OBJECTIVES: Concurrent chemoradiotherapy in well-selected locally advanced non-small cell lung cancer (LANSCLC) is considered as standard therapy. However, the choice of anticancer agents is still unresolved. Our objectives were to determine the maximum tolerated dose and recommended dose of pemetrexed in combination with cisplatin, with concurrent late course accelerated ...
PubMed
Continuous, hyperfractionated, accelerated radiotherapy (CHART) was devised to give the maximum chance of improving clinical radiotherapy and was based upon available radiobiological evidence. A pilot study, begun in 1985, has now included 210 patients. When comparison is made with previously treated cases, improved results have been seen in the two main ...
This paper reviews the use of hyperfractionated and/or accelerated radiation therapy in the curative treatment of non-small cell lung cancer, and explains the scientific rationale behind the development of these regimes. The indications, practicalities and economics of introducing them routinely are addressed. Novel radiotherapy techniques are further ...
PubMed Central
Continuous, hyperfractionated, accelerated radiotherapy (CHART) has given high levels of tumour control in advanced head and neck and bronchial carcinomas. In general, late changes have appeared less than after conventional radiotherapy but despite a prediction of reduced risk of spinal cord damage, two cases of radiation myelitis have presented. The ...
Treatment with several doses per day offers the prospect of a significant therapeutic gain using readily available low LET beams. These regimens can be classified as either accelerated fractionation or hyperfractionation according to their rationales. With accelerated fractionation a conventional number of dose fractions is delivered ...
Energy Citations Database
Purpose: We previously demonstrated that intensity-modulated radiation therapy (IMRT) significantly improves radiation dose distribution over three-dimensional planning for nasopharynx cancer and reported positive early clinical results. We now evaluate whether IMRT has resulted in improved outcomes for a larger cohort of patients with longer follow-up. ...
This work reports an investigation on the reliability, accuracy, and efficiency of gated intensity modulated radiation therapy (IMRT) delivery with a commercial linear accelerator. The dosimetry measurements of segmented multileaf collimated IMRT (SMLC-IMRT) were performed by using radiographic films and a ...
Between May 1993 and January 1995, 36 patients with high-grade astrocytomas were treated with 1.05 Gy continuous hyperfractionated accelerated radiotherapy three times daily to a total target dose of 59.85 Gy in 19 days with 6-h intervals. The median age of the patients was 51 years and the median follow-up was 58 weeks. The median survival rate was 58 ...
... time, a significant gain can be obtained for non-small cell lung cancer (18). Also, in head and neck cancer, improved ... hyperfractionated accelerated radiotherapy (CHART) versus conventional radiotherap...
NBII National Biological Information Infrastructure
Most IMRT techniques have been designed to treat targets smaller than the field size of conventional linac accelerators. In order to overcome the field size restrictions in applying IMRT, we developed a two isocenter IMRT technique to treat long volume targets. The technique exploits an extended dose gradient ...
NASA Astrophysics Data System (ADS)
Based on the assumption that an accelerated proliferation process prevails in tumour cell residues after surgery, the possibility that treatment acceleration would offer a therapeutic advantage in postoperative radiotherapy of locally advanced head and neck cancer was investigated. The value of Tpot in predicting the treatment ...
Purpose: Reirradiation (re-RT) of recurrent head and neck cancer (HNC) may achieve long-term disease control in some patients, at the expense of high rates of late sequelae. Limiting the re-RT targets to the recurrent gross tumor volume (rGTV) would reduce the volumes of reirradiated tissues; however, its effect on tumor recurrence pattern is unknown. Methods and Materials: This is a retrospective ...
This study aimed to establish the feasibility of intensity-modulated radiation therapy (IMRT) in craniospinal irradiation (CSI) using conventional linear accelerator (IMRT_LA) and compare it dosimetrically with helical TomoTherapy (IMRT_Tomo) and three-dimensional conformal radiotherapy (3DCRT). CT datasets of four ...
In this brief letter the arguments of Sherouse in 2002, that the delivery of intensity-modulated radiation therapy (IMRT) does not necessarily require a multileaf collimator (MLC), are extended with specific reference to the possibility to use the jaws-only (JO) of an accelerator or some moving mask. With reference to the work in the last decade to develop ...
This book contains 16 selections. Some of the titles are: Some Changes in Dose Fractionation over 20 Years; Time, Dose and Fractionation in Radiation Therapy: An Historical Perspective; Twice-Daily Radiation Therapy for Head and Neck Carcinomas; Accelerated Repopulation in Head and Neck Cancer; and Accelerated Hyperfractionation ...
The state of the art Intensity Modulate Radiation Therapy (IMRT) has been one of the most significant breakthroughs in the cancer treatment in the past 30 years. There are two types of IMRT systems. The first system is the binary-based tomotherapy, represented by the Peacock (Nomos Corp) and Tomo unit (TomoTherapy Inc.), adopting specific binary collimator ...
IMRT is frequently used in the head-and-neck region, which contains materials of widely differing densities (soft tissue, bone, air-cavities). Conventional methods of dose computation for these complex, inhomogeneous IMRT cases involve significant approximations. In the present work, a methodology for the development, commissioning and implementation of a ...
In intensity-modulated radiation therapy (IMRT), the aim is to deliver reduced doses of radiation to normal tissue. As a step toward IMRT, we examined dynamic optical modulation of an electron beam produced by a photocathode RF gun. Images on photomasks were transferred onto a photocathode by relay imaging. The resulting beam was controlled by a remote ...
cancer can tol- erate curative RT,^'^ even concurrent chemotherapy and accelerated hyperfractionated is quite low." Analyses in patients who refuse surgery but who are otherwise good operative candidates show for prolonged courses of RT or chemotherapy.'" Prostate Seed Implants Prostate "seed" implantation is a form
E-print Network
Purpose: To evaluate the toxicity and efficacy of accelerated hyperfractionated radiotherapy (RT) for locally advanced cervical cancer. Methods and Materials: A multi-institutional prospective single-arm study was conducted among eight Asian countries. Between 1999 and 2002, 120 patients (64 with Stage IIB and 56 with Stage IIIB) with squamous cell ...
The beam-on time for intensity modulated radiation therapy (IMRT) is increased significantly compared with conventional radiotherapy treatments. Further, the presence of beam modulation devices may potentially affect neutron production. Therefore, neutron measurements were performed for 15 MV photon beams on a Varian Clinac accelerator to determine the ...
DOE Information Bridge
Approximately 40-50% of children with cancer will be irradiated during their treatment. Intensity-modulated radiotherapy (IMRT) by linear accelerator or helical tomotherapy improves dose distribution in target volumes and normal tissue sparing. This technology could be particularly useful for pediatric patients to achieve an optimal dose distribution in ...
The 2D ionization chamber array I'mRT MatriXX (IBA, Schwarzenbruck, Germany) has been developed for absolute 2D dosimetry and verification of intensity-modulated radiation therapy (IMRT) for perpendicular beam incidence. The aim of this study is to evaluate the applicability of I'mRT MatriXX for oblique beam incidence and hybrid plan ...
