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Sample records for auto-contoured target volume

  1. PET-CT-Based Auto-Contouring in Non-Small-Cell Lung Cancer Correlates With Pathology and Reduces Interobserver Variability in the Delineation of the Primary Tumor and Involved Nodal Volumes

    SciTech Connect

    Baardwijk, Angela van . E-mail: angela.vanbaardwijk@maastro.nl; Bosmans, Geert; Boersma, Liesbeth; Buijsen, Jeroen; Wanders, Stofferinus; Hochstenbag, Monique; Suylen, Robert-Jan van; Dekker, Andre; Dehing-Oberije, Cary; Houben, Ruud; Bentzen, Soren M.; Kroonenburgh, Marinus van; Lambin, Philippe; Ruysscher, Dirk de

    2007-07-01

    Purpose: To compare source-to-background ratio (SBR)-based PET-CT auto-delineation with pathology in non-small-cell lung cancer (NSCLC) and to investigate whether auto-delineation reduces the interobserver variability compared with manual PET-CT-based gross tumor volume (GTV) delineation. Methods and Materials: Source-to-background ratio-based auto-delineation was compared with macroscopic tumor dimensions to assess its validity in 23 tumors. Thereafter, GTVs were delineated manually on 33 PET-CT scans by five observers for the primary tumor (GTV-1) and the involved lymph nodes (GTV-2). The delineation was repeated after 6 months with the auto-contour provided. This contour was edited by the observers. For comparison, the concordance index (CI) was calculated, defined as the ratio of intersection and the union of two volumes (A intersection B)/(A union B). Results: The maximal tumor diameter of the SBR-based auto-contour correlated strongly with the macroscopic diameter of primary tumors (correlation coefficient = 0.90) and was shown to be accurate for involved lymph nodes (sensitivity 67%, specificity 95%). The median auto-contour-based target volumes were smaller than those defined by manual delineation for GTV-1 (31.8 and 34.6 cm{sup 3}, respectively; p = 0.001) and GTV-2 (16.3 and 21.8 cm{sup 3}, respectively; p 0.02). The auto-contour-based method showed higher CIs than the manual method for GTV-1 (0.74 and 0.70 cm{sup 3}, respectively; p < 0.001) and GTV-2 (0.60 and 0.51 cm{sup 3}, respectively; p = 0.11). Conclusion: Source-to-background ratio-based auto-delineation showed a good correlation with pathology, decreased the delineated volumes of the GTVs, and reduced the interobserver variability. Auto-contouring may further improve the quality of target delineation in NSCLC patients.

  2. Validation of a Magnetic Resonance Imaging-based Auto-contouring Software Tool for Gross Tumour Delineation in Head and Neck Cancer Radiotherapy Planning.

    PubMed

    Doshi, T; Wilson, C; Paterson, C; Lamb, C; James, A; MacKenzie, K; Soraghan, J; Petropoulakis, L; Di Caterina, G; Grose, D

    2017-01-01

    To carry out statistical validation of a newly developed magnetic resonance imaging (MRI) auto-contouring software tool for gross tumour volume (GTV) delineation in head and neck tumours to assist in radiotherapy planning. Axial MRI baseline scans were obtained for 10 oropharyngeal and laryngeal cancer patients. GTV was present on 102 axial slices and auto-contoured using the modified fuzzy c-means clustering integrated with the level set method (FCLSM). Peer-reviewed (C-gold) manual contours were used as the reference standard to validate auto-contoured GTVs (C-auto) and mean manual contours (C-manual) from two expert clinicians (C1 and C2). Multiple geometric metrics, including the Dice similarity coefficient (DSC), were used for quantitative validation. A DSC≥0.7 was deemed acceptable. Inter- and intra-variabilities among the manual contours were also validated. The two-dimensional contours were then reconstructed in three dimensions for GTV volume calculation, comparison and three-dimensional visualisation. The mean DSC between C-gold and C-auto was 0.79. The mean DSC between C-gold and C-manual was 0.79 and that between C1 and C2 was 0.80. The average time for GTV auto-contouring per patient was 8 min (range 6-13 min; mean 45 s per axial slice) compared with 15 min (range 6-23 min; mean 88 s per axial slice) for C1. The average volume concordance between C-gold and C-auto volumes was 86.51% compared with 74.16% between C-gold and C-manual. The average volume concordance between C1 and C2 volumes was 86.82%. This newly designed MRI-based auto-contouring software tool shows initial acceptable results in GTV delineation of oropharyngeal and laryngeal tumours using FCLSM. This auto-contouring software tool may help reduce inter- and intra-variability and can assist clinical oncologists with time-consuming, complex radiotherapy planning. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  3. SU-C-BRA-05: Delineating High-Dose Clinical Target Volumes for Head and Neck Tumors Using Machine Learning Algorithms

