's standards. Copyright © 2011 American Cancer Society.

[Preliminary application of an improved Demons deformable registration algorithm in tumor radiotherapy].

PubMed

Zhou, Lu; Zhen, Xin; Lu, Wenting; Dou, Jianhong; Zhou, Linghong

2012-01-01

To validate the efficiency of an improved Demons deformable registration algorithm and evaluate its application in registration of the treatment image and the planning image in image-guided radiotherapy (IGRT). Based on Brox's gradient constancy assumption and Malis's efficient second-order minimization algorithm, a grey value gradient similarity term was added into the original energy function, and a formula was derived to calculate the update of transformation field. The limited Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) algorithm was used to optimize the energy function for automatic determination of the iteration number. The proposed algorithm was validated using mathematically deformed images, physically deformed phantom images and clinical tumor images. Compared with the original Additive Demons algorithm, the improved Demons algorithm achieved a higher precision and a faster convergence speed. Due to the influence of different scanning conditions in fractionated radiation, the density range of the treatment image and the planning image may be different. The improved Demons algorithm can achieve faster and more accurate radiotherapy.

Postoperative Radiotherapy Patterns of Care and Survival Implications for Medulloblastoma in Young Children.

PubMed

Kann, Benjamin H; Park, Henry S; Lester-Coll, Nataniel H; Yeboa, Debra N; Benitez, Viviana; Khan, Atif J; Bindra, Ranjit S; Marks, Asher M; Roberts, Kenneth B

2016-12-01

Postoperative radiotherapy to the craniospinal axis is standard-of-care for pediatric medulloblastoma but is associated with long-term morbidity, particularly in young children. With the advent of modern adjuvant chemotherapy strategies, postoperative radiotherapy deferral has gained acceptance in children younger than 3 years, although it remains controversial in older children. To analyze recent postoperative radiotherapy national treatment patterns and implications for overall survival in patients with medulloblastoma ages 3 to 8 years. Using the National Cancer Data Base, patients ages 3 to 8 years diagnosed as having histologically confirmed medulloblastoma in 2004 to 2012, without distant metastases, who underwent surgery and adjuvant chemotherapy with or without postoperative radiotherapy at facilities nationwide accredited by the Commission on Cancer were identified. Patients were designated as having "postoperative radiotherapy upfront" if they received radiotherapy within 90 days of surgery or "postoperative radiotherapy deferred" otherwise. Factors associated with postoperative radiotherapy deferral were identified using multivariable logistic regression. Overall survival (OS) was compared using Kaplan-Meier analysis with log-rank tests and multivariable Cox regression. Statistical tests were 2-sided. Postoperative radiotherapy utilization and overall survival. Among 816 patients, 123 (15.1%) had postoperative radiotherapy deferred, and 693 (84.9%) had postoperative radiotherapy upfront; 36.8% of 3-year-olds and 4.1% of 8-year-olds had postoperative radiotherapy deferred (P < .001). On multivariable logistic regression, variables associated with postoperative radiotherapy deferral were age (odds ratio [OR], 0.57 per year; 95% CI, 0.49-0.67 per year) and year of diagnosis (OR, 1.18 per year; 95% CI, 1.08-1.29 per year). On survival analysis, with median follow-up of 4.8 years, OS was improved for those receiving postoperative radiotherapy upfront vs postoperative radiotherapy deferred (5-year OS: 82.0% vs 63.4%; P < .001). On multivariable analysis, variables associated with poorer OS were postoperative radiotherapy deferral (hazards ratio [HR], 1.95; 95% CI, 1.15-3.31); stage M1-3 disease (HR, 1.86; 95% CI, 1.10-3.16), and low facility volume (HR, 1.75; 95% CI, 1.04-2.94). Our national database analysis reveals a higher-than-expected and increasing rate of postoperative radiotherapy deferral in children with medulloblastoma ages 3 to 8 years. The analysis suggests that postoperative radiotherapy deferral is associated with worse survival in this age group, even in the modern era of chemotherapy.

Clinical trial tests precision radiotherapy for recurrent prostate cancer | Center for Cancer Research

Cancer.gov

CCR investigators are leading a trial of stereotactic body radiation therapy (SBRT) to treat localized prostate cancer that has recurred after standard radiation therapy. The technique uses advanced molecular imaging to guide the delivery of high doses of radiation just to tumors that have recurred, potentially leading to fewer side effects. Read more…

The cost-effectiveness of temozolomide in the adjuvant treatment of newly diagnosed glioblastoma in the United States

PubMed Central

Messali, Andrew; Hay, Joel W.; Villacorta, Reginald

2013-01-01

Background The objective of this work was to determine the cost-effectiveness of temozolomide compared with that of radiotherapy alone in the adjuvant treatment of newly diagnosed glioblastoma. Temozolomide is the only chemotherapeutic agent to have demonstrated a significant survival benefit in a randomized clinical trial. Our analysis builds on earlier work by incorporating caregiver time costs and generic temozolomide availability. It is also the first analysis applicable to the US context. Methods A systematic literature review was conducted to collect relevant data. Transition probabilities were calculated from randomized controlled trial data comparing temozolomide plus radiotherapy with radiotherapy alone. Direct costs were calculated from charges reported by the Mayo Clinic. Utilities were obtained from a previous cost-utility analysis. Using these data, a Markov model with a 1-month cycle length and 5-year time horizon was constructed. Results The addition of brand Temodar and generic temozolomide to the standard radiotherapy regimen was associated with base-case incremental cost-effectiveness ratios of $102 364 and $8875, respectively, per quality-adjusted life-year. The model was most sensitive to the progression-free survival associated with the use of only radiotherapy. Conclusions Both the brand and generic base-case estimates are cost-effective under a willingness-to-pay threshold of $150 000 per quality-adjusted life-year. All 1-way sensitivity analyses produced incremental cost-effectiveness ratios below this threshold. We conclude that both the brand Temodar and generic temozolomide are cost-effective treatments for newly diagnosed glioblastoma within the US context. However, assuming that the generic product produces equivalent quality of life and survival benefits, it would be significantly more cost-effective than the brand option. PMID:23935155

Basic immunology of antibody targeted radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong, Jeffrey Y.C.

2006-10-01

Antibody targeted radiotherapy brings an important new treatment modality to Radiation oncology clinic. Radiation dose to tumor and normal tissues are determined by a complex interplay of antibody, antigen, tumor, radionuclide, and host-related factors. A basic understanding of these immunologic and physiologic factors is important to optimally utilize this therapy in the clinic. Preclinical and clinical studies need to be continued to broaden our understanding and to develop new strategies to further improve the efficacy of this promising form of targeted therapy.

Dedicated magnetic resonance imaging in the radiotherapy clinic.

PubMed

Karlsson, Mikael; Karlsson, Magnus G; Nyholm, Tufve; Amies, Christopher; Zackrisson, Björn

2009-06-01

To introduce a novel technology arrangement in an integrated environment and outline the logistics model needed to incorporate dedicated magnetic resonance (MR) imaging in the radiotherapy workflow. An initial attempt was made to analyze the value and feasibility of MR-only imaging compared to computed tomography (CT) imaging, testing the assumption that MR is a better choice for target and healthy tissue delineation in radiotherapy. A 1.5-T MR unit with a 70-cm-bore size was installed close to a linear accelerator, and a special trolley was developed for transporting patients who were fixated in advance between the MR unit and the accelerator. New MR-based workflow procedures were developed and evaluated. MR-only treatment planning has been facilitated, thus avoiding all registration errors between CT and MR scans, but several new aspects of MR imaging must be considered. Electron density information must be obtained by other methods. Generation of digitally reconstructed radiographs (DRR) for x-ray setup verification is not straight forward, and reliable corrections of geometrical distortions must be applied. The feasibility of MR imaging virtual simulation has been demonstrated, but a key challenge to overcome is correct determination of the skeleton, which is often needed for the traditional approach of beam modeling. The trolley solution allows for a highly precise setup for soft tissue tumors without the invasive handling of radiopaque markers. The new logistics model with an integrated MR unit is efficient and will allow for improved tumor definition and geometrical precision without a significant loss of dosimetric accuracy. The most significant development needed is improved bone imaging.

Phase I clinical study of personalized peptide vaccination combined with radiotherapy for advanced hepatocellular carcinoma

PubMed Central

Shen, Jie; Wang, Li-Feng; Zou, Zheng-Yun; Kong, Wei-Wei; Yan, Jing; Meng, Fan-Yan; Chen, Fang-Jun; Du, Juan; Shao, Jie; Xu, Qiu-Ping; Ren, Hao-Zhen; Li, Ru-Tian; Wei, Jia; Qian, Xiao-Ping; Liu, Bao-Rui

2017-01-01

AIM To assess the efficacy and safety of a new treatment modality, cellular immune therapy based on personalized peptide vaccination (PPV-DC-CTL) combined with radiotherapy, for treating advanced hepatocellular carcinoma (HCC). METHODS A total of nine patients with advanced HCC were enrolled. Multidisciplinary consultation confirmed that all the patients definitely had no opportunity of surgery, because four patients had multiple liver metastases (the number of liver lesions > 3), one patient had liver metastases and portal vein tumor thrombosis, one patient had lung and bone metastases, two patients had liver and lung metastases and one patient had liver metastasis and peritoneal metastasis. Patients with metastasis were treated with precise radiotherapy combined with PPV-DC-CTL. RESULTS Following radiotherapy and one to three cycles of PPV-DC-CTL treatment, AFP levels were significantly decreased in six patients and imaging assessment of the lesions showed a partial response (PR) in three patients and stable disease in the other three patients. The response rate was 33% and disease control rate was 66%. This regimen was found to be safe and well tolerated. None of the patients developed liver or kidney side effects. Only one patient developed grade II bone marrow suppression and the remaining patients had no significant hematological side effects. CONCLUSION Radiotherapy combined with PPV-DC-CTL provides a new therapeutic strategy for patients with advanced HCC, which is well tolerated, safe, feasible and effective. PMID:28839440

Cytopathologic evaluation of patients submitted to radiotherapy for uterine cervix cancer.

PubMed

Padilha, Cátia Martins Leite; Araújo, Mário Lúcio Cordeiro; Souza, Sergio Augusto Lopes de

2017-04-01

Cervical cancer is an important public health problem. Pap smear is the leading strategy of screening programs for cervical cancer worldwide. However, delayed diagnosis leads to more aggressive and less effective treatments. Patients with uterine cervix malignancies who are referred for radiotherapy have advanced-stage disease, which results in high rates of locoregional recurrence. The use of radiotherapy as a treatment for cervical cancer causes morphological changes in neoplastic and non-neoplastic epithelial cells, as well as in stromal cells, which make it difficult to diagnose the residual lesion, resulting in a dilemma in cytopathological routine. Based on the difficulties of cytopathologic evaluation for the follow-up of patients treated with radiotherapy for cervical cancer, our objective was to describe the actinic cytopathic effects. Our paper was based on a structured review including the period from June 2015 to April 2016, aiming at an exploratory-descriptive study. Bibliographic investigations were carried out through selection and analysis of articles, list of authors and keywords, selection of new articles focused on the analysis of bibliographic references to previously selected documents, as well as textbooks of recognized merit. The most incident actinic cytopathological alterations as described in the literature are: cellular gigantism, nuclear and cytoplasmic vacuolization, dyskeratosis, bi- and multinucleated (B/M) cells, macro and multiple nucleoli, anisokaryosis, anisonucleolosis and nuclear pyknosis. To date, a protocol has not been established that can precisely differentiate the morphological characteristics between benign cells with actinic effects from recurrent malignant cells on post-radiotherapy smears.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edmunds, D; Donovan, E

Purpose: To determine whether the Microsoft Kinect Version 2 (Kinect v2), a commercial off-the-shelf (COTS) depth sensors designed for entertainment purposes, were robust to the radiotherapy treatment environment and could be suitable for monitoring of voluntary breath-hold compliance. This could complement current visual monitoring techniques, and be useful for heart sparing left breast radiotherapy. Methods: In-house software to control Kinect v2 sensors, and capture output information, was developed using the free Microsoft software development kit, and the Cinder creative coding C++ library. Each sensor was used with a 12m USB 3.0 active cable. A solid water block was used asmore » the object. The depth accuracy and precision of the sensors was evaluated by comparing Kinect reported distance to the object with a precision laser measurement across a distance range of 0.6m to 2.0 m. The object was positioned on a high-precision programmable motion platform and moved in two programmed motion patterns and Kinect reported distance logged. Robustness to the radiation environment was tested by repeating all measurements with a linear accelerator operating over a range of pulse repetition frequencies (6Hz to 400Hz) and dose rates 50 to 1500 monitor units (MU) per minute. Results: The complex, consistent relationship between true and measured distance was unaffected by the radiation environment, as was the ability to detect motion. Sensor precision was < 1 mm and the accuracy between 1.3 mm and 1.8 mm when a distance correction was applied. Both motion patterns were tracked successfully with a root mean squared error (RMSE) of 1.4 and 1.1 mm respectively. Conclusion: Kinect v2 sensors are capable of tracking pre-programmed motion patterns with an accuracy <2 mm and appear robust to the radiotherapy treatment environment. A clinical trial using Kinect v2 sensor for monitoring voluntary breath hold has ethical approval and is open to recruitment. The authors are supported by a National Institute of Health Research (NIHR) Career Development Fellowship (CDF-2013-06-005). Microsoft Corporation donated three sensors. The views expressed in this publication are those of the author(s) and not necessarily those of the NHS, the National Institute for Health Research or the Department of Health.« less

Characterizing a pulse-resolved dosimetry system for complex radiotherapy beams using organic scintillators.

PubMed

Beierholm, Anders R; Ottosson, Rickard O; Lindvold, Lars R; Behrens, Claus F; Andersen, Claus E

2011-05-21

A fast-readout dosimetry system based on fibre-coupled organic scintillators has been developed for the purpose of conducting point measurements of absorbed dose in radiotherapy beams involving high spatial and temporal dose gradients. The system measures the dose for each linac radiation pulse with millimetre spatial resolution. To demonstrate the applicability of the system in complex radiotherapy fields, output factors and per cent depth dose measurements were performed in solid water for a 6 MV photon beam and compared with Monte Carlo simulated doses for square fields down to 0.6 cm × 0.6 cm size. No significant differences between measurements and simulations were observed. The temporal resolution of the system was demonstrated by measuring dose per pulse, beam start-up transients and the quality factor for 6 MV. The precision of dose per pulse measurements was within 2.7% (1 SD) for a 10 cm × 10 cm field at 10 cm depth. The dose per pulse behaviour compared well with linac target current measurements and accumulated dose measurements, and the system was able to resolve transient dose delivery differences between two Varian linac builds. The system therefore shows promise for reference dosimetry and quality assurance of complex radiotherapy treatments.

Accurate respiration measurement using DC-coupled continuous-wave radar sensor for motion-adaptive cancer radiotherapy.

PubMed

Gu, Changzhan; Li, Ruijiang; Zhang, Hualiang; Fung, Albert Y C; Torres, Carlos; Jiang, Steve B; Li, Changzhi

2012-11-01

Accurate respiration measurement is crucial in motion-adaptive cancer radiotherapy. Conventional methods for respiration measurement are undesirable because they are either invasive to the patient or do not have sufficient accuracy. In addition, measurement of external respiration signal based on conventional approaches requires close patient contact to the physical device which often causes patient discomfort and undesirable motion during radiation dose delivery. In this paper, a dc-coupled continuous-wave radar sensor was presented to provide a noncontact and noninvasive approach for respiration measurement. The radar sensor was designed with dc-coupled adaptive tuning architectures that include RF coarse-tuning and baseband fine-tuning, which allows the radar sensor to precisely measure movement with stationary moment and always work with the maximum dynamic range. The accuracy of respiration measurement with the proposed radar sensor was experimentally evaluated using a physical phantom, human subject, and moving plate in a radiotherapy environment. It was shown that respiration measurement with radar sensor while the radiation beam is on is feasible and the measurement has a submillimeter accuracy when compared with a commercial respiration monitoring system which requires patient contact. The proposed radar sensor provides accurate, noninvasive, and noncontact respiration measurement and therefore has a great potential in motion-adaptive radiotherapy.

Factors Influencing Neurocognitive Outcomes in Young Patients With Benign and Low-Grade Brain Tumors Treated With Stereotactic Conformal Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jalali, Rakesh, E-mail: rjalali@tmc.gov.i; Mallick, Indranil; Dutta, Debnarayan

2010-07-15

Purpose: To present the effect of radiotherapy doses to different volumes of normal structures on neurocognitive outcomes in young patients with benign and low-grade brain tumors treated prospectively with stereotactic conformal radiotherapy (SCRT). Methods and Materials: Twenty-eight patients (median age, 13 years) with residual/progressive brain tumors (10 craniopharyngioma, 8 cerebellar astrocytoma, 6 optic pathway glioma and 4 cerebral low-grade glioma) were treated with SCRT to a dose of 54 Gy in 30 fractions over 6 weeks. Prospective neuropsychological assessments were done at baseline before RT and at subsequent follow-up examinations. The change in intelligence quotient (IQ) scores was correlated withmore » various factors, including dose-volume to normal structures. Results: Although the overall mean full-scale IQ (FSIQ) at baseline before RT remained unchanged at 2-year follow-up after SCRT, one third of patients did show a >10% decline in FSIQ as compared with baseline. Logistic regression analysis demonstrated that patients aged <15 years had a significantly higher chance of developing a >10% drop in FSIQ than older patients (53% vs. 10%, p = 0.03). Dosimetric comparison in patients showing a >10% decline vs. patients showing a <10% decline in IQ revealed that patients receiving >43.2 Gy to >13% of volume of the left temporal lobe were the ones to show a significant drop in FSIQ (p = 0.048). Radiotherapy doses to other normal structures, including supratentorial brain, right temporal lobe, and frontal lobes, did not reveal any significant correlation. Conclusion: Our prospectively collected dosimetric data show younger age and radiotherapy doses to left temporal lobe to be predictors of neurocognitive decline, and may well be used as possible dose constraints for high-precision radiotherapy planning.« less

National trends in the recommendation of radiotherapy after prostatectomy for prostate cancer before and after the reporting of a survival benefit in March 2009.

PubMed

Mahal, Brandon A; Hoffman, Karen E; Efstathiou, Jason A; Nguyen, Paul L

2015-06-01

Three randomized trials demonstrated that postprostatectomy adjuvant radiotherapy improves biochemical disease-free survival for patients with adverse pathologic features, and 1 trial found adjuvant radiotherapy improves overall survival. We sought to determine whether postprostatectomy radiotherapy (PPRT) utilization changed after publication of the survival benefit in March 2009. The Surveillance, Epidemiology, and End Results database was used to identify men diagnosed with prostate cancer from 2004 to 2011 who met criteria for enrollment in the randomized trials (positive margins and/or pT3-4 disease at radical prostatectomy). Joinpoint regression identified inflection points in PPRT utilization. Logistic regression was used to evaluate factors associated with PPRT recommendation. Of 35,361 men, 5104 (14.4%) received a recommendation for PPRT. In joinpoint regression, 2009 was the inflection point in PPRT utilization. In multivariable analysis, PPRT recommendations were more likely after March 2009 than before 15.8% vs. 13.5%, adjusted odds ratio (AOR; 1.09; 95% confidence interval [CI], 1.02-1.16; P = .008), in men with pT3 (vs. pT2, AOR, 2.81; 95% CI, 2.53-3.11; P < .001), pT4 (vs. pT2 AOR, 4.62; 95% CI, 3.85-5.54; P < .001), or margin positive (AOR, 1.46; 95% CI, 1.34-1.58; P < .001) disease and in men who were younger (per year decrease, AOR, 1.02; 95% CI, 1.02-1.03; P < .001), married (AOR, 1.10; 95% CI, 1.02-1.19; P = .01), or lived in metropolitan areas (AOR, 1.30; 95% CI, 1.16-1.47; P < .001). PPRT recommendations increased after the reporting of a survival benefit in March 2009, but absolute utilization rates remain low, suggesting that the oncologic community remains unconvinced that PPRT is needed for most patients with adverse features. Further work is needed to identify patients who might benefit most from PPRT. Copyright © 2015 Elsevier Inc. All rights reserved.

PREFACE: Third International Conference on Radiotherapy Gel Dosimetry

NASA Astrophysics Data System (ADS)

DeDeene, Yves; Baldock, Clive

2004-01-01

Gel dosimetry is not merely another dosimetry technique. Gel dosimeters are integrating dosimeters that enable dose verification in three dimensions. The application of a 3D dosimetry technique in the clinic would give a real push to the implementation of advanced high-precision radiotherapy technologies in many institutes. It can be expected that with the recent developments in the field towards more user-friendly gel systems and imaging modalities, gel dosimetry will become a vital link in the chain of high-precision radiation cancer therapy in the near future. Many researchers all over the world have contributed to the emerging technology of gel dosimetry. The research field of gel dosimetry is recognized to be very broad from polymer and analytical chemistry and material research to imaging technologies. The DOSGEL conferences in the past have proven to be an important forum at which material scientists, chemists, medical physicists, magnetic resonance imaging and radiation specialists brought together a critical mass of thoughts, findings and considerations. DOSGEL 2004 has been endorsed by many international, supra-national and national medical physics organizations and publishers. These proceedings contain 51 papers that cover various aspects of gel dosimetry.

Adjuvant Chemoradiation for Gastric Cancer Using Epirubicin, Cisplatin, and 5-Fluorouracil Before and After Three-Dimensional Conformal Radiotherapy With Concurrent Infusional 5-Fluorouracil: A Multicenter Study of the Trans-Tasman Radiation Oncology Group

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leong, Trevor, E-mail: trevor.leong@petermac.or; Joon, Daryl Lim; Willis, David

Purpose: The INT0116 study has established postoperative chemoradiotherapy as the standard of care for completely resected gastric adenocarcinoma. However, the optimal chemoradiation regimen remains to be defined. We conducted a prospective, multicenter study to evaluate an alternative chemoradiation regimen that combines more current systemic treatment with modern techniques of radiotherapy delivery. Methods and Materials: Patients with adenocarcinoma of the stomach who had undergone an R0 resection were eligible. Adjuvant therapy consisted of one cycle of epirubicin, cisplatin, and 5-FU (ECF), followed by radiotherapy with concurrent infusional 5-FU, and then two additional cycles of ECF. Radiotherapy was delivered using precisely defined,more » multiple-field, three-dimensional conformal techniques. Results: A total of 54 assessable patients were enrolled from 19 institutions. The proportion of patients commencing Cycles 1, 2, and 3 of ECF chemotherapy were 100%, 81%, and 67% respectively. In all, 94% of patients who received radiotherapy completed treatment as planned. Grade 3/4 neutropenia occurred in 66% of patients with 7.4% developing febrile neutropenia. Most neutropenic episodes (83%) occurred in the post-radiotherapy period during cycles 2 and 3 of ECF. Grade 3/4 gastrointestinal toxicity occurred in 28% of patients. In all, 35% of radiotherapy treatment plans contained protocol deviations that were satisfactorily amended before commencement of treatment. At median follow-up of 36 months, the 3-year overall survival rate was estimated at 61.6%. Conclusions: This adjuvant regimen using ECF before and after three-dimensional conformal chemoradiation is feasible and can be safely delivered in a cooperative group setting. A regimen similar to this is currently being compared with the INT0116 regimen in a National Cancer Institute-sponsored, randomized Phase III trial.« less

Clinical and dosimetric implications of intensity-modulated radiotherapy for early-stage glottic carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, Matthew Christopher, E-mail: wardm3@ccf.org; Pham, Yvonne D.; Kotecha, Rupesh

2016-04-01

Conventional parallel-opposed radiotherapy (PORT) is the established standard technique for early-stage glottic carcinoma. However, case reports have reported the utility of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) with or without image guidance (image-guided radiotherapy, IGRT) in select patients. The proposed advantages of IMRT/VMAT include sparing of the carotid artery, thyroid gland, and the remaining functional larynx, although these benefits remain unclear. The following case study presents a patient with multiple vascular comorbidities treated with VMAT for early-stage glottic carcinoma. A detailed explanation of the corresponding treatment details, dose-volume histogram (DVH) analysis, and a review of the relevant literaturemore » are provided. Conventional PORT remains the standard of care for early-stage glottic carcinoma. IMRT or VMAT may be beneficial for select patients, although great care is necessary to avoid a geographical miss. Clinical data supporting the benefit of CRT are lacking. Therefore, these techniques should be used with caution and only in selected patients.« less

The population benefit of evidence-based radiotherapy: 5-Year local control and overall survival benefits.

PubMed

Hanna, T P; Shafiq, J; Delaney, G P; Vinod, S K; Thompson, S R; Barton, M B

2018-02-01

To describe the population benefit of radiotherapy in a high-income setting if evidence-based guidelines were routinely followed. Australian decision tree models were utilized. Radiotherapy alone (RT) benefit was defined as the absolute proportional benefit of radiotherapy compared with no treatment for radical indications, and of radiotherapy over surgery alone for adjuvant indications. Chemoradiotherapy (CRT) benefit was the absolute incremental benefit of concurrent chemoradiotherapy over RT. Five-year local control (LC) and overall survival (OS) benefits were measured. Citation databases were systematically queried for benefit data. Meta-analysis and sensitivity analysis were performed. 48% of all cancer patients have indications for radiotherapy, 34% curative and 14% palliative. RT provides 5-year LC benefit in 10.4% of all cancer patients (95% Confidence Interval 9.3, 11.8) and 5-year OS benefit in 2.4% (2.1, 2.7). CRT provides 5-year LC benefit in an additional 0.6% of all cancer patients (0.5, 0.6), and 5-year OS benefit for an additional 0.3% (0.2, 0.4). RT benefit was greatest for head and neck (LC 32%, OS 16%), and cervix (LC 33%, OS 18%). CRT LC benefit was greatest for rectum (6%) and OS for cervix (3%) and brain (3%). Sensitivity analysis confirmed a robust model. Radiotherapy provides significant 5-year LC and OS benefits as part of evidence-based cancer care. CRT provides modest additional benefits. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Determining the minimal clinically important difference criteria for the Multidimensional Fatigue Inventory in a radiotherapy population.

PubMed

Purcell, Amanda; Fleming, Jennifer; Bennett, Sally; Burmeister, Bryan; Haines, Terry

2010-03-01

The Multidimensional Fatigue Inventory (MFI) is a commonly used cancer-related fatigue assessment tool. Unlike other fatigue assessments, there are no published minimal clinically important difference (MCID) criteria for the MFI in cancer populations. MCID criteria determine the smallest change in scores that can be regarded as important, allowing clinicians and researchers to interpret the meaning of changes in patient's fatigue scores. This research aims to improve the clinical utility of the MFI by establishing MCID criteria for the MFI sub-scales in a radiotherapy population. Two hundred ten patients undergoing radiotherapy were recruited to a single-centre prospective cohort study. Patients were assessed at three time points, at the start of radiotherapy, the end of radiotherapy and 6 weeks after radiotherapy completion. Assessment consisted of four clinically relevant constructs: (1) treatment impact on fatigue, (2) health-related quality of life, (3) performance status and (4) occupational productivity. These constructs were used as external or anchor-based measures to determine MCIDs for each sub-scale of the MFI. Multiple MCIDs were identified, each from a different perspective based on the constructs cited. Researchers seeking to use a generic MCID may wish to use a two-point reference for each MFI sub-scale as it was consistent across the pre- and post-radiotherapy comparison and occupational productivity anchors. MCIDs validated in this study allow better interpretation of changes in MFI sub-scale scores and allow effect size calculations for determining sample size in future studies.

Radiotherapy infrastructure and human resources in Switzerland : Present status and projected computations for 2020.

PubMed

Datta, Niloy Ranjan; Khan, Shaka; Marder, Dietmar; Zwahlen, Daniel; Bodis, Stephan

2016-09-01

The purpose of this study was to evaluate the present status of radiotherapy infrastructure and human resources in Switzerland and compute projections for 2020. The European Society of Therapeutic Radiation Oncology "Quantification of Radiation Therapy Infrastructure and Staffing" guidelines (ESTRO-QUARTS) and those of the International Atomic Energy Agency (IAEA) were applied to estimate the requirements for teleradiotherapy (TRT) units, radiation oncologists (RO), medical physicists (MP) and radiotherapy technologists (RTT). The databases used for computation of the present gap and additional requirements are (a) Global Cancer Incidence, Mortality and Prevalence (GLOBOCAN) for cancer incidence (b) the Directory of Radiotherapy Centres (DIRAC) of the IAEA for existing TRT units (c) human resources from the recent ESTRO "Health Economics in Radiation Oncology" (HERO) survey and (d) radiotherapy utilization (RTU) rates for each tumour site, published by the Ingham Institute for Applied Medical Research (IIAMR). In 2015, 30,999 of 45,903 cancer patients would have required radiotherapy. By 2020, this will have increased to 34,041 of 50,427 cancer patients. Switzerland presently has an adequate number of TRTs, but a deficit of 57 ROs, 14 MPs and 36 RTTs. By 2020, an additional 7 TRTs, 72 ROs, 22 MPs and 66 RTTs will be required. In addition, a realistic dynamic model for calculation of staff requirements due to anticipated changes in future radiotherapy practices has been proposed. This model could be tailor-made and individualized for any radiotherapy centre. A 9.8 % increase in radiotherapy requirements is expected for cancer patients over the next 5 years. The present study should assist the stakeholders and health planners in designing an appropriate strategy for meeting future radiotherapy needs for Switzerland.

Intra-fraction motion of larynx radiotherapy

NASA Astrophysics Data System (ADS)

Durmus, Ismail Faruk; Tas, Bora

2018-02-01

In early stage laryngeal radiotherapy, movement is an important factor. Thyroid cartilage can move from swallowing, breathing, sound and reflexes. The effects of this motion on the target volume (PTV) during treatment were examined. In our study, the target volume movement during the treatment for this purpose was examined. Thus, setup margins are re-evaluated and patient-based PTV margins are determined. Intrafraction CBCT was scanned in 246 fractions for 14 patients. During the treatment, the amount of deviation which could be lateral, vertical and longitudinal axis was determined. ≤ ± 0.1cm deviation; 237 fractions in the lateral direction, 202 fractions in the longitudinal direction, 185 fractions in the vertical direction. The maximum deviation values were found in the longitudinal direction. Intrafraction guide in laryngeal radiotherapy; we are sure of the correctness of the treatment, the target volume is to adjust the margin and dose more precisely, we control the maximum deviation of the target volume for each fraction. Although the image quality of intrafraction-CBCT scans was lower than the image quality of planning CT, they showed sufficient contrast for this work.

Targeted nanoparticles for tumour radiotherapy enhancement—the long dawn of a golden era?

PubMed Central

Gargioni, Elisabetta; Schulz, Florian; Raabe, Annette; Burdak-Rothkamm, Susanne; Rieckmann, Thorsten

2016-01-01

Despite considerable progress in (I) our understanding of the aetiopathology of head and neck cancer and (II) the precise delivery of radiotherapy, long-term survival rates for many patients with head and neck cancer remain disappointingly low. Over the past years, gold nanoparticles (NP) have emerged as promising radiation dose enhancers. In a recent study published in Nanoscale, Popovtzer et al. have used gold NP coated with an antibody against the epidermal growth factor receptor (EGFR) in an attempt to enhance radiation-induced tumour cell killing in a head and neck cancer xenograft model. They report a significant impact of the combined treatment with radiation and gold NP on tumour growth and suggest an involvement of apoptosis, inhibition of angiogenesis and diminished tissue repair. In this perspective, we illustrate the underlying radiobiophysical concepts and discuss some of the challenges associated with this and related nanoparticle-radiotherapy studies from a physics, chemistry, biology and therapy angle. We conclude that strong interdisciplinary collaborations spanning all these areas are crucially important to proceed towards effective cancer treatment with gold NP “from bench to bedside”. PMID:28151534

Recommendations of the Spanish Societies of Radiation Oncology (SEOR), Nuclear Medicine & Molecular Imaging (SEMNiM), and Medical Physics (SEFM) on (18)F-FDG PET-CT for radiotherapy treatment planning.

PubMed

Caballero Perea, Begoña; Villegas, Antonio Cabrera; Rodríguez, José Miguel Delgado; Velloso, María José García; Vicente, Ana María García; Cabrerizo, Carlos Huerga; López, Rosa Morera; Romasanta, Luis Alberto Pérez; Beltrán, Moisés Sáez

2012-01-01

Positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) is a valuable tool for diagnosing and staging malignant lesions. The fusion of PET and computed tomography (CT) yields images that contain both metabolic and morphological information, which, taken together, have improved the diagnostic precision of PET in oncology. The main imaging modality for planning radiotherapy treatment is CT. However, PET-CT is an emerging modality for use in planning treatments because it allows for more accurate treatment volume definition. The use of PET-CT for treatment planning is highly complex, and protocols and standards for its use are still being developed. It seems probable that PET-CT will eventually replace current CT-based planning methods, but this will require a full understanding of the relevant technical aspects of PET-CT planning. The aim of the present document is to review these technical aspects and to provide recommendations for clinical use of this imaging modality in the radiotherapy planning process.

Recommendations of the Spanish Societies of Radiation Oncology (SEOR), Nuclear Medicine & Molecular Imaging (SEMNiM), and Medical Physics (SEFM) on 18F-FDG PET-CT for radiotherapy treatment planning

PubMed Central

Caballero Perea, Begoña; Villegas, Antonio Cabrera; Rodríguez, José Miguel Delgado; Velloso, María José García; Vicente, Ana María García; Cabrerizo, Carlos Huerga; López, Rosa Morera; Romasanta, Luis Alberto Pérez; Beltrán, Moisés Sáez

2012-01-01

Positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) is a valuable tool for diagnosing and staging malignant lesions. The fusion of PET and computed tomography (CT) yields images that contain both metabolic and morphological information, which, taken together, have improved the diagnostic precision of PET in oncology. The main imaging modality for planning radiotherapy treatment is CT. However, PET-CT is an emerging modality for use in planning treatments because it allows for more accurate treatment volume definition. The use of PET-CT for treatment planning is highly complex, and protocols and standards for its use are still being developed. It seems probable that PET-CT will eventually replace current CT-based planning methods, but this will require a full understanding of the relevant technical aspects of PET-CT planning. The aim of the present document is to review these technical aspects and to provide recommendations for clinical use of this imaging modality in the radiotherapy planning process. PMID:24377032

Vrx: a verify-record system for radiotherapy.

PubMed

Dickof, P; Morris, P; Getz, D

1984-01-01

A system of computer programs has been created to allow the entry of radiotherapy treatment details as defined by the physician, the verification of the machine parameters at every treatment, and the recording of the entire course of treatment. Various utility programs are available to simplify the use and maintenance of the system. The majority of the code is written in FORTRAN-77, the remainder in MACRO-11. The system has been implemented on a PDP 11/60 minicomputer for use with a Mevatron linear accelerator, the implementation required minor hardware changes to the accelerator.

Phase I/II Trial Evaluating Carbon Ion Radiotherapy for Salvaging Treatment of Locally Recurrent Nasopharyngeal Carcinoma.

PubMed

Kong, Lin; Hu, Jiyi; Guan, Xiyin; Gao, Jing; Lu, Rong; Lu, Jiade J

2016-01-01

Radiation therapy is the mainstay strategy for the treatment of nasopharyngeal cancer (NPC). Intensity-modulated X-ray therapy (IMXT) alone is the current standard for stage I and II NPC. For stage III and IV A/B diseases, concurrent chemotherapy should be provided in addition to IMXT. However, optimal treatment for locally recurrent NPC after previous definitive dose of radiotherapy is lacking. Various techniques including brachytherapy, IMXT, stereotactic radiosurgery or radiotherapy (SRS or SBRT) have been used in the management of locally recurrent NPC. Due to the inherent limitation of these techniques, i.e., limited range of irradiation or over-irradiation to surrounding normal tissues, moderate efficacy has been observed at the cost of severe toxicities. Carbon ion radiotherapy (CIRT) offers potential physical and biological advantages over photon and proton radiotherapy. Due to the inverted dose profile of particle beams and their greater energy deposition within the Bragg peak, precise dose delivery to the target volume(s) without exposing the surrounding organs at risk to extra doses is possible. In addition, CIRT provides an increased relative biological effectiveness (RBE) as compared to photon and proton radiotherapy. Such advantages may translate to improved outcomes after irradiation in terms of disease control in radio-resistant and previously treated, recurrent malignancies. It is therefore reasonable to postulate that recurrent NPC after high-dose radiotherapy could be more resistant to re-irradiation using photons. Reports on the treatment of radio-resistant malignancies in the head and neck region such as melanoma, sarcoma, and adenoid cystic carcinoma (ACC) have demonstrated superior local control rates from CIRT as compared to photon irradiation. Thus patients with recurrent NPC are likely to benefit from the enhanced biological effectiveness of carbon ions. As effective retreatment strategy is lacking for locally recurrent NPC, carbon ion radiation therapy offers an ideal alternate to conventional X-ray irradiation. The recommended dose of re-irradiation using CIRT for locally recurrent NPC will be determined in the dose-escalating phase (Phase I) of the study. Efficacy in terms of local progression-free survival (LPFS) and overall survival (OS) will be studied in the second phase of the study. Increasing doses of CIRT using raster scanning technology from 55GyE (22×2.5 GyE) to 65 GyE (26× 2.5 GyE) will be delivered in the Phase I part of the study. The primary endpoint of the Phase I part of the study is acute and sub-acute toxicities; the primary endpoint in the Phase II part is local progression-free survival and overall survival. Using the historical 2-year OS rate of 50% in locally recurrent NPC patients treated with photon or proton, we hypothesize that CIRT can improve the 2-year OS rate to 70%. The utilization of conventional radiation techniques including IMXT, brachytherapy, or stereotactic radiation therapy provides moderate efficacy in the treatment of locally recurrent NPC due to the limitations in dose distribution and biological effectiveness. Improved outcome in terms of treatment-induced toxicity, LC, LPFS, and OS are expected using CIRT due to the physical and biological characteristics of carbon ion beam. However, the recommended dose of CIRT used in re-irradiation for the local NPC focus remain to be determined. The recommended dose as well as the efficacy of CIRT in the treatment of locally recurrent NPC will be evaluated in the present trial.

Risk-adaptive radiotherapy

NASA Astrophysics Data System (ADS)

Kim, Yusung

Currently, there is great interest in integrating biological information into intensity-modulated radiotherapy (IMRT) treatment planning with the aim of boosting high-risk tumor subvolumes. Selective boosting of tumor subvolumes can be accomplished without violating normal tissue complication constraints using information from functional imaging. In this work we have developed a risk-adaptive optimization-framework that utilizes a nonlinear biological objective function. Employing risk-adaptive radiotherapy for prostate cancer, it is possible to increase the equivalent uniform dose (EUD) by up to 35.4 Gy in tumor subvolumes having the highest risk classification without increasing normal tissue complications. Subsequently, we have studied the impact of functional imaging accuracy, and found on the one hand that loss in sensitivity had a large impact on expected local tumor control, which was maximal when a low-risk classification for the remaining low risk PTV was chosen. While on the other hand loss in specificity appeared to have a minimal impact on normal tissue sparing. Therefore, it appears that in order to improve the therapeutic ratio a functional imaging technique with a high sensitivity, rather than specificity, is needed. Last but not least a comparison study between selective boosting IMRT strategies and uniform-boosting IMRT strategies yielding the same EUD to the overall PTV was carried out, and found that selective boosting IMRT considerably improves expected TCP compared to uniform-boosting IMRT, especially when lack of control of the high-risk tumor subvolumes is the cause of expected therapy failure. Furthermore, while selective boosting IMRT, using physical dose-volume objectives, did yield similar rectal and bladder sparing when compared its equivalent uniform-boosting IMRT plan, risk-adaptive radiotherapy, utilizing biological objective functions, did yield a 5.3% reduction in NTCP for the rectum. Hence, in risk-adaptive radiotherapy the therapeutic ratio can be increased over that which can be achieved with conventional selective boosting IMRT using physical dose-volume objectives. In conclusion, a novel risk-adaptive radiotherapy strategy is proposed and promises increased expected local control for locoregionally advanced tumors with equivalent or better normal tissue sparing.

[Current status and potential perspectives in classical radiotherapy technology].

PubMed

Dabić-Stanković, Kata M; Stanković, Jovan B; Radosević-Jelić, Ljiljana M

2004-01-01

After purchase of radiotherapy equipment in 2003, classic radiation therapy in Serbia will reach the highest world level. In order to define the highest standards in radiation technology, we analyzed the current status and potential perspectives of radiation therapy. An analysis of present situation in the USA, assumed as the most developed in the world, was done. Available data, collected in the last 3 years (equipment assortment, therapy modalities, workload and manpower) for 284 radiotherapy centers, out of potential 2050, were analyzed. Results were presented as crude percentage and matched to point current status. The analysis showed that CLINAC accelerators are the most popular (82.7%), as well as, ADAC (43.7%) and Focus (CMS) (27.4%) systems for therapy planning. Movement towards virtual simulation is evident (59.3%), although classic "simulation" is not fully eliminated from the radiotherapy chain. The most popular brachytherapy afterloader is Microselectron HDR (71%). About 64.4% centers use IMPAC communication/verification/record system that seems more open than Varis. All centers practice modern radiotherapy modalities and techniques (CPRT, IMRT, SRS/SRT, TBI, IORT, IVBHRT, HDR BHRT, etc.). CT and MRI availability is out of question, but PET is available in 3% of centers, however this percentage is rapidly growing. Up to 350 new patients per year are treated by one accelerator (about 35 pts. a day). Centers are relatively small and utilize 2-3 accelerators on average. Average FTE staffing norm is 4 radiation oncologists, 2-3 medical radiotherapy physicists, about 3 certified medical dosimetrists and about 6 radiotherapy technologists. In the past 5 years relative stagnation in classic radiotherapy has been observed. In spite of substantial investments in technology and consequent improvements, as well as wide introduction of computers in radiotherapy, radiotherapy results have not changed significantly. Vendor developement strategies do not point that this trend will change in the next 5 years. On the other hand, wide introduction of the PET in each radiotherapy chain ring (diagnostics, planning, follow-up), could improve results (local and regional control, as well as quality of patients' life).

Dedicated Linac for Radioneurosurgery at the National Institute of Neurology and Neurosurgery of Mexico

NASA Astrophysics Data System (ADS)

Celis-López, Miguel A.; Lárraga-Gutiérrez, José M.

2003-09-01

The objective is to present a description and the main clinical applications of this dedicated Linac for benign and malignant tumors in the central nervous system. The Novalis (BrainLab, Germany) is a 6 MV dedicated linac for a single high dose Radiosurgery (RS) and for fractionated doses in Stereotactic Radiotherapy with a high level of precision at the isocenter.

A new methodological approach for PET implementation in radiotherapy treatment planning.

PubMed

Bellan, Elena; Ferretti, Alice; Capirci, Carlo; Grassetto, Gaia; Gava, Marcello; Chondrogiannis, Sotirios; Virdis, Graziella; Marzola, Maria Cristina; Massaro, Arianna; Rubello, Domenico; Nibale, Otello

2012-05-01

In this paper, a new methodological approach to using PET information in radiotherapy treatment planning has been discussed. Computed tomography (CT) represents the primary modality to plan personalized radiation treatment, because it provides the basic electron density map for correct dose calculation. If PET scanning is also performed it is typically coregistered with the CT study. This operation can be executed automatically by a hybrid PET/CT scanner or, if the PET and CT imaging sets have been acquired through different equipment, by a dedicated module of the radiotherapy treatment planning system. Both approaches have some disadvantages: in the first case, the bore of a PET/CT system generally used in clinical practice often does not allow the use of certain bulky devices for patient immobilization in radiotherapy, whereas in the second case the result could be affected by limitations in window/level visualization of two different image modalities, and the displayed PET volumes can appear not to be related to the actual uptake into the patient. To overcome these problems, at our centre a specific procedure has been studied and tested in 30 patients, allowing good results of precision in the target contouring to be obtained. The process consists of segmentation of the biological target volume by a dedicated PET/CT console and its export to a dedicated radiotherapy system, where an image registration between the CT images acquired by the PET/CT scanner and a large-bore CT is performed. The planning target volume is contoured only on the large-bore CT and is used for virtual simulation, to individuate permanent skin markers on the patient.

Evaluation of an automatic MR-based gold fiducial marker localisation method for MR-only prostate radiotherapy

NASA Astrophysics Data System (ADS)

Maspero, Matteo; van den Berg, Cornelis A. T.; Zijlstra, Frank; Sikkes, Gonda G.; de Boer, Hans C. J.; Meijer, Gert J.; Kerkmeijer, Linda G. W.; Viergever, Max A.; Lagendijk, Jan J. W.; Seevinck, Peter R.

2017-10-01

An MR-only radiotherapy planning (RTP) workflow would reduce the cost, radiation exposure and uncertainties introduced by CT-MRI registrations. In the case of prostate treatment, one of the remaining challenges currently holding back the implementation of an RTP workflow is the MR-based localisation of intraprostatic gold fiducial markers (FMs), which is crucial for accurate patient positioning. Currently, MR-based FM localisation is clinically performed manually. This is sub-optimal, as manual interaction increases the workload. Attempts to perform automatic FM detection often rely on being able to detect signal voids induced by the FMs in magnitude images. However, signal voids may not always be sufficiently specific, hampering accurate and robust automatic FM localisation. Here, we present an approach that aims at automatic MR-based FM localisation. This method is based on template matching using a library of simulated complex-valued templates, and exploiting the behaviour of the complex MR signal in the vicinity of the FM. Clinical evaluation was performed on seventeen prostate cancer patients undergoing external beam radiotherapy treatment. Automatic MR-based FM localisation was compared to manual MR-based and semi-automatic CT-based localisation (the current gold standard) in terms of detection rate and the spatial accuracy and precision of localisation. The proposed method correctly detected all three FMs in 15/17 patients. The spatial accuracy (mean) and precision (STD) were 0.9 mm and 0.5 mm respectively, which is below the voxel size of 1.1 × 1.1 × 1.2 mm3 and comparable to MR-based manual localisation. FM localisation failed (3/51 FMs) in the presence of bleeding or calcifications in the direct vicinity of the FM. The method was found to be spatially accurate and precise, which is essential for clinical use. To overcome any missed detection, we envision the use of the proposed method along with verification by an observer. This will result in a semi-automatic workflow facilitating the introduction of an MR-only workflow.

Image Fusion for Radiosurgery, Neurosurgery and Hypofractionated Radiotherapy.

PubMed

Inoue, Hiroshi K; Nakajima, Atsushi; Sato, Hiro; Noda, Shin-Ei; Saitoh, Jun-Ichi; Suzuki, Yoshiyuki

2015-03-01

Precise target detection is essential for radiosurgery, neurosurgery and hypofractionated radiotherapy because treatment results and complication rates are related to accuracy of the target definition. In skull base tumors and tumors around the optic pathways, exact anatomical evaluation of cranial nerves are important to avoid adverse effects on these structures close to lesions. Three-dimensional analyses of structures obtained with MR heavy T2-images and image fusion with CT thin-sliced sections are desirable to evaluate fine structures during radiosurgery and microsurgery. In vascular lesions, angiography is most important for evaluations of whole structures from feeder to drainer, shunt, blood flow and risk factors of bleeding. However, exact sites and surrounding structures in the brain are not shown on angiography. True image fusions of angiography, MR images and CT on axial planes are ideal for precise target definition. In malignant tumors, especially recurrent head and neck tumors, biologically active areas of recurrent tumors are main targets of radiosurgery. PET scan is useful for quantitative evaluation of recurrences. However, the examination is not always available at the time of radiosurgery. Image fusion of MR diffusion images with CT is always available during radiosurgery and useful for the detection of recurrent lesions. All images are fused and registered on thin sliced CT sections and exactly demarcated targets are planned for treatment. Follow-up images are also able to register on this CT. Exact target changes, including volume, are possible in this fusion system. The purpose of this review is to describe the usefulness of image fusion for 1) skull base, 2) vascular, 3) recurrent target detection, and 4) follow-up analyses in radiosurgery, neurosurgery and hypofractionated radiotherapy.

Image Fusion for Radiosurgery, Neurosurgery and Hypofractionated Radiotherapy

PubMed Central

Nakajima, Atsushi; Sato, Hiro; Noda, Shin-ei; Saitoh, Jun-ichi; Suzuki, Yoshiyuki

2015-01-01

Precise target detection is essential for radiosurgery, neurosurgery and hypofractionated radiotherapy because treatment results and complication rates are related to accuracy of the target definition. In skull base tumors and tumors around the optic pathways, exact anatomical evaluation of cranial nerves are important to avoid adverse effects on these structures close to lesions. Three-dimensional analyses of structures obtained with MR heavy T2-images and image fusion with CT thin-sliced sections are desirable to evaluate fine structures during radiosurgery and microsurgery. In vascular lesions, angiography is most important for evaluations of whole structures from feeder to drainer, shunt, blood flow and risk factors of bleeding. However, exact sites and surrounding structures in the brain are not shown on angiography. True image fusions of angiography, MR images and CT on axial planes are ideal for precise target definition. In malignant tumors, especially recurrent head and neck tumors, biologically active areas of recurrent tumors are main targets of radiosurgery. PET scan is useful for quantitative evaluation of recurrences. However, the examination is not always available at the time of radiosurgery. Image fusion of MR diffusion images with CT is always available during radiosurgery and useful for the detection of recurrent lesions. All images are fused and registered on thin sliced CT sections and exactly demarcated targets are planned for treatment. Follow-up images are also able to register on this CT. Exact target changes, including volume, are possible in this fusion system. The purpose of this review is to describe the usefulness of image fusion for 1) skull base, 2) vascular, 3) recurrent target detection, and 4) follow-up analyses in radiosurgery, neurosurgery and hypofractionated radiotherapy. PMID:26180676

Intelligent ePR system for evidence-based research in radiotherapy: proton therapy for prostate cancer.

PubMed

Le, Anh H; Liu, Brent; Schulte, Reinhard; Huang, H K

2011-11-01

Proton therapy (PT) utilizes high energy particle proton beam to kill cancer cells at the target region for target cancer therapy. Due to the physical properties of the proton beam, PT delivers dose with higher precision and no exit dose compared to conventional radiotherapy. In PT, patient data are distributed among multiple systems, a hindrance to research on efficacy and effectiveness. A data mining method and a treatment plan navigator utilizing the infrastructure and data repository of a PT electronic patient record (ePR) was developed to minimize radiation toxicity and improve outcomes in prostate cancer treatment. MATERIALS/METHOD(S): The workflow of a proton therapy treatment in a radiation oncology department was reviewed, and a clinical data model and data flow were designed. A prototype PT ePR system with DICOM compliance was developed to manage prostate cancer patient images, treatment plans, and related clinical data. The ePR system consists of four main components: (1) Data Gateway; (2) ePR Server; (3) Decision Support Tools; and (4) Visualization and Display Tools. Decision support and visualization tools are currently developed based on DICOM images, DICOM-RT and DICOM-RT-ION objects data from prostate cancer patients treated with hypofractionation protocol proton therapy were used for evaluating ePR system effectiveness. Each patient data set includes a set of computed tomography (CT) DICOM images and four DICOM-RT and RT-ION objects. In addition, clinical outcomes data collected from PT cases were included to establish a knowledge base for outcomes analysis. A data mining search engine and an intelligent treatment plan navigator (ITPN) were developed and integrated with the ePR system. Evaluation was based on a data set of 39 PT patients and a hypothetical patient. The ePR system was able to facilitate the proton therapy workflow. The PT ePR system was feasible for prostate cancer patient treated with hypofractionation protocol in proton therapy. This ePR system improves efficiency in data collection and integration to facilitate outcomes analysis.

Utilization of neoadjuvant intensity-modulated radiation therapy and proton beam therapy for esophageal cancer in the United States

PubMed Central

Haque, Waqar; Verma, Vivek; Butler, E. Brian

2018-01-01

Background Randomized esophageal cancer (EC) trials have utilized two- or three-dimensional conformal radiotherapy (3DCRT). Advanced radiotherapy (RT) techniques [(ARTs): intensity-modulated radiotherapy (IMRT) and proton beam therapy (PBT)] may have benefits, but are relatively unproven. This is the first study to date evaluating utilization of ARTs versus 3DCRT in the trimodality setting in the United States. Methods The National Cancer Data Base (NCDB) was queried (2004–2013) for newly-diagnosed cT1b-T4bN0/N+M0 EC receiving neoadjuvant CRT followed by esophagectomy. The primary objective was to assess temporal trends, with multivariable logistic regression analysis assessing factors predictive of receiving ARTs. Secondarily, Kaplan-Meier analysis evaluated overall survival (OS), Cox proportional hazards modeling determined variables associated with OS, and postoperative complications were compared between cohorts. Results Altogether, 3,138 patients met criteria; 1,398 (45%) received 3DCRT, and 1,740 (55%) received ARTs (99% IMRT, 1% PBT). Temporally, utilization of ARTs is steadily rising in the United States, from 20% in 2004 to 69% in 2013, corresponding with a progressive decrease in utilization of 3DCRT. ARTs were more often delivered with advancing age, squamous cell histology, N2+ disease, and at academic centers (P<0.05 for all). Centers in the Southwest were more likely to use ARTs, and those in the Midwest least likely (P<0.05 for both). As expected, there were no OS differences (P=0.8477); there were also no differences in postoperative events (P>0.05 for all). Treatment at an academic center independently correlated with improved OS (P<0.001). Conclusions Utilization of ARTs (IMRT in the vast majority) is steadily rising in the United States; 3DCRT is now used in a minority of patients. This has implications for payers and insurance coverage. ART use is impacted by not only age and disease factors, but also regional and facility differences. Treatment at an academic facility independently correlated with higher survival, which has implications for patient counseling. PMID:29755767

Utilization of neoadjuvant intensity-modulated radiation therapy and proton beam therapy for esophageal cancer in the United States.

PubMed

Haque, Waqar; Verma, Vivek; Butler, E Brian; Teh, Bin S

2018-04-01

Randomized esophageal cancer (EC) trials have utilized two- or three-dimensional conformal radiotherapy (3DCRT). Advanced radiotherapy (RT) techniques [(ARTs): intensity-modulated radiotherapy (IMRT) and proton beam therapy (PBT)] may have benefits, but are relatively unproven. This is the first study to date evaluating utilization of ARTs versus 3DCRT in the trimodality setting in the United States. The National Cancer Data Base (NCDB) was queried (2004-2013) for newly-diagnosed cT1b-T4bN0/N+M0 EC receiving neoadjuvant CRT followed by esophagectomy. The primary objective was to assess temporal trends, with multivariable logistic regression analysis assessing factors predictive of receiving ARTs. Secondarily, Kaplan-Meier analysis evaluated overall survival (OS), Cox proportional hazards modeling determined variables associated with OS, and postoperative complications were compared between cohorts. Altogether, 3,138 patients met criteria; 1,398 (45%) received 3DCRT, and 1,740 (55%) received ARTs (99% IMRT, 1% PBT). Temporally, utilization of ARTs is steadily rising in the United States, from 20% in 2004 to 69% in 2013, corresponding with a progressive decrease in utilization of 3DCRT. ARTs were more often delivered with advancing age, squamous cell histology, N2+ disease, and at academic centers (P<0.05 for all). Centers in the Southwest were more likely to use ARTs, and those in the Midwest least likely (P<0.05 for both). As expected, there were no OS differences (P=0.8477); there were also no differences in postoperative events (P>0.05 for all). Treatment at an academic center independently correlated with improved OS (P<0.001). Utilization of ARTs (IMRT in the vast majority) is steadily rising in the United States; 3DCRT is now used in a minority of patients. This has implications for payers and insurance coverage. ART use is impacted by not only age and disease factors, but also regional and facility differences. Treatment at an academic facility independently correlated with higher survival, which has implications for patient counseling.

Next generation multi-scale biophysical characterization of high precision cancer particle radiotherapy using clinical proton, helium-, carbon- and oxygen ion beams

PubMed Central

Niklas, Martin; Zimmermann, Ferdinand; Chaudhri, Naved; Krunic, Damir; Tessonnier, Thomas; Ferrari, Alfredo; Parodi, Katia; Jäkel, Oliver; Debus, Jürgen; Haberer, Thomas; Abdollahi, Amir

2016-01-01

The growing number of particle therapy facilities worldwide landmarks a novel era of precision oncology. Implementation of robust biophysical readouts is urgently needed to assess the efficacy of different radiation qualities. This is the first report on biophysical evaluation of Monte Carlo simulated predictive models of prescribed dose for four particle qualities i.e., proton, helium-, carbon- or oxygen ions using raster-scanning technology and clinical therapy settings at HIT. A high level of agreement was found between the in silico simulations, the physical dosimetry and the clonogenic tumor cell survival. The cell fluorescence ion track hybrid detector (Cell-Fit-HD) technology was employed to detect particle traverse per cell nucleus. Across a panel of radiobiological surrogates studied such as late ROS accumulation and apoptosis (caspase 3/7 activation), the relative biological effectiveness (RBE) chiefly correlated with the radiation species-specific spatio-temporal pattern of DNA double strand break (DSB) formation and repair kinetic. The size and the number of residual nuclear γ-H2AX foci increased as a function of linear energy transfer (LET) and RBE, reminiscent of enhanced DNA-damage complexity and accumulation of non-repairable DSB. These data confirm the high relevance of complex DSB formation as a central determinant of cell fate and reliable biological surrogates for cell survival/RBE. The multi-scale simulation, physical and radiobiological characterization of novel clinical quality beams presented here constitutes a first step towards development of high precision biologically individualized radiotherapy. PMID:27494855

[Basic principles and results of brachytherapy in gynecological oncology].

PubMed

Kanaev, S V; Turkevich, V G; Baranov, S B; Savel'eva, V V

2014-01-01

The fundamental basics of contact radiation therapy (brachytherapy) for gynecological cancer are presented. During brachytherapy the principles of conformal radiotherapy should be implemented, the aim of which is to sum the maximum possible dose of radiation to the tumor and decrease the dose load in adjacent organs and tissues, which allows reducing the frequency of radiation damage at treatment of primary tumors. It is really feasible only on modern technological level, thanks to precision topometry preparation, optimal computer dosimetrical and radiobiological planning of each session and radiotherapy in general. Successful local and long-term results of the contact radiation therapy for cancer of cervix and endometrium are due to optimal anatomical and topometrical ratio of the tumor localization, radioactive sources, and also physical and radiobiological laws of distribution and effects of ionizing radiation, the dose load accounting rules.

The future of image-guided radiotherapy will be MR guided

PubMed Central

Wen, Zhifei; Sadagopan, Ramaswamy; Wang, Jihong; Ibbott, Geoffrey S

2017-01-01

Advances in image-guided radiotherapy (RT) have allowed for dose escalation and more precise radiation treatment delivery. Each decade brings new imaging technologies to help improve RT patient setup. Currently, the most frequently used method of three-dimensional pre-treatment image verification is performed with cone beam CT. However, more recent developments have provided RT with the ability to have on-board MRI coupled to the teleradiotherapy unit. This latest tool for treating cancer is known as MR-guided RT. Several varieties of these units have been designed and installed in centres across the globe. Their prevalence, history, advantages and disadvantages are discussed in this review article. In preparation for the next generation of image-guided RT, this review also covers where MR-guided RT might be heading in the near future. PMID:28256898

A New Era of Image Guidance with Magnetic Resonance-guided Radiation Therapy for Abdominal and Thoracic Malignancies

PubMed Central

Paliwal, Bhudatt; Hill, Patrick; Bayouth, John E; Geurts, Mark W; Baschnagel, Andrew M; Bradley, Kristin A; Harari, Paul M; Rosenberg, Stephen; Brower, Jeffrey V; Wojcieszynski, Andrzej P; Hullett, Craig; Bayliss, R A; Labby, Zacariah E; Bassetti, Michael F

2018-01-01

Magnetic resonance-guided radiation therapy (MRgRT) offers advantages for image guidance for radiotherapy treatments as compared to conventional computed tomography (CT)-based modalities. The superior soft tissue contrast of magnetic resonance (MR) enables an improved visualization of the gross tumor and adjacent normal tissues in the treatment of abdominal and thoracic malignancies. Online adaptive capabilities, coupled with advanced motion management of real-time tracking of the tumor, directly allow for high-precision inter-/intrafraction localization. The primary aim of this case series is to describe MR-based interventions for localizing targets not well-visualized with conventional image-guided technologies. The abdominal and thoracic sites of the lung, kidney, liver, and gastric targets are described to illustrate the technological advancement of MR-guidance in radiotherapy. PMID:29872602

Precision oncology: origins, optimism, and potential.

PubMed

Prasad, Vinay; Fojo, Tito; Brada, Michael

2016-02-01

Imatinib, the first and arguably the best targeted therapy, became the springboard for developing drugs aimed at molecular targets deemed crucial to tumours. As this development unfolded, a revolution in the speed and cost of genetic sequencing occurred. The result--an armamentarium of drugs and an array of molecular targets--set the stage for precision oncology, a hypothesis that cancer treatment could be markedly improved if therapies were guided by a tumour's genomic alterations. Drawing lessons from the biological basis of cancer and recent empirical investigations, we take a more measured view of precision oncology's promise. Ultimately, the promise is not our concern, but the threshold at which we declare success. We review reports of precision oncology alongside those of precision diagnostics and novel radiotherapy approaches. Although confirmatory evidence is scarce, these interventions have been widely endorsed. We conclude that the current path will probably not be successful or, at a minimum, will have to undergo substantive adjustments before it can be successful. For the sake of patients with cancer, we hope one form of precision oncology will deliver on its promise. However, until confirmatory studies are completed, precision oncology remains unproven, and as such, a hypothesis in need of rigorous testing. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cost and resource utilization in cervical cancer management: a real-world retrospective cost analysis.

PubMed

Cromwell, I; Ferreira, Z; Smith, L; van der Hoek, K; Ogilvie, G; Coldman, A; Peacock, S J

2016-02-01

We set out to assess the health care resource utilization and cost of cervical cancer from the perspective of a single-payer health care system. Retrospective observational data for women diagnosed with cervical cancer in British Columbia between 2004 and 2009 were analyzed to calculate patient-level resource utilization patterns from diagnosis to death or 5-year discharge. Domains of resource use within the scope of this cost analysis were chemotherapy, radiotherapy, and brachytherapy administered by the BC Cancer Agency; resource utilization related to hospitalization and outpatient visits as recorded by the B.C. Ministry of Health; medically required services billed under the B.C. Medical Services Plan; and prescriptions dispensed under British Columbia's health insurance programs. Unit costs were applied to radiotherapy and brachytherapy, producing per-patient costs. The mean cost per case of treating cervical cancer in British Columbia was $19,153 (standard error: $3,484). Inpatient hospitalizations, at 35%, represented the largest proportion of the total cost (95% confidence interval: 32.9% to 36.9%). Costs were compared for subgroups of the total cohort. As health care systems change the way they manage, screen for, and prevent cervical cancer, cost-effectiveness evaluations of the overall approach will require up-to-date data for resource utilization and costs. We provide information suitable for such a purpose and also identify factors that influence costs.

High-dose accelerated hypofractionated three-dimensional conformal radiotherapy (at 3 Gy/fraction) with concurrent vinorelbine and carboplatin chemotherapy in locally advanced non-small-cell lung cancer: a feasibility study.

PubMed

Liu, Yue-E; Lin, Qiang; Meng, Fan-Jie; Chen, Xue-Ji; Ren, Xiao-Cang; Cao, Bin; Wang, Na; Zong, Jie; Peng, Yu; Ku, Ya-Jun; Chen, Yan

2013-08-11

Increasing the radiotherapy dose can result in improved local control for non-small-cell lung cancer (NSCLC) and can thereby improve survival. Accelerated hypofractionated radiotherapy can expose tumors to a high dose of radiation in a short period of time, but the optimal treatment regimen remains unclear. The purpose of this study was to evaluate the feasibility of utilizing high-dose accelerated hypofractionated three-dimensional conformal radiotherapy (at 3 Gy/fraction) with concurrent vinorelbine (NVB) and carboplatin (CBP) chemotherapy for the treatment of local advanced NSCLC. Untreated patients with unresectable stage IIIA/IIIB NSCLC or patients with a recurrence of NSCLC received accelerated hypofractionated three-dimensional conformal radiotherapy. The total dose was greater than or equal to 60 Gy. The accelerated hypofractionated radiotherapy was conducted once daily at 3 Gy/fraction with 5 fractions per week, and the radiotherapy was completed in 5 weeks. In addition to radiotherapy, the patients also received at least 1 cycle of a concurrent two-drug chemotherapy regimen of NVB and CBP. A total of 26 patients (19 previously untreated cases and 7 cases of recurrent disease) received 60Gy-75Gy radiotherapy with concurrent chemotherapy. All of the patients underwent evaluations for toxicity and preliminary therapeutic efficacy. There were no treatment-related deaths within the entire patient group. The major acute adverse reactions were radiation esophagitis (88.5%) and radiation pneumonitis (42.3%). The percentages of grade III acute radiation esophagitis and grade III radiation pneumonitis were 15.4% and 7.7%, respectively. Hematological toxicities were common and did not significantly affect the implementation of chemoradiotherapy after supportive treatment. Two patients received high dose of 75 Gy had grade III late esophageal toxicity, and none had grade IV and above. Grade III and above late lung toxicity did not occur. High-dose accelerated hypofractionated three-dimensional conformal radiotherapy with a dose of 60 Gy or greater with concurrent NVB and CBP chemotherapy might be feasible. However esophagus toxicity needs special attention. A phase I trial is recommended to obtain the maximum tolerated radiation dose of accelerated hypofractionated radiotherapy with concurrent chemotherapy.

High-dose accelerated hypofractionated three-dimensional conformal radiotherapy (at 3 Gy/fraction) with concurrent vinorelbine and carboplatin chemotherapy in locally advanced non-small-cell lung cancer: a feasibility study

PubMed Central

2013-01-01

Background Increasing the radiotherapy dose can result in improved local control for non-small-cell lung cancer (NSCLC) and can thereby improve survival. Accelerated hypofractionated radiotherapy can expose tumors to a high dose of radiation in a short period of time, but the optimal treatment regimen remains unclear. The purpose of this study was to evaluate the feasibility of utilizing high-dose accelerated hypofractionated three-dimensional conformal radiotherapy (at 3 Gy/fraction) with concurrent vinorelbine (NVB) and carboplatin (CBP) chemotherapy for the treatment of local advanced NSCLC. Methods Untreated patients with unresectable stage IIIA/IIIB NSCLC or patients with a recurrence of NSCLC received accelerated hypofractionated three-dimensional conformal radiotherapy. The total dose was greater than or equal to 60 Gy. The accelerated hypofractionated radiotherapy was conducted once daily at 3 Gy/fraction with 5 fractions per week, and the radiotherapy was completed in 5 weeks. In addition to radiotherapy, the patients also received at least 1 cycle of a concurrent two-drug chemotherapy regimen of NVB and CBP. Results A total of 26 patients (19 previously untreated cases and 7 cases of recurrent disease) received 60Gy-75Gy radiotherapy with concurrent chemotherapy. All of the patients underwent evaluations for toxicity and preliminary therapeutic efficacy. There were no treatment-related deaths within the entire patient group. The major acute adverse reactions were radiation esophagitis (88.5%) and radiation pneumonitis (42.3%). The percentages of grade III acute radiation esophagitis and grade III radiation pneumonitis were 15.4% and 7.7%, respectively. Hematological toxicities were common and did not significantly affect the implementation of chemoradiotherapy after supportive treatment. Two patients received high dose of 75 Gy had grade III late esophageal toxicity, and none had grade IV and above. Grade III and above late lung toxicity did not occur. Conclusion High-dose accelerated hypofractionated three-dimensional conformal radiotherapy with a dose of 60 Gy or greater with concurrent NVB and CBP chemotherapy might be feasible. However esophagus toxicity needs special attention. A phase I trial is recommended to obtain the maximum tolerated radiation dose of accelerated hypofractionated radiotherapy with concurrent chemotherapy. PMID:23937855

Synthetic diamond devices for radio-oncology applications

NASA Astrophysics Data System (ADS)

Descamps, C.; Tromson, D.; Mer, C.; Nesládek, M.; Bergonzo, P.; Benabdesselam, M.

2006-09-01

Diamond exhibits a range of outstanding properties that make it a material of interest for radiation detection and particularly in the field of dosimetry applications. In fact, its crystallographic structure makes it chemically inert and radiation hard. Moreover, its atomic number (carbon Z = 6) close to the equivalent effective atomic number of human soft tissues (Z = 7.4) and of water (reference material in radiotherapy) enables a direct evaluation of the deposited dose without requiring corrections for material nature or energy. Finally, as a bio-compatible material, it can be sterilised, and it is non-toxic thus giving strong advantages for medical uses. Natural diamonds are expensive, rare and their use implies a severe gem selection to fabricate reproducible and reliable devices. The emergence of synthetic samples from the chemical vapour deposition (CVD) technique offers new possibilities in the fabrication of ionisation chamber for the particular field of radiotherapy. Previous studies have shown that defect levels present in material clearly influence the device response under irradiation. Therefore, in order to optimise dosimetric characteristics needed in radiotherapy applications, various low and precisely nitrogen concentrations were incorporated in the material during growth. Influence of these incorporations on ionisation chamber response under medical cobalt irradiator is presented in this paper.

Laue lens for radiotherapy applications through a focused hard x-ray beam: a feasibility study on requirements and tolerances

NASA Astrophysics Data System (ADS)

Camattari, Riccardo

2017-09-01

Focusing a hard x-ray beam would represent an innovative technique for tumour treatment, since such a beam may deliver a dose to a tumour located at a given depth under the skin, sparing the surrounding healthy cells. A detailed study of a focusing system for hard x-ray aimed at radiotherapy is presented here. Such a focusing system, named Laue lens, exploits x-ray diffraction and consists of a series of crystals disposed as concentric rings capable of concentrating a flux of x-rays towards a focusing point. A feasibility study regarding the positioning tolerances of the crystalline optical elements has been carried out. It is shown that a Laue lens can effectively be used in the context of radiotherapy for tumour treatments provided that the mounting errors are below certain values, which are reachable in the modern micromechanics. An extended survey based on an analytical approach and on simulations is presented for precisely estimating all the contributions of each mounting error, analysing their effect on the focal spot of the Laue lens. Finally, a simulation for evaluating the released dose in a water phantom is shown.

FlexyDos3D: a deformable anthropomorphic 3D radiation dosimeter: radiation properties

NASA Astrophysics Data System (ADS)

De Deene, Y.; Skyt, P. S.; Hil, R.; Booth, J. T.

2015-02-01

Three dimensional radiation dosimetry has received growing interest with the implementation of highly conformal radiotherapy treatments. The radiotherapy community faces new challenges with the commissioning of image guided and image gated radiotherapy treatments (IGRT) and deformable image registration software. A new three dimensional anthropomorphically shaped flexible dosimeter, further called ‘FlexyDos3D’, has been constructed and a new fast optical scanning method has been implemented that enables scanning of irregular shaped dosimeters. The FlexyDos3D phantom can be actuated and deformed during the actual treatment. FlexyDos3D offers the additional advantage that it is easy to fabricate, is non-toxic and can be molded in an arbitrary shape with high geometrical precision. The dosimeter formulation has been optimized in terms of dose sensitivity. The influence of the casting material and oxygen concentration has also been investigated. The radiophysical properties of this new dosimeter are discussed including stability, spatial integrity, temperature dependence of the dosimeter during radiation, readout and storage, dose rate dependence and tissue equivalence. The first authors Y De Deene and P S Skyt made an equivalent contribution to the experimental work presented in this paper.

Clinical outcome after high-precision radiotherapy for skull base meningiomas: Pooled data from three large German centers for radiation oncology.

PubMed

Combs, Stephanie E; Farzin, Mostafa; Boehmer, Julia; Oehlke, Oliver; Molls, Michael; Debus, Jürgen; Grosu, Anca-Ligia

2018-05-01

To evaluate outcome in patients with base of skull meningiomas treated with modern high precision radiation therapy (RT) techniques. 927 patients from three centers were treated with either radiosurgery or fractionated high-precision RT for meningiomas. Treatment planning was based on CT and MRI following institutional guidelines. For radiosurgery, a median dose of 13 Gy was applied, for fractionated treatments, a median dose of 54 Gy in 1.8 Gy single fractions was prescribed. Follow-up included a clinical examination as well as contrast-enhanced imaging. All patients were followed up prospectively after radiotherapy in the three departments within a strict follow-up regimen. The median follow-up time was 81 months (range 1-348 months). Median local control was 79 months (range 1-348 months). Local control (LC) was 98% at 1 year, 94% at 3 years, 92% at 5 years and 86% at 10 years. There was no difference between radiosurgery and fractionated RT. We analyzed the influence of higher doses on LC and could show that dose did not impact LC. Moreover, there was no difference between 54 Gy and 57.6 Gy in the fractionated group. Side effects were below 5% in both groups without any severe treatment-related complications. Based on the pooled data analysis this manuscript provides a large series of meningiomas of the skull base treated with modern high precision RT demonstrating excellent local control and low rates of side effects. Such data support the recommendation of RT for skull base meningiomas in the interdisciplinary tumor board discussions. The strong role of RT must influence treatment recommendations keeping in mind the individual risk-benefit profile of treatment alternatives. Copyright © 2018 Elsevier B.V. All rights reserved.

Immobilisation precision in VMAT for oral cancer patients

NASA Astrophysics Data System (ADS)

Norfadilah, M. N.; Ahmad, R.; Heng, S. P.; Lam, K. S.; Radzi, A. B. Ahmad; John, L. S. H.

2017-05-01

A study was conducted to evaluate and quantify a precision of the interfraction setup with different immobilisation devices throughout the treatment time. Local setup accuracy was analysed for 8 oral cancer patients receiving radiotherapy; 4 with HeadFIX® mouthpiece moulded with wax (HFW) and 4 with 10 ml/cc syringe barrel (SYR). Each patients underwent Image Guided Radiotherapy (IGRT) with total of 209 cone-beam computed tomography (CBCT) data sets for position set up errors measurement. The setup variations in the mediolateral (ML), craniocaudal (CC), and anteroposterior (AP) dimensions were measured. Overall mean displacement (M), the population systematic (Σ) and random (σ) errors and the 3D vector length were calculated. Clinical target volume to planning target volume (CTV-PTV) margins were calculated according to the van Herk formula (2.5Σ+0.7σ). The M values for both group were < 1 mm and < 1° in all translational and rotational directions. This indicate there is no significant imprecision in the equipment (lasers) and during procedure. The interfraction translational 3 dimension vector for HFW and SYR were 1.93±0.66mm and 3.84±1.34mm, respectively. The interfraction average rotational error were 0.00°±0.65° and 0.34°±0.59°, respectively. CTV-PTV margins along the 3 translational axis (Right-Left, Superior-Inferior, Anterior-Posterior) calculated were 3.08, 2.22 and 0.81 mm for HFW and 3.76, 6.24 and 5.06 mm for SYR. The results of this study have demonstrated that HFW more precise in reproducing patient position compared to conventionally used SYR (p<0.001). All margin calculated did not exceed hospital protocol (5mm) except S-I and A-P axes using syringe. For this reason, a daily IGRT is highly recommended to improve the immobilisation precision.

SU-E-T-56: A Novel Approach to Computing Expected Value and Variance of Point Dose From Non-Gated Radiotherapy Delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, S; Zhu, X; Zhang, M

Purpose: Randomness in patient internal organ motion phase at the beginning of non-gated radiotherapy delivery may introduce uncertainty to dose received by the patient. Concerns of this dose deviation from the planned one has motivated many researchers to study this phenomenon although unified theoretical framework for computing it is still missing. This study was conducted to develop such framework for analyzing the effect. Methods: Two reasonable assumptions were made: a) patient internal organ motion is stationary and periodic; b) no special arrangement is made to start a non -gated radiotherapy delivery at any specific phase of patient internal organ motion.more » A statistical ensemble was formed consisting of patient’s non-gated radiotherapy deliveries at all equally possible initial organ motion phases. To characterize the patient received dose, statistical ensemble average method is employed to derive formulae for two variables: expected value and variance of dose received by a patient internal point from a non-gated radiotherapy delivery. Fourier Series was utilized to facilitate our analysis. Results: According to our formulae, the two variables can be computed from non-gated radiotherapy generated dose rate time sequences at the point’s corresponding locations on fixed phase 3D CT images sampled evenly in time over one patient internal organ motion period. The expected value of point dose is simply the average of the doses to the point’s corresponding locations on the fixed phase CT images. The variance can be determined by time integration in terms of Fourier Series coefficients of the dose rate time sequences on the same fixed phase 3D CT images. Conclusion: Given a non-gated radiotherapy delivery plan and patient’s 4D CT study, our novel approach can predict the expected value and variance of patient radiation dose. We expect it to play a significant role in determining both quality and robustness of patient non-gated radiotherapy plan.« less

Improved Overall Survival with Aggressive Primary Tumor Radiotherapy for Patients with Metastatic Esophageal Cancer.

PubMed

Guttmann, David M; Mitra, Nandita; Bekelman, Justin; Metz, James M; Plastaras, John; Feng, Weiwei; Swisher-McClure, Samuel

2017-07-01

The aim of this study was to characterize utilization and survival outcomes associated with primary tumor-directed radiotherapy (PTDRT) in patients with newly diagnosed metastatic esophageal cancer. We conducted an observational cohort study using the National Cancer Data Base to evaluate patients with newly diagnosed metastatic esophageal cancer between 2004 and 2012. Overall survival outcomes after treatment with chemotherapy plus conventional palliative dose radiotherapy (<5040 cGy), chemotherapy plus definitive dose radiotherapy (≥5040 cGy), or chemotherapy alone were compared by using Cox proportional hazards models with inverse probability of treatment weighting using the propensity score. Potential unmeasured confounding was assessed through sensitivity analyses. The final cohort consisted of 12,683 patients: 57% were treated with chemotherapy alone, 24% were treated with chemotherapy plus palliative dose radiotherapy, and 19% were treated with chemotherapy plus definitive dose radiotherapy. Compared with chemotherapy alone, chemotherapy plus definitive dose radiotherapy was associated with improved survival (median overall survival of 8.3 versus 11.3 months [hazard ratio = 0.72, 95% confidence interval: 0.70-0.74, p ≤ 0.001]), whereas chemotherapy plus palliative dose radiotherapy was associated with slightly inferior outcomes (median overall survival of 8.3 months versus 7.5 months (hazard ratio = 1.10, 95% confidence interval 1.07-1.13, p ≤ 0.001). These findings were robust to potential unmeasured confounding in sensitivity analyses. Additionally, landmark analyses confirmed these findings in patients surviving 12 months or longer. Definitive dose, but not conventional palliative dose, PTDRT is associated with improved overall survival in metastatic esophageal cancer, suggesting that local control may be important to prognosis. These findings support integrating PTDRT into future clinical trials aimed at refining personalized treatment for patients with metastatic esophageal cancer. Copyright © 2017 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

Review: mucosal melanoma of the head and neck.