The possibility of reduced cell kill following intensity-modulated radiation therapy (IMRT) compared to conventional radiation therapy has been debated in the literature. This potential reduction in cell kill relates to prolonged treatment times typical of IMRT dose delivery and consequently increased repair of sublethal lesions. While there is some ...
Purpose: Out-of-field radiation doses to normal tissues may be associated with an increased risk of secondary malignancies, particularly in long-term survivors. Step-and-shoot intensity-modulated radiation therapy (IMRT), an increasingly popular treatment modality, yields higher out-of-field doses than do conventional treatments, because of an increase in required monitor ...
There is a well-established role for radiation treatment in the management of non-small cell lung cancer. As a single modality, it is indicated as a radical treatment option for patients deemed unsuitable for chemotherapy with inoperable locoregional disease or who decline surgery. In this patient group, the evidence shows advantages for accelerated treatment regimes, e.g. ...
BackgroundRecent developments enable to deliver rotational IMRT with standard C-arm gantry based linear accelerators. This upcoming treatment technique was benchmarked in a multi-center treatment planning study against static gantry IMRT and rotational IMRT based on a ring gantry for a complex parotid gland sparing ...
Intensity-modulated radiation therapy (IMRT) is essential to have a dose distribution matching with the planning target volume (PTV) in case of concave-shape target. Today IMRT delivery techniques with linear accelerator can be divided into two classes: techniques with fixed gantry, called "step and shoot" (S&S) and "sliding ...
This study is an attempt to compare the dosimetric parameters of intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery (SRS) using patient data. Radiosurgery was delivered through circular tertiary collimators attached to a linear accelerator. Six patients who were treated with SRS were replanned and evaluated with the ...
Radical radiotherapy, the mainstay of treatment for early inoperable non-small-cell lung cancer, is most commonly given in daily fractions, Monday to Friday, to a total dose of 60-70 Gy over 6-8 weeks. Since the 1980s, novel fractionation schedules have been explored with the aim of improving local tumour control and survival without increasing late morbidity. There have been two main approaches. ...
A comparison was made of the morbidity of surgery for loco-regional recurrence in patients with advanced cancer of the head and neck region following continuous hyperfractionated accelerated radiotherapy (CHART), after conventional radiotherapy, and also in a group following surgery only as the primary treatment. Post-surgical morbidity occurred in 14 ...
There is some controversy over the need for double data entry in clinical trials. In particular, does the number and types of errors identified with this approach justify the extra effort involved? We report the results of a study carried out to address this question. Our main outcome measure was the frequency and types of errors involved in the entry of data for the CHART (continuous, ...
Between January 1985 and December 1988, 62 patients with locally advanced carcinoma of the bronchus were treated by radiotherapy using continuous, hyperfractionated, accelerated radiotherapy (CHART). With this regime on each of 12 consecutive days 3 fractions were given with a time interval of 6 hr between each. Initially a dose fraction of 1.4 Gy was used ...
Twenty-one patients with squamous cell carcinoma of the nasal columella and vestibule were treated at the Mount Vernon Centre for Cancer Treatment between March 1986 and January 1994. Tumours ranged from 15 to 55 mm in maximum dimension (median 25 mm). All patients were treated with radical intent with continuous hyperfractionated accelerated radiotherapy ...
Experience using accelerated hyperfractionation radiation therapy (twice-a-day) in the treatment of 60 patients with squamous cell carcinoma of the nasopharynx is presented. The local control rate at the primary sites was significantly improved statistically as compared with 58 patients with the same disease and stages treated by once daily (once-a-day) ...
Dosimetry verification is an important step during intensity modulated radiotherapy treatment (IMRT). The verification is usually conducted with measurements and independent dose calculations. However, currently available independent dose calculation methods were developed for step-and-shoot beam delivery methods, and their uses for dynamic multi-leaf collimator (MLC) delivery ...
We investigated protection strategies of organs at risk (OARs) in intensity modulated radiation therapy (IMRT). These strategies apply to delivery of IMRT to moving body anatomies that show relative displacement of OAR in close proximity to a tumor target. We formulated an efficient genetic algorithm which makes it possible to search for global minima in a ...
Purpose: Late course accelerated hyperfractionated (LCAF) radiotherapy (RT) is as effective as standard chemoradiotherapy for nonsurgical management of locally advanced esophageal squamous cell carcinoma (SCC). We have evaluated further the efficacy of concurrent LCAF RT and chemotherapy. Methods and Materials: In all, 111 eligible patients with esophageal ...
Objectives: To evaluate the efficacy and treatment-related toxicity of accelerated hyperfractionation field-involved re-irradiation combined with concurrent capecitabine chemotherapy for locally recurrent and irresectable rectal cancer (LRIRC). Methods: 72 patients with LRIRC who underwent the treatment were studied. Three-dimensional conformal ...
Overall time is important in the curative treatment of head and neck cancer (Dische, S., Saunders, M.I., Barrett, A., Harvey, A., Gibson, D., Parmar, M., 1997, Radiother. Oncol., 44:123-136). Results are presented on outcome and morbidity in ten patients with head and neck cancer treated with external beam irradiation (CHART protocol) and interstitial implantation, completing treatment in 12 days. ...
Purpose: To retrospectively determine rates of toxicity, freedom from local progression, and survival in rectal cancer patients treated with reirradiation. Methods and Materials: Between February 2001 and February 2005, 50 patients with a history of pelvic radiotherapy were treated with hyperfractionated accelerated radiotherapy for primary (n = 2 ...
Purpose: To prove an expected benefit of concurrent radiochemotherapy (RCT), a two-arm randomized multicentric study was performed. In a subgroup analysis the influence of pretherapeutical hemoglobin level (p-Hb) on survival under locoregional control (SLC) was tested. Patients and Methods: The study included primarily untreated Stage III/IV (International Union Against Cancer [UICC]) ...
We have developed an electronic portal imaging device (EPID) employing a fast scintillator and a high-speed camera. The device is designed to accurately and independently characterize the fluence delivered by a linear accelerator during intensity modulated radiation therapy (IMRT) with either step-and-shoot or dynamic multileaf collimator (MLC) delivery. ...
as a multileaf collimator (MLC) 2 #12;which is attached to the accelerator. Its adjustable heavy-metal leaves act by rotating the accelerator around the patient and coordinating the leaf movements in the MLC so that the radiation delivered conforms to some desirable dose distribution at each gantry (beam) angle. We will assume
The objective of this work is to develop a dosimetric phantom quality assurance (QA) of linear accelerators capable of cone-beam CT (CBCT) image guided and intensity-modulated radiotherapy (IG-IMRT). This phantom is to be used in an integral test to quantify in real-time both the performance of the image guidance and the dose delivery systems in terms of ...
The observation that improved local tumour control also results in increased survival rates, even in a disease such as non-small cell lung cancer (NSCLC), has fuelled the interest in strategies aimed at local tumour eradication. It has been demonstrated that a clear dose-response relationship exists for radiotherapy, i.e. higher doses of radiation lead to increased local tumour control. However, ...