    SciTech Connect

    Cardenas, C; Wong, A; Mohamed, A; Fuller, C; Yang, J; Court, L; Aristophanous, M; Rao, A

    2016-06-15

    Purpose: To develop and test population-based machine learning algorithms for delineating high-dose clinical target volumes (CTVs) in H&N tumors. Automating and standardizing the contouring of CTVs can reduce both physician contouring time and inter-physician variability, which is one of the largest sources of uncertainty in H&N radiotherapy. Methods: Twenty-five node-negative patients treated with definitive radiotherapy were selected (6 right base of tongue, 11 left and 9 right tonsil). All patients had GTV and CTVs manually contoured by an experienced radiation oncologist prior to treatment. This contouring process, which is driven by anatomical, pathological, and patient specific information, typically results in non-uniform margin expansions about the GTV. Therefore, we tested two methods to delineate high-dose CTV given a manually-contoured GTV: (1) regression-support vector machines(SVM) and (2) classification-SVM. These models were trained and tested on each patient group using leave-one-out cross-validation. The volume difference(VD) and Dice similarity coefficient(DSC) between the manual and auto-contoured CTV were calculated to evaluate the results. Distances from GTV-to-CTV were computed about each patient’s GTV and these distances, in addition to distances from GTV to surrounding anatomy in the expansion direction, were utilized in the regression-SVM method. The classification-SVM method used categorical voxel-information (GTV, selected anatomical structures, else) from a 3×3×3cm3 ROI centered about the voxel to classify voxels as CTV. Results: Volumes for the auto-contoured CTVs ranged from 17.1 to 149.1cc and 17.4 to 151.9cc; the average(range) VD between manual and auto-contoured CTV were 0.93 (0.48–1.59) and 1.16(0.48–1.97); while average(range) DSC values were 0.75(0.59–0.88) and 0.74(0.59–0.81) for the regression-SVM and classification-SVM methods, respectively. Conclusion: We developed two novel machine learning methods to delineate

  4. WE-G-BRD-07: Automated MR Image Standardization and Auto-Contouring Strategy for MRI-Based Adaptive Brachytherapy for Cervix Cancer