PubMed

Gavriel, Haim; McArthur, Grant; Sizeland, Andrew; Henderson, Michael

2011-08-01

Head and neck mucosal melanoma (MM) is a rare and aggressive neoplasm, with high rates of local, regional, and distant failure. Owing to the small size of most reported series and their retrospective nature, and the lack of uniform comprehensive staging system, the effect of various treatment strategies on disease control and survival has been difficult to assess. The optimal management of head and neck MM is not well defined. Surgical treatment has being advocated as the primary treatment modality, with growing consideration for postoperative radiotherapy, as wide surgical resection in the head and neck region is often difficult. Radiotherapy is recently reported as a beneficial management modality, regardless of the fact that MM has been considered to be radioresistant. As significant morbidity is expected in high doses of radiotherapy to the head and neck region, new radiographic modalities with better precision are required. Furthermore, high-energy radiotherapy was suggested as a better therapy to mucosal MM due to the suggested biology of the tumor. The high rates of locoregional recurrence and distant metastasis also suggest that a systemic treatment is needed. Currently, there is no role for adjuvant systemic therapy for patients who have been successfully resected, but recent developments in the understanding of the biology of melanoma and, in particular, specific growth pathways holds promise for the future. We strongly recommend further evaluation of the role of chemotherapy and immunotherapy to decrease the rates of distant metastasis and improve survival.

Radiotherapy equipment and departments in the European countries: final results from the ESTRO-HERO survey.

PubMed

Grau, Cai; Defourny, Noémie; Malicki, Julian; Dunscombe, Peter; Borras, Josep M; Coffey, Mary; Slotman, Ben; Bogusz, Marta; Gasparotto, Chiara; Lievens, Yolande; Kokobobo, Arianit; Sedlmayer, Felix; Slobina, Elena; Feyen, Karen; Hadjieva, Tatiana; Odrazka, Karel; Grau Eriksen, Jesper; Jaal, Jana; Bly, Ritva; Chauvet, Bruno; Willich, Normann; Polgar, Csaba; Johannsson, Jakob; Cunningham, Moya; Magrini, Stefano; Atkocius, Vydmantas; Untereiner, Michel; Pirotta, Martin; Karadjinovic, Vanja; Levernes, Sverre; Sladowski, Krystol; Lurdes Trigo, Maria; Šegedin, Barbara; Rodriguez, Aurora; Lagerlund, Magnus; Pastoors, Bert; Hoskin, Peter; Vaarkamp, Jaap; Cleries Soler, Ramon

2014-08-01

Documenting the distribution of radiotherapy departments and the availability of radiotherapy equipment in the European countries is an important part of HERO - the ESTRO Health Economics in Radiation Oncology project. HERO has the overall aim to develop a knowledge base of the provision of radiotherapy in Europe and build a model for health economic evaluation of radiation treatments at the European level. The aim of the current report is to describe the distribution of radiotherapy equipment in European countries. An 84-item questionnaire was sent out to European countries, principally through their national societies. The current report includes a detailed analysis of radiotherapy departments and equipment (questionnaire items 26-29), analyzed in relation to the annual number of treatment courses and the socio-economic status of the countries. The analysis is based on validated responses from 28 of the 40 European countries defined by the European Cancer Observatory (ECO). A large variation between countries was found for most parameters studied. There were 2192 linear accelerators, 96 dedicated stereotactic machines, and 77 cobalt machines reported in the 27 countries where this information was available. A total of 12 countries had at least one cobalt machine in use. There was a median of 0.5 simulator per MV unit (range 0.3-1.5) and 1.4 (range 0.4-4.4) simulators per department. Of the 874 simulators, a total of 654 (75%) were capable of 3D imaging (CT-scanner or CBCT-option). The number of MV machines (cobalt, linear accelerators, and dedicated stereotactic machines) per million inhabitants ranged from 1.4 to 9.5 (median 5.3) and the average number of MV machines per department from 0.9 to 8.2 (median 2.6). The average number of treatment courses per year per MV machine varied from 262 to 1061 (median 419). While 69% of MV units were capable of IMRT only 49% were equipped for image guidance (IGRT). There was a clear relation between socio-economic status, as measured by GNI per capita, and availability of radiotherapy equipment in the countries. In many low income countries in Southern and Central-Eastern Europe there was very limited access to radiotherapy and especially to equipment for IMRT or IGRT. The European average number of MV machines per million inhabitants and per department is now better in line with QUARTS recommendations from 2005, but the survey also showed a significant heterogeneity in the access to modern radiotherapy equipment in Europe. High income countries especially in Northern-Western Europe are well-served with radiotherapy resources, other countries are facing important shortages of both equipment in general and especially machines capable of delivering high precision conformal treatments (IMRT, IGRT). Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

MRI-guided Dose-escalated Salvage Radiotherapy for Bulky Bladder Neck Recurrence of Prostate Cancer

PubMed Central

Tyran, Marguerite; Steinberg, Michael L.; Holden, Stuart B; Cao, Minsong

2018-01-01

Nearly 30% of patients treated with radical prostatectomy for prostate cancer ultimately develop biochemical recurrences, and nearly a quarter of men with nonpalpable biochemical recurrences have gross local recurrences identified with magnetic resonance imaging (MRI). The only curative intervention for patients with recurrent disease after radical prostatectomy is salvage radiotherapy – this is particularly true for patients with gross local recurrences. Furthermore, even in patients with an incurable metastatic disease, a local recurrence can be the source of significant morbidity and should be addressed. Delivering a sufficient dose of radiation in the postoperative setting to control gross disease while minimizing toxicity poses a significant technical challenge. Because of the inherent uncertainty in the verification of gross disease positioning with standard onboard imaging technologies, large margins must be used. Larger margins, in turn, will lead to larger volumes of tissue receiving high doses of radiation, potentially increasing long-term toxicity. Herein, we present the case of a patient with a bulky gross recurrence (>40 cm3) at the bladder neck and synchronous metastatic disease who was referred for salvage radiotherapy after a multidisciplinary consensus recommendation to pursue local therapy for mitigating urinary morbidity from the bulky tumor. The case illustrates the utilization of MRI-guided radiotherapy to allow significant margin reduction, thereby facilitating the delivery of an escalated dose of radiotherapy to a bulky recurrence. PMID:29805929

Radiation therapy affects the mechanical behavior of human umbilical vein endothelial cells.

PubMed

Mohammadkarim, Alireza; Tabatabaei, Mohammad; Parandakh, Azim; Mokhtari-Dizaji, Manijhe; Tafazzoli-Shadpour, Mohammad; Khani, Mohammad-Mehdi

2018-06-06

Radiation therapy has been widely utilized as an effective method to eliminate malignant tumors and cancerous cells. However, subjection of healthy tissues and the related networks of blood vessels adjacent to the tumor area to irradiation is inevitable. The aim of this study was to investigate the consequent effects of fractionation radiotherapy on the mechanical characteristics of human umbilical vein endothelial cells (HUVECs) through alterations in cytoskeleton organization and cell and nucleus morphology. In order to simulate the clinical condition of radiotherapy, the HUVECs were exposed to the specific dose of 2 Gy for 1-4 times among four groups with incremental total dose from 2 Gy up to 8 Gy. Fluorescence staining was performed to label F-actin filaments and nuclei. Micropipette aspiration and standard linear solid model were employed to evaluate the elastic and viscoelastic characteristics of the HUVECs. Radiotherapy significantly increased cell elastic moduli. Due to irradiation, instantaneous and equilibrium Young's modulus were also increased. Radiotherapy diminished HUVECs viscoelastic behavior and shifted their creep compliance curves downward. Furthermore, gamma irradiation elevated the nuclei sizes and to a lesser extent the cells sizes resulting in the accumulation of F-actin filaments within the rest of cell body. Endothelial stiffening correlates with endothelial dysfunction, hence the results may be helpful when the consequent effects of radiotherapy are the focus of concern. Copyright © 2018. Published by Elsevier Ltd.

Projected Improvements in Accelerated Partial Breast Irradiation Using a Novel Breast Stereotactic Radiotherapy Device: A Dosimetric Analysis.

PubMed

Snider, James W; Mutaf, Yildirim; Nichols, Elizabeth; Hall, Andrea; Vadnais, Patrick; Regine, William F; Feigenberg, Steven J

2017-01-01

Accelerated partial breast irradiation has caused higher than expected rates of poor cosmesis. At our institution, a novel breast stereotactic radiotherapy device has demonstrated dosimetric distributions similar to those in brachytherapy. This study analyzed comparative dose distributions achieved with the device and intensity-modulated radiation therapy accelerated partial breast irradiation. Nine patients underwent computed tomography simulation in the prone position using device-specific immobilization on an institutional review board-approved protocol. Accelerated partial breast irradiation target volumes (planning target volume_10mm) were created per the National Surgical Adjuvant Breast and Bowel Project B-39 protocol. Additional breast stereotactic radiotherapy volumes using smaller margins (planning target volume_3mm) were created based on improved immobilization. Intensity-modulated radiation therapy and breast stereotactic radiotherapy accelerated partial breast irradiation plans were separately generated for appropriate volumes. Plans were evaluated based on established dosimetric surrogates of poor cosmetic outcomes. Wilcoxon rank sum tests were utilized to contrast volumes of critical structures receiving a percentage of total dose ( Vx). The breast stereotactic radiotherapy device consistently reduced dose to all normal structures with equivalent target coverage. The ipsilateral breast V20-100 was significantly reduced ( P < .05) using planning target volume_10mm, with substantial further reductions when targeting planning target volume_3mm. Doses to the chest wall, ipsilateral lung, and breast skin were also significantly lessened. The breast stereotactic radiotherapy device's uniform dosimetric improvements over intensity-modulated accelerated partial breast irradiation in this series indicate a potential to improve outcomes. Clinical trials investigating this benefit have begun accrual.

Treatment planning and 3D dose verification of whole brain radiation therapy with hippocampal avoidance in rats

NASA Astrophysics Data System (ADS)

Yoon, S. W.; Miles, D.; Cramer, C.; Reinsvold, M.; Kirsch, D.; Oldham, M.

2017-05-01

Despite increasing use of stereotactic radiosurgery, whole brain radiotherapy (WBRT) continues to have a therapeutic role in a selected subset of patients. Selectively avoiding the hippocampus during such treatment (HA-WBRT) emerged as a strategy to reduce the cognitive morbidity associated with WBRT and gave rise to a recently published the phase II trial (RTOG 0933) and now multiple ongoing clinical trials. While conceptually hippocampal avoidance is supported by pre-clinical evidence showing that the hippocampus plays a vital role in memory, there is minimal pre-clinic data showing that selectively avoiding the hippocampus will reduce radiation-induced cognitive decline. Largely the lack of pre-clinical evidence can be attributed to the technical hurdles associated with delivering precise conformal treatment the rat brain. In this work we develop a novel conformal HA-WBRT technique for Wistar rats, utilizing a 225kVp micro-irradiator with precise 3D-printed radiation blocks designed to spare hippocampus while delivering whole brain dose. The technique was verified on rodent-morphic Presage® 3D dosimeters created from micro-CT scans of Wistar rats with Duke Large Field-of-View Optical Scanner (DLOS) at 1mm isotropic voxel resolution. A 4-field box with parallel opposed AP-PA and two lateral opposed fields was explored with conformal hippocampal sparing aided by 3D-printed radiation blocks. The measured DVH aligned reasonably well with that calculated from SmART Plan Monte Carlo simulations with simulated blocks for 4-field HA-WBRT with both demonstrating hippocampal sparing of 20% volume receiving less than 30% the prescription dose.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benedict, Stanley H.; Bova, Frank J.; Clark, Brenda

This article is a tribute to the pioneering medical physicists over the last 50 years who have participated in the research, development, and commercialization of stereotactic radiosurgery (SRS) and stereotactic radiotherapy utilizing a wide range of technology. The authors have described the evolution of SRS through the eyes of physicists from its beginnings with the Gamma Knife in 1951 to proton and charged particle therapy; modification of commercial linacs to accommodate high precision SRS setups; the multitude of accessories that have enabled fine tuning patients for relocalization, immobilization, and repositioning with submillimeter accuracy; and finally the emerging technology of SBRT.more » A major theme of the article is the expanding role of the medical physicist from that of advisor to the neurosurgeon to the current role as a primary driver of new technology that has already led to an adaptation of cranial SRS to other sites in the body, including, spine, liver, and lung. SRS continues to be at the forefront of the impetus to provide technological precision for radiation therapy and has demonstrated a host of downstream benefits in improving delivery strategies for conventional therapy as well. While this is not intended to be a comprehensive history, and the authors could not delineate every contribution by all of those working in the pursuit of SRS development, including physicians, engineers, radiobiologists, and the rest of the therapy and dosimetry staff in this important and dynamic radiation therapy modality, it is clear that physicists have had a substantial role in the development of SRS and theyincreasingly play a leading role in furthering SRS technology.« less

WE-AB-202-09: Feasibility and Quantitative Analysis of 4DCT-Based High Precision Lung Elastography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hasse, K; Neylon, J; Low, D

2016-06-15

Purpose: The purpose of this project is to derive high precision elastography measurements from 4DCT lung scans to facilitate the implementation of elastography in a radiotherapy context. Methods: 4DCT scans of the lungs were acquired, and breathing stages were subsequently registered to each other using an optical flow DIR algorithm. The displacement of each voxel gleaned from the registration was taken to be the ground-truth deformation. These vectors, along with the 4DCT source datasets, were used to generate a GPU-based biomechanical simulation that acted as a forward model to solve the inverse elasticity problem. The lung surface displacements were appliedmore » as boundary constraints for the model-guided lung tissue elastography, while the inner voxels were allowed to deform according to the linear elastic forces within the model. A biomechanically-based anisotropic convergence magnification technique was applied to the inner voxels in order to amplify the subtleties of the interior deformation. Solving the inverse elasticity problem was accomplished by modifying the tissue elasticity and iteratively deforming the biomechanical model. Convergence occurred when each voxel was within 0.5 mm of the ground-truth deformation and 1 kPa of the ground-truth elasticity distribution. To analyze the feasibility of the model-guided approach, we present the results for regions of low ventilation, specifically, the apex. Results: The maximum apical boundary expansion was observed to be between 2 and 6 mm. Simulating this expansion within an apical lung model, it was observed that 100% of voxels converged within 0.5 mm of ground-truth deformation, while 91.8% converged within 1 kPa of the ground-truth elasticity distribution. A mean elasticity error of 0.6 kPa illustrates the high precision of our technique. Conclusion: By utilizing 4DCT lung data coupled with a biomechanical model, high precision lung elastography can be accurately performed, even in low ventilation regions of the lungs. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144087.« less

[Application of elastic registration based on Demons algorithm in cone beam CT].

PubMed

Pang, Haowen; Sun, Xiaoyang

2014-02-01

We applied Demons and accelerated Demons elastic registration algorithm in radiotherapy cone beam CT (CBCT) images, We provided software support for real-time understanding of organ changes during radiotherapy. We wrote a 3D CBCT image elastic registration program using Matlab software, and we tested and verified the images of two patients with cervical cancer 3D CBCT images for elastic registration, based on the classic Demons algorithm, minimum mean square error (MSE) decreased 59.7%, correlation coefficient (CC) increased 11.0%. While for the accelerated Demons algorithm, MSE decreased 40.1%, CC increased 7.2%. The experimental verification with two methods of Demons algorithm obtained the desired results, but the small difference appeared to be lack of precision, and the total registration time was a little long. All these problems need to be further improved for accuracy and reducing of time.

Advances in Radiotherapy for Glioblastoma

PubMed Central

Mann, Justin; Ramakrishna, Rohan; Magge, Rajiv; Wernicke, A. Gabriella

2018-01-01

External beam radiotherapy (RT) has long played a crucial role in the treatment of glioblastoma. Over the past several decades, significant advances in RT treatment and image-guidance technology have led to enormous improvements in the ability to optimize definitive and salvage treatments. This review highlights several of the latest developments and controversies related to RT, including the treatment of elderly patients, who continue to be a fragile and vulnerable population; potential salvage options for recurrent disease including reirradiation with chemotherapy; the latest imaging techniques allowing for more accurate and precise delineation of treatment volumes to maximize the therapeutic ratio of conformal RT; the ongoing preclinical and clinical data regarding the combination of immunotherapy with RT; and the increasing evidence of cancer stem-cell niches in the subventricular zone which may provide a potential target for local therapies. Finally, continued development on many fronts have allowed for modestly improved outcomes while at the same time limiting toxicity. PMID:29379468

Advances in Radiotherapy for Glioblastoma.

PubMed

Mann, Justin; Ramakrishna, Rohan; Magge, Rajiv; Wernicke, A Gabriella

2017-01-01

External beam radiotherapy (RT) has long played a crucial role in the treatment of glioblastoma. Over the past several decades, significant advances in RT treatment and image-guidance technology have led to enormous improvements in the ability to optimize definitive and salvage treatments. This review highlights several of the latest developments and controversies related to RT, including the treatment of elderly patients, who continue to be a fragile and vulnerable population; potential salvage options for recurrent disease including reirradiation with chemotherapy; the latest imaging techniques allowing for more accurate and precise delineation of treatment volumes to maximize the therapeutic ratio of conformal RT; the ongoing preclinical and clinical data regarding the combination of immunotherapy with RT; and the increasing evidence of cancer stem-cell niches in the subventricular zone which may provide a potential target for local therapies. Finally, continued development on many fronts have allowed for modestly improved outcomes while at the same time limiting toxicity.

Results of heavy ion radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castro, J.R.

1994-04-01

The potential of heavy ion therapy for clinical use in cancer therapy stems from the biological parameters of heavy charged particles, and their precise dose localization. Biologically, carbon, neon and other heavy ion beams (up to about silicon) are clinically useful in overcoming the radioresistance of hypoxic tumors, thus increasing biological effectiveness relative to low-LET x-ray or electron beams. Cells irradiated by heavy ions show less variation in cell-cycle related radiosensitivity and decreased repair of radiation injury. The physical parameters of these heavy charged particles allow precise delivery of high radiation doses to tumors while minimizing irradiation of normal tissues.more » Clinical use requires close interaction between radiation oncologists, medical physicists, accelerator physicists, engineers, computer scientists and radiation biologists.« less

Radiation techniques for esophageal cancer.

PubMed

Zhang, Minsi; Wu, Abraham J

2017-10-01

Radiotherapy plays a crucial role in the curative management of localized esophageal cancer, both as definitive and preoperative therapy. For definitive therapy, the standard radiation dose is 50.4 Gy in 28 fractions and should be delivered with concurrent chemotherapy. Chemoradiotherapy also has a wellestablished benefit in the preoperative setting, as established in the CROSS randomized trial. Radiation fields are typically generous, to account for subclinical extension of disease along the esophagus and to regional nodes. Three-dimensional conformal radiation is the current standard technique for esophageal cancer, though intensity-modulated radiation therapy is increasingly utilized and may improve the outcomes of esophageal radiotherapy by reducing radiation dose to critical normal tissues.

Performance analysis of a film dosimetric quality assurance procedure for IMRT with regard to the employment of quantitative evaluation methods.

PubMed

Winkler, Peter; Zurl, Brigitte; Guss, Helmuth; Kindl, Peter; Stuecklschweiger, Georg

2005-02-21

A system for dosimetric verification of intensity-modulated radiotherapy (IMRT) treatment plans using absolute calibrated radiographic films is presented. At our institution this verification procedure is performed for all IMRT treatment plans prior to patient irradiation. Therefore clinical treatment plans are transferred to a phantom and recalculated. Composite treatment plans are irradiated to a single film. Film density to absolute dose conversion is performed automatically based on a single calibration film. A software application encompassing film calibration, 2D registration of measurement and calculated distributions, image fusion, and a number of visual and quantitative evaluation utilities was developed. The main topic of this paper is a performance analysis for this quality assurance procedure, with regard to the specification of tolerance levels for quantitative evaluations. Spatial and dosimetric precision and accuracy were determined for the entire procedure, comprising all possible sources of error. The overall dosimetric and spatial measurement uncertainties obtained thereby were 1.9% and 0.8 mm respectively. Based on these results, we specified 5% dose difference and 3 mm distance-to-agreement as our tolerance levels for patient-specific quality assurance for IMRT treatments.

Optimize radiochemotherapy in pancreatic cancer: PARP inhibitors a new therapeutic opportunity.

PubMed

Porcelli, Letizia; Quatrale, Anna E; Mantuano, Paola; Leo, Maria G; Silvestris, Nicola; Rolland, Jean F; Carioggia, Enza; Lioce, Marco; Paradiso, Angelo; Azzariti, Amalia

2013-06-01

Cancer cells may use PARP enzymes and Homologous Recombination to repair single and double strand breaks caused by genotoxic insults. In this study, the PARP-1 inhibitor Rucaparib was utilized to increase the sensitivity to chemoradiotherapy treatment in BRCA-2-deficient and -proficient pancreatic cancer cells. We used the pancreatic cancer cell lines, Capan-1 with mutated BRCA-2 and Panc-1, AsPC-1 and MiaPaCa-2 with BRCA-1/2 wild type. Cells were treated with Rucaparib and/or radiotherapy (4-10 Gy) plus Gemcitabine then the capability to proliferate was evaluated by colony formation, cell counting and MTT assays. Flow cytometry, immunocytochemistry and western blotting were utilized to assess cell response to Rucaparib plus irradiation. The antitumour effectiveness of combining the PARP-1 inhibitor before, together and after radiotherapy evidenced the first as the optimal schedule in blocking cell growth. Pre-exposure to Rucaparib increased the cytotoxicity of Gemcitabine plus radiotherapy by heavily inducing the accumulation of cells in G2/M phase, impairing mitosis and finally inducing apoptosis and authophagy. The upregulation of p-Akt and downregulation of p53 were evidenced in MiaPaCa-2 which displayed replication stress features. For the first time, the rationale of using a PARP inhibitor as chemoradiosensitizer in pancreatic cancer models has been hypothesized and demonstrated. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

WE-FG-201-03: Lean Innovation Transforming Global Access to Best Practice Radiotherapy Treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feain, I.

Many low- and middle-income countries lack the resources and services to manage cancer, from screening and diagnosis to radiation therapy planning, treatment and quality assurance. The challenges in upgrading or introducing the needed services are enormous, and include severe shortages in equipment and trained staff. In this symposium, we will describe examples of technology and scientific research that have the potential to impact all these areas. These include: (1) the development of high-quality/low-cost colposcopes for cervical cancer screening, (2) the application of automated radiotherapy treatment planning to reduce staffing shortages, (3) the development of a novel radiotherapy treatment unit, andmore » (4) utilizing a cloud-based infrastructure to facilitate collaboration and QA. Learning Objectives: Understand some of the issues in cancer care in low- resource environments, including shortages in staff and equipment, and inadequate physical infrastructure for advanced radiotherapy. Understand the challenges in developing and deploying diagnostic and treatment devices and services for low-resource environments. Understand some of the emerging technological solutions for cancer management in LMICs. NCI; L. Court, NIH, Varian, Elekta; I. Feain, Ilana Feain is founder and CTO of Nano-X Pty Ltd.« less

WE-FG-201-04: Cloud-Based Collaboration for Radiotherapy Clinical Trials, Research and Training

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palta, J.

Many low- and middle-income countries lack the resources and services to manage cancer, from screening and diagnosis to radiation therapy planning, treatment and quality assurance. The challenges in upgrading or introducing the needed services are enormous, and include severe shortages in equipment and trained staff. In this symposium, we will describe examples of technology and scientific research that have the potential to impact all these areas. These include: (1) the development of high-quality/low-cost colposcopes for cervical cancer screening, (2) the application of automated radiotherapy treatment planning to reduce staffing shortages, (3) the development of a novel radiotherapy treatment unit, andmore » (4) utilizing a cloud-based infrastructure to facilitate collaboration and QA. Learning Objectives: Understand some of the issues in cancer care in low- resource environments, including shortages in staff and equipment, and inadequate physical infrastructure for advanced radiotherapy. Understand the challenges in developing and deploying diagnostic and treatment devices and services for low-resource environments. Understand some of the emerging technological solutions for cancer management in LMICs. NCI; L. Court, NIH, Varian, Elekta; I. Feain, Ilana Feain is founder and CTO of Nano-X Pty Ltd.« less

Cost analysis of cetuximab (Erbitux) plus radiotherapy (ERT) versus concomitant cisplatin plus radiotherapy (CRT) within an NHS oncology unit (single institution): a pilot study.

PubMed

Caroline, Brammer; Sundus, Yahya; Dawn, Dawson; Carol, Glaister; Susan, Merrick

2016-12-01

The aim of this feasibility study is to define the resource effectiveness of cetuximab vs cisplatin given concomitantly with radiotherapy for squamous cell carcinoma within a National Health Service clinical oncology unit. 20 patients with Stage 3 or 4 head and neck squamous cell cancers were randomized to receive either cetuximab with radiotherapy (ERT) or cisplatin with radiotherapy concurrent with external beam radiotherapy 70 Gy in 35 fractions on a 1 : 1 basis over a 12-month duration. The study compared the resource utilization of ERT vs cisplatin with radiotherapy taking into account drug costs, clinical management and the costs of managing treatment-related toxicity from first fraction of radiotherapy to 6 months after the completion of therapy. Outcome measures were quality of life (recorded at the entry, end of radiotherapy, 6 weeks post treatment and 6 months post treatment), admissions to hospital, delays to radiotherapy, locoregional control and survival. Total drug costs including cost of nutritional supplements for patients treated with cetuximab were £7407.45 compared with £3959.07 for patients treated with cisplatin. Unscheduled admissions for toxicity management were significantly more common in the ERT arm. Healthcare personnel spent significantly more time delivering unscheduled outpatient care for patients receiving cisplatin than for those receiving cetuximab (p = 0.01). No significant difference in the quality of life was suggested at baseline, 6 weeks and 6 months. The mean time to removal of percutaneous gastrostomy (PEG) after completion of radiotherapy was 49.7 weeks in the cisplatin arm and 18.5 weeks in the cetuximab arm (p = 0.04). There was a statistically significant difference in patient-reported use of PEG between the cisplatin and cetuximab arms at 6 months following completion of treatment (p = 0.04). At 21 months, overall survival was 80% in the cisplatin arm vs 50% in the cetuximab (p = 0.332), with disease-free survival being 80% in the cisplatin arm vs 40% in the cetuximab (p = 0.097). Cetuximab is still more expensive in simple drug cost terms than cisplatin when delivered with radiotherapy taking into account costs of drugs for toxicity management and nutritional supplements but other resource implications such as inpatient admission, time spent delivering unscheduled care and cost of additional investigations to manage toxicity for patients treated with cisplatin significantly reduce differential. The study suggested significant differences in patient-reported PEG use at 6 months and in time to PEG removal in favour of the cetuximab arm. Advances in knowledge: There is paucity of randomized data on cost analysis for cisplatin vs cetuximab radiotherapy; this trial informs on the cost analysis between the two approaches.

Effect of whole brain radiation on local cerebral glucose utilization in the rat.

PubMed

d'Avella, D; Cicciarello, R; Albiero, F; Mesiti, M; Gagliardi, M E; Russi, E; d'Aquino, A; Princi, P; d'Aquino, S

1991-04-01

We assessed, by means of the [14C]-2-deoxy-D-glucose autoradiography method, the effect of whole-brain x-radiation on local cerebral glucose utilization in the rat brain. Animals were exposed to conventional fractionation (200 +/- 4 cGy/day, 5 days/week; total dose, 4000 cGy). Metabolic experiments were made 2 to 3 weeks after completion of the radiation exposure. In comparison with control and sham-irradiated animals, cerebral metabolic activity was diffusely decreased after irradiation. Statistically significant decreases in metabolic activity were observed in 13 of 27 brain regions studied. In general, the brain areas with the highest basal metabolic rates showed the greatest percentage of decrease in glucose utilization. The concept that radiation suppresses glucose utilization before any morphological change takes place in the cell structures was the basis of this study. Metabolic alterations after irradiation may explain the syndrome of early delayed deterioration observed in humans after whole-brain radiotherapy. These studies have applications to observations made with the [18F]-fluorodeoxyglucose method in conjunction with positron emission tomographic scans in patients receiving radiation therapy for intracranial malignancies. The data reported here also have potential clinical implications for the evaluation of a risk/benefit ratio for radiotherapy in patients with benign neurosurgical diseases or children undergoing prophylactic treatment of the central nervous system.

Automated Information Extraction on Treatment and Prognosis for Non-Small Cell Lung Cancer Radiotherapy Patients: Clinical Study.

PubMed

Zheng, Shuai; Jabbour, Salma K; O'Reilly, Shannon E; Lu, James J; Dong, Lihua; Ding, Lijuan; Xiao, Ying; Yue, Ning; Wang, Fusheng; Zou, Wei

2018-02-01

In outcome studies of oncology patients undergoing radiation, researchers extract valuable information from medical records generated before, during, and after radiotherapy visits, such as survival data, toxicities, and complications. Clinical studies rely heavily on these data to correlate the treatment regimen with the prognosis to develop evidence-based radiation therapy paradigms. These data are available mainly in forms of narrative texts or table formats with heterogeneous vocabularies. Manual extraction of the related information from these data can be time consuming and labor intensive, which is not ideal for large studies. The objective of this study was to adapt the interactive information extraction platform Information and Data Extraction using Adaptive Learning (IDEAL-X) to extract treatment and prognosis data for patients with locally advanced or inoperable non-small cell lung cancer (NSCLC). We transformed patient treatment and prognosis documents into normalized structured forms using the IDEAL-X system for easy data navigation. The adaptive learning and user-customized controlled toxicity vocabularies were applied to extract categorized treatment and prognosis data, so as to generate structured output. In total, we extracted data from 261 treatment and prognosis documents relating to 50 patients, with overall precision and recall more than 93% and 83%, respectively. For toxicity information extractions, which are important to study patient posttreatment side effects and quality of life, the precision and recall achieved 95.7% and 94.5% respectively. The IDEAL-X system is capable of extracting study data regarding NSCLC chemoradiation patients with significant accuracy and effectiveness, and therefore can be used in large-scale radiotherapy clinical data studies. ©Shuai Zheng, Salma K Jabbour, Shannon E O'Reilly, James J Lu, Lihua Dong, Lijuan Ding, Ying Xiao, Ning Yue, Fusheng Wang, Wei Zou. Originally published in JMIR Medical Informatics (http://medinform.jmir.org), 01.02.2018.

The Utility of PET/CT in the Planning of External Radiation Therapy for Prostate Cancer.

PubMed

Calais, Jeremie; Cao, Minsong; Nickols, Nicholas G

2018-04-01

Radiotherapy and radical prostatectomy are the definitive treatment options for patients with localized prostate cancer. A rising level of prostate-specific antigen after radical prostatectomy indicates prostate cancer recurrence, and these patients may still be cured with salvage radiotherapy. To maximize chance for cure, the irradiated volumes should completely encompass the extent of disease. Therefore, accurate estimation of the location of disease is critical for radiotherapy planning in both the definitive and the salvage settings. Current first-line imaging for prostate cancer has limited sensitivity for detection of disease both at initial staging and at biochemical recurrence. Integration of PET into routine evaluation of prostate cancer patients may improve both staging accuracy and radiotherapy planning. 18 F-FDG PET/CT is now routinely used in radiation planning for several cancer types. However, 18 F-FDG PET/CT has low sensitivity for prostate cancer. Additional PET probes evaluated in prostate cancer include 18 F-sodium fluoride, 11 C-acetate, 11 C- or 18 F-choline, 18 F-fluciclovine, and 68 Ga- or 18 F-labeled ligands that bind prostate-specific membrane antigen (PSMA). PSMA ligands appear to be the most sensitive and specific but have not yet received Food and Drug Administration New Drug Application approval for use in the United States. Retrospective and prospective investigations suggest a potential major impact of PET/CT on prostate radiation treatment planning. Prospective trials randomizing patients to routine radiotherapy planning versus PET/CT-aided planning may show meaningful clinical outcomes. Prospective clinical trials evaluating the addition of 18 F-fluciclovine PET/CT for planning of salvage radiotherapy with clinical endpoints are under way. Prospective trials evaluating the clinical impact of PSMA PET/CT on prostate radiation planning are indicated. © 2018 by the Society of Nuclear Medicine and Molecular Imaging.

Treatment of hepatic metastases of colorectal cancer by robotic stereotactic radiation (Cyberknife ®).

PubMed

Peiffert, D; Baumann, A-S; Marchesi, V

2014-04-01

Cyberknife(®) is a dedicated stereotactic radiotherapy device. This new technology permits precise delivery of high dose gradient radiation therapy while sparing the surrounding organs at risk. Hepatic metastases of colorectal cancer (HMCRC) are an example of a lesion where treatment with Cyberknife(®) is indicated because they are located in a radio-sensitive organ and curative treatment is based on focal eradication (resection, radiofrequency ablation,...). The local control rate at one year is reported to be 70 to 100% depending on the study. Tolerance is excellent with less than a 5% rate of acute grade 3 or 4 side effects (nausea, vomiting, gastro-duodenal ulcer). The specific hepatotoxicity of radiotherapy, so-called radiation-induced liver disease (RILD), was found in only one study. Candidates for stereotactic radiotherapy are patients in whom disease is controlled except for intrahepatic disease with 1-3 hepatic metastases ≤ 6 cm in size who have contraindications for surgery, a WHO stage ≤ 2, a volume of healthy liver ≥ 700 cm(3) and normal liver function. It is actually a very simple treatment that results in very good local control with few contraindications. Its place in the management strategy of liver metastases needs further clarification. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Validation of a personalized dosimetric evaluation tool (Oedipe) for targeted radiotherapy based on the Monte Carlo MCNPX code

NASA Astrophysics Data System (ADS)

Chiavassa, S.; Aubineau-Lanièce, I.; Bitar, A.; Lisbona, A.; Barbet, J.; Franck, D.; Jourdain, J. R.; Bardiès, M.

2006-02-01

Dosimetric studies are necessary for all patients treated with targeted radiotherapy. In order to attain the precision required, we have developed Oedipe, a dosimetric tool based on the MCNPX Monte Carlo code. The anatomy of each patient is considered in the form of a voxel-based geometry created using computed tomography (CT) images or magnetic resonance imaging (MRI). Oedipe enables dosimetry studies to be carried out at the voxel scale. Validation of the results obtained by comparison with existing methods is complex because there are multiple sources of variation: calculation methods (different Monte Carlo codes, point kernel), patient representations (model or specific) and geometry definitions (mathematical or voxel-based). In this paper, we validate Oedipe by taking each of these parameters into account independently. Monte Carlo methodology requires long calculation times, particularly in the case of voxel-based geometries, and this is one of the limits of personalized dosimetric methods. However, our results show that the use of voxel-based geometry as opposed to a mathematically defined geometry decreases the calculation time two-fold, due to an optimization of the MCNPX2.5e code. It is therefore possible to envisage the use of Oedipe for personalized dosimetry in the clinical context of targeted radiotherapy.

Target margins in radiotherapy of prostate cancer

PubMed Central

Bauman, Glenn

2016-01-01

We reviewed the literature on the use of margins in radiotherapy of patients with prostate cancer, focusing on different options for image guidance (IG) and technical issues. The search in PubMed database was limited to include studies that involved external beam radiotherapy of the intact prostate. Post-prostatectomy studies, brachytherapy and particle therapy were excluded. Each article was characterized according to the IG strategy used: positioning on external marks using room lasers, bone anatomy and soft tissue match, usage of fiducial markers, electromagnetic tracking and adapted delivery. A lack of uniformity in margin selection among institutions was evident from the review. In general, introduction of pre- and in-treatment IG was associated with smaller planning target volume (PTV) margins, but there was a lack of definitive experimental/clinical studies providing robust information on selection of exact PTV values. In addition, there is a lack of comparative research regarding the cost–benefit ratio of the different strategies: insertion of fiducial markers or electromagnetic transponders facilitates prostate gland localization but at a price of invasive procedure; frequent pre-treatment imaging increases patient in-room time, dose and labour; online plan adaptation should improve radiation delivery accuracy but requires fast and precise computation. Finally, optimal protocols for quality assurance procedures need to be established. PMID:27377353

Growth Of High-Cost Intensity-Modulated Radiotherapy For Prostate Cancer Raises Concerns About Overuse

PubMed Central

Jacobs, Bruce L.; Zhang, Yun; Skolarus, Ted A.; Hollenbeck, Brent K.

2012-01-01

To study the impact of new, expensive, and unproven therapies to treat prostate cancer, we investigated the dissemination of intensity-modulated radiotherapy (IMRT). IMRT is an innovative treatment for prostate cancer that delivers higher doses of radiation with improved precision compared to alternative radiotherapies. We observed rapid adoption of this new treatment among men diagnosed with prostate cancer from 2001 through 2007, despite uncertainty about its relative effectiveness. We compared patient and disease characteristics of those receiving IMRT and the previous radiation standard of care, three-dimensional conformal therapy; assessed intermediate-term outcomes; and examined potential factors associated with the increased use of IMRT. We found that in the early period of IMRT adoption (2001–03) men with high-risk disease were more likely to receive IMRT, whereas after IMRT’s initial dissemination (2004–07) men with low-risk disease had fairly similar likelihoods of receiving IMRT as men with high-risk disease. This raises concerns about overtreatment, as well as considerable health care costs, because treatment with IMRT costs $15,000–$20,000 more than other standard therapies. As health care delivery reforms gain traction, policy makers must balance the promotion of new, yet unproven, technology with the risk of overuse. PMID:22492892

Improvement in toxicity in high risk prostate cancer patients treated with image-guided intensity-modulated radiotherapy compared to 3D conformal radiotherapy without daily image guidance.

PubMed

Sveistrup, Joen; af Rosenschöld, Per Munck; Deasy, Joseph O; Oh, Jung Hun; Pommer, Tobias; Petersen, Peter Meidahl; Engelholm, Svend Aage

2014-02-04

Image-guided radiotherapy (IGRT) facilitates the delivery of a very precise radiation dose. In this study we compare the toxicity and biochemical progression-free survival between patients treated with daily image-guided intensity-modulated radiotherapy (IG-IMRT) and 3D conformal radiotherapy (3DCRT) without daily image guidance for high risk prostate cancer (PCa). A total of 503 high risk PCa patients treated with radiotherapy (RT) and endocrine treatment between 2000 and 2010 were retrospectively reviewed. 115 patients were treated with 3DCRT, and 388 patients were treated with IG-IMRT. 3DCRT patients were treated to 76 Gy and without daily image guidance and with 1-2 cm PTV margins. IG-IMRT patients were treated to 78 Gy based on daily image guidance of fiducial markers, and the PTV margins were 5-7 mm. Furthermore, the dose-volume constraints to both the rectum and bladder were changed with the introduction of IG-IMRT. The 2-year actuarial likelihood of developing grade > = 2 GI toxicity following RT was 57.3% in 3DCRT patients and 5.8% in IG-IMRT patients (p < 0.001). For GU toxicity the numbers were 41.8% and 29.7%, respectively (p = 0.011). On multivariate analysis, 3DCRT was associated with a significantly increased risk of developing grade > = 2 GI toxicity compared to IG-IMRT (p < 0.001, HR = 11.59 [CI: 6.67-20.14]). 3DCRT was also associated with an increased risk of developing GU toxicity compared to IG-IMRT.The 3-year actuarial biochemical progression-free survival probability was 86.0% for 3DCRT and 90.3% for IG-IMRT (p = 0.386). On multivariate analysis there was no difference in biochemical progression-free survival between 3DCRT and IG-IMRT. The difference in toxicity can be attributed to the combination of the IMRT technique with reduced dose to organs-at-risk, daily image guidance and margin reduction.

Cost analysis of cetuximab (Erbitux) plus radiotherapy (ERT) versus concomitant cisplatin plus radiotherapy (CRT) within an NHS oncology unit (single institution): a pilot study

PubMed Central

Sundus, Yahya; Dawn, Dawson; Carol, Glaister; Susan, Merrick

2016-01-01

Objective: The aim of this feasibility study is to define the resource effectiveness of cetuximab vs cisplatin given concomitantly with radiotherapy for squamous cell carcinoma within a National Health Service clinical oncology unit. Methods: 20 patients with Stage 3 or 4 head and neck squamous cell cancers were randomized to receive either cetuximab with radiotherapy (ERT) or cisplatin with radiotherapy concurrent with external beam radiotherapy 70 Gy in 35 fractions on a 1 : 1 basis over a 12-month duration. The study compared the resource utilization of ERT vs cisplatin with radiotherapy taking into account drug costs, clinical management and the costs of managing treatment-related toxicity from first fraction of radiotherapy to 6 months after the completion of therapy. Outcome measures were quality of life (recorded at the entry, end of radiotherapy, 6 weeks post treatment and 6 months post treatment), admissions to hospital, delays to radiotherapy, locoregional control and survival. Results: Total drug costs including cost of nutritional supplements for patients treated with cetuximab were £7407.45 compared with £3959.07 for patients treated with cisplatin. Unscheduled admissions for toxicity management were significantly more common in the ERT arm. Healthcare personnel spent significantly more time delivering unscheduled outpatient care for patients receiving cisplatin than for those receiving cetuximab (p = 0.01). No significant difference in the quality of life was suggested at baseline, 6 weeks and 6 months. The mean time to removal of percutaneous gastrostomy (PEG) after completion of radiotherapy was 49.7 weeks in the cisplatin arm and 18.5 weeks in the cetuximab arm (p = 0.04). There was a statistically significant difference in patient-reported use of PEG between the cisplatin and cetuximab arms at 6 months following completion of treatment (p = 0.04). At 21 months, overall survival was 80% in the cisplatin arm vs 50% in the cetuximab (p = 0.332), with disease-free survival being 80% in the cisplatin arm vs 40% in the cetuximab (p = 0.097). Conclusion: Cetuximab is still more expensive in simple drug cost terms than cisplatin when delivered with radiotherapy taking into account costs of drugs for toxicity management and nutritional supplements but other resource implications such as inpatient admission, time spent delivering unscheduled care and cost of additional investigations to manage toxicity for patients treated with cisplatin significantly reduce differential. The study suggested significant differences in patient-reported PEG use at 6 months and in time to PEG removal in favour of the cetuximab arm. Advances in knowledge: There is paucity of randomized data on cost analysis for cisplatin vs cetuximab radiotherapy; this trial informs on the cost analysis between the two approaches. PMID:27734748

A dosimetric phantom study of thoracic radiotherapy based on three-dimensional modeling of mediastinal lymph nodes

PubMed Central

Zhang, Ji-Bin; Zhao, Li-Rong; Cui, Tian-Xiang; Chen, Xie-Wan; Yang, Qiao; Zhou, Yi-Bing; Chen, Zheng-Tang; Zhang, Shao-Xiang; Sun, Jian-Guo

2018-01-01

The aim of the present study was to investigate the optimal strategy and dosimetric measurement of thoracic radiotherapy based on three-dimensional (3D) modeling of mediastinal lymph nodes (MLNs). A 3D model of MLNs was constructed from a Chinese Visible Human female dataset. Image registration and fusion between reconstructed MLNs and original chest computed tomography (CT) images was conducted in the Eclipse™ treatment planning system (TPS). There were three plans, including 3D conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT), which were designed based on 10 cases of simulated lung lesions (SLLs) and MLNs. The quality of these plans was evaluated via examining indexes, including conformity index (CI), homogeneity index and clinical target volume (CTV) coverage. Dose-volume histogram analysis was performed on SLL, MLNs and organs at risk (OARs). A Chengdu Dosimetric Phantom (CDP) was then drilled at specific MLNs according to 20 patients with thoracic tumors and of a medium-build. These plans were repeated on fused MLNs and CDP CT images in the Eclipse™ TPS. Radiation doses at the SLLs and MLNs of the CDP were measured and compared with calculated doses. The established 3D MLN model demonstrated the spatial location of MLNs and adjacent structures. Precise image registration and fusion were conducted between reconstructed MLNs and the original chest CT or CDP CT images. IMRT demonstrated greater values in CI, CTV coverage and OAR (lungs and spinal cord) protection, compared with 3D-CRT and VMAT (P<0.05). The deviation between the measured and calculated doses was within ± 10% at SLL, and at the 2R and 7th MLN stations. In conclusion, the 3D MLN model can benefit plan optimization and dosimetric measurement of thoracic radiotherapy, and when combined with CDP, it may provide a tool for clinical dosimetric monitoring. PMID:29556300

Characterization of a synthetic single crystal diamond detector for dosimetry in spatially fractionated synchrotron x-ray fields.

PubMed

Livingstone, Jayde; Stevenson, Andrew W; Butler, Duncan J; Häusermann, Daniel; Adam, Jean-François

2016-07-01

Modern radiotherapy modalities often use small or nonstandard fields to ensure highly localized and precise dose delivery, challenging conventional clinical dosimetry protocols. The emergence of preclinical spatially fractionated synchrotron radiotherapies with high dose-rate, sub-millimetric parallel kilovoltage x-ray beams, has pushed clinical dosimetry to its limit. A commercially available synthetic single crystal diamond detector designed for small field dosimetry has been characterized to assess its potential as a dosimeter for synchrotron microbeam and minibeam radiotherapy. Experiments were carried out using a synthetic diamond detector on the imaging and medical beamline (IMBL) at the Australian Synchrotron. The energy dependence of the detector was characterized by cross-referencing with a calibrated ionization chamber in monoenergetic beams in the energy range 30-120 keV. The dose-rate dependence was measured in the range 1-700 Gy/s. Dosimetric quantities were measured in filtered white beams, with a weighted mean energy of 95 keV, in broadbeam and spatially fractionated geometries, and compared to reference dosimeters. The detector exhibits an energy dependence; however, beam quality correction factors (kQ) have been measured for energies in the range 30-120 keV. The kQ factor for the weighted mean energy of the IMBL radiotherapy spectrum, 95 keV, is 1.05 ± 0.09. The detector response is independent of dose-rate in the range 1-700 Gy/s. The percentage depth dose curves measured by the diamond detector were compared to ionization chambers and agreed to within 2%. Profile measurements of microbeam and minibeam arrays were performed. The beams are well resolved and the full width at halfmaximum agrees with the nominal width of the beams. The peak to valley dose ratio (PVDR) calculated from the profiles at various depths in water agrees within experimental error with PVDR calculations from Gafchromic film data. The synthetic diamond detector is now well characterized and will be used to develop an experimental dosimetry protocol for spatially fractionated synchrotron radiotherapy.

Stereotactic radiosurgery versus stereotactic radiotherapy for patients with vestibular schwannoma: a Leksell Gamma Knife Society 2000 debate.

PubMed

Linskey, M E

2000-12-01

By definition, the term "radiosurgery" refers to the delivery of a therapeutic radiation dose in a single fraction, not simply the use of stereotaxy. Multiple-fraction delivery is better termed "stereotactic radiotherapy." There are compelling radiobiological principles supporting the biological superiority of single-fraction radiation for achieving an optimal therapeutic response for the slowly proliferating, late-responding, tissue of a schwannoma. It is axiomatic that complication avoidance requires precise three-dimensional conformality between treatment and tumor volumes. This degree of conformality can only be achieved through complex multiisocenter planning. Alternative radiosurgery devices are generally limited to delivering one to four isocenters in a single treatment session. Although they can reproduce dose plans similar in conformality to early gamma knife dose plans by using a similar number of isocenters, they cannot reproduce the conformality of modern gamma knife plans based on magnetic resonance image-targeted localization and five to 30 isocenters. A disturbing trend is developing in which institutions without nongamma knife radiosurgery (GKS) centers are championing and/or shifting to hypofractionated stereotactic radiotherapy for vestibular schwannomas. This trend appears to be driven by a desire to reduce complication rates to compete with modern GKS results by using complex multiisocenter planning. Aggressive advertising and marketing from some of these centers even paradoxically suggests biological superiority of hypofractionation approaches over single-dose radiosurgery for vestibular schwannomas. At the same time these centers continue to use the term radiosurgery to describe their hypofractionated radiotherapy approach in an apparent effort to benefit from a GKS "halo effect." It must be reemphasized that as neurosurgeons our primary duty is to achieve permanent tumor control for our patients and not to eliminate complications at the expense of potential late recurrence. The answer to minimizing complications while maintaining maximum tumor control is improved conformality of radiosurgery dose planning and not resorting to homeopathic radiosurgery doses or hypofractionation radiotherapy schemes.

Stereotactic radiosurgery versus stereotactic radiotherapy for patients with vestibular schwannoma: a Leksell Gamma Knife Society 2000 debate.

PubMed

Linskey, Mark E

2013-12-01

By definition, the term "radiosurgery" refers to the delivery of a therapeutic radiation dose in a single fraction, not simply the use of stereotaxy. Multiple-fraction delivery is better termed "stereotactic radiotherapy." There are compelling radiobiological principles supporting the biological superiority of single-fraction radiation for achieving an optimal therapeutic response for the slowly proliferating, late-responding, tissue of a schwannoma. It is axiomatic that complication avoidance requires precise three-dimensional conformality between treatment and tumor volumes. This degree of conformality can only be achieved through complex multiisocenter planning. Alternative radiosurgery devices are generally limited to delivering one to four isocenters in a single treatment session. Although they can reproduce dose plans similar in conformality to early gamma knife dose plans by using a similar number of isocenters, they cannot reproduce the conformality of modern gamma knife plans based on magnetic resonance image--targeted localization and five to 30 isocenters. A disturbing trend is developing in which institutions without nongamma knife radiosurgery (GKS) centers are championing and/or shifting to hypofractionated stereotactic radiotherapy for vestibular schwannomas. This trend appears to be driven by a desire to reduce complication rates to compete with modern GKS results by using complex multiisocenter planning. Aggressive advertising and marketing from some of these centers even paradoxically suggests biological superiority of hypofractionation approaches over single-dose radiosurgery for vestibular schwannomas. At the same time these centers continue to use the term radiosurgery to describe their hypofractionated radiotherapy approach in an apparent effort to benefit from a GKS "halo effect." It must be reemphasized that as neurosurgeons our primary duty is to achieve permanent tumor control for our patients and not to eliminate complications at the expense of potential late recurrence. The answer to minimizing complications while maintaining maximum tumor control is improved conformality of radiosurgery dose planning and not resorting to homeopathic radiosurgery doses or hypofractionation radiotherapy schemes.

Magnetic resonance imaging in precision radiation therapy for lung cancer

PubMed Central

Bainbridge, Hannah; Salem, Ahmed; Tijssen, Rob H. N.; Dubec, Michael; Wetscherek, Andreas; Van Es, Corinne; Belderbos, Jose; Faivre-Finn, Corinne

2017-01-01

Radiotherapy remains the cornerstone of curative treatment for inoperable locally advanced lung cancer, given concomitantly with platinum-based chemotherapy. With poor overall survival, research efforts continue to explore whether integration of advanced radiation techniques will assist safe treatment intensification with the potential for improving outcomes. One advance is the integration of magnetic resonance imaging (MRI) in the treatment pathway, providing anatomical and functional information with excellent soft tissue contrast without exposure of the patient to radiation. MRI may complement or improve the diagnostic staging accuracy of F-18 fluorodeoxyglucose position emission tomography and computerized tomography imaging, particularly in assessing local tumour invasion and is also effective for identification of nodal and distant metastatic disease. Incorporating anatomical MRI sequences into lung radiotherapy treatment planning is a novel application and may improve target volume and organs at risk delineation reproducibility. Furthermore, functional MRI may facilitate dose painting for heterogeneous target volumes and prediction of normal tissue toxicity to guide adaptive strategies. MRI sequences are rapidly developing and although the issue of intra-thoracic motion has historically hindered the quality of MRI due to the effect of motion, progress is being made in this field. Four-dimensional MRI has the potential to complement or supersede 4D CT and 4D F-18-FDG PET, by providing superior spatial resolution. A number of MR-guided radiotherapy delivery units are now available, combining a radiotherapy delivery machine (linear accelerator or cobalt-60 unit) with MRI at varying magnetic field strengths. This novel hybrid technology is evolving with many technical challenges to overcome. It is anticipated that the clinical benefits of MR-guided radiotherapy will be derived from the ability to adapt treatment on the fly for each fraction and in real-time, using ‘beam-on’ imaging. The lung tumour site group of the Atlantic MR-Linac consortium is working to generate a challenging MR-guided adaptive workflow for multi-institution treatment intensification trials in this patient group. PMID:29218271

Visibility of an iron-containing fiducial marker in magnetic resonance imaging for high-precision external beam prostate radiotherapy.

PubMed

Tanaka, Osamu; Komeda, Hisao; Hirose, Shigeki; Taniguchi, Takuya; Ono, Kousei; Matsuo, Masayuki

2017-11-29

Visualization of fiducial gold markers is critical for registration on computed tomography (CT) and magnetic resonance imaging (MRI) for imaging-guided radiotherapy. Although larger markers provide better visualization on MRI, they tend to generate artifacts on CT. MRI is strongly influenced by the presence of metals, such as iron, in the body. Here we compared efficacies of a 0.5% iron-containing gold marker (GM) and a traditional non-iron-containing marker. Twenty-seven patients underwent CT/MRI fusion-based intensity-modulated radiotherapy. Markers were placed by urologists under local anesthesia. Gold Anchor (GA; diameter: 0.28 mm; length: 10 mm), an iron-containing marker, was placed on the right side of the prostate using a 22-G needle and VISICOIL (VIS; diameter: 0.35 mm; length: 10 mm), a non-iron-containing marker, was placed on the left side using a 19-G needle. T2*-weighted images MRI sequences were obtained. Two radiation oncologists and a radiation technologist evaluated and assigned scores for visual quality on a five-point scale (1, poor; 5, best visibility). Artifact generation on CT was slightly greater with GA than with VIS. The mean marker visualization scores on MRI of all three observers were significantly superior for GA than for VIS (3.5 vs 3.2, 3.9 vs 3.2, and 4.0 vs 2.9). The actual size of the spherical GA was about 2 mm in diameter, but the signal void on MRI was approximately 5 mm. Although both markers were well visualized and can be recommended clinically, the results suggest that GA has some subtle advantages for quantitative visualization that could prove useful in certain situations of stereotactic body radiotherapy and intensity-modulated radiotherapy. © 2017 John Wiley & Sons Australia, Ltd.

Concurrent chemoradiotherapy versus radiotherapy alone for locoregionally advanced nasopharyngeal carcinoma in the era of intensity-modulated radiotherapy: a meta-analysis.

PubMed

He, Yan; Guo, Tao; Guan, Hui; Wang, Jingjing; Sun, Yu; Peng, Xingchen

2018-01-01

In this study, we attempted to compare the efficacy and toxicity of concurrent chemoradiotherapy (CCRT) with radiotherapy alone (RT) for locoregionally advanced nasopharyngeal carcinoma (LANPC) in the era of intensity-modulated radiotherapy (IMRT) by meta-analysis. We searched databases, and all randomized controlled trials meeting the inclusion criteria were utilized for a meta-analysis with RevMan 5.3 based on the Cochrane methodology. Fifteen studies were found suitable based on the inclusion criteria. CCRT not only significantly improved the overall response rate (risk ratio [RR]=0.53, 95% CI 0.43-0.66) and the complete response rate (RR=0.60, 95% CI 0.51-0.71) but also contributed to longer overall survival. The incidence of grade 3-4 adverse events from CCRT group increased in hematologic toxicity (RR 2.25, 95% CI 1.54-3.29), radiation-induced oral mucositis (RR 1.64, 95% CI 1.14-2.35), and radiodermatitis (RR 1.80, 95% CI 1.13-2.88). Compared with IMRT alone, CCRT provided survival benefit with acceptable toxicity in patients with LANPC. However, we need multicenter randomized controlled trials and long-term follow-up to evaluate the eventual efficacy and toxicity of concurrent chemotherapy plus IMRT.

Mitochondrial stress controls the radiosensitivity of the oxygen effect: Implications for radiotherapy.

PubMed

Richardson, Richard B; Harper, Mary-Ellen

2016-04-19

It has been more than 60 years since the discovery of the oxygen effect that empirically demonstrates the direct association between cell radiosensitivity and oxygen tension, important parameters in radiotherapy. Yet the mechanisms underlying this principal tenet of radiobiology are poorly understood. Better understanding of the oxygen effect may explain difficulty in eliminating hypoxic tumor cells, a major cause of regrowth after therapy. Our analysis utilizes the Howard-Flanders and Alper formula, which describes the relationship of radiosensitivity with oxygen tension. Here, we assign and qualitatively assess the relative contributions of two important mechanisms. The first mechanism involves the emission of reactive oxygen species from the mitochondrial electron transport chain, which increases with oxygen tension. The second mechanism is related to an energy and repair deficit, which increases with hypoxia. Following a radiation exposure, the uncoupling of the oxidative phosphorylation system (proton leak) in mitochondria lowers the emission of reactive oxygen species which has implications for fractionated radiotherapy, particularly of hypoxic tumors. Our analysis shows that, in oxygenated tumor and normal cells, mitochondria, rather than the nucleus, are the primary loci of radiotherapy effects, especially for low linear energy transfer radiation. Therefore, the oxygen effect can be explained by radiation-induced effects in mitochondria that generate reactive oxygen species, which in turn indirectly target nuclear DNA.

Visualization of gene expression in the live subject using the Na/I symporter as a reporter gene: applications in biotherapy.

PubMed

Baril, Patrick; Martin-Duque, Pilar; Vassaux, Georges

2010-02-01

Biotherapies involve the utilization of antibodies, genetically modified viruses, bacteria or cells for therapeutic purposes. Molecular imaging has the potential to provide unique information that will guarantee their biosafety in humans and provide a rationale for the future development of new generations of reagents. In this context, non-invasive imaging of gene expression is an attractive prospect, allowing precise, spacio-temporal measurements of gene expression in longitudinal studies involving gene transfer vectors. With the emergence of cell therapies in regenerative medicine, it is also possible to track cells injected into subjects. In this context, the Na/I symporter (NIS) has been used in preclinical studies. Associated with a relevant radiotracer ((123)I(-), (124)I(-), (99m)TcO4(-)), NIS can be used to monitor gene transfer and the spread of selectively replicative viruses in tumours as well as in cells with a therapeutic potential. In addition to its imaging potential, NIS can be used as a therapeutic transgene through its ability to concentrate therapeutic doses of radionuclides in target cells. This dual property has applications in cancer treatment and could also be used to eradicate cells with therapeutic potential in the case of adverse events. Through experience acquired in preclinical studies, we can expect that non-invasive molecular imaging using NIS as a transgene will be pivotal for monitoring in vivo the exact distribution and pharmacodynamics of gene expression in a precise and quantitative way. This review highlights the applications of NIS in biotherapy, with a particular emphasis on image-guided radiotherapy, monitoring of gene and vector biodistribution and trafficking of stem cells.

Brachytherapy Boost Utilization and Survival in Unfavorable-risk Prostate Cancer.

PubMed

Johnson, Skyler B; Lester-Coll, Nataniel H; Kelly, Jacqueline R; Kann, Benjamin H; Yu, James B; Nath, Sameer K

2017-11-01

There are limited comparative survival data for prostate cancer (PCa) patients managed with a low-dose rate brachytherapy (LDR-B) boost and dose-escalated external-beam radiotherapy (DE-EBRT) alone. To compare overall survival (OS) for men with unfavorable PCa between LDR-B and DE-EBRT groups. Using the National Cancer Data Base, we identified men with unfavorable PCa treated between 2004 and 2012 with androgen suppression (AS) and either EBRT followed by LDR-B or DE-EBRT (75.6-86.4Gy). Treatment selection was evaluated using logistic regression and annual percentage proportions. OS was analyzed using the Kaplan-Meier method, log-rank test, Cox proportional hazards, and propensity score matching. We identified 25038 men between 2004 and 2012, during which LDR-B boost utilization decreased from 29% to 14%. LDR-B was associated with better OS on univariate (7-yr OS: 82% vs 73%; p<0.001) and multivariate analyses (hazard ratio [HR] 0.70, 95% confidence interval [CI] 0.64-0.77). Propensity score matching verified an OS benefit associated with LDR-B boost (HR 0.74, 95% CI 0.66-0.89). The OS benefit of LDR-B boost persisted when limited to men aged <60 yr with no comorbidities. On subset analysis, there was no interaction between treatment and age, risk group, or radiation dose. Limitations include the retrospective design, nonrandomized selection bias, and the absence of treatment toxicity, hormone duration, and cancer-specific outcomes. Between 2004 and 2012, LDR-B boost utilization declined and was associated with better OS compared to DE-EBRT alone. LDR-B boost is probably the ideal treatment option for men with unfavorable PCa, pending long-term results of randomized trials. We compared radiotherapy utilization and survival for prostate cancer (PCa) patients using a national database. We found that low-dose rate brachytherapy (LDR-B) boost, a method being used less frequently, was associated with better overall survival when compared to dose-escalated external-beam radiotherapy alone for men with unfavorable PCa. Randomized trials are needed to confirm that LDR-B boost is the ideal treatment. Copyright © 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Clinical Positioning Accuracy for Multisession Stereotactic Radiotherapy With the Gamma Knife Perfexion

PubMed Central

Young, Lori A.; Phillips, Mark H.; Cheung, Michael; Halasz, Lia M.; Rockhill, Jason K.

2017-01-01

Multisession stereotactic radiation therapy is increasingly being seen as a preferred option for intracranial diseases in close proximity to critical structures and for larger target volumes. The objective of this study is to investigate the reproducibility of the Extend system from Elekta. A retrospective review was conducted for all patients treated with multisession Gamma Knife between July 2010 and June 2015, including both malignant and benign lesions. Eighty-four patients were treated in this 5-year span. The average residual daily setup uncertainty was 0.48 (0.19) mm. We compare measurements of setup uncertainty from the Extend system to measurements performed with a linac-based approach previously used in our center. The Extend system has significantly reduced setup uncertainty for fractionated intracranial treatments at our institution. Positive results were observed in a small population of edentulous patients. The Extend system compares favorably with other approaches to delivering intracranial stereotactic radiotherapy and is a robust, simple-to-use, and precise method for treating multisession intracranial lesions. PMID:28514899

A Noninvasive Body Setup Method for Radiotherapy by Using a Multimodal Image Fusion Technique

PubMed Central

Zhang, Jie; Chen, Yunxia; Wang, Chenchen; Chu, Kaiyue; Jin, Jianhua; Huang, Xiaolin; Guan, Yue; Li, Weifeng

2017-01-01

Purpose: To minimize the mismatch error between patient surface and immobilization system for tumor location by a noninvasive patient setup method. Materials and Methods: The method, based on a point set registration, proposes a shift for patient positioning by integrating information of the computed tomography scans and that of optical surface landmarks. An evaluation of the method included 3 areas: (1) a validation on a phantom by estimating 100 known mismatch errors between patient surface and immobilization system. (2) Five patients with pelvic tumors were considered. The tumor location errors of the method were measured using the difference between the proposal shift of cone-beam computed tomography and that of our method. (3) The collected setup data from the evaluation of patients were compared with the published performance data of other 2 similar systems. Results: The phantom verification results showed that the method was capable of estimating mismatch error between patient surface and immobilization system in a precision of <0.22 mm. For the pelvic tumor, the method had an average tumor location error of 1.303, 2.602, and 1.684 mm in left–right, anterior–posterior, and superior–inferior directions, respectively. The performance comparison with other 2 similar systems suggested that the method had a better positioning accuracy for pelvic tumor location. Conclusion: By effectively decreasing an interfraction uncertainty source (mismatch error between patient surface and immobilization system) in radiotherapy, the method can improve patient positioning precision for pelvic tumor. PMID:29333959

Planning magnetic resonance imaging for prostate cancer intensity-modulated radiation therapy: Impact on target volumes, radiotherapy dose and androgen deprivation administration.

PubMed

Horsley, Patrick J; Aherne, Noel J; Edwards, Grace V; Benjamin, Linus C; Wilcox, Shea W; McLachlan, Craig S; Assareh, Hassan; Welshman, Richard; McKay, Michael J; Shakespeare, Thomas P

2015-03-01

Magnetic resonance imaging (MRI) scans are increasingly utilized for radiotherapy planning to contour the primary tumors of patients undergoing intensity-modulated radiation therapy (IMRT). These scans may also demonstrate cancer extent and may affect the treatment plan. We assessed the impact of planning MRI detection of extracapsular extension, seminal vesicle invasion, or adjacent organ invasion on the staging, target volume delineation, doses, and hormonal therapy of patients with prostate cancer undergoing IMRT. The records of 509 consecutive patients with planning MRI scans being treated with IMRT for prostate cancer between January 2010 and July 2012 were retrospectively reviewed. Tumor staging and treatment plans before and after MRI were compared. Of the 509 patients, 103 (20%) were upstaged and 44 (9%) were migrated to a higher risk category as a result of findings at MRI. In 94 of 509 patients (18%), the MRI findings altered management. Ninety-four of 509 patients (18%) had a change to their clinical target volume (CTV) or treatment technique, and in 41 of 509 patients (8%) the duration of hormone therapy was changed because of MRI findings. The use of radiotherapy planning MRI altered CTV design, dose and/or duration of androgen deprivation in 18% of patients in this large, single institution series of men planned for dose-escalated prostate IMRT. This has substantial implications for radiotherapy target volumes and doses, as well as duration of androgen deprivation. Further research is required to investigate whether newer MRI techniques can simultaneously fulfill staging and radiotherapy contouring roles. © 2014 Wiley Publishing Asia Pty Ltd.

Radionuclide 131I-labeled multifunctional dendrimers for targeted SPECT imaging and radiotherapy of tumors

NASA Astrophysics Data System (ADS)

Zhu, Jingyi; Zhao, Lingzhou; Cheng, Yongjun; Xiong, Zhijuan; Tang, Yueqin; Shen, Mingwu; Zhao, Jinhua; Shi, Xiangyang

2015-10-01

We report the synthesis, characterization, and utilization of radioactive 131I-labeled multifunctional dendrimers for targeted single-photon emission computed tomography (SPECT) imaging and radiotherapy of tumors. In this study, amine-terminated poly(amidoamine) dendrimers of generation 5 (G5.NH2) were sequentially modified with 3-(4'-hydroxyphenyl)propionic acid-OSu (HPAO) and folic acid (FA) linked with polyethylene glycol (PEG), followed by acetylation modification of the dendrimer remaining surface amines and labeling of radioactive iodine-131 (131I). The generated multifunctional 131I-G5.NHAc-HPAO-PEG-FA dendrimers were characterized via different methods. We show that prior to 131I labeling, the G5.NHAc-HPAO-PEG-FA dendrimers conjugated with approximately 9.4 HPAO moieties per dendrimer are noncytotoxic at a concentration up to 20 μM and are able to target cancer cells overexpressing FA receptors (FAR), thanks to the modified FA ligands. In the presence of a phenol group, radioactive 131I is able to be efficiently labeled onto the dendrimer platform with good stability and high radiochemical purity, and render the platform with an ability for targeted SPECT imaging and radiotherapy of an FAR-overexpressing xenografted tumor model in vivo. The designed strategy to use the facile dendrimer nanotechnology may be extended to develop various radioactive theranostic nanoplatforms for targeted SPECT imaging and radiotherapy of different types of cancer.We report the synthesis, characterization, and utilization of radioactive 131I-labeled multifunctional dendrimers for targeted single-photon emission computed tomography (SPECT) imaging and radiotherapy of tumors. In this study, amine-terminated poly(amidoamine) dendrimers of generation 5 (G5.NH2) were sequentially modified with 3-(4'-hydroxyphenyl)propionic acid-OSu (HPAO) and folic acid (FA) linked with polyethylene glycol (PEG), followed by acetylation modification of the dendrimer remaining surface amines and labeling of radioactive iodine-131 (131I). The generated multifunctional 131I-G5.NHAc-HPAO-PEG-FA dendrimers were characterized via different methods. We show that prior to 131I labeling, the G5.NHAc-HPAO-PEG-FA dendrimers conjugated with approximately 9.4 HPAO moieties per dendrimer are noncytotoxic at a concentration up to 20 μM and are able to target cancer cells overexpressing FA receptors (FAR), thanks to the modified FA ligands. In the presence of a phenol group, radioactive 131I is able to be efficiently labeled onto the dendrimer platform with good stability and high radiochemical purity, and render the platform with an ability for targeted SPECT imaging and radiotherapy of an FAR-overexpressing xenografted tumor model in vivo. The designed strategy to use the facile dendrimer nanotechnology may be extended to develop various radioactive theranostic nanoplatforms for targeted SPECT imaging and radiotherapy of different types of cancer. Electronic supplementary information (ESI) available: Part of the experimental details and additional experimental results. See DOI: 10.1039/c5nr05585g

A review of stereotactic body radiotherapy – is volumetric modulated arc therapy the answer?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sapkaroski, Daniel, E-mail: daniel.sapkaroski@gmail.com; Osborne, Catherine; Knight, Kellie A

2015-06-15

Stereotactic body radiotherapy (SBRT) is a high precision radiotherapy technique used for the treatment of small to moderate extra-cranial tumours. Early studies utilising SBRT have shown favourable outcomes. However, major disadvantages of static field SBRT include long treatment times and toxicity complications. Volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT) may potentially mitigate these disadvantages. This review aims to assess the feasibility of emerging VMAT and IMRT-based SBRT treatment techniques and qualify which offers the best outcome for patients, whilst identifying any emerging and advantageous SBRT planning trends. A review and synthesis of data from current literature upmore » to September 2013 was conducted on EMBASE, Medline, PubMed, Science Direct, Proquest central, Google Scholar and the Cochrane Database of Systematic reviews. Only full text papers comparing VMAT and or IMRT and or Static SBRT were included. Ten papers were identified that evaluated the results of VMAT/IMRT SBRT. Five related to medically inoperable stage 1 and 2 non-small-cell lung cancer (NSCLC), three to spinal metastasis, one related to abdominal lymph node malignancies, with the final one looking at pancreatic adenocarcinoma. Overall treatment times with VMAT were reduced by 66–70% for lung, 46–58% for spine, 42% and 21% for lymph node and pancreatic metastasis respectively, planning constraints were met with several studies showing improved organs at risk sparing with IMRT/VMAT to static SBRT. Both IMRT and VMAT were able to meet all planning constraints in the studies reviewed, with VMAT offering the greatest treatment efficiency. Early clinical outcomes with VMAT and IMRT SBRT have demonstrated excellent local control and favourable survival outcomes.« less

Quality Control of Involved Field Radiotherapy in Patients With Early-Favorable (HD10) and Early-Unfavorable (HD11) Hodgkin's Lymphoma: An Analysis of the German Hodgkin Study Group

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eich, Hans Theodor; Engenhart-Cabillic, Rita; Hansemann, Katja

2008-08-01

Purpose: The German Hodgkin Study Group (GHSG) set up a radiotherapy (RT) reference center within the Department of Radiation Oncology at University of Cologne to undertake quality assurance of the group's clinical studies. In the HD10 trial (early-favorable stages) and HD11 trial (early-unfavorable stages) all patients received involved field (IF)-RT (30 Gy vs. 20 Gy) within a combined-modality approach. For these patients a central prospective review of all diagnostic imaging was performed by expert radiation oncologists to control disease extension and to define IF treatment volume. Methods and Materials: On the basis of simulation films, verification films, and radiotherapy casemore » report form (CRF) an expert panel evaluated retrospectively the adequacy of irradiated IF treatment portals according to the RT prescription, applied radiation doses, treatment time, and technical parameters. Results: Between 1999 and 2006 a total of 825 of 1370 randomized patients of the HD10 trial (60%) and 954 of 1422 patients of the HD11 trial (67%) were evaluated by the panel. Radiotherapy was rated as suboptimal in 47% of all reviewed cases. Although the participating RT centers received a precise RT prescription, most difficulties occurred in the adequate coverage of the IF (40%), followed by technical faults (12%). Deviations from the prescribed single daily dose (1.8-2 Gy), weekly dose, and total reference dose were rare (1%). Conclusions: As a consequence of these findings, radiation oncologists were trained on the definition of IF-RT at GHSG meetings and at the annual meetings of the German Society for Therapeutic Radiation Oncology. Possible correlations between RT quality and relapse rate will be investigated.« less

The role of Imaging and Radiation Oncology Core for precision medicine era of clinical trial

PubMed Central

Rosen, Mark

2017-01-01

Imaging and Radiation Oncology Core (IROC) services have been established for the quality assurance (QA) of imaging and radiotherapy (RT) for NCI’s Clinical Trial Network (NCTN) for any trials that contain imaging or RT. The randomized clinical trial is the gold standard for evidence-based medicine. QA ensures data quality, preventing noise from inferior treatments obscuring clinical trial outcome. QA is also found to be cost-effective. IROC has made great progress in multi-institution standardization and is expected to lead QA standardization, QA science in imaging and RT and to advance quality data analysis with big data in the future. The QA in the era of precision medicine is of paramount importance, when individualized decision making may depend on the quality and accuracy of RT and imaging. PMID:29218265

Bolus-dependent dosimetric effect of positioning errors for tangential scalp radiotherapy with helical tomotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lobb, Eric, E-mail: eclobb2@gmail.com

2014-04-01

The dosimetric effect of errors in patient position is studied on-phantom as a function of simulated bolus thickness to assess the need for bolus utilization in scalp radiotherapy with tomotherapy. A treatment plan is generated on a cylindrical phantom, mimicking a radiotherapy technique for the scalp utilizing primarily tangential beamlets. A planning target volume with embedded scalplike clinical target volumes (CTVs) is planned to a uniform dose of 200 cGy. Translational errors in phantom position are introduced in 1-mm increments and dose is recomputed from the original sinogram. For each error the maximum dose, minimum dose, clinical target dose homogeneitymore » index (HI), and dose-volume histogram (DVH) are presented for simulated bolus thicknesses from 0 to 10 mm. Baseline HI values for all bolus thicknesses were in the 5.5 to 7.0 range, increasing to a maximum of 18.0 to 30.5 for the largest positioning errors when 0 to 2 mm of bolus is used. Utilizing 5 mm of bolus resulted in a maximum HI value of 9.5 for the largest positioning errors. Using 0 to 2 mm of bolus resulted in minimum and maximum dose values of 85% to 94% and 118% to 125% of the prescription dose, respectively. When using 5 mm of bolus these values were 98.5% and 109.5%. DVHs showed minimal changes in CTV dose coverage when using 5 mm of bolus, even for the largest positioning errors. CTV dose homogeneity becomes increasingly sensitive to errors in patient position as bolus thickness decreases when treating the scalp with primarily tangential beamlets. Performing a radial expansion of the scalp CTV into 5 mm of bolus material minimizes dosimetric sensitivity to errors in patient position as large as 5 mm and is therefore recommended.« less

SU-F-P-18: Development of the Technical Training System for Patient Set-Up Considering Rotational Correction in the Virtual Environment Using Three-Dimensional Computer Graphic Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imura, K; Fujibuchi, T; Hirata, H

Purpose: Patient set-up skills in radiotherapy treatment room have a great influence on treatment effect for image guided radiotherapy. In this study, we have developed the training system for improving practical set-up skills considering rotational correction in the virtual environment away from the pressure of actual treatment room by using three-dimensional computer graphic (3DCG) engine. Methods: The treatment room for external beam radiotherapy was reproduced in the virtual environment by using 3DCG engine (Unity). The viewpoints to perform patient set-up in the virtual treatment room were arranged in both sides of the virtual operable treatment couch to assume actual performancemore » by two clinical staffs. The position errors to mechanical isocenter considering alignment between skin marker and laser on the virtual patient model were displayed by utilizing numerical values expressed in SI units and the directions of arrow marks. The rotational errors calculated with a point on the virtual body axis as the center of each rotation axis for the virtual environment were corrected by adjusting rotational position of the body phantom wound the belt with gyroscope preparing on table in a real space. These rotational errors were evaluated by describing vector outer product operations and trigonometric functions in the script for patient set-up technique. Results: The viewpoints in the virtual environment allowed individual user to visually recognize the position discrepancy to mechanical isocenter until eliminating the positional errors of several millimeters. The rotational errors between the two points calculated with the center point could be efficiently corrected to display the minimum technique mathematically by utilizing the script. Conclusion: By utilizing the script to correct the rotational errors as well as accurate positional recognition for patient set-up technique, the training system developed for improving patient set-up skills enabled individual user to indicate efficient positional correction methods easily.« less

Radiotherapy setup displacements in breast cancer patients: 3D surface imaging experience.

PubMed

Cravo Sá, Ana; Fermento, Ana; Neves, Dalila; Ferreira, Sara; Silva, Teresa; Marques Coelho, Carina; Vaandering, Aude; Roma, Ana; Quaresma, Sérgio; Bonnarens, Emmanuel

2018-01-01

In this study, we intend to compare two different setup procedures for female breast cancer patients. Imaging in radiotherapy provides a precise localization of the tumour, increasing the accuracy of the treatment delivery in breast cancer. Twenty breast cancer patients who underwent whole breast radiotherapy (WBRT) were selected for this study. Patients were divided into two groups of ten. Group one (G1) was positioned by tattoos and then the patient positioning was adjusted with the aid of AlignRT (Vision RT, London, UK). In group two (G2), patients were positioned only by tattoos. For both groups, the first 15 fractions were analyzed, a daily kilovoltage (kV) cone beam computed tomography (CBCT) image was made and then the rotational and translational displacements and, posteriorly, the systematic ( Σ ) and random ( σ ) errors were analyzed. The comparison of CBCT displacements for the two groups showed a statistically significant difference in the translational left-right (LR) direction ( ρ  = 0.03), considering that the procedure with AlignRT system has smaller lateral displacements. The results of systematic ( Σ ) and random ( σ ) errors showed that for translational displacements the group positioned only by tattoos (G2) demonstrated higher values of errors when compared with the group positioned with the aid of AlignRT (G1). AlignRT could help the positioning of breast cancer patients; however, it should be used with another imaging method.