Purpose: To examine the feasibility and acute toxicities of an accelerated, partial breast, intensity-modulated radiotherapy (IMRT) protocol. Methods and Materials: Between February 2004 and August 2005, 55 patients with Stage I breast cancer and initial follow-up were enrolled at four facilities on a HealthONE and Western institutional review ...
Osteoradionecrosis (ORN) is one of the common late adverse effects that follow radiation therapy for head and neck cancers. ORN usually develops on the mandible and less frequently on the maxilla. We present three cases of ORN of the cervical vertebrae, which is rarely reported. Two patients suffered from secondary osteomyelitis after neoadjuvant chemotherapy followed by definitive concurrent ...
The effect of radiation protraction in step-and-shoot IMRT is investigated for treatment plans created with the help of direct aperture optimization. The latter approach can be used during inverse planning for all clinical linear accelerators with conventional MLC. Direct aperture optimization significantly shortens fraction time for ...
The software package "Dosimetry Check" by MathResolutions, LLC, provides an absolute 3D volumetric dose measurement for IMRT QA using the existing Electronic Portal Imaging Device (EPID) mounted on most linear accelerators. This package provides a feedback loop using the patient's treatment planning CT data as the phantom for dose reconstruction. The aim ...
We show that it is possible to translate an intensity modulated radiation therapy (IMRT) treatment plan and deliver it as a single arc. This technique is referred to in this paper as aperture modulation arc therapy (AMAT). During this arc, the MLC leaves do not conform to the projection of the target PTV and the machine output of the accelerator has a ...
The number of intensity modulated radiation therapy (IMRT) procedures is continuously growing worldwide and it is necessary to develop tools for patient specific quality assurance (QA) that avoid using machine time that could be employed in treating additional patients. One way of achieving this goal is to perform a multileaf collimator quality assurance periodically in the ...
As a clinical application of an exciting scientific breakthrough, a compact and cost-efficient proton therapy unit using high-power laser acceleration is being developed at Fox Chase Cancer Center. The significance of this application depends on whether or not it can yield dosimetric superiority over intensity-modulated radiation therapy (IMRT). The goal ...
Purpose: The aim of this study was to compare toxicity/efficacy of conventional radiotherapy using delayed accelerated concomitant boost radiotherapy (CBRT) vs. intensity-modulated radiotherapy (IMRT) in the setting of concurrent chemotherapy (CT) for locally advanced oropharyngeal carcinoma. Methods and Materials: Between September 1998 and June 2004, a ...
Shortening of the overall duration of radiotherapy would reduce the possibility repopulation of tumor during treatment. Most clinical trials of such accelerated radiotherapy have incorporated a split course to improve normal tissue tolerance. Any interruption, however, even for the week-end, may allow repopulation to occur. A scheme of radiotherapy has been used during which ...
Arc-modulated radiation therapy (AMRT) is a novel rotational intensity-modulated radiation therapy (IMRT) technique developed for a clinical linear accelerator that aims to deliver highly conformal radiation treatment using just one arc of gantry rotation. Compared to fixed-gantry IMRT and the multiple-arc intensity-modulated arc ...
A hypofractionation treatment protocol for prostate cancer was initiated in our department in December 2003. The treatment regimen consists of a total dose of 36.25 Gy delivered at 7.25 Gy per fraction over 10 days. We discuss the rationale for such a prostate hypofractionation protocol and the need for frequent prostate imaging during treatment. The CyberKnife (Accuray Inc., Sunnyvale, CA), a ...
Purpose: To date, most intensity-modulated radiation therapy (IMRT) delivery has occurred using linear accelerators (linacs), although helical tomotherapy has become commercially available. To quantify the dosimetric difference, we compared linac-based and helical tomotherapy-based treatment plans for IMRT of the oropharynx. Methods ...
This paper presents early results of a trial of a three-fractions-per-day (TID) regimen that is more convenient to schedule than the Continuous Hyperfractionated Accelerated Radiotherapy (CHART) protocol currently being tested in Europe. The treatment schedule used in the CHART regimen has been modified from 36 fractions of 1.5 Gy TID in 12 days to 72 ...
The purpose of this study was to compare the peripheral doses to various organs from a typical head and neck intensity-modulated radiation therapy (IMRT) treatment delivered by linear accelerator (linac) and helical TomoTherapy. Multiple human CT data sets were used to segment critical structures and organs at risk, fused and adjusted to an anthropomorphic ...
PURPOSE: To compare intensity-modulated arc therapy (IMAT) to noncoplanar intensity-modulated radiation therapy (IMRT) in the treatment of pediatric posterior fossa tumors. METHODS AND MATERIALS: Nine pediatric patients with posterior fossa tumors, mean age 9 years (range, 6-15 years), treated using IMRT were chosen for this comparative planning study ...
We have investigated the feasibility of using a set of multiple MOSFETs in conjunction with the mobile MOSFET wireless dosimetry system, to perform a comprehensive and efficient quality assurance (QA) of IMRT plans. Anatomy specific MOSFET configurations incorporating 5 MOSFETs have been developed for a specially designed IMRT dosimetry phantom. ...
Inter- and intra-leaf transmission and head scatter can play significant roles in intensity modulated radiation therapy (IMRT)-based treatment deliveries. In order to accurately calculate the dose in the IMRT planning process, it is therefore important that the detailed geometry of the multi-leaf collimator (MLC), in addition to other components in the ...
Purpose: Patients with chemotherapy-resistant lymphoma have rapidly progressive disease and a poor prognosis. Local symptoms are treated with radiotherapy (RT) for local control. We have reviewed local control and toxicity in patients treated with hyperfractionated accelerated RT. Methods and Materials: A total of 34 patients received ...
This paper describes the algorithm and examines the performance of an intensity-modulated radiation therapy (IMRT) beam-angle optimization (BAO) system. In this algorithm successive sets of beam angles are selected from a set of predefined directions using a fast simulated annealing (FSA) algorithm. An IMRT beam-profile optimization is performed on each ...
BackgroundFormer meta-analyses have shown a survival benefit for the addition of chemotherapy (CHX) to radiotherapy (RT) and to some extent also for the use of hyperfractionated radiation therapy (HFRT) and accelerated radiation therapy (AFRT) in locally advanced squamous cell carcinoma (SCC) of the head and neck. However, the publication of new studies ...
The purpose of our study was to find a solution for fetal dose reduction during head-and-neck intensity modulated radiation therapy (IMRT) of a pregnant patient. The first step was optimization of the IMRT treatment plan with as few monitor units (MUs) as possible, while maintaining an acceptable dose distribution. The peripheral dose originating from the ...
Purpose: Sparing the hippocampus during cranial irradiation poses important technical challenges with respect to contouring and treatment planning. Herein we report our preliminary experience with whole-brain radiotherapy using hippocampal sparing for patients with brain metastases. Methods and Materials: Five anonymous patients previously treated with whole-brain radiotherapy with hippocampal ...
Direct Machine Parameter Optimization (DMPO) is a leaf segmentation program released as an optional item of the Pinnacle planning system (Philips Radiation Oncology Systems, Milpitas, CA); it is based on the principles of direct aperture optimization where the size, shape, and weight of individual segments are optimized to produce an intensity modulated radiation treatment ...