    SciTech Connect

    Saleh, H Al; Erickson, B; Paulson, E

    2015-06-15

    Purpose: MRI-based adaptive brachytherapy (ABT) is an emerging treatment modality for patients with gynecological tumors. However, MR image intensity non-uniformities (IINU) can vary from fraction to fraction, complicating image interpretation and auto-contouring accuracy. We demonstrate here an automated MR image standardization and auto-contouring strategy for MRI-based ABT of cervix cancer. Methods: MR image standardization consisted of: 1) IINU correction using the MNI N3 algorithm, 2) noise filtering using anisotropic diffusion, and 3) signal intensity normalization using the volumetric median. This post-processing chain was implemented as a series of custom Matlab and Java extensions in MIM (v6.4.5, MIM Software) and was applied to 3D T2 SPACE images of six patients undergoing MRI-based ABT at 3T. Coefficients of variation (CV=σ/µ) were calculated for both original and standardized images and compared using Mann-Whitney tests. Patient-specific cumulative MR atlases of bladder, rectum, and sigmoid contours were constructed throughout ABT, using original and standardized MR images from all previous ABT fractions. Auto-contouring was performed in MIM two ways: 1) best-match of one atlas image to the daily MR image, 2) multi-match of all previous fraction atlas images to the daily MR image. Dice’s Similarity Coefficients (DSCs) were calculated for auto-generated contours relative to reference contours for both original and standardized MR images and compared using Mann-Whitney tests. Results: Significant improvements in CV were detected following MR image standardization (p=0.0043), demonstrating an improvement in MR image uniformity. DSCs consistently increased for auto-contoured bladder, rectum, and sigmoid following MR image standardization, with the highest DSCs detected when the combination of MR image standardization and multi-match cumulative atlas-based auto-contouring was utilized. Conclusion: MR image standardization significantly improves MR image

  5. The effects of target motion in kV-CBCT imaging.

    PubMed

    Padmanaban, Sriram; Boopathy, Raghavendiran; Kunjithapatham, Bhuvana; Sukumar, Prabakar; Nagarajan, Vivekanandan

    2010-01-01

    To study the impact of target motion in kV-CBCT imaging. To simulate the respiratory movement, dynamic phantom was programmed to move in three-dimension with a period of four seconds and of two different amplitudes (PA1 and PA2). The targets of well defined geometries (cylinder, sphere, solid triangle, U-shaped and dumbbell) were made using wax. The static targets were CT imaged (reference image). Using CBCT, the targets in static and dynamic modes were imaged under full-fan beam. The line profiles along cranio-caudal direction, influence of target's initial moving phase and volume estimation using auto-contouring tool were used to analyze the effects of target motion on CBCT imaging. Comparing the line profiles of targets in CBCT with CT, the length of average HU spread was reduced by 42.54±1.85%, except the cylindrical target which is by 19.35% for PA1. The percentage difference in reconstructed volume of static targets imaged using CBCT and CT (HU WW -500 to 0) ranges from -1.32% to -5.94%. The volume losses for targets imaged in dynamic mode PA1 ranges from 14.35% to 30.95% and for PA2 it was 21.29% to 43.80%. The solid triangle and cylindrical targets suffered the maximum and minimum volume losses respectively. Non-gated CBCT imaging of the moving targets encounters significant loss of volumetric information, due to scatter artifacts. These may result in a systematic error in re-contouring when CBCT images are used for the re-planning work.

  6. Combined Recipe for Clinical Target Volume and Planning Target Volume Margins

    SciTech Connect

    Stroom, Joep; Gilhuijs, Kenneth; Vieira, Sandra; Chen, Wei; Salguero, Javier; Moser, Elizabeth; Sonke, Jan-Jakob