Dose-Escalated Robotic SBRT for Stage I–II Prostate Cancer

PubMed Central

Meier, Robert

2015-01-01

Stereotactic body radiotherapy (SBRT) is the precise external delivery of very high-dose radiotherapy to targets in the body, with treatment completed in one to five fractions. SBRT should be an ideal approach for organ-confined prostate cancer because (I) dose-escalation should yield improved rates of cancer control; (II) the unique radiobiology of prostate cancer favors hypofractionation; and (III) the conformal nature of SBRT minimizes high-dose radiation delivery to immediately adjacent organs, potentially reducing complications. This approach is also more convenient for patients, and is cheaper than intensity-modulated radiotherapy (IMRT). Several external beam platforms are capable of delivering SBRT for early-stage prostate cancer, although most of the mature reported series have employed a robotic non-coplanar platform (i.e., CyberKnife). Several large studies report 5-year biochemical relapse rates which compare favorably to IMRT. Rates of late GU toxicity are similar to those seen with IMRT, and rates of late rectal toxicity may be less than with IMRT and low-dose rate brachytherapy. Patient-reported quality of life (QOL) outcomes appear similar to IMRT in the urinary domain. Bowel QOL may be less adversely affected by SBRT than with other radiation modalities. After 5 years of follow-up, SBRT delivered on a robotic platform is yielding outcomes at least as favorable as IMRT, and may be considered appropriate therapy for stage I–II prostate cancer. PMID:25905037

Standard and Nonstandard Craniospinal Radiotherapy Using Helical TomoTherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parker, William, E-mail: william@medphys.mcgill.c; Brodeur, Marylene; Roberge, David

2010-07-01

Purpose: To show the advantages of planning and delivering craniospinal radiotherapy with helical TomoTherapy (TomoTherapy Inc., Madison, WI) by presenting 4 cases treated at our institution. Methods and Materials: We first present a standard case of craniospinal irradiation in a patient with recurrent myxopapillary ependymoma (MPE) and follow this with 2 cases requiring differential dosing to multiple target volumes. One of these, a patient with recurrent medulloblastoma, required a lower dose to be delivered to the posterior fossa because the patient had been previously irradiated to the full dose, and the other required concurrent boosts to leptomeningeal metastases as partmore » of his treatment for newly diagnosed MPE. The final case presented is a patient with pronounced scoliosis who required spinal irradiation for recurrent MPE. Results: The four cases presented were planned and treated successfully with Helical Tomotherapy. Conclusions: Helical TomoTherapy delivers continuous arc-based intensity-modulated radiotherapy that gives high conformality and excellent dose homogeneity for the target volumes. Increased healthy tissue sparing is achieved at higher doses albeit at the expense of larger volumes of tissue receiving lower doses. Helical TomoTherapy allows for differential dosing of multiple targets, resulting in very elegant dose distributions. Daily megavoltage computed tomography imaging allows for precision of patient positioning, permitting a reduction in planning margins and increased healthy tissue sparing in comparison with standard techniques.« less

Long-term outcomes of late course accelerated hyper-fractionated radiotherapy for localized esophageal carcinoma in Mainland China: a meta-analysis.

PubMed

Zhang, Y W; Chen, L; Bai, Y; Zheng, X

2011-09-01

Published data on the long-term survival results of patients with localized esophageal carcinoma receiving late course accelerated hyper-fractionated radiotherapy (LCAF RT) versus conventional fractionated radiotherapy (CF RT) are inconclusive. In order to derive a more precise estimation of the both treatment-regimes, a meta-analysis based on systematic review of published articles was performed. A meta-analysis was performed using trials identified through Pubmed and Chinese national knowledge infrastructure. Results in 5-year survival and 5-year local control were collected from randomized trials comparing LCAF RT with CF RT. Review Manager (The Cochrane Collaboration, Oxford, England) and Stata software (Stata Corporation, College Station, TX, USA) were used for data management. A total of 11 trials were involved in this analysis with 572 cases and 567 controls. Our results showed that LCAF RT, compared with CF RT, significantly improved the 5-year survival (odds ratio [OR]= 2.93, 95% confidence interval [CI]: 2.15-4.00, P < 0.00001) and 5-year local control (OR = 3.96, 95% CI: 2.91-5.38, P < 0.00001). LCAF RT was more therapeutically beneficial than CF RT in the localized esophageal carcinoma. © 2011 Copyright the Authors. Journal compilation © 2011, Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

Sample Size and Item Parameter Estimation Precision When Utilizing the One-Parameter "Rasch" Model

ERIC Educational Resources Information Center

Custer, Michael

2015-01-01

This study examines the relationship between sample size and item parameter estimation precision when utilizing the one-parameter model. Item parameter estimates are examined relative to "true" values by evaluating the decline in root mean squared deviation (RMSD) and the number of outliers as sample size increases. This occurs across…

TU-H-CAMPUS-JeP2-01: Inter-Observer Delineation Comparison of Visible Glandular Breast Tissue On Magnetic Resonance Imaging and Computed Tomography (prone and Supine)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pogson, EM; University of Wollongong, Wollongong, NSW; Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW

2016-06-15

Purpose: Breast cancers predominantly arise from Glandular Breast Tissue (GBT). If the GBT can be treated effectively post-operatively utilising radiotherapy this may be adequate volumetric coverage for adjuvant breast radiotherapy. Adequate imaging of the GBT is necessary and will be assessed between MRI and CT modalities. GBT visualisation is acknowledged to be qualitatively superior on Magnetic Resonance Image (MRI) compared to Computed Tomography (CT), the current radiotherapy imaging standard, however this has not been quantitatively assessed. For radiotherapy purposes it is important that any treatment volume can be consistently defined between observers. This study investigates the consistency of CT andmore » MRI GBT contours for potential radiotherapy planning. Methods: Ten experts (9 breast radiation oncologists and 1 radiologist) contoured the extent of the visible GBT for 33 patients on MRI and CT (both without contrast), which was performed according to a contouring guideline in supine and prone patient positions. The GBT volume was not a conventional whole breast radiotherapy planning volume, but rather the extent of GBT that was indicated from the CT or MR imaging. Volumes were compared utilizing the dice similarity coefficient (DSC), kappa statistic, and Hausdorff Distances (HDs) to ascertain the modality that was most consistently volumed. Results: The inter-observer concordance was of substantial agreement (kappa above 0.6) for the CT supine, CT prone, MRI supine and MRI prone datasets. The MRI GBT volumes were larger than the CT GBT volumes (p<0.001). Inter-observer conformity was higher for CT than MRI, although the magnitude of this difference was small (VOI<0.04). Conformity between modalities (CT and MRI) was in agreement for both prone and supine, DSC=0.75. Prone GBT volumes were larger than supine for both MRI and CT. Conclusion: MRI improves the extent of GBT delineation. The role of MRI guided, GBT-targeted radiotherapy requires investigation in a clinical trial. This work was supported by a grant number APP1033237 from Cancer Australia and the National Breast Cancer Foundation.« less

Radiogenetic therapy: strategies to overcome tumor resistance.

PubMed

Marples, B; Greco, O; Joiner, M C; Scott, S D

2003-01-01

The aim of cancer gene therapy is to selectively kill malignant cells at the tumor site, by exploiting traits specific to cancer cells and/or solid tumors. Strategies that take advantage of biological features common to different tumor types are particularly promising, since they have wide clinical applicability. Much attention has focused on genetic methods that complement radiotherapy, the principal treatment modality, or that exploit hypoxia, the most ubiquitous characteristic of most solid cancers. The goal of this review is to highlight two promising gene therapy methods developed specifically to target the tumor volume that can be readily used in combination with radiotherapy. The first approach uses radiation-responsive gene promoters to control the selective expression of a suicide gene (e.g., herpes simplex virus thymidine kinase) to irradiated tissue only, leading to targeted cell killing in the presence of a prodrug (e.g., ganciclovir). The second method utilizes oxygen-dependent promoters to produce selective therapeutic gene expression and prodrug activation in hypoxic cells, which are refractive to conventional radiotherapy. Further refining of tumor targeting can be achieved by combining radiation and hypoxia responsive elements in chimeric promoters activated by either and dual stimuli. The in vitro and in vivo studies described in this review suggest that the combination of gene therapy and radiotherapy protocols has potential for use in cancer care, particularly in cases currently refractory to treatment as a result of inherent or hypoxia-mediated radioresistance.

[Radiation therapy for cancer--challenges and opportunities].

PubMed

Specht, Lena

2010-02-01

Radiotherapy for cancer previously employed large treatment fields whereby cures were obtained. However, long-term follow-up documented serious long-term complications due to irradiation of normal tissues. Modern technology makes it possible to very accurately shape the high-dose volume. However, new problems emerge. Organ movement must be managed and the precise definition of the extent of the tumour tissue is crucial. Positron emission tomography and magnetic resonance imaging are increasingly used. Biological imaging may enable us to image tumour biology more accurately and modify radiation doses accordingly.

MR-CBCT image-guided system for radiotherapy of orthotopic rat prostate tumors.

PubMed

Chiu, Tsuicheng D; Arai, Tatsuya J; Campbell Iii, James; Jiang, Steve B; Mason, Ralph P; Stojadinovic, Strahinja

2018-01-01

Multi-modality image-guided radiotherapy is the standard of care in contemporary cancer management; however, it is not common in preclinical settings due to both hardware and software limitations. Soft tissue lesions, such as orthotopic prostate tumors, are difficult to identify using cone beam computed tomography (CBCT) imaging alone. In this study, we characterized a research magnetic resonance (MR) scanner for preclinical studies and created a protocol for combined MR-CBCT image-guided small animal radiotherapy. Two in-house dual-modality, MR and CBCT compatible, phantoms were designed and manufactured using 3D printing technology. The phantoms were used for quality assurance tests and to facilitate end-to-end testing for combined preclinical MR and CBCT based treatment planning. MR and CBCT images of the phantoms were acquired utilizing a Varian 4.7 T scanner and XRad-225Cx irradiator, respectively. The geometry distortion was assessed by comparing MR images to phantom blueprints and CBCT. The corrected MR scans were co-registered with CBCT and subsequently used for treatment planning. The fidelity of 3D printed phantoms compared to the blueprint design yielded favorable agreement as verified with the CBCT measurements. The geometric distortion, which varied between -5% and 11% throughout the scanning volume, was substantially reduced to within 0.4% after correction. The distortion free MR images were co-registered with the corresponding CBCT images and imported into a commercial treatment planning software SmART Plan. The planning target volume (PTV) was on average 19% smaller when contoured on the corrected MR-CBCT images relative to raw images without distortion correction. An MR-CBCT based preclinical workflow was successfully designed and implemented for small animal radiotherapy. Combined MR-CBCT image-guided radiotherapy for preclinical research potentially delivers enhanced relevance to human radiotherapy for various disease sites. This novel protocol is wide-ranging and not limited to the orthotopic prostate tumor study presented in the study.

Precision Health Economics and Outcomes Research to Support Precision Medicine: Big Data Meets Patient Heterogeneity on the Road to Value.

PubMed

Chen, Yixi; Guzauskas, Gregory F; Gu, Chengming; Wang, Bruce C M; Furnback, Wesley E; Xie, Guotong; Dong, Peng; Garrison, Louis P

2016-11-02

The "big data" era represents an exciting opportunity to utilize powerful new sources of information to reduce clinical and health economic uncertainty on an individual patient level. In turn, health economic outcomes research (HEOR) practices will need to evolve to accommodate individual patient-level HEOR analyses. We propose the concept of "precision HEOR", which utilizes a combination of costs and outcomes derived from big data to inform healthcare decision-making that is tailored to highly specific patient clusters or individuals. To explore this concept, we discuss the current and future roles of HEOR in health sector decision-making, big data and predictive analytics, and several key HEOR contexts in which big data and predictive analytics might transform traditional HEOR into precision HEOR. The guidance document addresses issues related to the transition from traditional to precision HEOR practices, the evaluation of patient similarity analysis and its appropriateness for precision HEOR analysis, and future challenges to precision HEOR adoption. Precision HEOR should make precision medicine more realizable by aiding and adapting healthcare resource allocation. The combined hopes for precision medicine and precision HEOR are that individual patients receive the best possible medical care while overall healthcare costs remain manageable or become more cost-efficient.

Precision Health Economics and Outcomes Research to Support Precision Medicine: Big Data Meets Patient Heterogeneity on the Road to Value

PubMed Central

Chen, Yixi; Guzauskas, Gregory F.; Gu, Chengming; Wang, Bruce C. M.; Furnback, Wesley E.; Xie, Guotong; Dong, Peng; Garrison, Louis P.

2016-01-01

The “big data” era represents an exciting opportunity to utilize powerful new sources of information to reduce clinical and health economic uncertainty on an individual patient level. In turn, health economic outcomes research (HEOR) practices will need to evolve to accommodate individual patient–level HEOR analyses. We propose the concept of “precision HEOR”, which utilizes a combination of costs and outcomes derived from big data to inform healthcare decision-making that is tailored to highly specific patient clusters or individuals. To explore this concept, we discuss the current and future roles of HEOR in health sector decision-making, big data and predictive analytics, and several key HEOR contexts in which big data and predictive analytics might transform traditional HEOR into precision HEOR. The guidance document addresses issues related to the transition from traditional to precision HEOR practices, the evaluation of patient similarity analysis and its appropriateness for precision HEOR analysis, and future challenges to precision HEOR adoption. Precision HEOR should make precision medicine more realizable by aiding and adapting healthcare resource allocation. The combined hopes for precision medicine and precision HEOR are that individual patients receive the best possible medical care while overall healthcare costs remain manageable or become more cost-efficient. PMID:27827859

On the use of particle filters for electromagnetic tracking in high dose rate brachytherapy.

PubMed

Götz, Th I; Lahmer, G; Brandt, T; Kallis, K; Strnad, V; Bert, Ch; Hensel, B; Tomé, A M; Lang, E W

2017-09-12

Modern radiotherapy of female breast cancers often employs high dose rate brachytherapy, where a radioactive source is moved inside catheters, implanted in the female breast, according to a prescribed treatment plan. Source localization relative to the patient's anatomy is determined with solenoid sensors whose spatial positions are measured with an electromagnetic tracking system. Precise sensor dwell position determination is of utmost importance to assure irradiation of the cancerous tissue according to the treatment plan. We present a hybrid data analysis system which combines multi-dimensional scaling with particle filters to precisely determine sensor dwell positions in the catheters during subsequent radiation treatment sessions. Both techniques are complemented with empirical mode decomposition for the removal of superimposed breathing artifacts. We show that the hybrid model robustly and reliably determines the spatial positions of all catheters used during the treatment and precisely determines any deviations of actual sensor dwell positions from the treatment plan. The hybrid system only relies on sensor positions measured with an EMT system and relates them to the spatial positions of the implanted catheters as initially determined with a computed x-ray tomography.

On-Line Use of Three-Dimensional Marker Trajectory Estimation From Cone-Beam Computed Tomography Projections for Precise Setup in Radiotherapy for Targets With Respiratory Motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Worm, Esben S., E-mail: esbeworm@rm.dk; Department of Medical Physics, Aarhus University Hospital, Aarhus; Hoyer, Morten

2012-05-01

Purpose: To develop and evaluate accurate and objective on-line patient setup based on a novel semiautomatic technique in which three-dimensional marker trajectories were estimated from two-dimensional cone-beam computed tomography (CBCT) projections. Methods and Materials: Seven treatment courses of stereotactic body radiotherapy for liver tumors were delivered in 21 fractions in total to 6 patients by a linear accelerator. Each patient had two to three gold markers implanted close to the tumors. Before treatment, a CBCT scan with approximately 675 two-dimensional projections was acquired during a full gantry rotation. The marker positions were segmented in each projection. From this, the three-dimensionalmore » marker trajectories were estimated using a probability based method. The required couch shifts for patient setup were calculated from the mean marker positions along the trajectories. A motion phantom moving with known tumor trajectories was used to examine the accuracy of the method. Trajectory-based setup was retrospectively used off-line for the first five treatment courses (15 fractions) and on-line for the last two treatment courses (6 fractions). Automatic marker segmentation was compared with manual segmentation. The trajectory-based setup was compared with setup based on conventional CBCT guidance on the markers (first 15 fractions). Results: Phantom measurements showed that trajectory-based estimation of the mean marker position was accurate within 0.3 mm. The on-line trajectory-based patient setup was performed within approximately 5 minutes. The automatic marker segmentation agreed with manual segmentation within 0.36 {+-} 0.50 pixels (mean {+-} SD; pixel size, 0.26 mm in isocenter). The accuracy of conventional volumetric CBCT guidance was compromised by motion smearing ({<=}21 mm) that induced an absolute three-dimensional setup error of 1.6 {+-} 0.9 mm (maximum, 3.2) relative to trajectory-based setup. Conclusions: The first on-line clinical use of trajectory estimation from CBCT projections for precise setup in stereotactic body radiotherapy was demonstrated. Uncertainty in the conventional CBCT-based setup procedure was eliminated with the new method.« less

NOTE: Fluoroscopic gating without implanted fiducial markers for lung cancer radiotherapy based on support vector machines

NASA Astrophysics Data System (ADS)

Cui, Ying; Dy, Jennifer G.; Alexander, Brian; Jiang, Steve B.

2008-08-01

Various problems with the current state-of-the-art techniques for gated radiotherapy have prevented this new treatment modality from being widely implemented in clinical routine. These problems are caused mainly by applying various external respiratory surrogates. There might be large uncertainties in deriving the tumor position from external respiratory surrogates. While tracking implanted fiducial markers has sufficient accuracy, this procedure may not be widely accepted due to the risk of pneumothorax. Previously, we have developed a technique to generate gating signals from fluoroscopic images without implanted fiducial markers using template matching methods (Berbeco et al 2005 Phys. Med. Biol. 50 4481-90, Cui et al 2007b Phys. Med. Biol. 52 741-55). In this note, our main contribution is to provide a totally different new view of the gating problem by recasting it as a classification problem. Then, we solve this classification problem by a well-studied powerful classification method called a support vector machine (SVM). Note that the goal of an automated gating tool is to decide when to turn the beam ON or OFF. We treat ON and OFF as the two classes in our classification problem. We create our labeled training data during the patient setup session by utilizing the reference gating signal, manually determined by a radiation oncologist. We then pre-process these labeled training images and build our SVM prediction model. During treatment delivery, fluoroscopic images are continuously acquired, pre-processed and sent as an input to the SVM. Finally, our SVM model will output the predicted labels as gating signals. We test the proposed technique on five sequences of fluoroscopic images from five lung cancer patients against the reference gating signal as ground truth. We compare the performance of the SVM to our previous template matching method (Cui et al 2007b Phys. Med. Biol. 52 741-55). We find that the SVM is slightly more accurate on average (1-3%) than the template matching method, when delivering the target dose. And the average duty cycle is 4-6% longer. Given the very limited patient dataset, we cannot conclude that the SVM is more accurate and efficient than the template matching method. However, our preliminary results show that the SVM is a potentially precise and efficient algorithm for generating gating signals for radiotherapy. This work demonstrates that the gating problem can be considered as a classification problem and solved accordingly.

Treatment and survival of second primary early-stage lung cancer, following treatment of head and neck cancer in the Netherlands.

PubMed

Louie, Alexander V; Damhuis, Ronald A; Haasbeek, Cornelis J; Warner, Andrew; Rodin, Danielle; Slotman, Ben J; Leemans, C Rene; Senan, Suresh

2016-04-01

The goal of this study was to evaluate treatment patterns and outcomes in early stage (ES) second primary lung cancer (SPLC) after head and neck squamous cell cancer (HNSCC), in the Netherlands. Details of patients diagnosed between 1997 and 2011 with either an ES primary, or a SPLC after HNSCC, were obtained from the Netherlands Cancer Registry. Survival outcomes were compared between treatment groups before, and after, 2005. Univariable and multivariable Cox regression modeling were performed to determine factors prognostic for OS in ES-SPLC. In total, 21,648 patients were diagnosed with ES primary (n=21,032) or SPLC (n=616). Use of surgery for ES-SPLC decreased significantly over time (range 71-44%, p<0.001), while the proportion of such patients receiving radiotherapy increased (range 17-41%, p<0.001). Prior to 2005, OS after surgery in ES-SPLC was significantly better than when compared to radiation, but no difference in OS was noted between surgery and radiotherapy after 2005 (p=0.116). There were no significant differences in OS between treatment eras for surgery (p=0.751) and with palliative care (p=0.306), but a significant improvement in OS was noted for radiotherapy (p=0.049). Multivariable modeling revealed that age, T-stage, HNSCC location and treatment type were associated with worse OS in the later era. Changes in the treatment patterns in HNSCC survivors presenting with ES-SPLC were observed in the Netherlands, with less surgery and increased utilization of radiotherapy. No differences in OS were observed between patients undergoing either surgery or radiotherapy after 2005, suggesting that both local modalities were equally effective. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Comparison of Toxicity Between Intensity-Modulated Radiotherapy and 3-Dimensional Conformal Radiotherapy for Locally Advanced Non-small-cell Lung Cancer.

PubMed

Ling, Diane C; Hess, Clayton B; Chen, Allen M; Daly, Megan E

2016-01-01

The role of intensity-modulated radiotherapy (IMRT) in reducing treatment-related toxicity for locally advanced non-small-cell lung cancer (NSCLC) remains incompletely defined. We compared acute toxicity and oncologic outcomes in a large cohort of patients treated with IMRT or 3-dimensional conformal radiotherapy (3-DCRT), with or without elective nodal irradiation (ENI). A single-institution retrospective review was performed evaluating 145 consecutive patients with histologically confirmed stage III NSCLC treated with definitive chemoradiotherapy. Sixty-five (44.8%) were treated with 3-DCRT using ENI, 43 (30.0%) with 3-DCRT using involved-field radiotherapy (IFRT), and 37 (25.5%) with IMRT using IFRT. All patients received concurrent chemotherapy. Comparison of acute toxicities by treatment technique (IMRT vs. 3-DCRT) and extent of nodal irradiation (3-DCRT-IFRT vs. 3-DCRT-ENI) was performed for grade 2 or higher esophagitis or pneumonitis, number of acute hospitalizations, incidence of opioid requirement, percutaneous endoscopic gastrostomy utilization, and percentage weight loss during treatment. Local control and overall survival were analyzed by the Kaplan-Meier method. We identified no significant differences in any measures of acute toxicity by treatment technique or extent of nodal irradiation. There was a trend toward lower rates of grade 2 or higher pneumonitis among IMRT patients compared to 3-DCRT patients (5.4% vs. 23.0%; P = .065). Local control and overall survival were similar between cohorts. Acute and subacute toxicities were similar for patients treated with IMRT and with 3-DCRT with or without ENI, with a nonsignificant trend toward a reduction in pneumonitis with IMRT. Larger studies are needed to better define which patients will benefit from IMRT. Copyright © 2016 Elsevier Inc. All rights reserved.

Development of a novel remote patient monitoring system: the advanced symptom management system for radiotherapy to improve the symptom experience of patients with lung cancer receiving radiotherapy.

PubMed

Maguire, Roma; Ream, Emma; Richardson, Alison; Connaghan, John; Johnston, Bridget; Kotronoulas, Grigorios; Pedersen, Vibe; McPhelim, John; Pattison, Natalie; Smith, Allison; Webster, Lorraine; Taylor, Anne; Kearney, Nora

2015-01-01

The use of technology-enhanced patient-reported outcome measures to monitor the symptoms experienced by people with cancer is an effective way to offer timely care. This study aimed to (a) explore the feasibility and acceptability of the Advanced Symptom Management System with patients with lung cancer receiving radiotherapy and clinicians involved in their care and (b) assess changes in patient outcomes during implementation of the Advanced Symptom Management System with patients with lung cancer receiving radiotherapy in clinical practice. A repeated-measures, single-arm, mixed-methods study design was used involving poststudy interviews and completion of patient-reported outcome measures at baseline and end of treatment with 16 patients with lung cancer and 13 clinicians who used this mobile phone-based symptom monitoring system. Only rarely did patients report problems in using the handset and they felt that the system covered all relevant symptoms and helped them to manage their symptoms and effectively communicate with clinicians. Clinical improvements in patient anxiety, drowsiness, and self-care self-efficacy were also observed. Clinicians perceived the use of "real-time" risk algorithms and automated self-care advice provided to patients as positively contributing to clinical care. Reducing the complexity of the system was seen as important to promote its utility. Although preliminary, these results suggest that monitoring patient symptoms using mobile technology in the context of radiotherapy for lung cancer is feasible and acceptable in clinical practice. Future research would be most beneficial if the use of this technology was focused on the postradiotherapy phase and expanded the scope of the system to encompass a wider range of supportive care needs.

Optical computed tomography in PRESAGE® three-dimensional dosimetry: Challenges and prospective.

PubMed

Khezerloo, Davood; Nedaie, Hassan Ali; Farhood, Bagher; Zirak, Alireza; Takavar, Abbas; Banaee, Nooshin; Ahmadalidokht, Isa; Kron, Tomas

2017-01-01

With the advent of new complex but precise radiotherapy techniques, the demands for an accurate, feasible three-dimensional (3D) dosimetry system have been increased. A 3D dosimeter system generally should not only have accurate and precise results but should also feasible, inexpensive, and time consuming. Recently, one of the new candidates for 3D dosimetry is optical computed tomography (CT) with a radiochromic dosimeter such as PRESAGE®. Several generations of optical CT have been developed since the 90s. At the same time, a large attempt has been also done to introduce the robust dosimeters that compatible with optical CT scanners. In 2004, PRESAGE® dosimeter as a new radiochromic solid plastic dosimeters was introduced. In this decade, a large number of efforts have been carried out to enhance optical scanning methods. This article attempts to review and reflect on the results of these investigations.

Characterization of a synthetic single crystal diamond detector for dosimetry in spatially fractionated synchrotron x-ray fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Livingstone, Jayde, E-mail: Jayde.Livingstone@sync

Purpose: Modern radiotherapy modalities often use small or nonstandard fields to ensure highly localized and precise dose delivery, challenging conventional clinical dosimetry protocols. The emergence of preclinical spatially fractionated synchrotron radiotherapies with high dose-rate, sub-millimetric parallel kilovoltage x-ray beams, has pushed clinical dosimetry to its limit. A commercially available synthetic single crystal diamond detector designed for small field dosimetry has been characterized to assess its potential as a dosimeter for synchrotron microbeam and minibeam radiotherapy. Methods: Experiments were carried out using a synthetic diamond detector on the imaging and medical beamline (IMBL) at the Australian Synchrotron. The energy dependence ofmore » the detector was characterized by cross-referencing with a calibrated ionization chamber in monoenergetic beams in the energy range 30–120 keV. The dose-rate dependence was measured in the range 1–700 Gy/s. Dosimetric quantities were measured in filtered white beams, with a weighted mean energy of 95 keV, in broadbeam and spatially fractionated geometries, and compared to reference dosimeters. Results: The detector exhibits an energy dependence; however, beam quality correction factors (k{sub Q}) have been measured for energies in the range 30–120 keV. The k{sub Q} factor for the weighted mean energy of the IMBL radiotherapy spectrum, 95 keV, is 1.05 ± 0.09. The detector response is independent of dose-rate in the range 1–700 Gy/s. The percentage depth dose curves measured by the diamond detector were compared to ionization chambers and agreed to within 2%. Profile measurements of microbeam and minibeam arrays were performed. The beams are well resolved and the full width at halfmaximum agrees with the nominal width of the beams. The peak to valley dose ratio (PVDR) calculated from the profiles at various depths in water agrees within experimental error with PVDR calculations from Gafchromic film data. Conclusions: The synthetic diamond detector is now well characterized and will be used to develop an experimental dosimetry protocol for spatially fractionated synchrotron radiotherapy.« less

Dosimetric Comparison in Breast Radiotherapy of 4 MV and 6 MV on Physical Chest Simulator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donato da Silva, Sabrina; Passos Ribeiro Campos, Tarcisio; Batista Nogueira, Luciana

2015-07-01

According to the World Health Organization (2014) breast cancer is the main cause of death by cancer in women worldwide. The biggest challenge of radiotherapy in the treatment of cancer is to deposit the entire prescribed dose homogeneously in the breast, sparing the surrounding tissue. In this context, this paper aimed at evaluating and comparing internal dose distribution in the mammary gland based on experimental procedures submitted to two distinct energy spectra produced in breast cancer radiotherapy. The methodology consisted of reproducing opposite parallel fields used in the treatment of breast tumors in a chest phantom. This simulator with syntheticmore » breast, composed of equivalent tissue material (TE), was previously developed by the NRI Research Group (UFMG). The computer tomography (CT) scan of the simulator was obtained antecedently. The radiotherapy planning systems (TPS) in the chest phantom were performed in the ECLIPSE system from Varian Medical Systems and CAT 3D system from MEVIS. The irradiations were reproduced in the Varian linear accelerator, model SL- 20 Precise, 6 MV energy and Varian linear accelerator, 4 MV Clinac 6x SN11 model. Calibrations of the absorbed dose versus optical density from radiochromic films were generated in order to obtain experimental dosimetric distribution at the films positioned within the glandular and skin equivalent tissues of the chest phantom. The spatial dose distribution showed equivalence with the TPS on measurement data performed in the 6 MV spectrum. The average dose found in radiochromic films placed on the skin ranged from 49 to 79%, and from 39 to 49% in the mammary areola, for the prescribed dose. Dosimetric comparisons between the spectra of 4 and 6 MV, keeping the constant geometry of the fields applied in the same phantom, will be presented showing their equivalence in breast radiotherapy, as well as the variations will be discussed. To sum up, the dose distribution has reached the value expected in the breast dose of the 180 cGy in a wide range of the film in the glandular TE in both spectra. (authors)« less

Agreement between gamma passing rates using computed tomography in radiotherapy and secondary cancer risk prediction from more advanced dose calculated models

PubMed Central

Balosso, Jacques

2017-01-01

Background During the past decades, in radiotherapy, the dose distributions were calculated using density correction methods with pencil beam as type ‘a’ algorithm. The objectives of this study are to assess and evaluate the impact of dose distribution shift on the predicted secondary cancer risk (SCR), using modern advanced dose calculation algorithms, point kernel, as type ‘b’, which consider change in lateral electrons transport. Methods Clinical examples of pediatric cranio-spinal irradiation patients were evaluated. For each case, two radiotherapy treatment plans with were generated using the same prescribed dose to the target resulting in different number of monitor units (MUs) per field. The dose distributions were calculated, respectively, using both algorithms types. A gamma index (γ) analysis was used to compare dose distribution in the lung. The organ equivalent dose (OED) has been calculated with three different models, the linear, the linear-exponential and the plateau dose response curves. The excess absolute risk ratio (EAR) was also evaluated as (EAR = OED type ‘b’ / OED type ‘a’). Results The γ analysis results indicated an acceptable dose distribution agreement of 95% with 3%/3 mm. Although, the γ-maps displayed dose displacement >1 mm around the healthy lungs. Compared to type ‘a’, the OED values from type ‘b’ dose distributions’ were about 8% to 16% higher, leading to an EAR ratio >1, ranged from 1.08 to 1.13 depending on SCR models. Conclusions The shift of dose calculation in radiotherapy, according to the algorithm, can significantly influence the SCR prediction and the plan optimization, since OEDs are calculated from DVH for a specific treatment. The agreement between dose distribution and SCR prediction depends on dose response models and epidemiological data. In addition, the γ passing rates of 3%/3 mm does not translate the difference, up to 15%, in the predictions of SCR resulting from alternative algorithms. Considering that modern algorithms are more accurate, showing more precisely the dose distributions, but that the prediction of absolute SCR is still very imprecise, only the EAR ratio could be used to rank radiotherapy plans. PMID:28811995

An efficient and robust MRI-guided radiotherapy planning approach for targeting abdominal organs and tumours in the mouse

PubMed Central

Bird, Luke; Tullis, Iain D. C.; Newman, Robert G.; Corroyer-Dulmont, Aurelien; Falzone, Nadia; Azad, Abul; Vallis, Katherine A.; Sansom, Owen J.; Muschel, Ruth J.; Vojnovic, Borivoj; Hill, Mark A.; Fokas, Emmanouil; Smart, Sean C.

2017-01-01

Introduction Preclinical CT-guided radiotherapy platforms are increasingly used but the CT images are characterized by poor soft tissue contrast. The aim of this study was to develop a robust and accurate method of MRI-guided radiotherapy (MR-IGRT) delivery to abdominal targets in the mouse. Methods A multimodality cradle was developed for providing subject immobilisation and its performance was evaluated. Whilst CT was still used for dose calculations, target identification was based on MRI. Each step of the radiotherapy planning procedure was validated initially in vitro using BANG gel dosimeters. Subsequently, MR-IGRT of normal adrenal glands with a size-matched collimated beam was performed. Additionally, the SK-N-SH neuroblastoma xenograft model and the transgenic KPC model of pancreatic ductal adenocarcinoma were used to demonstrate the applicability of our methods for the accurate delivery of radiation to CT-invisible abdominal tumours. Results The BANG gel phantoms demonstrated a targeting efficiency error of 0.56 ± 0.18 mm. The in vivo stability tests of body motion during MR-IGRT and the associated cradle transfer showed that the residual body movements are within this MR-IGRT targeting error. Accurate MR-IGRT of the normal adrenal glands with a size-matched collimated beam was confirmed by γH2AX staining. Regression in tumour volume was observed almost immediately post MR-IGRT in the neuroblastoma model, further demonstrating accuracy of x-ray delivery. Finally, MR-IGRT in the KPC model facilitated precise contouring and comparison of different treatment plans and radiotherapy dose distributions not only to the intra-abdominal tumour but also to the organs at risk. Conclusion This is, to our knowledge, the first study to demonstrate preclinical MR-IGRT in intra-abdominal organs. The proposed MR-IGRT method presents a state-of-the-art solution to enabling robust, accurate and efficient targeting of extracranial organs in the mouse and can operate with a sufficiently high throughput to allow fractionated treatments to be given. PMID:28453537

Preservation of future fertility in pediatric patients with cancer.

PubMed

de Lambert, G; Poirot, C; Guérin, F; Brugières, L; Martelli, H

2018-06-01

The cure rate for childhood and adolescent patients with cancer has currently reached almost 80% and protecting future fertility and thereby promoting quality of life have become a major challenge in the care of these patients (Bioethics Law, 2004). Age, sex and associated treatments influence the risk of future subfertility. Certain chemotherapies (particularly alkylating agents) and radiotherapy fields that include the gonads or hypothalamopituitary axis may negatively impact the future fertility of patients. Evaluation of the gonadotoxic potential of therapeutic measures and the utilization of appropriate methods to preserve fertility require the combined efforts of a multidisciplinary team that includes pediatric oncologists, radiotherapists, surgeons, reproductive physicians and biologists and psychologists. Techniques for fertility preservation vary depending on the age of the child and range from surgical transposition of the gonads for pelvic radiotherapy to cryopreservation of the ovary or testicle in case of sterilizing chemotherapy. While scientists still do not yet fully understand the maturation of immature germ cells, these children will be seeking the assistance of Medically Assisted Procreation (MAP) in 20-30 years. In the meanwhile, it is to be hoped that many more advances will be achieved in the utilization of harvested germinal tissue. Copyright © 2018. Published by Elsevier Masson SAS.

A review of ion sources for medical accelerators (invited)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muramatsu, M.; Kitagawa, A.

2012-02-15

There are two major medical applications of ion accelerators. One is a production of short-lived isotopes for radionuclide imaging with positron emission tomography and single photon emission computer tomography. Generally, a combination of a source for negative ions (usually H- and/or D-) and a cyclotron is used; this system is well established and distributed over the world. Other important medical application is charged-particle radiotherapy, where the accelerated ion beam itself is being used for patient treatment. Two distinctly different methods are being applied: either with protons or with heavy-ions (mostly carbon ions). Proton radiotherapy for deep-seated tumors has become widespreadmore » since the 1990s. The energy and intensity are typically over 200 MeV and several 10{sup 10} pps, respectively. Cyclotrons as well as synchrotrons are utilized. The ion source for the cyclotron is generally similar to the type for production of radioisotopes. For a synchrotron, one applies a positive ion source in combination with an injector linac. Carbon ion radiotherapy awakens a worldwide interest. About 6000 cancer patients have already been treated with carbon beams from the Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences in Japan. These clinical results have clearly verified the advantages of carbon ions. Heidelberg Ion Therapy Center and Gunma University Heavy Ion Medical Center have been successfully launched. Several new facilities are under commissioning or construction. The beam energy is adjusted to the depth of tumors. It is usually between 140 and 430 MeV/u. Although the beam intensity depends on the irradiation method, it is typically several 10{sup 8} or 10{sup 9} pps. Synchrotrons are only utilized for carbon ion radiotherapy. An ECR ion source supplies multi-charged carbon ions for this requirement. Some other medical applications with ion beams attract developer's interests. For example, the several types of accelerators are under development for the boron neutron capture therapy. This treatment is conventionally demonstrated by a nuclear reactor, but it is strongly expected to replace the reactor by the accelerator. We report status of ion source for medical application and such scope for further developments.« less

SU-E-J-223: A BOLD Contrast Imaging Sequence to Evaluate Oxygenation Changes Due to Breath Holding for Breast Radiotherapy: A Pilot Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamson, J; Chang, Z; Cai, J

Purpose: To develop a robust MRI sequence to measure BOLD breath hold induced contrast in context of breast radiotherapy. Methods: Two sequences were selected from prior studies as candidates to measure BOLD contrast attributable to breath holding within the breast: (1) T2* based Gradient Echo EPI (TR/TE = 500/41ms, flip angle = 60°), and (2) T2 based Single Shot Fast Spin Echo (SSFSE) (TR/TE = 3000/60ms). We enrolled ten women post-lumpectomy for breast cancer who were undergoing treatment planning for whole breast radiotherapy. Each session utilized a 1.5T GE MRI and 4 channel breast coil with the subject immobilized pronemore » on a custom board. For each sequence, 1–3 planes of the lumpectomy breast were imaged continuously during a background measurement (1min) and intermittent breath holds (20–40s per breath hold, 3–5 holds per sequence). BOLD contrast was quantified as correlation of changes in per-pixel intensity with the breath hold schedule convolved with a hemodynamic response function. Subtle motion was corrected using a deformable registration algorithm. Correlation with breath-holding was considered significant if p<0.001. Results: The percentage of the breast ROI with positive BOLD contrast measured by the two sequences were in agreement with a correlation coefficient of R=0.72 (p=0.02). While both sequences demonstrated areas with strong BOLD response, the response was more systematic throughout the breast for the SSFSE (T2) sequence (% breast with response in the same direction: 51.2%±0.7% for T2* vs. 68.1%±16% for T2). In addition, the T2 sequence was less prone to magnetic susceptibility artifacts, especially in presence of seroma, and provided a more robust image with little distortion or artifacts. Conclusion: A T2 SSFSE sequence shows promise for measuring BOLD contrast in the context of breast radiotherapy utilizing a breath hold technique. Further study in a larger patient cohort is warranted to better refine this novel technique.« less

The Carolina Center of Cancer Nanotechnology Excellence: Past Accomplishments and Future Perspectives

PubMed Central

JULIANO, R.L.; SUNNARBORG, S.; DESIMONE, J.; HAROON, Z.

2013-01-01

SUMMARY The Carolina Center of Cancer Nanotechnology Excellence (C-CCNE) is funded by the National Cancer Institute and is based at the University of North Carolina. The C-CCNE features interactions among physical and biological scientists in a series of projects and cores that work together to quickly harness innovations in nanotechnology for the early diagnosis and treatment of cancer. Two key focus areas of the C-CCNE are, first the selective delivery of drugs and imaging agents utilizing advanced nanoparticle technology, and second novel approaches to imaging and radiotherapy utilizing carbon nanotube based X-ray sources. PMID:21182415

Systematic feasibility analysis of a quantitative elasticity estimation for breast anatomy using supine/prone patient postures.

PubMed

Hasse, Katelyn; Neylon, John; Sheng, Ke; Santhanam, Anand P

2016-03-01

Breast elastography is a critical tool for improving the targeted radiotherapy treatment of breast tumors. Current breast radiotherapy imaging protocols only involve prone and supine CT scans. There is a lack of knowledge on the quantitative accuracy with which breast elasticity can be systematically measured using only prone and supine CT datasets. The purpose of this paper is to describe a quantitative elasticity estimation technique for breast anatomy using only these supine/prone patient postures. Using biomechanical, high-resolution breast geometry obtained from CT scans, a systematic assessment was performed in order to determine the feasibility of this methodology for clinically relevant elasticity distributions. A model-guided inverse analysis approach is presented in this paper. A graphics processing unit (GPU)-based linear elastic biomechanical model was employed as a forward model for the inverse analysis with the breast geometry in a prone position. The elasticity estimation was performed using a gradient-based iterative optimization scheme and a fast-simulated annealing (FSA) algorithm. Numerical studies were conducted to systematically analyze the feasibility of elasticity estimation. For simulating gravity-induced breast deformation, the breast geometry was anchored at its base, resembling the chest-wall/breast tissue interface. Ground-truth elasticity distributions were assigned to the model, representing tumor presence within breast tissue. Model geometry resolution was varied to estimate its influence on convergence of the system. A priori information was approximated and utilized to record the effect on time and accuracy of convergence. The role of the FSA process was also recorded. A novel error metric that combined elasticity and displacement error was used to quantify the systematic feasibility study. For the authors' purposes, convergence was set to be obtained when each voxel of tissue was within 1 mm of ground-truth deformation. The authors' analyses showed that a ∼97% model convergence was systematically observed with no-a priori information. Varying the model geometry resolution showed no significant accuracy improvements. The GPU-based forward model enabled the inverse analysis to be completed within 10-70 min. Using a priori information about the underlying anatomy, the computation time decreased by as much as 50%, while accuracy improved from 96.81% to 98.26%. The use of FSA was observed to allow the iterative estimation methodology to converge more precisely. By utilizing a forward iterative approach to solve the inverse elasticity problem, this work indicates the feasibility and potential of the fast reconstruction of breast tissue elasticity using supine/prone patient postures.

The combined use of surgery and radiotherapy to treat patients with epidural cord compression due to metastatic disease: a cost-utility analysis

PubMed Central

Furlan, Julio C.; Chan, Kelvin K.-W.; Sandoval, Guillermo A.; Lam, Kenneth C. K.; Klinger, Christopher A.; Patchell, Roy A.; Laporte, Audrey; Fehlings, Michael G.

2012-01-01

Neoplastic metastatic epidural spinal cord compression is a common complication of cancer that causes pain and progressive neurologic impairment. The previous standard treatment for this condition involved corticosteroids and radiotherapy (RT). Direct decompressive surgery with postoperative radiotherapy (S + RT) is now increasingly being chosen by clinicians to significantly improve patients’ ability to walk and reduce their need for opioid analgesics and corticosteroids. A cost-utility analysis was conducted to compare S + RT with RT alone based on the landmark randomized clinical trial by Patchell et al. (2005). It was performed from the perspective of the Ontario Ministry of Health and Long-Term Care. Ontario-based costs were adjusted to 2010 US dollars. S + RT is more costly but also more effective than corticosteroids and RT alone, with an incremental cost-effectiveness ratio of US$250 307 per quality-adjusted life year (QALY) gained. First order probabilistic sensitivity analysis revealed that the probability of S + RT being cost-effective is 18.11%. The cost-effectiveness acceptability curve showed that there is a 91.11% probability of S + RT being cost-effective over RT alone at a willingness-to-pay of US$1 683 000 per QALY. In practice, the results of our study indicate that, by adopting the S + RT strategy, there would still be a chance of 18.11% of not paying extra at a willingness-to-pay of US$50 000 per QALY. Those results are sensitive to the costs of hospice palliative care. Our results suggest that adopting a standard S + RT approach for patients with MSCC is likely to increase health care costs but would result in improved outcomes. PMID:22505658

Developing and implementing a high precision setup system

NASA Astrophysics Data System (ADS)

Peng, Lee-Cheng

The demand for high-precision radiotherapy (HPRT) was first implemented in stereotactic radiosurgery using a rigid, invasive stereotactic head frame. Fractionated stereotactic radiotherapy (SRT) with a frameless device was developed along a growing interest in sophisticated treatment with a tight margin and high-dose gradient. This dissertation establishes the complete management for HPRT in the process of frameless SRT, including image-guided localization, immobilization, and dose evaluation. The most ideal and precise positioning system can allow for ease of relocation, real-time patient movement assessment, high accuracy, and no additional dose in daily use. A new image-guided stereotactic positioning system (IGSPS), the Align RT3C 3D surface camera system (ART, VisionRT), which combines 3D surface images and uses a real-time tracking technique, was developed to ensure accurate positioning at the first place. The uncertainties of current optical tracking system, which causes patient discomfort due to additional bite plates using the dental impression technique and external markers, are found. The accuracy and feasibility of ART is validated by comparisons with the optical tracking and cone-beam computed tomography (CBCT) systems. Additionally, an effective daily quality assurance (QA) program for the linear accelerator and multiple IGSPSs is the most important factor to ensure system performance in daily use. Currently, systematic errors from the phantom variety and long measurement time caused by switching phantoms were discovered. We investigated the use of a commercially available daily QA device to improve the efficiency and thoroughness. Reasonable action level has been established by considering dosimetric relevance and clinic flow. As for intricate treatments, the effect of dose deviation caused by setup errors remains uncertain on tumor coverage and toxicity on OARs. The lack of adequate dosimetric simulations based on the true treatment coordinates from the treatment planning system (TPS) has limited adaptive treatments. A reliable and accurate dosimetric simulation using TPS and in-house software in uncorrected errors has been developed. In SRT, the calculated dose deviation is compared to the original treatment dose with the dose-volume histogram to investigate the dose effect of rotational errors. In summary, this work performed a quality assessment to investigate the overall accuracy of current setup systems. To reach the ideal HPRT, the reliable dosimetric simulation, an effective daily QA program and effective, precise setup systems were developed and validated.

Teaching Cancer Patients the Value of Correct Positioning During Radiotherapy Using Visual Aids and Practical Exercises.

PubMed

Hansen, Helle; Nielsen, Berit Kjærside; Boejen, Annette; Vestergaard, Anne

2018-06-01

The aim of this study was to investigate if teaching patients about positioning before radiotherapy treatment would (a) reduce the residual rotational set-up errors, (b) reduce the number of repositionings and (c) improve patients' sense of control by increasing self-efficacy and reducing distress. Patients were randomized to either standard care (control group) or standard care and a teaching session combining visual aids and practical exercises (intervention group). Daily images from the treatment sessions were evaluated off-line. Both groups filled in a questionnaire before and at the end of the treatment course on various aspects of cooperation with the staff regarding positioning. Comparisons of residual rotational set-up errors showed an improvement in the intervention group compared to the control group. No significant differences were found in number of repositionings, self-efficacy or distress. Results show that it is possible to teach patients about positioning and thereby improve precision in positioning. Teaching patients about positioning did not seem to affect self-efficacy or distress scores at baseline and at the end of the treatment course.

Implementation of small field radiotherapy dosimetry for spinal metastase case

NASA Astrophysics Data System (ADS)

Rofikoh, Wibowo, W. E.; Pawiro, S. A.

2017-07-01

The main objective of this study was to know dose profile of small field radiotherapy in the spinal metastase case with source axis distance (SAD) techniques. In addition, we evaluated and compared the dose planning of stereotactic body radiation therapy (SBRT) and conventional techniques to measurements with Exradin A16 and Gafchromic EBT3 film dosimeters. The results showed that film EBT3 had a highest precision and accuracy with the average of the standard deviation of ±1.7 and maximum discrepancy of 2.6 %. In addition, the average value of Full Wave Half Maximum (FWHM) and its largest deviation in small field size of 0.8 x 0.8 cm2 are 0.82 cm and 16.3 % respectively, while it was found around 2.36 cm and 3 % for the field size of 2.4 x 2.4 cm2. The comparison between penumbra width and the collimation was around of 37.1 % for the field size of 0.8 x 0.8 cm2, while it was found of 12.4 % for the field size of 2.4 x 2.4 cm2.

Lowering Whole-Body Radiation Doses in Pediatric Intensity-Modulated Radiotherapy Through the Use of Unflattened Photon Beams;Flattening filter; Pediatric; Intensity-modulated radiotherapy; Second cancers; Radiation-induced malignancies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cashmore, Jason, E-mail: Jason.cashmore@uhb.nhs.uk; Ramtohul, Mark; Ford, Dan

Purpose: Intensity modulated radiotherapy (IMRT) has been linked with an increased risk of secondary cancer induction due to the extra leakage radiation associated with delivery of these techniques. Removal of the flattening filter offers a simple way of reducing head leakage, and it may be possible to generate equivalent IMRT plans and to deliver these on a standard linear accelerator operating in unflattened mode. Methods and Materials: An Elekta Precise linear accelerator has been commissioned to operate in both conventional and unflattened modes (energy matched at 6 MV) and a direct comparison made between the treatment planning and delivery ofmore » pediatric intracranial treatments using both approaches. These plans have been evaluated and delivered to an anthropomorphic phantom. Results: Plans generated in unflattened mode are clinically identical to those for conventional IMRT but can be delivered with greatly reduced leakage radiation. Measurements in an anthropomorphic phantom at clinically relevant positions including the thyroid, lung, ovaries, and testes show an average reduction in peripheral doses of 23.7%, 29.9%, 64.9%, and 70.0%, respectively, for identical plan delivery compared to conventional IMRT. Conclusions: IMRT delivery in unflattened mode removes an unwanted and unnecessary source of scatter from the treatment head and lowers leakage doses by up to 70%, thereby reducing the risk of radiation-induced second cancers. Removal of the flattening filter is recommended for IMRT treatments.« less

Extranodal natural killer/T-cell lymphoma: advances in the management.

PubMed

Jaccard, Arnaud; Hermine, Olivier

2011-09-01

Extranodal natural killer (NK)/T-cell lymphoma, nasal-type is a highly aggressive disease more frequent in Asia than in Western countries. There is no consensus treatment. The outcome depends on disease stage. Localized NK/T-cell lymphomas often respond to radiotherapy. In contrast, patients who have extensive disease or who relapse after radiotherapy have a very poor prognosis. Overall, long-term survival in these lymphomas tends to be inferior to that for other aggressive lymphomas. This review focuses on the new management modalities in light of advances in risk stratification, patient monitoring and treatment strategies. Many parameters have been reported to correlate with prognosis and new staging systems have been elaborated. Detecting Epstein-Barr virus (EBV) in the bone marrow is important for staging and measuring EBV DNA in the serum improved monitoring response to therapy. Radiation modalities have been precised and new strategies combining radiation and chemotherapy have been proposed for patients with localized disease. The particular efficacy of L-asparaginase in this disease has been confirmed and L-asparaginase-based regimens have been studied in prospective trials for patients with refractory, relapsing or disseminated disease with good results. Laboratory studies may point the way toward new therapeutic approaches. Early-stage disease is treated by involved-field radiotherapy with adjuvant chemotherapy. L-Asparaginase-containing regimens are the mainstay of treatment for advanced or disseminated disease. The role of targeted therapies, autologous and allogeneic haematopoietic stem cell transplantation is yet to be clearly defined.

PyCMSXiO: an external interface to script treatment plans for the Elekta® CMS XiO treatment planning system

NASA Astrophysics Data System (ADS)

Xing, Aitang; Arumugam, Sankar; Holloway, Lois; Goozee, Gary

2014-03-01

Scripting in radiotherapy treatment planning systems not only simplifies routine planning tasks but can also be used for clinical research. Treatment planning scripting can only be utilized in a system that has a built-in scripting interface. Among the commercially available treatment planning systems, Pinnacle (Philips) and Raystation (Raysearch Lab.) have inherent scripting functionality. CMS XiO (Elekta) is a widely used treatment planning system in radiotherapy centres around the world, but it does not have an interface that allows the user to script radiotherapy plans. In this study an external scripting interface, PyCMSXiO, was developed for XiO using the Python programming language. The interface was implemented as a python package/library using a modern object-oriented programming methodology. The package was organized as a hierarchy of different classes (objects). Each class (object) corresponds to a plan object such as the beam of a clinical radiotherapy plan. The interface of classes was implemented as object functions. Scripting in XiO using PyCMSXiO is comparable with Pinnacle scripting. This scripting package has been used in several research projects including commissioning of a beam model, independent three-dimensional dose verification for IMRT plans and a setup-uncertainty study. Ease of use and high-level functions provided in the package achieve a useful research tool. It was released as an open-source tool that may benefit the medical physics community.

The cost-effectiveness of routine postoperative radiotherapy after sector resection and axillary dissection for breast cancer stage I. Results from a randomized trial.

PubMed

Liljegren, G; Karlsson, G; Bergh, J; Holmberg, L

1997-08-01

Cost-effectiveness of routine postoperative radiotherapy after breast-conserving surgery has not been prospectively evaluated earlier. In times of rationing of medical resources, valid assessments of cost-effectiveness are important for rational allocation of resources. Cost and cost-effectiveness of routine postoperative radiotherapy was calculated in a prospective randomized trial comparing sector resection plus axillary dissection with (XRT group) or without (non-XRT group) postoperative radiotherapy in breast cancer stage I. Three hundred eighty-one patients were included. After a median follow-up of five years 43 local recurrences, six of them in the XRT-group occurred (P < 0.0001). No difference in regional and distant recurrence (P = 0.23) or survival (P = 0.44) was observed. Direct medical costs as well as indirect costs in terms of production lost during the treatment period and travel expenses were estimated from data in the medical records and the national insurance registry of each patient. Average costs of different treatment activities and measures were estimated for the XRT-group and the non-XRT group respectively. From these estimates differences in costs and effectiveness between the groups were calculated and marginal cost-effectiveness ratios were estimated. For the construction of QALYs each life-year was quality-adjusted by a utility value depending on which health state the patient was considered to perceive. Taking into account the cost of primary treatment, the cost of follow-up, the cost of treatment of a local recurrence, travel expenses and indirect costs (production lost) excluding costs for treatment of regional and distant recurrence the cost per avoided local recurrence at five years was SEK 337,727 ($44,438, Pounds 27,018). Adjustment for quality of life showed a cost for every gained QALY to be SEK approximately 1.6 million, ($210,526, Pounds 128,000), range SEK 0.2-3.9 million ($26,315-513,158, Pounds 16,000-312,000). The cost of routine postoperative radiotherapy after sector resection and axillary dissection in breast cancer stage I per avoided local recurrence and gained QALY is high. The cost per gained QALY show great variation depending on utility value, which in this study was derived from external observers and not from the patients themselves. These results stress the importance of identifying risk factors for local recurrence, better understanding of impact on quality of life of a local recurrence and adding cost evaluations to clinical trials in early breast cancer.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lupo, Janine M., E-mail: janine.lupo@ucsf.edu; Chuang, Cynthia F.; Chang, Susan M.

Purpose: To evaluate the intermediate- and long-term imaging manifestations of radiotherapy on normal-appearing brain tissue in patients with treated gliomas using 7T susceptibility-weighted imaging (SWI). Methods and Materials: SWI was performed on 25 patients with stable gliomas on a 7 Tesla magnet. Microbleeds were identified as discrete foci of susceptibility that did not correspond to vessels. The number of microbleeds was counted within and outside of the T2-hyperintense lesion. For 3 patients, radiation dosimetry maps were reconstructed and fused with the 7T SWI data. Results: Multiple foci of susceptibility consistent with microhemorrhages were observed in patients 2 years after chemoradiation.more » These lesions were not present in patients who were not irradiated. The prevalence of microhemorrhages increased with the time since completion of radiotherapy, and these lesions often extended outside the boundaries of the initial high-dose volume and into the contralateral hemisphere. Conclusions: High-field SWI has potential for visualizing the appearance of microbleeds associated with long-term effects of radiotherapy on brain tissue. The ability to visualize these lesions in normal-appearing brain tissue may be important in further understanding the utility of this treatment in patients with longer survival.« less

Evaluation of a combination tumor treatment using thermo-triggered liposomal drug delivery and carbon ion irradiation.

PubMed

Kokuryo, Daisuke; Aoki, Ichio; Yuba, Eiji; Kono, Kenji; Aoshima, Sadahito; Kershaw, Jeff; Saga, Tsuneo

2017-07-01

The combination of radiotherapy with chemotherapy is one of the most promising strategies for cancer treatment. Here, a novel combination strategy utilizing carbon ion irradiation as a high-linear energy transfer (LET) radiotherapy and a thermo-triggered nanodevice is proposed, and drug accumulation in the tumor and treatment effects are evaluated using magnetic resonance imaging relaxometry and immunohistology (Ki-67, n = 15). The thermo-triggered liposomal anticancer nanodevice was administered into colon-26 tumor-grafted mice, and drug accumulation and efficacy was compared for 6 groups (n = 32) that received or did not receive the radiotherapy and thermo trigger. In vivo quantitative R 1 maps visually demonstrated that the multimodal thermosensitive polymer-modified liposomes (MTPLs) can accumulate in the tumor tissue regardless of whether the region was irradiated by carbon ions or not. The tumor volume after combination treatment with carbon ion irradiation and MTPLs with thermo-triggering was significantly smaller than all the control groups at 8 days after treatment. The proposed strategy of combining high-LET irradiation and the nanodevice provides an effective approach for minimally invasive cancer treatment. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

WE-FG-201-01: Patient Centric Technologies for Diagnosis of Breast and Cervical Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramanujam, N.

Many low- and middle-income countries lack the resources and services to manage cancer, from screening and diagnosis to radiation therapy planning, treatment and quality assurance. The challenges in upgrading or introducing the needed services are enormous, and include severe shortages in equipment and trained staff. In this symposium, we will describe examples of technology and scientific research that have the potential to impact all these areas. These include: (1) the development of high-quality/low-cost colposcopes for cervical cancer screening, (2) the application of automated radiotherapy treatment planning to reduce staffing shortages, (3) the development of a novel radiotherapy treatment unit, andmore » (4) utilizing a cloud-based infrastructure to facilitate collaboration and QA. Learning Objectives: Understand some of the issues in cancer care in low- resource environments, including shortages in staff and equipment, and inadequate physical infrastructure for advanced radiotherapy. Understand the challenges in developing and deploying diagnostic and treatment devices and services for low-resource environments. Understand some of the emerging technological solutions for cancer management in LMICs. NCI; L. Court, NIH, Varian, Elekta; I. Feain, Ilana Feain is founder and CTO of Nano-X Pty Ltd.« less

WE-FG-201-00: High Impact Technologies for Low Resource Environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Many low- and middle-income countries lack the resources and services to manage cancer, from screening and diagnosis to radiation therapy planning, treatment and quality assurance. The challenges in upgrading or introducing the needed services are enormous, and include severe shortages in equipment and trained staff. In this symposium, we will describe examples of technology and scientific research that have the potential to impact all these areas. These include: (1) the development of high-quality/low-cost colposcopes for cervical cancer screening, (2) the application of automated radiotherapy treatment planning to reduce staffing shortages, (3) the development of a novel radiotherapy treatment unit, andmore » (4) utilizing a cloud-based infrastructure to facilitate collaboration and QA. Learning Objectives: Understand some of the issues in cancer care in low- resource environments, including shortages in staff and equipment, and inadequate physical infrastructure for advanced radiotherapy. Understand the challenges in developing and deploying diagnostic and treatment devices and services for low-resource environments. Understand some of the emerging technological solutions for cancer management in LMICs. NCI; L. Court, NIH, Varian, Elekta; I. Feain, Ilana Feain is founder and CTO of Nano-X Pty Ltd.« less

WE-FG-201-02: Automated Treatment Planning for Low-Resource Settings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Court, L.

Many low- and middle-income countries lack the resources and services to manage cancer, from screening and diagnosis to radiation therapy planning, treatment and quality assurance. The challenges in upgrading or introducing the needed services are enormous, and include severe shortages in equipment and trained staff. In this symposium, we will describe examples of technology and scientific research that have the potential to impact all these areas. These include: (1) the development of high-quality/low-cost colposcopes for cervical cancer screening, (2) the application of automated radiotherapy treatment planning to reduce staffing shortages, (3) the development of a novel radiotherapy treatment unit, andmore » (4) utilizing a cloud-based infrastructure to facilitate collaboration and QA. Learning Objectives: Understand some of the issues in cancer care in low- resource environments, including shortages in staff and equipment, and inadequate physical infrastructure for advanced radiotherapy. Understand the challenges in developing and deploying diagnostic and treatment devices and services for low-resource environments. Understand some of the emerging technological solutions for cancer management in LMICs. NCI; L. Court, NIH, Varian, Elekta; I. Feain, Ilana Feain is founder and CTO of Nano-X Pty Ltd.« less

A TCP model for external beam treatment of intermediate-risk prostate cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walsh, Sean; Putten, Wil van der

2013-03-15

Purpose: Biological models offer the ability to predict clinical outcomes. The authors describe a model to predict the clinical response of intermediate-risk prostate cancer to external beam radiotherapy for a variety of fractionation regimes. Methods: A fully heterogeneous population averaged tumor control probability model was fit to clinical outcome data for hyper, standard, and hypofractionated treatments. The tumor control probability model was then employed to predict the clinical outcome of extreme hypofractionation regimes, as utilized in stereotactic body radiotherapy. Results: The tumor control probability model achieves an excellent level of fit, R{sup 2} value of 0.93 and a root meanmore » squared error of 1.31%, to the clinical outcome data for hyper, standard, and hypofractionated treatments using realistic values for biological input parameters. Residuals Less-Than-Or-Slanted-Equal-To 1.0% are produced by the tumor control probability model when compared to clinical outcome data for stereotactic body radiotherapy. Conclusions: The authors conclude that this tumor control probability model, used with the optimized radiosensitivity values obtained from the fit, is an appropriate mechanistic model for the analysis and evaluation of external beam RT plans with regard to tumor control for these clinical conditions.« less

A phantom evaluation of a stereo-vision surface imaging system for radiotherapy patient setup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bert, Christoph; Metheany, Katherine G.; Doppke, Karen

2005-09-15

External beam irradiation requires precise positioning of the target relative to the treatment planning coordinate system. A three-dimensional (3D) surface imaging system for patient positioning has recently been installed in one of our linear accelerator (linac) rooms. The device utilizes close-range photogrammetry to generate a 3D model of the patient's surface. This geometric model can be made to look like a digital camera image if wrapped with a gray-level image (texture mapping) that shows surface coloration. The system is calibrated to the linac coordinate system and has been designed as a patient setup device. To reproduce patient position in fractionatedmore » radiotherapy, the daily patient surface model is registered to a previously recorded reference surface. Using surface registration, the system calculates the rigid-body transformation that minimizes the distance between the treatment and the reference surface models in a region-of-interest (ROI). This transformation is expressed as a set of new couch coordinates at which the patient position best matches with the reference data. If respiratory motion is a concern, the surface can be obtained with a gated acquisition at a specified phase of the respiratory cycle. To analyze the accuracy of the system, we performed several experiments with phantoms to assess stability, alignment accuracy, precision of the gating function, and surface topology. The reproducibility of surface measurements was tested for periods up to 57 h. Each recorded frame was registered to the reference surface to calculate the required couch adjustment. The system stability over this time period was better than 0.5 mm. To measure the accuracy of the system to detect and quantify patient shift relative to a reference image, we compared the shift detected by the surface imaging system with known couch transitions in a phantom study. The maximum standard deviation was 0.75 mm for the three translational degrees of freedom, and less than 0.1 deg. for each rotation. Surface model precision was tested against computed tomography (CT)-derived surface topology. The root-mean-square rms of the distance between the surfaces was 0.65 mm, excluding regions where beam hardening caused artifacts in the CT data. Measurements were made to test the gated acquisition mode. The time-dependent amplitude was measured with the surface imaging system and an established respiratory gating system based on infrared (IR)-marker detection. The measured motion trajectories from both systems were compared to the known trajectory of the stage. The standard deviations of the amplitude differences to the motor trajectory were 0.04 and 0.15 mm for the IR-marker system and the 3D surface imaging system, respectively. A limitation of the surface-imaging device is the frame rate of 6.5 Hz, because rapid changes of the motion trajectory cannot be detected. In conclusion, the system is accurate and sufficiently stable to be used in the clinic. The errors computed when comparing the surface model with CT geometry were submillimeter, and deviations in the alignment and gating-signal tests were of the same magnitude.« less

Nanomedicines for image-guided cancer therapy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Zheng, Jinzi

2016-09-01

Imaging technologies are being increasingly employed to guide the delivery of cancer therapies with the intent to increase their performance and efficacy. To date, many patients have benefited from image-guided treatments through prolonged survival and improvements in quality of life. Advances in nanomedicine have enabled the development of multifunctional imaging agents that can further increase the performance of image-guided cancer therapy. Specifically, this talk will focus on examples that demonstrate the benefits and application of nanomedicine in the context of image-guide surgery, personalized drug delivery, tracking of cell therapies and high precision radiotherapy delivery.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scarlatescu, Ioana, E-mail: scarlatescuioana@gmail.com; Avram, Calin N.; Virag, Vasile

In this paper we present one treatment plan for irradiation cases which involve a complex technique with multiple beams, using the 3D conformational technique. As the main purpose of radiotherapy is to administrate a precise dose into the tumor volume and protect as much as possible all the healthy tissues around it, for a case diagnosed with a primitive neuro ectoderm tumor, we have developed a new treatment plan, by controlling one of the two adjacent fields used at spinal field, in a way that avoids the fields superposition. Therefore, the risk of overdose is reduced by eliminating the fieldmore » divergence.« less

SU-E-J-45: Design and Study of An In-House Respiratory Gating Phantom Platform for Gated Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Senthilkumar, S

2014-06-01

Purpose: The main purpose of this work was to develop an in-house low cost respiratory motion phantom platform for testing the accuracy of the gated radiotherapy system and analyze the dosimetric difference during gated radiotherapy. Methods: An in-house respiratory motion platform(RMP) was designed and constructed for testing the targeting accuracy of respiratory tracking system. The RMP consist of acrylic Chest Wall Platform, 2 DC motors, 4 IR sensors, speed controller circuit, 2 LED and 2 moving rods inside the RMP. The velocity of the movement can be varied from 0 to 30 cycles per minute. The platform mounted to amore » base using precision linear bearings. The base and platform are made of clear, 15mm thick polycarbonate plastic and the linear ball bearings are oriented to restrict the platform to a movement of approximately 50mm up and down with very little friction. Results: The targeting accuracy of the respiratory tracking system was evaluated using phantom with and without respiratory movement with varied amplitude. We have found the 5% dose difference to the PTV during the movement in comparison with stable PTV. The RMP can perform sinusoidal motion in 1D with fixed peak to peak motion of 5 to 50mm and cycle interval from 2 to 6 seconds. The RMP was designed to be able to simulate the gross anatomical anterior posterior motion attributable to respiration-induced motion of the thoracic region. Conclusion: The unique RMP simulates breathing providing the means to create a comprehensive program for commissioning, training, quality assurance and dose verification of gated radiotherapy treatments. Create the anterior/posterior movement of a target over a 5 to 50 mm distance to replicate tumor movement. The targeting error of the respiratory tracking system is less than 1.0 mm which shows suitable for clinical treatment with highly performance.« less

The feasibility of using Microsoft Kinect v2 sensors during radiotherapy delivery.

PubMed

Edmunds, David M; Bashforth, Sophie E; Tahavori, Fatemeh; Wells, Kevin; Donovan, Ellen M

2016-11-08

Consumer-grade distance sensors, such as the Microsoft Kinect devices (v1 and v2), have been investigated for use as marker-free motion monitoring systems for radiotherapy. The radiotherapy delivery environment is challenging for such sen-sors because of the proximity to electromagnetic interference (EMI) from the pulse forming network which fires the magnetron and electron gun of a linear accelerator (linac) during radiation delivery, as well as the requirement to operate them from the control area. This work investigated whether using Kinect v2 sensors as motion monitors was feasible during radiation delivery. Three sensors were used each with a 12 m USB 3.0 active cable which replaced the supplied 3 m USB 3.0 cable. Distance output data from the Kinect v2 sensors was recorded under four condi-tions of linac operation: (i) powered up only, (ii) pulse forming network operating with no radiation, (iii) pulse repetition frequency varied between 6 Hz and 400 Hz, (iv) dose rate varied between 50 and 1450 monitor units (MU) per minute. A solid water block was used as an object and imaged when static, moved in a set of steps from 0.6 m to 2.0 m from the sensor and moving dynamically in two sinusoidal-like trajectories. Few additional image artifacts were observed and there was no impact on the tracking of the motion patterns (root mean squared accuracy of 1.4 and 1.1mm, respectively). The sensors' distance accuracy varied by 2.0 to 3.8 mm (1.2 to 1.4 mm post distance calibration) across the range measured; the precision was 1 mm. There was minimal effect from the EMI on the distance calibration data: 0 mm or 1 mm reported distance change (2 mm maximum change at one position). Kinect v2 sensors operated with 12 m USB 3.0 active cables appear robust to the radiotherapy treatment environment. © 2016 The Authors.

Dosimetric characterization of optically stimulated luminescence dosimeter with therapeutic photon beams for use in clinical radiotherapy measurements.

PubMed

Ponmalar, Retna; Manickam, Ravikumar; Ganesh, K M; Saminathan, Sathiyan; Raman, Arun; Godson, Henry Finlay

2017-01-01

The modern radiotherapy techniques impose new challenges for dosimetry systems with high precision and accuracy in in vivo and in phantom dosimetric measurements. The knowledge of the basic characterization of a dosimetric system before patient dose verification is crucial. This incites the investigation of the potential use of nanoDot optically stimulated luminescence dosimeter (OSLD) for application in radiotherapy with therapeutic photon beams. Measurements were carried out with nanoDot OSLDs to evaluate the dosimetric characteristics such as dose linearity, dependency on field size, dose rate, energy and source-to-surface distance (SSD), reproducibility, fading effect, reader stability, and signal depletion per read out with cobalt-60 (60 Co) beam, 6 and 18 MV therapeutic photon beams. The data acquired with OSLDs were validated with ionization chamber data where applicable. Good dose linearity was observed for doses up to 300 cGy and above which supralinear behavior. The standard uncertainty with field size observed was 1.10% ± 0.4%, 1.09% ± 0.34%, and 1.2% ± 0.26% for 6 MV, 18 MV, and 60 Co beam, respectively. The maximum difference with dose rate was 1.3% ± 0.4% for 6 MV and 1.4% ± 0.4% for 18 MV photon beams. The largest variation in SSD was 1.5% ± 1.2% for 60 Co, 1.5% ± 0.9% for 6 MV, and 1.5% ± 1.3% for 18 MV photon beams. The energy dependence of OSL response at 18 MV and 60 Co with 6 MV beam was 1.5% ± 0.7% and 1.7% ± 0.6%, respectively. In addition, good reproducibility, stability after the decay of transient signal, and predictable fading were observed. The results obtained in this study indicate the efficacy and suitability of nanoDot OSLD for dosimetric measurements in clinical radiotherapy.

TU-F-BRB-01: Resolving and Characterizing Breathing Motion for Radiotherapy with MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tryggestad, E.

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has highmore » temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant.« less

Regional radiation dose susceptibility within the parotid gland: Effects on salivary loss and recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, Haley, E-mail: hdclark@phas.ubc.ca; Reinsberg, Stefan; Hovan, Allan

2015-04-15

Purpose: Xerostomia is one of the most likely late toxic effects of radiotherapy treatment in patients with head-and-neck cancers. Modern treatment techniques can incorporate knowledge of complication risk into treatment plans. To this end, the authors attempt to quantify the regional radiotherapy dose-dependence of salivary output loss and recovery in a prospective study. Methods: Salivary output was collected from patients undergoing radiotherapy treatment for head-and-neck cancers at the BC Cancer Agency between February 2008 and May 2013. Regional dose-dependence (i.e., dose susceptibility) of loss and recovery is quantified using nonparametric (Spearman’s rank correlation coefficients, local linear regression) and parametric (least-summore » of squares, least-median of squares) techniques. Results: Salivary flow recovery was seen in 79 of 102 patients considered (p < 0.0001, Wilcoxon sign rank test). Output loss was strongly correlated with left- and right parotid combined dose φ = min (D{sub L},  45 Gy) + min (D{sub R},  45 Gy), and can be accurately predicted. Median early loss (three months) was 72% of baseline, while median overall loss (1 yr) was 56% of baseline. Fitting an exponential model to whole parotid yields dose sensitivities A{sub 3m} = 0.0604 Gy{sup −1} and A{sub 1y} = 0.0379 Gy{sup −1}. Recovery was not significantly associated with dose. Hints of lateral organ sub-segment dose–response dimorphism were observed. Conclusions: Sub-segmentation appears to predict neither loss nor recovery with any greater precision than whole parotid mean dose, though it is not any worse. Sparing the parotid to a combined dose φ of <50 Gy is recommended for a patient to keep ≈40% of baseline function and thus avoid severe xerostomia at 12 months post-treatment. It seems unlikely that a population’s mean recovery will exceed 20%–30% of baseline output at 1 yr after radiotherapy treatment using current (whole-organ based) clinical guidelines.« less

Deformable Dose Reconstruction to Optimize the Planning and Delivery of Liver Cancer Radiotherapy

NASA Astrophysics Data System (ADS)

Velec, Michael

The precise delivery of radiation to liver cancer patients results in improved control with higher tumor doses and minimized normal tissues doses. A margin of normal tissue around the tumor requires irradiation however to account for treatment delivery uncertainties. Daily image-guidance allows targeting of the liver, a surrogate for the tumor, to reduce geometric errors. However poor direct tumor visualization, anatomical deformation and breathing motion introduce uncertainties between the planned dose, calculated on a single pre-treatment computed tomography image, and the dose that is delivered. A novel deformable image registration algorithm based on tissue biomechanics was applied to previous liver cancer patients to track targets and surrounding organs during radiotherapy. Modeling these daily anatomic variations permitted dose accumulation, thereby improving calculations of the delivered doses. The accuracy of the algorithm to track dose was validated using imaging from a deformable, 3-dimensional dosimeter able to optically track absorbed dose. Reconstructing the delivered dose revealed that 70% of patients had substantial deviations from the initial planned dose. An alternative image-guidance technique using respiratory-correlated imaging was simulated, which reduced both the residual tumor targeting errors and the magnitude of the delivered dose deviations. A planning and delivery strategy for liver radiotherapy was then developed that minimizes the impact of breathing motion, and applied a margin to account for the impact of liver deformation during treatment. This margin is 38% smaller on average than the margin used clinically, and permitted an average dose-escalation to liver tumors of 9% for the same risk of toxicity. Simulating the delivered dose with deformable dose reconstruction demonstrated the plans with smaller margins were robust as 90% of patients' tumors received the intended dose. This strategy can be readily implemented with widely available technologies and thus can potentially improve local control for liver cancer patients receiving radiotherapy.

On the use of particle filters for electromagnetic tracking in high dose rate brachytherapy

NASA Astrophysics Data System (ADS)

Götz, Th I.; Lahmer, G.; Brandt, T.; Kallis, K.; Strnad, V.; Bert, Ch; Hensel, B.; Tomé, A. M.; Lang, E. W.

2017-10-01

Modern radiotherapy of female breast cancers often employs high dose rate brachytherapy, where a radioactive source is moved inside catheters, implanted in the female breast, according to a prescribed treatment plan. Source localization relative to the patient’s anatomy is determined with solenoid sensors whose spatial positions are measured with an electromagnetic tracking system. Precise sensor dwell position determination is of utmost importance to assure irradiation of the cancerous tissue according to the treatment plan. We present a hybrid data analysis system which combines multi-dimensional scaling with particle filters to precisely determine sensor dwell positions in the catheters during subsequent radiation treatment sessions. Both techniques are complemented with empirical mode decomposition for the removal of superimposed breathing artifacts. We show that the hybrid model robustly and reliably determines the spatial positions of all catheters used during the treatment and precisely determines any deviations of actual sensor dwell positions from the treatment plan. The hybrid system only relies on sensor positions measured with an EMT system and relates them to the spatial positions of the implanted catheters as initially determined with a computed x-ray tomography.

A novel design of the high-precision magnetic locator with three-dimension measurement capability applying dynamically sensing mechanism

NASA Astrophysics Data System (ADS)

Huang, Wen-Nan; Chen, Po-Shen; Chen, Mu-Ping; Teng, Ching-Cheng

2006-09-01

A novel design of the magnetic locator, for obtaining the high-precision measurement information of variety of the buried metal pipes, is presented in this paper. The concept of dynamically sensing mechanism, including the vibrating and moving devices, proposed herein is a simple and effective way to improve the precision of three-dimension location sensing for the underground utilities. Based on the primary magnetism of Lenz's law and Faraday's law, the functions of the amplifying effect for the sensing magnetic signals, as well as the distinguishing effect by the simple filtering algorithms embedded in processing programs, are achieved while the relatively strong noise exists. The verification results of these integration designs demonstrate the effectiveness both by precise locating for the buried utility, and accurate measurement for the depth.

Recurrent high-grade glioma.

PubMed

Quant, Eudocia C; Drappatz, Jan; Wen, Patrick Y; Norden, Andrew D

2010-07-01

Opinions vary on the best treatment options for recurrent high-grade glioma. Some argue that bevacizumab should become standard of care for patients with recurrent glioblastoma, especially in light of recent FDA approval for this indication. However, this opinion is not uniformly accepted. Age, performance status, histology, tumor size and location, O6-methylguanine-DNA methyltransferase (MGMT) methylation status for glioblastoma, 1p/19q status for oligodendroglial tumors, and the number and types of prior therapies are important considerations. In addition, recurrent disease must be distinguished from "pseudoprogression" due to treatment effects. Enrollment in a clinical trial is the optimal choice for most patients with recurrent high-grade glioma after failure of radiation therapy and temozolomide. For patients who are ineligible or do not have access to clinical trials, then either bevacizumab monotherapy or bevacizumab in combination with a second agent such as irinotecan is recommended. Involved-field external beam radiation should be considered for patients with anaplastic gliomas who have not received radiation. For patients with anaplastic astrocytoma who progress after radiotherapy, temozolomide may be used. For patients with anaplastic oligodendroglioma who progress after radiotherapy, PCV chemotherapy and temozolomide are options. Oligodendroglial tumors with 1p/19q deletions are more likely to respond to treatment. In the past, carmustine was commonly used to treat recurrent high-grade glioma, but the utility of carmustine in the modern era is unknown because most studies were performed prior to the widespread use of temozolomide. High-precision re-irradiation such as stereotactic radiosurgery is another option in high-grade glioma, especially for patients with poor bone marrow reserve or inability to tolerate chemotherapy, but there is a paucity of studies with adequate controls. Surgery may be useful as adjuvant treatment for patients with symptoms due to mass effect or for patients requiring definitive histopathology, but it generally should be combined with another treatment modality. Emerging therapies, including dose-intense temozolomide regimens, targeted molecular inhibitors, other antiangiogenic therapies, viral gene therapies, immunotherapies, and convection-enhanced delivery of targeted immunotoxins, are still under investigation.