Background and PurposeThe purpose of this study was to assess plan quality and treatment time achievable with the new VMAT optimization tool implemented in the treatment planning system Oncentra MasterPlan� as compared to IMRT for Elekta SynergyS� linear accelerators.Materials and methodsVMAT was ...
Purpose: Supratentorial primitive neuroectodermal tumors (S-PNET) are rare and have a grim prognosis, frequently taking an aggressive course with local relapse and metastatic spread. We report the results of a mono-institutional therapeutic trial. Methods and Materials: We enrolled 15 consecutive patients to preradiation chemotherapy (CT) consisting of high-dose methotrexate, high-dose etoposide, ...
Purpose: To determine the feasibility of high-dose continuous hyperfractionated accelerated radiotherapy in patients with inoperable non-small-cell lung cancer (NSCLC). Patients and Methods: In a prospective, Phase I/II study, according to the risk for radiation pneumonitis, three risk groups were defined: V{sub 20} <25%, V{sub 20} 25-37%, and V{sub ...
The implementation of intensity-modulated radiation therapy (IMRT) in the clinic necessitates commissioning for all systems involved. This paper describes work carried out for the treatment planning system (Helax-TMS version 6.1) and the treatment delivery equipment (Siemens Primus) available at our center. Particular regard was paid to small monitor units (MUs) and small ...
Results of radiation therapy for malignant tumors have steadily improved, and both radiation biology and radiation physics have contributed to this improvement. As examples of such contribution, radiobiologically-elaborated continuous hyperfractionated accelerated radiotherapy (CHART) has been proven to be superior to conventional radiotherapy against ...
Little has been published so far about the possibility of preserving an uninvolved testicle by surgically transferring it out of the irradiation field. A then 16-year-old boy developed a right paratesticular embryonal rhabdomyosarcoma in 2003. Initial treatment consisted of orchiectomy and chemotherapy. Prior to local radiotherapy, the contralateral testicle was surgically transferred into the ...
The advances in modern radiation therapy with techniques such as intensity-modulated radiation therapy and image-guided radiation therapy (IMRT and IGRT) have been limited almost exclusively to linear accelerators. Investigations of modern Cobalt-60 (Co-60) radiation delivery in the context of IMRT and IGRT have been very sparse, and ...
Tumour proliferation effects can be tentatively quantified in the linear-quadratic (LQ) method by the incorporation of a time-dependent factor, the magnitude of which is related both to the value of alpha in the tumour alpha/beta ratio, and to the tumour doubling time. The method, the principle of which has been suggested by a number of other workers for use in fractionated therapy, is here ...
The task group (TG) for quality assurance of medical accelerators was constituted by the American Association of Physicists in Medicine's Science Council under the direction of the Radiation Therapy Committee and the Quality Assurance and Outcome Improvement Subcommittee. The task group (TG-142) had two main charges. First to update, as needed, recommendations of Table II of ...
Both the planning systems and the form of administering radiotherapy have changed radically since the introduction of 3D planning. At present treatment planning based on computerised axial tomography (CAT) images is standard practice in radiotherapy services. In recent years lineal accelerators for medical use have incorporated technology capable of administering intensity ...
In light of the increasing use of intensity modulated radiation therapy (IMRT) in modern radiotherapy practice, the use of a flattening filter may no longer be necessary. Commissioning data have been measured for a Varian 23EX linear accelerator with 6 and 18 MV photon energies without a flattening filter. Measurements collected for the commissioning of ...
A helical tomotherapy machine combines a straight 6 MV linear accelerator mounted on a ring gantry with CT technology for image-guided intensity-modulated radiation therapy (IMRT) treatment. A fan beam created by the collimator and jaws produces a maximum of 40 x 5 cm(2) field size at the isocenter. The gantry and hence the fan beam rotates at a constant ...
A helical tomotherapy machine combines a straight 6 MV linear accelerator mounted on a ring gantry with CT technology for image-guided intensity-modulated radiation therapy (IMRT) treatment. A fan beam created by the collimator and jaws produces a maximum of 40 � 5 cm2 field size at the isocenter. The gantry and hence the fan beam ...
Purpose: To evaluate the toxicity of pelvic intensity-modulated radiotherapy (IMRT) with hypofractionated simultaneous integrated boost (SIB) to the prostate for patients with intermediate- to high-risk prostate cancer. Methods and Materials: A retrospective toxicity analysis was performed in 30 consecutive patients treated definitively with pelvic ...
For intensity modulated radiation treatment (IMRT) dose reconstruction, multileaf collimator (MLC) log files have been shown applicable for deriving delivered fluence maps. However, MLC log files are dependent on the accuracy of leaf calibration and only available from one linear accelerator manufacturer. This paper presents a proof of feasibility and ...
The purpose of this study was to compare conventional radiotherapy with parotid gland-sparing intensity-modulated radiation therapy (IMRT) using the PARSPORT trial. The validity of such a trial depends on the radiotherapy planning and delivery meeting a defined standard across all centres. At the outset, many of the centres had little or no experience of delivering ...
The Delta4 diode array phantom (Scandidos, Uppsala, Sweden) was evaluated for verification of segmental intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) on an Elekta linear accelerator (Crawley UK). The device was tested for angular sensitivity by irradiating it from 36 different gantry angles, and the responses of ...
Helical tomotherapy uses different planning algorithm and dose delivery method from the linear accelerator (linac)-based intensity-modulated radiotherapy (IMRT). This study compared the dosimetric outcomes between the tomotherapy plans and conventional linac-based IMRT plans in the treatment of nasopharyngeal carcinoma (NPC). Fifteen ...
Radiation therapy treatment planning and delivery capabilities have changed dramatically since the introduction of three-dimensional treatment planning in the 1980s and continue to change in response to the implementation of new technologies. CT simulation and three-dimensional radiation treatment planning systems have become the standard of practice in clinics around the world. Medical ...
The Delta(4) diode array phantom (Scandidos, Uppsala, Sweden) was evaluated for verification of segmental intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) on an Elekta linear accelerator (Crawley UK). The device was tested for angular sensitivity by irradiating it from 36 different gantry angles, and the responses of ...
The rapid development and clinical implementation of external beam radiation treatment technologies continues. The existence of various commercially available technologies for intensity-modulated radiation therapy (IMRT) has stimulated interest in exploring the differential potential advantage one may have compared with another. Two such technologies, Hi-Art Helical ...
This paper describes the initial experience of quality assurance (QA) tests performed on the millennium multi-leaf collimator (mMLC) for clinical implementation of intensity-modulated radiotherapy (IMRT) using sliding window technique. The various QA tests verified the mechanical and dosimetric stability of the mMLC of linear accelerator when operated in ...
Intensity-modulated radiotherapy (IMRT) treatment plan verification by comparison with measured data requires having access to the linear accelerator and is time consuming. In this paper, we propose a method for monitor unit (MU) calculation and plan comparison for step and shoot IMRT based on the Monte Carlo code EGSnrc/BEAMnrc. The ...