    2014-03-01

    Purpose: To develop a combined recipe for clinical target volume (CTV) and planning target volume (PTV) margins. Methods and Materials: A widely accepted PTV margin recipe is M{sub geo} = aΣ{sub geo} + bσ{sub geo}, with Σ{sub geo} and σ{sub geo} standard deviations (SDs) representing systematic and random geometric uncertainties, respectively. On the basis of histopathology data of breast and lung tumors, we suggest describing the distribution of microscopic islets around the gross tumor volume (GTV) by a half-Gaussian with SD Σ{sub micro}, yielding as possible CTV margin recipe: M{sub micro} = ƒ(N{sub i}) × Σ{sub micro}, with N{sub i} the average number of microscopic islets per patient. To determine ƒ(N{sub i}), a computer model was developed that simulated radiation therapy of a spherical GTV with isotropic distribution of microscopic disease in a large group of virtual patients. The minimal margin that yielded D{sub min} <95% in maximally 10% of patients was calculated for various Σ{sub micro} and N{sub i}. Because Σ{sub micro} is independent of Σ{sub geo}, we propose they should be added quadratically, yielding for a combined GTV-to-PTV margin recipe: M{sub GTV-PTV} = √([aΣ{sub geo}]{sup 2} + [ƒ(N{sub i})Σ{sub micro}]{sup 2}) + bσ{sub geo}. This was validated by the computer model through numerous simultaneous simulations of microscopic and geometric uncertainties. Results: The margin factor ƒ(N{sub i}) in a relevant range of Σ{sub micro} and N{sub i} can be given by: ƒ(N{sub i}) = 1.4 + 0.8log(N{sub i}). Filling in the other factors found in our simulations (a = 2.1 and b = 0.8) yields for the combined recipe: M{sub GTV-PTV} = √((2.1Σ{sub geo}){sup 2} + ([1.4 + 0.8log(N{sub i})] × Σ{sub micro}){sup 2}) + 0.8σ{sub geo}. The average margin difference between the simultaneous simulations and the above recipe was 0.2 ± 0.8 mm (1 SD). Calculating M{sub geo} and M{sub micro} separately and adding them linearly overestimated PTVs by on

  7. The effects of target motion in kV-CBCT imaging

    PubMed Central

    Padmanaban, Sriram; Boopathy, Raghavendiran; Kunjithapatham, Bhuvana; Sukumar, Prabakar; Nagarajan, Vivekanandan

    2010-01-01

    Summary Background: To study the impact of target motion in kV-CBCT imaging. Material/Methods: To simulate the respiratory movement, dynamic phantom was programmed to move in three-dimension with a period of four seconds and of two different amplitudes (PA1 and PA2). The targets of well defined geometries (cylinder, sphere, solid triangle, U-shaped and dumbbell) were made using wax. The static targets were CT imaged (reference image). Using CBCT, the targets in static and dynamic modes were imaged under full-fan beam. The line profiles along cranio-caudal direction, influence of target’s initial moving phase and volume estimation using auto-contouring tool were used to analyze the effects of target motion on CBCT imaging. Results: Comparing the line profiles of targets in CBCT with CT, the length of average HU spread was reduced by 42.54±1.85%, except the cylindrical target which is by 19.35% for PA1. The percentage difference in reconstructed volume of static targets imaged using CBCT and CT (HU WW −500 to 0) ranges from −1.32% to −5.94%. The volume losses for targets imaged in dynamic mode PA1 ranges from 14.35% to 30.95% and for PA2 it was 21.29% to 43.80%. The solid triangle and cylindrical targets suffered the maximum and minimum volume losses respectively. Conclusions: Non-gated CBCT imaging of the moving targets encounters significant loss of volumetric information, due to scatter artifacts. These may result in a systematic error in re-contouring when CBCT images are used for the re-planning work. PMID:22802763

  8. [Clinical to planning target volume margins in prostate cancer radiotherapy].

    PubMed

    Ramiandrisoa, F; Duvergé, L; Castelli, J; Nguyen, T D; Servagi-Vernat, S; de Crevoisier, R

    2016-10-01

    The knowledge of inter- and intrafraction motion and deformations of the intrapelvic target volumes (prostate, seminal vesicles, prostatectomy bed and lymph nodes) as well as the main organs at risk (bladder and rectum) allow to define rational clinical to planning target volume margins, depending on the different radiotherapy techniques and their uncertainties. In case of image-guided radiotherapy, prostate margins and seminal vesicles margins can be between 5 and 10mm. The margins around the prostatectomy bed vary from 10 to 15mm and those around the lymph node clinical target volume between 7 and 10mm. Stereotactic body radiotherapy allows lower margins, which are 3 to 5mm around the prostate. Image-guided and stereotactic body radiotherapy with adequate margins allow finally moderate or extreme hypofractionation.