SU-F-P-09: A Global Medical Physics Collaboration for Implementation of Modern Radiotherapy in Botswana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makufa, R; Bvochora-Nsingo, M; Karumekayi, T

2016-06-15

Purpose: The global burden of cancer is considerable, particularly in low and middle-income countries. Massachusetts General Hospital (MGH) and Botswana-Harvard AIDS Institute have partnered with the oncology community and government of Botswana to form BOTSOGO (BOTSwana Oncology Global Outreach) to address the rising burden of cancer in Botswana. Currently, radiation therapy (RT) is only available at a single linear accelerator (LINAC) in Gaborone Private Hospital (GPH). BOTSOGO worked to limit the absence of RT during a LINAC upgrade and ensure a safe transition to modern radiotherapy techniques. Methods: The existing Elekta Precise LINAC was decommissioned in November 2015 and replacedmore » with a new Elekta VERSA-HD with IMRT/VMAT/CBCT capability. Upgraded treatment planning and record-and-verify systems were also installed. Physicists from GPH and MGH collaborated during an intensive on-site visit in Botswana during the commissioning process. Measurements were performed using newly purchased Sun Nuclear equipment. Photon beams were matched with an existing model to minimize the time needed for beam modeling and machine down time. Additional remote peer review was also employed. Independent dosimetry was performed by irradiating OSLDs, which were subsequently analyzed at MGH. Results: Photon beam quality agreed with reference data within 0.2%. Electron beam data agreed with example clinical data within 3%. Absolute dose calibration was performed using both IAEA and AAPM protocols. Absolute dose measurements with OSLDs agreed within 5%. Quentry cloud-based software was installed to facilitate remote review of treatment plans. Patient treatments resumed in February 2016. The time without RT was reduced, therefore likely resulting in reduced patient morbidity/mortality. Conclusion: A global physics collaboration was utilized to commission a modern LINAC in a resource-constrained setting. This can be a useful model in other areas with limited resources. Further use of technology and on-site exchanges will facilitate the introduction of more advanced techniques in Botswana. We acknowledge funding support from the AAPM International Educational Activities Committee and the NCI Federal Share Proton Beam Program Income Grant.« less

SU-E-J-116: Uncertainties Associated with Dose Summation of High-Dose Rate Brachytherapy and Intensity Modulated Radiotherapy for Gynecological Cases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kauweloa, K; Bergamo, A; Gutierrez, A

Purpose: Determining the cumulative dose distribution (CDD) for gynecological patients treated with both high-dose rate (HDR) brachytherapy and intensity-modulated radiotherapy (IMRT) is challenging. The purpose of this work is to study the uncertainty of performing this with a structure-guided deformable (SGD) approach in Velocity. Methods: For SGD, the Hounsfield units inside specified contours are overridden to set uniform values. Deformable image registration (DIR) is the run on these process images, which forces the DIR to focus on these contour boundaries. 18 gynecological cancer patients were used in this study. The original bladder and rectum planning contours for these patients weremore » used to drive the SGD. A second set of contours were made of the bladder by the same person with the intent of carefully making them completely consistent with each other. This second set was utilized to evaluate the spatial accuracy of the SGD. The determined spatial accuracy was then multiplied by the local dose gradient to determine a dose uncertainty associated with the SGD dose warping. The normal tissue complication probability (NTCP) was then calculated for each dose volume histogram (DVH) that included four different probabilistic uncertainties associated with the spatial errors (e.g., 68.3% and 95.4%). Results: The NTCPs for each DVH (e.g., NTCP-−95.4%, NTCP-−68.3%, NTCP-68.3%, NTCP-95.4%) differed amongst patients. All patients had an NTCP-−95.4% close to 0%, while NTCP-95.4% ranged from 0.67% to 100%. Nine patients had an NTCP-−95.4% less than 50% while the remaining nine patients had NTCP-95.4% greater than 50%. Conclusion: The uncertainty associated with this CDD technique renders a large NTCP uncertainty. Thus, it is currently not practical for clinical use. The two ways to improve this would be to use more precise contours to drive the SGD and to use a more accurate DIR algorithm.« less

Non-rigid CT/CBCT to CBCT registration for online external beam radiotherapy guidance

NASA Astrophysics Data System (ADS)

Zachiu, Cornel; de Senneville, Baudouin Denis; Tijssen, Rob H. N.; Kotte, Alexis N. T. J.; Houweling, Antonetta C.; Kerkmeijer, Linda G. W.; Lagendijk, Jan J. W.; Moonen, Chrit T. W.; Ries, Mario

2018-01-01

Image-guided external beam radiotherapy (EBRT) allows radiation dose deposition with a high degree of accuracy and precision. Guidance is usually achieved by estimating the displacements, via image registration, between cone beam computed tomography (CBCT) and computed tomography (CT) images acquired at different stages of the therapy. The resulting displacements are then used to reposition the patient such that the location of the tumor at the time of treatment matches its position during planning. Moreover, ongoing research aims to use CBCT-CT image registration for online plan adaptation. However, CBCT images are usually acquired using a small number of x-ray projections and/or low beam intensities. This often leads to the images being subject to low contrast, low signal-to-noise ratio and artifacts, which ends-up hampering the image registration process. Previous studies addressed this by integrating additional image processing steps into the registration procedure. However, these steps are usually designed for particular image acquisition schemes, therefore limiting their use on a case-by-case basis. In the current study we address CT to CBCT and CBCT to CBCT registration by the means of the recently proposed EVolution registration algorithm. Contrary to previous approaches, EVolution does not require the integration of additional image processing steps in the registration scheme. Moreover, the algorithm requires a low number of input parameters, is easily parallelizable and provides an elastic deformation on a point-by-point basis. Results have shown that relative to a pure CT-based registration, the intrinsic artifacts present in typical CBCT images only have a sub-millimeter impact on the accuracy and precision of the estimated deformation. In addition, the algorithm has low computational requirements, which are compatible with online image-based guidance of EBRT treatments.

Pituitary adenoma with seizures: PET demonstration of reduced glucose utilization in the medial temporal lobe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bairamian, D.; Di Chiro, G.; Blume, H.

1986-05-01

A patient with a benign chromophobe adenoma, who had incomplete surgical removal followed by radiotherapy, continued to have epileptic seizures up to two or three times a day. She was studied with positron emission tomography using /sup 18/F-2-deoxyglucose (FDG). This technique showed a high level of glucose utilization in the area of the operated tumor but also clear reduction of glucose utilization in the left medial temporal region adjacent to the sella and the scar tissue from the neoplasm. This area of reduced glucose utilization corresponded well to the same finding observed in other patients with complex partial epilepsy. Amore » left temporal anterior lobectomy was carried out followed by improved control of the epilepsy. Positron emission tomography using FDG, together with electrophysiological examinations, may assist in the management of epilepsy related to pituitary tumors.« less

Precision liquid level sensor

DOEpatents

Field, M.E.; Sullivan, W.H.

A precision liquid level sensor utilizes a balanced bridge, each arm including an air dielectric line. Changes in liquid level along one air dielectric line imbalance the bridge and create a voltage which is directly measurable across the bridge.

Precision diagnostics: moving towards protein biomarker signatures of clinical utility in cancer.

PubMed

Borrebaeck, Carl A K

2017-03-01

Interest in precision diagnostics has been fuelled by the concept that early detection of cancer would benefit patients; that is, if detected early, more tumours should be resectable and treatment more efficacious. Serum contains massive amounts of potentially diagnostic information, and affinity proteomics has risen as an accurate approach to decipher this, to generate actionable information that should result in more precise and evidence-based options to manage cancer. To achieve this, we need to move from single to multiplex biomarkers, a so-called signature, that can provide significantly increased diagnostic accuracy. This Opinion article focuses on the progress being made in identifying protein biomarker signatures of clinical utility, using blood-based proteomics.

On the use of an analytic source model for dose calculations in precision image-guided small animal radiotherapy.

PubMed

Granton, Patrick V; Verhaegen, Frank

2013-05-21

Precision image-guided small animal radiotherapy is rapidly advancing through the use of dedicated micro-irradiation devices. However, precise modeling of these devices in model-based dose-calculation algorithms such as Monte Carlo (MC) simulations continue to present challenges due to a combination of very small beams, low mechanical tolerances on beam collimation, positioning and long calculation times. The specific intent of this investigation is to introduce and demonstrate the viability of a fast analytical source model (AM) for use in either investigating improvements in collimator design or for use in faster dose calculations. MC models using BEAMnrc were developed for circular and square fields sizes from 1 to 25 mm in diameter (or side) that incorporated the intensity distribution of the focal spot modeled after an experimental pinhole image. These MC models were used to generate phase space files (PSFMC) at the exit of the collimators. An AM was developed that included the intensity distribution of the focal spot, a pre-calculated x-ray spectrum, and the collimator-specific entrance and exit apertures. The AM was used to generate photon fluence intensity distributions (ΦAM) and PSFAM containing photons radiating at angles according to the focal spot intensity distribution. MC dose calculations using DOSXYZnrc in a water and mouse phantom differing only by source used (PSFMC versus PSFAM) were found to agree within 7% and 4% for the smallest 1 and 2 mm collimator, respectively, and within 1% for all other field sizes based on depth dose profiles. PSF generation times were approximately 1200 times faster for the smallest beam and 19 times faster for the largest beam. The influence of the focal spot intensity distribution on output and on beam shape was quantified and found to play a significant role in calculated dose distributions. Beam profile differences due to collimator alignment were found in both small and large collimators sensitive to shifts of 1 mm with respect to the central axis.

Preoperative radiotherapy for rectal cancer: a comparative study of quality control adherence at two cancer hospitals in Spain and Poland

PubMed Central

Fundowicz, Magdalena; Macia, Miguel; Marin, Susanna; Bogusz-Czerniewicz, Marta; Konstanty, Ewelina; Modolel, Ignaci; Malicki, Julian; Guedea, Ferran

2014-01-01

Background We performed a clinical audit of preoperative rectal cancer treatment at two European radiotherapy centres (Poland and Spain). The aim was to independently verify adherence to a selection of indicators of treatment quality and to identify any notable inter-institutional differences. Methods A total of 162 patients, in Catalan Institute of Oncology (ICO) 68 and in Greater Poland Cancer Centre (GPCC) 94, diagnosed with locally advanced rectal cancer and treated with preoperative radiotherapy or radio-chemotherapy were included in retrospective study. A total of 7 quality control measures were evaluated: waiting time, multidisciplinary treatment approach, portal verification, in vivo dosimetry, informed consent, guidelines for diagnostics and therapy, and patient monitoring during treatment. Results Several differences were observed. Waiting time from pathomorphological diagnosis to initial consultation was 31 (ICO) vs. 8 (GPCC) days. Waiting time from the first visit to the beginning of the treatment was twice as long at the ICO. At the ICO, 82% of patient experienced treatment interruptions. The protocol for portal verification was the same at both institutions. In vivo dosimetry is not used for this treatment localization at the ICO. The ICO utilizes locally-developed guidelines for diagnostics and therapy, while the GPCC is currently developing its own guidelines. Conclusions An independent external clinical audit is an excellent approach to identifying and resolving deficiencies in quality control procedures. We identified several procedures amenable to improvement. Both institutions have since implemented changes to improve quality standards. We believe that all radiotherapy centres should perform a comprehensive clinical audit to identify and rectify deficiencies. PMID:24991212

Preoperative radiotherapy for rectal cancer: a comparative study of quality control adherence at two cancer hospitals in Spain and Poland.

PubMed

Fundowicz, Magdalena; Macia, Miguel; Marin, Susanna; Bogusz-Czerniewicz, Marta; Konstanty, Ewelina; Modolel, Ignaci; Malicki, Julian; Guedea, Ferran

2014-06-01

We performed a clinical audit of preoperative rectal cancer treatment at two European radiotherapy centres (Poland and Spain). The aim was to independently verify adherence to a selection of indicators of treatment quality and to identify any notable inter-institutional differences. A total of 162 patients, in Catalan Institute of Oncology (ICO) 68 and in Greater Poland Cancer Centre (GPCC) 94, diagnosed with locally advanced rectal cancer and treated with preoperative radiotherapy or radio-chemotherapy were included in retrospective study. A total of 7 quality control measures were evaluated: waiting time, multidisciplinary treatment approach, portal verification, in vivo dosimetry, informed consent, guidelines for diagnostics and therapy, and patient monitoring during treatment. Several differences were observed. Waiting time from pathomorphological diagnosis to initial consultation was 31 (ICO) vs. 8 (GPCC) days. Waiting time from the first visit to the beginning of the treatment was twice as long at the ICO. At the ICO, 82% of patient experienced treatment interruptions. The protocol for portal verification was the same at both institutions. In vivo dosimetry is not used for this treatment localization at the ICO. The ICO utilizes locally-developed guidelines for diagnostics and therapy, while the GPCC is currently developing its own guidelines. An independent external clinical audit is an excellent approach to identifying and resolving deficiencies in quality control procedures. We identified several procedures amenable to improvement. Both institutions have since implemented changes to improve quality standards. We believe that all radiotherapy centres should perform a comprehensive clinical audit to identify and rectify deficiencies.

WE-EF-BRD-01: Past, Present and Future: MRI-Guided Radiotherapy From 2005 to 2025

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lagendijk, J.

MRI-guided treatment is a growing area of medicine, particularly in radiotherapy and surgery. The exquisite soft tissue anatomic contrast offered by MRI, along with functional imaging, makes the use of MRI during therapeutic procedures very attractive. Challenging the utility of MRI in the therapy room are many issues including the physics of MRI and the impact on the environment and therapeutic instruments, the impact of the room and instruments on the MRI; safety, space, design and cost. In this session, the applications and challenges of MRI-guided treatment will be described. The session format is: Past, present and future: MRI-guided radiotherapymore » from 2005 to 2025: Jan Lagendijk Battling Maxwell’s equations: Physics challenges and solutions for hybrid MRI systems: Paul Keall I want it now!: Advances in MRI acquisition, reconstruction and the use of priors to enable fast anatomic and physiologic imaging to inform guidance and adaptation decisions: Yanle Hu MR in the OR: The growth and applications of MRI for interventional radiology and surgery: Rebecca Fahrig Learning Objectives: To understand the history and trajectory of MRI-guided radiotherapy To understand the challenges of integrating MR imaging systems with linear accelerators To understand the latest in fast MRI methods to enable the visualisation of anatomy and physiology on radiotherapy treatment timescales To understand the growing role and challenges of MRI for image-guided surgical procedures My disclosures are publicly available and updated at: http://sydney.edu.au/medicine/radiation-physics/about-us/disclosures.php.« less

Knowledge-based computer systems for radiotherapy planning.

PubMed

Kalet, I J; Paluszynski, W

1990-08-01

Radiation therapy is one of the first areas of clinical medicine to utilize computers in support of routine clinical decision making. The role of the computer has evolved from simple dose calculations to elaborate interactive graphic three-dimensional simulations. These simulations can combine external irradiation from megavoltage photons, electrons, and particle beams with interstitial and intracavitary sources. With the flexibility and power of modern radiotherapy equipment and the ability of computer programs that simulate anything the machinery can do, we now face a challenge to utilize this capability to design more effective radiation treatments. How can we manage the increased complexity of sophisticated treatment planning? A promising approach will be to use artificial intelligence techniques to systematize our present knowledge about design of treatment plans, and to provide a framework for developing new treatment strategies. Far from replacing the physician, physicist, or dosimetrist, artificial intelligence-based software tools can assist the treatment planning team in producing more powerful and effective treatment plans. Research in progress using knowledge-based (AI) programming in treatment planning already has indicated the usefulness of such concepts as rule-based reasoning, hierarchical organization of knowledge, and reasoning from prototypes. Problems to be solved include how to handle continuously varying parameters and how to evaluate plans in order to direct improvements.

A brachytherapy photon radiation quality index Q(BT) for probe-type dosimetry.

PubMed

Quast, Ulrich; Kaulich, Theodor W; Álvarez-Romero, José T; Carlsson Tedgren, Sa; Enger, Shirin A; Medich, David C; Mourtada, Firas; Perez-Calatayud, Jose; Rivard, Mark J; Zakaria, G Abu

2016-06-01

In photon brachytherapy (BT), experimental dosimetry is needed to verify treatment plans if planning algorithms neglect varying attenuation, absorption or scattering conditions. The detector's response is energy dependent, including the detector material to water dose ratio and the intrinsic mechanisms. The local mean photon energy E¯(r) must be known or another equivalent energy quality parameter used. We propose the brachytherapy photon radiation quality indexQ(BT)(E¯), to characterize the photon radiation quality in view of measurements of distributions of the absorbed dose to water, Dw, around BT sources. While the external photon beam radiotherapy (EBRT) radiation quality index Q(EBRT)(E¯)=TPR10(20)(E¯) is not applicable to BT, the authors have applied a novel energy dependent parameter, called brachytherapy photon radiation quality index, defined as Q(BT)(E¯)=Dprim(r=2cm,θ0=90°)/Dprim(r0=1cm,θ0=90°), utilizing precise primary absorbed dose data, Dprim, from source reference databases, without additional MC-calculations. For BT photon sources used clinically, Q(BT)(E¯) enables to determine the effective mean linear attenuation coefficient μ¯(E) and thus the effective energy of the primary photons Eprim(eff)(r0,θ0) at the TG-43 reference position Pref(r0=1cm,θ0=90°), being close to the mean total photon energy E¯tot(r0,θ0). If one has calibrated detectors, published E¯tot(r) and the BT radiation quality correction factor [Formula: see text] for different BT radiation qualities Q and Q0, the detector's response can be determined and Dw(r,θ) measured in the vicinity of BT photon sources. This novel brachytherapy photon radiation quality indexQ(BT) characterizes sufficiently accurate and precise the primary photon's penetration probability and scattering potential. Copyright © 2016. Published by Elsevier Ltd.

Visualization of gene expression in the live subject using the Na/I symporter as a reporter gene: applications in biotherapy

PubMed Central

Baril, Patrick; Martin-Duque, Pilar; Vassaux, Georges

2010-01-01

Biotherapies involve the utilization of antibodies, genetically modified viruses, bacteria or cells for therapeutic purposes. Molecular imaging has the potential to provide unique information that will guarantee their biosafety in humans and provide a rationale for the future development of new generations of reagents. In this context, non-invasive imaging of gene expression is an attractive prospect, allowing precise, spacio-temporal measurements of gene expression in longitudinal studies involving gene transfer vectors. With the emergence of cell therapies in regenerative medicine, it is also possible to track cells injected into subjects. In this context, the Na/I symporter (NIS) has been used in preclinical studies. Associated with a relevant radiotracer (123I-, 124I-, 99mTcO4-), NIS can be used to monitor gene transfer and the spread of selectively replicative viruses in tumours as well as in cells with a therapeutic potential. In addition to its imaging potential, NIS can be used as a therapeutic transgene through its ability to concentrate therapeutic doses of radionuclides in target cells. This dual property has applications in cancer treatment and could also be used to eradicate cells with therapeutic potential in the case of adverse events. Through experience acquired in preclinical studies, we can expect that non-invasive molecular imaging using NIS as a transgene will be pivotal for monitoring in vivo the exact distribution and pharmacodynamics of gene expression in a precise and quantitative way. This review highlights the applications of NIS in biotherapy, with a particular emphasis on image-guided radiotherapy, monitoring of gene and vector biodistribution and trafficking of stem cells. This article is part of a themed section on Imaging in Pharmacology. To view the editorial for this themed section visit http://dx.doi.org/10.1111/j.1476-5381.2010.00685.x PMID:19814733

Surgery in extensive vertebral hemangioma: case report, literature review and a new algorithm proposal.

PubMed

Tarantino, Roberto; Donnarumma, Pasquale; Nigro, Lorenzo; Delfini, Roberto

2015-07-01

Hemangiomas are benign dysplasias or vascular tumors consisting of vascular spaces lined with endothelium. Nowadays, radiotherapy for vertebral hemangiomas (VHs) is widely accepted as primary treatment for painful lesions. Nevertheless, the role of surgery is still unclear. The purpose of this study is to propose a novel algorithm of treatment about VHs. This is a case report of an extensive VH and a review of the literature. A case of vertebral fracture during radiotherapy at a total dose of 30 Gy given in 10 fractions (treatment time 2 weeks) using a linear accelerator at 15 MV high-energy photons for extensive VH is reported. Using PubMed database, a review of the literature is done. The authors have no study funding sources. The authors have no conflicting financial interests. In the literature, good results in terms of pain and neurological deficits are reported. No cases of vertebral fractures are described. However, there is no consensus regarding the treatment for VHs. Radiotherapy is widely utilized in VHs determining pain. Surgery for VHs determining neurological deficit is also widely accepted. Perhaps, regarding the width of the lesion, no indications are given. We consider it important to make an evaluation before initiating the treatment for the risk of pathologic vertebral fracture, since in radiotherapy, there is no convention regarding structural changes determined in VHs. We propose a new algorithm of treatment. We recommend radiotherapy only for small lesions in which vertebral stability is not concerned. Kyphoplasty can be proposed for asymptomatic patients in which VHs are small and in patients affected by VHs determining pain without spinal canal invasion in which the VH is small. In patients affected by pain without spinal canal invasion but in which the VH is wide or presented with spinal canal invasion and in patients affected by neurological deficits, we propose surgery.

MRI-Related Geometric Distortions in Stereotactic Radiotherapy Treatment Planning: Evaluation and Dosimetric Impact.

PubMed

Pappas, Eleftherios P; Alshanqity, Mukhtar; Moutsatsos, Argyris; Lababidi, Hani; Alsafi, Khalid; Georgiou, Konstantinos; Karaiskos, Pantelis; Georgiou, Evangelos

2017-12-01

In view of their superior soft tissue contrast compared to computed tomography, magnetic resonance images are commonly involved in stereotactic radiosurgery/radiotherapy applications for target delineation purposes. It is known, however, that magnetic resonance images are geometrically distorted, thus deteriorating dose delivery accuracy. The present work focuses on the assessment of geometric distortion inherent in magnetic resonance images used in stereotactic radiosurgery/radiotherapy treatment planning and attempts to quantitively evaluate the consequent impact on dose delivery. The geometric distortions for 3 clinical magnetic resonance protocols (at both 1.5 and 3.0 T) used for stereotactic radiosurgery/radiotherapy treatment planning were evaluated using a recently proposed phantom and methodology. Areas of increased distortion were identified at the edges of the imaged volume which was comparable to a brain scan. Although mean absolute distortion did not exceed 0.5 mm on any spatial axis, maximum detected control point disposition reached 2 mm. In an effort to establish what could be considered as acceptable geometric uncertainty, highly conformal plans were utilized to irradiate targets of different diameters (5-50 mm). The targets were mispositioned by 0.5 up to 3 mm, and dose-volume histograms and plan quality indices clinically used for plan evaluation and acceptance were derived and used to investigate the effect of geometrical uncertainty (distortion) on dose delivery accuracy and plan quality. The latter was found to be strongly dependent on target size. For targets less than 20 mm in diameter, a spatial disposition of the order of 1 mm could significantly affect (>5%) plan acceptance/quality indices. For targets with diameter greater than 2 cm, the corresponding disposition was found greater than 1.5 mm. Overall results of this work suggest that efficacy of stereotactic radiosurgery/radiotherapy applications could be compromised in case of very small targets lying distant from the scanner's isocenter (eg, the periphery of the brain).

Precision liquid level sensor

DOEpatents

Field, Michael E.; Sullivan, William H.

1985-01-01

A precision liquid level sensor utilizes a balanced R. F. bridge, each arm including an air dielectric line. Changes in liquid level along one air dielectric line imbalance the bridge and create a voltage which is directly measurable across the bridge.

Feasibility study of a lead(II) iodide-based dosimeter for quality assurance in therapeutic radiology

NASA Astrophysics Data System (ADS)

Heo, Y. J.; Kim, K. T.; Oh, K. M.; Lee, Y. K.; Ahn, K. J.; Cho, H. L.; Kim, J. Y.; Min, B. I.; Mun, C. W.; Park, S. K.

2017-09-01

The most widely used form of radiotherapy to treat tumors uses a linear accelerator, and the apparatus requires regular quality assurance (QA). QA for a linear accelerator demands accuracy throughout, from mock treatment and treatment planning, up to treatment itself. Therefore, verifying a radiation dose is essential to ensure that the radiation is being applied as planned. In current clinical practice, ionization chambers and diodes are used for QA. However, using conventional gaseous ionization chambers presents drawbacks such as complex analytical procedures, difficult measurement procedures, and slow response time. In this study, we discuss the potential of a lead(II) iodide (PbI2)-based radiation dosimeter for radiotherapy QA. PbI2 is a semiconductor material suited to measurements of X-rays and gamma rays, because of its excellent response properties to radiation signals. Our results show that the PbI2-based dosimeter offers outstanding linearity and reproducibility, as well as dose-independent characteristics. In addition, percentage depth dose (PDD) measurements indicate that the error at a fixed reference depth Dmax was 0.3%, very similar to the measurement results obtained using ionization chambers. Based on these results, we confirm that the PbI2-based dosimeter has all the properties required for radiotherapy: stable dose detection, dose linearity, and rapid response time. Based on the evidence of this experimental verification, we believe that the PbI2-based dosimeter could be used commercially in various fields for precise measurements of radiation doses in the human body and for measuring the dose required for stereotactic radiosurgery or localized radiosurgery.

Present and Future of Hadrontherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amaldi, Ugo; Department of Physics, University of Milano-Bicocca, Milan; Braccini, Saverio

2006-04-07

In the developed countries every 10 million inhabitants about 20'000 oncological patients are irradiated every year with high-energy photons (called X-rays by radiotherapists) produced by electron linacs. This is the so called 'conventional' radiotherapy. Hadrontherapy is a novel technique of radiotherapy which instead of X-rays employs beams of charged hadrons, protons and carbon ions in particular. Due to their physical and radiobiological properties, they allow to obtain a more conformal treatment than X-rays, sparing better the surrounding healthy tissues with a subsequent larger control rate. By now about 40,000 patients have been treated worldwide with protons and 15 hospital basedmore » centres are either running or under construction. Carbon ion beams deliver the dose as precisely as protons and are characterized by a larger biological effectiveness than X-rays and protons. They are therefore particularly suited to treat radio resistant tumours, as proven by the clinical studies performed on about 2300 patients in HIMAC (Chiba, Japan) and on about 250 patients at GSI (Darmstadt, Germany). A second Japanese hospital based centre is now running in Hyogo and two are under construction in Europe, in Heidelberg (Germany) and Pave (Italy). A large diffusion of hadrontherapy is foreseen in the near future but a much larger diffusion, possibly comparable with the one of electron linacs in conventional radiotherapy, will be achieved only if much compact and cheap accelerators and dose delivery systems will be conceived and constructed. In this framework, the acceleration of protons based on laser plasma techniques represents a very interesting and challenging possibility.« less

Automatic transperineal ultrasound probe positioning based on CT scan for image guided radiotherapy

NASA Astrophysics Data System (ADS)

Camps, S. M.; Verhaegen, F.; Paiva Fonesca, G.; de With, P. H. N.; Fontanarosa, D.

2017-03-01

Image interpretation is crucial during ultrasound image acquisition. A skilled operator is typically needed to verify if the correct anatomical structures are all visualized and with sufficient quality. The need for this operator is one of the major reasons why presently ultrasound is not widely used in radiotherapy workflows. To solve this issue, we introduce an algorithm that uses anatomical information derived from a CT scan to automatically provide the operator with a patient-specific ultrasound probe setup. The first application we investigated, for its relevance to radiotherapy, is 4D transperineal ultrasound image acquisition for prostate cancer patients. As initial test, the algorithm was applied on a CIRS multi-modality pelvic phantom. Probe setups were calculated in order to allow visualization of the prostate and adjacent edges of bladder and rectum, as clinically required. Five of the proposed setups were reproduced using a precision robotic arm and ultrasound volumes were acquired. A gel-filled probe cover was used to ensure proper acoustic coupling, while taking into account possible tilted positions of the probe with respect to the flat phantom surface. Visual inspection of the acquired volumes revealed that clinical requirements were fulfilled. Preliminary quantitative evaluation was also performed. The mean absolute distance (MAD) was calculated between actual anatomical structure positions and positions predicted by the CT-based algorithm. This resulted in a MAD of (2.8±0.4) mm for prostate, (2.5±0.6) mm for bladder and (2.8±0.6) mm for rectum. These results show that no significant systematic errors due to e.g. probe misplacement were introduced.

Precision medicine and precision therapeutics: hedgehog signaling pathway, basal cell carcinoma and beyond.

PubMed

Mohan, Shalini V; Chang, Anne Lynn S

2014-06-01

Precision medicine and precision therapeutics is currently in its infancy with tremendous potential to improve patient care by better identifying individuals at risk for skin cancer and predict tumor responses to treatment. This review focuses on the Hedgehog signaling pathway, its critical role in the pathogenesis of basal cell carcinoma, and the emergence of targeted treatments for advanced basal cell carcinoma. Opportunities to utilize precision medicine are outlined, such as molecular profiling to predict basal cell carcinoma response to targeted therapy and to inform therapeutic decisions.

Reproducible deep-inspiration breath-hold irradiation with forward intensity-modulated radiotherapy for left-sided breast cancer significantly reduces cardiac radiation exposure compared to inverse intensity-modulated radiotherapy.

PubMed

Bolukbasi, Yasemin; Saglam, Yucel; Selek, Ugur; Topkan, Erkan; Kataria, Anglina; Unal, Zeynep; Alpan, Vildan

2014-01-01

To investigate the objective utility of our clinical routine of reproducible deep-inspiration breath-hold irradiation for left-sided breast cancer patients on reducing cardiac exposure. Free-breathing and reproducible deep-inspiration breath-hold scans were evaluated for our 10 consecutive left-sided breast cancer patients treated with reproducible deep-inspiration breath-hold. The study was based on the adjuvant dose of 50 Gy in 25 fractions of 2 Gy/fraction. Both inverse and forward intensity-modulated radiotherapy plans were generated for each computed tomography dataset. Reproducible deep-inspiration breath-hold plans with forward intensity-modulated radiotherapy significantly spared the heart and left anterior descending artery compared to generated free-breathing plans based on mean doses - free-breathing vs reproducible deep-inspiration breath-hold, left ventricle (296.1 vs 94.5 cGy, P = 0.005), right ventricle (158.3 vs 59.2 cGy, P = 0.005), left anterior descending artery (171.1 vs 78.1 cGy, P = 0.005), and whole heart (173.9 vs 66 cGy, P = 0.005), heart V20 (2.2% vs 0%, P = 0.007) and heart V10 (4.2% vs 0.3%, P = 0.007) - whereas they revealed no additional burden on the ipsilateral lung. Reproducible deep-inspiration breath-hold and free-breathing plans with inverse intensity-modulated radiotherapy provided similar organ at risk sparing by reducing the mean doses to the left ventricle, left anterior descending artery, heart, V10-V20 of the heart and right ventricle. However, forward intensity-modulated radiotherapy showed significant reduction in doses to the left ventricle, left anterior descending artery, heart, right ventricle, and contralateral breast (mean dose, 248.9 to 12.3 cGy, P = 0.005). The mean doses for free-breathing vs reproducible deep-inspiration breath-hold of the proximal left anterior descending artery were 1.78 vs 1.08 Gy and of the distal left anterior descending artery were 8.11 vs 3.89 Gy, whereas mean distances to the 50 Gy isodose line of the proximal left anterior descending artery were 6.6 vs 3.3 cm and of the distal left anterior descending artery were 7.4 vs 4.1 cm, with forward intensity-modulated radiotherapy. Overall reduction in mean doses to proximal and distal left anterior descending artery with deep-inspiration breath-hold irradiation was 39% (P = 0.02) and 52% (P = 0.002), respectively. We found a significant reduction of radiation exposure to the contralateral breast, left and right ventricles, as well as of proximal and especially distal left anterior descending artery with the deep-inspiration breath-hold technique with forward intensity-modulated radiotherapy planning.

Chlorotoxin-Conjugated Multifunctional Dendrimers Labeled with Radionuclide 131I for Single Photon Emission Computed Tomography Imaging and Radiotherapy of Gliomas.

PubMed

Zhao, Lingzhou; Zhu, Jingyi; Cheng, Yongjun; Xiong, Zhijuan; Tang, Yueqin; Guo, Lilei; Shi, Xiangyang; Zhao, Jinhua

2015-09-09

Chlorotoxin-conjugated multifunctional dendrimers labeled with radionuclide 131I were synthesized and utilized for targeted single photon emission computed tomography (SPECT) imaging and radiotherapy of cancer. In this study, generation five amine-terminated poly(amidoamine) dendrimers were used as a platform to be sequentially conjugated with polyethylene glycol (PEG), targeting agent chlorotoxin (CTX), and 3-(4'-hydroxyphenyl)propionic acid-OSu (HPAO). This was followed by acetylation of the remaining dendrimer terminal amines and radiolabeling with 131I to form the targeted theranostic dendrimeric nanoplatform. We show that the dendrimer platform possessing approximately 7.7 CTX and 21.1 HPAO moieties on each dendrimer displays excellent cytocompatibility in a given concentration range (0-20 μM) and can specifically target cancer cells overexpressing matrix metallopeptidase 2 (MMP2) due to the attached CTX. With the attached HPAO moiety having the phenol group, the dendrimer platform can be effectively labeled with radioactive 131I with good stability and high radiochemical purity. Importantly, the 131I labeling renders the dendrimer platform with an ability to be used for targeted SPECT imaging and radiotherapy of an MMP2-overexpressing glioma model in vivo. The developed radiolabeled multifunctional dendrimeric nanoplatform may hold great promise to be used for targeted theranostics of human gliomas.

Patient safety in external beam radiotherapy, results of the ACCIRAD project: Current status of proactive risk assessment, reactive analysis of events, and reporting and learning systems in Europe.

PubMed

Malicki, Julian; Bly, Ritva; Bulot, Mireille; Godet, Jean-Luc; Jahnen, Andreas; Krengli, Marco; Maingon, Philippe; Prieto Martin, Carlos; Przybylska, Kamila; Skrobała, Agnieszka; Valero, Marc; Jarvinen, Hannu

2017-04-01

To describe the current status of implementation of European directives for risk management in radiotherapy and to assess variability in risk management in the following areas: 1) in-country regulatory framework; 2) proactive risk assessment; (3) reactive analysis of events; and (4) reporting and learning systems. The original data were collected as part of the ACCIRAD project through two online surveys. Risk assessment criteria are closely associated with quality assurance programs. Only 9/32 responding countries (28%) with national regulations reported clear "requirements" for proactive risk assessment and/or reactive risk analysis, with wide variability in assessment methods. Reporting of adverse error events is mandatory in most (70%) but not all surveyed countries. Most European countries have taken steps to implement European directives designed to reduce the probability and magnitude of accidents in radiotherapy. Variability between countries is substantial in terms of legal frameworks, tools used to conduct proactive risk assessment and reactive analysis of events, and in the reporting and learning systems utilized. These findings underscore the need for greater harmonisation in common terminology, classification and reporting practices across Europe to improve patient safety and to enable more reliable inter-country comparisons. Copyright © 2017 Elsevier B.V. All rights reserved.

Paradigm shift of therapeutic management of brain metastases in EGFR-mutant non-small cell lung cancer in the era of targeted therapy.

PubMed

Sekine, Akimasa; Satoh, Hiroaki

2017-07-01

Non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations commonly present brain metastases (BM) at the time of NSCLC diagnosis or during the clinical course. Conventionally, the prognosis of BM has been extremely poor, but the advent of EGFR-tyrosine kinase inhibitors (TKIs) has drastically improved the prognosis in these patients. Despite the presence of the blood-brain barrier, EGFR-TKIs have dramatic therapeutic effects on both BM and extracranial disease. In addition, recent systemic chemotherapies reportedly play a role in controlling BM. These treatment modalities can potentially replace whole brain radiotherapy (WBRT) to prevent or delay neurocognitive decline. Therefore, how to utilize these treatments is one issue. The other issue is what kind of treatment is best for recurrence after TKI therapy. Recent reports have shown a positive effect of a combination therapy of EGFR-TKI and radiotherapy on BM. Although neurocognitive decline is underscored when WBRT is considered, a survival benefit from WBRT has been proven especially in the potential long survivors with good prognostic index, especially disease-specific graded prognostic index (DS-GPA). In this review, treatment strategy including chemotherapeutic agents and radiotherapy is discussed in terms of risk-benefit balance in conjunction with DS-GPA.

Data-driven gating in PET: Influence of respiratory signal noise on motion resolution.

PubMed

Büther, Florian; Ernst, Iris; Frohwein, Lynn Johann; Pouw, Joost; Schäfers, Klaus Peter; Stegger, Lars

2018-05-21

Data-driven gating (DDG) approaches for positron emission tomography (PET) are interesting alternatives to conventional hardware-based gating methods. In DDG, the measured PET data themselves are utilized to calculate a respiratory signal, that is, subsequently used for gating purposes. The success of gating is then highly dependent on the statistical quality of the PET data. In this study, we investigate how this quality determines signal noise and thus motion resolution in clinical PET scans using a center-of-mass-based (COM) DDG approach, specifically with regard to motion management of target structures in future radiotherapy planning applications. PET list mode datasets acquired in one bed position of 19 different radiotherapy patients undergoing pretreatment [ 18 F]FDG PET/CT or [ 18 F]FDG PET/MRI were included into this retrospective study. All scans were performed over a region with organs (myocardium, kidneys) or tumor lesions of high tracer uptake and under free breathing. Aside from the original list mode data, datasets with progressively decreasing PET statistics were generated. From these, COM DDG signals were derived for subsequent amplitude-based gating of the original list mode file. The apparent respiratory shift d from end-expiration to end-inspiration was determined from the gated images and expressed as a function of signal-to-noise ratio SNR of the determined gating signals. This relation was tested against additional 25 [ 18 F]FDG PET/MRI list mode datasets where high-precision MR navigator-like respiratory signals were available as reference signal for respiratory gating of PET data, and data from a dedicated thorax phantom scan. All original 19 high-quality list mode datasets demonstrated the same behavior in terms of motion resolution when reducing the amount of list mode events for DDG signal generation. Ratios and directions of respiratory shifts between end-respiratory gates and the respective nongated image were constant over all statistic levels. Motion resolution d/d max could be modeled as d/dmax=1-e-1.52(SNR-1)0.52, with d max as the actual respiratory shift. Determining d max from d and SNR in the 25 test datasets and the phantom scan demonstrated no significant differences to the MR navigator-derived shift values and the predefined shift, respectively. The SNR can serve as a general metric to assess the success of COM-based DDG, even in different scanners and patients. The derived formula for motion resolution can be used to estimate the actual motion extent reasonably well in cases of limited PET raw data statistics. This may be of interest for individualized radiotherapy treatment planning procedures of target structures subjected to respiratory motion. © 2018 American Association of Physicists in Medicine.

An imaging informatics-based system utilizing DICOM objects for treating pain in spinal cord injury patients utilizing proton beam radiotherapy

NASA Astrophysics Data System (ADS)

Verma, Sneha K.; Liu, Brent J.; Chun, Sophia; Gridley, Daila S.

2014-03-01

Many US combat personnel have sustained nervous tissue trauma during service, which often causes Neuropathic pain as a side effect and is difficult to manage. However in select patients, synapse lesioning can provide significant pain control. Our goal is to determine the effectiveness of using Proton Beam radiotherapy for treating spinal cord injury (SCI) related neuropathic pain as an alternative to invasive surgical lesioning. The project is a joint collaboration of USC, Spinal Cord Institute VA Healthcare System, Long Beach, and Loma Linda University. This is first system of its kind that supports integration and standardization of imaging informatics data in DICOM format; clinical evaluation forms outcomes data and treatment planning data from the Treatment planning station (TPS) utilized to administer the proton therapy in DICOM-RT format. It also supports evaluation of SCI subjects for recruitment into the clinical study, which includes the development, and integration of digital forms and tools for automatic evaluation and classification of SCI pain. Last year, we presented the concept for the patient recruitment module based on the principle of Bayesian decision theory. This year we are presenting the fully developed patient recruitment module and its integration to other modules. In addition, the DICOM module for integrating DICOM and DICOM-RT-ION data is also developed and integrated. This allows researchers to upload animal/patient study data into the system. The patient recruitment module has been tested using 25 retrospective patient data and DICOM data module is tested using 5 sets of animal data.

Influence of local topography on precision irrigation management

USDA-ARS?s Scientific Manuscript database

Precision irrigation management is currently accomplished using spatial information about soil properties through soil series maps or electrical conductivity (EC measurements. Crop yield, however, is consistently influenced by local topography, both in rain-fed and irrigated environments. Utilizing ...

Precision liquid level sensor

DOEpatents

Field, M.E.; Sullivan, W.H.

1985-01-29

A precision liquid level sensor utilizes a balanced R. F. bridge, each arm including an air dielectric line. Changes in liquid level along one air dielectric line imbalance the bridge and create a voltage which is directly measurable across the bridge. 2 figs.

Health economics of targeted intraoperative radiotherapy (TARGIT-IORT) for early breast cancer: a cost-effectiveness analysis in the United Kingdom.

PubMed

Vaidya, Anil; Vaidya, Param; Both, Brigitte; Brew-Graves, Chris; Bulsara, Max; Vaidya, Jayant S

2017-08-17

The clinical effectiveness of targeted intraoperative radiotherapy (TARGIT-IORT) has been confirmed in the randomised TARGIT-A (targeted intraoperative radiotherapy-alone) trial to be similar to a several weeks' course of whole-breast external-beam radiation therapy (EBRT) in patients with early breast cancer. This study aims to determine the cost-effectiveness of TARGIT-IORT to inform policy decisions about its wider implementation. TARGIT-A randomised clinical trial (ISRCTN34086741) which compared TARGIT with traditional EBRT and found similar breast cancer control, particularly when TARGIT was given simultaneously with lumpectomy. Cost-utility analysis using decision analytic modelling by a Markov model. A cost-effectiveness Markov model was developed using TreeAge Pro V.2015. The decision analytic model compared two strategies of radiotherapy for breast cancer in a hypothetical cohort of patients with early breast cancer based on the published health state transition probability data from the TARGIT-A trial. Analysis was performed for UK setting and National Health Service (NHS) healthcare payer's perspective using NHS cost data and treatment outcomes were simulated for both strategies for a time horizon of 10 years. Model health state utilities were drawn from the published literature. Future costs and effects were discounted at the rate of 3.5%. To address uncertainty, one-way and probabilistic sensitivity analyses were performed. Quality-adjusted life-years (QALYs). In the base case analysis, TARGIT-IORT was a highly cost-effective strategy yielding health gain at a lower cost than its comparator EBRT. Discounted TARGIT-IORT and EBRT costs for the time horizon of 10 years were £12 455 and £13 280, respectively. TARGIT-IORT gained 0.18 incremental QALY as the discounted QALYs gained by TARGIT-IORT were 8.15 and by EBRT were 7.97 showing TARGIT-IORT as a dominant strategy over EBRT. Model outputs were robust to one-way and probabilistic sensitivity analyses. TARGIT-IORT is a dominant strategy over EBRT, being less costly and producing higher QALY gain. ISRCTN34086741; post results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Patient positioning using artificial intelligence neural networks, trained magnetic field sensors and magnetic implants.

PubMed

Lennernäs, B; Edgren, M; Nilsson, S

1999-01-01

The purpose of this study was to evaluate the precision of a sensor and to ascertain the maximum distance between the sensor and the magnet, in a magnetic positioning system for external beam radiotherapy using a trained artificial intelligence neural network for position determination. Magnetic positioning for radiotherapy, previously described by Lennernäs and Nilsson, is a functional technique, but it is time consuming. The sensors are large and the distance between the sensor and the magnetic implant is limited to short distances. This paper presents a new technique for positioning, using an artificial intelligence neural network, which was trained to position the magnetic implant with at least 0.5 mm resolution in X and Y dimensions. The possibility of using the system for determination in the Z dimension, that is the distance between the magnet and the sensor, was also investigated. After training, this system positioned the magnet with a mean error of maximum 0.15 mm in all dimensions and up to 13 mm from the sensor. Of 400 test positions, 8 determinations had an error larger than 0.5 mm, maximum 0.55 mm. A position was determined in approximately 0.01 s.

Role of fluorine-18 fluorodeoxyglucose PET/CT in head and neck oncology: the point of view of the radiation oncologist

PubMed Central

Navarro, Arturo; del Hoyo, Olga; Gomez-Iturriaga, Alfonso; Alongi, Filippo; Medina, Jose A; Elicin, Olgun; Skanjeti, Andrea; Giammarile, Francesco; Bilbao, Pedro; Casquero, Francisco; de Bari, Berardino; Dal Pra, Alan

2016-01-01

Squamous cell carcinoma is the most common malignant tumour of the head and neck. The initial TNM staging, the evaluation of the tumour response during treatment, and the long-term surveillance are crucial moments in the approach to head and neck squamous cell carcinoma (HNSCC). Thus, at each of these moments, the choice of the best diagnostic tool providing the more precise and larger information is crucial. Positron emission tomography with fluorine-18 fludeoxyglucose integrated with CT (18F-FDG-PET/CT) rapidly gained clinical acceptance, and it has become an important imaging tool in routine clinical oncology. However, controversial data are currently available, for example, on the role of 18F-FDG-PET/CT imaging during radiotherapy planning, the prognostic value or its real clinical impact on treatment decisions. In this article, the role of 18F-FDG-PET/CT imaging in HNSCC during pre-treatment staging, radiotherapy planning, treatment response assessment, prognosis and follow-up is reviewed focusing on current evidence and controversial issues. A proposal on how to integrate 18F-FDG-PET/CT in daily clinical practice is also described. PMID:27416996

Nuclear imaging and radiation therapy in canine and feline thyroid disease.

PubMed

Feeney, Daniel A; Anderson, Kari L

2007-07-01

The indications, techniques, and expectations for radionuclide diagnostic studies on canine and feline thyroid glands are presented. In addition, the considerations surrounding radioiodine or external beam radiotherapy for benign and malignant thyroid disease are reviewed. The intent of this article is to familiarize primary care veterinarians with the utility of and outcome of the ionizing radiation-based diagnostic and therapeutic techniques for assessing and treating canine and feline thyroid disease.

Radiofrequency Guide Wire Recanalization of Venous Occlusions in Patients with Malignant Superior Vena Cava Syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Robert M.; David, Elizabeth; Pugash, Robyn A.

Fibrotic central venous occlusions in patients with thoracic malignancy and prior radiotherapy can be impassable with standard catheters and wires, including the trailing or stiff end of a hydrophilic wire. We report two patients with superior vena cava syndrome in whom we successfully utilized a radiofrequency guide wire (PowerWire, Baylis Medical, Montreal, Quebec, Canada) to perforate through the occlusion and recanalize the occluded segment to alleviate symptoms.

Effect of x-radiation to brain on cerebral glucose utilization in the rat.

PubMed

D'Aquino, S; Cicciarello, R; D'Avella, D; Mesiti, M; Albiero, F; Princi, P; Gagliardi, M E; Russi, E; D'Aquino, A

1990-01-01

We assessed, by means of the [14C]-2-deoxy-D-glucose autoradiography method, the effect of whole-brain x-radiation on local cerebral glucose utilization in the rat brain. Animals were exposed to conventional fractionation (200 +/- cGy/day given 5 days a week) to a total dose of 4000 cGy. Metabolic experiments were made 2 weeks after completion of the radiation exposure. In comparison with control and sham-irradiated animals, cerebral metabolic activity was diffusely decreased following irradiation. Statistically significant decreases in metabolic activity were observed in 13 of 27 brain regions studied. In general, brain areas with the highest basal metabolic rates showed the greatest percentage drop of glucose utilization. Post-irradiation metabolic alterations possibly provide an explanation for the syndrome of early delayed deterioration observed in humans after whole-brain radiotherapy.

Impact of dose escalation and adaptive radiotherapy for cervical cancers on tumour shrinkage—a modelling study

NASA Astrophysics Data System (ADS)

Røthe Arnesen, Marius; Paulsen Hellebust, Taran; Malinen, Eirik

2017-03-01

Tumour shrinkage occurs during fractionated radiotherapy and is regulated by radiation induced cellular damage, repopulation of viable cells and clearance of dead cells. In some cases additional tumour shrinkage during external beam therapy may be beneficial, particularly for locally advanced cervical cancer where a small tumour volume may simplify and improve brachytherapy. In the current work, a mathematical tumour model is utilized to investigate how local dose escalation affects tumour shrinkage, focusing on implications for brachytherapy. The iterative two-compartment model is based upon linear-quadratic radiation response, a doubling time for viable cells and a half-time for clearance of dead cells. The model was individually fitted to clinical tumour volume data from fractionated radiotherapy of 25 cervical cancer patients. Three different fractionation patterns for dose escalation, all with an additional dose of 12.2 Gy, were simulated and compared to standard fractionation in terms of tumour shrinkage. An adaptive strategy where dose escalation was initiated after one week of treatment was also considered. For 22 out of 25 patients, a good model fit was achieved to the observed tumour shrinkage. A large degree of inter-patient variation was seen in predicted volume reduction following dose escalation. For the 10 best responding patients, a mean tumour volume reduction of 34  ±  3% (relative to standard treatment) was estimated at the time of brachytherapy. Timing of initiating dose escalation had a larger impact than the number of fractions applied. In conclusion, the model was found useful in evaluating the impact from dose escalation on tumour shrinkage. The results indicate that dose escalation could be conducted from the start of external beam radiotherapy in order to obtain additional tumour shrinkage before brachytherapy.

Breast Radiotherapy with Mixed Energy Photons; a Model for Optimal Beam Weighting.

PubMed

Birgani, Mohammadjavad Tahmasebi; Fatahiasl, Jafar; Hosseini, Seyed Mohammad; Bagheri, Ali; Behrooz, Mohammad Ali; Zabiehzadeh, Mansour; Meskani, Reza; Gomari, Maryam Talaei

2015-01-01

Utilization of high energy photons (>10 MV) with an optimal weight using a mixed energy technique is a practical way to generate a homogenous dose distribution while maintaining adequate target coverage in intact breast radiotherapy. This study represents a model for estimation of this optimal weight for day to day clinical usage. For this purpose, treatment planning computed tomography scans of thirty-three consecutive early stage breast cancer patients following breast conservation surgery were analyzed. After delineation of the breast clinical target volume (CTV) and placing opposed wedge paired isocenteric tangential portals, dosimeteric calculations were conducted and dose volume histograms (DVHs) were generated, first with pure 6 MV photons and then these calculations were repeated ten times with incorporating 18 MV photons (ten percent increase in weight per step) in each individual patient. For each calculation two indexes including maximum dose in the breast CTV (Dmax) and the volume of CTV which covered with 95% Isodose line (VCTV, 95%IDL) were measured according to the DVH data and then normalized values were plotted in a graph. The optimal weight of 18 MV photons was defined as the intersection point of Dmax and VCTV, 95%IDL graphs. For creating a model to predict this optimal weight multiple linear regression analysis was used based on some of the breast and tangential field parameters. The best fitting model for prediction of 18 MV photons optimal weight in breast radiotherapy using mixed energy technique, incorporated chest wall separation plus central lung distance (Adjusted R2=0.776). In conclusion, this study represents a model for the estimation of optimal beam weighting in breast radiotherapy using mixed photon energy technique for routine day to day clinical usage.

Assessment of Solid Cancer Treatment Feasibility in Older Patients: A Prospective Cohort Study

PubMed Central

Laurent, Marie; Paillaud, Elena; Tournigand, Christophe; Caillet, Philippe; Le Thuaut, Aurélie; Lagrange, Jean-Léon; Beauchet, Olivier; Vincent, Hélène; Carvahlo-Verlinde, Muriel; Culine, Stéphane; Bastuji-Garin, Sylvie

2014-01-01

Purpose. To assess solid cancer treatment feasibility in older patients Methods. Between 2007 and 2010, 385 consecutive elderly patients (mean age: 78.9 ± 5.4 years; 47.8% males) with solid malignancies referred to two geriatric oncology clinics were included prospectively. We recorded feasibility of first-line chemotherapy (planned number of cycles in patients without metastases and three to six cycles depending on tumor site in patients with metastases), surgery (patient alive 30 days after successfully performed planned surgical procedure), radiotherapy (planned dose delivered), and hormonal therapy (planned drug dose given), and we recorded overall 1-year survival. Results. Main tumor sites were colorectal (28.6%), breast (23.1%), and prostate (10.9%), and 47% of patients had metastases. Planned cancer treatment was feasible in 65.7% of patients with metastases; this proportion was 59.0% for chemotherapy, 82.6% for surgery, 100% for radiotherapy, and 85.2% for hormonal therapy. In the group without metastases, feasibility proportions were 86.8% overall, 72.4% for chemotherapy, 95.7% for surgery, 96.4% for radiotherapy, and 97.9% for hormonal therapy. Factors independently associated with chemotherapy feasibility were good functional status defined as Eastern Cooperative Oncology Group performance status <2 (p < .0001) or activities of daily living >5 (p = .01), normal mobility defined as no difficulty walking (p = .01) or no fall risk (p = .007), and higher creatinine clearance (p = .04). Conclusion. Feasibility rates were considerably lower for chemotherapy than for surgery, radiotherapy, and hormonal therapy. Therefore, utilization of limited geriatric oncology resources may be optimized by preferential referral of elderly cancer patients initially considered for chemotherapy to geriatric oncology clinics. PMID:24569945

The clinical application of the 100mL water swallow test in head and neck cancer.

PubMed

Patterson, Joanne M; Hildreth, Anthony; McColl, Elaine; Carding, Paul N; Hamilton, David; Wilson, Janet A

2011-03-01

Water swallow tests have been used as to screen patients with neurological dysphagia who are at risk of aspiration. This study examines the clinical utility of the 100mL water swallow test (WST) in head and neck cancer, by measuring its sensitivity and specificity for identifying aspiration and for monitoring swallow performance up to one year following (chemo)radiotherapy. Patients referred for (chemo)radiotherapy were assessed on the WST (n=173) pre-treatment and 3, 6 and 12months post-treatment. Patients failed the test if they coughed or had a wet voice quality post swallow or were unable to finish the task. A Flexible Endoscopic Evaluation of Swallowing was conducted at the same time points, to test for the presence of aspiration. The WST was timed and the number of swallows required was recorded. Sensitivity of the WST for predicting aspiration was >67%, specificity >46%. There was marked deterioration from pre- to 3months post-treatment for the time taken to drink 100mL (p=0.005), but this improved over the first year (p=0.001). Disease characteristics, patient demographics, radiotherapy dose, or treatment volume were not predictors of this improvement. The 100mL WST is a quick and simple assessment for identifying patients with aspiration, post (chemo)radiotherapy. This test is a useful adjunct to a clinical examination, helping to highlight patients who require an instrumental assessment such as videofluoroscopy. Furthermore, quantitative measures can be derived from this test, which can be used as a measure of swallow performance over time. Copyright © 2010 Elsevier Ltd. All rights reserved.

Evidence for the use PET for radiation therapy planning in patients with cervical cancer: a systematic review.

PubMed

Salem, A; Salem, A F; Al-Ibraheem, A; Lataifeh, I; Almousa, A; Jaradat, I

2011-01-01

In recent years, the role of positron emission tomography (PET) in the staging and management of gynecological cancers has been increasing. The aim of this study was to systematically review the role of PET in radiotherapy planning and brachytherapy treatment optimization in patients with cervical cancer. Systematic literature review. Systematic review of relevant literature addressing the utilization of PET and/or PET-computed tomography (CT) in external-beam radiotherapy planning and brachytherapy treatment optimization. We performed an extensive PubMed database search on 20 April 2011. Nineteen studies, including 759 patients, formed the basis of this systematic review. PET/ PET-CT is the most sensitive imaging modality for detecting nodal metastases in patients with cervical cancer and has been shown to impact external-beam radiotherapy planning by modifying the treatment field and customizing the radiation dose. This particularly applies to detection of previously uncovered para-aortic and inguinal nodal metastases. Furthermore, PET/ PET-CT guided intensity-modulated radiation therapy (IMRT) allows delivery of higher doses of radiation to the primary tumor, if brachytherapy is unsuitable, and to grossly involved nodal disease while minimizing treatment-related toxicity. PET/ PET-CT based brachytherapy optimization allows improved tumor-volume dose distribution and detailed 3D dosimetric evaluation of risk organs. Sequential PET/ PET-CT imaging performed during the course of brachytherapy form the basis of “adaptive” brachytherapy in cervical cancer. This review demonstrates the effectiveness of pretreatment PET/ PET-CT in cervical cancer patients treated by radiotherapy. Further prospective studies are required to define the group of patients who would benefit the most from this procedure.

Palliative radiotherapy in addition to self-expanding metal stent for improving dysphagia and survival in advanced oesophageal cancer (ROCS: Radiotherapy after Oesophageal Cancer Stenting): study protocol for a randomized controlled trial.

PubMed

Adamson, Douglas; Blazeby, Jane; Nelson, Annmarie; Hurt, Chris; Nixon, Lisette; Fitzgibbon, Jim; Crosby, Tom; Staffurth, John; Evans, Mim; Kelly, Noreen Hopewell; Cohen, David; Griffiths, Gareth; Byrne, Anthony

2014-10-22

The single most distressing symptom for patients with advanced esophageal cancer is dysphagia. Amongst the more effective treatments for relief of dysphagia is insertion of a self-expanding metal stent (SEMS). It is possible that the addition of a palliative dose of external beam radiotherapy may prolong the relief of dysphagia and provide additional survival benefit. The ROCS trial will assess the effect of adding palliative radiotherapy after esophageal stent insertion. The study is a randomized multicenter phase III trial, with an internal pilot phase, comparing stent alone versus stent plus palliative radiotherapy in patients with incurable esophageal cancer. Eligible participants are those with advanced esophageal cancer who are in need of stent insertion for primary management of dysphagia. Radiotherapy will be administered as 20 Gray (Gy) in five fractions over one week or 30 Gy in 10 fractions over two weeks, within four weeks of stent insertion. The internal pilot will assess rates and methods of recruitment; pre-agreed criteria will determine progression to the main trial. In total, 496 patients will be randomized in a 1:1 ratio with follow up until death. The primary outcome is time to progression of patient-reported dysphagia. Secondary outcomes include survival, toxicity, health resource utilization, and quality of life. An embedded qualitative study will explore the feasibility of patient recruitment by examining patients' motivations for involvement and their experiences of consent and recruitment, including reasons for not consenting. It will also explore patients' experiences of each trial arm. The ROCS study will be a challenging trial studying palliation in patients with a poor prognosis. The internal pilot design will optimize methods for recruitment and data collection to ensure that the main trial is completed on time. As a pragmatic trial, study strengths include collection of all follow-up data in the usual place of care, and a focus on patient-reported, rather than disease-orientated, outcomes. Exploration of patient experience and health economic analyses will be integral to the assessment of benefit for patients and the NHS. The trial was registered with Current Controlled Trials (registration number: ISRCTN12376468) on 10 July 2012.

CPU time optimization and precise adjustment of the Geant4 physics parameters for a VARIAN 2100 C/D gamma radiotherapy linear accelerator simulation using GAMOS.

PubMed

Arce, Pedro; Lagares, Juan Ignacio

2018-01-25

We have verified the GAMOS/Geant4 simulation model of a 6 MV VARIAN Clinac 2100 C/D linear accelerator by the procedure of adjusting the initial beam parameters to fit the percentage depth dose and cross-profile dose experimental data at different depths in a water phantom. Thanks to the use of a wide range of field sizes, from 2  ×  2 cm 2 to 40  ×  40 cm 2 , a small phantom voxel size and high statistics, fine precision in the determination of the beam parameters has been achieved. This precision has allowed us to make a thorough study of the different physics models and parameters that Geant4 offers. The three Geant4 electromagnetic physics sets of models, i.e. Standard, Livermore and Penelope, have been compared to the experiment, testing the four different models of angular bremsstrahlung distributions as well as the three available multiple-scattering models, and optimizing the most relevant Geant4 electromagnetic physics parameters. Before the fitting, a comprehensive CPU time optimization has been done, using several of the Geant4 efficiency improvement techniques plus a few more developed in GAMOS.

Gas Chromatic Mass Spectrometer

NASA Technical Reports Server (NTRS)

Wey, Chowen

1995-01-01

Gas chromatograph/mass spectrometer (GC/MS) used to measure and identify combustion species present in trace concentration. Advanced extractive diagnostic method measures to parts per billion (PPB), as well as differentiates between different types of hydrocarbons. Applicable for petrochemical, waste incinerator, diesel transporation, and electric utility companies in accurately monitoring types of hydrocarbon emissions generated by fuel combustion, in order to meet stricter environmental requirements. Other potential applications include manufacturing processes requiring precise detection of toxic gaseous chemicals, biomedical applications requiring precise identification of accumulative gaseous species, and gas utility operations requiring high-sensitivity leak detection.

(abstract) Precision Time and Frequency Transfer Utilizing SONET OC-3

NASA Technical Reports Server (NTRS)

Stein, Sam; Calhoun, Malcom; Kuhnle, Paul; Sydnor, Richard; Gifford, Al

1996-01-01

An innovative method of distributing precise time and reference frequency to users located several kilometers from a frequency standard and master clock has been developed by the Timing Solutions Corporation of Boulder, CO. The Optical Two-Way Time Transfer System (OTWTTS) utilizes a commercial SONET OC-3 facility interface to physically connect a master unit to multiple slave units at remote locations. Optical fiber is a viable alternative to standard copper cable and microwave transmission. This paper discusses measurements of frequency and timing stability over the OTWTTS.

Photo-thermal nanosystems for diseased cell treatment

NASA Astrophysics Data System (ADS)

Raeesi, Vahid

The prevalence of cancer and infectious disease demands for development of more effective treatment technologies. Current standard chemo- and radiotherapy for cancer offer only relative therapeutic efficacy at the cost of significant side-effects. On the other hand, resistance of microbes to current antibiotics has raised serious concern in public health sectors such as hospitals. Thermal therapy is an alternative technique that employs high temperatures to treat diseased cells via direct and indirect heat effects. Owing to its nature, this technique can offer enhanced therapeutic efficacy in local diseased regions via either mono- or combinatorial platforms and very minimal side-effects. However, existing bulk heating systems are limited in providing selective and controlled temperature rise in the desired region at tissue/cellular scales. This compromises the therapeutic efficacy of the treatment and increases the risk of off-target heating in healthy tissues. In this thesis, we propose the use of heat-generating nanoparticles to precisely target heat into small regions and study how they can be applied in cancer and bacteria treatment. Our model nanoparticle system generates heat by light stimulation. Different nanosystems based on this particle are developed and their thermal effects on therapeutic distribution are explored at tumor tissue and cellular scales. In addition, the thermal effect of these nanoparticles is utilized to overcome microbial resistance. By mechanistic understanding of nanoparticle thermal effects at different length scales, this research helps to rationalize proper design and development of heat- generating nanomedicine for cancer and microbial treatments.

The effect of Amifostine prophylaxis on bone densitometry, biomechanical strength and union in mandibular pathologic fracture repair.

PubMed

Tchanque-Fossuo, Catherine N; Donneys, Alexis; Sarhaddi, Deniz; Poushanchi, Behdod; Deshpande, Sagar S; Weiss, Daniela M; Buchman, Steven R

2013-11-01

Pathologic fractures (Fx) of the mandibles are severely debilitating consequences of radiation (XRT) in the treatment of craniofacial malignancy. We have previously demonstrated Amifostine's effect (AMF) in the remediation of radiation-induced cellular damage. We posit that AMF prophylaxis will preserve bone strength and drastically reverse radiotherapy-induced non-union in a murine mandibular model of pathologic fracture repair. Twenty-nine rats were randomized into 3 groups: Fx, XRT/Fx, and AMF/XRT/Fx. A fractionated human equivalent dose of radiation was delivered to the left hemimandibles of XRT/Fx and AMF/XRT/Fx. AMF/XRT/Fx was pre-treated with AMF. All groups underwent left mandibular osteotomy with external fixation and setting of a 2.1mm fracture gap post-operatively. Utilizing micro-computed tomography and biomechanical testing, the healed fracture was evaluated for strength. All radiomorphometrics and biomechanical properties were significantly diminished in XRT/Fx compared to both Fx and AMF/XRT/Fx. No difference was demonstrated between Fx and AMF/XRT/Fx in both outcomes. Our investigation establishes the significant and substantial capability of AMF prophylaxis to preserve and enhance bone union, quality and strength in the setting of human equivalent radiotherapy. Such novel discoveries establish the true potential to utilize pharmacotherapy to prevent and improve the treatment outcomes of radiation-induced late pathologic fractures. © 2013.

Amifostine Prophylaxis on Bone Densitometry, Biomechanical Strength and Union in Mandibular Pathologic Fracture Repair

PubMed Central

Tchanque-Fossuo, Catherine N.; Donneys, Alexis; Sarhaddi, Deniz; Poushanchi, Behdod; Deshpande, Sagar S.; Weiss, Daniela M.

2013-01-01

Background Pathologic fractures (Fx) of the mandibles are severely debilitating consequences of radiation (XRT) in the treatment of craniofacial malignancy. We have previously demonstrated Amifostine’s effect (AMF) in the remediation of radiation-induced cellular damage. We posit that AMF prophylaxis will preserve bone strength and drastically reverse radiotherapy-induced non-union in a murine mandibular model of pathologic fracture repair. Materials and Methods Twenty-nine rats were randomized into 3 groups: Fx, XRT/Fx, and AMF/XRT/Fx. A fractionated human equivalent dose of radiation was delivered to the left hemimandibles of XRT/Fx and AMF/XRT/Fx. AMF/XRT/Fx was pre-treated with AMF. All groups underwent left mandibular osteotomy with external fixation and setting of a 2.1mm fracture gap post-operatively. Utilizing micro-computed tomography and biomechanical testing, the healed fracture was evaluated for strength. Results All radiomorphometrics and biomechanical properties were significantly diminished in XRT/Fx compared to both Fx and AMF/XRT/Fx. No difference was demonstrated between Fx and AMF/XRT/Fx in both outcomes. Conclusion Our investigation establishes the significant and substantial capability of AMF prophylaxis to preserve and enhance bone union, quality and strength in the setting of human equivalent radiotherapy. Such novel discoveries establish the true potential to utilize pharmacotherapy to prevent and improve the treatment outcomes of radiation-induced late pathologic fractures. PMID:23860272

Esophageal cancer: outcomes of surgery, neoadjuvant chemotherapy, and three-dimension conformal radiotherapy.

PubMed

Fréchette, Eric; Buck, David A; Kaplan, Brian J; Chung, Theodore D; Shaw, James E; Kachnic, Lisa A; Neifeld, James P

2004-08-01

Neoadjuvant chemotherapy and radiation are being utilized with increasing frequency in the multimodal treatment of esophageal cancer, although their effects on morbidity, mortality, and survival remain unclear. The objective of this study was to determine the outcome of multimodal treatment in patients with localized esophageal cancer treated at a single institution. Between 1995 and 2002, 118 patients underwent treatment for localized esophageal cancer, utilizing surgery alone, chemoradiation alone, or surgery following neoadjuvant chemoradiation. There was no statistically significant difference in morbidity, mortality, or length of stay between the patients who received multimodal therapy when compared to surgery alone. A surgical resection after down-staging was possible in 9 out of 28 patients (32%) with a clinically non-resectable tumor (T4 or M1a). Forty-seven percent of the patients who received neoadjuvant therapy had a complete pathologic response with a 3-year survival of 59% as compared to only 20 months in those patients who did not achieve a complete response (P = 0.037). Neoadjuvant chemotherapy administered concomitantly with conformal radiotherapy can be performed safely in the treatment of esophageal cancer, without increasing the operative morbidity, mortality, or length of stay. The higher complete response rates to neoadjuvant treatment (as compared to other reports) may be due to the use of three-dimensional conformal radiation therapy or the novel use of weekly carboplatin and paclitaxel. Copyright 2004 Wiley-Liss, Inc.

Accuracy of image guidance using free-breathing cone-beam computed tomography for stereotactic lung radiotherapy.

PubMed

Kamomae, Takeshi; Monzen, Hajime; Nakayama, Shinichi; Mizote, Rika; Oonishi, Yuuichi; Kaneshige, Soichiro; Sakamoto, Takashi

2015-01-01

Movement of the target object during cone-beam computed tomography (CBCT) leads to motion blurring artifacts. The accuracy of manual image matching in image-guided radiotherapy depends on the image quality. We aimed to assess the accuracy of target position localization using free-breathing CBCT during stereotactic lung radiotherapy. The Vero4DRT linear accelerator device was used for the examinations. Reference point discrepancies between the MV X-ray beam and the CBCT system were calculated using a phantom device with a centrally mounted steel ball. The precision of manual image matching between the CBCT and the averaged intensity (AI) images restructured from four-dimensional CT (4DCT) was estimated with a respiratory motion phantom, as determined in evaluations by five independent operators. Reference point discrepancies between the MV X-ray beam and the CBCT image-guidance systems, categorized as left-right (LR), anterior-posterior (AP), and superior-inferior (SI), were 0.33 ± 0.09, 0.16 ± 0.07, and 0.05 ± 0.04 mm, respectively. The LR, AP, and SI values for residual errors from manual image matching were -0.03 ± 0.22, 0.07 ± 0.25, and -0.79 ± 0.68 mm, respectively. The accuracy of target position localization using the Vero4DRT system in our center was 1.07 ± 1.23 mm (2 SD). This study experimentally demonstrated the sufficient level of geometric accuracy using the free-breathing CBCT and the image-guidance system mounted on the Vero4DRT. However, the inter-observer variation and systematic localization error of image matching substantially affected the overall geometric accuracy. Therefore, when using the free-breathing CBCT images, careful consideration of image matching is especially important.

Dosimetric Comparison of Intensity-Modulated Stereotactic Radiotherapy With Other Stereotactic Techniques for Locally Recurrent Nasopharyngeal Carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kung, Shiris Wai Sum; Wu, Vincent Wing Cheung; Kam, Michael Koon Ming, E-mail: kamkm@yahoo.co

2011-01-01

Purpose: Locally recurrent nasopharyngeal carcinoma (NPC) patients can be salvaged by reirradiation with a substantial degree of radiation-related complications. Stereotactic radiotherapy (SRT) is widely used in this regard because of its rapid dose falloff and high geometric precision. The aim of this study was to examine whether the newly developed intensity-modulated stereotactic radiotherapy (IMSRT) has any dosimetric advantages over three other stereotactic techniques, including circular arc (CARC), static conformal beam (SmMLC), and dynamic conformal arc (mARC), in treating locally recurrent NPC. Methods and Materials: Computed tomography images of 32 patients with locally recurrent NPC, previously treated with SRT, were retrievedmore » from the stereotactic planning system for contouring and computing treatment plans. Treatment planning of each patient was performed for the four treatment techniques: CARC, SmMLC, mARC, and IMSRT. The conformity index (CI) and homogeneity index (HI) of the planning target volume (PTV) and doses to the organs at risk (OARs) and normal tissue were compared. Results: All four techniques delivered adequate doses to the PTV. IMSRT, SmMLC, and mARC delivered reasonably conformal and homogenous dose to the PTV (CI <1.47, HI <0.53), but not for CARC (p < 0.05). IMSRT presented with the smallest CI (1.37) and HI (0.40). Among the four techniques, IMSRT spared the greatest number of OARs, namely brainstem, temporal lobes, optic chiasm, and optic nerve, and had the smallest normal tissue volume in the low-dose region. Conclusion: Based on the dosimetric comparison, IMSRT was optimal for locally recurrent NPC by delivering a conformal and homogenous dose to the PTV while sparing OARs.« less

Improvements in the radiotherapy of medulloblastoma, 1946 to 1975

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landberg, T.G.; Lindgren, M.L.; Cavallin-Staehl, E.K.

1980-02-01

The prognosis in medulloblastoma has often been reported to be gloomy, and five-year survival rates of approximately 25% are often reported. In recent years, however, some centers have published results that indicate a possible cure rate of 60% or even more. During the years 1946 to 1975, 50 children received radiotherapy for medulloblastoma at the University Hospital, Lund, Sweden. During this period the target volume had been defined in three different ways, whereas the target-absorbed doses had not differed. When only the demonstrated tumor was treated, the ten-year survival rate was 5%. If the spinal subdural space also was included,more » it rose to 25%, and when the whole subdural space was treated in addition to the demonstrated tumor, the projected ten-year survival rate was 53%. It is apparent that the target volume in the radiotherapy of medulloblastoma should include not only the demonstrated tumor but also the whole subdural space from the tip of the frontal lobes down to and including the second sacral segment. The size of the target-absorbed dose to be aimed at is not settled, but should consider not only the cure rate but also the performance status of the survivors. It seems from the present series that an absorbed dose of 45 Gy in not more than 30 fractions over six weeks to the demonstrated tumor and 30 Gy in 20 fractions over four weeks to the subdural space resulted in a fair frequency of tumor healing and minimal side effects. The delivery of this complicated treatment demands a high degree of precision in the technique. In this material the performance status of the children was not affected by the radiation treatment.« less

A client–server framework for 3D remote visualization of radiotherapy treatment space

PubMed Central

Santhanam, Anand P.; Min, Yugang; Dou, Tai H.; Kupelian, Patrick; Low, Daniel A.

2013-01-01

Radiotherapy is safely employed for treating wide variety of cancers. The radiotherapy workflow includes a precise positioning of the patient in the intended treatment position. While trained radiation therapists conduct patient positioning, consultation is occasionally required from other experts, including the radiation oncologist, dosimetrist, or medical physicist. In many circumstances, including rural clinics and developing countries, this expertise is not immediately available, so the patient positioning concerns of the treating therapists may not get addressed. In this paper, we present a framework to enable remotely located experts to virtually collaborate and be present inside the 3D treatment room when necessary. A multi-3D camera framework was used for acquiring the 3D treatment space. A client–server framework enabled the acquired 3D treatment room to be visualized in real-time. The computational tasks that would normally occur on the client side were offloaded to the server side to enable hardware flexibility on the client side. On the server side, a client specific real-time stereo rendering of the 3D treatment room was employed using a scalable multi graphics processing units (GPU) system. The rendered 3D images were then encoded using a GPU-based H.264 encoding for streaming. Results showed that for a stereo image size of 1280 × 960 pixels, experts with high-speed gigabit Ethernet connectivity were able to visualize the treatment space at approximately 81 frames per second. For experts remotely located and using a 100 Mbps network, the treatment space visualization occurred at 8–40 frames per second depending upon the network bandwidth. This work demonstrated the feasibility of remote real-time stereoscopic patient setup visualization, enabling expansion of high quality radiation therapy into challenging environments. PMID:23440605

The first clinical treatment with kilovoltage intrafraction monitoring (KIM): A real-time image guidance method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keall, Paul J., E-mail: paul.keall@sydney.edu.au; O’Brien, Ricky; Huang, Chen-Yu

Purpose: Kilovoltage intrafraction monitoring (KIM) is a real-time image guidance method that uses widely available radiotherapy technology, i.e., a gantry-mounted x-ray imager. The authors report on the geometric and dosimetric results of the first patient treatment using KIM which occurred on September 16, 2014. Methods: KIM uses current and prior 2D x-ray images to estimate the 3D target position during cancer radiotherapy treatment delivery. KIM software was written to process kilovoltage (kV) images streamed from a standard C-arm linear accelerator with a gantry-mounted kV x-ray imaging system. A 120° pretreatment kV imaging arc was acquired to build the patient-specific 2Dmore » to 3D motion correlation. The kV imager was activated during the megavoltage (MV) treatment, a dual arc VMAT prostate treatment, to estimate the 3D prostate position in real-time. All necessary ethics, legal, and regulatory requirements were met for this clinical study. The quality assurance processes were completed and peer reviewed. Results: During treatment, a prostate position offset of nearly 3 mm in the posterior direction was observed with KIM. This position offset did not trigger a gating event. After the treatment, the prostate motion was independently measured using kV/MV triangulation, resulting in a mean difference of less than 0.6 mm and standard deviation of less than 0.6 mm in each direction. The accuracy of the marker segmentation was visually assessed during and after treatment and found to be performing well. During treatment, there were no interruptions due to performance of the KIM software. Conclusions: For the first time, KIM has been used for real-time image guidance during cancer radiotherapy. The measured accuracy and precision were both submillimeter for the first treatment fraction. This clinical translational research milestone paves the way for the broad implementation of real-time image guidance to facilitate the detection and correction of geometric and dosimetric errors, and resultant improved clinical outcomes, in cancer radiotherapy.« less

Zoning of agricultural field using a fuzzy indicators model

USDA-ARS?s Scientific Manuscript database

Zoning of agricultural fields is an important task for utilization of precision farming technology. One method for deciding how to subdivide a field into a few relatively homogenous zones is using applications of fuzzy sets theory. Data collected from a precision agriculture study in central Texas...

Multi-atlas-based segmentation of the parotid glands of MR images in patients following head-and-neck cancer radiotherapy

NASA Astrophysics Data System (ADS)

Cheng, Guanghui; Yang, Xiaofeng; Wu, Ning; Xu, Zhijian; Zhao, Hongfu; Wang, Yuefeng; Liu, Tian

2013-02-01

Xerostomia (dry mouth), resulting from radiation damage to the parotid glands, is one of the most common and distressing side effects of head-and-neck cancer radiotherapy. Recent MRI studies have demonstrated that the volume reduction of parotid glands is an important indicator for radiation damage and xerostomia. In the clinic, parotid-volume evaluation is exclusively based on physicians' manual contours. However, manual contouring is time-consuming and prone to inter-observer and intra-observer variability. Here, we report a fully automated multi-atlas-based registration method for parotid-gland delineation in 3D head-and-neck MR images. The multi-atlas segmentation utilizes a hybrid deformable image registration to map the target subject to multiple patients' images, applies the transformation to the corresponding segmented parotid glands, and subsequently uses the multiple patient-specific pairs (head-and-neck MR image and transformed parotid-gland mask) to train support vector machine (SVM) to reach consensus to segment the parotid gland of the target subject. This segmentation algorithm was tested with head-and-neck MRIs of 5 patients following radiotherapy for the nasopharyngeal cancer. The average parotid-gland volume overlapped 85% between the automatic segmentations and the physicians' manual contours. In conclusion, we have demonstrated the feasibility of an automatic multi-atlas based segmentation algorithm to segment parotid glands in head-and-neck MR images.

Direct Downregulation of B-Cell Translocation Gene 3 by microRNA-93 Is Required for Desensitizing Esophageal Cancer to Radiotherapy.

PubMed

Cui, Hujun; Zhang, Shengqiang; Zhou, Hongbo; Guo, Ling

2017-08-01

Esophageal squamous carcinoma (ESC) is one of the most fatal malignancies worldwide with increasing occurrences yet poor outcome. MicroRNAs were reported to play roles in ESC. We aimed to understand how miRNAs affect the radiotherapy resistance of ESC. MicroRNA assays, real-time PCR, and Western blot were performed for expression analysis of miR-93 and BTG3. Luciferase activity assay was conducted with mutated B-cell translocation gene 3 (BTG3) 3'-UTR sequence in the 3' end of luciferase sequence with miR-93 inhibitor. ESC cells were treated with irradiation (IR) and clonogenic assay was utilized to detect the cell viability. Human ESC xenograft mouse model was established and subjected to target IR treatment followed by tumor size analysis. MiR-93 was decreased and BTG3 was increased in ESC cells, with negative correlation of their expression in ESC tissues. MiR-93 directly targeted BTG3 3'-UTR by luciferase activity assay. Either miR-93 inhibition or BTG3 overexpression decreased radiation resistance. Furthermore, miR-93 inhibition suppressed radiation resistance through BTG3. Direct downregulation of BTG3 by miR-93 is able to render ESC resistant to radiotherapy, and both BTG3 and miR-93 may potentially serve as clinical markers for ESC and contribute to the treatment of ESC.