Inter- and intra-leaf transmission and head scatter can play significant roles in Intensity Modulated Radiation Therapy (IMRT)-based treatment deliveries. In order to accurately calculate the dose in the IMRT planning process, it is therefore important that the detailed geometry of the multi-leaf collimator (MLC), in addition to other components in the ...
Purpose: To determine the maximum tolerated dose (MTD) of fractionated intensity-modulated radiotherapy (IMRT) with temozolomide (TMZ) in patients with glioblastoma. Methods and Materials: A Phase I clinical trial was performed. Eligible patients had surgically resected or biopsy-proven glioblastoma. Patients started TMZ (75 mg/day) during IMRT and ...
The local tumor control achieved in patients treated in a pilot study of continuous, hyperfractionated, accelerated radiotherapy has been related to the tumor cell kinetics evaluated by in vivo administration of bromodeoxyuridine and flow cytometry. In 42 of 50 patients with advanced squamous cell carcinomas in the head and neck region it was possible to ...
The purpose of this work was to determine whether 2 different types of linear accelerators manufacturers with similar MLC leaf widths deliver equivalent IMRT distributions for head and neck radiotherapy patients. In this study, plans delivered with Siemens linacs were re-optimized with an Elekta linac and vice versa. To test for significance, paired ...
Purpose: To report the results from continuous, hyperfractionated, accelerated radiotherapy (CHART) used as the standard fractionation for radical RT in the management of non-small cell lung cancer (NSCLC) in five United Kingdom centers. Methods and Materials: In 2005, the CHART consortium identified six U.K. centers that had continued to use CHART after ...
Purpose: The aim of this study was twofold: to determine whether the dose-volume metrics are valuable in predicting radiation pneumonitis (RP) in small-cell lung cancer (SCLC) patients treated with accelerated hyperfractionated radiotherapy and chemotherapy (AHFRT + CT); and to clarify how AHFRT influences the risk of RP in comparison to conventional ...
The randomized multicentre trial of continuous hyperfractionated accelerated radiotherapy (CHART) versus conventional radiotherapy in patients with advanced head and neck cancer showed no good evidence of a difference in any of the major clinical outcomes of survival, freedom from metastases, loco-regional control and disease-free survival. Therefore an ...
Purpose: To evaluate, in a Phase II trial conducted August 1998 through January 2001, the efficacy of neoadjuvant chemotherapy followed by chemoradiotherapy and definitive surgery in patients with locally advanced non-small-cell lung cancer (LA-NSCLC), Stages IIIA bulky and selected Stage IIIB. Patients and Methods: Staging of LA-NSCLC included computed tomography of cranium, thorax, and abdomen, ...
Purpose: To evaluate long-term late adverse events and treatment outcome of a randomized, multicenter Phase III trial of continuous, hyperfractionated, accelerated radiotherapy (CHART) compared with conventional radiotherapy (CRT) in 918 patients with advanced squamous cell carcinomas of the head and neck. Methods and Materials: Survival estimates were ...
PURPOSE: Recent clinical trials and meta-analyses have shown that both CHART (continuous hyperfractionated accelerated radiation therapy) and induction chemotherapy offer a survival advantage over conventional radical radiotherapy for patients with inoperable non-small cell-lung cancer (NSCLC). This multicenter randomized controlled trial (INCH) was set up ...
Purpose: To evaluate the feasibility and efficacy of a hyperfractionated accelerated radiotherapy (RT) schedule combined with concomitant chemotherapy (Cx) in patients with locally advanced head-and-neck squamous cell carcinoma. Methods and Materials: Between 2004 and 2007, a total of 90 patients with locoregionally advanced head-and-neck squamous cell ...
Purpose: Anaplastic thyroid carcinoma (ATC) is one of the most aggressive cancers, and the current protocol of hyperfractionated accelerated radiotherapy was initiated to improve survival while limiting toxicities. Methods and Materials: All patients with ATC from 1991 to 2002 were accrued and received megavoltage radiotherapy from the mastoid processes to ...
BACKGROUND: Continuous hyperfractionated accelerated radiotherapy (CHART) counteracts repopulation and may significantly improve outcome of patients with non-small-cell lung cancer (NSCLC). Nevertheless high local failure rates call for radiation dose escalation. We report here the final results of the multicentric CHARTWEL trial (CHART weekend less, ARO ...
Results from the multicentre randomized trial of CHART (continuous, hyperfractionated, accelerated radiotherapy) in non-small-cell lung cancer (NSCLC) showed a significant increase in survival (P=0.004) compared with conventional radiotherapy and a therapeutic benefit relative to late radiation-induced morbidity. However, 60% of patients died because of ...
Radiotherapy is a major treatment modality for head and neck cancer. It is often not possible to exclude the salivary glands from the treatment fields. The unique susceptibility of the serous cells of the salivary glands to irradiation often results in xerostomia with ensuing secondary complications and discomfort to the patients. Recent reports have suggested that continuous ...
The objective of this study was to compare the costs of treatment with continuous hyperfractionated accelerated radiotherapy (CHART) and those of conventional radiotherapy for patients with (1) head and neck cancer and (2) carcinoma of the bronchus. The study was conducted concurrently with two multicentre randomized controlled trials. Data were collected ...
58 patients of advanced head and neck cancer were treated by continuous hyperfractionated accelerated radiotherapy (study group) or conventional radiotherapy (control group). The study group of 29 patients had 26/29 (89%) of patients of stage T3 and T4 with 12/29 (41% 0) > N2 disease. The schedule employed was 1.5 Gy 3 times a day in 36 fractions on 12 ...
Purpose: To analyze a prospective protocol combining surgery, chemotherapy (CT), and hyperfractionated accelerated radiotherapy (RT) in anaplastic thyroid carcinoma. Methods and materials: Thirty anaplastic thyroid carcinoma patients (mean age, 59 years) were treated during 1990-2000. Tumor extended beyond the capsule gland in 26 patients, with tracheal ...
Patients with rectal cancer are at high risk of disease recurrence despite neoadjuvant radiochemotherapy with 5-Fluorouracil (5FU), a regimen that is now widely applied. In order to develop a regimen with increased antitumour activity, we previously established the recommended dose of neoadjuvant CPT-11 (three times weekly 90?mg?m?2) concomitant to ...
Hyperfractionation and hypofractionation combined with acceleration have been investigated in stage I-III NSCLC patients. In stage I tumors, hypofractionated radiation schedules given with highly conformal stereotactic body radiotherapy (SBRT) techniques have been proven safe and effective with local control rates > 85% and meanwhile have been accepted ...
The purpose was to evaluate the feasibility and toxicity of [sup 252]Cf neutron brachytherapy combined with hyperaccelerated chemoradiotherapy for Stage III and IV cervical cancers. Eleven patients with advanced Stage IIIB-IVA cervical cancers were treated with [sup 252]Cf neutron brachytherapy in an up-front schedule followed by cisplatin (CDDP; 50 mg/m[sup 2]) chemotherapy and ...
Radiotherapy is an established modality for women with breast cancer. During the delivery of external beam radiation to the breast, leakage, scattered x-rays from the patient and the linear accelerator also expose healthy tissues and organs outside of the breast, thereby increasing the patient's whole-body dose, which then increases the chance of developing a secondary, ...