  9. [Radiotherapy for cervix carcinomas: clinical target volume delineation].

    PubMed

    Gnep, K; Mazeron, R

    2013-10-01

    Concurrent chemoradiation followed by brachytherapy is currently the standard treatment for locally advanced cervix carcinomas. Modern radiation techniques require planning based on 3D images, and therefore an accurate delineation of target volumes. The clinical target volume (CTV) used for the different phases of treatment are now well defined, but are not always easy to delineate on a CT scan which is currently the standard examination for simulation in radiotherapy. MRI and PET-CT are routinely performed at diagnosis, and can be used to improve the accuracy of the delineation. The objective of this review is to describe the definitions and recommendations of CTV in the treatment of cervical cancer.

  10. Interobserver Variation of Clinical Target Volume Delineation in Gastric Cancer

    SciTech Connect

    Jansen, Edwin; Verheij, Marcel

    2010-07-15

    Purpose: To evaluate interobserver variability in clinical target volume (CTV) delineation in gastric cancer performed with the help of a delineation guide. Patients and Methods: Ten radiotherapy centers that participate in the CRITICS Phase III trial were provided with a delineation atlas, preoperative CT scans, a postoperative planning CT scan, and clinical information for a gastric cancer case and were asked to construct a CTV and create a dosimetric plan according to departmental policy. Results: The volumes of the CTVs and planning target volumes (PTVs) differed greatly, with a mean (SD) CTV volume of 392 (176) cm{sup 3} (range, 240-821cm{sup 3}) and PTV volume of 915 (312) cm{sup 3} (range, 634-1677cm{sup 3}). The overlapping volume was 376cm{sup 3} for the CTV and 890cm{sup 3} for the PTV. The greatest differences in the CTV were seen at the cranial and caudal parts. After planning, dose coverage of the overlapping PTV volume showed less variability than the CTV. Conclusion: In this series of 10 plans, variability of the CTV in postoperative chemoradiotherapy for gastric cancer is large. Strict and clear delineation guidelines should be provided, especially in Phase III multicenter studies. Adaptations of these guidelines should be evaluated in clinical studies.

  11. Diffusion tensor imaging for target volume definition in glioblastoma multiforme.

    PubMed

    Berberat, Jatta; McNamara, Jane; Remonda, Luca; Bodis, Stephan; Rogers, Susanne

    2014-10-01

    Diffusion tensor imaging (DTI) is an MR-based technique that may better detect the peritumoural region than MRI. Our aim was to explore the feasibility of using DTI for target volume delineation in glioblastoma patients. MR tensor tracts and maps of the isotropic (p) and anisotropic (q) components of water diffusion were coregistered with CT in 13 glioblastoma patients. An in-house image processing program was used to analyse water diffusion in each voxel of interest in the region of the tumour. Tumour infiltration was mapped according to validated criteria and contralateral normal brain was used as an internal control. A clinical target volume (CTV) was generated based on the T1-weighted image obtained using contrast agent (T1Gd), tractography and the infiltration map. This was compared to a conventional T2-weighted CTV (T2-w CTV). Definition of a diffusion-based CTV that included the adjacent white matter tracts proved highly feasible. A statistically significant difference was detected between the DTI-CTV and T2-w CTV volumes (p < 0.005, t = 3.480). As the DTI-CTVs were smaller than the T2-w CTVs (tumour plus peritumoural oedema), the pq maps were not simply detecting oedema. Compared to the clinical planning target volume (PTV), the DTI-PTV showed a trend towards volume reduction. These diffusion-based volumes were smaller than conventional volumes, yet still included sites of tumour recurrence. Extending the CTV along the abnormal tensor tracts in order to preserve coverage of the likely routes of dissemination, whilst sparing uninvolved brain, is a rational approach to individualising radiotherapy planning for glioblastoma patients.