Preoperative fiducial coil placement facilitates robot-assisted laparoscopic excision of retroperitoneal small solitary metastasis of kidney cancer.

PubMed

Agrawal, Vineet; Sharma, Ashwani; Wu, Guan

2014-11-01

Image-guided fiducial markers are being used in surgery, especially in spine and breast surgery, and radiotherapy, allowing localization of tumor sites precisely. We report a case of fiducial coil use in a man undergoing a robot-assisted laparoscopic resection of a metastatic nodule under the ipsilateral diaphragm after robot-assisted partial nephrectomy performed 2 years ago for a left upper pole renal tumor. The fiducial coil facilitated the localization of the lesion, which would otherwise have been challenging because of its small size and location. In addition, the fiducial coil was helpful to avoid cutting into the lesion directly. Copyright © 2014 Elsevier Inc. All rights reserved.

A Simple Approach to the Technical Aspects of Radiosurgery Treatments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prasad, S.C.; Bassano, D.A.; King, G.A.

2015-01-15

An approach to radiosurgery treatment that can be readily adopted in most radiotherapy centers with linear accelerators is presented. In our institution, a Leksell-type of neurosurgical frame, a computed tomography scanner, locally fabricated cones, and 6 MV X-ray beams are used to perform radiosurgery treatments. Collimated arcs with dose distributions that conform to the shape of the lesion in the transverse and the sagittal planes are used. It is argued that the uncertainties in the localization of the isocenter within a lesion and the specifications of the size of the target volume do not justify high precision mechanical devices formore » most radiosurgery treatments.« less

SBRT for recurrent head and neck cancer

NASA Astrophysics Data System (ADS)

Garg, M.; Kabarriti, R.; Baliga, S.; Guha, C.; Tome, W.; Kalnicki, S.

2017-01-01

The management of patients with recurrent head and neck cancers is complex. Concerns over toxicity with re-irradiation have limited its use in the clinical setting. Stereotactic Body Radiation Therapy (SBRT) has emerged as a highly conformal and precise type of radiotherapy and has the advantage of sparing normal tissue. Although SBRT is an attractive treatment modality, its use in the clinic is limited, given the technically challenging nature of the procedure. In this review, we attempt to provide a comprehensive overview of the role of re-irradiation in patients with recurrent head and neck cancers, with particular attention to the advent of SBRT and its use with systemic therapies such as cetuximab.

[Standard of care of carcinomas on cancer of unknown primary site in 2016].

PubMed

Benderra, Marc-Antoine; Ilié, Marius; Hofman, Paul; Massard, Christophe

2016-01-01

Patients with Cancer of unknown primary (cup) represent 2-10%, and have disseminated cancers for which we cannot find the primary site despite the clinical, pathological and radiological exams at our disposal. Diagnosis is based on a thorough clinical and histopathologic examination as well as new imaging techniques. Several clinicopathologic entities requiring specific treatment can be identified. Genome sequencing and liquid biopsy (circulating tumor cells and tumor free DNA) could allow further advances in the diagnosis. Therapeutically, in addition to surgery, radiotherapy and chemotherapy, precision medicine provides new therapeutic approaches. Copyright © 2016 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.

Utility of γH2AX as a molecular marker of DNA double-strand breaks in nuclear medicine: applications to radionuclide therapy employing auger electron-emitting isotopes.

PubMed

Mah, Li-Jeen; Orlowski, Christian; Ververis, Katherine; El-Osta, Assam; Karagiannis, Tom C

2011-01-01

There is an intense interest in the development of radiopharmaceuticals for cancer therapy. In particular, radiopharmaceuticals which involve targeting radionuclides specifically to cancer cells with the use of monoclonal antibodies (radioimmunotherapy) or peptides (targeted radiotherapy) are being widely investigated. For example, the ultra-short range Auger electron-emitting isotopes, which are discussed in this review, are being considered in the context of DNAtargeted radiotherapy. The efficient quantitative evaluation of the levels of damage caused by such potential radiopharmaceuticals is required for assessment of therapeutic efficacy and determination of relevant doses for successful treatment. The DNA double-strand break surrogate marker, γH2AX, has emerged as a useful biomonitor of damage and thus effectiveness of treatment, offering a highly specific and sensitive means of assessment. This review will cover the potential applications of γH2AX in nuclear medicine, in particular radionuclide therapy.

SU-D-18A-07: Towards 6-Degree-Of-Freedom Real-Time Motion Management in Cancer Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, C.Y.; Keall, P; Nasehi Tehrani, J

2014-06-01

Purpose: Lung tumor motion has been identified as a major issue that deteriorates treatment efficacy for radiotherapy, especially for SBRT. As tighter PTV margins are applied due to translational compensation, tumor rotation will become the dominant factor limiting tumor targeting accuracy. This is the world-first study quantifies lung tumor rotation by utilizing kV images with fiducial markers and a step towards 6-degree-of-freedom real-time cancer radiotherapy. Methods: Three or four gold coils were implanted as tumor surrogates in 3 lung cancer patients. 50 fractions of 8- minute, 10 Hz 4D CBCT projections were acquired for the patients immediately prior or aftermore » radiotherapy. The fiducial marker positions are segmented, reconstructed and used to determine tumour rotation by the iterative closest point algorithm. Different data acceptance and filtering methods were applied to accept data or smooth the marker trajectory. Results: The average rotation angles around the left/ right (LR), superior/inferior (SI), anterior/posterior (AP) rotations were found to be 0.8±4.2, -0.8±4.5 and 1.7±3.1 degrees respectively. For 28% of the treatment time, the lung tumors rotated more than 5° around the SI axis. Respiration-induced rotational motion was detected in 2 of the 3 lung patients. This can be explained by the patient developed atelectasis during the treatment period. Interestingly, no heart beating component of rotation was observed in the power spectrum. Different rotational types were observed within the patient cohort with large variations in the magnitude of the rotation between patients. Conclusions: For the first time, continuous tumor rotation has been measured for lung patients with gold fiducial markers. Tumors were found to undergo rotations of more than 5° for almost a third of the total treatment time. The study also demonstrated the feasibility of using continuously kV images for real-time lung tumour motion adaptive radiotherapy which can potentially reduce treatment margins and side effects. The authors acknowledge the financial support of an NHMRC Australia Fellowship.« less

Translating Legal Collocations in Contract Agreements by Iraqi EFL Students-Translators

ERIC Educational Resources Information Center

Abdulwahid, Muntaha A.; Hamzah, Zaitul Azma Binti Zainon; Hajimaming, Pabiyah; Alkhawaja, Hussein W.

2017-01-01

Legal translation of contract agreements is a challenge to translators as it involves combining the literary translation with the technical terminological precision. In translating legal contract agreements, a legal translator must utilize the lexical or syntactic precision and, more importantly, the pragmatic awareness of the context. This will…

Neuropsychological status in children and young adults with benign and low-grade brain tumors treated prospectively with focal stereotactic conformal radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jalali, Rakesh; Goswami, Savita; Sarin, Rajiv

2006-11-15

Purpose: To present prospective neuropsychological data at baseline and follow-up in children and young adults with benign and low-grade gliomas treated with focal stereotactic conformal radiotherapy (SCRT). Methods and Materials: A total of 22 patients (age 4-25 years) with residual/progressive benign and low-grade brain tumors considered suitable for SCRT underwent detailed and in-depth neuropsychological and cognitive testing at baseline before SCRT. The test battery included measurement of age-adjusted intelligence quotients (IQs) and cognitive parameters of visual, spatial, visuomotor, and attention concentrations. Anxiety was measured using the State-Trait Anxiety Inventory for Children and Hamilton Anxiety Rating Scale for patients >16 yearsmore » old. Patients were treated with high-precision conformal radiotherapy under stereotactic guidance to a dose of 54 Gy in 30 fractions. All neuropsychological assessments were repeated at 6 and 24 months after SCRT completion and compared with the baseline values. Results: The baseline mean full-scale IQ before starting RT for patients <16 years was 82 (range, 33-105). For those >16 years, the corresponding value was 72 (range, 64-129). Of 20 evaluable patients, 14 (70%) had less than average IQs at baseline, even before starting radiotherapy. The verbal IQ, performance IQ, and full-scale IQ, as well as other cognitive scores, did not change significantly at the 6- and 24-month follow-up assessments for all patients. The memory quotient in older children and young adults was maintained at 6 and 24 months after SCRT, with a mean value of 93 and 100, respectively, compared with a mean baseline value of 81 before RT. The mean anxiety score in children measured by the C1 and C2 components of the State-Trait Anxiety Inventory for Children (STAIC) was 48 and 40, respectively, which improved significantly to mean values of 30 and 26, respectively, at the 24-month follow-up assessment (p = 0.005). The mean depression score in patients >16 years old was 23 at baseline and had improved to 17 and 14 at the 6-month and 24-month follow-up assessments, respectively. Conclusion: Our data demonstrated neuropsychological impairment in a cohort of young patients with benign and low-grade tumors even before starting radiotherapy. SCRT, however, did not result in any additional worsening. These encouraging results need to be validated in a study with a larger number of patients and longer follow-up.« less

Determining sample size for tree utilization surveys

Treesearch

Stanley J. Zarnoch; James W. Bentley; Tony G. Johnson

2004-01-01

The U.S. Department of Agriculture Forest Service has conducted many studies to determine what proportion of the timber harvested in the South is actually utilized. This paper describes the statistical methods used to determine required sample sizes for estimating utilization ratios for a required level of precision. The data used are those for 515 hardwood and 1,557...

Using Public Data for Comparative Proteome Analysis in Precision Medicine Programs.

PubMed

Hughes, Christopher S; Morin, Gregg B

2018-03-01

Maximizing the clinical utility of information obtained in longitudinal precision medicine programs would benefit from robust comparative analyses to known information to assess biological features of patient material toward identifying the underlying features driving their disease phenotype. Herein, the potential for utilizing publically deposited mass-spectrometry-based proteomics data to perform inter-study comparisons of cell-line or tumor-tissue materials is investigated. To investigate the robustness of comparison between MS-based proteomics studies carried out with different methodologies, deposited data representative of label-free (MS1) and isobaric tagging (MS2 and MS3 quantification) are utilized. In-depth quantitative proteomics data acquired from analysis of ovarian cancer cell lines revealed the robust recapitulation of observable gene expression dynamics between individual studies carried out using significantly different methodologies. The observed signatures enable robust inter-study clustering of cell line samples. In addition, the ability to classify and cluster tumor samples based on observed gene expression trends when using a single patient sample is established. With this analysis, relevant gene expression dynamics are obtained from a single patient tumor, in the context of a precision medicine analysis, by leveraging a large cohort of repository data as a comparator. Together, these data establish the potential for state-of-the-art MS-based proteomics data to serve as resources for robust comparative analyses in precision medicine applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Technological advances in radiotherapy for cervical cancer.

PubMed

Walsh, Lorraine; Morgia, Marita; Fyles, Anthony; Milosevic, Michael

2011-09-01

To discuss the important technological advances that have taken place in the planning and delivery of both external beam radiotherapy and brachytherapy for patients with locally advanced cervical cancer, and the implications for improved clinical outcomes. Technological advances in external beam radiation treatment and brachytherapy for patients with cervical cancer allow more precise targeting of tumour and relative sparing of surrounding normal organs and tissues. Early evidence is emerging to indicate that these advances will translate into improvements in tumour control and reduced side effects. However, there are patient, tumour and treatment-related factors that can detract from these benefits. Foremost among these is complex, unpredictable and sometimes dramatic internal tumour and normal organ motion during treatment. The focus of current research and clinical development is on tracking internal anatomic change in individual patients and adapting treatment plans as required to assure that optimal tumour coverage and normal tissue sparing is maintained at all times. The success of this approach will depend on clear definitions of target volumes, high resolution daily soft tissue imaging, and new software tools for rapid contouring, treatment planning and quality assurance. Radiation treatment of locally advanced cervical cancer is evolving rapidly, driven by advances in technology, towards more individualized patient care that has the potential to substantially improve clinical outcomes.

Radiotherapy treatment planning: benefits of CT-MR image registration and fusion in tumor volume delineation.

PubMed

Djan, Igor; Petrović, Borislava; Erak, Marko; Nikolić, Ivan; Lucić, Silvija

2013-08-01

Development of imaging techniques, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET), made great impact on radiotherapy treatment planning by improving the localization of target volumes. Improved localization allows better local control of tumor volumes, but also minimizes geographical misses. Mutual information is obtained by registration and fusion of images achieved manually or automatically. The aim of this study was to validate the CT-MRI image fusion method and compare delineation obtained by CT versus CT-MRI image fusion. The image fusion software (XIO CMS 4.50.0) was applied to delineate 16 patients. The patients were scanned on CT and MRI in the treatment position within an immobilization device before the initial treatment. The gross tumor volume (GTV) and clinical target volume (CTV) were delineated on CT alone and on CT+MRI images consecutively and image fusion was obtained. Image fusion showed that CTV delineated on a CT image study set is mainly inadequate for treatment planning, in comparison with CTV delineated on CT-MRI fused image study set. Fusion of different modalities enables the most accurate target volume delineation. This study shows that registration and image fusion allows precise target localization in terms of GTV and CTV and local disease control.

Stereotactic radiosurgery of brain metastases.

PubMed

Specht, Hanno M; Combs, Stephanie E

2016-09-01

Brain metastases are a common problem in solid malignancies and still represent a major cause of morbidity and mortality. With the ongoing improvement in systemic therapies, the expectations on the efficacy of brain metastases directed treatment options are growing. As local therapies against brain metastases continue to evolve, treatment patterns have shifted from a palliative "one-treatment-fits-all" towards an individualized, patient adapted approach. In this article we review the evidence for stereotactic radiation treatment based on the current literature. Stereotactic radiosurgery (SRS) as a local high precision approach for the primary treatment of asymptomatic brain metastases has gained wide acceptance. It leads to lasting tumor control with only minor side effects compared to whole brain radiotherapy, since there is only little dose delivered to the healthy brain. The same holds true for hypofractionated stereotactic radiotherapy (HFSRT) for large metastases or for lesions close to organs at risk (e.g. the brainstem). New treatment indications such as neoadjuvant SRS followed by surgical resection or postoperative local therapy to the resection cavity show promising data and are also highlighted in this manuscript. With the evolution of local treatment options, optimal patient selection becomes more and more crucial. This article aims to aid decision making by outlining prognostic factors, treatment techniques and indications and common dose prescriptions.

Fast CPU-based Monte Carlo simulation for radiotherapy dose calculation.

PubMed

Ziegenhein, Peter; Pirner, Sven; Ph Kamerling, Cornelis; Oelfke, Uwe

2015-08-07

Monte-Carlo (MC) simulations are considered to be the most accurate method for calculating dose distributions in radiotherapy. Its clinical application, however, still is limited by the long runtimes conventional implementations of MC algorithms require to deliver sufficiently accurate results on high resolution imaging data. In order to overcome this obstacle we developed the software-package PhiMC, which is capable of computing precise dose distributions in a sub-minute time-frame by leveraging the potential of modern many- and multi-core CPU-based computers. PhiMC is based on the well verified dose planning method (DPM). We could demonstrate that PhiMC delivers dose distributions which are in excellent agreement to DPM. The multi-core implementation of PhiMC scales well between different computer architectures and achieves a speed-up of up to 37[Formula: see text] compared to the original DPM code executed on a modern system. Furthermore, we could show that our CPU-based implementation on a modern workstation is between 1.25[Formula: see text] and 1.95[Formula: see text] faster than a well-known GPU implementation of the same simulation method on a NVIDIA Tesla C2050. Since CPUs work on several hundreds of GB RAM the typical GPU memory limitation does not apply for our implementation and high resolution clinical plans can be calculated.

Quantification of tumor mobility during the breathing cycle using 3D dynamic MRI

NASA Astrophysics Data System (ADS)

Schoebinger, Max; Plathow, Christian; Wolf, Ivo; Kauczor, Hans-Ulrich; Meinzer, Hans-Peter

2006-03-01

Respiration causes movement and shape changes in thoracic tumors, which has a direct influence on the radio-therapy planning process. Current methods for the estimation of tumor mobility are either two-dimensional (fluoroscopy, 2D dynamic MRI) or based on radiation (3D (+t) CT, implanted gold markers). With current advances in dynamic MRI acquisition, 3D+t image sequences of the thorax can be acquired covering the thorax over the whole breathing cycle. In this work, methods are presented for the interactive segmentation of tumors in dynamic images, the calculation of tumor trajectories, dynamic tumor volumetry and dynamic tumor rotation/deformation based on 3D dynamic MRI. For volumetry calculation, a set of 21 related partial volume correcting volumetry algorithms has been evaluated based on tumor surrogates. Conventional volumetry based on voxel counting yielded a root mean square error of 29% compared to a root mean square error of 11% achieved by the algorithm performing best among the different volumetry methods. The new workflow has been applied to a set of 26 patients. Preliminary results indicate, that 3D dynamic MRI reveals important aspects of tumor behavior during the breathing cycle. This might imply the possibility to further improve high-precision radiotherapy techniques.

System and method for high precision isotope ratio destructive analysis

DOEpatents

Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R

2013-07-02

A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).

Precision Pointing Control System (PPCS) star tracker test

NASA Technical Reports Server (NTRS)

1972-01-01

Tests performed on the TRW precision star tracker are described. The unit tested was a two-axis gimballed star tracker designed to provide star LOS data to an accuracy of 1 to 2 sec. The tracker features a unique bearing system and utilizes thermal and mechanical symmetry techniques to achieve high precision which can be demonstrated in a one g environment. The test program included a laboratory evaluation of tracker functional operation, sensitivity, repeatibility, and thermal stability.

Defining Action Levels for In Vivo Dosimetry in Intraoperative Electron Radiotherapy.

PubMed

López-Tarjuelo, Juan; Morillo-Macías, Virginia; Bouché-Babiloni, Ana; Ferrer-Albiach, Carlos; Santos-Serra, Agustín

2016-06-01

In vivo dosimetry is recommended in intraoperative electron radiotherapy (IOERT). To perform real-time treatment monitoring, action levels (ALs) have to be calculated. Empirical approaches based on observation of samples have been reported previously, however, our aim is to present a predictive model for calculating ALs and to verify their validity with our experimental data. We considered the range of absorbed doses delivered to our detector by means of the percentage depth dose for the electron beams used. Then, we calculated the absorbed dose histograms and convoluted them with detector responses to obtain probability density functions in order to find ALs as certain probability levels. Our in vivo dosimeters were reinforced TN-502RDM-H mobile metal-oxide-semiconductor field-effect transistors (MOSFETs). Our experimental data came from 30 measurements carried out in patients undergoing IOERT for rectal, breast, sarcoma, and pancreas cancers, among others. The prescribed dose to the tumor bed was 90%, and the maximum absorbed dose was 100%. The theoretical mean absorbed dose was 90.3% and the measured mean was 93.9%. Associated confidence intervals at P = .05 were 89.2% and 91.4% and 91.6% and 96.4%, respectively. With regard to individual comparisons between the model and the experiment, 37% of MOSFET measurements lay outside particular ranges defined by the derived ALs. Calculated confidence intervals at P = .05 ranged from 8.6% to 14.7%. The model can describe global results successfully but cannot match all the experimental data reported. In terms of accuracy, this suggests an eventual underestimation of tumor bed bleeding or detector alignment. In terms of precision, it will be necessary to reduce positioning uncertainties for a wide set of location and treatment postures, and more precise detectors will be required. Planning and imaging tools currently under development will play a fundamental role. © The Author(s) 2015.

Carbon-ion radiotherapy for marginal lymph node recurrences of cervical cancer after definitive radiotherapy: a case report.

PubMed

Tamaki, Tomoaki; Ohno, Tatsuya; Kiyohara, Hiroki; Noda, Shin-ei; Ohkubo, Yu; Ando, Ken; Wakatsuki, Masaru; Kato, Shingo; Kamada, Tadashi; Nakano, Takashi

2013-04-05

Recurrences of cervical cancer after definitive radiotherapy often occur at common iliac or para-aortic lymph nodes as marginal lymph node recurrences. Patients with these recurrences have a chance of long-term survival by optimal re-treatment with radiotherapy. However, the re-irradiation often overlaps the initial and the secondary radiotherapy fields and can result in increased normal tissue toxicities in the bowels or the stomach. Carbon-ion radiotherapy, a form of particle beam radiotherapy using accelerated carbon ions, offers more conformal and sharp dose distribution than X-ray radiotherapy. Therefore, this approach enables the delivery of high radiation doses to the target while sparing its surrounding normal tissues. Marginal lymph node recurrences in common iliac lymph nodes after radiotherapy were treated successfully by carbon-ion radiotherapy in two patients. These two patients were initially treated with a combination of external beam radiotherapy and intracavitary and interstitial brachytherapy. However, the diseases recurred in the lymph nodes near the border of the initial radiotherapy fields after 22 months and 23 months. Because re-irradiation with X-ray radiotherapy may deliver high doses to a section of the bowels, carbon-ion radiotherapy was selected to treat the lymph node recurrences. A total dose of 48 Gy (RBE) in 12 fractions over 3 weeks was given to the lymph node recurrences, and the tumors disappeared completely with no severe acute toxicities. The two patients showed no evidence of disease for 75 months and 63 months after the initial radiotherapy and for 50 months and 37 months after the carbon-ion radiotherapy, respectively. No severe late adverse effects are observed in these patients. The two presented cases suggest that the highly conformal dose distribution of carbon-ion radiotherapy may be beneficial in the treatment of marginal lymph node recurrences after radiotherapy. In addition, the higher biological effect of carbon-ion radiotherapy and its superior dose distribution may provide more effective tumor control in treatment for re-irradiation of the marginal recurrences in radiation resistant tumors other than cervical cancer.

Multifrequency high precise subTHz-THz-IR spectroscopy for exhaled breath research

NASA Astrophysics Data System (ADS)

Vaks, Vladimir L.; Domracheva, Elena G.; Pripolzin, Sergey I.; Chernyaeva, Mariya B.

2016-09-01

Nowadays the development of analytical spectroscopy with high performance, sensitivity and spectral resolution for exhaled breath research is attended. The method of two-frequency high precise THz spectroscopy and the method of high precise subTHz-THz-IR spectroscopy are presented. Development of a subTHz-THz-IR gas analyzer increases the number of gases that can be identified and the reliability of the detection by confirming the signature in both THz and MIR ranges. The testing measurements have testified this new direction of analytical spectroscopy to open widespread trends of its using for various problems of medicine and biology. First of all, there are laboratory investigations of the processes in exhaled breath and studying of their dynamics. Besides, the methods presented can be applied for detecting intermediate and short time living products of reactions in exhaled breath. The spectrometers have been employed for investigations of acetone, methanol and ethanol in the breath samples of healthy volunteers and diabetes patients. The results have demonstrated an increased concentration of acetone in breath of diabetes patients. The dynamic of changing the acetone concentration before and after taking the medicines is discovered. The potential markers of pre-cancer states and oncological diseases of gastrointestinal tract organs have been detected. The changes in the NO concentration in exhaled breath of cancer patients during radiotherapy as well as increase of the NH3 concentration at gastrointestinal diseases have been revealed. The preliminary investigations of biomarkers in three frequency ranges have demonstrated the advantages of the multifrequency high precise spectroscopy for noninvasive medical diagnostics.

Feasibility of Adaptive MR-guided Stereotactic Body Radiotherapy (SBRT) of Lung Tumors

PubMed Central

Simpson, Garrett N; Llorente, Ricardo; Samuels, Michael A; Dogan, Nesrin

2018-01-01

Online adaptive radiotherapy (ART) with frequent imaging has the potential to improve dosimetric accuracy by accounting for anatomical and functional changes during the course of radiotherapy. Presented are three interesting cases that provide an assessment of online adaptive magnetic resonance-guided radiotherapy (MRgRT) for lung stereotactic body radiotherapy (SBRT). The study includes three lung SBRT cases, treated on an MRgRT system where MR images were acquired for planning and prior to each treatment fraction. Prescription dose ranged from 48 to 50 Gy in four to five fractions, normalized to where 95% of the planning target volume (PTV) was covered by 100% of the prescription dose. The process begins with the gross tumor volume (GTV), PTV, spinal cord, lungs, heart, and esophagus being delineated on the planning MRI. The treatment plan was then generated using a step-and-shoot intensity modulated radiotherapy (IMRT) technique, which utilized a Monte Carlo dose calculation. Next, the target and organs at risk (OAR) contours from the planning MRI were deformably propagated to the daily setup MRIs. These deformed contours were reviewed and modified by the physician. To determine the efficacy of ART, two different strategies were explored: 1) Calculating the plan created for the planning MR on each fraction setup MR dataset (Non-Adapt) and 2) creating a new optimized IMRT plan on the fraction setup MR dataset (FxAdapt). The treatment plans from both strategies were compared using the clinical dose-volume constraints. PTV coverage constraints were not met for 33% Non-Adapt fractions; all FxAdapt fractions met this constraint. Eighty-eight percent of all OAR constraints studied were better on FxAdapt plans, while 12% of OAR constraints were superior on Non-Adapt fractions. The OAR that garnered the largest benefit would be the uninvolved lung, with superior sparing in 92% of the FxAdapt studied. Similar, but less pronounced, benefits from adaptive planning were experienced for the spinal cord, chest wall, and esophagus. Online adaptive MR-guided lung SBRT can provide better target conformality and homogeneity and OAR sparing compared with non-adaptive SBRT in selected cases. Conversely, if the PTV isn’t adjacent to multiple OARs, then the benefit from ART may be limited. Further studies, which incorporate a larger cohort of patients with uniform prescriptions, are needed to thoroughly evaluate the benefits of daily online ART during MRgRT. PMID:29872603

Feasibility study of proton-based quality assurance of proton range compensator

NASA Astrophysics Data System (ADS)

Park, S.; Jeong, C.; Min, B. J.; Kwak, J.; Lee, J.; Cho, S.; Shin, D.; Lim, Y. K.; Park, S. Y.; Lee, S. B.

2013-06-01

All patient specific range compensators (RCs) are customized for achieving distal dose conformity of target volume in passively scattered proton therapy. Compensators are milled precisely using a computerized machine. In proton therapy, precision of the compensator is critical and quality assurance (QA) is required to protect normal tissues and organs from radiation damage. This study aims to evaluate the precision of proton-based quality assurance of range compensator. First, the geometry information of two compensators was extracted from the DICOM Radiotherapy (RT) plan. Next, RCs were irradiated on the EBT film individually by proton beam which is modulated to have a photon-like percent depth dose (PDD). Step phantoms were also irradiated on the EBT film to generate calibration curve which indicates relationship between optical density of irradiated film and perpendicular depth of compensator. Comparisons were made using the mean absolute difference (MAD) between coordinate information from DICOM RT and converted depth information from the EBT film. MAD over the whole region was 1.7, and 2.0 mm. However, MAD over the relatively flat regions on each compensator selected for comparison was within 1 mm. These results shows that proton-based quality assurance of range compensator is feasible and it is expected to achieve MAD over the whole region less than 1 mm with further correction about scattering effect of proton imaging.

PD-1/PD-L blockade in gastrointestinal cancers: lessons learned and the road toward precision immunotherapy.

PubMed

Long, Junyu; Lin, Jianzhen; Wang, Anqiang; Wu, Liangcai; Zheng, Yongchang; Yang, Xiaobo; Wan, Xueshuai; Xu, Haifeng; Chen, Shuguang; Zhao, Haitao

2017-08-03

Gastrointestinal (GI) malignancies are the most prevalent tumors worldwide, with increasing incidence and mortality. Although surgical resection, chemotherapy, radiotherapy, and molecular targeted therapy have led to significant advances in the treatment of GI cancer patients, overall survival is still low. Therefore, alternative strategies must be identified to improve patient outcomes. In the tumor microenvironment, tumor cells can escape the host immune response through the interaction of PD-1 and PD-L, which inhibits the function of T cells and tumor-infiltrating lymphocytes while increasing the function of immunosuppressive T regulatory cells. The use of an anti-PD-1/PD-L blockade enables reprogramming of the immune system to efficiently identify and kill tumor cells. In recent years, the efficacy of PD-1/PD-L blockade has been demonstrated in many tumors, and this treatment is expected to be a pan-immunotherapy for tumors. Here, we review the signaling pathway underlying the dysregulation of PD-1/PD-L in tumors, summarize the current clinical data for PD-1/PD-L inhibitors in GI malignancies, and discuss road toward precision immunotherapy in relation to PD-1/PD-L blockade. The preliminary data for PD-1/PD-L inhibitors are encouraging, and the precision immunotherapy of PD-1/PD-L inhibitors will be a viable and pivotal clinical strategy for GI cancer therapy.

Xerostomia, salivary characteristics and gland volumes following intensity-modulated radiotherapy for nasopharyngeal carcinoma: a two-year follow up.

PubMed

Sim, Cpc; Soong, Y L; Pang, Epp; Lim, C; Walker, G D; Manton, D J; Reynolds, E C; Wee, Jts

2018-06-01

To evaluate changes in xerostomia status, salivary characteristics and gland volumes 2 years following radiotherapy in nasopharyngeal carcinoma patients. Xerostomia scores, salivary flow rates, pH and buffering capacity were measured at pre-radiotherapy, mid-radiotherapy, 2 weeks, 3 months and 2 years post-radiotherapy. Salivary gland volumes and their correlation with radiation dose were also assessed. Mean radiation dose to oral cavity, parotid and submandibular glands (SMG) was 44.5, 65.0 and 38.6 Gy respectively. Parotid and SMG volumes decreased 33% at 3 months post-radiotherapy; volumes at 2 years post-radiotherapy were 84% and 51% of pre-radiotherapy levels, respectively. Correlations were observed between parotid gland volume per cent reduction and its radiation dose and between resting salivary flow rate reduction and post-radiotherapy/pre-radiotherapy SMG volume ratio. Salivary flow rates and resting saliva pH remained significantly low at 2 years post-radiotherapy (both flow rates, P = 0.001; resting saliva pH, P = 0.005). Similarly, xerostomia scores remained significantly higher compared with pre-radiotherapy levels. Submandibular gland volumetric shrinkage persisted 2 years after radiotherapy. Xerostomia scores remained significantly higher, and salivary flow rates and resting saliva pH remained significantly lower, suggesting that study participants were still at risk for hyposalivation-related oral diseases. © 2018 Australian Dental Association.

Discrimination of Dynamic Tactile Contact by Temporally Precise Event Sensing in Spiking Neuromorphic Networks

PubMed Central

Lee, Wang Wei; Kukreja, Sunil L.; Thakor, Nitish V.

2017-01-01

This paper presents a neuromorphic tactile encoding methodology that utilizes a temporally precise event-based representation of sensory signals. We introduce a novel concept where touch signals are characterized as patterns of millisecond precise binary events to denote pressure changes. This approach is amenable to a sparse signal representation and enables the extraction of relevant features from thousands of sensing elements with sub-millisecond temporal precision. We also proposed measures adopted from computational neuroscience to study the information content within the spiking representations of artificial tactile signals. Implemented on a state-of-the-art 4096 element tactile sensor array with 5.2 kHz sampling frequency, we demonstrate the classification of transient impact events while utilizing 20 times less communication bandwidth compared to frame based representations. Spiking sensor responses to a large library of contact conditions were also synthesized using finite element simulations, illustrating an 8-fold improvement in information content and a 4-fold reduction in classification latency when millisecond-precise temporal structures are available. Our research represents a significant advance, demonstrating that a neuromorphic spatiotemporal representation of touch is well suited to rapid identification of critical contact events, making it suitable for dynamic tactile sensing in robotic and prosthetic applications. PMID:28197065

Utilization of thermoluminescent dosimetry in total skin electron beam radiotherapy of mycosis fungoides.

PubMed

Antolak, J A; Cundiff, J H; Ha, C S

1998-01-01

The purpose of this report is to discuss the utilization of thermoluminescent dosimetry (TLD) in total skin electron beam (TSEB) radiotherapy to: (a) compare patient dose distributions for similar techniques on different machines, (b) confirm beam calibration and monitor unit calculations, (c) provide data for making clinical decisions, and (d) study reasons for variations in individual dose readings. We report dosimetric results for 72 cases of mycosis fungoides, using similar irradiation techniques on two different linear accelerators. All patients were treated using a modified Stanford 6-field technique. In vivo TLD was done on all patients, and the data for all patients treated on both machines was collected into a database for analysis. Means and standard deviations (SDs) were computed for all locations. Scatter plots of doses vs. height, weight, and obesity index were generated, and correlation coefficients with these variables were computed. The TLD results show that our current TSEB implementation is dosimetrically equivalent to the previous implementation, and that our beam calibration technique and monitor unit calculation is accurate. Correlations with obesity index were significant at several sites. Individual TLD results allow us to customize the boost treatment for each patient, in addition to revealing patient positioning problems and/or systematic variations in dose caused by patient variability. The data agree well with previously published TLD results for similar TSEB techniques. TLD is an important part of the treatment planning and quality assurance programs for TSEB, and routine use of TLD measurements for TSEB is recommended.

The utility of e-Learning to support training for a multicentre bladder online adaptive radiotherapy trial (TROG 10.01-BOLART).

PubMed

Foroudi, Farshad; Pham, Daniel; Bressel, Mathias; Tongs, David; Rolfo, Aldo; Styles, Colin; Gill, Suki; Kron, Tomas

2013-10-01

An e-Learning programme appeared useful for providing training and information regarding a multi-centre image guided radiotherapy trial. The aim of this study is to demonstrate the utility of this e-Learning programme. Modules were created on relevant pelvic anatomy, Cone Beam CT soft tissue recognition and trial details. Radiation therapist participants' knowledge and confidence were evaluated before, at the end of, and after at least 6 weeks of e-Learning (long term). One hundred and eighty-five participants were recruited from 12 centres, with 118 in the first, and 67 in the second cohort. One hundred and forty-six participants had two tests (pre and post e-Learning) and 39 of these had three tests (pre, post, and long term). There was an increase confidence after completion of modules (p<0.001). The first cohort pre scores increased from 67 ± 11 to 79 ± 8 (p<0.001) post. The long term same question score was 73 ± 14 (p=0.025, comparing to pre-test), and different questions' score was 77 ± 13 (p=0.014). In the second cohort, pre-test scores were 64 ± 10, post-test same question score 78 ± 9 (p<0.001) and different questions' score 81 ± 11 (p<0.001). e-Learning for a multi-centre clinical trial was feasible and improved confidence and knowledge. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Precision Medicine, Cardiovascular Disease and Hunting Elephants.

PubMed

Joyner, Michael J

2016-01-01

Precision medicine postulates improved prediction, prevention, diagnosis and treatment of disease based on patient specific factors especially DNA sequence (i.e., gene) variants. Ideas related to precision medicine stem from the much anticipated "genetic revolution in medicine" arising seamlessly from the human genome project (HGP). In this essay I deconstruct the concept of precision medicine and raise questions about the validity of the paradigm in general and its application to cardiovascular disease. Thus far precision medicine has underperformed based on the vision promulgated by enthusiasts. While niche successes for precision medicine are likely, the promises of broad based transformation should be viewed with skepticism. Open discussion and debate related to precision medicine are urgently needed to avoid misapplication of resources, hype, iatrogenic interventions, and distraction from established approaches with ongoing utility. Failure to engage in such debate will lead to negative unintended consequences from a revolution that might never come. Copyright © 2016 Elsevier Inc. All rights reserved.

Dosimetric comparison of carbon ion and X-ray radiotherapy for Stage IIIA non-small cell lung cancer.

PubMed

Kubo, Nobuteru; Saitoh, Jun-Ichi; Shimada, Hirofumi; Shirai, Katsuyuki; Kawamura, Hidemasa; Ohno, Tatsuya; Nakano, Takashi

2016-09-01

The present study compared the dose-volume histograms of patients with Stage IIIA non-small cell lung cancer (NSCLC) treated with carbon ion radiotherapy with those of patients treated with X-ray radiotherapy. Patients with Stage IIIA NSCLC (n = 10 patients for each approach) were enrolled. Both radiotherapy plans were calculated with the same targets and organs at risk on the same CT. The treatment plan for the prophylactic lymph node and primary tumor (PTV1) delivered 40 Gy for X-ray radiotherapy and 40 Gy (relative biological effectiveness; RBE) for carbon ion radiotherapy. The total doses for the primary tumor and clinically positive lymph nodes (PTV2) were 60 Gy for X-ray radiotherapy and 60 Gy (RBE) for carbon ion radiotherapy. The homogeneity indexes for PTV1 and PTV2 were superior for carbon ion radiotherapy in comparison with X-ray radiotherapy (PTV1, 0.57 vs 0.65, P = 0.009; PTV2, 0.07 vs 0.16, P = 0.005). The normal lung mean dose, V5, V10 and V20 for carbon ion radiotherapy were 7.7 Gy (RBE), 21.4%, 19.7% and 17.0%, respectively, whereas the corresponding doses for X-ray radiotherapy were 11.9 Gy, 34.9%, 26.6% and 20.8%, respectively. Maximum spinal cord dose, esophageal maximum dose and V50, and bone V10, V30 and V50 were lower with carbon ion radiotherapy than with X-ray radiotherapy. The present study indicates that carbon ion radiotherapy provides a more homogeneous target dose and a lower dose to organs at risk than X-ray radiotherapy for Stage IIIA non-small cell lung cancer. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Contemporary role of radiotherapy in the management of penile cancer

PubMed Central

Korzeniowski, Martin Arthur

2017-01-01

Penile cancer is a rare clinical entity that contributes to significant patient morbidity and mortality. Human papilloma virus (HPV) plays an important role in the carcinogenesis of penile squamous cell carcinoma (SCC), is associated with improved clinical outcomes, and is predictive for response to treatment with chemotherapy and radiotherapy. Historically, treatment consisted of radical surgery with partial or total penectomy. While effective for local control, surgical resection can impart significant physical, psychological and sexual dysfunction for afflicted men. Organ preservation strategies offer significant quality of life advantages over standard surgery and can be utilized without compromising oncological control. As an alternative or adjunct to surgical resection, radiation therapy can be used for organ preservation strategies successfully in up to 70% of patients. A variety of treatment techniques can be employed depending on the location and burden of disease. Limited disease can be amenable to treatment with interstitial brachytherapy, surface mold plesiotherapy or external beam radiotherapy. For locally advanced presentations, or for patients not amenable to surgical resection, excellent clinical outcomes can be achieved using a combination of chemotherapy and radiation therapy. Here, we discuss the management of penile SCC using modern radiation therapy treatment techniques, the expected clinical outcomes for organ preservation, as well as the management of side-effects and toxicities. While large randomized trials are being developed, the management of penile cancer is informed from the management of other of other anogenital malignancies, which we also review. PMID:29184783

WE-EF-BRD-00: New Developments in Hybrid MR-Treatment: Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2015-06-15

MRI-guided treatment is a growing area of medicine, particularly in radiotherapy and surgery. The exquisite soft tissue anatomic contrast offered by MRI, along with functional imaging, makes the use of MRI during therapeutic procedures very attractive. Challenging the utility of MRI in the therapy room are many issues including the physics of MRI and the impact on the environment and therapeutic instruments, the impact of the room and instruments on the MRI; safety, space, design and cost. In this session, the applications and challenges of MRI-guided treatment will be described. The session format is: Past, present and future: MRI-guided radiotherapymore » from 2005 to 2025: Jan Lagendijk Battling Maxwell’s equations: Physics challenges and solutions for hybrid MRI systems: Paul Keall I want it now!: Advances in MRI acquisition, reconstruction and the use of priors to enable fast anatomic and physiologic imaging to inform guidance and adaptation decisions: Yanle Hu MR in the OR: The growth and applications of MRI for interventional radiology and surgery: Rebecca Fahrig Learning Objectives: To understand the history and trajectory of MRI-guided radiotherapy To understand the challenges of integrating MR imaging systems with linear accelerators To understand the latest in fast MRI methods to enable the visualisation of anatomy and physiology on radiotherapy treatment timescales To understand the growing role and challenges of MRI for image-guided surgical procedures My disclosures are publicly available and updated at: http://sydney.edu.au/medicine/radiation-physics/about-us/disclosures.php.« less

Perspectives on the combination of radiotherapy and targeted therapy with DNA repair inhibitors in the treatment of pancreatic cancer

PubMed Central

Yang, Shih-Hung; Kuo, Ting-Chun; Wu, Hsu; Guo, Jhe-Cyuan; Hsu, Chiun; Hsu, Chih-Hung; Tien, Yu-Wen; Yeh, Kun-Huei; Cheng, Ann-Lii; Kuo, Sung-Hsin

2016-01-01

Pancreatic cancer is highly lethal. Current research that combines radiation with targeted therapy may dramatically improve prognosis. Cancerous cells are characterized by unstable genomes and activation of DNA repair pathways, which are indicated by increased phosphorylation of numerous factors, including H2AX, ATM, ATR, Chk1, Chk2, DNA-PKcs, Rad51, and Ku70/Ku80 heterodimers. Radiotherapy causes DNA damage. Cancer cells can be made more sensitive to the effects of radiation (radiosensitization) through inhibition of DNA repair pathways. The synergistic effects, of two or more combined non-lethal treatments, led to co-administration of chemotherapy and radiosensitization in BRCA-defective cells and patients, with promising results. ATM/Chk2 and ATR/Chk1 pathways are principal regulators of cell cycle arrest, following DNA double-strand or single-strand breaks. DNA double-stranded breaks activate DNA-dependent protein kinase, catalytic subunit (DNA-PKcs). It forms a holoenzyme with Ku70/Ku80 heterodimers, called DNA-PK, which catalyzes the joining of nonhomologous ends. This is the primary repair pathway utilized in human cells after exposure to ionizing radiation. Radiosensitization, induced by inhibitors of ATM, ATR, Chk1, Chk2, Wee1, PP2A, or DNA-PK, has been demonstrated in preclinical pancreatic cancer studies. Clinical trials are underway. Development of agents that inhibit DNA repair pathways to be clinically used in combination with radiotherapy is warranted for the treatment of pancreatic cancer. PMID:27621574

TU-AB-BRC-10: Modeling of Radiotherapy Linac Source Terms Using ARCHER Monte Carlo Code: Performance Comparison of GPU and MIC Computing Accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, T; Lin, H; Xu, X

Purpose: (1) To perform phase space (PS) based source modeling for Tomotherapy and Varian TrueBeam 6 MV Linacs, (2) to examine the accuracy and performance of the ARCHER Monte Carlo code on a heterogeneous computing platform with Many Integrated Core coprocessors (MIC, aka Xeon Phi) and GPUs, and (3) to explore the software micro-optimization methods. Methods: The patient-specific source of Tomotherapy and Varian TrueBeam Linacs was modeled using the PS approach. For the helical Tomotherapy case, the PS data were calculated in our previous study (Su et al. 2014 41(7) Medical Physics). For the single-view Varian TrueBeam case, we analyticallymore » derived them from the raw patient-independent PS data in IAEA’s database, partial geometry information of the jaw and MLC as well as the fluence map. The phantom was generated from DICOM images. The Monte Carlo simulation was performed by ARCHER-MIC and GPU codes, which were benchmarked against a modified parallel DPM code. Software micro-optimization was systematically conducted, and was focused on SIMD vectorization of tight for-loops and data prefetch, with the ultimate goal of increasing 512-bit register utilization and reducing memory access latency. Results: Dose calculation was performed for two clinical cases, a Tomotherapy-based prostate cancer treatment and a TrueBeam-based left breast treatment. ARCHER was verified against the DPM code. The statistical uncertainty of the dose to the PTV was less than 1%. Using double-precision, the total wall time of the multithreaded CPU code on a X5650 CPU was 339 seconds for the Tomotherapy case and 131 seconds for the TrueBeam, while on 3 5110P MICs it was reduced to 79 and 59 seconds, respectively. The single-precision GPU code on a K40 GPU took 45 seconds for the Tomotherapy dose calculation. Conclusion: We have extended ARCHER, the MIC and GPU-based Monte Carlo dose engine to Tomotherapy and Truebeam dose calculations.« less

Stereotactic body radiotherapy for lung cancer: how much does it really cost?

PubMed

Lievens, Yolande; Obyn, Caroline; Mertens, Anne-Sophie; Van Halewyck, Dries; Hulstaert, Frank

2015-03-01

Despite the lack of randomized evidence, stereotactic body radiotherapy (SBRT) is being accepted as superior to conventional radiotherapy for patients with T1-2N0 non-small-cell lung cancer in the periphery of the lung and unfit or unwilling to undergo surgery. To introduce SBRT in a system of coverage with evidence development, a correct financing had to be determined. A time-driven activity-based costing model for radiotherapy was developed. Resource cost calculation of all radiotherapy treatments, standard and innovative, was conducted in 10 Belgian radiotherapy centers in the second half of 2012. The average cost of lung SBRT across the 10 centers (6221&OV0556;) is in the range of the average costs of standard fractionated 3D-conformal radiotherapy (5919&OV0556;) and intensity-modulated radiotherapy (7379&OV0556;) for lung cancer. Hypofractionated 3D-conformal radiotherapy and intensity-modulated radiotherapy schemes are less costly (3993&OV0556; respectively 4730&OV0556;). The SBRT cost increases with the number of fractions and is highly dependent of personnel and equipment use. SBRT cost varies more by centre than conventional radiotherapy cost, reflecting different technologies, stages in the learning curve and a lack of clear guidance in this field. Time-driven activity-based costing of radiotherapy is feasible in a multicentre setup, resulting in real-life resource costs that can form the basis for correct reimbursement schemes, supporting an early yet controlled introduction of innovative radiotherapy techniques in clinical practice.

Hands-on Precision Agriculture Data Management Workshops for Producers and Industry Professionals: Development and Assessment

ERIC Educational Resources Information Center

Luck, Joe D.; Fulton, John P.; Rees, Jennifer

2015-01-01

Three Precision Agriculture Data Management workshops regarding yield monitor data were conducted in 2014, reaching 62 participants. Post-workshop surveys (n = 58) indicated 73% of respondents experienced a moderate to significant increase in knowledge related to yield monitor data usage. Another 72% reported that they planned to utilize best…

Integrated titer plate-injector head for microdrop array preparation, storage and transfer

DOEpatents

Swierkowski, Stefan P.

2000-01-01

An integrated titer plate-injector head for preparing and storing two-dimensional (2-D) arrays of microdrops and for ejecting part or all of the microdrops and inserting same precisely into 2-D arrays of deposition sites with micrometer precision. The titer plate-injector head includes integrated precision formed nozzles with appropriate hydrophobic surface features and evaporative constraints. A reusable pressure head with a pressure equalizing feature is added to the titer plate to perform simultaneous precision sample ejection. The titer plate-injector head may be utilized in various applications including capillary electrophoresis, chemical flow injection analysis, microsample array preparation, etc.

Percentage of Cancer Volume in Biopsy Cores Is Prognostic for Prostate Cancer Death and Overall Survival in Patients Treated With Dose-Escalated External Beam Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vance, Sean M.; Stenmark, Matthew H.; Blas, Kevin

2012-07-01

Purpose: To investigate the prognostic utility of the percentage of cancer volume (PCV) in needle biopsy specimens for prostate cancer patients treated with dose-escalated external beam radiotherapy. Methods and Materials: The outcomes were analyzed for 599 men treated for localized prostate cancer with external beam radiotherapy to a minimal planning target volume dose of 75 Gy (range, 75-79.2). We assessed the effect of PCV and the pretreatment and treatment-related factors on the freedom from biochemical failure, freedom from metastasis, cause-specific survival, and overall survival. Results: The median number of biopsy cores was 7 (interquartile range, 6-12), median PCV was 10%more » (interquartile range, 2.5-25%), and median follow-up was 62 months. The PCV correlated with the National Comprehensive Cancer Network risk group and individual risk features, including T stage, prostate-specific antigen level, Gleason score, and percentage of positive biopsy cores. On log-rank analysis, the PCV stratified by quartile was prognostic for all endpoints, including overall survival. In addition, the PCV was a stronger prognostic factor than the percentage of positive biopsy cores when the two metrics were analyzed together. On multivariate analysis, the PCV predicted a worse outcome for all endpoints, including freedom from biochemical failure, (hazard ratio, 1.9; p = .0035), freedom from metastasis (hazard ratio, 1.7, p = .09), cause-specific survival (hazard ratio, 3.9, p = .014), and overall survival (hazard ratio, 1.8, p = .02). Conclusions: For patients treated with dose-escalated external beam radiotherapy, the volume of cancer in the biopsy specimen adds prognostic value for clinically relevant endpoints, particularly in intermediate- and high-risk patients. Although the PCV determination is more arduous than the percentage of positive biopsy cores, it provides superior risk stratification.« less

Pretreatment Endorectal Coil Magnetic Resonance Imaging Findings Predict Biochemical Tumor Control in Prostate Cancer Patients Treated With Combination Brachytherapy and External-Beam Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riaz, Nadeem; Afaq, Asim; Akin, Oguz

Purpose: To investigate the utility of endorectal coil magenetic resonance imaging (eMRI) in predicting biochemical relapse in prostate cancer patients treated with combination brachytherapy and external-beam radiotherapy. Methods and Materials: Between 2000 and 2008, 279 men with intermediate- or high-risk prostate cancer underwent eMRI of their prostate before receiving brachytherapy and supplemental intensity-modulated radiotherapy. Endorectal coil MRI was performed before treatment and retrospectively reviewed by two radiologists experienced in genitourinary MRI. Image-based variables, including tumor diameter, location, number of sextants involved, and the presence of extracapsular extension (ECE), were incorporated with other established clinical variables to predict biochemical control outcomes.more » The median follow-up was 49 months (range, 1-13 years). Results: The 5-year biochemical relapse-free survival for the cohort was 92%. Clinical findings predicting recurrence on univariate analysis included Gleason score (hazard ratio [HR] 3.6, p = 0.001), PSA (HR 1.04, p = 0.005), and National Comprehensive Cancer Network risk group (HR 4.1, p = 0.002). Clinical T stage and the use of androgen deprivation therapy were not correlated with biochemical failure. Imaging findings on univariate analysis associated with relapse included ECE on MRI (HR 3.79, p = 0.003), tumor size (HR 2.58, p = 0.04), and T stage (HR 1.71, p = 0.004). On multivariate analysis incorporating both clinical and imaging findings, only ECE on MRI and Gleason score were independent predictors of recurrence. Conclusions: Pretreatment eMRI findings predict for biochemical recurrence in intermediate- and high-risk prostate cancer patients treated with combination brachytherapy and external-beam radiotherapy. Gleason score and the presence of ECE on MRI were the only significant predictors of biochemical relapse in this group of patients.« less

WE-E-BRE-02: BEST IN PHYSICS (THERAPY) - Stereotactic Radiotherapy for Renal Sympathetic Ablation for the Treatment of Refractory Hypertension

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maxim, P; Wheeler, M; Loo, B

Purpose: To determine the safety and efficacy of stereotactic radiotherapy as a novel treatment for patients with refractory hypertension in a swine model. Uncontrolled hypertension is a significant contributor to morbidity and mortality, substantially increasing the risk of ischemic stroke, ischemic heart disease, and kidney failure. Methods: High-resolution computed tomography (CT) images of anesthetized pigs were acquired and treatment plans for each renal artery and nerve were developed using our clinically implemented treatment planning system. Stereotactic radiotherapy, 40Gy in single fraction was delivered bilaterally to the renal nerves using a state-of-the-art medical linear accelerator under image guidance utilizing dynamic conformalmore » arcs. Dose to nearby critical organs was evaluated by dosevolume histogram analysis and correlated to toxicity data obtained through follow up pathology analysis. The animals were observed for six months with serial measurements of blood pressure, urine analysis, serum laboratories, and overall clinical and behavioral status. Results: All animals survived to the follow-up point without evidence of renal dysfunction (stable serum creatinine), skin changes, or behavioral changes that might suggest animal discomfort. Plasma norepinephrine levels (ng/ml) were followed monthly for 6 months. The average reduction observed was 63%, with the median reduction at 73.5%. Microscopic evaluation 4–6 weeks after treatment showed evidence of damage to the nerves around treated renal arteries. Considerable attenuation in pan neurofilament expression by immunohistochemistry was observed with some vacuolar changes indicative of injury. There was no histological or immunohistochemical evidence of damage to nearby spinal cord or spinal nerve root structures. Conclusion: Our preclinical studies have shown stereotactic radiotherapy to the renal sympathetic plexus to be safe and effective in reducing blood pressure, thus this approach holds great promise as a novel treatment modality for patients with refractory hypertension. This study was funded by the Stanford University Cardiovascular Institute. B. Loo and P. Maxim have received funding from RaySearch Laboratories.« less

SU-D-BRD-03: A Gateway for GPU Computing in Cancer Radiotherapy Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jia, X; Folkerts, M; Shi, F

Purpose: Graphics Processing Unit (GPU) has become increasingly important in radiotherapy. However, it is still difficult for general clinical researchers to access GPU codes developed by other researchers, and for developers to objectively benchmark their codes. Moreover, it is quite often to see repeated efforts spent on developing low-quality GPU codes. The goal of this project is to establish an infrastructure for testing GPU codes, cross comparing them, and facilitating code distributions in radiotherapy community. Methods: We developed a system called Gateway for GPU Computing in Cancer Radiotherapy Research (GCR2). A number of GPU codes developed by our group andmore » other developers can be accessed via a web interface. To use the services, researchers first upload their test data or use the standard data provided by our system. Then they can select the GPU device on which the code will be executed. Our system offers all mainstream GPU hardware for code benchmarking purpose. After the code running is complete, the system automatically summarizes and displays the computing results. We also released a SDK to allow the developers to build their own algorithm implementation and submit their binary codes to the system. The submitted code is then systematically benchmarked using a variety of GPU hardware and representative data provided by our system. The developers can also compare their codes with others and generate benchmarking reports. Results: It is found that the developed system is fully functioning. Through a user-friendly web interface, researchers are able to test various GPU codes. Developers also benefit from this platform by comprehensively benchmarking their codes on various GPU platforms and representative clinical data sets. Conclusion: We have developed an open platform allowing the clinical researchers and developers to access the GPUs and GPU codes. This development will facilitate the utilization of GPU in radiation therapy field.« less

Examining Determinants of Radiotherapy Access: Do Cost and Radiotherapy Inconvenience Affect Uptake of Breast-conserving Treatment for Early Breast Cancer?

PubMed

Lam, J; Cook, T; Foster, S; Poon, R; Milross, C; Sundaresan, P

2015-08-01

Radiotherapy utilisation is likely affected by multiple factors pertaining to radiotherapy access. Radiotherapy is an integral component of breast-conserving treatment (BCT) for early breast cancer. We aimed to determine if stepwise improvements in radiotherapy access in regional Australia affected the uptake of BCT and thus radiotherapy. Breast cancer operations in the Central Coast of New South Wales between January 2010 and March 2014 for T1-2N0-1M0 invasive or in situ (≤5 cm) disease in female patients eligible for BCT were examined. BCT uptake was calculated for three 1 year periods: period 1 (local radiotherapy available at cost to user or out of area radiotherapy with travel cost and inconvenience); period 2 (as per period 1 + publicly funded transport and radiotherapy at out of area facilities at no cost to user); period 3 (as per period 1 + publicly funded local radiotherapy at no cost to user). In total, 574 cases met eligibility criteria. BCT declined with increasing distance to publicly funded radiotherapy (P = 0.035). BCT rates for periods 1, 2 and 3 were 63% (113/180), 61% (105/173) and 71% (156/221). There were no statistically significant differences in BCT between periods 1 and 2 in the whole cohort or within age, histology or tumour size subgroups. Overall, there was a 9% increase in BCT in the whole cohort in period 3 compared with periods 1 and 2 (P = 0.031). This increase was statistically significant for women over 70 years (19% increase, P = 0.034), for women with ductal carcinoma in situ (25% increase, P = 0.013) and for women with primary tumours that were ≤10 mm (21% increase, P = 0.016). Improving the affordability of radiotherapy through publicly funded transport and radiotherapy at out of area facilities did not improve BCT uptake in a region where radiotherapy was locally available, albeit at cost to the user. Improving both affordability and convenience through the provision of local publicly funded radiotherapy increased BCT uptake. Service availability and affordability have long been recognised as important determinants of radiotherapy access. Our findings suggest that inconvenience may also influence radiotherapy utilisation. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Very Early Salvage Radiotherapy Improves Distant Metastasis-Free Survival.

PubMed

Abugharib, Ahmed; Jackson, William C; Tumati, Vasu; Dess, Robert T; Lee, Jae Y; Zhao, Shuang G; Soliman, Moaaz; Zumsteg, Zachary S; Mehra, Rohit; Feng, Felix Y; Morgan, Todd M; Desai, Neil; Spratt, Daniel E

2017-03-01

Early salvage radiotherapy following radical prostatectomy for prostate cancer is commonly advocated in place of adjuvant radiotherapy. We aimed to determine the optimal definition of early salvage radiotherapy. We performed a multi-institutional retrospective study of 657 men who underwent salvage radiotherapy between 1986 and 2013. Two comparisons were made to determine the optimal definition of early salvage radiotherapy, including 1) the time from radical prostatectomy to salvage radiotherapy (less than 9, 9 to 21, 22 to 47 or greater than 48 months) and 2) the level of detectable pre-salvage radiotherapy prostate specific antigen (0.01 to 0.2, greater than 0.2 to 0.5 or greater than 0.5 ng/ml). Outcomes included freedom from salvage androgen deprivation therapy, and biochemical relapse-free, distant metastases-free and prostate cancer specific survival. Median followup was 9.8 years. Time from radical prostatectomy to salvage radiotherapy did not correlate with 10-year biochemical relapse-free survival rates (R 2 = 0.18). Increasing pre-salvage radiotherapy prostate specific antigen strongly correlated with biochemical relapse-free survival (R 2 = 0.91). Increasing detectable pre-salvage radiotherapy prostate specific antigen (0.01 to 0.2, greater than 0.2 to 0.5 and greater than 0.5 ng/ml) predicted worse 10-year biochemical relapse-free survival (62%, 44% and 27%), freedom from salvage androgen deprivation therapy (77%, 66% and 49%), distant metastases-free survival (86%, 79% and 66%, each p <0.001) and prostate cancer specific survival (93%, 89% and 80%, respectively, p = 0.001). On multivariable analysis early salvage radiotherapy (prostate specific antigen greater than 0.2 to 0.5 ng/ml) was associated with a twofold increase in biochemical failure, use of salvage androgen deprivation therapy and distant metastases compared to very early salvage radiotherapy (prostate specific antigen 0.01 to 0.2 ng/ml). The duration from radical prostatectomy to salvage radiotherapy is not independently prognostic for outcomes after salvage radiotherapy and it should not be used to define early salvage radiotherapy. Grouping all patients with pre-salvage radiotherapy prostate specific antigen 0.5 ng/ml or less may be inadequate to define early salvage radiotherapy and it has a relevant impact on ongoing and future clinical trials. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Outcome of accelerated radiotherapy alone or accelerated radiotherapy followed by exenteration of the nasal cavity in dogs with intranasal neoplasia: 53 cases (1990-2002).

PubMed

Adams, William M; Bjorling, Dale E; McAnulty, Jonathan E; Green, Eric M; Forrest, Lisa J; Vail, David M

2005-09-15

To compare long-term results of radiotherapy alone versus radiotherapy followed by exenteration of the nasal cavity in dogs with malignant intranasal neoplasia. Retrospective study. 53 dogs with malignant intranasal neoplasia. All dogs underwent radiotherapy consisting of administration of 10 fractions of 4.2 Gy each on consecutive weekdays. For dogs in the surgery group (n=13), follow-up computed tomography was performed, and dogs were scheduled for surgery if persistent or recurrent tumor was seen. Perioperative complications for dogs that underwent surgery included hemorrhage requiring transfusion (2 dogs) and subcutaneous emphysema (8). Rhinitis and osteomyelitis-osteonecrosis occurred significantly more frequently in dogs in the radiotherapy and surgery group (9 and 4 dogs, respectively) than in dogs in the radiotherapy-only group (4 and 3 dogs, respectively). Two- and 3-year survival rates were 44% and 24%, respectively, for dogs in the radiotherapy group and 69% and 58%, respectively, for dogs in the surgery group. Overall median survival time for dogs in the radiotherapy and surgery group (477 months) was significantly longer than time for dogs in the radiotherapy-only group (19.7 months). Results suggest that exenteration of the nasal cavity significantly prolongs survival time in dogs with intranasal neoplasia that have undergone radiotherapy. Exenteration after radiotherapy may increase the risk of chronic complications.

Electron paramagnetic resonance (EPR) dosimetry using lithium formate in radiotherapy: comparison with thermoluminescence (TL) dosimetry using lithium fluoride rods.

PubMed

Vestad, Tor Arne; Malinen, Eirik; Olsen, Dag Rune; Hole, Eli Olaug; Sagstuen, Einar

2004-10-21

Solid-state radiation dosimetry by electron paramagnetic resonance (EPR) spectroscopy and thermoluminescence (TL) was utilized for the determination of absorbed doses in the range of 0.5-2.5 Gy. The dosimeter materials used were lithium formate and lithium fluoride (TLD-100 rods) for EPR dosimetry and TL dosimetry, respectively. 60Co gamma-rays and 4, 6, 10 and 15 MV x-rays were employed. The main objectives were to compare the variation in dosimeter reading of the respective dosimetry systems and to determine the photon energy dependence of the two dosimeter materials. The EPR dosimeter sensitivity was constant over the dose range in question, while the TL sensitivity increased by more than 5% from 0.5 to 2.5 Gy, thus displaying a supralinear dose response. The average relative standard deviation in the dosimeter reading per dose was 3.0% and 1.2% for the EPR and TL procedures, respectively. For EPR dosimeters, the relative standard deviation declined significantly from 4.3% to 1.1% over the dose range in question. The dose-to-water energy response for the megavoltage x-ray beams relative to 60Co gamma-rays was in the range of 0.990-0.979 and 0.984-0.962 for lithium formate and lithium fluoride, respectively. The results show that EPR dosimetry with lithium formate provides dose estimates with a precision comparable to that of TL dosimetry (using lithium fluoride) for doses above 2 Gy, and that lithium formate is slightly less dependent on megavoltage photon beam energy than lithium fluoride.

Electron paramagnetic resonance (EPR) dosimetry using lithium formate in radiotherapy: comparison with thermoluminescence (TL) dosimetry using lithium fluoride rods

NASA Astrophysics Data System (ADS)

Vestad, Tor Arne; Malinen, Eirik; Rune Olsen, Dag; Olaug Hole, Eli; Sagstuen, Einar

2004-10-01

Solid-state radiation dosimetry by electron paramagnetic resonance (EPR) spectroscopy and thermoluminescence (TL) was utilized for the determination of absorbed doses in the range of 0.5-2.5 Gy. The dosimeter materials used were lithium formate and lithium fluoride (TLD-100 rods) for EPR dosimetry and TL dosimetry, respectively. 60Co ggr-rays and 4, 6, 10 and 15 MV x-rays were employed. The main objectives were to compare the variation in dosimeter reading of the respective dosimetry systems and to determine the photon energy dependence of the two dosimeter materials. The EPR dosimeter sensitivity was constant over the dose range in question, while the TL sensitivity increased by more than 5% from 0.5 to 2.5 Gy, thus displaying a supralinear dose response. The average relative standard deviation in the dosimeter reading per dose was 3.0% and 1.2% for the EPR and TL procedures, respectively. For EPR dosimeters, the relative standard deviation declined significantly from 4.3% to 1.1% over the dose range in question. The dose-to-water energy response for the megavoltage x-ray beams relative to 60Co ggr-rays was in the range of 0.990-0.979 and 0.984-0.962 for lithium formate and lithium fluoride, respectively. The results show that EPR dosimetry with lithium formate provides dose estimates with a precision comparable to that of TL dosimetry (using lithium fluoride) for doses above 2 Gy, and that lithium formate is slightly less dependent on megavoltage photon beam energy than lithium fluoride.

Patterns of radiotherapy infrastructure in Japan and in other countries with well-developed radiotherapy infrastructures.

PubMed

Nakamura, Katsumasa; Konishi, Kenta; Komatsu, Tetsuya; Sasaki, Tomonari; Shikama, Naoto

2018-05-01

In high-income countries, the number of radiotherapy machine per population reaches a sufficient level. However, the patterns of infrastructure of radiotherapy in high-income countries are not well known. Among 29 high-income countries with gross national income of $25,000 or more per capita, we selected 23 countries whose total number of newly diagnosed cancer patients in 2012 was reported in the Organisation for Economic Co-operation and Development Health Statistics 2017. The numbers of radiotherapy centers and teletherapy machines in each of these 23 countries were collected using the Dictionary of Radiotherapy Centers database. The number of cancer patients per teletherapy machine was 452.35-1398.22 (median 711.66) with a three-fold variation, whereas the number of cancer patients per radiotherapy center varied even more widely, from 826.16 to 5159.86 (median 2259.83) with a six-fold variation. The average number of teletherapy machines per radiotherapy center also ranged widely, from 1.24 to 8.29 (median 3.11) with a seven-fold variation. The number of teletherapy machines in each country was almost proportional to that of cancer patients, and the number of teletherapy machines per radiotherapy center was inversely related to the number of radiotherapy centers per cancer patients. The number of teletherapy machines per radiotherapy center in Japan was 1.24, the most fragmented among the high-income countries. The percentage of large radiotherapy centers having three or more teletherapy machines in Japan was the smallest among 23 high-income countries. Optimization of the radiotherapy infrastructure in Japan should be carefully considered.

Effect of radiotherapy after breast-conserving surgery in older patients with early breast cancer and breast ductal carcinoma in situ: a meta-analysis

PubMed Central

Chen, Wen-jun; Zhang, Xi; Wu, Cong-cong; Zhang, Chao-ying; Sun, Shuang-shuang; Wu, Jian

2017-01-01

Background There are no consistent agreements on whether radiotherapy after breast-conserving surgery (BCS) could provide local control and survival benefit for older patients with early breast cancer or breast ductal carcinoma in situ (DCIS). The present study aimed to evaluate the efficacy of radiotherapy after BCS in older patients with early breast cancer or DCIS. Results Radiotherapy could reduce the risk of local relapse in older patients with early breast cancer. The 5-year AR of local relapse was 2.2% and 6.2% for radiotherapy and non-radiotherapy group, respectively, with low 5-year ARD of 4.0% and high NNT of 25. The 10-year AR of local relapse was 5.3% and 10.5% for radiotherapy and non-radiotherapy group, respectively, with the 10-year ARD of 5.2% and NNT of 20. However, radiotherapy could not improve survival benefits, including overall survival, cancer-specific survival, breast-cancer-specific survival, and distant relapse. Moreover, radiotherapy could reduce the risk of ipsilateral breast events in older patients with DCIS. Materials and Methods PubMed and Embase database were searched for relevant studies. Hazard ratios (HRs), risk ratios (RRs), absolute risk (AR), absolute risk difference (ARD), and number needed to treat (NNT) were used as effect measures to evaluate the efficacy of radiotherapy in older patients. Conclusions Our study indicates that radiotherapy could slightly reduce the risk of local relapse in older patients with favorable early breast cancer. However, radiotherapy cannot translate into significant survival benefits. PMID:28415667

Barriers to radiotherapy access at the University College Hospital in Ibadan, Nigeria.

PubMed

Anakwenze, Chidinma P; Ntekim, Atara; Trock, Bruce; Uwadiae, Iyobosa B; Page, Brandi R

2017-08-01

Nigeria has the biggest gap between radiotherapy availability and need, with one machine per 19.4 million people, compared to one machine per 250,000 people in high-income countries. This study aims to identify its patient-level barriers to radiotherapy access. This was a cross sectional study consisting of patient questionnaires ( n  = 50) conducted in January 2016 to assess patient demographics, types of cancers seen, barriers to receiving radiotherapy, health beliefs and practices, and factors leading to treatment delay. Eighty percent of patients could not afford radiotherapy without financial assistance and only 6% of the patients had federal insurance, which did not cover radiotherapy services. Of the patients who had completed radiotherapy treatment, 91.3% had experienced treatment delay or often cancellation due to healthcare worker strike, power failure, machine breakdown, or prolonged wait time. The timeliness of a patient's radiotherapy care correlated with their employment status and distance from radiotherapy center ( p  < 0.05). Barriers to care at a radiotherapy center in a low- and middle-income country (LMIC) have previously not been well characterized. These findings can be used to inform efforts to expand the availability of radiotherapy and improve current treatment capacity in Nigeria and in other LMICs.

3D polymer gel dosimetry using a 3D (DESS) and a 2D MultiEcho SE (MESE) sequence

NASA Astrophysics Data System (ADS)

Maris, Thomas G.; Pappas, Evangelos; Karolemeas, Kostantinos; Papadakis, Antonios E.; Zacharopoulou, Fotini; Papanikolaou, Nickolas; Gourtsoyiannis, Nicholas

2006-12-01

The utilization of 3D techniques in Magnetic Resonance Imaging data aquisition and post-processing analysis is a prerequisite especially when modern radiotherapy techniques (conformal RT, IMRT, Stereotactic RT) are to be used. The aim of this work is to compare a 3D Double Echo Steady State (DESS) and a 2D Multiple Echo Spin Echo (MESE) sequence in 3D MRI radiation dosimetry using two different MRI scanners and utilising N-VInylPyrrolidone (VIPAR) based polymer gels.

Melatonin uses in oncology: breast cancer prevention and reduction of the side effects of chemotherapy and radiation.

PubMed

Sanchez-Barcelo, Emilio J; Mediavilla, Maria D; Alonso-Gonzalez, Carolina; Reiter, Russel J

2012-06-01

The possible oncostatic properties of melatonin on different types of neoplasias have been studied especially in hormone-dependent adenocarcinomas. Despite the promising results of these experimental investigations, the use of melatonin in breast cancer treatment in humans is still uncommon. This article reviews the usefulness of this indoleamine for specific aspects of breast cancer management, particularly in reference to melatonin's antiestrogenic and antioxidant properties: i) treatments oriented to breast cancer prevention, especially when the risk factors are obesity, steroid hormone treatment or chronodisruption by exposure to light at night (LAN); ii) treatment of the side effects associated with chemo- or radiotherapy. The clinical utility of melatonin depends on the appropriate identification of its actions. Because of its SERM (selective estrogen receptor modulators) and SEEM (selective estrogen enzyme modulators) properties, and its virtual absence of contraindications, melatonin could be an excellent adjuvant with the drugs currently used for breast cancer prevention (antiestrogens and antiaromatases). The antioxidant actions also make melatonin a suitable treatment to reduce oxidative stress associated with chemotherapy, especially with anthracyclines, and radiotherapy.

Utility of the omentum in sacral reconstruction following total sacrectomy due to recurrent and irradiated giant cell tumour of the spine

PubMed Central

Unal, Cigdem; Eren, Guler Gamze; Isil, Eda; Alponat, Ahmet; Sarlak, Ahmet

2012-01-01

Reconstruction of the lumbosacral region after surgical excision of irradiated and recurrent spinal giant cell tumours remains a challenging problem. In this case report, we describe the use of the pedicled omentum flap in reconstruction of an irradiated and infected wide sacral defect of a 19-year-old male patient. The patient had radiotherapy and subsequent wide surgical resection after recurrence of the tumour. A myocutaneous flap from the gluteal area had failed previously. Local flap options could not be used because of the recent radiotherapy to the gluteal area. Since the patient had a laparotomy for tumour resection and a colostomy, abdominal muscles were not considered reliable for reconstructive procedures. A pedicled omentum flap was chosen as a reconstructive option because of its rich blood supply, large surface area, and angiogenic capacity. This report aims to describe the use of the pedicled omentum flap for reconstruction of the lumbosacral area following surgical resection of a spinal tumour, when gluteal and abdominal flap options for reconstruction are jeopardised. PMID:22754172

Utility of the omentum in sacral reconstruction following total sacrectomy due to recurrent and irradiated giant cell tumour of the spine.

PubMed

Unal, Cigdem; Eren, Guler Gamze; Isil, Eda; Alponat, Ahmet; Sarlak, Ahmet

2012-01-01

Reconstruction of the lumbosacral region after surgical excision of irradiated and recurrent spinal giant cell tumours remains a challenging problem. In this case report, we describe the use of the pedicled omentum flap in reconstruction of an irradiated and infected wide sacral defect of a 19-year-old male patient. The patient had radiotherapy and subsequent wide surgical resection after recurrence of the tumour. A myocutaneous flap from the gluteal area had failed previously. Local flap options could not be used because of the recent radiotherapy to the gluteal area. Since the patient had a laparotomy for tumour resection and a colostomy, abdominal muscles were not considered reliable for reconstructive procedures. A pedicled omentum flap was chosen as a reconstructive option because of its rich blood supply, large surface area, and angiogenic capacity. This report aims to describe the use of the pedicled omentum flap for reconstruction of the lumbosacral area following surgical resection of a spinal tumour, when gluteal and abdominal flap options for reconstruction are jeopardised.

Lung Cancer Brain Metastases.

PubMed

Goldberg, Sarah B; Contessa, Joseph N; Omay, Sacit B; Chiang, Veronica

2015-01-01

Brain metastases are common among patients with lung cancer and have been associated with significant morbidity and limited survival. However, the treatment of brain metastases has evolved as the field has advanced in terms of central nervous system imaging, surgical technique, and radiotherapy technology. This has allowed patients to receive improved treatment with less toxicity and more durable benefit. In addition, there have been significant advances in systemic therapy for lung cancer in recent years, and several treatments including chemotherapy, targeted therapy, and immunotherapy exhibit activity in the central nervous system. Utilizing systemic therapy for treating brain metastases can avoid or delay local therapy and often allows patients to receive effective treatment for both intracranial and extracranial disease. Determining the appropriate treatment for patients with lung cancer brain metastases therefore requires a clear understanding of intracranial disease burden, tumor histology, molecular characteristics, and overall cancer prognosis. This review provides updates on the current state of surgery and radiotherapy for the treatment of brain metastases, as well as an overview of systemic therapy options that may be effective in select patients with intracranial metastases from lung cancer.

Cancer Deaths due to Lack of Universal Access to Radiotherapy in the Brazilian Public Health System.

PubMed

Mendez, L C; Moraes, F Y; Fernandes, G Dos S; Weltman, E

2018-01-01

Radiotherapy plays a fundamental role in the treatment of cancer. Currently, the Brazilian public health system cannot match the national radiotherapy demand and many patients requiring radiotherapy are never exposed to this treatment. This study estimated the number of preventable deaths in the public health system if access to radiotherapy was universal. Incidence rates for the year 2016 provided by Instituto Nacional de Cancer were used in this analysis. The number of untreated patients requiring radiotherapy was obtained through the difference between the total number of patients requiring radiotherapy and the total amount of delivered radiotherapy treatments in the public health system. The number of deaths for the three most common cancers in each gender due to radiotherapy shortage was calculated. Initially, the total number of patients per cancer type was divided in stages using Brazilian epidemiological data. Subsequently, previously published tree arm diagrams were used to define the rate of patients requiring radiotherapy in each specific clinical setting. Finally, the clinical benefit of radiotherapy in overall survival was extracted from studies with level 1 evidence. Over 596 000 cancer cases were expected in Brazil in 2016. The public health system covers more than 75% of the Brazilian population and an estimated 111 432 patients who required radiotherapy in 2016 did not receive this treatment. Breast, colorectal and cervix cancers are the most frequent malignant tumours in women and prostate, lung and colorectal in men. The number of deaths due to a radiotherapy shortage in the year 2016 for these types of cancer were: (i) breast: 1011 deaths in 10 years; (ii) cervix: 2006 deaths in 2 years; (iii) lung: 1206 deaths in 2 years; (iv) prostate, intermediate risk: 562 deaths in 13 years; high risk: 298 deaths in 10 years; (v) colorectal: 0 deaths, as radiotherapy has no proven benefit in overall survival. Thousands of cancer patients requiring radiotherapy do not have access to this treatment in the Brazilian public health system. The shortage of radiotherapy has a significant detrimental effect on cancer survival; over 5000 deaths would probably be prevented in the most common cancer types if radiotherapy access was universal. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Implementation of an intraoperative electron radiotherapy in vivo dosimetry program.

PubMed

López-Tarjuelo, Juan; Morillo-Macías, Virginia; Bouché-Babiloni, Ana; Boldó-Roda, Enrique; Lozoya-Albacar, Rafael; Ferrer-Albiach, Carlos

2016-03-15

Intraoperative electron radiotherapy (IOERT) is a highly selective radiotherapy technique which aims to treat restricted anatomic volumes during oncological surgery and is now the subject of intense re-evaluation. In vivo dosimetry has been recommended for IOERT and has been identified as a risk-reduction intervention in the context of an IOERT risk analysis. Despite reports of fruitful experiences, information about in vivo dosimetry in intraoperative radiotherapy is somewhat scarce. Therefore, the aim of this paper is to report our experience in developing a program of in vivo dosimetry for IOERT, from both multidisciplinary and practical approaches, in a consistent patient series. We also report several current weaknesses. Reinforced TN-502RDM-H mobile metal oxide semiconductor field effect transistors (MOSFETs) and Gafchromic MD-55-2 films were used as a redundant in vivo treatment verification system with an Elekta Precise fixed linear accelerator for calibrations and treatments. In vivo dosimetry was performed in 45 patients in cases involving primary tumors or relapses. The most frequent primary tumors were breast (37 %) and colorectal (29 %), and local recurrences among relapses was 83 %. We made 50 attempts to measure with MOSFETs and 48 attempts to measure with films in the treatment zones. The surgical team placed both detectors with supervision from the radiation oncologist and following their instructions. The program was considered an overall success by the different professionals involved. The absorbed doses measured with MOSFETs and films were 93.8 ± 6.7 % and 97.9 ± 9.0 % (mean ± SD) respectively using a scale in which 90 % is the prescribed dose and 100 % is the maximum absorbed dose delivered by the beam. However, in 10 % of cases we experienced dosimetric problems due to detector misalignment, a situation which might be avoided with additional checks. The useful MOSFET lifetime length and the film sterilization procedure should also be controlled. It is feasible to establish an in vivo dosimetry program for a wide set of locations treated with IOERT using a multidisciplinary approach according to the skills of the professionals present and the detectors used; oncological surgeons' commitment is key to success in this context. Films are more unstable and show higher uncertainty than MOSFETs but are cheaper and are useful and convenient if real-time treatment monitoring is not necessary.

Cost of New Technologies in Prostate Cancer Treatment: Systematic Review of Costs and Cost Effectiveness of Robotic-assisted Laparoscopic Prostatectomy, Intensity-modulated Radiotherapy, and Proton Beam Therapy.