The potential conformality advantages of intensity-modulated radiation therapy (IMRT; TomoTherapy Hi Art system) over conventional linear accelerator based therapy was assessed in six consecutive children referred for extracranial radiotherapy. IMRT/tomotherapy was considered advantageous for (i) small abdominal tumours, compared with ...
Purpose: The aim of this study was to evaluate the feasibility of treating the pelvic lymphatic regions during prostate intensity-modulated radiotherapy (IMRT) with respect to our routine acceptance criteria. Methods and Materials: A series of 10 previously treated prostate patients were randomly selected and the pelvic lymphatic regions delineated on the fused magnetic ...
Purpose: The present treatment planning study compared whole breast radiotherapy (WBRT) to accelerated partial breast irradiation (APBI) for different external beam techniques and geometries (e.g., free breathing [FB] and deep inspiration breath hold [DIBH]). Methods and Materials: After approval by our institutional review board, a treatment planning study was performed of 10 ...
Intensity modulated radiotherapy provides improved target coverage and reduced dose to surrounding normal tissues compared with conformal radiotherapy. However, computational quality assurance is more challenging for the complex fluence maps used in IMRT treatments, and direct measurements can be labor-intensive. A Monte Carlo based phase space model has been developed based ...
The very first cornerstone paper on intensity-modulated radiation therapy (IMRT) was published in Physics in Medicine and Biology, and many seminal IMRT works have since appeared in this journal. Today IMRT is a widely used clinical treatment modality in many countries. This contribution to the 50th anniversary issue reviews the ...
... Title : Multiadaptive Plan (MAP) IMRT to Accommodate Independent Movement of the Prostate and Pelvic Lymph Nodes. ...
DTIC Science & Technology
Radiation therapy treatment planning and delivery capabilities have changed dramatically since the introduction of three-dimensional treatment planning and are continuing to change relatively rapidly in response to the implementation of new advanced technologies. Three-dimensional conformal radiation therapy (3DCRT) is now firmly in place as the standard of practice in clinics around the world. ...
Due to leaf travel range limitations of the Varian Dynamic Multileaf Collimator (DMLC) system, an IMRT field width exceeding 14.5 cm is split into two or more adjacent abutting sub-fields. The abutting sub-fields are then delivered as separate treatment fields. The accuracy of the delivery is very sensitive to multileaf positioning accuracy. The uncertainties in leaf and ...
As part of the clinical trial of CHART (continuous hyperfractionated accelerated radiotherapy) a quality assurance programme was included. The technical part of this--which is reported in this paper--is a series of tests designed to check all aspects of treatment planning and delivery. The results of visits to the 13 participating centres--and repeat ...
The prognostic significance of a panel of molecular biomarkers in head and neck squamous cell carcinoma (HNSCC) for first failure site (primary (T), nodal (N) or distant (M)) was analysed in 309 patients randomised to continuous hyperfractionated accelerated radiotherapy (CHART) vs. conventionally fractionated radiotherapy. Multivariate competing risks ...
The aim of this study was to identify possible failure-specific prognostic factors in non-small-cell lung cancer. Clinical outcome was analysed in 549 patients participating in the randomized controlled trial of CHART vs conventional radiotherapy. Local failure and distant failure with or without concurrent local relapse were subjected to a competing risk analysis using an ...
The recent development in linear accelerator control systems, named volumetric-modulated arc therapy (VMAT), has generated significant interest in arc-based intensity-modulated radiation therapy (IMRT). The VMAT delivery technique features simultaneous changes in dose rate, gantry angle and gantry rotation speed as well as multi-leaf collimator (MLC) leaf ...
Absolute dosimetry with ionization chambers of the narrow photon fields used in stereotactic techniques and IMRT beamlets is constrained by lack of electron equilibrium in the radiation field. It is questionable that stopping-power ratio in dosimetry protocols, obtained for broad photon beams and quasi-electron equilibrium conditions, can be used in the dosimetry of narrow ...
Dosimetric parameters of a dedicated stereotactic linear accelerator have been investigated using measurements and Monte Carlo simulations. This linac has a unique built in multileaf collimation (MLC) system with the maximum opening of 16x21 cm{sup 2} and 4 mm leaf width at the isocenter and has successfully been modeled for the first time using the Monte Carlo simulation. The ...
Purpose: The current inverse planning methods for intensity modulated radiation therapy (IMRT) are limited because they are not designed to explore the trade-offs between the competing objectives of tumor and normal tissues. The goal was to develop an efficient multiobjective optimization algorithm that was flexible enough to handle any form of objective function and that ...
Purpose: A physician�s decision regarding an ideal treatment approach (i.e., radiation, surgery, and?or hormonal) for prostate carcinoma is traditionally based on a variety of metrics. One of these metrics is the risk of radiation-induced second primary cancer following radiation treatments. The aim of this study was to investigate the significance of second cancer risks in out-of-field organs ...
Modern radiation therapy techniques such as intensity-modulated radiation therapy (IMRT) and newly-emerging volumetric modulated arc therapy (VMAT) aim to deliver highly conformal radiation dose to the target volume while sparing nearby critical organs as much as possible with the complex motion of multi-leaf collimator (MLC) leaves. Pre-treatment patient specific quality ...
Acute mucositis is the main intensity-limiting toxicity in the management of head and neck (H&N) and digestive track carcinomas with radiotherapy. New radiation modalities (hyperfractionation and/or acceleration) as well as combined modality regimens in this situation induce higher rates of acute toxicity. Hyperfractionation for ...
The authors present a series of 178 patients with Stage III or IV squamous cell carcinoma of the head and neck treated by rapid irradiation using multiple and small fractions per day. An initial group of 91 patients (G1) received a total dose of 72 Gy in 80 sessions and 10 days, according to the following split course schedule: J1 to J5, 36 Gy in 40 sessions, eight daily fractions of .9 Gy ...
The 'four Rs' of radiobiology play an important role in the design of radiation therapy treatment protocol. The purpose of this work is to explore their influence on external beam radiotherapy for fast and slowly proliferating tumors and develop an optimization framework for tumor-biology specific dose-time-fractionation scheme. The linear quadratic model is used to describe ...
IntroductionLung cancer is the leading cause of cancer deaths in both men and women, with 80-90% of cases caused by smoking. Small cell lung cancer accounts for 20% of all cases, and is usually treated with chemotherapy. Adenocarcinoma is the main non-small cell pathology, and is treated initially with surgery.Methods and outcomesWe conducted a systematic review and aimed to answer the following ...
The role of multimodality management in locally advanced non-small cell lung cancer (NSCLC) continues to evolve and is a subject of ongoing clinical research. Induction chemotherapy followed by surgical resection with or without thoracic radiotherapy has proved superior to surgical resection alone in patients with ipsilateral mediastinal (N2) disease. Whether surgery alone still plays a role in ...
Purpose: To measure the photon and neutron out-of-treatment-field dose equivalents to various organs from different treatment strategies (conventional vs. intensity-modulated radiation therapy [IMRT]) at different treatment energies and delivered by different accelerators. Methods and Materials: Independent measurements were made of the photon and neutron ...