  12. Volume-targeted ventilation and arterial carbon dioxide in neonates.

    PubMed

    Dawson, Catherine; Davies, Mark William

    2005-01-01

    To review the arterial carbon dioxide tensions (PaCO(2)) in newborn infants ventilated using synchronized intermittent mandatory ventilation (SIMV) in volume guarantee mode (using the Dräger Babylog 8000+) with a unit policy targeting tidal volumes of approximately 4 mL/kg. Data on ventilator settings and arterial PaCO(2) levels were collected on all arterial blood gases (ABG; n = 288) from 50 neonates (<33 weeks gestational age) ventilated using the Dräger Babylog 8000+ ventilator (Dräger Medizintechnik GmbH, Lübeck, Germany) in SIMV plus volume guarantee mode. Data were analysed for all blood gases done on the entire cohort in the first 48 h of life and a subanalysis was done on the first gas for each infant (n = 38) ventilated using volume guarantee from admission to the nursery. The number of ABG showing severe hypocapnoea (PaCO(2) < 25 mmHg) and/or severe hypercapnoea (PaCO(2) > 65 mmHg) were determined. The mean (SD) PaCO(2) during the first 48 h was 46.6 (9.0) mmHg. The mean (SD) PaCO(2) on the first blood gas of those infants commenced on volume guarantee from admission was 45.1 (12.5) mmHg. Severe hypo- or hypercapnoea occurred in 8% of infants at the time of their first blood gas measurement, and in <4% of blood gas measurements in the first 48 h. Infants ventilated with volume guarantee ventilation targeting approximately 4 mL/kg (range: 2.9-5.1) have acceptable PaCO(2) levels at the first blood gas measurement and during the first 48 h of life; and avoid severe hypo- or hypercapnoea over 90% of the time.

  13. A method to individualize adaptive planning target volumes for deformable targets

    NASA Astrophysics Data System (ADS)

    Wright, Pauliina; Redpath, Anthony Thomas; Høyer, Morten; Muren, Ludvig Paul

    2009-12-01

    We have investigated a method to individualize the planning target volume (PTV) for deformable targets in radiotherapy by combining a computer tomography (CT) scan with multiple cone beam (CB)CT scans. All combinations of the CT and up to five initial CBCTs were considered. To exclude translational motion, the clinical target volumes (CTVs) in the CBCTs were matched to the CTV in the CT. PTVs investigated were the unions, the intersections and all other structures defined by a volume with a constant CTV location frequency. The method was investigated for three bladder cancer patients with a CT and 20-27 CBCTs. Reliable alternatives to a standard PTV required use of at least four scans for planning. The CTV unions of four or five scans gave similar results when considering the fraction of individual repeat scan CTVs they volumetrically covered to at least 99%. For patient 1, 64% of the repeat scan CTVs were covered by these unions and for patient 2, 86% were covered. Further, the PTVs defined by the volume occupied by the CTV in all except one of the four or five planning scans seemed clinically feasible. On average, 52% of the repeat CBCT CTVs for patient 1 and 64% for patient 2 were covered to minimum 99% of their total volume. For patient 3, the method failed due to poor volume control of the bladder. The suggested PTVs could, with considerably improved conformity, complement the standard PTV.

  14. Identifying radiotherapy target volumes in brain cancer by image analysis.

    PubMed

    Cheng, Kun; Montgomery, Dean; Feng, Yang; Steel, Robin; Liao, Hanqing; McLaren, Duncan B; Erridge, Sara C; McLaughlin, Stephen; Nailon, William H

    2015-10-01

    To establish the optimal radiotherapy fields for treating brain cancer patients, the tumour volume is often outlined on magnetic resonance (MR) images, where the tumour is clearly visible, and mapped onto computerised tomography images used for radiotherapy planning. This process requires considerable clinical experience and is time consuming, which will continue to increase as more complex image sequences are used in this process. Here, the potential of image analysis techniques for automatically identifying the radiation target volume on MR images, and thereby assisting clinicians with this difficult task, was investigated. A gradient-based level set approach was applied on the MR images of five patients with grades II, III and IV malignant cerebral glioma. The relationship between the target volumes produced by image analysis and those produced by a radiation oncologist was also investigated. The contours produced by image analysis were compared with the contours produced by an oncologist and used for treatment. In 93% of cases, the Dice similarity coefficient was found to be between 60 and 80%. This feasibility study demonstrates that image analysis has the potential for automatic outlining in the management of brain cancer patients, however, more testing and validation on a much larger patient cohort is required.