PubMed

Schroeck, Florian Rudolf; Jacobs, Bruce L; Bhayani, Sam B; Nguyen, Paul L; Penson, David; Hu, Jim

2017-11-01

Some of the high costs of robot-assisted radical prostatectomy (RARP), intensity-modulated radiotherapy (IMRT), and proton beam therapy may be offset by better outcomes or less resource use during the treatment episode. To systematically review the literature to identify the key economic trade-offs implicit in a particular treatment choice for prostate cancer. We systematically reviewed the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement and protocol. We searched Medline, Embase, and Web of Science for articles published between January 2001 and July 2016, which compared the treatment costs of RARP, IMRT, or proton beam therapy to the standard treatment. We identified 37, nine, and three studies, respectively. RARP is costlier than radical retropubic prostatectomy for hospitals and payers. However, RARP has the potential for a moderate cost advantage for payers and society over a longer time horizon when optimal cancer and quality-of-life outcomes are achieved. IMRT is more expensive from a payer's perspective compared with three-dimensional conformal radiotherapy, but also more cost effective when defined by an incremental cost effectiveness ratio <$50 000 per quality-adjusted life year. Proton beam therapy is costlier than IMRT and its cost effectiveness remains unclear given the limited comparative data on outcomes. Using the Grades of Recommendation, Assessment, Development and Evaluation approach, the quality of evidence was low for RARP and IMRT, and very low for proton beam therapy. Treatment with new versus traditional technologies is costlier. However, given the low quality of evidence and the inconsistencies across studies, the precise difference in costs remains unclear. Attempts to estimate whether this increased cost is worth the expense are hampered by the uncertainty surrounding improvements in outcomes, such as cancer control and side effects of treatment. If the new technologies can consistently achieve better outcomes, then they may be cost effective. We review the cost and cost effectiveness of robot-assisted radical prostatectomy, intensity-modulated radiotherapy, and proton beam therapy in prostate cancer treatment. These technologies are costlier than their traditional counterparts. It remains unclear whether their use is associated with improved cure and reduced morbidity, and whether the increased cost is worth the expense. Published by Elsevier B.V.

Post-radiotherapy hypothyroidism in dogs treated for thyroid carcinomas.

PubMed

Amores-Fuster, I; Cripps, P; Blackwood, L

2017-03-01

Hypothyroidism is a common adverse event after head and neck radiotherapy in human medicine, but uncommonly reported in canine patients. Records of 21 dogs with histologically or cytologically confirmed thyroid carcinoma receiving definitive or hypofractionated radiotherapy were reviewed. Nine cases received 48 Gy in 12 fractions, 10 received 36 Gy in 4 fractions and 2 received 32 Gy in 4 fractions. Seventeen cases had radiotherapy in a post-operative setting. Ten cases developed hypothyroidism (47.6%) after radiotherapy. The development of hypothyroidism was not associated with the radiotherapy protocol used. Median time to diagnosis of hypothyroidism was 6 months (range, 1-13 months). Hypothyroidism is a common side effect following radiotherapy for thyroid carcinomas. Monitoring of thyroid function following radiotherapy is recommended. No specific risk factors have been identified. © 2015 John Wiley & Sons Ltd.

Precision Distances with the Tip of the Red Giant Branch Method

NASA Astrophysics Data System (ADS)

Beaton, Rachael Lynn; Carnegie-Chicago Hubble Program Team

2018-01-01

The Carnegie-Chicago Hubble Program aims to construct a distance ladder that utilizes old stellar populations in the outskirts of galaxies to produce a high precision measurement of the Hubble Constant that is independent of Cepheids. The CCHP uses the tip of the red giant branch (TRGB) method, which is a statistical measurement technique that utilizes the termination of the red giant branch. Two innovations combine to make the TRGB a competitive route to the Hubble Constant (i) the large-scale measurement of trigonometric parallax by the Gaia mission and (ii) the development of both precise and accurate means of determining the TRGB in both nearby (~1 Mpc) and distant (~20 Mpc) galaxies. Here I will summarize our progress in developing these standardized techniques, focusing on both our edge-detection algorithm and our field selection strategy. Using these methods, the CCHP has determined equally precise (~2%) distances to galaxies in the Local Group (< 1 Mpc) and across the Local Volume (< 20 Mpc). The TRGB is, thus, an incredibly powerful and straightforward means to determine distances to galaxies of any Hubble Type and, thus, has enormous potential for putting any number of astrophyiscal phenomena on absolute units.

Method for making precisely configured flakes useful in optical devices

DOEpatents

Trajkovska-Petkoska, Anka [Rochester, NY; Jacobs, Stephen D [Pittsford, NY; Kosc, Tanya Z [Rochester, NY; Marshall, Kenneth L [Rochester, NY

2007-07-03

Precisely configured, especially of geometric shape, flakes of liquid crystal material are made using a mechanically flexible polymer mold with wells having shapes which are precisely configured by making the mold with a photolithographically manufactured or laser printed master. The polymer liquid crystal is poured into the wells in the flexible mold. When the liquid crystal material has solidified, the flexible mold is bent and the flakes are released and collected for use in making an electrooptical cell utilizing the liquid crystal flakes as the active element therein.

Numerical Roll Reversal Predictor Corrector Aerocapture and Precision Landing Guidance Algorithms for the Mars Surveyor Program 2001 Missions

NASA Technical Reports Server (NTRS)

Powell, Richard W.

1998-01-01

This paper describes the development and evaluation of a numerical roll reversal predictor-corrector guidance algorithm for the atmospheric flight portion of the Mars Surveyor Program 2001 Orbiter and Lander missions. The Lander mission utilizes direct entry and has a demanding requirement to deploy its parachute within 10 km of the target deployment point. The Orbiter mission utilizes aerocapture to achieve a precise captured orbit with a single atmospheric pass. Detailed descriptions of these predictor-corrector algorithms are given. Also, results of three and six degree-of-freedom Monte Carlo simulations which include navigation, aerodynamics, mass properties and atmospheric density uncertainties are presented.

[Timing of Brain Radiation Therapy Impacts Outcomes in Patients with 
Non-small Cell Lung Cancer Who Develop Brain Metastases].

PubMed

Wang, Yang; Fang, Jian; Nie, Jun; Dai, Ling; Hu, Weiheng; Zhang, Jie; Ma, Xiangjuan; Han, Jindi; Chen, Xiaoling; Tian, Guangming; Wu, Di; Han, Sen; Long, Jieran

2016-08-20

Radiotherapy combined with chemotherapy or molecular targeted therapy remains the standard of treatment for brain metastases from non-small cell lung cancer (NSCLC). The aim of this study is to determine if the deferral of brain radiotherapy impacts patient outcomes. Between May 2003 and December 2015, a total of 198 patients with brain metastases from NSCLC who received both brain radiotherapy and systemic therapy (chemotherapy or targeted therapy) were identified. The rate of grade 3-4 adverse reactions related to chemotherapy and radiotherapy had no significant difference between two groups. 127 patients received concurrent brain radiotherapy and systemic therapy, and 71 patients received deferred brain radiotherapy after at least two cycles of chemotherapy or targeted therapy. Disease specific-graded prognostic assessment was similar in early radiotherapy group and deferred radiotherapy group. Median overall survival (OS) was longer in early radiotherapy group compared to deferred radiotherapy group (17.9 months vs 12.6 months; P=0.038). Progression free survival (PFS) was also improved in patients receiving early radiotherapy compared to those receiving deferred radiotherapy (4.0 months vs 3.0 months; P<0.01). Receiving tyrosine kinase inhibitor (TKI) therapy after the diagnosis of brain metastases as any line therapy improved the OS (20.0 months vs 10.7 months; P<0.01), whereas receiving TKI as first line therapy did not (17.9 months vs 15.2 months; P=0.289). Our study suggests that the use of deferred brain radiotherapy may resulted in inferior OS in patients with NSCLC who develop brain metastases. A prospective multi-central randomized study is imminently needed.

Radiotherapy access in Belgium: How far are we from evidence-based utilisation?

PubMed

Lievens, Y; De Schutter, H; Stellamans, K; Rosskamp, M; Van Eycken, L

2017-10-01

Underutilisation of radiotherapy has been observed worldwide. To evaluate the current situation in Belgium, optimal utilisation proportions (OUPs) adopted from the European SocieTy for Radiotherapy and Oncology - Health Economics in Radiation Oncology (ESTRO-HERO) project were compared to actual utilisation proportions (AUPs) and with radiotherapy advised during the multidisciplinary cancer team (MDT) meetings. In addition, the impact of independent variables was analysed. AUPs and advised radiotherapy were calculated overall and by cancer type for 110,810 unique cancer diagnoses in 2009-2010. Radiotherapy utilisation was derived from reimbursement data and distinguished between palliative and curative intent external beam radiotherapy (EBRT) and/or brachytherapy (BT). Sensitivity analyses regarding the influence of the follow-up period, the survival length and patient's age were performed. Advised radiotherapy was calculated based on broad treatment categories as reported at MDT meetings. The overall AUP of 37% (39% including BT) was lower than the OUP of 53%, but in line with advised radiotherapy (35%). Large variations by tumour type were observed: in some tumours (e.g. lung and prostate cancer) AUP was considerably lower than OUP, whereas in others there was reasonable concordance (e.g. breast and rectal cancer). Overall, 84% of treatments started within 9 months following diagnosis. Survival time influenced AUP in a cancer type-dependent way. Elderly patients received less radiotherapy. Although the actually delivered radiotherapy in Belgium aligns well to MDT advices, it is lower than the evidence-based optimum. Further analysis of potential barriers is needed for radiotherapy forecasting and planning, and in order to promote adequate access to radiotherapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

New Agents, Emerging Late Effects, and the Development of Precision Survivorship.

PubMed

Chow, Eric J; Antal, Zoltan; Constine, Louis S; Gardner, Rebecca; Wallace, W Hamish; Weil, Brent R; Yeh, Jennifer M; Fox, Elizabeth

2018-06-06

Incremental improvements in the treatment of children and adolescents with cancer have led to 5-year survival rates reaching nearly 85%. In the past decade, impressive progress has been made in understanding the biology of many pediatric cancers. With that understanding, multiple new agents have become available that offer the promise of more-effective and less-toxic treatment. These include agents that target various cell surface antigens and engage the adaptive immune system, as well as those that interfere with key signaling pathways involved in tumor development and growth. For local control, surgery and radiation techniques also have evolved, becoming less invasive or featuring new techniques and particles that more precisely target the tumor and limit the dose to normal tissue. Nevertheless, targeted agents, like conventional chemotherapy, radiotherapy, and surgery, may have off-target effects and deserve long-term follow-up of their safety and efficacy. These include injury to the endocrine, cardiovascular, and immunologic systems. New radiation and surgical techniques that theoretically reduce morbidity and improve long-term quality of life must also be validated with actual patient outcomes. Finally, with advances in genomics, information on host susceptibility to late effects is beginning to emerge. Such knowledge, coupled with improved metrics that better describe the spectrum of potential late effects across the entire lifespan, can lead to the development of decision models that project the potential long-term health outcomes associated with various treatment and follow-up strategies. These developments will help extend the current focus on precision medicine to precision survivorship, where clinicians, patients, and families will have a better grasp of the potential risks, benefits, and tradeoffs associated with the growing number of cancer treatment options.

Exploring the variation of oral microbiota in supragingival plaque during and after head-and-neck radiotherapy using pyrosequencing.

PubMed

Gao, Li; Hu, Yuejian; Wang, Yuxia; Jiang, Wenxin; He, Zhiyan; Zhu, Cailian; Ma, Rui; Huang, Zhengwei

2015-09-01

The aim of this article was to study the variation in oral microflora of the subgingival plaque during and after radiotherapy. During and after radiotherapy, microbial samples were collected at seven time points (early stage, medium stage, and later stage of radiotherapy, and 1 month, 3 months, 6 months, and 1 year after radiotherapy) in three subjects for a total of 21 samples. Polymerase chain reaction (PCR) amplification was carried out on the 16S rDNA hypervariable V1-V3 region, and then the PCR products were determined by high-throughput pyrosequencing. The rarefaction curve indicating the richness of the microflora demonstrated that the number of operational taxonomic units (OTUs) was in decline from the early stage of radiotherapy to the time point 1 month after radiotherapy and then trended upward. The Shannon diversity index declined during radiotherapy (ranging from 4.59 to 3.73), and generally rose after radiotherapy, with the lowest value of 3.5 (1 month after radiotherapy) and highest value of 4.75 (6 months after radiotherapy). A total of 120 genera were found; five genera (Actinomyces, Veillonella, Prevotella, Streptococcus, Campylobacter) were found in all subjects across all time points. The richness and diversity of oral ecology decreased with increased radiation dose, and it was gradually restored with time. Copyright © 2015 Elsevier Ltd. All rights reserved.

Adjuvant radiotherapy after breast conserving surgery - a comparative effectiveness research study.

PubMed

Corradini, Stefanie; Niyazi, Maximilian; Niemoeller, Olivier M; Li, Minglun; Roeder, Falk; Eckel, Renate; Schubert-Fritschle, Gabriele; Scheithauer, Heike R; Harbeck, Nadia; Engel, Jutta; Belka, Claus

2015-01-01

The purpose of this retrospective outcome study was to validate the effectiveness of postoperative radiotherapy in breast conserving therapy (BCT) and to evaluate possible causes for omission of radiotherapy after breast conserving surgery (BCS) in a non-trial population. Data were provided by the population-based Munich Cancer Registry. The study included epidemiological data of 30.811 patients diagnosed with breast cancer from 1998 to 2012. The effect of omitting radiotherapy was analysed using Kaplan-Meier-estimates and Cox proportional hazard regression. Variables predicting omission of radiotherapy were analysed using multivariate logistic regression. Use of postoperative radiotherapy after BCS was associated with significant improvements in local control and survival. 10-year loco-regional recurrence-free-survival was 90.8% with postoperative radiotherapy vs. 77.6% with surgery alone (p<0.001). 10-year overall survival rates were 55.2% with surgery alone vs. 82.2% following postoperative radiotherapy (p<0.001). Variables predicting omission of postoperative radiotherapy included advanced age (women ⩾80 years; OR: 0.082; 95% CI: 0.071-0.094, p<0.001). This study shows a decrease in local control and a survival disadvantage if postoperative radiotherapy after breast conserving surgery is omitted in an unselected cohort of primary breast cancer patients. Due to its epidemiological nature, it cannot answer the question in whom postoperative radiotherapy can be safely omitted. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Proton beam radiotherapy in the management of uveal melanoma: Clinical experience in Scotland

PubMed Central

Aziz, Samir; Taylor, Alex; McConnachie, Andrzej; Kacperek, Alex; Kemp, Ewan

2009-01-01

Aim: To evaluate proton-beam radiotherapy (PBRT) in the management of uveal melanoma in Scotland. Methods: A retrospective review was undertaken on all patients receiving PBRT for uveal melanoma (1994–2005). Data obtained included: gender, past ocular/medical history, age, presenting complaint(s), diagnosis, laterality, tumor location/ultrasound characteristics, visual acuity (VA) and intraocular pressure. At post-treatment reviews (3, 6, 12, and 24 months), the following data was obtained: VA, intraocular pressure, tumor appearance and ultrasound characteristics. Mean follow up was 38.8 months. Results: Seventy-six patients were included. Mean age was 64 years; male to female ratio was 1.1:1. Ninety-seven percent demonstrated initial treatment response; 87% had successful control of tumor growth. Mean pre-treatment tumor height was 6.2 mm v.s. 4.8 mm post-irradiation (p < 0.001). Pre-irradiation VA was <3/60 in 18.5% compared with 74% post-irradiation (p < 0.0001). There was a statistically significant association between adverse events (enucleation, metastasis) and greater maximal basal tumor diameter. Eighteen eyes were enucleated. The median survival time was estimated to be 54 months. Conclusion: In our experience, PBRT is a precise, reliable and effective treatment in the management of large, and previously treated uveal melanomas. It prevents enucleation in the majority at short term follow-up. PMID:19668544

Eye tracking and gating system for proton therapy of orbital tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Dongho; Yoo, Seung Hoon; Moon, Sung Ho

2012-07-15

Purpose: A new motion-based gated proton therapy for the treatment of orbital tumors using real-time eye-tracking system was designed and evaluated. Methods: We developed our system by image-pattern matching, using a normalized cross-correlation technique with LabVIEW 8.6 and Vision Assistant 8.6 (National Instruments, Austin, TX). To measure the pixel spacing of an image consistently, four different calibration modes such as the point-detection, the edge-detection, the line-measurement, and the manual measurement mode were suggested and used. After these methods were applied to proton therapy, gating was performed, and radiation dose distributions were evaluated. Results: Moving phantom verification measurements resulted in errorsmore » of less than 0.1 mm for given ranges of translation. Dosimetric evaluation of the beam-gating system versus nongated treatment delivery with a moving phantom shows that while there was only 0.83 mm growth in lateral penumbra for gated radiotherapy, there was 4.95 mm growth in lateral penumbra in case of nongated exposure. The analysis from clinical results suggests that the average of eye movements depends distinctively on each patient by showing 0.44 mm, 0.45 mm, and 0.86 mm for three patients, respectively. Conclusions: The developed automatic eye-tracking based beam-gating system enabled us to perform high-precision proton radiotherapy of orbital tumors.« less

Lowering whole-body radiation doses in pediatric intensity-modulated radiotherapy through the use of unflattened photon beams.

PubMed

Cashmore, Jason; Ramtohul, Mark; Ford, Dan

2011-07-15

Intensity modulated radiotherapy (IMRT) has been linked with an increased risk of secondary cancer induction due to the extra leakage radiation associated with delivery of these techniques. Removal of the flattening filter offers a simple way of reducing head leakage, and it may be possible to generate equivalent IMRT plans and to deliver these on a standard linear accelerator operating in unflattened mode. An Elekta Precise linear accelerator has been commissioned to operate in both conventional and unflattened modes (energy matched at 6 MV) and a direct comparison made between the treatment planning and delivery of pediatric intracranial treatments using both approaches. These plans have been evaluated and delivered to an anthropomorphic phantom. Plans generated in unflattened mode are clinically identical to those for conventional IMRT but can be delivered with greatly reduced leakage radiation. Measurements in an anthropomorphic phantom at clinically relevant positions including the thyroid, lung, ovaries, and testes show an average reduction in peripheral doses of 23.7%, 29.9%, 64.9%, and 70.0%, respectively, for identical plan delivery compared to conventional IMRT. IMRT delivery in unflattened mode removes an unwanted and unnecessary source of scatter from the treatment head and lowers leakage doses by up to 70%, thereby reducing the risk of radiation-induced second cancers. Removal of the flattening filter is recommended for IMRT treatments. Copyright © 2011 Elsevier Inc. All rights reserved.

A novel imaging technique for fusion of high-quality immobilised MR images of the head and neck with CT scans for radiotherapy target delineation.

PubMed

Webster, G J; Kilgallon, J E; Ho, K F; Rowbottom, C G; Slevin, N J; Mackay, R I

2009-06-01

Uncertainty and inconsistency are observed in target volume delineation in the head and neck for radiotherapy treatment planning based only on CT imaging. Alternative modalities such as MRI have previously been incorporated into the delineation process to provide additional anatomical information. This work aims to improve on previous studies by combining good image quality with precise patient immobilisation in order to maintain patient position between scans. MR images were acquired using quadrature coils placed over the head and neck while the patient was immobilised in the treatment position using a five-point thermoplastic shell. The MR image and CT images were automatically fused in the Pinnacle treatment planning system using Syntegra software. Image quality, distortion and accuracy of the image registration using patient anatomy were evaluated. Image quality was found to be superior to that acquired using the body coil, while distortion was < 1.0 mm to a radius of 8.7 cm from the scan centre. Image registration accuracy was found to be 2.2 mm (+/- 0.9 mm) and < 3.0 degrees (n = 6). A novel MRI technique that combines good image quality with patient immobilization has been developed and is now in clinical use. The scan duration of approximately 15 min has been well tolerated by all patients.

Optimisation of the imaging and dosimetric characteristics of an electronic portal imaging device employing plastic scintillating fibres using Monte Carlo simulations.

PubMed

Blake, S J; McNamara, A L; Vial, P; Holloway, L; Kuncic, Z

2014-11-21

A Monte Carlo model of a novel electronic portal imaging device (EPID) has been developed using Geant4 and its performance for imaging and dosimetry applications in radiotherapy has been characterised. The EPID geometry is based on a physical prototype under ongoing investigation and comprises an array of plastic scintillating fibres in place of the metal plate/phosphor screen in standard EPIDs. Geometrical and optical transport parameters were varied to investigate their impact on imaging and dosimetry performance. Detection efficiency was most sensitive to variations in fibre length, achieving a peak value of 36% at 50 mm using 400 keV x-rays for the lengths considered. Increases in efficiency for longer fibres were partially offset by reductions in sensitivity. Removing the extra-mural absorber surrounding individual fibres severely decreased the modulation transfer function (MTF), highlighting its importance in maximising spatial resolution. Field size response and relative dose profile simulations demonstrated a water-equivalent dose response and thus the prototype's suitability for dosimetry applications. Element-to-element mismatch between scintillating fibres and underlying photodiode pixels resulted in a reduced MTF for high spatial frequencies and quasi-periodic variations in dose profile response. This effect is eliminated when fibres are precisely matched to underlying pixels. Simulations strongly suggest that with further optimisation, this prototype EPID may be capable of simultaneous imaging and dosimetry in radiotherapy.

Breast Cancer Patients’ Experience of External-Beam Radiotherapy

PubMed Central

Schnur, Julie B.; Ouellette, Suzanne C.; Bovbjerg, Dana H.; Montgomery, Guy H.

2013-01-01

Radiotherapy is a critical component of treatment for the majority of women with breast cancer, particularly those who receive breast conserving surgery. Although medically beneficial, radiotherapy can take a physical and psychological toll on patients. However, little is known about the specific thoughts and feelings experienced by women undergoing breast cancer radiotherapy. Therefore, the study aim was to use qualitative research methods to develop an understanding of these thoughts and feelings based on 180 diary entries, completed during radiotherapy by 15 women with Stage 0-III breast cancer. Thematic analysis identified four primary participant concerns: (a) a preoccupation with time; (b) fantasies (both optimistic and pessimistic) about life following radiotherapy; (c) the toll their side-effect experience takes on their self-esteem; and (d) feeling mystified by radiotherapy. These themes are consistent with previous literature on illness and identity. These findings have implications for the treatment and care of women undergoing breast cancer radiotherapy. PMID:19380502

Development and validation of a cancer-specific swallowing assessment tool: MASA-C.

PubMed

Carnaby, Giselle D; Crary, Michael A

2014-03-01

We present data from a sample of patients receiving radiotherapy for head/neck cancer to define and measure the validity of a new clinical assessment measure for swallowing. Fifty-eight patients undergoing radiotherapy (±chemotherapy) for head/neck cancer (HNC) supported the development of a physiology-based assessment tool of swallowing (Mann Assessment of Swallowing Ability--Cancer: MASA-C) administered at two time points (baseline and following radiotherapy treatment). The new exam was evaluated for internal consistency of items using Cronbach's alpha. Reliability of measurement was evaluated with intraclass correlation (ICC) and the Kappa statistic between two independent raters. Concurrent validity was established through comparison with the original MASA examination and against the referent standard videofluoroscopic swallowing examination (VFE). Sensitivity, specificity, and likelihood ratios along with 95 % confidence intervals (CIs) were derived for comparison of the two evaluation forms (MASA vs. MASA-C). Accuracy of diagnostic precision was displayed using receiver operator characteristic curves. The new MASA-C tool demonstrated superior validity to the original MASA examination applied to a HNC population. In comparison to the VFE referent exam, the MASA-C revealed strong sensitivity and specificity (Se 83, Sp 96), predictive values (positive predictive value (PPV) 0.95, negative predictive value (NPV) 0.86), and likelihood ratios (21.6). In addition, it demonstrated good reliability (ICC = 0.96) between speech-language pathology raters. The MASA-C is a reliable and valid scale that is sensitive to differences in swallowing performance in HNC patients with and without dysphagia. Future longitudinal evaluation of this tool in larger samples is suggested. The development and refinement of this swallowing assessment tool for use in multidisciplinary HNC teams will facilitate earlier identification of patients with swallowing difficulties and enable more efficient allocation of resources to the management of dysphagia in this population. The MASA-C may also prove useful in future clinical HNC rehabilitation trials with this population.

SU-F-J-174: A Series of Computational Human Phantoms in DICOM-RT Format for Normal Tissue Dose Reconstruction in Epidemiological Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pyakuryal, A; Moroz, B; Lee, C

2016-06-15

Purpose: Epidemiological studies of second cancer risk in radiotherapy patients often require individualized dose estimates of normal tissues. Prior to 3D conformal radiation therapy planning, patient anatomy information was mostly limited to 2D radiological images or not even available. Generic patient CT images are often used in commercial radiotherapy treatment planning system (TPS) to reconstruct normal tissue doses. The objective of the current work was to develop a series of reference size computational human phantoms in DICOM-RT format for direct use in dose reconstruction in TPS. Methods: Contours of 93 organs and tissues were extracted from a series of pediatricmore » and adult hybrid computational human phantoms (newborn, 1-, 5-, 10-, 15-year-old, and adult males and females) using Rhinoceros software. A MATLAB script was created to convert the contours into the DICOM-RT structure format. The simulated CT images with the resolution of 1×1×3 mm3 were also generated from the binary phantom format and coupled with the DICOM-structure files. Accurate volumes of the organs were drawn in the format using precise delineation of the contours in converted format. Due to complex geometry of organs, higher resolution (1×1×1 mm3) was found to be more efficient in the conversion of newborn and 1-year-old phantoms. Results: Contour sets were efficiently converted into DICOM-RT structures in relatively short time (about 30 minutes for each phantom). A good agreement was observed in the volumes between the original phantoms and the converted contours for large organs (NRMSD<1.0%) and small organs (NRMSD<7.7%). Conclusion: A comprehensive series of computational human phantoms in DICOM-RT format was created to support epidemiological studies of second cancer risks in radiotherapy patients. We confirmed the DICOM-RT phantoms were successfully imported into the TPS programs of major vendors.« less

TU-F-BRB-02: Motion Artifacts and Suppression in MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, X.

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has highmore » temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant.« less

TU-F-BRB-03: Clinical Implementation of MR-Based Motion Management

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glide-Hurst, C.

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has highmore » temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant.« less

TU-PIS-Exhibit Hall-4: How to implement a dose monitoring solution in the real world: a technical perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Massey, S.

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has highmore » temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant.« less

TU-PIS-Exhibit Hall-1: Tools for Collecting and Analyzing Patient Dose Index Information from Imaging Equipment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, J.; Stanford University: Introduction

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has highmore » temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant.« less

TU-PIS-Exhibit Hall-5: Use of the Enterprise-wide Dose Tracking Software Radimetrics In an Academic Medical System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goode, A.

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has highmore » temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant.« less

TU-F-BRB-00: MRI-Based Motion Management for RT

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has highmore » temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant.« less

NOTE: A feasibility study of markerless fluoroscopic gating for lung cancer radiotherapy using 4DCT templates

NASA Astrophysics Data System (ADS)

Li, Ruijiang; Lewis, John H.; Cerviño, Laura I.; Jiang, Steve B.

2009-10-01

A major difficulty in conformal lung cancer radiotherapy is respiratory organ motion, which may cause clinically significant targeting errors. Respiratory-gated radiotherapy allows for more precise delivery of prescribed radiation dose to the tumor, while minimizing normal tissue complications. Gating based on external surrogates is limited by its lack of accuracy, while gating based on implanted fiducial markers is limited primarily by the risk of pneumothorax due to marker implantation. Techniques for fluoroscopic gating without implanted fiducial markers (markerless gating) have been developed. These techniques usually require a training fluoroscopic image dataset with marked tumor positions in the images, which limits their clinical implementation. To remove this requirement, this study presents a markerless fluoroscopic gating algorithm based on 4DCT templates. To generate gating signals, we explored the application of three similarity measures or scores between fluoroscopic images and the reference 4DCT template: un-normalized cross-correlation (CC), normalized cross-correlation (NCC) and normalized mutual information (NMI), as well as average intensity (AI) of the region of interest (ROI) in the fluoroscopic images. Performance was evaluated using fluoroscopic and 4DCT data from three lung cancer patients. On average, gating based on CC achieves the highest treatment accuracy given the same efficiency, with a high target coverage (average between 91.9% and 98.6%) for a wide range of nominal duty cycles (20-50%). AI works well for two patients out of three, but failed for the third patient due to interference from the heart. Gating based on NCC and NMI usually failed below 50% nominal duty cycle. Based on this preliminary study with three patients, we found that the proposed CC-based gating algorithm can generate accurate and robust gating signals when using 4DCT reference template. However, this observation is based on results obtained from a very limited dataset, and further investigation on a larger patient population has to be done before its clinical implementation.

TU-D-202-03: Gating Is the Best ITV Killer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Low, D.

Respiratory motion has long been recognized as an important factor affecting the precision of radiotherapy. After the introduction of the 4D CT to visualize the respiratory motion in 3D, the internal target volume (ITV) has been widely adopted as simple method to take the motion into account in treatment planning and delivery. The ITV is generated as the union of the CTVs as the patient goes through the respiratory cycle. Many issues have been identified with the ITV. In this session three alternatives for the ITV will be discussed: 1) An alternative motion-inclusive approach with better imaging and smaller margins,more » called mid-position CT. 2) The tracking approach and 3) The gating approach. The following topics will be addressed by Marcel van Herk (“Is ITV the correct motion encompassing strategy”): Magnitude of respiratory motion, effect of motion on radiotherapy, motion encompassing strategies, and software solutions to assist in motion encompassing strategies. Then Paul Keall (“Make margins simple: Use real-time target tracking”) will discuss tracking with: clinical drivers for tracking, current clinical status of tumor tracking, future tumor tracking technology, and margin margin challenges with and without tracking. Finally Daniel Low will discuss gating (“Gating is the best ITV killer”): why ITV in the first place, requirements for planning, requirements at the machine, benefits and costs. The session will end with a discussion and live demo of motion simulation software to illustrate the issues and explain the relative benefit and appropriate uses for the three methods. Learning Objectives: Explain the 4D imaging and treatment planning process. Summarize the various approaches to deal with respiratory motion during radiotherapy Discuss the tradeoffs involved when choosing one of the three discussed approaches. Explain in which situation each method is the best choice Research is partly funded by Elekta Oncology Systems and the Dutch Cancer Foundation; M. van Herk, Part of the research was funded by Elekta Oncology Systems and the Dutch Cancer Foundation.« less

Clinical applications of image guided-intensity modulated radiation therapy (IG-IMRT) for conformal avoidance of normal tissue

NASA Astrophysics Data System (ADS)

Gutierrez, Alonso Navar

2007-12-01

Recent improvements in imaging technology and radiation delivery have led to the development of advanced treatment techniques in radiotherapy which have opened the door for novel therapeutic approaches to improve the efficacy of radiation cancer treatments. Among these advances is image-guided, intensity modulated radiation therapy (IG-IMRT), in which imaging is incorporated to aid in inter-/intra-fractional target localization and to ensure accurate delivery of precise and highly conformal dose distributions. In principle, clinical implementation of IG-IMRT should improve normal tissue sparing and permit effective biological dose escalation thus widening the radiation therapeutic window and lead to increases in survival through improved local control of primary neoplastic diseases. Details of the development of three clinical applications made possible solely with IG-IMRT radiation delivery techniques are presented: (1) Laparoscopically implanted tissue expander radiotherapy (LITE-RT) has been developed to enhance conformal avoidance of normal tissue during the treatment of intra-abdominopelvic cancers. LITE-RT functions by geometrically displacing surrounding normal tissue and isolating the target volume through the interfractional inflation of a custom-shaped tissue expander throughout the course of treatment. (2) The unique delivery geometry of helical tomotherapy, a novel form of IG-IMRT, enables the delivery of composite treatment plan m which whole brain radiotherapy (WBRT) with hippocampal avoidance, hypothesized to reduce the risk of memory function decline and improve the patient's quality of life, and simultaneously integrated boost to multiple brain metastases to improve intracranial tumor control is achieved. (3) Escalation of biological dose to targets through integrated, selective subvolume boosts have been shown to efficiently increase tumor dose without significantly increasing normal tissue dose. Helical tomotherapy was used to investigate the feasibility of delivering a simultaneously integrated subvolume boost to canine nasal tumors and was found to dramatically increase estimated 1-year tumor control probability (TCP) without increasing the dose to the eyes, so as to preserve vision, and to the brain, so as to prevent neuropathy.

Parotid gland mean dose as a xerostomia predictor in low-dose domains.

PubMed

Gabryś, Hubert Szymon; Buettner, Florian; Sterzing, Florian; Hauswald, Henrik; Bangert, Mark

2017-09-01

Xerostomia is a common side effect of radiotherapy resulting from excessive irradiation of salivary glands. Typically, xerostomia is modeled by the mean dose-response characteristic of parotid glands and prevented by mean dose constraints to either contralateral or both parotid glands. The aim of this study was to investigate whether normal tissue complication probability (NTCP) models based on the mean radiation dose to parotid glands are suitable for the prediction of xerostomia in a highly conformal low-dose regime of modern intensity-modulated radiotherapy (IMRT) techniques. We present a retrospective analysis of 153 head and neck cancer patients treated with radiotherapy. The Lyman Kutcher Burman (LKB) model was used to evaluate predictive power of the parotid gland mean dose with respect to xerostomia at 6 and 12 months after the treatment. The predictive performance of the model was evaluated by receiver operating characteristic (ROC) curves and precision-recall (PR) curves. Average mean doses to ipsilateral and contralateral parotid glands were 25.4 Gy and 18.7 Gy, respectively. QUANTEC constraints were met in 74% of patients. Mild to severe (G1+) xerostomia prevalence at both 6 and 12 months was 67%. Moderate to severe (G2+) xerostomia prevalence at 6 and 12 months was 20% and 15%, respectively. G1 + xerostomia was predicted reasonably well with area under the ROC curve ranging from 0.69 to 0.76. The LKB model failed to provide reliable G2 + xerostomia predictions at both time points. Reduction of the mean dose to parotid glands below QUANTEC guidelines resulted in low G2 + xerostomia rates. In this dose domain, the mean dose models predicted G1 + xerostomia fairly well, however, failed to recognize patients at risk of G2 + xerostomia. There is a need for the development of more flexible models able to capture complexity of dose response in this dose regime.

TU-PIS-Exhibit Hall-3: Simultaneous tracking of patient and real time staff dose to optimize interventional workflow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boon, S.

The current clinical standard of organ respiratory imaging, 4D-CT, is fundamentally limited by poor soft-tissue contrast and imaging dose. These limitations are potential barriers to beneficial “4D” radiotherapy methods which optimize the target and OAR dose-volume considering breathing motion but rely on a robust motion characterization. Conversely, MRI imparts no known radiation risk and has excellent soft-tissue contrast. MRI-based motion management is therefore highly desirable and holds great promise to improve radiotherapy of moving cancers, particularly in the abdomen. Over the past decade, MRI techniques have improved significantly, making MR-based motion management clinically feasible. For example, cine MRI has highmore » temporal resolution up to 10 f/s and has been used to track and/or characterize tumor motion, study correlation between external and internal motions. New MR technologies, such as 4D-MRI and MRI hybrid treatment machines (i.e. MR-linac or MR-Co60), have been recently developed. These technologies can lead to more accurate target volume determination and more precise radiation dose delivery via direct tumor gating or tracking. Despite all these promises, great challenges exist and the achievable clinical benefit of MRI-based tumor motion management has yet to be fully explored, much less realized. In this proposal, we will review novel MR-based motion management methods and technologies, the state-of-the-art concerning MRI development and clinical application and the barriers to more widespread adoption. Learning Objectives: Discuss the need of MR-based motion management for improving patient care in radiotherapy. Understand MR techniques for motion imaging and tumor motion characterization. Understand the current state of the art and future steps for clinical integration. Henry Ford Health System holds research agreements with Philips Healthcare. Research sponsored in part by a Henry Ford Health System Internal Mentored Grant.« less

Outcome analysis of salvage radiotherapy for occult cervical cancer found after simple hysterectomy.

PubMed

Koh, Hyeon Kang; Jeon, Wan; Kim, Hak Jae; Wu, Hong-Gyun; Kim, Kyubo; Chie, Eui Kyu; Ha, Sung W

2013-12-01

The objective was to analyze the outcomes of the patients, who received salvage radiotherapy for incidentally discovered cervical cancer following simple hysterectomy, and to identify the influence of intracavitary radiotherapy on treatment outcomes. Data from 117 patients with occult cervical cancer who underwent simple hysterectomy followed by salvage radiotherapy from September 1979 to November 2010 were collected. All the patients received external beam radiotherapy with (n = 45) or without (n = 72) intracavitary radiotherapy. Local control, disease-free survival, overall survival and treatment-related toxicity were investigated. The median follow-up time was 75 months. The 5- and 10-year local control/disease-free survival/overall survival rates were 93/87/87% and 90/84/83%, respectively. Among 98 patients who had no residual disease and negative resection margin on surgical specimens, 32 (33%) received intracavitary radiotherapy and 66 (67%) did not. There were no differences in patient and tumor characteristics between patients treated with and without intracavitary radiotherapy. The 5-year local control rate for the non-intracavitary radiotherapy group was 93 versus 94% for the intracavitary radiotherapy group (P = 0.564); the disease-free survival rate was 88 versus 94% (P = 0.894); the overall survival rate was 95 versus 85% (P = 0.106), respectively. Among all patients, there were 5% of Grade 3 or higher late toxicities. Patients with occult invasive cervical cancer discovered following simple hysterectomy could be treated safely and effectively with salvage radiotherapy. For patients with no residual disease and negative resection margin, intracavitary radiotherapy could be omitted.

Assessment of three-dimensional setup errors in image-guided pelvic radiotherapy for uterine and cervical cancer using kilovoltage cone-beam computed tomography and its effect on planning target volume margins.

PubMed

Patni, Nidhi; Burela, Nagarjuna; Pasricha, Rajesh; Goyal, Jaishree; Soni, Tej Prakash; Kumar, T Senthil; Natarajan, T

2017-01-01

To achieve the best possible therapeutic ratio using high-precision techniques (image-guided radiation therapy/volumetric modulated arc therapy [IGRT/VMAT]) of external beam radiation therapy in cases of carcinoma cervix using kilovoltage cone-beam computed tomography (kV-CBCT). One hundred and five patients of gynecological malignancies who were treated with IGRT (IGRT/VMAT) were included in the study. CBCT was done once a week for intensity-modulated radiation therapy and daily in IGRT/VMAT. These images were registered with the planning CT scan images and translational errors were applied and recorded. In all, 2078 CBCT images were studied. The margins of planning target volume were calculated from the variations in the setup. The setup variation was 5.8, 10.3, and 5.6 mm in anteroposterior, superoinferior, and mediolateral direction. This allowed adequate dose delivery to the clinical target volume and the sparing of organ at risks. Daily kV-CBCT is a satisfactory method of accurate patient positioning in treating gynecological cancers with high-precision techniques. This resulted in avoiding geographic miss.

Measurement of charge- and mass-changing cross sections for 4He+12C collisions in the energy range 80-220 MeV/u for applications in ion beam therapy

NASA Astrophysics Data System (ADS)

Horst, Felix; Schuy, Christoph; Weber, Uli; Brinkmann, Kai-Thomas; Zink, Klemens

2017-08-01

4He ions are considered to be used for hadron radiotherapy due to their favorable physical and radiobiological properties. For an accurate dose calculation the fragmentation of the primary 4He ions occurring as a result of nuclear collisions must be taken into account. Therefore precise nuclear reaction models need to be implemented in the radiation transport codes used for dose calculation. A fragmentation experiment using thin graphite targets was conducted at the Heidelberg Ion Beam Therapy Center (HIT) to obtain new and precise 4He-nucleus cross section data in the clinically relevant energy range. Measured values for the charge-changing cross section, mass-changing cross section, as well as the inclusive 3He production cross section for 4He+12C collisions at energies between 80 and 220 MeV /u are presented. These data are compared to the 4He-nucleus reaction model by DeVries and Peng as well as to the parametrizations by Tripathi et al. and by Cucinotta et al., which are implemented in the treatment planning code trip98 and several other radiation transport codes.

Do sampling methods differ in their utility for ecological monitoring? Comparison of line-point intercept, grid-point intercept, and ocular estimate methods

USDA-ARS?s Scientific Manuscript database

This study compared the utility of three sampling methods for ecological monitoring based on: interchangeability of data (rank correlations), precision (coefficient of variation), cost (minutes/transect), and potential of each method to generate multiple indicators. Species richness and foliar cover...

Demand for radiotherapy in Spain.

PubMed

Rodríguez, A; Borrás, J M; López-Torrecilla, J; Algara, M; Palacios-Eito, A; Gómez-Caamaño, A; Olay, L; Lara, P C

2017-02-01

Assessing the demand for radiotherapy in Spain based on existing evidence to estimate the human resources and equipment needed so that every person in Spain has access to high-quality radiotherapy when they need it. We used data from the European Cancer Observatory on the estimated incidence of cancer in Spain in 2012, along with the evidence-based indications for radiotherapy developed by the Australian CCORE project, to obtain an optimal radiotherapy utilisation proportion (OUP) for each tumour. About 50.5 % of new cancers in Spain require radiotherapy at least once over the course of the disease. Additional demand for these services comes from reradiation therapy and non-melanoma skin cancer. Approximately, 25-30 % of cancer patients with an indication for radiotherapy do not receive it due to factors that include access, patient preference, familiarity with the treatment among physicians, and especially resource shortages, all of which contribute to its underutilisation. Radiotherapy is underused in Spain. The increasing incidence of cancer expected over the next decade and the greater frequency of reradiations necessitate the incorporation of radiotherapy demand into need-based calculations for cancer services planning.

Combinations of Radiotherapy and Immunotherapy for Melanoma: A Review of Clinical Outcomes

PubMed Central

Barker, Christopher A.; Postow, Michael A.

2015-01-01

Radiotherapy has long played a role in the management of melanoma. Recent advances have also demonstrated the efficacy of immunotherapy in the treatment of melanoma. Preclinical data suggest a biologic interaction between radiotherapy and immunotherapy. Several clinical studies corroborate these findings. This review will summarize the outcomes of studies reporting on patients with melanoma treated with a combination of radiotherapy and immunotherapy. Vaccine therapies often use irradiated melanoma cells, and may be enhanced by radiotherapy. The cytokines interferon-alpha and interleukin-2 have been combined with radiotherapy in several small studies, with some evidence suggesting increased toxicity and/or efficacy. Ipilimumab, a monoclonal antibody which blocks cytotoxic T-lymphocyte antigen-4, has been combined with radiotherapy in several notable case studies and series. Finally, pilot studies of adoptive cell transfer have suggested radiotherapy may improve the efficacy of treatment. The review will demonstrate that the combination of radiotherapy and immunotherapy has been reported in several notable case studies, series and clinical trials. These clinical results suggest interaction and the need for further study. PMID:24661650

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, V; Nguyen, D; Tran, A

Purpose: To develop and clinically implement 4π radiotherapy, an inverse optimization platform that maximally utilizes non-coplanar intensity modulated radiotherapy (IMRT) beams to significantly improve critical organ sparing. Methods: A 3D scanner was used to digitize the human and phantom subject surfaces, which were positioned in the computer assisted design (CAD) model of a TrueBeam machine to create a virtual geometrical model, based on which, the feasible beam space was calculated for different tumor locations. Beamlets were computed for all feasible beams using convolution/superposition. A column generation algorithm was employed to optimize patient specific beam orientations and fluence maps. Optimal routingmore » through all selected beams were calculated by a level set method. The resultant plans were converted to XML files and delivered to phantoms in the TrueBeam developer mode. Finally, 4π plans were recomputed in Eclipse and manually delivered to recurrent GBM patients. Results: Compared to IMRT utilizing manually selected beams and volumetric modulated arc therapy plans, markedly improved dosimetry was observed using 4π for the brain, head and neck, liver, lung, and prostate patients. The improvements were due to significantly improved conformality and reduced high dose spillage to organs mediolateral to the PTV. The virtual geometrical model was experimentally validated. Safety margins with 99.9% confidence in collision avoidance were included to the model based model accuracy estimates determined via 300 physical machine to phantom distance measurements. Automated delivery in the developer mode was completed in 10 minutes and collision free. Manual 4 π treatment on the GBM cases resulted in significant brainstem sparing and took 35–45 minutes including multiple images, which showed submillimeter cranial intrafractional motion. Conclusion: The mathematical modeling utilized in 4π is accurate to create and guide highly complex non-coplanar IMRT treatments that consistently and significantly outperform human-operator-created plans. Deliverability of such plans is clinically demonstrated. This work is funded by Varian Medical Systems and the NSF Graduate Research Fellowship DGE-1144087.« less

Spike timing precision of neuronal circuits.

PubMed

Kilinc, Deniz; Demir, Alper

2018-06-01

Spike timing is believed to be a key factor in sensory information encoding and computations performed by the neurons and neuronal circuits. However, the considerable noise and variability, arising from the inherently stochastic mechanisms that exist in the neurons and the synapses, degrade spike timing precision. Computational modeling can help decipher the mechanisms utilized by the neuronal circuits in order to regulate timing precision. In this paper, we utilize semi-analytical techniques, which were adapted from previously developed methods for electronic circuits, for the stochastic characterization of neuronal circuits. These techniques, which are orders of magnitude faster than traditional Monte Carlo type simulations, can be used to directly compute the spike timing jitter variance, power spectral densities, correlation functions, and other stochastic characterizations of neuronal circuit operation. We consider three distinct neuronal circuit motifs: Feedback inhibition, synaptic integration, and synaptic coupling. First, we show that both the spike timing precision and the energy efficiency of a spiking neuron are improved with feedback inhibition. We unveil the underlying mechanism through which this is achieved. Then, we demonstrate that a neuron can improve on the timing precision of its synaptic inputs, coming from multiple sources, via synaptic integration: The phase of the output spikes of the integrator neuron has the same variance as that of the sample average of the phases of its inputs. Finally, we reveal that weak synaptic coupling among neurons, in a fully connected network, enables them to behave like a single neuron with a larger membrane area, resulting in an improvement in the timing precision through cooperation.

Melatonin prevents possible radiotherapy-induced thyroid injury.

PubMed

Arıcıgil, Mitat; Dündar, Mehmet Akif; Yücel, Abitter; Eryılmaz, Mehmet Akif; Aktan, Meryem; Alan, Mehmet Akif; Fındık, Sıdıka; Kılınç, İbrahim

2017-12-01

We aimed to investigate the protective effect of melatonin in radiotherapy-induced thyroid gland injury in an experimental rat model. Thirty-two rats were divided into four groups: the control group, melatonin treatment group, radiotherapy group and melatonin plus radiotherapy group. The neck region of each rat was defined by simulation and radiated with 2 Gray (Gy) per min with 6-MV photon beams, for a total dose of 18 Gy. Melatonin was administered at a dose of 50 mg/kg through intraperitoneal injection, 15 min prior to radiation exposure. Thirty days after the beginning of the study, rats were decapitated and analyses of blood and thyroid tissue were performed. Tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β), thiobarbituric acid reactive substances (TBARS) and nitric oxide (NO) levels in the radiotherapy group were significantly higher than those in the melatonin plus radiotherapy group (p < .05), whereas interleukin-10 (IL-10) and glutathione (GSH) values were higher in the melatonin plus radiotherapy group (p < .05). The infiltration of inflammatory cells and percentage of apoptosis in the radiotherapy group were significantly higher than those in the melatonin plus radiotherapy group (p < .05). Melatonin helped protect thyroid gland structure against the undesired cytotoxic effects of radiotherapy in rats.

Radiation therapy for people with cancer: what do written information materials tell them?

PubMed

Smith, S K; Yan, B; Milross, C; Dhillon, H M

2016-07-01

This study aimed to compare and contrast the contents of different types of written patient information about radiotherapy, namely (1) hospital radiotherapy departments vs. cancer control organisations and (2) generic vs. tumour-specific materials. A coding framework, informed by existing patients' information needs literature, was developed and applied to 54 radiotherapy information resources. The framework comprised 12 broad themes; cancer diagnosis, general information about radiotherapy, treatment planning, daily treatment, side effects, self-care management, external radiotherapy, internal radiotherapy, impact on daily activities, post-treatment, psychosocial health and other content, such as a glossary. Materials produced by cancer organisations contained significantly more information than hospital resources on diagnosis, general radiotherapy information, internal radiotherapy and psychosocial health. However, hospital materials provided more information about treatment planning, daily treatment and the impact on daily activities. Compared to generic materials, tumour-specific resources were superior in providing information about diagnosis, daily treatment, side effects, post-treatment and psychosocial health. Information about internal radiotherapy, prognosis and chronic side effects were poorly covered by most resources. Collectively, hospital and cancer organisation resources complement each other in meeting patients' information needs. Identifying ways to consolidate different information sources could help comprehensively address patients' medical and psychosocial information needs about radiotherapy. © 2015 John Wiley & Sons Ltd.

Genome-wide transcription responses to synchrotron microbeam radiotherapy.

PubMed

Sprung, Carl N; Yang, Yuqing; Forrester, Helen B; Li, Jason; Zaitseva, Marina; Cann, Leonie; Restall, Tina; Anderson, Robin L; Crosbie, Jeffrey C; Rogers, Peter A W

2012-10-01

The majority of cancer patients achieve benefit from radiotherapy. A significant limitation of radiotherapy is its relatively low therapeutic index, defined as the maximum radiation dose that causes acceptable normal tissue damage to the minimum dose required to achieve tumor control. Recently, a new radiotherapy modality using synchrotron-generated X-ray microbeam radiotherapy has been demonstrated in animal models to ablate tumors with concurrent sparing of normal tissue. Very little work has been undertaken into the cellular and molecular mechanisms that differentiate microbeam radiotherapy from broad beam. The purpose of this study was to investigate and compare the whole genome transcriptional response of in vivo microbeam radiotherapy versus broad beam irradiated tumors. We hypothesized that gene expression changes after microbeam radiotherapy are different from those seen after broad beam. We found that in EMT6.5 tumors at 4-48 h postirradiation, microbeam radiotherapy differentially regulates a number of genes, including major histocompatibility complex (MHC) class II antigen gene family members, and other immunity-related genes including Ciita, Ifng, Cxcl1, Cxcl9, Indo and Ubd when compared to broad beam. Our findings demonstrate molecular differences in the tumor response to microbeam versus broad beam irradiation and these differences provide insight into the underlying mechanisms of microbeam radiotherapy and broad beam.

The intensity of radiotherapy-elicited immune response is associated with esophageal cancer clearance.

PubMed

Ma, Jin-lu; Jin, Long; Li, Yao-Dong; He, Chen-chen; Guo, Xi-jing; Liu, Rui; Yang, Yun-Yi; Han, Su-xia

2014-01-01

Radiation therapy is one of the standard therapeutic modalities for esophageal cancer, achieving its main antitumor efficacy through DNA damage. However, accumulating evidence shows that radiotherapy can substantially alter the tumor microenvironment, particularly with respect to its effects on immune cells. We hypothesized that the immune response elicited by radiotherapy may be as important as the radiation itself for successful treatment. More specifically, immunomodulatory cytokines may enhance the effectiveness of radiotherapy. To investigate this hypothesis, we measured changes in the serum interferon-gamma (IFN- γ ) and interleukin-2 (IL-2) concentrations during radiotherapy and compared these modifications with outcomes. We found that serum concentrations of IL-2 and IFN- γ were positively associated with local response to radiotherapy in esophageal cancer. More generally, the intensity of the radiotherapy-elicited immune response was positively associated with local response to radiotherapy in esophageal cancer. Changes in serum IL-2 and IFN- γ concentrations were further associated with increased risks of acute hematologic toxicity and acute organ toxicity of the esophagus, lung, and skin. These results suggest that deciphering the mechanisms of radiotherapy-elicited immune response may help in the development of therapeutic interventions that would enhance the efficacy of radiotherapy and convert some ineffective responses to effective responses.

Increased skin and mucosal toxicity in the combination of vemurafenib with radiation therapy.

PubMed

Merten, Ricarda; Hecht, Markus; Haderlein, Marlen; Distel, Luitpold; Fietkau, Rainer; Heinzerling, Lucie; Semrau, Sabine

2014-11-01

Palliative radiotherapy is often required for patients with metastatic malignant melanoma in the case of bone or brain metastases. Since BRAF inhibitor therapy is highly efficient in V600-mutated melanomas, there is hesitation to stop it during radiotherapy. Consequently, radiotherapy under simultaneous vemurafenib treatment is frequently needed. We report the case of a patient receiving palliative radiotherapy of spinal bone metastases before and during vemurafenib therapy. The skin reactions were quantitatively scored using computer-assisted digital image evaluation. Radiotherapy without vemurafenib was tolerated very well, whereas radiotherapy under simultaneous vemurafenib treatment resulted in accentuated skin reactions. Furthermore, the patient developed dysphagia and had to be hospitalized for parenteral nutrition. In the quantitative analysis, there was a twofold increase in pigmentation and erythema of the irradiated skin area of the thoracic spine when vemurafenib was combined with radiotherapy compared with radiotherapy treatment alone. This is the first reported case of a patient showing no complications during radiotherapy without vemurafenib but remarkable skin and mucosal toxicity under concurrent vemurafenib therapy. Thus, a genetically conditioned individually elevated radiosensitivity can definitely be excluded. Compared with other reported cases, radiosensitization was not limited to the skin, but also affected the esophageal mucosa. Vemurafenib is a strong radiosensitizer. Patients receiving radiotherapy under simultaneous vemurafenib treatment should be monitored very closely.

Calculations of dose distributions using a neural network model

NASA Astrophysics Data System (ADS)

Mathieu, R.; Martin, E.; Gschwind, R.; Makovicka, L.; Contassot-Vivier, S.; Bahi, J.

2005-03-01

The main goal of external beam radiotherapy is the treatment of tumours, while sparing, as much as possible, surrounding healthy tissues. In order to master and optimize the dose distribution within the patient, dosimetric planning has to be carried out. Thus, for determining the most accurate dose distribution during treatment planning, a compromise must be found between the precision and the speed of calculation. Current techniques, using analytic methods, models and databases, are rapid but lack precision. Enhanced precision can be achieved by using calculation codes based, for example, on Monte Carlo methods. However, in spite of all efforts to optimize speed (methods and computer improvements), Monte Carlo based methods remain painfully slow. A newer way to handle all of these problems is to use a new approach in dosimetric calculation by employing neural networks. Neural networks (Wu and Zhu 2000 Phys. Med. Biol. 45 913-22) provide the advantages of those various approaches while avoiding their main inconveniences, i.e., time-consumption calculations. This permits us to obtain quick and accurate results during clinical treatment planning. Currently, results obtained for a single depth-dose calculation using a Monte Carlo based code (such as BEAM (Rogers et al 2003 NRCC Report PIRS-0509(A) rev G)) require hours of computing. By contrast, the practical use of neural networks (Mathieu et al 2003 Proceedings Journées Scientifiques Francophones, SFRP) provides almost instant results and quite low errors (less than 2%) for a two-dimensional dosimetric map.

Calculations of dose distributions using a neural network model.

PubMed

Mathieu, R; Martin, E; Gschwind, R; Makovicka, L; Contassot-Vivier, S; Bahi, J

2005-03-07

The main goal of external beam radiotherapy is the treatment of tumours, while sparing, as much as possible, surrounding healthy tissues. In order to master and optimize the dose distribution within the patient, dosimetric planning has to be carried out. Thus, for determining the most accurate dose distribution during treatment planning, a compromise must be found between the precision and the speed of calculation. Current techniques, using analytic methods, models and databases, are rapid but lack precision. Enhanced precision can be achieved by using calculation codes based, for example, on Monte Carlo methods. However, in spite of all efforts to optimize speed (methods and computer improvements), Monte Carlo based methods remain painfully slow. A newer way to handle all of these problems is to use a new approach in dosimetric calculation by employing neural networks. Neural networks (Wu and Zhu 2000 Phys. Med. Biol. 45 913-22) provide the advantages of those various approaches while avoiding their main inconveniences, i.e., time-consumption calculations. This permits us to obtain quick and accurate results during clinical treatment planning. Currently, results obtained for a single depth-dose calculation using a Monte Carlo based code (such as BEAM (Rogers et al 2003 NRCC Report PIRS-0509(A) rev G)) require hours of computing. By contrast, the practical use of neural networks (Mathieu et al 2003 Proceedings Journees Scientifiques Francophones, SFRP) provides almost instant results and quite low errors (less than 2%) for a two-dimensional dosimetric map.

TU-C-12A-09: Modeling Pathologic Response of Locally Advanced Esophageal Cancer to Chemo-Radiotherapy Using Quantitative PET/CT Features, Clinical Parameters and Demographics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, H; Chen, W; Kligerman, S

2014-06-15

Purpose: To develop predictive models using quantitative PET/CT features for the evaluation of tumor response to neoadjuvant chemo-radiotherapy (CRT) in patients with locally advanced esophageal cancer. Methods: This study included 20 patients who underwent tri-modality therapy (CRT + surgery) and had {sup 18}F-FDG PET/CT scans before initiation of CRT and 4-6 weeks after completion of CRT but prior to surgery. Four groups of tumor features were examined: (1) conventional PET/CT response measures (SUVmax, tumor diameter, etc.); (2) clinical parameters (TNM stage, histology, etc.) and demographics; (3) spatial-temporal PET features, which characterize tumor SUV intensity distribution, spatial patterns, geometry, and associatedmore » changes resulting from CRT; and (4) all features combined. An optimal feature set was identified with recursive feature selection and cross-validations. Support vector machine (SVM) and logistic regression (LR) models were constructed for prediction of pathologic tumor response to CRT, using cross-validations to avoid model over-fitting. Prediction accuracy was assessed via area under the receiver operating characteristic curve (AUC), and precision was evaluated via confidence intervals (CIs) of AUC. Results: When applied to the 4 groups of tumor features, the LR model achieved AUCs (95% CI) of 0.57 (0.10), 0.73 (0.07), 0.90 (0.06), and 0.90 (0.06). The SVM model achieved AUCs (95% CI) of 0.56 (0.07), 0.60 (0.06), 0.94 (0.02), and 1.00 (no misclassifications). Using spatial-temporal PET features combined with conventional PET/CT measures and clinical parameters, the SVM model achieved very high accuracy (AUC 1.00) and precision (no misclassifications), significantly better than using conventional PET/CT measures or clinical parameters and demographics alone. For groups with a large number of tumor features (groups 3 and 4), the SVM model achieved significantly higher accuracy than the LR model. Conclusion: The SVM model using all features including quantitative PET/CT features accurately and precisely predicted pathologic tumor response to CRT in esophageal cancer. This work was supported in part by National Cancer Institute Grant R21 CA131979 and R01 CA172638. Shan Tan was supported in part by the National Natural Science Foundation of China 60971112 and 61375018, and by Fundamental Research Funds for the Central Universities 2012QN086.« less

Stereotactic radiation treatment planning and follow-up studies involving fused multimodality imaging.

PubMed

Hamm, Klaus D; Surber, Gunnar; Schmücking, Michael; Wurm, Reinhard E; Aschenbach, Rene; Kleinert, Gabriele; Niesen, A; Baum, Richard P

2004-11-01

Innovative new software solutions may enable image fusion to produce the desired data superposition for precise target definition and follow-up studies in radiosurgery/stereotactic radiotherapy in patients with intracranial lesions. The aim is to integrate the anatomical and functional information completely into the radiation treatment planning and to achieve an exact comparison for follow-up examinations. Special conditions and advantages of BrainLAB's fully automatic image fusion system are evaluated and described for this purpose. In 458 patients, the radiation treatment planning and some follow-up studies were performed using an automatic image fusion technique involving the use of different imaging modalities. Each fusion was visually checked and corrected as necessary. The computerized tomography (CT) scans for radiation treatment planning (slice thickness 1.25 mm), as well as stereotactic angiography for arteriovenous malformations, were acquired using head fixation with stereotactic arc or, in the case of stereotactic radiotherapy, with a relocatable stereotactic mask. Different magnetic resonance (MR) imaging sequences (T1, T2, and fluid-attenuated inversion-recovery images) and positron emission tomography (PET) scans were obtained without head fixation. Fusion results and the effects on radiation treatment planning and follow-up studies were analyzed. The precision level of the results of the automatic fusion depended primarily on the image quality, especially the slice thickness and the field homogeneity when using MR images, as well as on patient movement during data acquisition. Fully automated image fusion of different MR, CT, and PET studies was performed for each patient. Only in a few cases was it necessary to correct the fusion manually after visual evaluation. These corrections were minor and did not materially affect treatment planning. High-quality fusion of thin slices of a region of interest with a complete head data set could be performed easily. The target volume for radiation treatment planning could be accurately delineated using multimodal information provided by CT, MR, angiography, and PET studies. The fusion of follow-up image data sets yielded results that could be successfully compared and quantitatively evaluated. Depending on the quality of the originally acquired image, automated image fusion can be a very valuable tool, allowing for fast (approximately 1-2 minute) and precise fusion of all relevant data sets. Fused multimodality imaging improves the target volume definition for radiation treatment planning. High-quality follow-up image data sets should be acquired for image fusion to provide exactly comparable slices and volumetric results that will contribute to quality contol.

Who Should Bear the Cost of Convenience? A Cost-effectiveness Analysis Comparing External Beam and Brachytherapy Radiotherapy Techniques for Early Stage Breast Cancer.

PubMed

McGuffin, M; Merino, T; Keller, B; Pignol, J-P

2017-03-01

Standard treatment for early breast cancer includes whole breast irradiation (WBI) after breast-conserving surgery. Recently, accelerated partial breast irradiation (APBI) has been proposed for well-selected patients. A cost and cost-effectiveness analysis was carried out comparing WBI with two APBI techniques. An activity-based costing method was used to determine the treatment cost from a societal perspective of WBI, high dose rate brachytherapy (HDR) and permanent breast seed implants (PBSI). A Markov model comparing the three techniques was developed with downstream costs, utilities and probabilities adapted from the literature. Sensitivity analyses were carried out for a wide range of variables, including treatment costs, patient costs, utilities and probability of developing recurrences. Overall, HDR was the most expensive ($14 400), followed by PBSI ($8700), with WBI proving the least expensive ($6200). The least costly method to the health care system was WBI, whereas PBSI and HDR were less costly for the patient. Under cost-effectiveness analyses, downstream costs added about $10 000 to the total societal cost of the treatment. As the outcomes are very similar between techniques, WBI dominated under cost-effectiveness analyses. WBI was found to be the most cost-effective radiotherapy technique for early breast cancer. However, both APBI techniques were less costly to the patient. Although innovation may increase costs for the health care system it can provide cost savings for the patient in addition to convenience. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Poster - Thur Eve - 11: A realistic respiratory trace generator and its application to respiratory management techniques.

PubMed

Quirk, S; Becker, N; Smith, W L

2012-07-01

Respiratory motion complicates radiotherapy treatment of thoracic and abdominal tumours. Simplified respiratory motions such as sinusoidal and single patient traces are often used to determine the impact of motion on respiratory management techniques in radiotherapy. Such simplifications only accurately model a small portion of patients, as most patients exhibit variability and irregularity beyond these models. We have preformed a comprehensive analysis of respiratory motion and developed a software tool that allows for explicit inclusion of variability. We utilize our realistic respiratory generator to customize respiratory traces to test the robustness of the estimate of internal gross target volumes (IGTV) by 4DCT and CBCT. We confirmed that good agreement is found between 4DCT and CBCT for regular breathing motion. When amplitude variability was introduced the accuracy of the estimate slightly, but the absolute differences were still < 3 mm for both modalities. Poor agreement was shown with the addition of baseline drifts. Both modalities were found to underestimate the IGTV by as much as 30% for 4DCT and 25% for CBCT. Both large and small drifts deteriorated the estimate accuracy. The respiratory trace generator was advantageous for examining the difference between 4DCT and CBCT IGTV estimation under variable motions. It provided useful implementation abilities to test specific attributes of respiratory motion and detected issues that were not seen with the regular motion studies. This is just one example of how the respiratory trace generator can be utilized to test applications of respiratory management techniques. © 2012 American Association of Physicists in Medicine.

The impact of RTOG 0614 and RTOG 0933 trials in routine clinical practice: The US Survey of Utilization of Memantine and IMRT planning for hippocampus sparing in patients receiving whole brain radiotherapy for brain metastases.

PubMed

Slade, Alexander N; Stanic, Sinisa

2016-03-01

Two recent clinical trials, phase III RTOG 0614 and phase II RTOG 0933, showed some effectiveness of Memantine and IMRT planning for hippocampus sparing, among patients receiving whole brain radiotherapy (WBRT) for brain metastases; however, their use in routine clinical practice is unknown. A survey was sent to 1933 radiation oncologists in the US. Data collected included utilization of Memantine and hippocampus sparing, reasons for adoption and non-adoption, and demographic variables. A total of 196 radiation oncologists responded to the survey, with 64% reporting using Memantine in almost none of the patients receiving WBRT for brain metastases, and only 11% considering Memantine for <10% of their patients. The most common reason for not using Memantine was a poor patient performance status, and limited life expectancy. Likewise, 56% of radiation oncologists would not change their clinical practice to include hippocampus sparing IMRT in patients receiving WBRT based on the results of RTOG 0933. Further validation of hippocampus sparing in a phase III trial was supported by 71% of radiation oncologists, whereas further exploration of Memantine for this purpose in a phase III trial was supported by 42%. At this time, the majority of surveyed radiation oncologists in the US do not use Memantine, or IMRT planning for hippocampus sparing in patients receiving WBRT. Further validation of the hippocampus sparing concept in a phase III trial was supported, before adopting it in routine clinical practice. Copyright © 2015 Elsevier Inc. All rights reserved.

Solid Lubricants for Space Structures

DTIC Science & Technology

1993-04-17

will utilize mechanically interlocked hardware (caged bearings or bearings for ultra precision gimbals pointing mechanisms) controlled through precision...structure unless the lubricant were of low vapor pressure and/or suitably sealed to I prevent molecular effusion . While temperatures within spacecraft or...incorporation in the continuous cast system. The die made of graphite, consists of a plurality of openings or holes located in the die and positioned (unlined

SU-E-P-56: Dosimetric Comparison of Three Post Modified Radical Mastectomy Radiotherapy Techniques for Locally Advanced Left-Sided Breast Cancer and Beyond

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, C; Zhang, W; Lu, J

2015-06-15

Purpose: To compare the dosimetry of post modified radical mastectomy radiotherapy (PMRMRT) for left-sided breast cancer using 3-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). Methods: We created ten sets of PMRMRT plans for ten consecutive patients and utilized two tangential and one or two supraclavicular beams in 3DCRT, a total of 5 beams in IMRT and two optimized partial arcs in VMAT. The difference in results between any two of the three new plans, between new and previous 3DCRT plans were compared and analyzed by ANOVA (α =0.05) and paired-sample t-test respectively. Pmore » values less than 0.05 were considered statistically significant. Results: Both IMRT and VMAT plans had similar PTV coverage, hotspot area and conformity (all p>0.05), and significantly higher PTV coverage compared with new 3DCRT (both p<0.001). IMRT plans had significantly less heart and left lung radiation exposure compared with VMAT (all p<0.05). The 3DCRT plans with larger estimated CTV displacement had better target coverage but worse OARs sparing compared to those with smaller one. Conclusion: IMRT has dosimetrical advantages over the other two techniques in PMRMRT for left-sided breast cancer. Individually quantifying and minimizing CTV displacement can significantly improve dosage distribution. This work was supported by the Medical Scientific Research Foundation of Guangdong Procvince (A2014455 to Changchun Ma)« less

Pilot study of postoperative adjuvant chemoradiation for advanced gastric cancer: Adjuvant 5-FU/cisplatin and chemoradiation with capecitabine

PubMed Central

Lee, Hyung-Sik; Choi, Youngmin; Hur, Won-Joo; Kim, Hyo-Jin; Kwon, Hyuk-Chan; Kim, Sung-Hyun; Kim, Jae-Seok; Lee, Jong-Hoon; Jung, Ghap-Joong; Kim, Min-Chan

2006-01-01

AIM: To evaluate the efficacy and toxicity of postoperative chemoradiation using FP chemotherapy and oral capecitabine during radiation for advanced gastric cancer following curative resection. METHODS: Thirty-one patients who had underwent a potentially curative resection for Stage III and IV (M0) gastric cancer were enrolled. Therapy consists of one cycle of FP (continuous infusion of 5-FU 1000 mg/m2 on d 1 to 5 and cisplatin 60 mg/m2 on d 1) followed by 4500 cGy (180 cGy/d) with capecitabine (1650 mg/m2 daily throughout radiotherapy). Four wk after completion of the radiotherapy, patients received three additional cycles of FP every three wk. The median follow-up duration was 22.2 mo. RESULTS: The 3-year disease free and overall survival in this study were 82.7% and 83.4%, respectively. Four patients (12.9%) showed relapse during follow-up. Eight patients did not complete all planned adjuvant therapy. Grade 3/4 toxicities included neutropenia in 50.2%, anemia in 12.9%, thrombocytopenia in 3.2% and nausea/vomiting in 3.2%. Neither grade 3/4 hand foot syndrome nor treatment related febrile neutropenia or death were observed. CONCLUSION: These preliminary results suggest that this postoperative adjuvant chemoradiation regimen of FP before and after capecitabine and concurrent radiotherapy appears well tolerated and offers a comparable toxicity profile to the chemoradiation regimen utilized in INT-0116. This treatment modality allowed successful loco-regional control rate and 3-year overall survival. PMID:16489675

WE-EF-BRD-04: MR in the OR: The Growth and Applications of MRI for Interventional Radiology and Surgery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fahrig, R.

MRI-guided treatment is a growing area of medicine, particularly in radiotherapy and surgery. The exquisite soft tissue anatomic contrast offered by MRI, along with functional imaging, makes the use of MRI during therapeutic procedures very attractive. Challenging the utility of MRI in the therapy room are many issues including the physics of MRI and the impact on the environment and therapeutic instruments, the impact of the room and instruments on the MRI; safety, space, design and cost. In this session, the applications and challenges of MRI-guided treatment will be described. The session format is: Past, present and future: MRI-guided radiotherapymore » from 2005 to 2025: Jan Lagendijk Battling Maxwell’s equations: Physics challenges and solutions for hybrid MRI systems: Paul Keall I want it now!: Advances in MRI acquisition, reconstruction and the use of priors to enable fast anatomic and physiologic imaging to inform guidance and adaptation decisions: Yanle Hu MR in the OR: The growth and applications of MRI for interventional radiology and surgery: Rebecca Fahrig Learning Objectives: To understand the history and trajectory of MRI-guided radiotherapy To understand the challenges of integrating MR imaging systems with linear accelerators To understand the latest in fast MRI methods to enable the visualisation of anatomy and physiology on radiotherapy treatment timescales To understand the growing role and challenges of MRI for image-guided surgical procedures My disclosures are publicly available and updated at: http://sydney.edu.au/medicine/radiation-physics/about-us/disclosures.php.« less

WE-EF-BRD-02: Battling Maxwell’s Equations: Physics Challenges and Solutions for Hybrid MRI Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keall, P.

MRI-guided treatment is a growing area of medicine, particularly in radiotherapy and surgery. The exquisite soft tissue anatomic contrast offered by MRI, along with functional imaging, makes the use of MRI during therapeutic procedures very attractive. Challenging the utility of MRI in the therapy room are many issues including the physics of MRI and the impact on the environment and therapeutic instruments, the impact of the room and instruments on the MRI; safety, space, design and cost. In this session, the applications and challenges of MRI-guided treatment will be described. The session format is: Past, present and future: MRI-guided radiotherapymore » from 2005 to 2025: Jan Lagendijk Battling Maxwell’s equations: Physics challenges and solutions for hybrid MRI systems: Paul Keall I want it now!: Advances in MRI acquisition, reconstruction and the use of priors to enable fast anatomic and physiologic imaging to inform guidance and adaptation decisions: Yanle Hu MR in the OR: The growth and applications of MRI for interventional radiology and surgery: Rebecca Fahrig Learning Objectives: To understand the history and trajectory of MRI-guided radiotherapy To understand the challenges of integrating MR imaging systems with linear accelerators To understand the latest in fast MRI methods to enable the visualisation of anatomy and physiology on radiotherapy treatment timescales To understand the growing role and challenges of MRI for image-guided surgical procedures My disclosures are publicly available and updated at: http://sydney.edu.au/medicine/radiation-physics/about-us/disclosures.php.« less

Role of radiotherapy fractionation in head and neck cancers (MARCH): an updated meta-analysis

PubMed Central

Lacas, Benjamin; Bourhis, Jean; Overgaard, Jens; Zhang, Qiang; Gregoire, Vincent; Nankivell, Matthew; Zackrisson, Bjorn; Szutkowski, Zbigniew; Suwiński, Rafał; Poulsen, Michael; O’Sullivan, Brian; Corvo, Renzo; Laskar, Sarbani Ghosh; Fallai, Carlo; Yamazaki, Hideya; Dobrowsky, Werner; Cho, Kwan Ho; Garden, Adam S; Langendijk, Johannes A; Viegas, Celia Maria Pais; Hay, John; Lotayef, Mohamed; Parmar, Mahesh K B; Auperin, Anne; van Herpen, Carla; Maingon, Philippe; Trotti, Andy M; Grau, Cai; Pignon, Jean-Pierre; Blanchard, Pierre

2017-01-01

Summary Background The Meta-Analysis of Radiotherapy in squamous cell Carcinomas of Head and neck (MARCH) showed that altered fractionation radiotherapy is associated with improved overall and progression-free survival compared with conventional radiotherapy, with hyperfractionated radiotherapy showing the greatest benefit. This update aims to confirm and explain the superiority of hyperfractionated radiotherapy over other altered fractionation radiotherapy regimens and to assess the benefit of altered fractionation within the context of concomitant chemotherapy with the inclusion of new trials. Methods For this updated meta-analysis, we searched bibliography databases, trials registries, and meeting proceedings for published or unpublished randomised trials done between Jan 1, 2009, and July 15, 2015, comparing primary or postoperative conventional fractionation radiotherapy versus altered fractionation radiotherapy (comparison 1) or conventional fractionation radiotherapy plus concomitant chemotherapy versus altered fractionation radiotherapy alone (comparison 2). Eligible trials had to start randomisation on or after Jan 1, 1970, and completed accrual before Dec 31, 2010; had to have been randomised in a way that precluded prior knowledge of treatment assignment; and had to include patients with non-metastatic squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx undergoing first-line curative treatment. Trials including a non-conventional radiotherapy control group, investigating hypofractionated radiotherapy, or including mostly nasopharyngeal carcinomas were excluded. Trials were grouped in three types of altered fractionation: hyperfractionated, moderately accelerated, and very accelerated. Individual patient data were collected and combined with a fixed-effects model based on the intention-to-treat principle. The primary endpoint was overall survival. Findings Comparison 1 (conventional fractionation radiotherapy vs altered fractionation radiotherapy) included 33 trials and 11 423 patients. Altered fractionation radiotherapy was associated with a significant benefit on overall survival (hazard ratio [HR] 0·94, 95% CI 0·90–0·98; p=0·0033), with an absolute difference at 5 years of 3·1% (95% CI 1·3–4·9) and at 10 years of 1·2% (−0·8 to 3·2). We found a significant interaction (p=0·051) between type of fractionation and treatment effect, the overall survival benefit being restricted to the hyperfractionated group (HR 0·83, 0·74–0·92), with absolute differences at 5 years of 8·1% (3·4 to 12·8) and at 10 years of 3·9% (−0·6 to 8·4). Comparison 2 (conventional fractionation radiotherapy plus concomitant chemotherapy versus altered fractionation radiotherapy alone) included five trials and 986 patients. Overall survival was significantly worse with altered fractionation radiotherapy compared with concomitant chemoradiotherapy (HR 1·22, 1·05–1·42; p=0·0098), with absolute differences at 5 years of −5·8% (−11·9 to 0·3) and at 10 years of −5·1% (−13·0 to 2·8). Interpretation This update confirms, with more patients and a longer follow-up than the first version of MARCH, that hyperfractionated radiotherapy is, along with concomitant chemoradiotherapy, a standard of care for the treatment of locally advanced head and neck squamous cell cancers. The comparison between hyperfractionated radiotherapy and concomitant chemoradiotherapy remains to be specifically tested. PMID:28757375

Trend in and Correlates of Undergoing Radiotherapy in Taiwanese Cancer Patients' Last Month of Life.

PubMed

Hung, Yen-Ni; Cheng, Skye Hung-Chun; Liu, Tsang-Wu; Chang, Wen-Cheng; Chen, Jen-Shi; Tang, Siew Tzuh

2016-09-01

A significant proportion of cancer patients at end of life (EOL) undergo radiotherapy, but this evidence is not from nationwide population-based studies. The aims of this population-based study were to investigate the trend in undergoing radiotherapy among Taiwanese cancer patients' last month of life (EOL radiotherapy) in 2001-2010 and to identify factors associated with EOL radiotherapy. This was a population-based retrospective cohort study analyzing data from Taiwan's national death registry, cancer registry, and National Health Insurance claims for EOL radiotherapy using multilevel generalized linear mixed modeling. Participants were Taiwanese cancer patients (N = 339,546) who died in 2001-2010. Overall, 8.59% (7.97%-9.85%) of patients underwent EOL radiotherapy with a decreasing trend over time. Correlates of EOL radiotherapy included male gender, younger age, residing in less urbanized areas, diagnosis of lung cancer, metastatic disease, death within two years of diagnosis, and without comorbidities. Cancer patients were more likely to undergo EOL radiotherapy if they received primary care from medical oncologists and pediatricians, in a nonprofit, teaching hospital with a larger case volume of terminally ill cancer patients, and greater EOL care intensity. Approximately one-tenth of Taiwanese cancer patients underwent EOL radiotherapy with a decreasing trend over time. Undergoing EOL radiotherapy was associated with demographics, disease characteristics, physician specialty, and primary hospital's characteristics and EOL care practice patterns. Clinical and financial interventions should target hospitals/physicians that tend to aggressively treat at-risk cancer patients at EOL to carefully evaluate the appropriateness and effectiveness of using EOL radiotherapy. Copyright © 2016 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

The role of radiotherapy in the management of patients with diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline.