The Anisotropic Analytical Algorithm (AAA) is a new pencil beam convolution/superposition algorithm proposed by Varian for photon dose calculations. The configuration of AAA depends on linear accelerator design and specifications. The purpose of this study was to investigate the accuracy of AAA for an Elekta SL25 linear accelerator for small fields and ...
Skin toxicity has been reported for IMRT of head and neck cancer. The purpose of this study was to investigate the dose in the build-up region delivered by a 6 MV treatment plan for which important skin toxicity was observed. We also investigated if the different designs of the treatment head of an Elekta and a Varian linear accelerator, especially the ...
Determination of shielding requirements for medical linear accelerators has been greatly facilitated by the publication of the National Council on Radiation Protection and Measurements (NCRP) latest guidelines on this subject in NCRP Report No. 151. In the present report the authors review their own recent experience with patient treatments on conventional dual energy linear ...
The development of advanced intensity modulated radiation therapy (IMRT) techniques has led to significant improvements in our ability to treat complicated target volumes with minimal collateral damage to the surrounding healthy tissue. These techniques however, come at the cost of increased complexity; which translates into increased sensitivity of the optimized treatment ...
Intensity modulated arc therapy (IMAT) is a radiation therapy technique whereby the shape of the cone beam of radiation changes as it rotates around the patient. This is in contrast to other more commonly delivered forms of advanced radiation therapy, Intensity Modulated Radiation Therapy (IMRT) or helical tomotherapy. IMRT is a radiation technique where a ...
In this paper, we described and characterized a novel biplanar diode array, and demonstrated its applicability to dosimetric QA of the step-and-shoot IMRT. It is the first commercially available device of its kind specifically designed for measurements at varying gantry angles. The detector consists of a cylindrical PMMA phantom with two orthogonal detector boards. There are a ...
Intensity-modulated radiation therapy (IMRT) is a 3D conformal radiation therapy technique that utilizes either a multileaf intensity-modulating collimator (MIMiC used with the NOMOS Peacock system) or a multileaf collimator (MLC) on a conventional linear accelerator for beam intensity modulation to afford increased conformity in dose distributions. Due to ...
This work introduces an EGSnrc-based Monte Carlo (MC) beamlet does distribution matrix into a direct aperture optimization (DAO) algorithm for IMRT inverse planning. The technique is referred to as Monte Carlo-direct aperture optimization (MC-DAO). The goal is to assess if the combination of accurate Monte Carlo tissue inhomogeneity modeling and DAO inverse planning will ...
The objective of this paper is to present our experience in the commissioning and quality assurance (QA) for intensity modulated radiotherapy (IMRT) using dynamic multileaf collimator (dMLC), sliding window technique. Using Varian equipment solution, the connectivity and operation between all IMRT chain components was checked. Then the following test were ...
The authors have developed a quality factor (QF) to compare gamma knife radiosurgery, linear accelerator radiosurgery, and intensity-modulated radiation therapy (IMRT) dosimetry. This QF relates the percentage of target covered (PTC) by the prescription radiation isodose, target volume (V(T)), and enclosed tissue volume, which receives greater than a ...
Purpose: To investigate the use of topotherapy for accelerated partial breast irradiation through field-design optimization and dosimetric comparison to linear accelerator-based three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiation therapy (IMRT). Methods and Materials: Hypothetical 3-cm lumpectomy sites ...
The integration of onboard kV imaging together with a MV electronic portal imaging device (EPID) on linear accelerators (LINAC) can provide an easy to implement real-time 3D organ position monitoring solution for treatment delivery. Currently, real-time MV-kV tracking has only been demonstrated by simultaneous imagining by both MV and kV imaging devices. However, modalities ...
Objectives: Volumetric-modulated arc therapy (VMAT) is becoming an increasingly utilised modality for treating a variety of anatomical sites. However, the efficacy of single-arc VMAT to treat prostate cancer suspicious for extraprostatic extension was heretofore unknown. In this work, we report our institutional experience with single-arc VMAT and fixed-beam intensity-modulated radiation therapy ...
The technology of online mega-voltage cone-beam (CB) computed tomography (MV-CBCT) imaging is currently used in many institutions to generate a 3D anatomical dataset of a patient in treatment position. It utilizes an accelerator therapy beam, delivered with 200 deg. gantry rotation, and captured by an electronic portal imager to account for organ motion and setup variations. ...
Amorphous silicon (a-Si) electronic portal imaging devices (EPIDs) continue to be investigated as treatment verification tools, with a particular focus on intensity modulated radiation therapy (IMRT). This verification could be accomplished through a comparison of measured portal images to predicted portal dose images. A general fluence determination tailored to portal dose ...
There is growing concern about radiation-induced second cancers associated with radiation treatments. Particular attention has been focused on the risk to patients treated with intensity-modulated radiation therapy (IMRT) due primarily to increased monitor units. To address this concern we have combined a detailed medical linear accelerator model of the ...
When delivering intensity-modulated radiation therapy (IMRT) using the volumetric modulated arc therapy (VMAT) technique on an Elekta accelerator equipped with the Elekta Beam Modulator multileaf collimator (MLC), the orientation of the MLC, relative to the accelerator head, is generally fixed during the delivery. However, it has the ...
A combined system of a 6 MV linear accelerator and a 1.5 T MRI scanner is currently being developed. In this system, the patient will be irradiated in the presence of a 1.5 T magnetic field. This causes a strong dose increase at tissue-air interfaces. Around air cavities in the patient, these effects may become problematic. Homogeneous dose distributions can be obtained around ...
In this study we investigate the characteristics of a rounded leaf end multileaf collimator (MLC) that is used for delivering intensity-modulated radiotherapy (IMRT) with a Varian linear accelerator. The rounded leaf end MLC design results in an offset between the radiation field edge (the physical leaf position) and the light field (the geometric leaf ...
Purpose: Whole breast irradiation (WBI) is the standard of care for patients with early-stage breast cancer who opt for breast conservation. After a randomized trial demonstrated equivalent cosmesis and disease control with accelerated WBI (AWBI), our institution began to offer AWBI to appropriate patients. The aim of this study was to examine our unique experience with AWBI ...
The simplicity of cobalt units gives them the advantage of reduced maintenance, running costs and downtime when compared with linear accelerators. However, treatments carried out on such units are typically limited to simple techniques. This study has explored the use of cobalt beams for conformal and intensity-modulated radiotherapy (IMRT). Six patients, ...
Linear accelerators from the same vendor in a radiation therapy center are usually beam-matched following Vendor's acceptance criteria. This protocol is limited to check the difference at particular points on the ionization curve for depth dose or beam profiles. This article describes different tests done after commissioning to evaluate the level of agreement between matched ...
The most efficacious treatment method for head and neck cancer is not yet defined. However, there have been some improvements made in the radiotherapy of head and neck cancer that are encouraging. Both hyperfractionated radiation therapy and accelerated radiation therapy have improved the local control rates in numerous primary sites, and the results of ...