  15. Identifying radiotherapy target volumes in brain cancer by image analysis

    PubMed Central

    Cheng, Kun; Montgomery, Dean; Feng, Yang; Steel, Robin; Liao, Hanqing; McLaren, Duncan B.; Erridge, Sara C.; McLaughlin, Stephen

    2015-01-01

    To establish the optimal radiotherapy fields for treating brain cancer patients, the tumour volume is often outlined on magnetic resonance (MR) images, where the tumour is clearly visible, and mapped onto computerised tomography images used for radiotherapy planning. This process requires considerable clinical experience and is time consuming, which will continue to increase as more complex image sequences are used in this process. Here, the potential of image analysis techniques for automatically identifying the radiation target volume on MR images, and thereby assisting clinicians with this difficult task, was investigated. A gradient-based level set approach was applied on the MR images of five patients with grades II, III and IV malignant cerebral glioma. The relationship between the target volumes produced by image analysis and those produced by a radiation oncologist was also investigated. The contours produced by image analysis were compared with the contours produced by an oncologist and used for treatment. In 93% of cases, the Dice similarity coefficient was found to be between 60 and 80%. This feasibility study demonstrates that image analysis has the potential for automatic outlining in the management of brain cancer patients, however, more testing and validation on a much larger patient cohort is required. PMID:26609418

  16. Optimized planning target volume for intact cervical cancer.

    PubMed

    Khan, Alvin; Jensen, Lindsay G; Sun, Shuai; Song, William Y; Yashar, Catheryn M; Mundt, Arno J; Zhang, Fu-Quan; Jiang, Steve B; Mell, Loren K

    2012-08-01

    To model interfraction clinical target volume (CTV) variation in patients with intact cervical cancer and design a planning target volume (PTV) that minimizes normal tissue dose while maximizing CTV coverage. We analyzed 50 patients undergoing external-beam radiotherapy for intact cervical cancer using daily online cone-beam computed tomography (CBCT). The CBCTs (n = 972) for each patient were rigidly registered to the planning CT. The CTV was delineated on the planning CT (CTV(0)) and the set of CBCTs ({CTV(1)-CTV(25)}). Manual (n = 98) and automated (n = 668) landmarks were placed over the surface of CTV(0) with reference to defined anatomic structures. Normal vectors were extended from each landmark, and the minimum length required for a given probability of encompassing CTV(1)-CTV(25) was computed. The resulting expansions were used to generate an optimized PTV. The mean (SD; range) normal vector length to ensure 95% coverage was 4.3 mm (2.7 mm; 1-16 mm). The uniform expansion required to ensure 95% probability of CTV coverage was 13 mm. An anisotropic margin of 20 mm anteriorly and posteriorly and 10 mm superiorly, inferiorly, and laterally also would have ensured a 95% probability of CTV coverage. The volume of the 95% optimized PTV (1470 cm(3)) was significantly lower than both the anisotropic PTV (2220 cm(3)) and the uniformly expanded PTV (2110 cm(3)) (p < 0.001). For a 95% probability of CTV coverage, normal lengths of 1-3 mm were found along the superior and lateral regions of CTV(0), 5-10 mm along the interfaces of CTV(0) with the bladder and rectum, and 10-14 mm along the anterior surface of CTV(0) at the level of the uterus. Optimizing PTV definition according to surface landmarking resulted in a high probability of CTV coverage with reduced PTV volumes. Our results provide data justifying planning margins to use in practice and clinical trials. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Optimized Planning Target Volume for Intact Cervical Cancer

    SciTech Connect

    Khan, Alvin; Jensen, Lindsay G.; Sun Shuai; Song, William Y.; Yashar, Catheryn M.; Mundt, Arno J.; Zhang Fuquan; Jiang, Steve B.; Mell, Loren K.