PubMed

Ryken, Timothy C; Parney, Ian; Buatti, John; Kalkanis, Steven N; Olson, Jeffrey J

2015-12-01

(1) What is the optimal role of external beam radiotherapy in the management of adult patients with newly diagnosed low-grade glioma (LGG) in terms of improving outcome (i.e., survival, complications, seizure control or other reported outcomes of interest)? (2) Which radiation strategies (dose, timing, fractionation, stereotactic radiation, brachytherapy, chemotherapy) improve outcomes compared to standard external beam radiation therapy in the initial management of low grade gliomas in adults? (3) Do specific factors (e.g., age, volume, extent of resection, genetic subtype) identify subgroups with better outcomes following radiation therapy than the general population of adults with newly diagnosed low-grade gliomas? These recommendations apply to adults with newly diagnosed diffuse LGG. OUTCOMES IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA TREATED WITH RADIOTHERAPY: Level I Radiotherapy is recommended in the management of newly diagnosed low-grade glioma in adults to prolong progression free survival, irrespective of extent of resection. Level II Radiotherapy is recommended in the management of newly diagnosed low grade glioma in adults as an equivalent alternative to observation in preserving cognitive function, irrespective of extent of resection. Level III Radiotherapy is recommended in the management of newly diagnosed low grade glioma in adults to improve seizure control in patients with epilepsy and subtotal resection. Level III Radiotherapy is recommended in the management of newly diagnosed low-grade glioma in adults to prolong overall survival in patients with subtotal resection. Level III Consideration of the risk of radiation induced morbidity, including cognitive decline, imaging abnormalities, metabolic dysfunction and malignant transformation, is recommended when the delivery of radiotherapy is selected in the management of newly diagnosed low-grade glioma in adults. STRATEGIES OF RADIOTHERAPY IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA: Level I Lower dose radiotherapy is recommended as an equivalent alternative to higher dose immediate postoperative radiotherapy (45-50.4 vs. 59.4-64.8 Gy) in the management of newly diagnosed low-grade glioma in adults with reduced toxicity. Level III Delaying radiotherapy until recurrence or progression is recommended as an equivalent alternative to immediate postoperative radiotherapy in the management of newly diagnosed low-grade glioma in adults but may result in shorter time to progression. Level III The addition of chemotherapy to radiotherapy is not recommended over whole brain radiotherapy alone in the management of low-grade glioma, as it provides no additional survival benefit. Level III Limited-field radiotherapy is recommended over whole brain radiotherapy in the management of low-grade glioma. Level III Either stereotactic radiosurgery or brachytherapy are recommended as acceptable alternatives to external radiotherapy in selected patients. PROGNOSTIC FACTORS IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA TREATED WITH RADIOTHERAPY: Level II It is recommended that age greater than 40 years, astrocytic pathology, diameter greater than 6 cm, tumor crossing the midline and preoperative neurological deficit be considered as negative prognostic indicators when predicting overall survival in adult low grade glioma patients treated with radiotherapy. Level II It is recommended that smaller tumor size, extent of surgical resection and higher mini-mental status exam be considered as positive prognostic indicators when predicting overall survival and progression free survival in patients in adult low grade glioma patients treated with radiotherapy. Level III It is recommended that seizures at presentation, presence of oligodendroglial histological component and 1p19q deletion (along with additional relevant factors-see Table 1) be considered as positive prognostic indicators when predicting response to radiotherapy in adults with low grade gliomas. Level III It is recommended that increasing age, decreasing performance status, decreasing cognition, presence of astrocytic histological component (along with additional relevant factors (see Tables 1, 2) be considered as negative prognostic indicators when predicting response to radiotherapy.

Radiotherapy of rectal cancer in elderly patients: Real-world data assessment in a decade.

PubMed

Diao, Peng; Langrand-Escure, Julien; Garcia, Max-Adrien; Espenel, Sophie; Rehailia-Blanchard, Amel; de Lavigerie, Blandine; Vial, Nicolas; de Laroche, Guy; Vallard, Alexis; Magné, Nicolas

2018-06-01

There is paucity of data on the efficacy and toxicity of radiotherapy in rectal cancer (RC) elderly patients. The objective was to identify management strategies and resulting outcomes in RC patients ≥70 years undergoing radiotherapy. A retrospective study included consecutive RC patients ≥70 years undergoing rectal radiotherapy. From 2004-2015, 340 RC patients underwent pre-operative (n = 238; 70%), post-operative (n = 41, 12%), or exclusive (n = 61, 18%) radiotherapy, with a median age of 78.5 years old (range: 70-96). Radiotherapy protocols were tailored, with 54 different radiotherapy programs (alteration of the total dose, and/or fractionation, and/or volume). Median follow-up was 27.1 months. Acute and late grade 3-4 radio-induced toxicities were reported in 3.5% and 0.9% of patients. Metastatic setting (OR = 6.60, CI95% 1.47-46.03, p = 0.02), exclusive radiotherapy (OR = 5.08, CI95% 1.48-18.21, p = 0.009), and intensity-modulated radiotherapy (OR = 6.42, CI95% 1.31-24.73, p = 0.01) were associated with grade ≥3 acute toxicities in univariate analysis. Exclusive radiotherapy (OR = 9.79, CI95% 2.49-43.18, p = 0.001) and intensity-modulated radiotherapy (OR = 12.62, CI95% 2.05-71.26, p = 0.003) were independent predictive factors of grade ≥3 acute toxicities in multivariate analysis. A complete pathological response was achieved in 12 out of 221 pre-operative patients (5.4%). Age, tumor stage, and surgery were independent predictive factors of survival in multivariate analysis. At end of follow-up, 7.1% of patients experienced local relapse. Radiotherapy for RC in elderly patients appeared safe and manageable, perhaps due to the tailoring of radiotherapy protocols. Tailored management resulted in acceptable rate of local tumor control. Copyright © 2018 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Oral mucosal melanoma treated with carbon ion radiotherapy: a case report.

PubMed

Musha, Atsushi; Saitoh, Jun-Ichi; Shirai, Katsuyuki; Yokoo, Satoshi; Ohno, Tatsuya; Nakano, Takashi

2016-10-18

Oral mucosal melanoma is a rare disease with a relatively poor prognosis. Carbon ion radiotherapy has been shown to be effective against radiotherapy-resistant tumors owing to its excellent dose concentration and high biological effect. Our patient was a 66-year-old Japanese man with oral mucosal melanoma of his right maxillary gingiva (T4aN0M0). He received carbon ion radiotherapy at 57.6 Gy (relative biological effectiveness) in 16 fractions for 4 weeks. Concomitant chemotherapy (dacarbazine + nimustine + vincristine) was administered at the same time as carbon ion radiotherapy initiation. Two courses of adjuvant chemotherapy were given after carbon ion radiotherapy. Although he experienced grade 2 acute oral mucositis, his symptoms improved within a few weeks of undergoing carbon ion radiotherapy. He was alive at the time of reporting, 35 months after treatment, without any recurrence. Late toxicity has not been observed. Carbon ion radiotherapy for oral mucosal melanoma resulted in a good local effect.

Lung Cancer: Posttreatment Imaging: Radiation Therapy and Imaging Findings.

PubMed

Benveniste, Marcelo F; Welsh, James; Viswanathan, Chitra; Shroff, Girish S; Betancourt Cuellar, Sonia L; Carter, Brett W; Marom, Edith M

2018-05-01

In this review, we discuss the different radiation delivery techniques available to treat non-small cell lung cancer, typical radiologic manifestations of conventional radiotherapy, and different patterns of lung injury and temporal evolution of the newer radiotherapy techniques. More sophisticated techniques include intensity-modulated radiotherapy, stereotactic body radiotherapy, proton therapy, and respiration-correlated computed tomography or 4-dimensional computed tomography for radiotherapy planning. Knowledge of the radiation treatment plan and technique, the completion date of radiotherapy, and the temporal evolution of radiation-induced lung injury is important to identify expected manifestations of radiation-induced lung injury and differentiate them from tumor recurrence or infection. Published by Elsevier Inc.

Recent Advances in Image-Guided Radiotherapy for Head and Neck Carcinoma

PubMed Central

Nath, Sameer K.; Simpson, Daniel R.; Rose, Brent S.; Sandhu, Ajay P.

2009-01-01

Radiotherapy has a well-established role in the management of head and neck cancers. Over the past decade, a variety of new imaging modalities have been incorporated into the radiotherapy planning and delivery process. These technologies are collectively referred to as image-guided radiotherapy and may lead to significant gains in tumor control and radiation side effect profiles. In the following review, these techniques as they are applied to head and neck cancer patients are described, and clinical studies analyzing their use in target delineation, patient positioning, and adaptive radiotherapy are highlighted. Finally, we conclude with a brief discussion of potential areas of further radiotherapy advancement. PMID:19644564

A multiple ion counter total evaporation (MICTE) method for precise analysis of plutonium by thermal ionization mass spectrometry

DOE PAGES

Inglis, Jeremy D.; Maassen, Joel; Kara, Azim; ...

2017-04-28

This study presents a total evaporation method for the analysis of sub-picogram quantities of Pu, utilizing an array of multiple ion counters. Data from three standards are presented to assess the utility of the technique. An external precision of 1.5% RSD (2σ) was achieved on aliquots approaching 100 fg for the minor 240Pu isotope. Accurate analysis of <1 femtogram of 240Pu, is achievable, with an external reproducibility of better than 10% RSD (2σ). Finally, this new technique represents a significant advance in the total evaporation method and will allow routine measurement of femtogram sized Pu samples by thermal ionization massmore » spectrometry.« less

Fundamental Characteristics of Bioprint on Calcium Alginate Gel

NASA Astrophysics Data System (ADS)

Umezu, Shinjiro; Hatta, Tatsuru; Ohmori, Hitoshi

2013-05-01

The goal of this study is to fabricate precision three-dimensional (3D) biodevices those are micro fluidics and artificial organs utilizing digital fabrication. Digital fabrication is fabrication method utilizing inkjet technologies. Electrostatic inkjet is one of the inkjet technologies. The electrostatic inkjet method has following two merits; those are high resolution to print and ability to eject highly viscous liquid. These characteristics are suitable to print biomaterials precisely. We are now applying for bioprint. In this paper, the electrostatic inkjet method is applied for fabrication of 3D biodevices that has cave like blood vessel. When aqueous solution of sodium alginate is printed to aqueous solution of calcium chloride, calcium alginate is produced. 3D biodevices are fabricated in case that calcium alginate is piled.

A multiple ion counter total evaporation (MICTE) method for precise analysis of plutonium by thermal ionization mass spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inglis, Jeremy D.; Maassen, Joel; Kara, Azim

This study presents a total evaporation method for the analysis of sub-picogram quantities of Pu, utilizing an array of multiple ion counters. Data from three standards are presented to assess the utility of the technique. An external precision of 1.5% RSD (2σ) was achieved on aliquots approaching 100 fg for the minor 240Pu isotope. Accurate analysis of <1 femtogram of 240Pu, is achievable, with an external reproducibility of better than 10% RSD (2σ). Finally, this new technique represents a significant advance in the total evaporation method and will allow routine measurement of femtogram sized Pu samples by thermal ionization massmore » spectrometry.« less

Radiotherapy changes salivary properties and impacts quality of life of children with Hodgkin disease.

PubMed

Marangoni-Lopes, L; Rodrigues, L P; Mendonça, R H; Nobre-Dos Santos, M

2016-12-01

We aimed to perform a longitudinal investigation of the effects of radiotherapy on salivary flow rate, pH, buffering capacity, and protein composition of saliva and on the quality of life of children with Hodgkin disease. Ten children (6-16-year-old) with Hodgkin disease and 10 matched healthy children were investigated. Stimulated and non-stimulated saliva samples were collected at baseline, after 1080 and 2160cGy of radiation, and 1, 2, and 3 months post-radiotherapy. The salivary flow rate was expressed as mL/min. Buffer capacity was determined by titration. Amylase activity, immunoglobulin A, mucin, and lactoferrin concentrations were determined by ELISA. Quality of life was assessed by Quality of Life - Head and Neck module 35 questionnaire. We found that radiotherapy caused hyposalivation at 1080cGy and 1 month after radiotherapy and reduced buffering capacity at 2160cGy. Mucin concentration and amylase activity in non-stimulated saliva increased 1 month after radiotherapy. Lactoferrin concentration increased during and after radiotherapy. Immunoglobulin A concentration increased at 1080cGy, 1 and 2 months, for non-stimulated saliva and at 2160cGy and 1 month for stimulated saliva. Children reported more pain after radiotherapy and more xerostomia during radiotherapy. We concluded that the radiotherapy protocol affected the children's salivary properties and children's quality of life. Copyright © 2016 Elsevier Ltd. All rights reserved.

The med AUSTRON/OGRO patterns of care study on radiotherapy indications in Austria.

PubMed

Mock, Ulrike; Mayer, Ramona; Potter, Richard; Jäger, Robert; Vutuc, Christian; Eiter, Helmut; Hammer, Josef; Hawliczek, Robert; Hirn, Brigitte; Knocke-Abulesz, Tomas-Henrik; Kogelnik, Hans-Dieter; Lukas, Peter; Nechville, Elisabeth; Pakisch, Brigitte; Papauschek, Michael; Ing Raunik, Wolfgang; Rhomberg, Walter; Sabitzer, Hubert; Schratter-Sehn, Annemarie; Sedlmayer, Felix; Wedrich, Irene; Auberger, Thomas

2004-12-01

In Austria a national survey was conducted by Med AUSTRON/Osterreichische Gesellschaft for Radio--Onkologie, Radiobiologie und Medizinische Radiophysik (OGRO) in order to estimate the indications, patient numbers and radiotherapy treatment planning procedures and performances at all Austrian radiotherapy institutes. Results were correlated with incidence rates (Austrian cancer registry) to determine patterns of radiotherapy practice in Austria. At 12 radiotherapy departments of Austria data of all patients receiving irradiation within a 3 months (2002/2003) period were assessed. On the basis of a questionnaire number of treated patients, indications, and parameters of disease (stage, histology) and treatment modalities were evaluated. Results were analysed with regard to different tumour groups, according to academic and non academic hospitals, and correlated with epidemiological data on cancer incidence. In total, 3783 patients were registered within this period. According to the different tumour entities percentages of patients receiving radiotherapy within initial treatment varied from 3% to 90 % (e.g. brain tumours: 77%, breast cancer: 90%, prostate cancer: 35%). The most frequent indications to radiotherapy per radiotherapy department were breast cancer (range 22%-35%; mean 26%), urological tumours (range 6%-27%; mean 12%) and bone metastases (mean 10%, range 3%-17%). In Austria breast cancer, urological tumours and bone metastases are representing the most common indications to radiotherapy. Among the different departments variations in indications to radiotherapy were observed. Our study is the first evaluation of radiotherapeutic management in Austria.

Precise automatic differential stellar photometry

NASA Technical Reports Server (NTRS)

Young, Andrew T.; Genet, Russell M.; Boyd, Louis J.; Borucki, William J.; Lockwood, G. Wesley

1991-01-01

The factors limiting the precision of differential stellar photometry are reviewed. Errors due to variable atmospheric extinction can be reduced to below 0.001 mag at good sites by utilizing the speed of robotic telescopes. Existing photometric systems produce aliasing errors, which are several millimagnitudes in general but may be reduced to about a millimagnitude in special circumstances. Conventional differential photometry neglects several other important effects, which are discussed in detail. If all of these are properly handled, it appears possible to do differential photometry of variable stars with an overall precision of 0.001 mag with ground based robotic telescopes.

Precision gas therapy using intelligent nanomedicine.

PubMed

He, Qianjun

2017-10-24

Gas therapy is an emerging and promising field, utilizing the unique therapeutic effects of several kinds of gases (NO, CO, H 2 S and H 2 ) towards many major diseases, including cancer and cardiovascular diseases, and it is also facing challenges relating to enhancing gas therapy efficacy and avoiding gas poisoning risks. Here, we have proposed a new concept for precision gas therapy using a nanomedicine strategy to overcome the challenges. In this perspective, we have addressed a series of existing and potential solutions from the point of view of nanomedicine, and conveyed a collection of opinions about future expandable research into precision gas therapy.

Complement is a central mediator of radiotherapy-induced tumor-specific immunity and clinical response.

PubMed

Surace, Laura; Lysenko, Veronika; Fontana, Andrea Orlando; Cecconi, Virginia; Janssen, Hans; Bicvic, Antonela; Okoniewski, Michal; Pruschy, Martin; Dummer, Reinhard; Neefjes, Jacques; Knuth, Alexander; Gupta, Anurag; van den Broek, Maries

2015-04-21

Radiotherapy induces DNA damage and cell death, but recent data suggest that concomitant immune stimulation is an integral part of the therapeutic action of ionizing radiation. It is poorly understood how radiotherapy supports tumor-specific immunity. Here we report that radiotherapy induced tumor cell death and transiently activated complement both in murine and human tumors. The local production of pro-inflammatory anaphylatoxins C3a and C5a was crucial to the tumor response to radiotherapy and concomitant stimulation of tumor-specific immunity. Dexamethasone, a drug frequently given during radiotherapy, limited complement activation and the anti-tumor effects of the immune system. Overall, our findings indicate that anaphylatoxins are key players in radiotherapy-induced tumor-specific immunity and the ensuing clinical responses. Copyright © 2015 Elsevier Inc. All rights reserved.

Voice quality after endoscopic laser surgery and radiotherapy for early glottic cancer: objective measurements emphasizing the Voice Handicap Index

PubMed Central

Caminero Cueva, Maria Jesús; Señaris González, Blanca; Llorente Pendás, José Luis; Gorriz Gil, Carmen; López Llames, Aurora; Alonso Pantiga, Ramón; Suárez Nieto, Carlos

2007-01-01

We analyzed the functional outcome and self-evaluation of the voice of patients with T1 glottic carcinoma treated with endoscopic laser surgery and radiotherapy. We performed an objective voice evaluation, as well as a physical, emotional and functional well being assessment of 19 patients treated with laser surgery and 18 patients treated with radiotherapy. Voice quality is affected both by surgery and radiotherapy. Voice parameters only show differences in the maximum phonation time between both treatments. Results in the Voice Handicap Index show that radiotherapy has less effect on patient voice quality perception. There is a reduced impact on the patient’s perception of voice quality after radiotherapy, despite there being no significant differences in vocal quality between radiotherapy and laser cordectomy. PMID:17999074

Reirradiation for recurrent head and neck cancers using charged particle or photon radiotherapy.

PubMed

Yamazaki, Hideya; Demizu, Yusuke; Okimoto, Tomoaki; Ogita, Mikio; Himei, Kengo; Nakamura, Satoaki; Suzuki, Gen; Yoshida, Ken; Kotsuma, Tadayuki; Yoshioka, Yasuo; Oh, Ryoongjin

2017-07-01

To examine the outcomes of reirradiation for recurrent head and neck cancers using different modalities. This retrospective study included 26 patients who received charged particle radiotherapy (CP) and 150 who received photon radiotherapy (117 CyberKnife radiotherapy [CK] and 36 intensity-modulated radiotherapy [IMRT]). Inverse probability of treatment weighting (IPTW) involving propensity scores was used to reduce background selection bias. Higher prescribed doses were used in CP than photon radiotherapy. The 1‑year overall survival (OS) rates were 67.9% for CP and 54.1% for photon radiotherapy (p = 0.15; 55% for CK and 51% for IMRT). In multivariate Cox regression, the significant prognostic factors for better survival were nasopharyngeal cancer, higher prescribed dose, and lower tumor volume. IPTW showed a statistically significant difference between CP and photon radiotherapy (p = 0.04). The local control rates for patients treated with CP and photon radiotherapy at 1 year were 66.9% (range 46.3-87.5%) and 67.1% (range 58.3-75.9%), respectively. A total of 48 patients (27%) experienced toxicity grade ≥3 (24% in the photon radiotherapy group and 46% in the CP group), including 17 patients with grade 5 toxicity. Multivariate analysis revealed that younger age and a larger planning target volume (PTV) were significant risk factors for grade 3 or worse toxicity. CP provided superior survival outcome compared to photon radiotherapy. Tumor volume, primary site (nasopharyngeal), and prescribed dose were identified as survival factors. Younger patients with a larger PTV experienced toxicity grade ≥3.

Radiotherapy for esthesioneuroblastoma: is elective nodal irradiation warranted in the multimodality treatment approach?

PubMed

Noh, O Kyu; Lee, Sang-wook; Yoon, Sang Min; Kim, Sung Bae; Kim, Sang Yoon; Kim, Chang Jin; Jo, Kyung Ja; Choi, Eun Kyung; Song, Si Yeol; Kim, Jong Hoon; Ahn, Seung Do

2011-02-01

The role of elective nodal irradiation (ENI) in radiotherapy for esthesioneuroblastoma (ENB) has not been clearly defined. We analyzed treatment outcomes of patients with ENB and the frequency of cervical nodal failure in the absence of ENI. Between August 1996 and December 2007, we consulted with 19 patients with ENB regarding radiotherapy. Initial treatment consisted of surgery alone in 2 patients; surgery and postoperative radiotherapy in 4; surgery and adjuvant chemotherapy in 1; surgery, postoperative radiotherapy, and chemotherapy in 3; and chemotherapy followed by radiotherapy or concurrent chemoradiotherapy in 5. Five patients did not receive planned radiotherapy because of disease progression. Including 2 patients who received salvage radiotherapy, 14 patients were treated with radiotherapy. Elective nodal irradiation was performed in 4 patients with high-risk factors, including 3 with cervical lymph node metastasis at presentation. Fourteen patients were analyzable, with a median follow-up of 27 months (range, 7-64 months). The overall 3-year survival rate was 73.4%. Local failure occurred in 3 patients (21.4%), regional cervical failure in 3 (21.4%), and distant failure in 2 (14.3%). No cervical nodal failure occurred in patients treated with combined systemic chemotherapy regardless of ENI. Three cervical failures occurred in the 4 patients treated with ENI or neck dissection (75%), none of whom received systemic chemotherapy. ENI during radiotherapy for ENB seems to play a limited role in preventing cervical nodal failure. Omitting ENI may be an option if patients are treated with a combination of radiotherapy and chemotherapy. Copyright © 2011 Elsevier Inc. All rights reserved.

A phase match based frequency estimation method for sinusoidal signals

NASA Astrophysics Data System (ADS)

Shen, Yan-Lin; Tu, Ya-Qing; Chen, Lin-Jun; Shen, Ting-Ao

2015-04-01

Accurate frequency estimation affects the ranging precision of linear frequency modulated continuous wave (LFMCW) radars significantly. To improve the ranging precision of LFMCW radars, a phase match based frequency estimation method is proposed. To obtain frequency estimation, linear prediction property, autocorrelation, and cross correlation of sinusoidal signals are utilized. The analysis of computational complex shows that the computational load of the proposed method is smaller than those of two-stage autocorrelation (TSA) and maximum likelihood. Simulations and field experiments are performed to validate the proposed method, and the results demonstrate the proposed method has better performance in terms of frequency estimation precision than methods of Pisarenko harmonic decomposition, modified covariance, and TSA, which contribute to improving the precision of LFMCW radars effectively.

Review: Milking robot utilization, a successful precision livestock farming evolution.

PubMed

John, A J; Clark, C E F; Freeman, M J; Kerrisk, K L; Garcia, S C; Halachmi, I

2016-09-01

Automatic milking systems (AMS), one of the earliest precision livestock farming developments, have revolutionized dairy farming around the world. While robots control the milking process, there have also been numerous changes to how the whole farm system is managed. Milking is no longer performed in defined sessions; rather, the cow can now choose when to be milked in AMS, allowing milking to be distributed throughout a 24 h period. Despite this ability, there has been little attention given to milking robot utilization across 24 h. In order to formulate relevant research questions and improve farm AMS management there is a need to determine the current knowledge gaps regarding the distribution of robot utilization. Feed, animal and management factors and their interplay on levels of milking robot utilization across 24 h for both indoor and pasture-based systems are here reviewed. The impact of the timing, type and quantity of feed offered and their interaction with the distance of feed from the parlour; herd social dynamics, climate and various other management factors on robot utilization through 24 h are provided. This novel review draws together both the opportunities and challenges that exist for farm management to use these factors to improved system efficiency and those that exist for further research.

Enraged about radiotherapy.

PubMed Central

Sikora, K.

1994-01-01

The use of radiotherapy in treating breast cancer has meant that many women are able to avoid mastectomy, which is both physically and psychologically damaging. The side effects of radiotherapy, however, are given little attention. Many women have developed brachial plexus injury after radiotherapy for breast cancer, often resulting in severe pain and loss of use of the arm. There is no effective treatment for this injury and little help can be offered. In addition, many of the women did not require radiotherapy of nodal areas. A pressure group has been formed to support these women, to establish the right to compensation, and to ensure that radiotherapy regimens given to future patients will not damage the brachial plexus. Images p188-a PMID:8312773

SU-F-T-681: Does the Biophysical Modeling for Immunological Aspects in Radiotherapy Precisely Predict Tumor and Normal Tissue Responses?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oita, M; Nakata, K; Sasaki, M

2016-06-15

Purpose: Recent advances in immunotherapy make possible to combine with radiotherapy. The aim of this study was to assess the TCP/NTCP model with immunological aspects including stochastic distribution as intercellular uncertainties. Methods: In the clinical treatment planning system (Eclipse ver.11.0, Varian medical systems, US), biological parameters such as α/β, D50, γ, n, m, TD50 including repair parameters (bi-exponential repair) can be set as any given values to calculate the TCP/NTCP. Using a prostate cancer patient data with VMAT commissioned as a 6-MV photon beam of Novalis-Tx (BrainLab, US) in clinical use, the fraction schedule were hypothesized as 70–78Gy/35–39fr, 72–81Gy/40–45fr, 52.5–66Gy/16–22fr,more » 35–40Gy/5fr of 5–7 fractions in a week. By use of stochastic biological model applying for Gaussian distribution, the effects of the TCP/NTCP variation of repair parameters of the immune system as well as the intercellular uncertainty of tumor and normal tissues have been evaluated. Results: As respect to the difference of the α/β, the changes of the TCP/NTCP were increased in hypo-fraction regimens. The difference between the values of n and m affect the variation of the NTCP with the fraction schedules, independently. The elongation of repair half-time (long) increased the TCP/NTCP twice or much higher in the case of hypo-fraction scheme. For tumor, the repopulation parameters such as Tpot and Tstart, which is immunologically working to the tumor, improved TCP. Conclusion: Compared to default fixed value, which has affected by the probability of cell death and cure, hypo-fractionation schemes seemed to have advantages for the variations of the values of m. The possibility of an increase of the α/β or TD50 and repair parameters in tumor and normal tissue by immunological aspects were highly expected. For more precise prediction, treatment planning systems should be incorporated the complicated biological optimization in clinical practice combined with basic experiments data.« less

Portable and wide-range solid-state transmission densitometer for quality control in film radiography

PubMed Central

Aramburo, Javier Morales; Gonzalez, Sigifredo Solano; Toledo, Jorge Toledo

2010-01-01

In biology, materials science, radiography quality control or film dosimetry in radiotherapy, a transmission densitometer is useful for measurements of optical density. The design proposed here is oriented to quality control in radiographic films. The instrument described here utilizes low-cost solid-state devices and is easy to construct. The use of 1-watt white light-emitting diode in this densitometer enables low power consumption and a cold light source. Moreover, the instrument does not need a reference light, which results in decreasing the number of parts and reducing the overall size of the apparatus. PMID:20927222

Strategies for Translating Evidence-Based Medicine in Lung Cancer into Community Practice.

PubMed

Rosenberg, Stephen A; Baschnagel, Andrew M; Bagley, Stephen J; Housri, Nadine

2017-01-01

The landscape of non-small cell lung cancer (NSCLC) treatment has rapidly evolved over the past decade. This is exemplified by the use of molecular targeted agents, immunotherapies, and newer technologies such as stereotactic body radiotherapy (SBRT). As the translation of preclinical discoveries into clinical practice continues, the effective dissemination and implementation of evidence-based treatment of NSCLC will remain a foremost challenge for oncologists. To further extend evidence-based medicine into the community setting, community oncologists are being engaged on multiple fronts including leadership and participation in national clinical trials and utilization of internet-based resources.

Numerical simulations for tumor and cellular immune system interactions in lung cancer treatment

NASA Astrophysics Data System (ADS)

Kolev, M.; Nawrocki, S.; Zubik-Kowal, B.

2013-06-01

We investigate a new mathematical model that describes lung cancer regression in patients treated by chemotherapy and radiotherapy. The model is composed of nonlinear integro-differential equations derived from the so-called kinetic theory for active particles and a new sink function is investigated according to clinical data from carcinoma planoepitheliale. The model equations are solved numerically and the data are utilized in order to find their unknown parameters. The results of the numerical experiments show a good correlation between the predicted and clinical data and illustrate that the mathematical model has potential to describe lung cancer regression.

Do Circulating Tumor Cells, Exosomes, and Circulating Tumor Nucleic Acids Have Clinical Utility?

PubMed Central

Gold, Bert; Cankovic, Milena; Furtado, Larissa V.; Meier, Frederick; Gocke, Christopher D.

2016-01-01

Diagnosing and screening for tumors through noninvasive means represent an important paradigm shift in precision medicine. In contrast to tissue biopsy, detection of circulating tumor cells (CTCs) and circulating tumor nucleic acids provides a minimally invasive method for predictive and prognostic marker detection. This allows early and serial assessment of metastatic disease, including follow-up during remission, characterization of treatment effects, and clonal evolution. Isolation and characterization of CTCs and circulating tumor DNA (ctDNA) are likely to improve cancer diagnosis, treatment, and minimal residual disease monitoring. However, more trials are required to validate the clinical utility of precise molecular markers for a variety of tumor types. This review focuses on the clinical utility of CTCs and ctDNA testing in patients with solid tumors, including somatic and epigenetic alterations that can be detected. A comparison of methods used to isolate and detect CTCs and some of the intricacies of the characterization of the ctDNA are also provided. PMID:25908243

Assessment of Gamma-Ray-Spectra Analysis Method Utilizing the Fireworks Algorithm for Various Error Measures

DOE PAGES

Alamaniotis, Miltiadis; Tsoukalas, Lefteri H.

2018-01-01

The analysis of measured data plays a significant role in enhancing nuclear nonproliferation mainly by inferring the presence of patterns associated with special nuclear materials. Among various types of measurements, gamma-ray spectra is the widest utilized type of data in nonproliferation applications. In this paper, a method that employs the fireworks algorithm (FWA) for analyzing gamma-ray spectra aiming at detecting gamma signatures is presented. In particular, FWA is utilized to fit a set of known signatures to a measured spectrum by optimizing an objective function, where non-zero coefficients express the detected signatures. FWA is tested on a set of experimentallymore » obtained measurements optimizing various objective functions—MSE, RMSE, Theil-2, MAE, MAPE, MAP—with results exhibiting its potential in providing highly accurate and precise signature detection. Finally and furthermore, FWA is benchmarked against genetic algorithms and multiple linear regression, showing its superiority over those algorithms regarding precision with respect to MAE, MAPE, and MAP measures.« less

Precision and sensitivity of the measurement of 15N enrichment in D-alanine from bacterial cell walls using positive/negative ion mass spectrometry

NASA Technical Reports Server (NTRS)

Tunlid, A.; Odham, G.; Findlay, R. H.; White, D. C.

1985-01-01

Sensitive detection of cellular components from specific groups of microbes can be utilized as 'signatures' in the examination of microbial consortia from soils, sediments or biofilms. Utilizing capillary gas chromatography/mass spectrometry and stereospecific derivatizing agents, D-alanine, a component localized in the prokaryotic (bacterial) cell wall, can be detected reproducibly. Enrichments of D-[15N]alanine determined in E. coli grown with [15N]ammonia can be determined with precision at 1.0 atom%. Chemical ionization with methane gas and the detection of negative ions (M - HF)- and (M - F or M + H - HF)- formed from the heptafluorobutyryl D-2 butanol ester of D-alanine allowed as little as 8 pg (90 fmol) to be detected reproducibly. This method can be utilized to define the metabolic activity in terms of 15N incorporation at the level of 10(3)-10(4) cells, as a function of the 15N-14N ratio.

Updates on clinical studies of selenium supplementation in radiotherapy

PubMed Central

2014-01-01

To establish guidelines for the selenium supplementation in radiotherapy we assessed the benefits and risks of selenium supplementation in radiotherapy. Clinical studies on the use of selenium in radiotherapy were searched in the PubMed electronic database in January 2013. Sixteen clinical studies were identified among the 167 articles selected in the initial search. Ten articles were observational studies, and the other 6 articles reported studies on the effects of selenium supplementation in patients with cancer who underwent radiotherapy. The studies were conducted worldwide including European, American and Asian countries between 1987 and 2012. Plasma, serum or whole blood selenium levels were common parameters used to assess the effects of radiotherapy and the selenium supplementation status. Selenium supplementation improved the general conditions of the patients, improved their quality of life and reduced the side effects of radiotherapy. At the dose of selenium used in these studies (200–500 μg/day), selenium supplementation did not reduce the effectiveness of radiotherapy, and no toxicities were reported. Selenium supplementation may offer specific benefits for several types of cancer patients who undergo radiotherapy. Because high-dose selenium and long-term supplementation may be unsafe due to selenium toxicity, more evidence-based information and additional research are needed to ensure the therapeutic benefits of selenium supplementation. PMID:24885670

Is it possible to improve communication around radiotherapy delivery: A randomized study to assess the efficacy of team training?

PubMed

Liénard, Aurore; Delevallez, France; Razavi, Darius; Gibon, Anne-Sophie; Libert, Yves; Delvaux, Nicole; Marchal, Serge; Etienne, Anne-Marie; Bragard, Isabelle; Reynaert, Christine; Slachmuylder, Jean-Louis; Durieux, Jean-François; Farvacques, Christine; Scalliet, Pierre; Van Houtte, Paul; Coucke, Philippe; Merckaert, Isabelle

2016-05-01

The aim of this study was to assess the efficacy of a 38-h communication skills training program designed for multidisciplinary radiotherapy teams. Four radiotherapy teams were randomly assigned to a training program or to a waiting list. Assessments were scheduled at baseline (T1) and then after the training was completed or four months later (T2), respectively. Communication around radiotherapy delivery was assessed based on audio recordings of the first and last radiotherapy sessions in order to assess team members' communication skills and the expression of concerns by breast cancer patients (analyzed with content analysis software LaComm). 198 radiotherapy sessions were recorded. During the first radiotherapy sessions, members of the trained teams exhibited more assessment skills (p=0.048), provided more setting information (p<0.001), and used more social words (p=0.019) compared to the members of the untrained teams. During the last radiotherapy session, members of the trained teams used more assessment skills (p=0.004) and patients interacting with members of the trained teams expressed more sadness words (p=0.023). Training of multidisciplinary teams has the potential to transfer skills that affect the short exchanges that take place around radiotherapy delivery. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Fabrication of three-dimensional scaffolds using precision extrusion deposition with an assisted cooling device.

PubMed

Hamid, Q; Snyder, J; Wang, C; Timmer, M; Hammer, J; Guceri, S; Sun, W

2011-09-01

In the field of biofabrication, tissue engineering and regenerative medicine, there are many methodologies to fabricate a building block (scaffold) which is unique to the target tissue or organ that facilitates cell growth, attachment, proliferation and/or differentiation. Currently, there are many techniques that fabricate three-dimensional scaffolds; however, there are advantages, limitations and specific tissue focuses of each fabrication technique. The focus of this initiative is to utilize an existing technique and expand the library of biomaterials which can be utilized to fabricate three-dimensional scaffolds rather than focusing on a new fabrication technique. An expanded library of biomaterials will enable the precision extrusion deposition (PED) device to construct three-dimensional scaffolds with enhanced biological, chemical and mechanical cues that will benefit tissue generation. Computer-aided motion and extrusion drive the PED to precisely fabricate micro-scaled scaffolds with biologically inspired, porosity, interconnectivity and internal and external architectures. The high printing resolution, precision and controllability of the PED allow for closer mimicry of tissues and organs. The PED expands its library of biopolymers by introducing an assisting cooling (AC) device which increases the working extrusion temperature from 120 to 250 °C. This paper investigates the PED with the integrated AC's capabilities to fabricate three-dimensional scaffolds that support cell growth, attachment and proliferation. Studies carried out in this paper utilized a biopolymer whose melting point is established to be 200 °C. This polymer was selected to illustrate the newly developed device's ability to fabricate three-dimensional scaffolds from a new library of biopolymers. Three-dimensional scaffolds fabricated with the integrated AC device should illustrate structural integrity and ability to support cell attachment and proliferation.

Efficacy of low-dose radiotherapy in painful gonarthritis: experiences from a retrospective East German bicenter study

PubMed Central

2013-01-01

Purpose To evaluate the efficacy of low-dose radiotherapy in painful gonarthritis. Methods We assessed the medical records of 1037 patients with painful gonarthritis who had undergone low-dose radiotherapy between 1981 and 2008. The subjective patient perception of the response to irradiation as graded immediately or up to two months after the completion of a radiotherapy series was evaluated and correlated with age, gender, radiological grading and the duration of symptoms before radiotherapy. Moreover, we performed a mail survey to obtain additional long-term follow-up information and received one hundred and six evaluable questionnaires. Results We assessed 1659 series of radiotherapy in 1037 patients. In 79.3% of the cases the patients experienced a slight, marked or complete pain relief immediately or up to two months after the completion of radiotherapy. Gender, age and the duration of pain before radiotherapy did not have a significant influence on the response to irradiation. In contrast, severe signs of osteoarthritis were associated with more effective pain relief. In more than 50% of the patients who reported a positive response to irradiation a sustained period of symptomatic improvement was observed. Conclusions Our results confirm that low-dose radiotherapy is an effective treatment for painful osteoarthritis of the knee. In contrast to an earlier retrospective study, severe signs of osteoarthritis constituted a positive prognostic factor for the response to irradiation. A randomized trial is urgently required to compare radiotherapy with other treatment modalities. PMID:23369282

Seizure control following radiotherapy in patients with diffuse gliomas: a retrospective study

PubMed Central

Rudà, Roberta; Magliola, Umberto; Bertero, Luca; Trevisan, Elisa; Bosa, Chiara; Mantovani, Cristina; Ricardi, Umberto; Castiglione, Anna; Monagheddu, Chiara; Soffietti, Riccardo

2013-01-01

Background Little information is available regarding the effect of conventional radiotherapy on glioma-related seizures. Methods In this retrospective study, we analyzed the seizure response and outcome following conventional radiotherapy in a cohort of 43 patients with glioma (33 grade II, 10 grade III) and medically intractable epilepsy. Results At 3 months after radiotherapy, seizure reduction was significant (≥50% reduction of frequency compared with baseline) in 31/43 patients (72%) of the whole series and in 25/33 patients (76%) with grade II gliomas, whereas at 12 months seizure reduction was significant in 26/34 (76%) and in 19/25 (76%) patients, respectively. Seizure reduction was observed more often among patients displaying an objective tumor response on MRI, but patients with no change on MRI also had a significant seizure reduction. Seizure freedom (Engel class I) was achieved at 12 months in 32% of all patients and in 38% of patients with grade II tumors. Timing of radiotherapy and duration of seizures prior to radiotherapy were significantly associated with seizure reduction. Conclusions This study showed that a high proportion of patients with medically intractable epilepsy from diffuse gliomas derive a significant and durable benefit from radiotherapy in terms of epilepsy control and that this positive effect is not strictly associated with tumor shrinkage as shown on MRI. Radiotherapy at tumor progression seems as effective as early radiotherapy after surgery. Prospective studies must confirm and better characterize the response to radiotherapy. PMID:23897633

The anal canal as a risk organ in cervical cancer patients with hemorrhoids undergoing whole pelvic radiotherapy.

PubMed

Jang, Hyunsoo; Baek, Jong Geun; Jo, Sunmi

2015-01-01

Tolerance of the anal canal tends to be ignored in patients with cervical cancer undergoing whole pelvic radiotherapy. However, patients with hemorrhoids may be troubled with low radiation dose. We tried to analyze the dose-volume statistics of the anal canal in patients undergoing whole pelvic radiotherapy. The records of 31 patients with cervical cancer who received definite or postoperative radiotherapy at one institution were reviewed. Acute anal symptoms, such as anal pain and bleeding, were evaluated from radiotherapy start to 1 month after radiotherapy completion. Various clinical and dosimetric factors were analyzed to characterize relations with acute anal complications. The anal verge was located an average of 1.2 cm (range -0.6~3.9) below the lower border of the ischial tuberosity and an average of 2.7 cm (range -0.6~5.7) behind the sacral promontory level. The presence of hemorrhoids before radiotherapy was found to be significantly associated with acute radiation-induced anal symptoms (p = 0.001), and the mean induction dose for anal symptoms was 36.9 Gy. No patient without hemorrhoids developed an anal symptom during radiotherapy. Dosimetric analyses of V30 and V40 showed marginal correlations with anal symptoms (p = 0.07). The present study suggests a relation between acute anal symptoms following radiotherapy and acute hemorrhoid aggravation. Furthermore, the location of the anal verge was found to be variable, and consequently doses administered to the anal canal also varied substantially. Our results caution careful radiation treatment planning for whole pelvic radiotherapy, and that proper clinical management be afforded patients with hemorrhoids during radiotherapy.

Associations between nutritional status, weight loss, radiotherapy treatment toxicity and treatment outcomes in gastrointestinal cancer patients.

PubMed

Hill, Amanda; Kiss, Nicole; Hodgson, Belinda; Crowe, Timothy C; Walsh, Adam D

2011-02-01

Patients with gastrointestinal cancers are susceptible to nutritional deterioration which may be compounded by radiotherapy treatment toxicities. This study aimed to determine whether nutritional status at radiotherapy commencement or changes in nutritional status throughout radiotherapy were associated with treatment toxicity and outcomes in gastrointestinal cancer patients. Seventy-three gastrointestinal cancer patients receiving curative radiotherapy underwent medical record audits assessing body weight, radiotherapy toxicity, unplanned treatment breaks or hospital admissions and completion of prescribed treatment/s. Nutritional status was assessed in a subset of patients (n = 11) using the Patient-Generated Subjective Global Assessment tool. Seventy-five percent of patients lost weight throughout radiotherapy. Weight loss was significantly greater in patients experiencing unplanned radiotherapy breaks (-3.1% vs -1.6%, p < 0.05) and in patients not completing prescribed chemotherapy (-3.3% vs -1.6%, p < 0.05). Toxicity severity was strongly correlated with Patient-Generated Subjective Global Assessment score (rho = 0.839, p < 0.001) and was increased in patients experiencing unplanned admissions compared to those without admission (42.1% vs 9.3% with grade 3 toxicity respectively, p < 0.001). Deterioration in nutritional status during radiotherapy (as measured by weight loss) may be associated with poorer short-term treatment outcomes in gastrointestinal cancer patients. Patient numbers were too small to definitively determine the effect of nutritional status at radiotherapy commencement or changes in nutritional status throughout radiotherapy (defined by PG-SGA) on treatment outcomes. Further research is required to investigate this in larger, longer-term studies. Copyright © 2010. Published by Elsevier Ltd.

Contribution of FDOPA PET to radiotherapy planning for advanced glioma

NASA Astrophysics Data System (ADS)

Dowson, Nicholas; Fay, Michael; Thomas, Paul; Jeffree, Rosalind; McDowall, Robert; Winter, Craig; Coulthard, Alan; Smith, Jye; Gal, Yaniv; Bourgeat, Pierrick; Salvado, Olivier; Crozier, Stuart; Rose, Stephen

2014-03-01

Despite radical treatment with surgery, radiotherapy and chemotherapy, advanced gliomas recur within months. Geographic misses in radiotherapy planning may play a role in this seemingly ineluctable recurrence. Planning is typically performed on post-contrast MRIs, which are known to underreport tumour volume relative to FDOPA PET scans. FDOPA PET fused with contrast enhanced MRI has demonstrated greater sensitivity and specificity than MRI alone. One sign of potential misses would be differences between gross target volumes (GTVs) defined using MRI alone and when fused with PET. This work examined whether such a discrepancy may occur. Materials and Methods: For six patients, a 75 minute PET scan using 3,4-dihydroxy-6-18F-fluoro-L-phynel-alanine (18F-FDOPA) was taken within 2 days of gadolinium enhanced MRI scans. In addition to standard radiotherapy planning by an experienced radiotherapy oncologist, a second gross target volume (GTV) was defined by an experienced nuclear medicine specialist for fused PET and MRI, while blinded to the radiotherapy plans. The volumes from standard radiotherapy planning were compared to the PET defined GTV. Results: The comparison indicated radiotherapy planning would change in several cases if FDOPA PET data was available. PET-defined contours were external to 95% prescribed dose for several patients. However, due to the radiotherapy margins, the discrepancies were relatively small in size and all received a dose of 50 Gray or more. Conclusions: Given the limited size of the discrepancies it is uncertain that geographic misses played a major role in patient outcome. Even so, the existence of discrepancies indicates that FDOPA PET could assist in better defining margins when planning radiotherapy for advanced glioma, which could be important for highly conformal radiotherapy plans.

Cardiac Side-effects From Breast Cancer Radiotherapy.

PubMed

Taylor, C W; Kirby, A M

2015-11-01

Breast cancer radiotherapy reduces the risk of cancer recurrence and death. However, it usually involves some radiation exposure of the heart and analyses of randomised trials have shown that it can increase the risk of heart disease. Estimates of the absolute risks of radiation-related heart disease are needed to help oncologists plan each individual woman's treatment. The risk for an individual woman varies according to her estimated cardiac radiation dose and her background risk of ischaemic heart disease in the absence of radiotherapy. When it is known, this risk can then be compared with the absolute benefit of the radiotherapy. At present, many UK cancer centres are already giving radiotherapy with mean heart doses of less than 3 Gy and for most women the benefits of the radiotherapy will probably far outweigh the risks. Technical approaches to minimising heart dose in breast cancer radiotherapy include optimisation of beam angles, use of multileaf collimator shielding, intensity-modulated radiotherapy, treatment in a prone position, treatment in deep inspiration (including the use of breath-hold and gating techniques), proton therapy and partial breast irradiation. The multileaf collimator is suitable for many women with upper pole left breast cancers, but for women with central or lower pole cancers, breath-holding techniques are now recommended in national UK guidelines. Ongoing work aims to identify ways of irradiating pan-regional lymph nodes that are effective, involve minimal exposure of organs at risk and are feasible to plan, deliver and verify. These will probably include wide tangent-based field-in-field intensity-modulated radiotherapy or arc radiotherapy techniques in combination with deep inspiratory breath-hold, and proton beam irradiation for women who have a high predicted heart dose from intensity-modulated radiotherapy. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

The use of adjuvant radiotherapy in elderly patients with early-stage breast cancer: changes in practice patterns after publication of Cancer and Leukemia Group B 9343.

PubMed

Palta, Manisha; Palta, Priya; Bhavsar, Nrupen A; Horton, Janet K; Blitzblau, Rachel C

2015-01-15

The Cancer and Leukemia Group B (CALGB) 9343 randomized phase 3 trial established lumpectomy and adjuvant therapy with tamoxifen alone, rather than both radiotherapy and tamoxifen, as a reasonable treatment course for women aged >70 years with clinical stage I (AJCC 7th edition), estrogen receptor-positive breast cancer. An analysis of the Surveillance, Epidemiology, and End Results (SEER) registry was undertaken to assess practice patterns before and after the publication of this landmark study. The SEER database from 2000 to 2009 was used to identify 40,583 women aged ≥70 years who were treated with breast-conserving surgery for clinical stage I, estrogen receptor-positive and/or progesterone receptor-positive breast cancer. The percentage of patients receiving radiotherapy and the type of radiotherapy delivered was assessed over time. Administration of radiotherapy was further assessed across age groups; SEER cohort; and tumor size, grade, and laterality. Approximately 68.6% of patients treated between 2000 and 2004 compared with 61.7% of patients who were treated between 2005 and 2009 received some form of adjuvant radiotherapy (P < .001). Coinciding with a decline in the use of external beam radiotherapy, there was an increase in the use of implant radiotherapy from 1.4% between 2000 and 2004 to 6.2% between 2005 to 2009 (P < .001). There were significant reductions in the frequency of radiotherapy delivery over time across age groups, tumor size, and tumor grade and regardless of laterality (P < .001 for all). Randomized phase 3 data support the omission of adjuvant radiotherapy in elderly women with early-stage breast cancer. Analysis of practice patterns before and after the publication of these data indicates a significant decline in radiotherapy use; however, nearly two-thirds of women continue to receive adjuvant radiotherapy. © 2014 American Cancer Society.

Effectiveness of Radiotherapy for Elderly Patients With Glioblastoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, Jacob; Tsai, Ya-Yu; Chinnaiyan, Prakash

Purpose: Radiotherapy plays a central role in the definitive treatment of glioblastoma. However, the optimal management of elderly patients with glioblastoma remains controversial, as the relative benefit in this patient population is unclear. To better understand the role that radiation plays in the treatment of glioblastoma in the elderly, we analyzed factors influencing patient survival using a large population-based registry. Methods and Materials: A total of 2,836 patients more than 70 years of age diagnosed with glioblastoma between 1993 and 2005 were identified from the Surveillance, Epidemiology, and End Results (SEER) registry. Demographic and clinical variables used in the analysismore » included gender, ethnicity, tumor size, age at diagnosis, surgery, and radiotherapy. Cancer-specific survival and overall survival were evaluated using the Kaplan-Meier method. Univariate and multivariate analysis were performed using Cox regression. Results: Radiotherapy was administered in 64% of these patients, and surgery was performed in 68%. Among 2,836 patients, 46% received surgery and radiotherapy, 22% underwent surgery only, 18% underwent radiotherapy only, and 14% did not undergo either treatment. The median survival for patients who underwent surgery and radiotherapy was 8 months. The median survival for patients who underwent radiotherapy only was 4 months, and for patients who underwent surgery only was 3 months. Those who received neither surgery nor radiotherapy had a median survival of 2 months (p < 0.001). Multivariate analysis showed that radiotherapy significantly improved cancer-specific survival (hazard ratio [HR], 0.43, 95% confidence interval [CI] 0.38-0.49) after adjusting for surgery, tumor size, gender, ethnicity, and age at diagnosis. Other factors associated with Cancer-specific survival included surgery, tumor size, age at diagnosis, and ethnicity. Analysis using overall survival as the endpoint yielded very similar results. Conclusions: Elderly patients with glioblastoma who underwent radiotherapy had improved cancer-specific survival and overall survival compared to patients who did not receive radiotherapy.« less

[Radiotherapy in cancers of the oesophagus, the gastric cardia and the stomach].

PubMed

Créhange, G; Huguet, F; Quero, L; N'Guyen, T V; Mirabel, X; Lacornerie, T

2016-09-01

Localized oesophageal and gastric cancers have a poor prognosis. In oesophageal cancer, external radiotherapy combined with concomitant chemotherapy is accepted as part of the therapeutic armamentarium in a curative intent in the preoperative setting for resectable tumours; or without surgery in inoperable patients or non-resectable tumours due to wide local and/or regional extension. Data from the literature show conflicting results with no clinical evidence in favour of either a unique dose protocol or consensual target volume definition in the setting of exclusive chemoradiation. In the preoperative setting, chemoradiotherapy has become the standard in oesophageal cancer, even though there is no evidence that surgery may be beneficial in locally advanced tumours that respond to radiotherapy and chemotherapy. The main cause of failure after exclusive chemoradiotherapy in oesophageal cancer is locoregional relapse suggesting that doses and volumes usually considered may be inadequate. In gastric cancer, radiotherapy may be indicated postoperatively in patients with resected tumours that include less than D2 lymph node dissection or in the absence of perioperative chemotherapy. Preoperative chemoradiotherapy in gastric cancers is still under investigation. The evolving techniques of external radiotherapy, such as image-guided radiotherapy (IMRT) and volumetric modulated arctherapy (VMAT) have reduced the volume of lung and heart exposed to radiation, which seems to have diminished radiotherapy-related morbi-mortality rates. Given this, quality assurance for radiotherapy and protocols for radiotherapy delivery must be better standardized. This article on the indications for radiotherapy and the techniques used in oesophageal and gastric cancers is included in a special issue dedicated to national recommendations from the French society of radiation oncology (SFRO) on radiotherapy indications, planning, dose prescription, and techniques of radiotherapy delivery. Copyright © 2016 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

Precision of Times-of-Minima and the Detection of Low-Mass Third Bodies Orbiting Eclipsing Binaries

NASA Astrophysics Data System (ADS)

Genet, R. M.; Smith, T. C.

2004-12-01

Low-mass third bodies orbiting eclipsing binaries are difficult to detect by way of periodic shifts in photometric times-of-minima because the observational precision of these timings are of the same order as the expected effects of any low-mass companions. We are implementing three approaches to increasing the precision of our times-of-minima. First, we are obtaining many times-of-minima by utilizing relatively low-cost, dedicated telescopes and CCD cameras (10- and 14-inch Meade LX-200 telescopes and SBIG ST7-XE cameras). Operating in a semiautomatic mode, we select an eclipsing binary system, based on its placement in the sky, and observe it all night long - usually many nights in a row. We choose binaries with short enough periods to assure us of obtaining a complete light curve (and hence an eclipse) every night we observe. Second, we are striving to increase the photometric precision of each observation through the use of multiple comparison stars (ensemble photometry). We are also, in conjunction with California Polytechnic State University, investigating other ways of increasing the photometric precision of these low-cost systems (see E. Sturm this conference). Finally, we are utilizing complete, as opposed to partial, light curves in our analysis. Information outside primary eclipses is gathered as a matter of course, and its use can improve precision. A total of 186 complete light curves were obtained at the Dark Ridge and Orion Observatories during the 2004 observing season on six eclipsing binaries (TZ Boo, V523 Cas, RW Com, V1191 Cyg, GM Dra, and V400 Lyr). Please see T. Smith and R. Genet (this conference) for preliminary results on V523 Cas (30+ complete light curves).

Radiotherapy with or without chemotherapy in muscle-invasive bladder cancer.

PubMed

James, Nicholas D; Hussain, Syed A; Hall, Emma; Jenkins, Peter; Tremlett, Jean; Rawlings, Christine; Crundwell, Malcolm; Sizer, Bruce; Sreenivasan, Thiagarajan; Hendron, Carey; Lewis, Rebecca; Waters, Rachel; Huddart, Robert A

2012-04-19

Radiotherapy is an alternative to cystectomy in patients with muscle-invasive bladder cancer. In other disease sites, synchronous chemoradiotherapy has been associated with increased local control and improved survival, as compared with radiotherapy alone. In this multicenter, phase 3 trial, we randomly assigned 360 patients with muscle-invasive bladder cancer to undergo radiotherapy with or without synchronous chemotherapy. The regimen consisted of fluorouracil (500 mg per square meter of body-surface area per day) during fractions 1 to 5 and 16 to 20 of radiotherapy and mitomycin C (12 mg per square meter) on day 1. Patients were also randomly assigned to undergo either whole-bladder radiotherapy or modified-volume radiotherapy (in which the volume of bladder receiving full-dose radiotherapy was reduced) in a partial 2-by-2 factorial design (results not reported here). The primary end point was survival free of locoregional disease. Secondary end points included overall survival and toxic effects. At 2 years, rates of locoregional disease-free survival were 67% (95% confidence interval [CI], 59 to 74) in the chemoradiotherapy group and 54% (95% CI, 46 to 62) in the radiotherapy group. With a median follow-up of 69.9 months, the hazard ratio in the chemoradiotherapy group was 0.68 (95% CI, 0.48 to 0.96; P=0.03). Five-year rates of overall survival were 48% (95% CI, 40 to 55) in the chemoradiotherapy group and 35% (95% CI, 28 to 43) in the radiotherapy group (hazard ratio, 0.82; 95% CI, 0.63 to 1.09; P=0.16). Grade 3 or 4 adverse events were slightly more common in the chemoradiotherapy group than in the radiotherapy group during treatment (36.0% vs. 27.5%, P=0.07) but not during follow-up (8.3% vs. 15.7%, P=0.07). Synchronous chemotherapy with fluorouracil and mitomycin C combined with radiotherapy significantly improved locoregional control of bladder cancer, as compared with radiotherapy alone, with no significant increase in adverse events. (Funded by Cancer Research U.K.; BC2001 Current Controlled Trials number, ISRCTN68324339.).

Dosimetric analysis of testicular doses in prostate intensity-modulated and volumetric-modulated arc radiation therapy at different energy levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onal, Cem, E-mail: hcemonal@hotmail.com; Arslan, Gungor; Dolek, Yemliha

2016-01-01

The aim of this study is to evaluate the incidental testicular doses during prostate radiation therapy with intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc radiotherapy (VMAT) at different energies. Dosimetric data of 15 patients with intermediate-risk prostate cancer who were treated with radiotherapy were analyzed. The prescribed dose was 78 Gy in 39 fractions. Dosimetric analysis compared testicular doses generated by 7-field intensity-modulated radiotherapy and volumetric-modulated arc radiotherapy with a single arc at 6, 10, and 15 MV energy levels. Testicular doses calculated from the treatment planning system and doses measured from the detectors were analyzed. Mean testicular doses from themore » intensity-modulated radiotherapy and volumetric-modulated arc radiotherapy per fraction calculated in the treatment planning system were 16.3 ± 10.3 cGy vs 21.5 ± 11.2 cGy (p = 0.03) at 6 MV, 13.4 ± 10.4 cGy vs 17.8 ± 10.7 cGy (p = 0.04) at 10 MV, and 10.6 ± 8.5 cGy vs 14.5 ± 8.6 cGy (p = 0.03) at 15 MV, respectively. Mean scattered testicular doses in the phantom measurements were 99.5 ± 17.2 cGy, 118.7 ± 16.4 cGy, and 193.9 ± 14.5 cGy at 6, 10, and 15 MV, respectively, in the intensity-modulated radiotherapy plans. In the volumetric-modulated arc radiotherapy plans, corresponding testicular doses per course were 90.4 ± 16.3 cGy, 103.6 ± 16.4 cGy, and 139.3 ± 14.6 cGy at 6, 10, and 15 MV, respectively. In conclusions, this study was the first to measure the incidental testicular doses by intensity-modulated radiotherapy and volumetric-modulated arc radiotherapy plans at different energy levels during prostate-only irradiation. Higher photon energy and volumetric-modulated arc radiotherapy plans resulted in higher incidental testicular doses compared with lower photon energy and intensity-modulated radiotherapy plans.« less

A longitudinal study on the radiation-induced thyroid gland changes after external beam radiotherapy of nasopharyngeal carcinoma.

PubMed

Lin, Zhixiong; Wu, Vincent Wing-Cheung; Lin, Jing; Feng, Huiting; Chen, Longhua

2011-01-01

Radiation-induced thyroid disorders have been reported in radiotherapy of head and neck cancers. This study evaluated the radiation-induced damages to thyroid gland in patients with nasopharyngeal carcinoma (NPC). Forty-five patients with NPC treated by radiotherapy underwent baseline thyroid hormones (free triiodothyronine, free thyroxine [fT4], and thyrotropin [TSH]) examination and CT scan before radiotherapy. The volume of the thyroid gland was calculated by delineating the structure in the corresponding CT slices using the radiotherapy treatment planning system. The thyroid doses were estimated using the treatment planning system. Subsequent CT scans were conducted at 6, 12, and 18 months after radiotherapy, whereas the hormone levels were assessed at 3, 6, 12, and 18 months after radiotherapy. Trend lines of the volume and hormone level changes against time were plotted. The relationship between the dose and the change of thyroid volume and hormone levels were evaluated using the Pearson correlation test. An average of 20% thyroid volume reduction in the first 6 months and a further 8% shrinkage at 12 months after radiotherapy were observed. The volume reduction was dependent on the mean thyroid doses at 6, 12, and 18 months after radiotherapy (r = -0.399, -0.472, and -0.417, respectively). Serum free triiodothyronine and fT4 levels showed mild changes of <2.5% at 6 months, started to drop by 8.8% and 11.3%, respectively, at 12 months, and became stable at 18 months. The mean serum TSH level increased mildly at 6 months after radiotherapy and more steeply after 18 months. At 18 months after radiotherapy, 12 patients had primary hypothyroidism with an elevated serum TSH, in which 4 of them also presented with low serum fT4. There was a significant difference (p = 0.014) in the mean thyroid doses between patients with hypothyroidism and normal thyroid function. Radiotherapy for patients with NPC caused radiation-induced changes of the thyroid gland. The shrinkage of the gland was greatest in the first 6 months after radiotherapy, whereas the serum fT4 and TSH levels changed at 12 months. Radiation-induced changes were dependent on the mean dose to the gland. Therefore, measures to reduce the thyroid dose in radiotherapy should be considered.

Strategies For Clinical Implementation: Precision Oncology At Three Distinct Institutions.

PubMed

Nadauld, Lincoln D; Ford, James M; Pritchard, Daryl; Brown, Thomas

2018-05-01

Despite rapid advances in molecular diagnostics and targeted therapeutics, the adoption of precision medicine into clinical oncology workflows has been slow. Questions about clinical utility, inconsistent reimbursement for molecular diagnostics, and limited access to targeted therapies are some of the major hurdles that have hampered clinical adoption. Despite these challenges, providers have invested in precision medicine programs in an ongoing search for innovative care models to deliver improved patient outcomes and achieve economic gains. We describe the precision oncology medicine programs implemented by an integrated delivery system, a community care center, and an academic medical center, to demonstrate the approaches and challenges associated with clinical implementation efforts designed to advance this treatment paradigm. Payer policies that include coverage for broad genomic testing panels would support the broader application of precision medicine, deepen research benefits, and bring targeted therapies to more patients with advanced cancer.

[Heavy charged particle radiotherapy--proton beam].

PubMed

Ogino, Takashi

2003-12-01

Proton beam therapy (PBT) makes it possible to deliver a higher concentration of radiation to the tumor by its Bragg-peak, and is easy to utilize due to its identical biological characteristics with X-rays. PBT has a half-century history, and more than 35,000 patients have been reported as having had treatments with proton beams worldwide. The historic change to this therapy occurred in the 1990s, when the Loma Linda University Medical Center began clinical activity as the first hospital in the world to utilize a medically dedicated proton therapy facility. Since then, similar hospital-based medically dedicated facilities have been constructed. Results from around the world have shown the therapeutic superiority of PBT over alternative treatment options for ocular melanoma, skull base sarcoma, head and neck cancer, lung cancer, esophageal cancer, hepatocellular carcinoma, and prostate cancer. PBT is expected to achieve further advancement both clinically and technologically.

Accuracy in breast shape alignment with 3D surface fitting algorithms.

PubMed

Riboldi, Marco; Gierga, David P; Chen, George T Y; Baroni, Guido

2009-04-01

Surface imaging is in use in radiotherapy clinical practice for patient setup optimization and monitoring. Breast alignment is accomplished by searching for a tentative spatial correspondence between the reference and daily surface shape models. In this study, the authors quantify whole breast shape alignment by relying on texture features digitized on 3D surface models. Texture feature localization was validated through repeated measurements in a silicone breast phantom, mounted on a high precision mechanical stage. Clinical investigations on breast shape alignment included 133 fractions in 18 patients treated with accelerated partial breast irradiation. The breast shape was detected with a 3D video based surface imaging system so that breathing was compensated. An in-house algorithm for breast alignment, based on surface fitting constrained by nipple matching (constrained surface fitting), was applied. Results were compared with a commercial software where no constraints are utilized (unconstrained surface fitting). Texture feature localization was validated within 2 mm in each anatomical direction. Clinical data show that unconstrained surface fitting achieves adequate accuracy in most cases, though nipple mismatch is considerably higher than residual surface distances (3.9 mm vs 0.6 mm on average). Outliers beyond 1 cm can be experienced as the result of a degenerate surface fit, where unconstrained surface fitting is not sufficient to establish spatial correspondence. In the constrained surface fitting algorithm, average surface mismatch within 1 mm was obtained when nipple position was forced to match in the [1.5; 5] mm range. In conclusion, optimal results can be obtained by trading off the desired overall surface congruence vs matching of selected landmarks (constraint). Constrained surface fitting is put forward to represent an improvement in setup accuracy for those applications where whole breast positional reproducibility is an issue.

[Task sharing with radiotherapy technicians in image-guided radiotherapy].

PubMed

Diaz, O; Lorchel, F; Revault, C; Mornex, F

2013-10-01

The development of accelerators with on-board imaging systems now allows better target volumes reset at the time of irradiation (image-guided radiotherapy [IGRT]). However, these technological advances in the control of repositioning led to a multiplication of tasks for each actor in radiotherapy and increase the time available for the treatment, whether for radiotherapy technicians or radiation oncologists. As there is currently no explicit regulatory framework governing the use of IGRT, some institutional experiments show that a transfer is possible between radiation oncologists and radiotherapy technicians for on-line verification of image positioning. Initial training for every technical and drafting procedures within institutions will improve audit quality by reducing interindividual variability. Copyright © 2013. Published by Elsevier SAS.

Prediction of radiation-induced normal tissue complications in radiotherapy using functional image data

NASA Astrophysics Data System (ADS)

Nioutsikou, Elena; Partridge, Mike; Bedford, James L.; Webb, Steve

2005-03-01

The aim of this study has been to explicitly include the functional heterogeneity of an organ as a factor that contributes to the probability of complication of normal tissues following radiotherapy. Situations for which the inclusion of this information can be advantageous to the design of treatment plans are then investigated. A Java program has been implemented for this purpose. This makes use of a voxelated model of a patient, which is based on registered anatomical and functional data in order to enable functional voxel weighting. Using this model, the functional dose-volume histogram (fDVH) and the functional normal tissue complication probability (fNTCP) are then introduced as extensions to the conventional dose-volume histogram (DVH) and normal tissue complication probability (NTCP). In the presence of functional heterogeneity, these tools are physically more meaningful for plan evaluation than the traditional indices, as they incorporate additional information and are anticipated to show a better correlation with outcome. New parameters mf, nf and TD50f are required to replace the m, n and TD50 parameters. A range of plausible values was investigated, awaiting fitting of these new parameters to patient outcomes where functional data have been measured. As an example, the model is applied to two lung datasets utilizing accurately registered computed tomography (CT) and single photon emission computed tomography (SPECT) perfusion scans. Assuming a linear perfusion-function relationship, the biological index mean perfusion weighted lung dose (MPWLD) has been extracted from integration over outlined regions of interest. In agreement with the MPWLD ranking, the fNTCP predictions reveal that incorporation of functional imaging in radiotherapy treatment planning is most beneficial for organs with a large volume effect and large focal areas of dysfunction. There is, however, no additional advantage in cases presenting with homogeneous function. Although presented for lung radiotherapy, this model is general. It can also be applied to positron emission tomography (PET)-CT or functional magnetic resonance imaging (fMRI)-CT registered data and extended to the functional description of tumour control probability.

Skeletal dosimetry models for alpha-particles for use in molecular radiotherapy

NASA Astrophysics Data System (ADS)

Watchman, Christopher J.

Molecular radiotherapy is a cancer treatment methodology whereby a radionuclide is combined with a biologically active molecule to preferentially target cancer cells. Alpha-particle emitting radionuclides show significant potential for use in molecular radiotherapy due to the short range of the alpha-particles in tissue and their high rates of energy deposition. Current radiation dosimetry models used to assess alpha emitter dose in the skeleton were developed originally for occupational applications. In medical dosimetry, individual variability in uptake, translocation and other biological factors can result in poor correlation of clinical outcome with marrow dose estimates determined using existing skeletal models. Methods presented in this work were developed in response to the need for dosimetry models which account for these biological and patient-specific factors. Dosimetry models are presented for trabecular bone alpha particle dosimetry as well as a model for cortical bone dosimetry. These radiation transport models are the 3D chord-based infinite spongiosa transport model (3D-CBIST) and the chord-based infinite cortical transport model (CBICT), respectively. Absorbed fraction data for several skeletal tissues for several subjects are presented. Each modeling strategy accounts for biological parameters, such as bone marrow cellularity, not previously incorporated into alpha-particle skeletal dosimetry models used in radiation protection. Using these data a study investigating the variability in alpha-particle absorbed fractions in the human skeleton is also presented. Data is also offered relating skeletal tissue masses in individual bone sites for a range of ages. These data are necessary for dose calculations and have previously only been available as whole body tissue masses. A revised 3D-CBIST model is also presented which allows for changes in endosteum thickness to account for revised target cell location of tissues involved in the radiological induction of bone cancer. In addition, new data are presented on the location of bone-marrow stem cells within the marrow cavities of trabecular bone of the pelvis. All results presented in this work may be applied to occupational exposures, but their greatest utility lies in dose assessments for alpha-emitters in molecular radiotherapy.

WE-FG-206-08: Pulmonary Functional Imaging Biomarkers of NSCLC to Guide and Optimize Functional Lung Avoidance Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheikh, Khadija; Capaldi, Dante PI; Parraga, Grace

Purpose: Functional lung avoidance radiotherapy promises optimized therapy planning by minimizing dose to well-functioning lung and maximizing dose to the rest of the lung. Patients with NSCLC commonly present with co-morbid COPD and heterogeneously distributed ventilation abnormalities stemming from emphysema, airways disease, and tumour burden. We hypothesized that pulmonary functional imaging methods may be used to optimize radiotherapy plans to avoid regions of well-functioning lung and significantly improve outcomes like quality-of-life and survival. To ascertain the utility of functional lung avoidance therapy in clinical practice, we measured COPD phenotypes in NSCLC patients enrolled in a randomized-controlled-clinical-trial prior to curative intentmore » therapy. Methods: Thirty stage IIIA/IIIB NSCLC patients provided written informed consent to a randomized-controlled-clinical-trial ( http://clinicaltrials.gov/ct2/show/NCT02002052 ) comparing outcomes in patients randomized to standard or image-guided radiotherapy. Hyperpolarized noble gas MRI ventilation-defect-percent (VDP) (Kirby et al, Acad Radiol, 2012) as well as CT-emphysema measurements were determined. Patients were stratified based on quantitative imaging evidence of ventilation-defects and emphysema into two subgroups: 1) tumour-specific ventilation defects only (TSD), and, 2) tumour-specific and other ventilation defects with and without emphysema (TSD{sub VE}). Receiver-operating-characteristic (ROC) curves were used to characterize the performance of clinical measures as predictors of the presence of non-tumour specific ventilation defects. Results: Twenty-one out of thirty subjects (70%) had non-tumour specific ventilation defects (TSD{sub VE}) and nine subjects had ONLY tumour-specific defects (TSD). Subjects in the TSD{sub VE} group had significantly greater smoking-history (p=.006) and airflow obstruction (FEV{sub 1}/FVC) (p=.001). ROC analysis demonstrated an 87% classification rate for smoking pack-years, 90% for FEV{sub 1}/FVC, and 56% for tumour RECIST measurements for identifying patients with non-tumour and tumour-specific ventilation abnormalities. Conclusion: 70% of NSCLC patients had ventilation abnormalities stemming from emphysema, airways disease and tumour burden. Smoking-history and airflow obstruction, but not RECIST, identified NSCLC patients with ventilation abnormalities appropriate for functional lung avoidance therapy.« less

SU-D-BRB-05: Quantum Learning for Knowledge-Based Response-Adaptive Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

El Naqa, I; Ten, R

Purpose: There is tremendous excitement in radiotherapy about applying data-driven methods to develop personalized clinical decisions for real-time response-based adaptation. However, classical statistical learning methods lack in terms of efficiency and ability to predict outcomes under conditions of uncertainty and incomplete information. Therefore, we are investigating physics-inspired machine learning approaches by utilizing quantum principles for developing a robust framework to dynamically adapt treatments to individual patient’s characteristics and optimize outcomes. Methods: We studied 88 liver SBRT patients with 35 on non-adaptive and 53 on adaptive protocols. Adaptation was based on liver function using a split-course of 3+2 fractions with amore » month break. The radiotherapy environment was modeled as a Markov decision process (MDP) of baseline and one month into treatment states. The patient environment was modeled by a 5-variable state represented by patient’s clinical and dosimetric covariates. For comparison of classical and quantum learning methods, decision-making to adapt at one month was considered. The MDP objective was defined by the complication-free tumor control (P{sup +}=TCPx(1-NTCP)). A simple regression model represented state-action mapping. Single bit in classical MDP and a qubit of 2-superimposed states in quantum MDP represented the decision actions. Classical decision selection was done using reinforcement Q-learning and quantum searching was performed using Grover’s algorithm, which applies uniform superposition over possible states and yields quadratic speed-up. Results: Classical/quantum MDPs suggested adaptation (probability amplitude ≥0.5) 79% of the time for splitcourses and 100% for continuous-courses. However, the classical MDP had an average adaptation probability of 0.5±0.22 while the quantum algorithm reached 0.76±0.28. In cases where adaptation failed, classical MDP yielded 0.31±0.26 average amplitude while the quantum approach averaged a more optimistic 0.57±0.4, but with high phase fluctuations. Conclusion: Our results demonstrate that quantum machine learning approaches provide a feasible and promising framework for real-time and sequential clinical decision-making in adaptive radiotherapy.« less

Hybrid adaptive radiotherapy with on-line MRI in cervix cancer IMRT.

PubMed

Oh, Seungjong; Stewart, James; Moseley, Joanne; Kelly, Valerie; Lim, Karen; Xie, Jason; Fyles, Anthony; Brock, Kristy K; Lundin, Anna; Rehbinder, Henrik; Milosevic, Michael; Jaffray, David; Cho, Young-Bin

2014-02-01

Substantial organ motion and tumor shrinkage occur during radiotherapy for cervix cancer. IMRT planning studies have shown that the quality of radiation delivery is influenced by these anatomical changes, therefore the adaptation of treatment plans may be warranted. Image guidance with off-line replanning, i.e. hybrid-adaptation, is recognized as one of the most practical adaptation strategies. In this study, we investigated the effects of soft tissue image guidance using on-line MR while varying the frequency of off-line replanning on the adaptation of cervix IMRT. 33 cervical cancer patients underwent planning and weekly pelvic MRI scans during radiotherapy. 5 patients of 33 were identified in a previous retrospective adaptive planning study, in which the coverage of gross tumor volume/clinical target volume (GTV/CTV) was not acceptable given single off-line IMRT replan using a 3mm PTV margin with bone matching. These 5 patients and a randomly selected 10 patients from the remaining 28 patients, a total of 15 patients of 33, were considered in this study. Two matching methods for image guidance (bone to bone and soft tissue to dose matrix) and three frequencies of off-line replanning (none, single, and weekly) were simulated and compared with respect to target coverage (cervix, GTV, lower uterus, parametrium, upper vagina, tumor related CTV and elective lymph node CTV) and OAR sparing (bladder, bowel, rectum, and sigmoid). Cost (total process time) and benefit (target coverage) were analyzed for comparison. Hybrid adaptation (image guidance with off-line replanning) significantly enhanced target coverage for both 5 difficult and 10 standard cases. Concerning image guidance, bone matching was short of delivering enough doses for 5 difficult cases even with a weekly off-line replan. Soft tissue image guidance proved successful for all cases except one when single or more frequent replans were utilized in the difficult cases. Cost and benefit analysis preferred (soft tissue) image guidance over (frequent) off-line replanning. On-line MRI based image guidance (with combination of dose distribution) is a crucial element for a successful hybrid adaptive radiotherapy. Frequent off-line replanning adjuvantly enhances adaptation quality. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, C.K.K.; Bloomfield, C.D.; Goldman, A.I.

Since Hodgkin's disease patients with large mediastinal masses frequently relapse in the intrathoracic area after regular mantle field irradiation, the feasibility and utility of low dose lung irradiation as an initial part of the supradiaphragmatic field was examined. Fifteen newly diagnosed patients with Hodgkin's disease and large mediastinal masses were treated with 1000 to 2000 rad to the lung as a part of extended field radiotherapy. All patients received radiotherapy alone. Results of treatment were compared with those in 20 similar patients who were treated only with extended field irradiation. With a minimum follow-up of 24 months, only 2 patientsmore » (13%) who received lung irradiation have recurred and only one of these recurred in the lung. In contrast 15 (79%) of the 19 complete responders who were treated without lung irradiation had relapsed by 24 months, 9 in the intrathoracic region. Recurrence-free survival was significantly longer in patients who received lung irradiation. No increased frequency in serious complications has been experienced to date with low dose whole lung irradiation, compared with regular mantle field treatment. This study suggests that lung irradiation may be a feasible alternative to adjuvant combination chemotherapy when treating patients with Hodgkin's desease and large mediastinal masses.« less

A technique for generating phase-space-based Monte Carlo beamlets in radiotherapy applications.

PubMed

Bush, K; Popescu, I A; Zavgorodni, S

2008-09-21

As radiotherapy treatment planning moves toward Monte Carlo (MC) based dose calculation methods, the MC beamlet is becoming an increasingly common optimization entity. At present, methods used to produce MC beamlets have utilized a particle source model (PSM) approach. In this work we outline the implementation of a phase-space-based approach to MC beamlet generation that is expected to provide greater accuracy in beamlet dose distributions. In this approach a standard BEAMnrc phase space is sorted and divided into beamlets with particles labeled using the inheritable particle history variable. This is achieved with the use of an efficient sorting algorithm, capable of sorting a phase space of any size into the required number of beamlets in only two passes. Sorting a phase space of five million particles can be achieved in less than 8 s on a single-core 2.2 GHz CPU. The beamlets can then be transported separately into a patient CT dataset, producing separate dose distributions (doselets). Methods for doselet normalization and conversion of dose to absolute units of Gy for use in intensity modulated radiation therapy (IMRT) plan optimization are also described.

Alterations of nutritional status: impact of chemotherapy and radiation therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donaldson, S.S.; Lenon, R.A.

1979-05-01

The nutritional status of a cancer patient may be affected by the tumor, the chemotherapy and/or radiation therapy directed against the tumor, and by complications associated with that therapy. Chemotherpay-radiotherapy is not confined exclusively to malignant cell populations; thus, normal tissues may also be affected by the therapy and may contribute to specific nutritional problems. Impaired nutrition due to anorexia, mucositis, nausea, vomiting, and diarrhea may be dependent upon the specific chemotherapeutic agent, dose, or schedule utilized. Similar side effects from radiation therapy depend upon the dose, fractionation, and volume irradiated. When combined modality treatment is given the nutritional consequencesmore » may be magnified. Prospective, randomized clinical trials are underway to investigate the efficacy of nutritional support during chemotherapy-radiotherapy on tolerance to treatment, complications from treatment, and response rates to treatment. Preliminary results demonstrate that the administration of total parenteral nutrition is successful in maintaining weight during radiation therapy and chemotherapy, but that weight loss occurs after discontinuation of nutritional support. Thus, longterm evaluation is mandatory to learn the impact of nutritional support on survival, diease-free survival, and complication rates, as well as on the possible prevention of morbidity associated with aggressive chemotherapy-radiation therapy.« less

Effects of Ionizing Radiation on DNA Methylation: From Experimental Biology to Clinical Applications

PubMed Central

Miousse, Isabelle R.; Kutanzi, Kristy R.; Koturbash, Igor

2017-01-01

Purpose Ionizing radiation (IR) is a ubiquitous environmental stressor with genotoxic and epigenotoxic capabilities. Terrestrial IR, predominantly a low-linear energy transfer (LET) radiation, is being widely utilized in medicine, as well as in multiple industrial applications. Additionally, an interest in understanding the effects of high-LET irradiation is emerging due to the potential of exposure during space missions and the growing utilization of LET radiation in medicine. Conclusions In this review, we summarize the current knowledge of the effects of IR on DNA methylation, a key epigenetic mechanism regulating the expression of genetic information. We discuss global, repetitive elements and gene-specific DNA methylation in light of exposure to high and low doses of high- or low-LET IR, fractionated IR exposure, and bystander effects. Finally, we describe the mechanisms of IR-induced alterations to DNA methylation and discuss ways in which that understanding can be applied clinically, including utilization of DNA methylation as a predictor of response to radiotherapy and in the manipulation of DNA methylation patterns for tumor radiosensitization. PMID:28134023

Effects of ionizing radiation on DNA methylation: from experimental biology to clinical applications.