While radiotherapy is proceeding, tumour cells may proliferate. The use of small individual doses reduces late morbidity. Continuous hyperfractionated accelerated radiation therapy (CHART), which reduces overall treatment from 6-7 weeks to 12 days and gives 36 small fractions, has now been tested in multicentre randomised controlled clinical trials. The ...
Radiotherapy is the usual mode of treatment for unresectable head and neck cancer. To improve cure rates, extend survival, and reduce morbidity, we use accelerated hyperfractionation radiotherapy and an adjuvant drug to inhibit prostaglandin synthesis. In this study, 19 patients received 300 rad/day of radiotherapy in two equally divided doses to a total ...
Five hundred and fifty thousand new head and neck cancer cases are diagnosed each year worldwide. They are mostly locally advanced squamous cell carcinoma with a poor prognosis in terms of locoregional and distant failure. A major challenge for patients with locally advanced squamous cell carcinoma is to achieve a high cure rate while preserving functions. Treatment strategies are designed ...
The changes in serum amylase that occur when radiotherapy is given in the treatment of head and neck cancer has been studied in 41 patients, 29 treated by CHART and 12 by conventionally fractionated radiotherapy. The peak rise in serum amylase following the start of treatment is seen earlier and is greater in the patients receiving continuous hyperfractionated ...
The late radiation change observed in 15 patients treated for carcinoma of oral cavity or oropharynx using continuous hyperfractionated accelerated radiotherapy (CHART) was compared to that seen in 15 similar patients treated with conventional radiotherapy. The average follow up was, 31 and 33 months, respectively. A new dictionary for the recording of ...
The use of megavoltage electron beams often poses a clinical challenge in that the planning target volume (PTV) is anterior to other radiosensitive structures and has variable depth. To ensure that skin as well as the deepest extent of the PTV receives the prescribed dose entails prescribing to a point beyond the depth of peak dose for a single electron energy. This causes dose inhomogeneities and ...
Electronic portal imaging devices (EPIDs) were introduced originally for patient position verification. The idea of using EPIDs for dosimetry was realised in the 1980s. Little was published on the topic until the mid 1990's, when the interest in EPIDs for dosimetry increased rapidly and continues to grow. The increasing research on EPID dosimetry coincided with the introduction of intensity ...
Purpose: To analyze the toxicity profile of an intensified definitive chemoradiotherapy (CRT) schedule in patients with locally advanced non-small-cell lung cancer (Stage IIIA N2/selected IIIB) treated within a prospective multicenter trial. Patients and Methods: After mediastinoscopy and routine staging procedures, three cycles of induction chemotherapy (cisplatin 50 mg/m{sup 2}, Days 1 and 8; ...
This pilot study investigated the feasibility, toxicity and effect of continuous, hyperfractionated, accelerated radiotherapy (CHART) in 19 patients with adenocarcinoma of the rectum who were treated at Mount Vernon Hospital between April 1992 and April 1994. A total dose of 54 Gy was given in 36 fractions over 12 consecutive days; three fractions of 1.5 ...
Kilovoltage imaging systems on linear accelerators are used for patient localization in many clinics. The purpose of this work is to assess on-board imaging (OBI) detection of systematic setup errors and in particular, the dosimetric consequences of undetected head roll in head-and-neck intensity modulated radiation therapy (IMRT) plans when using these ...
For the step-and-shoot intensity-modulated radiation therapy (IMRT) technique, the combination of high dose rate, multiple beam segments and low dose per segment can lead to significant differences between the planned dose and the dose delivered to the patient. In this technique, a dose delivery inaccuracy known as the 'overshoot' effect is caused by the dose servo control ...
Purpose: To analyze the outcome in all oropharynx cancer patients treated at University of Wisconsin during 1995-2005 and highlight the methodologic challenge in comparing outcome after intensity-modulated radiotherapy (IMRT) with that of historical controls. Methods and Materials: Outcomes were compared in 195 oropharynx cancer patients after definitive radiotherapy with ...
IMRT has become one of the main tools for prostate cancer treatment. Current IMRT inverse planning is mainly performed using dose-based objective functions, which oversimplify the problem and ignore the useful biological properties of target and normal ti...
National Technical Information Service (NTIS)
Mathematical modeling was used to reach qualitative conclusions concerning the relative rate of local tumor control that might be achieved by using accelerated fractionation to treat only the patients with the most rapidly growing tumors, compared with the control rates that could be expected from either conventional or accelerated radiotherapy alone. The ...
From October 1990 to March 1994, 90 patients entered a prospectively randomised trial in head and neck cancer. All patients had verified squamous cell carcinoma and were referred for primary radiation therapy. Tumours originated in the oral cavity in 25, oropharynx in 37, larynx in 15 and hypopharynx in 13 cases. Patients' stages were predominantely T3 and T4 (71/90) and had lymph node metastases ...
A case report of an angiosarcoma treated definitively with hyperfractionated irradiation is presented. Radial and ulnar aspects of the proximal forearm, wrist, and digits were diffusely involved on angiography. Hyperfractionated irradiation totaling 7,440 cGy was delivered to the entire circumference of the hand, forearm, and distal 5 cm of the arm; a ...
... were scheduled to undergo HDR brachytherapy and IMRT, as currently being performed in a Phase I/II Trial at VCU MCC, however, increased ...
... HDR/IMRT in Prostate Cancer: Combined Molecular Targeting ... POSITRON EMISSION TOMOGRAPHY, OPTIMIZATION, THERAPY, TARGETING. ...
... Page 17. 17 INTRODUCTION Advances in radiotherapy have made intensity-modulated radiation therapy (IMRT) an effective ...
... to protect his only abdomen kidney This approach ... therapy (IMRT) prevent additional toxicity of treating ... compared to treatment of the prostate only? ...
In vivo dosimetry has a well established role in the quality assurance of 2D radiotherapy and 3D conformal radiotherapy. The role of in vivo dosimetry for IMRT is not as well established. IMRT introduces a range of technical issues that complicate in vivo dosimetry. The first decade or so of IMRT implementation has largely relied upon ...
Previous studies have demonstrated that simple intensity-modulated radiotherapy (IMRT) plans can be produced with a series of rectangular segments formed by conventional jaws. This study investigates whether complex IMRT plans for head and neck cancer can be delivered with the conventional jaws efficiently. Six nasopharyngeal cancer patients, previously ...
The application of multiple portal image acquisition to collimator position verification during dynamic multileaf collimation (DMLC) using a commercial camera-based electronic portal imaging device (EPID) (TheraviewTM, Cablon Medical BV, Leusden, The Netherlands) mounted on an Elekta SL15i accelerator (Elekta Oncology Systems, Crawley, UK) is described. This is achieved using ...
A new accurate Monte Carlo code for IMRT dose computations, MCDE (Monte Carlo dose engine), is introduced. MCDE is based on BEAMnrc/DOSXYZnrc and consequently the accurate EGSnrc electron transport. DOSXYZnrc is reprogrammed as a component module for BEAMnrc. In this way both codes are interconnected elegantly, while maintaining the BEAM structure and only minimal changes to ...