PubMed

Miousse, Isabelle R; Kutanzi, Kristy R; Koturbash, Igor

2017-05-01

Ionizing radiation (IR) is a ubiquitous environmental stressor with genotoxic and epigenotoxic capabilities. Terrestrial IR, predominantly a low-linear energy transfer (LET) radiation, is being widely utilized in medicine, as well as in multiple industrial applications. Additionally, an interest in understanding the effects of high-LET irradiation is emerging due to the potential of exposure during space missions and the growing utilization of high-LET radiation in medicine. In this review, we summarize the current knowledge of the effects of IR on DNA methylation, a key epigenetic mechanism regulating the expression of genetic information. We discuss global, repetitive elements and gene-specific DNA methylation in light of exposure to high and low doses of high- or low-LET IR, fractionated IR exposure, and bystander effects. Finally, we describe the mechanisms of IR-induced alterations to DNA methylation and discuss ways in which that understanding can be applied clinically, including utilization of DNA methylation as a predictor of response to radiotherapy and in the manipulation of DNA methylation patterns for tumor radiosensitization.

Dosimetric study of different radiotherapy planning approaches for hippocampal avoidance whole-brain radiation therapy (HA-WBRT) based on fused CT and MRI imaging.

PubMed

Wang, Bu-Hai; Hua, Wei; Gu, Xiang; Wang, Xiao-Lei; Li, Jun; Liu, Li-Qin; Huang, Yu-Xiang

2015-12-01

The purpose of this study was to compare the dosimetric characteristics for hippocampal avoidance (HA) between the treatment plans based on fused CT and MRI imaging during whole brain radiotherapy (WBRT) pertaining to: (1) 3-dimensional conformal radiotherapy (3D-CRT), (2) dynamic intensity modulated radiation therapy (dIMRT), and (3) RapidArc for patients with brain metastases. In our study, HA was defined as hippocampus beyond 5 mm, and planning target volume (PTV) was obtained subtracting HA volume from the volume of whole brain. There were 10 selected patients diagnosed with brain metastases receiving WBRT. These patients received plans for 3D-CRT (two fields), dIMRT (seven non-coplanar fields) and RapidArc (dual arc). The prescribed dose 30 Gy in 10 fractions was delivered to the whole-brain clinical target volume of patients. On the premise of meeting the clinical requirements, we compared target dose distribution, target coverage (TC), homogeneity index (HI), dose of organs at risk (OARs), monitor units (MU) and treatment time between the above three radiotherapy plans. V90 %, V95 % and TC of PTV for 3D-CRT plan were lowest of the three plans. V90 %, V95 % and HI of PTV in RapidArc plan were superior to the other two plans. TC of PTV in RapidArc plan was similar with dIMRT plan (P > 0.05). 3D-CRT was the optimal plan in the three plans for hippocampal protection. The median dose (Dmedian) and the maximum doses (Dmax) of hippocampus in 3D-CRT were 4.95, 10.87 Gy, which were lowest among the three planning approaches (P < 0.05). Dmedian and Dmax of hippocampus in dIMRT were 10.68, 14.11 Gy. Dmedian and Dmax of hippocampus in RapidArc were 10.30 gGy, 13.92 Gy. These parameters of the last two plans pertain to no significant difference (P > 0.05). When WBRT (30 Gy,10F) was equivalent to single dose 2 Gy,NTDmean of hippocampus in 3D-CRT, dIMRT and RapidArc were reduced to 3.60, 8.47, 8.20 Gy2, respectively. In addition, compared with dIMRT, MU of RapidArc was reduced and the treatment time was shortened by nearly 25 %. All three radiotherapy planning approaches in our study can meet the clinical requirements of HA. Although TC in 3D-CRT was lowest, hippocampus was protected best by this plan. So many radiation fields and the design of non-coplanar fields lead to the complication of dIMRT. TC and HI in RapidArc were superior to the other two plans with the precise of meeting the clinical requirements. The difference in protection for hippocampus between dIMRT and RapidArc was statistically significant. In addition, RapidArc can remarkably reduce MU and the treatment time.

Radiotherapy of Langerhans' Cell Histiocytosis : Results and Implications of a National Patterns-of-Care Study.

PubMed

Olschewski, Thomas; Seegenschmiedt, Michael Heinrich

2006-11-01

This patterns-of-care study was performed to define the current clinical experience with radiotherapy of Langerhans' cell histiocytosis in adults in Germany and to define open questions resulting from this study. A standardized questionnaire was sent to 198 German radiotherapy institutions. Data about patient characteristics, stage of disease, practice and fractionation of radiotherapy, outcome of therapy, etc. were systematically evaluated. 123 of 198 institutions answered the complete questionnaire (62.1%). Only 23 of the 123 institutions (18.7%) reported experience with radiotherapy of Langerhans' cell histiocytosis of adults. 18 institutions with 98 patients were evaluable. The majority of patients (72 of 98) was treated on a linear accelerator. The median single dose of radiotherapy was 2 Gy, while the median total dose was 24 Gy. 81 of 89 evaluable patients (91%) reached a local control of the treated lesion(s), 69 of those had a complete remission. Eight of 89 patients (9%) developed an in-field recurrence. 87.8% of patients experienced no acute and 97% of patients no late side effects of radiotherapy. Clinical experience with radiotherapy of Langerhans' cell histiocytosis in adults in Germany is still very limited. Nevertheless, the clinical results-with high remission and local control rates-confirm the effectiveness of radiotherapy in the multidisciplinary treatment of this disease. Due to the small number of patients in this study despite higher incidence rates, the knowledge of this disease has to be multiplied in Germany. Future patients should be systematically included into a prospective radiotherapy registry.

Assessment of image quality of a radiotherapy-specific hardware solution for PET/MRI in head and neck cancer patients.

PubMed

Winter, René M; Leibfarth, Sara; Schmidt, Holger; Zwirner, Kerstin; Mönnich, David; Welz, Stefan; Schwenzer, Nina F; la Fougère, Christian; Nikolaou, Konstantin; Gatidis, Sergios; Zips, Daniel; Thorwarth, Daniela

2018-05-07

Functional PET/MRI has great potential to improve radiotherapy planning (RTP). However, data integration requires imaging with radiotherapy-specific patient positioning. Here, we investigated the feasibility and image quality of radiotherapy-customized PET/MRI in head-and-neck cancer (HNC) patients using a dedicated hardware setup. Ten HNC patients were examined with simultaneous PET/MRI before treatment, with radiotherapy and diagnostic scan setup, respectively. We tested feasibility of radiotherapy-specific patient positioning and compared the image quality between both setups by pairwise image analysis of 18 F-FDG-PET, T1/T2-weighted and diffusion-weighted MRI. For image quality assessment, similarity measures including average symmetric surface distance (ASSD) of PET and MR-based tumor contours, MR signal-to-noise ratio (SNR) and mean apparent diffusion coefficient (ADC) value were used. PET/MRI in radiotherapy position was feasible - all patients were successfully examined. ASSD (median/range) of PET and MR contours was 0.6 (0.4-1.2) and 0.9 (0.5-1.3) mm, respectively. For T2-weighted MRI, a reduced SNR of -26.2% (-39.0--11.7) was observed with radiotherapy setup. No significant difference in mean ADC was found. Simultaneous PET/MRI in HNC patients using radiotherapy positioning aids is clinically feasible. Though SNR was reduced, the image quality obtained with a radiotherapy setup meets RTP requirements and the data can thus be used for personalized RTP. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

Cancer

MedlinePlus

... most common types of cancer treatment are surgery, radiotherapy, and chemotherapy. Treatment is aimed at removing the ... vital organs, such as the liver or brain. Radiotherapy Radiotherapy uses radiation to damage cancer cells so ...

The Multidisciplinary Management of Colorectal Cancer: Present and Future Paradigms

PubMed Central

Sievers, Chelsie K.; Kratz, Jeremy D.; Zurbriggen, Luke D.; LoConte, Noelle K.; Lubner, Sam J.; Uboha, Natalya; Mulkerin, Daniel; Matkowskyj, Kristina A.; Deming, Dustin A.

2016-01-01

As treatment strategies for patients with colorectal cancer advance, there has now become an ever-increasing need for multidisciplinary teams to care for these patients. Recent investigations into the timing and duration of perioperative therapy, as well as, the rise of molecular profiling have led to more systemic chemotherapeutic options. The most efficacious use, in terms of timing and patient selection, of these therapies in the setting of modern operative and radiotherapy techniques requires the generation of care teams discussing cases at multidisciplinary conferences. This review highlights the role of multidisciplinary team conferences, advances in perioperative chemotherapy, current clinical biomarkers, and emerging therapeutic agents for molecular subtypes of metastatic colon cancer. As our understanding of relevant molecular subtypes increases and as data becomes available on treatment response, the treatment of colorectal cancer will become more precise and effective. PMID:27582648

The Multidisciplinary Management of Colorectal Cancer: Present and Future Paradigms.

PubMed

Sievers, Chelsie K; Kratz, Jeremy D; Zurbriggen, Luke D; LoConte, Noelle K; Lubner, Sam J; Uboha, Natalya; Mulkerin, Daniel; Matkowskyj, Kristina A; Deming, Dustin A

2016-09-01

As treatment strategies for patients with colorectal cancer advance, there has now become an ever-increasing need for multidisciplinary teams to care for these patients. Recent investigations into the timing and duration of perioperative therapy, as well as, the rise of molecular profiling have led to more systemic chemotherapeutic options. The most efficacious use, in terms of timing and patient selection, of these therapies in the setting of modern operative and radiotherapy techniques requires the generation of care teams discussing cases at multidisciplinary conferences. This review highlights the role of multidisciplinary team conferences, advances in perioperative chemotherapy, current clinical biomarkers, and emerging therapeutic agents for molecular subtypes of metastatic colon cancer. As our understanding of relevant molecular subtypes increases and as data becomes available on treatment response, the treatment of colorectal cancer will become more precise and effective.

Positron emission tomography imaging approaches for external beam radiation therapies: current status and future developments

PubMed Central

Price, P M; Green, M M

2011-01-01

In an era in which it is possible to deliver radiation with high precision, there is a heightened need for enhanced imaging capabilities to improve tumour localisation for diagnostic, planning and delivery purposes. This is necessary to increase the accuracy and overall efficacy of all types of external beam radiotherapy (RT), including particle therapies. Positron emission tomography (PET) has the potential to fulfil this need by imaging fundamental aspects of tumour biology. The key areas in which PET may support the RT process include improving disease diagnosis and staging; assisting tumour volume delineation; defining tumour phenotype or biological tumour volume; assessment of treatment response; and in-beam monitoring of radiation dosimetry. The role of PET and its current developmental status in these key areas are overviewed in this review, highlighting the advantages and drawbacks. PMID:21427180

Current approach to fertility preservation by embryo cryopreservation

PubMed Central

Bedoschi, Giuliano; Oktay, Kutluk

2013-01-01

The ovaries are susceptible to damage following treatment with gonadotoxic chemotherapy, pelvic radiotherapy, and/or ovarian surgery. Gonadotoxic treatments have also been used in patients with various nonmalignant systemic diseases. Any women of reproductive age with a sufficiently high risk of developing future ovarian failure due to those medical interventions may benefit from embryo cryopreservation though the tools of assessment of such a risk are still not very precise. Furthermore, the risk assessment can be influenced by many other factors such as the delay expected after chemotherapy and the number of children desired in the future. Embryo cryopreservation is an established and most successful method of fertility preservation when there is sufficient time available to perform ovarian stimulation. This publication will review the current state, approach, and indications of embryo cryopreservation for fertility preservation. PMID:23535505

Membrane Signaling Induced by High Doses of Ionizing Radiation in the Endothelial Compartment. Relevance in Radiation Toxicity

PubMed Central

Corre, Isabelle; Guillonneau, Maëva; Paris, François

2013-01-01

Tumor areas can now be very precisely delimited thanks to technical progress in imaging and ballistics. This has also led to the development of novel radiotherapy protocols, delivering higher doses of ionizing radiation directly to cancer cells. Despite this, radiation toxicity in healthy tissue remains a major issue, particularly with dose-escalation in these new protocols. Acute and late tissue damage following irradiation have both been linked to the endothelium irrigating normal tissues. The molecular mechanisms involved in the endothelial response to high doses of radiation are associated with signaling from the plasma membrane, mainly via the acid sphingomyelinase/ceramide pathway. This review describes this signaling pathway and discusses the relevance of targeting endothelial signaling to protect healthy tissues from the deleterious effects of high doses of radiation. PMID:24252908

Development and evaluation of multi-energy PbO dosimeter for quality assurance of image-guide radiation therapy devices

NASA Astrophysics Data System (ADS)

Kim, Kyo-Tae; Heo, Ye-Ji; Han, Moo-Jae; Oh, Kyung-Min; Lee, Young-Kyu; Kim, Shin-Wook; Park, Sung-Kwang

2017-04-01

In radiation therapy, accurate radiotherapy treatment plan (RTP) reproduction is necessary to optimize the clinical results. Thus, attempts have recently been made to ensure high RTP reproducibility using image-guide radiation therapy (IGRT) technology. However, the clinical use of digital X-ray equipment requires extended quality assurance (QA) for those devices, since the IGRT device quality determines the precision of intensity-modulated radiation therapy. The study described in this paper was focused on developing a multi-energy PbO dosimeter for IGRT device QA. The Schottky-type polycrystalline PbO dosimeter with a Au/PbO/ITO structure was evaluated by comparing its response coincidence, dose linearity, measurement reproducibility, linear attenuation coefficient, and percent depth dose with those of Si diode and standard ionization chamber dosimeters.

Precision medicine in pediatric oncology: Lessons learned and next steps.

PubMed

Mody, Rajen J; Prensner, John R; Everett, Jessica; Parsons, D Williams; Chinnaiyan, Arul M

2017-03-01

The maturation of genomic technologies has enabled new discoveries in disease pathogenesis as well as new approaches to patient care. In pediatric oncology, patients may now receive individualized genomic analysis to identify molecular aberrations of relevance for diagnosis and/or treatment. In this context, several recent clinical studies have begun to explore the feasibility and utility of genomics-driven precision medicine. Here, we review the major developments in this field, discuss current limitations, and explore aspects of the clinical implementation of precision medicine, which lack consensus. Lastly, we discuss ongoing scientific efforts in this arena, which may yield future clinical applications. © 2016 Wiley Periodicals, Inc.

Precision medicine in pediatric oncology: Lessons learned and next steps

PubMed Central

Mody, Rajen J.; Prensner, John R.; Everett, Jessica; Parsons, D. Williams; Chinnaiyan, Arul M.

2017-01-01

The maturation of genomic technologies has enabled new discoveries in disease pathogenesis as well as new approaches to patient care. In pediatric oncology, patients may now receive individualized genomic analysis to identify molecular aberrations of relevance for diagnosis and/or treatment. In this context, several recent clinical studies have begun to explore the feasibility and utility of genomics-driven precision medicine. Here, we review the major developments in this field, discuss current limitations, and explore aspects of the clinical implementation of precision medicine, which lack consensus. Lastly, we discuss ongoing scientific efforts in this arena, which may yield future clinical applications. PMID:27748023

[Why proton therapy? And how?

PubMed

Thariat, Juliette; Habrand, Jean Louis; Lesueur, Paul; Chaikh, Abdulhamid; Kammerer, Emmanuel; Lecomte, Delphine; Batalla, Alain; Balosso, Jacques; Tessonnier, Thomas

2018-03-01

Proton therapy is a radiotherapy, based on the use of protons, charged subatomic particles that stop at a given depth depending on their initial energy (pristine Bragg peak), avoiding any output beam, unlike the photons used in most of the other modalities of radiotherapy. Proton therapy has been used for 60 years, but has only become ubiquitous in the last decade because of recent major advances in particle accelerator technology. This article reviews the history of clinical implementation of protons, the nature of the technological advances that now allows its expansion at a lower cost. It also addresses the technical and physical specificities of proton therapy and the clinical situations for which proton therapy may be relevant but requires evidence. Different proton therapy techniques are possible. These are explained in terms of their clinical potential by explaining the current terminology (such as cyclotrons, synchrotrons or synchrocyclotrons, using superconducting magnets, fixed line or arm rotary with passive diffusion delivery or active by scanning) in basic words. The requirements associated with proton therapy are increased due to the precision of the depth dose deposit. The learning curve of proton therapy requires that clinical indications be prioritized according to their associated uncertainties (such as range uncertainties and movement in lung tumors). Many clinical indications potentially fall under proton therapy ultimately. Clinical strategies are explained in a paralleled manuscript. Copyright © 2018 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.

[Hypofractionation and radiotherapy: "the eternal return"].

PubMed

Cosset, J-M; Mornex, F; Eschwège, F

2013-10-01

Hypofractionation is not a new idea in radiotherapy. The use of a few high-dose fractions has been proposed by some pioneers of our specialty in the early years of the 20th century. Hypofractionation then reappeared several times in the next decades, based on successive radiobiological concepts, a number of them having been shown to be wrong. The nominal single dose (NSD), for example, so fashionable in the 1970's, dramatically underestimated the late toxicity of the high-dose fractions. Consequently, the NSD was directly responsible for a significant increase of the incidence and of the severity of late complications in large cohorts of patients. The linear-quadratic model (LQ) unequivocally improved our understanding of fractionation sensitivity, but one has to keep in mind its limitations, both in the areas of low and high doses per fraction. For more than a decade, prostate cancer has been the subject of fierce discussions about its sensitivity to fractionation. A number of studies have suggested an unusually low (for a malignant tumor) alpha/beta ratio. However, the available data do not allow a precise evaluation of this ratio; "very low" (1.5 Gy), with an advantage of hypofractionation in terms of local control? Or simply "low" (3-4 Gy), only allowing a reduction of the total number of fractions (with a dose adequately reduced)? While waiting for complementary data, it is advised to remain very careful when modifying the classical schemes towards hypofractionation. Copyright © 2013. Published by Elsevier SAS.

Present Status of Radiotherapy in Clinical Practice

NASA Astrophysics Data System (ADS)

Duehmke, Eckhart

Aims of radiation oncology are cure from malignant diseases and - at the same time preservation of anatomy (e.g. female breast, uterus, prostate) and organ functions (e.g. brain, eye, voice, sphincter ani). At present, methods and results of clinical radiotherapy (RT) are based on experiences with natural history and radiobiology of malignant tumors in properly defined situations as well as on technical developments since World War II in geometrical and biological treatment planning in teletherapy and brachytherapy. Radiobiological research revealed tolerance limits of healthy tissues to be respected, effective total treatment doses of high cure probability depending on histology and tumor volume, and - more recently - altered fractionation schemes to be adapted to specific growth fractions and intrinsic radiosensitivities of clonogenic tumor cells. In addition, Biological Response Modifiers (BRM), such as cis-platinum, oxygen and hyperthermia may steepen cell survival curves of hypoxic tumor cells, others - such as tetrachiordekaoxid (TCDO) - may enhance repair of normal tissues. Computer assisted techniques in geometrical RT-planning based on individual healthy and pathologic anatomy (CT, MRT) provide high precision RT for well defined brain lesions by using dedicated linear accelerators (Stereotaxy). CT-based individual tissue compensators help with homogenization of distorted dose distributions in magna field irradiation for malignant lymphomas and with total body irradiation (TBI) before allogeneic bone marrow transplantation, e.g. for leukemia. RT with fast neutrons, Boron Neutron Capture Therapy (BNCT), RT with protons and heavy ions need to be tested in randomized trials before implementation into clinical routine.

Intratumoral hemorrhage because of primary spinal mixed germ cell tumor presenting with atypical radiological features in an adult.

PubMed

Yamamoto, Junkoh; Takahashi, Mayu; Nakano, Yoshiteru; Saito, Takeshi; Kitagawa, Takehiro; Ueta, Kunihiro; Miyaoka, Ryo; Nakamura, Eiichiro; Nishizawa, Shigeru

2013-10-01

Germ cell tumors are known to arise in the central nervous system, usually in the intracranial regions. However, primary spinal mixed germ cell tumors are extremely rare. This is the first reported case of intratumoral hemorrhage because of a primary spinal mixed germ cell tumor consisting of germinoma and immature teratoma in the conus medullaris of an adult patient that presented with rapid changes on magnetic resonance image (MRI). We report this rare case and discuss the clinical manifestations of an intramedullary spinal mixed germ cell tumor in adult. A case report. A 42-year-old woman experienced buttock numbness, and a spinal cord tumor was observed on the conus medullaris on MRI. The patient was scheduled for an operation in 1 month, but she developed sudden-onset neurologic deterioration. Rapid progression of the tumor was observed on follow-up MRI. The tumor was removed by emergency surgery and was identified as a primary mixed germinoma and immature teratoma. The patient received adjuvant chemotherapy and radiotherapy after gross total resection. The neurologic deficit of the patient was relieved, and recurrence of the tumor was not observed 26 months after the surgery. We present this rare case and emphasize the necessity of precise diagnosis and early treatment of primary spinal germ cell tumor. Close observation on MRI is required after surgery, and adjuvant chemotherapy and radiotherapy should be considered according to the pathologic features. Copyright © 2013 Elsevier Inc. All rights reserved.

Dose- and time-dependent gene expression alterations in prostate and colon cancer cells after in vitro exposure to carbon ion and X-irradiation

PubMed Central

Suetens, Annelies; Moreels, Marjan; Quintens, Roel; Soors, Els; Buset, Jasmine; Chiriotti, Sabina; Tabury, Kevin; Gregoire, Vincent; Baatout, Sarah

2015-01-01

Hadrontherapy is an advanced form of radiotherapy that uses beams of charged particles (such as protons and carbon ions). Compared with conventional radiotherapy, the main advantages of carbon ion therapy are the precise absorbed dose localization, along with an increased relative biological effectiveness (RBE). This high ballistic accuracy of particle beams deposits the maximal dose to the tumor, while damage to the surrounding healthy tissue is limited. Currently, hadrontherapy is being used for the treatment of specific types of cancer. Previous in vitro studies have shown that, under certain circumstances, exposure to charged particles may inhibit cell motility and migration. In the present study, we investigated the expression of four motility-related genes in prostate (PC3) and colon (Caco-2) cancer cell lines after exposure to different radiation types. Cells were irradiated with various absorbed doses (0, 0.5 and 2 Gy) of accelerated 13C-ions at the GANIL facility (Caen, France) or with X-rays. Clonogenic assays were performed to determine the RBE. RT-qPCR analysis showed dose- and time-dependent changes in the expression of CCDC88A, FN1, MYH9 and ROCK1 in both cell lines. However, whereas in PC3 cells the response to carbon ion irradiation was enhanced compared with X-irradiation, the effect was the opposite in Caco-2 cells, indicating cell-type–specific responses to the different radiation types. PMID:25190155

Assessment of national dosimetry quality audits results for teletherapy machines from 1989 to 2015.

PubMed

Muhammad, Wazir; Ullah, Asad; Mahmood, Khalid; Matiullah

2016-01-01

The purpose of this study was to ensure accuracy in radiation dose delivery, external dosimetry quality audit has an equal importance with routine dosimetry performed at clinics. To do so, dosimetry quality audit was organized by the Secondary Standard Dosimetry Laboratory (SSDL) of Pakistan Institute of Nuclear Science and Technology (PINSTECH) at the national level to investigate and minimize uncertainties involved in the measurement of absorbed dose, and to improve the accuracy of dose measurement at different radiotherapy hospitals. A total of 181 dosimetry quality audits (i.e., 102 of Co-60 and 79 of linear accelerators) for teletherapy units installed at 22 different sites were performed from 1989 to 2015. The percent deviation between users’ calculated/stated dose and evaluated dose (in the result of on-site dosimetry visits) were calculated and the results were analyzed with respect to the limits of ± 2.5% (ICRU "optimal model") ± 3.0% (IAEA on-site dosimetry visits limit) and ± 5.0% (ICRU minimal or "lowest acceptable" model). The results showed that out of 181 total on-site dosimetry visits, 20.44%, 16.02%, and 4.42% were out of acceptable limits of ± 2.5% ± 3.0%, and ± 5.0%, respectively. The importance of a proper ongoing quality assurance program, recommendations of the followed protocols, and properly calibrated thermometers, pressure gauges, and humidity meters at radiotherapy hospitals are essential in maintaining consistency and uniformity of absorbed dose measurements for precision in dose delivery.

A Kindler syndrome-associated squamous cell carcinoma treated with radiotherapy.

PubMed

Caldeira, Ademar; Trinca, William Correia; Flores, Thais Pires; Costa, Andrea Barleze; Brito, Claudio de Sá; Weigert, Karen Loureiro; Matos, Maryana Schwartzhaupt; Nicolini, Carmela; Obst, Fernando Mariano

2016-01-01

Kindler syndrome1, 2 is a genetic disorder mainly characterized by increased skin fragility and photosensitivity,3, 4 making the use of treatments based on radiation difficult or even prohibited. Thus, cases reporting Kindler syndrome patients treated with radiotherapy are rare. In this study, we report clinical outcomes and care provided for a rare case of a Kindler syndrome patient submitted to radiotherapy. Diagnosed with squamous cell carcinoma involving the buccal mucosa, the patient was exclusively treated with radiotherapy, with 70 Gy delivered on the PTV with the Volumetric Modulated Arc technique. The patient's reaction regarding control of the lesion is relevant compared to patients not affected by the syndrome. We noticed acute reactions of the skin and buccal mucosa after few radiotherapy sessions, followed by a fast reduction in the tumor volume. The efficacy of radiotherapy along with multidisciplinary actions allowed treatment continuity, leading to a complete control of the lesion and life quality improvement and showed that the use of radiotherapy on Kindler syndrome patients is possible.

Radiotherapy for breast cancer: The predictable consequences of an unmet need.

PubMed

Rodin, Danielle; Knaul, Felicia M; Lui, Tracey Y; Gospodarowicz, Mary

2016-10-01

Radiotherapy has had a transformative impact on the treatment of breast cancer, but is unavailable to the majority of breast cancer patients in low- and middle-income countries. In these settings, where many women present with advanced disease at an age when they are often the primary caregiver for their families, the lack of access to radiotherapy is particularly devastating. Until recently, this disparity has been largely neglected in the medical literature and it had been difficult to convince governments, industry, and policymakers of the importance of investing in radiotherapy, as well as broader cancer control strategies, in low-resource settings. The Lancet Radiotherapy Commission report published in 2015 challenged many assumptions about the affordability of radiotherapy treatment. Data from the Commission is presented here to support radiotherapy investment for breast cancer and discuss how the morbidity and premature mortality among adult women caused by breast cancer has a huge detrimental effect on both the health sector and the economy. Copyright © 2016. Published by Elsevier Ltd.

SU-F-R-01: Preclinical Radioimmunogenomics Study to Design Personalized Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdollahi, H

2016-06-15

Purpose: Radiogenomics is an active area of research to find clinical correlation between genomics and radiotherapy outcomes. In this era, many different biological issues should be taken into account. In this study we aimed to introduce “Radioimmunogenomics” as a new approach to study immunogetics issue regard to radiotherapy induced clinical manifestations. Methods: We studied different immunological pathways and signaling molecules which underling radiation response of normal and malignant tissues. In the other hand, we found many genes and proteins are responsible to radiation effects on biological tissues. We defined a theoretical framework to correlate these genes with radiotherapy outcomes asmore » TCP and NTCP biological dose tools. Results: Our theoretical results showed, high-throughput immunogenomics biomarkers can be correlated with radiotherapy outcomes. Genes regarding to inflammation, apoptosis, repair molecules and many other immunological markers can be defined as radioimmune markers to predict radiotherapy response. Conclusion: Radioimmunogenomics can be used as a new personalized radiotherapy research area to enhance treatment outcome as well as quality of life.« less

Feasibility of using glass-bead thermoluminescent dosimeters for radiotherapy treatment plan verification.

PubMed

Jafari, Shakardokht M; Jordan, Tom J; Distefano, Gail; Bradley, David A; Spyrou, Nicholas M; Nisbet, Andrew; Clark, Catharine H

2015-01-01

To investigate the feasibility of using glass beads as novel thermoluminescent dosemeters (TLDs) for radiotherapy treatment plan verification. Commercially available glass beads with a size of 1-mm thickness and 2-mm diameter were characterized as TLDs. Five clinical treatment plans including a conventional larynx, a conformal prostate, an intensity-modulated radiotherapy (IMRT) prostate and two stereotactic body radiation therapy (SBRT) lung plans were transferred onto a CT scan of a water-equivalent phantom (Solid Water(®), Gammex, Middleton, WI) and the dose distribution recalculated. The number of monitor units was maintained from the clinical plan and delivered accordingly. The doses determined by the glass beads were compared with those measured by a graphite-walled ionization chamber, and the respective expected doses were determined by the treatment-planning system (TPS) calculation. The mean percentage difference between measured dose with the glass beads and TPS was found to be 0.3%, -0.1%, 0.4%, 1.8% and 1.7% for the conventional larynx, conformal prostate, IMRT prostate and each of the SBRT delivery techniques, respectively. The percentage difference between measured dose with the ionization chamber and glass bead was found to be -1.2%, -1.4%, -0.1%, -0.9% and 2.4% for the above-mentioned plans, respectively. The results of measured doses with the glass beads and ionization chamber in comparison with expected doses from the TPS were analysed using a two-sided paired t-test, and there was no significant difference at p < 0.05. It is feasible to use glass-bead TLDs as dosemeters in a range of clinical plan verifications. Commercial glass beads are utilized as low-cost novel TLDs for treatment-plan verification.

Improved human observer performance in digital reconstructed radiograph verification in head and neck cancer radiotherapy.

PubMed

Sturgeon, Jared D; Cox, John A; Mayo, Lauren L; Gunn, G Brandon; Zhang, Lifei; Balter, Peter A; Dong, Lei; Awan, Musaddiq; Kocak-Uzel, Esengul; Mohamed, Abdallah Sherif Radwan; Rosenthal, David I; Fuller, Clifton David

2015-10-01

Digitally reconstructed radiographs (DRRs) are routinely used as an a priori reference for setup correction in radiotherapy. The spatial resolution of DRRs may be improved to reduce setup error in fractionated radiotherapy treatment protocols. The influence of finer CT slice thickness reconstruction (STR) and resultant increased resolution DRRs on physician setup accuracy was prospectively evaluated. Four head and neck patient CT-simulation images were acquired and used to create DRR cohorts by varying STRs at 0.5, 1, 2, 2.5, and 3 mm. DRRs were displaced relative to a fixed isocenter using 0-5 mm random shifts in the three cardinal axes. Physician observers reviewed DRRs of varying STRs and displacements and then aligned reference and test DRRs replicating daily KV imaging workflow. A total of 1,064 images were reviewed by four blinded physicians. Observer errors were analyzed using nonparametric statistics (Friedman's test) to determine whether STR cohorts had detectably different displacement profiles. Post hoc bootstrap resampling was applied to evaluate potential generalizability. The observer-based trial revealed a statistically significant difference between cohort means for observer displacement vector error ([Formula: see text]) and for [Formula: see text]-axis [Formula: see text]. Bootstrap analysis suggests a 15% gain in isocenter translational setup error with reduction of STR from 3 mm to [Formula: see text]2 mm, though interobserver variance was a larger feature than STR-associated measurement variance. Higher resolution DRRs generated using finer CT scan STR resulted in improved observer performance at shift detection and could decrease operator-dependent geometric error. Ideally, CT STRs [Formula: see text]2 mm should be utilized for DRR generation in the head and neck.

Sci-Fri PM: Radiation Therapy, Planning, Imaging, and Special Techniques - 03: The Potential Benefit Of Esophageal Sparing During Palliative Radiotherapy For Lung Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Granton, Patrick V.; Palma, David A.; Louie, Alexa

Puropose: Palliative radiotherapy is an effective technique to alleviate systems of disease burden in late-stage lung cancer patients. Previous randomized controlled studies demonstrated a survival benefit in patients with good performance status at radiation doses of 35Gy10 or greater but with an increased incidence of esophagitis. The objective of this planning study was to assess the potential impact of esophageal-sparing IMRT (ES-IMRT) compared to the current standard of care using parallel-opposed pair beams (POP). Methods: In this study, 15 patients with lung cancer treated to a dose of 30Gy in 10 fractions between August 2015 and January 2016 were identified.more » Radiation treatment plans were optimized using ES-IMRT by limiting the max esophagus point dose to 24Gy. Using published Lyman-Kutcher-Burman normal tissue complication probabilities (LKB-NTCP) models, both plans were evaluated for the likelihood of esophagitis (≥ grade 2) and pneumonitis (≥ grade 2). Results: Using ES-IMRT, the median esophageal and lung mean doses reduced from 16 and 8Gy to 7 and 7Gy, respectively. Using the LKB models, the theoretical probability of symptomatic esophagitis and pneumonitis reduced from 13 to 1%, and from 5 to 3%, respectively. The median NTD mean for the GTV and PTV of the clinically approved POP plans compared to the ES-IMRT plans were similar. Conclusions: Advanced radiotherapy techniques such as ES-IMRT may have clinical utility in reducing treatment-related toxicity in advanced lung cancer patients. Our data suggests that the rate of esophagitis can be reduced without compromising tumour control.« less

Limiting the risk of cardiac toxicity with esophageal-sparing intensity modulated radiotherapy for locally advanced lung cancers.

PubMed

Woodford, Katrina; Panettieri, Vanessa; Ruben, Jeremy D; Senthi, Sashendra

2016-05-01

Intensity modulated radiotherapy (IMRT) is routinely utilized in the treatment of locally advanced non-small cell lung cancer (NSCLC). RTOG 0617 found that overall survival was impacted by increased low (5 Gy) and intermediate (30 Gy) cardiac doses. We evaluated the impact of esophageal-sparing IMRT on cardiac doses with and without the heart considered in the planning process and predicted toxicity compared to 3D-conventional radiotherapy (3DCRT). Ten consecutive patients with N2 Stage III NSCLC treated to 60 Gy in 30 fractions, between February 2012 and September 2014, were evaluated. For each patient, 3DCRT and esophageal-sparing IMRT plans were generated. IMRT plans were then created with and without the heart considered in the optimization process. To compare plans, the dose delivered to 95% and 99% of the target (D95% and D99%), and doses to the esophagus, lung and heart were compared by determining the volume receiving X dose (VXGy) and the normal tissue complication probability (NTCP) calculated. IMRT reduced maximum esophagus dose to below 60 Gy in all patients and produced significant reductions to V50Gy, V40Gy and esophageal NTCP. The cost of this reduction was a non-statistically, non-clinically significant increase in low dose (5 Gy) lung exposure that did not worsen lung NTCP. IMRT plans produced significant cardiac sparing, with the amount of improvement correlating to the amount of heart overlapping with the target. When included in plan optimization, for selected patients further sparing of the heart and improvement in heart NTCP was possible. Esophageal-sparing IMRT can significantly spare the heart even if it is not considered in the optimization process. Further sparing can be achieved if plan optimization constrains low and intermediate heart doses, without compromising lung doses.

Analysis of Intensity-Modulated Radiation Therapy (IMRT), Proton and 3D Conformal Radiotherapy (3D-CRT) for Reducing Perioperative Cardiopulmonary Complications in Esophageal Cancer Patients.

PubMed

Ling, Ted C; Slater, Jerry M; Nookala, Prashanth; Mifflin, Rachel; Grove, Roger; Ly, Anh M; Patyal, Baldev; Slater, Jerry D; Yang, Gary Y

2014-12-05

Background. While neoadjuvant concurrent chemoradiotherapy has improved outcomes for esophageal cancer patients, surgical complication rates remain high. The most frequent perioperative complications after trimodality therapy were cardiopulmonary in nature. The radiation modality utilized can be a strong mitigating factor of perioperative complications given the location of the esophagus and its proximity to the heart and lungs. The purpose of this study is to make a dosimetric comparison of Intensity-Modulated Radiation Therapy (IMRT), proton and 3D conformal radiotherapy (3D-CRT) with regard to reducing perioperative cardiopulmonary complications in esophageal cancer patients. Materials. Ten patients with esophageal cancer treated between 2010 and 2013 were evaluated in this study. All patients were simulated with contrast-enhanced CT imaging. Separate treatment plans using proton radiotherapy, IMRT, and 3D-CRT modalities were created for each patient. Dose-volume histograms were calculated and analyzed to compare plans between the three modalities. The organs at risk (OAR) being evaluated in this study are the heart, lungs, and spinal cord. To determine statistical significance, ANOVA and two-tailed paired t-tests were performed for all data parameters. Results. The proton plans showed decreased dose to various volumes of the heart and lungs in comparison to both the IMRT and 3D-CRT plans. There was no difference between the IMRT and 3D-CRT plans in dose delivered to the lung or heart. This finding was seen consistently across the parameters analyzed in this study. Conclusions. In patients receiving radiation therapy for esophageal cancer, proton plans are technically feasible while achieving adequate coverage with lower doses delivered to the lungs and cardiac structures. This may result in decreased cardiopulmonary toxicity and less morbidity to esophageal cancer patients.

Managed care and the diffusion of intensity-modulated radiotherapy for prostate cancer.

PubMed

Jacobs, Bruce L; Zhang, Yun; Skolarus, Ted A; Wei, John T; Montie, James E; Schroeck, Florian R; Hollenbeck, Brent K

2012-12-01

To better understand associations between managed care penetration in health care markets and the adoption of intensity-modulated radiotherapy (IMRT). We used Surveillance, Epidemiology, and End Results-Medicare data to identify men diagnosed with prostate cancer between 2001 and 2007 who were treated with radiotherapy (n = 55,162). We categorized managed care penetration in Health Service Areas (HSAs) as low (<3%), intermediate (3%-10%), and high (>10%), and assessed our main outcomes (ie, probability of IMRT adoption, which is the ability of a health care market to deliver IMRT, and IMRT utilization in HSA markets) using a Cox proportional hazards model and Poisson regression model, respectively. Compared with markets with low managed care penetration, populations in highly penetrated HSAs were more racially diverse (25% vs 15% non-white, P <.01), densely populated (2110 vs 145 people/square mile, P <.01), and wealthier (median income, $48,500 vs $31,900, P <.01). The probability of IMRT adoption was greatest in markets with the highest managed care penetration (eg, 0.82 [high] vs 0.72 [low] in 2007, P = .05). Among adopting markets, the use of IMRT increased in all HSA categories. However, relative to markets with low managed care penetration, IMRT use was constrained in markets with the highest penetration (0.69 [high] vs 0.76 [low] in 2007, P <.01). Markets with higher managed care penetration demonstrated a greater propensity for acquiring IMRT technology. However, after adopting IMRT, more highly penetrated markets had roughly 7% slower growth in IMRT use during the study period. These findings provide insight into the implications of delivery system reforms for cancer-related technologies. Copyright © 2012 Elsevier Inc. All rights reserved.

Spot-scanning beam delivery with laterally- and longitudinally-mixed spot size pencil beams in heavy ion radiotherapy

NASA Astrophysics Data System (ADS)

Yan, Yuan-Lin; Liu, Xin-Guo; Dai, Zhong-Ying; Ma, Yuan-Yuan; He, Peng-Bo; Shen, Guo-Sheng; Ji, Teng-Fei; Zhang, Hui; Li, Qiang

2017-09-01

The three-dimensional (3D) spot-scanning method is one of the most commonly used irradiation methods in charged particle beam radiotherapy. Generally, spot-scanning beam delivery utilizes the same size pencil beam to irradiate the tumor targets. Here we propose a spot-scanning beam delivery method with laterally- and longitudinally-mixed size pencil beams for heavy ion radiotherapy. This uses pencil beams with a bigger spot size in the lateral direction and wider mini spread-out Bragg peak (mini-SOBP) to irradiate the inner part of a target volume, and pencil beams with a smaller spot size in the lateral direction and narrower mini-SOBP to irradiate the peripheral part of the target volume. Instead of being controlled by the accelerator, the lateral size of the pencil beam was adjusted by inserting Ta scatterers in the beam delivery line. The longitudinal size of the pencil beam (i.e. the width of the mini-SOBP) was adjusted by tilting mini ridge filters along the beam direction. The new spot-scanning beam delivery using carbon ions was investigated theoretically and compared with traditional spot-scanning beam delivery. Our results show that the new spot-scanning beam delivery has smaller lateral penumbra, steeper distal dose fall-off and the dose homogeneity (1-standard deviation/mean) in the target volume is better than 95%. Supported by Key Project of National Natural Science Foundation of China (U1232207), National Key Technology Support Program of the Ministry of Science and Technology of China (2015BAI01B11), National Key Research and Development Program of the Ministry of Science and Technology of China (2016YFC0904602) and National Natural Science Foundation of China (11075191, 11205217, 11475231, 11505249)

WE-EF-BRD-03: I Want It Now!: Advances in MRI Acquisition, Reconstruction and the Use of Priors to Enable Fast Anatomic and Physiologic Imaging to Inform Guidance and Adaptation Decisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Y.

MRI-guided treatment is a growing area of medicine, particularly in radiotherapy and surgery. The exquisite soft tissue anatomic contrast offered by MRI, along with functional imaging, makes the use of MRI during therapeutic procedures very attractive. Challenging the utility of MRI in the therapy room are many issues including the physics of MRI and the impact on the environment and therapeutic instruments, the impact of the room and instruments on the MRI; safety, space, design and cost. In this session, the applications and challenges of MRI-guided treatment will be described. The session format is: Past, present and future: MRI-guided radiotherapymore » from 2005 to 2025: Jan Lagendijk Battling Maxwell’s equations: Physics challenges and solutions for hybrid MRI systems: Paul Keall I want it now!: Advances in MRI acquisition, reconstruction and the use of priors to enable fast anatomic and physiologic imaging to inform guidance and adaptation decisions: Yanle Hu MR in the OR: The growth and applications of MRI for interventional radiology and surgery: Rebecca Fahrig Learning Objectives: To understand the history and trajectory of MRI-guided radiotherapy To understand the challenges of integrating MR imaging systems with linear accelerators To understand the latest in fast MRI methods to enable the visualisation of anatomy and physiology on radiotherapy treatment timescales To understand the growing role and challenges of MRI for image-guided surgical procedures My disclosures are publicly available and updated at: http://sydney.edu.au/medicine/radiation-physics/about-us/disclosures.php.« less

Analysis of Intensity-Modulated Radiation Therapy (IMRT), Proton and 3D Conformal Radiotherapy (3D-CRT) for Reducing Perioperative Cardiopulmonary Complications in Esophageal Cancer Patients

PubMed Central

Ling, Ted C.; Slater, Jerry M.; Nookala, Prashanth; Mifflin, Rachel; Grove, Roger; Ly, Anh M.; Patyal, Baldev; Slater, Jerry D.; Yang, Gary Y.

2014-01-01

Background. While neoadjuvant concurrent chemoradiotherapy has improved outcomes for esophageal cancer patients, surgical complication rates remain high. The most frequent perioperative complications after trimodality therapy were cardiopulmonary in nature. The radiation modality utilized can be a strong mitigating factor of perioperative complications given the location of the esophagus and its proximity to the heart and lungs. The purpose of this study is to make a dosimetric comparison of Intensity-Modulated Radiation Therapy (IMRT), proton and 3D conformal radiotherapy (3D-CRT) with regard to reducing perioperative cardiopulmonary complications in esophageal cancer patients. Materials. Ten patients with esophageal cancer treated between 2010 and 2013 were evaluated in this study. All patients were simulated with contrast-enhanced CT imaging. Separate treatment plans using proton radiotherapy, IMRT, and 3D-CRT modalities were created for each patient. Dose-volume histograms were calculated and analyzed to compare plans between the three modalities. The organs at risk (OAR) being evaluated in this study are the heart, lungs, and spinal cord. To determine statistical significance, ANOVA and two-tailed paired t-tests were performed for all data parameters. Results. The proton plans showed decreased dose to various volumes of the heart and lungs in comparison to both the IMRT and 3D-CRT plans. There was no difference between the IMRT and 3D-CRT plans in dose delivered to the lung or heart. This finding was seen consistently across the parameters analyzed in this study. Conclusions. In patients receiving radiation therapy for esophageal cancer, proton plans are technically feasible while achieving adequate coverage with lower doses delivered to the lungs and cardiac structures. This may result in decreased cardiopulmonary toxicity and less morbidity to esophageal cancer patients. PMID:25489937

Corrigendum to "Long-term results of a phase II study of gemcitabine and cisplatin chemotherapy combined with intensity-modulated radiotherapy in locoregionally advanced nasopharyngeal carcinoma" [Oral Oncol. 73 (2017) 118-123].

PubMed

Wu, Mingyao; Ou, Dan; He, Xiayun; Hu, Chaosu

2017-11-01

To evaluate long-term results of a phase II study of induction and adjuvant gemcitabine and cisplatin (GP) chemotherapy with intensity-modulated radiotherapy (IMRT) in locoregionally advanced nasopharyngeal carcinoma (NPC). One hundred and twelve patients (Stage III: 65, IVA-B: 47) with locoregionally advanced NPC were enrolled in this study. All patients received induction chemotherapy consisting of 1000 mg/m 2 gemcitabine on day 1 and 8, and cisplatin 25 mg/m 2 on day 1-3, every 3 weeks for 2 cycles. Adjuvant chemotherapy for 2 cycles of the same regime was given 28 days after the end of IMRT. The IMRT technique was utilized for all patients. In total, 97.3% patients completed 2 cycles of induction chemotherapy. The overall response rate (RR) of cervical lymph nodes was 89.0%. Acute toxicities were mainly grade 1-2 myleosuppression and vomiting. And 83.9% patients completed 2 cycles of adjuvant chemotherapy. All patients finished IMRT with RR at the end of IMRT for nasopharynx, lymph nodes of neck and retropharyngeal area being 99.1%, 97.9% and 97.7%, respectively. The 5-year local control, regional control, distant metastasis-free and overall survival rates were 93.2%, 92.3%, 89.0% and 82.1%, respectively. The 5-year overall survival of stage III and IVA-B were 87.0%, and 75.5%, respectively. The incidence of grade 3-4 acute radiotherapy-related mucositis was 28.6%. Severe late toxicities were uncommon. IMRT combined with GP for locoregionally advanced NPC is well tolerated, effective, and convenient, and warrants further studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

SU-E-P-51: Dosimetric Comparison to Organs at Risk Sparing Using Volumetric-Modulated Arc Therapy Versus Intensity-Modulated Radiotherapy in Postoperative Radiotherapy of Left-Sided Breast Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiao, L; Deng, G; Xie, J

2015-06-15

Purpose: To compare the dosimetric characteristics of volumetric-modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) techniques in treatment planning for left-sided breast cancer patients with modified radical mastectomy. Methods: Twenty-four left-sided breast cancer patients treated with modified radical mastectomy were selected in this study. The planning target volume (PTV) was generated by using 7-mm uniform expansion of the clinical target volume (CTV) in all direction except the skin surface. The organs at risk (OARs) included heart, left lung, right lung, and right breast. Dose volume histograms (DVHs) were utilized to evaluate the dose distribution in PTV and OARs. Results: Bothmore » VMAT and IMRT plans met the requirement of PTV coverage. VMAT was superior to IMRT in terms of conformity, with a statistically significant difference (p=0.024). Mean doses, V5 and V10 of heart and both lungs in VMAT plans were significantly decreased compared to IMRT plans (P<0.05), but in terms of heart volume irradiated by high doses (V30 and V45), no significant differences were observed (P>0.05). For right breast, VMAT showed the reduction of V5 in comparison with IMRT (P<0.05). Additionally, the mean number of monitor units (MU) and treatment time in VMAT (357.21, 3.62 min) were significantly less than those in IMRT (1132.85, 8.74 min). Conclusion: VMAT showed similar PTV coverage and significant advantage in OARs sparing compared with IMRT, especially in terms of decreased volumes irradiated by low doses, while significantly reducing the treatment time and MU number.« less

The European Society of Therapeutic Radiology and Oncology-European Institute of Radiotherapy (ESTRO-EIR) report on 3D CT-based in-room image guidance systems: a practical and technical review and guide.

PubMed

Korreman, Stine; Rasch, Coen; McNair, Helen; Verellen, Dirk; Oelfke, Uwe; Maingon, Philippe; Mijnheer, Ben; Khoo, Vincent

2010-02-01

The past decade has provided many technological advances in radiotherapy. The European Institute of Radiotherapy (EIR) was established by the European Society of Therapeutic Radiology and Oncology (ESTRO) to provide current consensus statement with evidence-based and pragmatic guidelines on topics of practical relevance for radiation oncology. This report focuses primarily on 3D CT-based in-room image guidance (3DCT-IGRT) systems. It will provide an overview and current standing of 3DCT-IGRT systems addressing the rationale, objectives, principles, applications, and process pathways, both clinical and technical for treatment delivery and quality assurance. These are reviewed for four categories of solutions; kV CT and kV CBCT (cone-beam CT) as well as MV CT and MV CBCT. It will also provide a framework and checklist to consider the capability and functionality of these systems as well as the resources needed for implementation. Two different but typical clinical cases (tonsillar and prostate cancer) using 3DCT-IGRT are illustrated with workflow processes via feedback questionnaires from several large clinical centres currently utilizing these systems. The feedback from these clinical centres demonstrates a wide variability based on local practices. This report whilst comprehensive is not exhaustive as this area of development remains a very active field for research and development. However, it should serve as a practical guide and framework for all professional groups within the field, focussed on clinicians, physicists and radiation therapy technologists interested in IGRT. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

Utilization of cone-beam CT for offline evaluation of target volume coverage during prostate image-guided radiotherapy based on bony anatomy alignment.

PubMed

Paluska, Petr; Hanus, Josef; Sefrova, Jana; Rouskova, Lucie; Grepl, Jakub; Jansa, Jan; Kasaova, Linda; Hodek, Miroslav; Zouhar, Milan; Vosmik, Milan; Petera, Jiri

2012-01-01

To assess target volume coverage during prostate image-guided radiotherapy based on bony anatomy alignment and to assess possibility of safety margin reduction. Implementation of IGRT should influence safety margins. Utilization of cone-beam CT provides current 3D anatomic information directly in irradiation position. Such information enables reconstruction of the actual dose distribution. Seventeen prostate patients were treated with daily bony anatomy image-guidance. Cone-beam CT (CBCT) scans were acquired once a week immediately after bony anatomy alignment. After the prostate, seminal vesicles, rectum and bladder were contoured, the delivered dose distribution was reconstructed. Target dose coverage was evaluated by the proportion of the CTV encompassed by the 95% isodose. Original plans employed a 1 cm safety margin. Alternative plans assuming a smaller 7 mm margin between CTV and PTV were evaluated in the same way. Rectal and bladder volumes were compared with the initial ones. Rectal and bladder volumes irradiated with doses higher than 75 Gy, 70 Gy, 60 Gy, 50 Gy and 40 Gy were analyzed. In 12% of reconstructed plans the prostate coverage was not sufficient. The prostate underdosage was observed in 5 patients. Coverage of seminal vesicles was not satisfactory in 3% of plans. Most of the target underdosage corresponded to excessive rectal or bladder filling. Evaluation of alternative plans assuming a smaller 7 mm margin revealed 22% and 11% of plans where prostate and seminal vesicles coverage, respectively, was compromised. These were distributed over 8 and 7 patients, respectively. Sufficient dose coverage of target volumes was not achieved for all patients. Reducing of safety margin is not acceptable. Initial rectal and bladder volumes cannot be considered representative for subsequent treatment.

"Factors associated with non-small cell lung cancer treatment costs in a Brazilian public hospital".

PubMed

de Barros Reis, Carla; Knust, Renata Erthal; de Aguiar Pereira, Claudia Cristina; Portela, Margareth Crisóstomo

2018-02-17

The present study estimated the cost of advanced non-small cell lung cancer care for a cohort of 251 patients enrolled in a Brazilian public hospital and identified factors associated with the cost of treating the disease, considering sociodemographic, clinical and behavioral characteristics of patients, service utilization patterns and survival time. Estimates were obtained from the survey of direct medical cost per patient from the hospital's perspective. Data was collected from medical records and available hospital information systems. The ordinary least squares (OLS) method with logarithmic transformation of the dependent variable for the analysis of cost predictors was used to take into account the positive skewness of the costs distribution. The average cost of NSCLC was US$ 5647 for patients, with 71% of costs being associated to outpatient care. The main components of cost were daily hospital bed stay (22.6%), radiotherapy (15.5%) and chemotherapy (38.5%). The OLS model reported that, with 5% significance level, patients with higher levels of education, with better physical performance and less advanced disease have higher treatment costs. After controlling for the patient's survival time, only education and service utilization patterns were statistically significant. Individuals who were hospitalized or made use of radiotherapy or chemotherapy had higher costs. The use of these outpatient and hospital services explained most of the treatment cost variation, with a significant increase of the adjusted R 2 of 0.111 to 0.449 after incorporation of these variables in the model. The explanatory power of the complete model reached 62%. Inequities in disease treatment costs were observed, pointing to the need for strategies that reduce lower socioeconomic status and population's hurdles to accessing cancer care services.

Radiotherapy in Gorlin Syndrome: Can It Be Safe and Effective in Adult Patients?

PubMed

Baker, Sarah; Joseph, Kurian; Tai, Patricia

2016-01-01

Gorlin syndrome, also known as nevoid basal cell carcinoma syndrome, is a rare autosomal dominant disorder with multiple manifestations including early onset of cutaneous basal cell carcinomas (BCCs). Radiotherapy has traditionally been contraindicated due to reports of BCC induction. We describe here a patient treated successfully with radiotherapy with no tumour induction at 57 months of follow-up. A comprehensive literature review of radiotherapy outcomes in patients with Gorlin syndrome suggests radiotherapy may be a feasible treatment option for adult patients with treatment refractory lesions or surgical contraindication. © The Author(s) 2015.

Dose constraints for moderate hypofractionated radiotherapy for prostate cancer: The French genito-urinary group (GETUG) recommendations.

PubMed

Langrand-Escure, J; de Crevoisier, R; Llagostera, C; Créhange, G; Delaroche, G; Lafond, C; Bonin, C; Bideault, F; Sargos, P; Belhomme, S; Pasquier, D; Latorzeff, I; Supiot, S; Hennequin, C

2018-04-01

Considering recent phase III trials results, moderate hypofractionated radiotherapy can be considered as a standard treatment for low and intermediate risk prostate cancer management. This assessment call for a framework allowing homogeneous and reproducible practices in the different centers using this radiotherapy schedule. The French Genito-Urinary Group (GETUG) provides here recommendations for daily practice of moderate hypofractionated radiotherapy for prostate cancer, with indications, dose, fractionation, pre-treatment planning, volume of interest delineation (target volume and organs at risk) and margins, dose constraints and radiotherapy techniques. Copyright © 2018. Published by Elsevier SAS.

Precision medicine and molecular imaging: new targeted approaches toward cancer therapeutic and diagnosis.

PubMed

Ghasemi, Mojtaba; Nabipour, Iraj; Omrani, Abdolmajid; Alipour, Zeinab; Assadi, Majid

2016-01-01

This paper presents a review of the importance and role of precision medicine and molecular imaging technologies in cancer diagnosis with therapeutics and diagnostics purposes. Precision medicine is progressively becoming a hot topic in all disciplines related to biomedical investigation and has the capacity to become the paradigm for clinical practice. The future of medicine lies in early diagnosis and individually appropriate treatments, a concept that has been named precision medicine, i.e. delivering the right treatment to the right patient at the right time. Molecular imaging is quickly being recognized as a tool with the potential to ameliorate every aspect of cancer treatment. On the other hand, emerging high-throughput technologies such as omics techniques and systems approaches have generated a paradigm shift for biological systems in advanced life science research. In this review, we describe the precision medicine, difference between precision medicine and personalized medicine, precision medicine initiative, systems biology/medicine approaches (such as genomics, radiogenomics, transcriptomics, proteomics, and metabolomics), P4 medicine, relationship between systems biology/medicine approaches and precision medicine, and molecular imaging modalities and their utility in cancer treatment and diagnosis. Accordingly, the precision medicine and molecular imaging will enable us to accelerate and improve cancer management in future medicine.

Precision medicine and molecular imaging: new targeted approaches toward cancer therapeutic and diagnosis

PubMed Central

Ghasemi, Mojtaba; Nabipour, Iraj; Omrani, Abdolmajid; Alipour, Zeinab; Assadi, Majid

2016-01-01

This paper presents a review of the importance and role of precision medicine and molecular imaging technologies in cancer diagnosis with therapeutics and diagnostics purposes. Precision medicine is progressively becoming a hot topic in all disciplines related to biomedical investigation and has the capacity to become the paradigm for clinical practice. The future of medicine lies in early diagnosis and individually appropriate treatments, a concept that has been named precision medicine, i.e. delivering the right treatment to the right patient at the right time. Molecular imaging is quickly being recognized as a tool with the potential to ameliorate every aspect of cancer treatment. On the other hand, emerging high-throughput technologies such as omics techniques and systems approaches have generated a paradigm shift for biological systems in advanced life science research. In this review, we describe the precision medicine, difference between precision medicine and personalized medicine, precision medicine initiative, systems biology/medicine approaches (such as genomics, radiogenomics, transcriptomics, proteomics, and metabolomics), P4 medicine, relationship between systems biology/medicine approaches and precision medicine, and molecular imaging modalities and their utility in cancer treatment and diagnosis. Accordingly, the precision medicine and molecular imaging will enable us to accelerate and improve cancer management in future medicine. PMID:28078184

A prospective, longitudinal study to evaluate the clinical utility of a predictive algorithm that detects risk of opioid use disorder.

PubMed

Brenton, Ashley; Lee, Chee; Lewis, Katrina; Sharma, Maneesh; Kantorovich, Svetlana; Smith, Gregory A; Meshkin, Brian

2018-01-01

The purpose of this study was to determine the clinical utility of an algorithm-based decision tool designed to assess risk associated with opioid use. Specifically, we sought to assess how physicians were using the profile in patient care and how its use affected patient outcomes. A prospective, longitudinal study was conducted to assess the utility of precision medicine testing in 5,397 patients across 100 clinics in the USA. Using a patent-protected, validated algorithm combining specific genetic risk factors with phenotypic traits, patients were categorized into low-, moderate-, and high-risk patients for opioid abuse. Physicians who ordered precision medicine testing were asked to complete patient evaluations and document their actions, decisions, and perceptions regarding the utility of the precision medicine tests. The patient outcomes associated with each treatment action were carefully documented. Physicians used the profile to guide treatment decisions for over half of the patients. Of those, guided treatment decisions for 24.5% of the patients were opioid related, including changing the opioid prescribed, starting an opioid, or titrating a patient off the opioid. Treatment guidance was strongly influenced by profile-predicted opioid use disorder (OUD) risk. Most importantly, patients whose physicians used the profile to guide opioid-related treatment decisions had improved clinical outcomes, including better pain management by medication adjustments, with an average pain decrease of 3.4 points on a scale of 1-10. Patients whose physicians used the profile to guide opioid-related treatment decisions had improved clinical outcomes, as measured by decreased pain levels resulting from better pain management with prescribed medications. The clinical utility of the profile is twofold. It provides clinically actionable recommendations that can be used to 1) prevent OUD through limiting initial opioid prescriptions and 2) reduce pain in patients at low risk of developing OUD.

A prospective, longitudinal study to evaluate the clinical utility of a predictive algorithm that detects risk of opioid use disorder

PubMed Central

Brenton, Ashley; Lee, Chee; Lewis, Katrina; Sharma, Maneesh; Kantorovich, Svetlana; Smith, Gregory A; Meshkin, Brian

2018-01-01

Purpose The purpose of this study was to determine the clinical utility of an algorithm-based decision tool designed to assess risk associated with opioid use. Specifically, we sought to assess how physicians were using the profile in patient care and how its use affected patient outcomes. Patients and methods A prospective, longitudinal study was conducted to assess the utility of precision medicine testing in 5,397 patients across 100 clinics in the USA. Using a patent-protected, validated algorithm combining specific genetic risk factors with phenotypic traits, patients were categorized into low-, moderate-, and high-risk patients for opioid abuse. Physicians who ordered precision medicine testing were asked to complete patient evaluations and document their actions, decisions, and perceptions regarding the utility of the precision medicine tests. The patient outcomes associated with each treatment action were carefully documented. Results Physicians used the profile to guide treatment decisions for over half of the patients. Of those, guided treatment decisions for 24.5% of the patients were opioid related, including changing the opioid prescribed, starting an opioid, or titrating a patient off the opioid. Treatment guidance was strongly influenced by profile-predicted opioid use disorder (OUD) risk. Most importantly, patients whose physicians used the profile to guide opioid-related treatment decisions had improved clinical outcomes, including better pain management by medication adjustments, with an average pain decrease of 3.4 points on a scale of 1–10. Conclusion Patients whose physicians used the profile to guide opioid-related treatment decisions had improved clinical outcomes, as measured by decreased pain levels resulting from better pain management with prescribed medications. The clinical utility of the profile is twofold. It provides clinically actionable recommendations that can be used to 1) prevent OUD through limiting initial opioid prescriptions and 2) reduce pain in patients at low risk of developing OUD. PMID:29379313

Utilization of PET-CT in target volume delineation for three-dimensional conformal radiotherapy in patients with non-small cell lung cancer and atelectasis.

PubMed

Yin, Li-Jie; Yu, Xiao-Bin; Ren, Yan-Gang; Gu, Guang-Hai; Ding, Tian-Gui; Lu, Zhi

2013-03-18

To investigate the utilization of PET-CT in target volume delineation for three-dimensional conformal radiotherapy in patients with non-small cell lung cancer (NSCLC) and atelectasis. Thirty NSCLC patients who underwent radical radiotherapy from August 2010 to March 2012 were included in this study. All patients were pathologically confirmed to have atelectasis by imaging examination. PET-CT scanning was performed in these patients. According to the PET-CT scan results, the gross tumor volume (GTV) and organs at risk (OARs, including the lungs, heart, esophagus and spinal cord) were delineated separately both on CT and PET-CT images. The clinical target volume (CTV) was defined as the GTV plus a margin of 6-8 mm, and the planning target volume (PTV) as the GTV plus a margin of 10-15mm. An experienced physician was responsible for designing treatment plans PlanCT and PlanPET-CT on CT image sets. 95% of the PTV was encompassed by the 90% isodose curve, and the two treatment plans kept the same beam direction, beam number, gantry angle, and position of the multi-leaf collimator as much as possible. The GTV was compared using a target delineation system, and doses distributions to OARs were compared on the basis of dose-volume histogram (DVH) parameters. The GTVCT and GTVPET-CT had varying degrees of change in all 30 patients, and the changes in the GTVCT and GTVPET-CT exceeded 25% in 12 (40%) patients. The GTVPET-CT decreased in varying degrees compared to the GTVCT in 22 patients. Their median GTVPET-CT and median GTVPET-CT were 111.4 cm3 (range, 37.8 cm3-188.7 cm3) and 155.1 cm3 (range, 76.2 cm3-301.0 cm3), respectively, and the former was 43.7 cm3 (28.2%) less than the latter. The GTVPET-CT increased in varying degrees compared to the GTVCT in 8 patients. Their median GTVPET-CT and median GTVPET-CT were 144.7 cm3 (range, 125.4 cm3-178.7 cm3) and 125.8 cm3 (range, 105.6 cm3-153.5 cm3), respectively, and the former was 18.9 cm3 (15.0%) greater than the latter. Compared to PlanCT parameters, PlanPET-CT parameters showed varying degrees of changes. The changes in lung V20, V30, esophageal V50 and V55 were statistically significant (Ps< 0.05 for all), while the differences in mean lung dose, lung V5, V10, V15, heart V30, mean esophageal dose, esophagus Dmax, and spinal cord Dmax were not significant (Ps> 0.05 for all). PET-CT allows a better distinction between the collapsed lung tissue and tumor tissue, improving the accuracy of radiotherapy target delineation, and reducing radiation damage to the surrounding OARs in NSCLC patients with atelectasis.

Omission of Breast Radiotherapy in Low-risk Luminal A Breast Cancer: Impact on Health Care Costs.

PubMed

Han, K; Yap, M L; Yong, J H E; Mittmann, N; Hoch, J S; Fyles, A W; Warde, P; Gutierrez, E; Lymberiou, T; Foxcroft, S; Liu, F F

2016-09-01

The economic burden of cancer care is substantial, including steep increases in costs for breast cancer management. There is mounting evidence that women age ≥ 60 years with grade I/II T1N0 luminal A (ER/PR+, HER2- and Ki67 ≤ 13%) breast cancer have such low local recurrence rates that adjuvant breast radiotherapy might offer limited value. We aimed to determine the total savings to a publicly funded health care system should omission of radiotherapy become standard of care for these patients. The number of women aged ≥ 60 years who received adjuvant radiotherapy for T1N0 ER+ HER2- breast cancer in Ontario was obtained from the provincial cancer agency. The cost of adjuvant breast radiotherapy was estimated through activity-based costing from a public payer perspective. The total saving was calculated by multiplying the estimated number of luminal A cases that received radiotherapy by the cost of radiotherapy minus Ki-67 testing. In 2010, 748 women age ≥ 60 years underwent surgery for pT1N0 ER+ HER2- breast cancer; 539 (72%) underwent adjuvant radiotherapy, of whom 329 were estimated to be grade I/II luminal A subtype. The cost of adjuvant breast radiotherapy per case was estimated at $6135.85; the cost of Ki-67 at $114.71. This translated into an annual saving of about $2.0million if radiotherapy was omitted for all low-risk luminal A breast cancer patients in Ontario and $5.1million across Canada. There will be significant savings to the health care system should omission of radiotherapy become standard practice for women with low-risk luminal A breast cancer. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Locally Advanced Stage IV Squamous Cell Carcinoma of the Head and Neck: Impact of Pre-Radiotherapy Hemoglobin Level and Interruptions During Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rades, Dirk; Department of Radiation Oncology, University Medical Center Hamburg-Eppendorf, Hamburg; Stoehr, Monika

2008-03-15

Purpose: Stage IV head and neck cancer patients carry a poor prognosis. Clear understanding of prognostic factors can help to optimize care for the individual patient. This study investigated 11 potential prognostic factors including pre-radiotherapy hemoglobin level and interruptions during radiotherapy for overall survival (OS), metastases-free survival (MFS), and locoregional control (LC) after radiochemotherapy. Methods and Materials: Eleven factors were investigated in 153 patients receiving radiochemotherapy for Stage IV squamous cell head and neck cancer: age, gender, Karnofsky performance score (KPS), tumor site, grading, T stage, N stage, pre-radiotherapy hemoglobin level, surgery, chemotherapy type, and interruptions during radiotherapy >1 week.more » Results: On multivariate analysis, improved OS was associated with KPS 90-100 (relative risk [RR], 2.36; 95% confidence interval [CI], 1.20-4.93; p = .012), hemoglobin {>=}12 g/dL (RR, 1.88; 95% CI, 1.01-3.53; p = .048), and no radiotherapy interruptions (RR, 2.59; 95% CI, 1.15-5.78; p = .021). Improved LC was significantly associated with lower T stage (RR, 2.17; 95% CI, 1.16-4.63; p = .013), hemoglobin {>=}12 g/dL (RR, 4.12; 95% CI, 1.92-9.09; p < .001), surgery (RR, 2.67; 95% CI, 1.28-5.88; p = .008), and no radiotherapy interruptions (RR, 3.32; 95% CI, 1.26-8.79; p = .015). Improved MFS was associated with KPS 90-100 (RR, 3.41; 95% CI, 1.46-8.85; p = .012). Conclusions: Significant predictors for outcome in Stage IV head and neck cancer were performance status, stage, surgery, pre-radiotherapy hemoglobin level, and interruptions during radiotherapy >1 week. It appears important to avoid anemia and radiotherapy interruptions to achieve the best treatment results.« less

The Benefits of Providing External Beam Radiotherapy in Low- and Middle-income Countries.

PubMed

Yap, M L; Hanna, T P; Shafiq, J; Ferlay, J; Bray, F; Delaney, G P; Barton, M

2017-02-01

More than half of all cancer diagnoses worldwide occur in low- and middle-income countries (LMICs) and the incidence is projected to rise substantially within the next 20 years. Radiotherapy is a vital, cost-effective treatment for cancer; yet there is currently a huge deficit in radiotherapy services within these countries. The aim of this study was to estimate the potential outcome benefits if external beam radiotherapy was provided to all patients requiring such treatment in LMICs, according to the current evidence-based guidelines. Projected estimates of these benefits were calculated to 2035, obtained by applying the previously published Collaboration for Cancer Outcomes, Research and Evaluation (CCORE) demand and outcome benefit estimates to cancer incidence and projection data from the GLOBOCAN 2012 data. The estimated optimal radiotherapy utilisation rate for all LMICs was 50%. There were about 4.0 million cancer patients in LMICs who required radiotherapy in 2012. This number is projected to increase by 78% by 2035, a far steeper increase than the 38% increase expected in high-income countries. National radiotherapy benefits varied widely, and were influenced by case mix. The 5 year population local control and survival benefits for all LMICs, if radiotherapy was delivered according to guidelines, were estimated to be 9.6% and 4.4%, respectively, compared with no radiotherapy use. This equates to about 1.3 million patients who would derive a local control benefit in 2035, whereas over 615 000 patients would derive a survival benefit if the demand for radiotherapy in LMICs was met. The potential outcome benefits were found to be higher in LMICs. These results further highlight the urgent need to reduce the gap between the supply of, and demand for, radiotherapy in LMICs. We must attempt to address this 'silent crisis' as a matter of priority and the approach must consider the complex societal challenges unique to LMICs. Copyright © 2016 The Royal College of Radiologists. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Magallanes, L., E-mail: lorena.magallanes@med.uni-heidelberg.de; Rinaldi, I., E-mail: ilaria.rinaldi@med.uni-heidelberg.de; Brons, S., E-mail: stephan.brons@med.uni-heidelberg.de

External beam radiotherapy techniques have the common aim to maximize the radiation dose to the target while sparing the surrounding healthy tissues. The inverted and finite depth-dose profile of ion beams (Bragg peak) allows for precise dose delivery and conformai dose distribution. Furthermore, increased radiobiological effectiveness of ions enhances the capability to battle radioresistant tumors. Ion beam therapy requires a precise determination of the ion range, which is particularly sensitive to range uncertainties. Therefore, novel imaging techniques are currently investigated as a tool to improve the quality of ion beam treatments. Approaches already clinically available or under development are basedmore » on the detection of secondary particles emitted as a result of nuclear reactions (e.g., positron-annihilation or prompt gammas, charged particles) or transmitted high energy primary ion beams. Transmission imaging techniques make use of the beams exiting the patient, which have higher initial energy and lower fluence than the therapeutic ones. At the Heidelberg Ion Beam Therapy Center, actively scanned energetic proton and carbon ion beams provide an ideal environment for the investigation of ion-based radiography and tomography. This contribution presents the rationale of ion beam therapy, focusing on the role of ion-based transmission imaging methods towards the reduction of range uncertainties and potential improvement of treatment planning.« less

Hyperthermia and radiotherapy in the management of head and neck cancers: A systematic review and meta-analysis.

PubMed

Datta, Niloy R; Rogers, Susanne; Ordóñez, Silvia Gómez; Puric, Emsad; Bodis, Stephan

2016-01-01

A systematic review and meta-analysis was conducted to evaluate the outcome of controlled clinical trials in head and neck cancers (HNCs) using hyperthermia and radiotherapy versus radiotherapy alone. A total of 498 abstracts were screened from four databases and hand searched as per the PRISMA guidelines. Only two-arm studies treating HNCs with either radiotherapy alone, or hyperthermia and radiotherapy without concurrent chemotherapy or surgery were considered. The evaluated end point was complete response (CR). Following a detailed screening of the titles, abstracts and full text papers, six articles fulfilling the above eligibility criteria were considered. In total 451 clinical cases from six studies were included in the meta-analysis. Five of six trials were randomised. The overall CR with radiotherapy alone was 39.6% (92/232) and varied between 31.3% and 46.9% across the six trials. With thermoradiotherapy, the overall CR reported was 62.5% (137/219), (range 33.9-83.3%). The odds ratio was 2.92 (95% CI: 1.58-5.42, p = 0.001); the risk ratio was 1.61 (95% CI: 1.32-1.97, p < 0.0001) and the risk difference was 0.25 (95% CI: 0.12-0.39, p < 0.0001), all in favour of combined treatment with hyperthermia and radiotherapy over radiotherapy alone. Acute and late grade III/IV toxicities were reported to be similar in both the groups. Hyperthermia along with radiotherapy enhances the likelihood of CR in HNCs by around 25% compared to radiotherapy alone with no significant additional acute and late morbidities. This level I evidence should justify the integration of hyperthermia into the multimodality therapy of HNCs.

Green tea extract (epigallocatechin-3-gallate) reduces efficacy of radiotherapy on prostate cancer cells.

PubMed

Thomas, Francis; Holly, Jeff M P; Persad, Rajendra; Bahl, Amit; Perks, Claire M

2011-08-01

To assess the influence of epigallocatechin-3-gallate (EGCG) on the efficacy of ionizing radiation on prostate cancer cells because of the increased use of dietary interventions, especially by patients with prostate cancer. Radiotherapy is used to treat localized prostate cancer. Some people consume green tea (EGCG) as a chemopreventive agent against prostate cancer. Green tea can act as an antioxidant and induce superoxide dismutase enzymes, which could scavenge the free oxygen radicals generated by radiotherapy. Prostate cancer cell line DU145 cells were treated with EGCG or radiotherapy, or both. Cell death was assessed using trypan blue cell counting, and apoptosis was confirmed by assessing poly (adenosine phosphate ribose) polymerase cleavage. The antioxidant potential was assessed using Western immunoblotting for manganese superoxide dismutase and copper zinc superoxide dismutase enzymes. Radiotherapy was delivered using a linear accelerator. Cell cycle analysis was performed using flow cytometry. Radiotherapy at 3.5 Gy induced a 5.9-fold increase in apoptosis of DU145 cells. Subapoptotic doses of EGCG (1.5-7.5 μM) significantly reduced ionizing radiation-induced apoptosis (P < .001), with the inhibitory effect of EGCG on ionizing radiation being most effective when added 30 minutes before radiotherapy (P < .001). In addition, when radiotherapy and EGCG were used together, an approximate 1.5-fold increase in manganese superoxide dismutase levels was seen compared with the control and a 2-fold increase compared with radiotherapy alone. Radiotherapy is effective in inducing apoptosis in DU145 cells, but its effect was significantly reduced in the presence of EGCG, and this was associated with an increase in the induction of manganese superoxide dismutase. Copyright © 2011 Elsevier Inc. All rights reserved.

Adjuvant radiotherapy after transoral laser microsurgery for advanced squamous carcinoma of the head and neck

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pradier, Olivier; Christiansen, Hans; Schmidberger, Heinz

Purpose: To evaluate the efficacy of an adjuvant radiotherapy after transoral laser microsurgery for advanced squamous cell carcinoma of the head and neck and to show that a less invasive surgery with organ preservation in combination with radiotherapy is an alternative to a radical treatment. Patients and Methods: Between 1987 and 2000, 208 patients with advanced squamous cell carcinoma of the head and neck were treated with postoperative radiotherapy after surgical CO{sub 2} laser resection. Primary sites included oral cavity, 38; oropharynx, 88; larynx, 36; hypopharynx, 46. Disease stages were as follows: Stage III, 40 patients; Stage IV, 168 patients.more » Before 1994, the treatment consisted of a split-course radiotherapy with carboplatinum (Treatment A). After 1994, the patients received a conventional radiotherapy (Treatment B). Results: Patients had 5-year locoregional control and disease-specific survival (DSS) rates of 68% and 48%, respectively. The 5-year DSS was 70% and 44% for Stages III and IV, respectively (p = 0.00127). Patients treated with a hemoglobin level greater or equal to 13.5 g/dL before radiotherapy had a 5-year DSS of 55% as compared with 39% for patients treated with a hemoglobin level greater than 13.5 g/dL (p = 0.0054). Conclusion: In this series of patients with advanced head-and-neck tumors, transoral laser surgery in combination with adjuvant radiotherapy resulted in locoregional control and DSS rates similar to those reported for radical surgery followed by radiotherapy. Treatment B has clearly been superior to Treatment A. A further improvement of our treatment regimen might be expected by the combination of adjuvant radiotherapy with concomitant platinum-based chemotherapy.« less

Radiotherapy for ductal carcinoma in situ and risk of second non-breast cancers.

PubMed

Withrow, Diana R; Morton, Lindsay M; Curtis, Rochelle E; Schonfeld, Sara J; Berrington de González, Amy

2017-11-01

Radiotherapy for ductal carcinoma (DCIS) is increasing, but the risks and benefits of the treatment remain uncertain. We aimed to investigate the relationship between radiotherapy for DCIS and risk of second non-breast cancers in a large US cohort. We conducted a retrospective cohort study of 52,556 women in 12 U.S. population-based cancer registries diagnosed with first primary DCIS during 1992-2008 at age 25-79 years. We estimated relative risks (RRs), attributable risks (AR), and excess absolute risks (EAR) of second non-breast cancers associated with radiotherapy using Poisson regression adjusted for age at year of diagnosis, grade, hormonal therapy (yes/no or unknown), and time since diagnosis. Approximately half of the women (46.3%) received radiotherapy. Radiotherapy was associated with an increased risk of all second non-breast cancers combined [RR 1.17, 95% confidence interval (CI) 1.08-1.28] and all in-field, radiation-related second cancers combined (RR 1.37, 95% CI 1.15-1.63), driven by second lung cancers (RR 1.33, 95% CI 1.10-1.60) and non-CLL leukemia (RR 1.71, 95% CI 1.02-2.86). The estimated cumulative excess risk of all second non-breast cancers was 0.8% by 15 years after DCIS diagnosis. Radiotherapy was associated with an increased risk of second non-breast cancers. The specific excess of cancers at sites likely in/near the radiotherapy field suggests the findings are unlikely due exclusively to confounding, but further research into factors related to receipt of radiotherapy is needed. Our risk estimates can be used to help assess the balance of the risks and benefits of radiotherapy for DCIS and to inform clinical practice.

Long-Term Counterinsurgency Strategy: Maximizing Special Operations and Airpower

DTIC Science & Technology

2010-02-01

operations forces possess a repertoire of capabilities and attributes which impart them with unique strategic utility. “That utility reposes most...flashlight), LTMs are employed in a similar role to cue aircrews equipped with Night Vision Devices (NVDs). Concurrently, employment of small laptop...Special Operations Forces (PSS-SOF) and Precision Fires Image Generator (PFIG) have brought similar benefit to the employment of GPS/INS targeted weapons