    2012-08-01

    Purpose: To model interfraction clinical target volume (CTV) variation in patients with intact cervical cancer and design a planning target volume (PTV) that minimizes normal tissue dose while maximizing CTV coverage. Methods and Materials: We analyzed 50 patients undergoing external-beam radiotherapy for intact cervical cancer using daily online cone-beam computed tomography (CBCT). The CBCTs (n = 972) for each patient were rigidly registered to the planning CT. The CTV was delineated on the planning CT (CTV{sub 0}) and the set of CBCTs ({l_brace}CTV{sub 1}-CTV{sub 25}{r_brace}). Manual (n = 98) and automated (n = 668) landmarks were placed over the surface of CTV{sub 0} with reference to defined anatomic structures. Normal vectors were extended from each landmark, and the minimum length required for a given probability of encompassing CTV{sub 1}-CTV{sub 25} was computed. The resulting expansions were used to generate an optimized PTV. Results: The mean (SD; range) normal vector length to ensure 95% coverage was 4.3 mm (2.7 mm; 1-16 mm). The uniform expansion required to ensure 95% probability of CTV coverage was 13 mm. An anisotropic margin of 20 mm anteriorly and posteriorly and 10 mm superiorly, inferiorly, and laterally also would have ensured a 95% probability of CTV coverage. The volume of the 95% optimized PTV (1470 cm{sup 3}) was significantly lower than both the anisotropic PTV (2220 cm{sup 3}) and the uniformly expanded PTV (2110 cm{sup 3}) (p < 0.001). For a 95% probability of CTV coverage, normal lengths of 1-3 mm were found along the superior and lateral regions of CTV{sub 0}, 5-10 mm along the interfaces of CTV{sub 0} with the bladder and rectum, and 10-14 mm along the anterior surface of CTV{sub 0} at the level of the uterus. Conclusion: Optimizing PTV definition according to surface landmarking resulted in a high probability of CTV coverage with reduced PTV volumes. Our results provide data justifying planning margins to use in practice and

  18. Accuracy of TomoTherapy treatments for superficial target volumes.

    PubMed

    Cheek, Dennis; Gibbons, John P; Rosen, Isaac I; Hogstrom, Kenneth R

    2008-08-01

    Helical tomotherapy is a technique for delivering intensity modulated radiation therapy treatments using a continuously rotating linac. In this approach, fan beams exiting the linac are dynamically modulated in synchrony with the motion of the gantry and couch. Helical IMRT deliveries have been applied to treating surface lesions, and the purpose of this study was to evaluate the accuracy of dose calculated by the TomoTherapy HiArt treatment planning system for superficial planning target volumes (PTVs). TomoTherapy treatment plans were developed for three superficial PTVs (2-, 4-, and 6-cm deep radially by 90 degrees azimuthally by 4-cm longitudinally) contoured on a 27-cm diameter cylindrical white opaque, high-impact polystyrene phantom. The phantom included removable transverse and sagittal film cassettes that contained bare Kodak EDR2 films cut such that their edges matched the phantom surface (+/-0.05 cm). The phantom was aligned to the machine's isocenter (+/-0.05 cm) and was irradiated according to the treatment plans. Films were scanned with a Vidar film digitizer, and optical densities were converted to dose using a calibration determined from a 6 MV perpendicular film exposure. This perpendicular calibration required that axial film doses (parallel irradiation) be scaled by 1.02 so that mid-arc depth doses matched those measured in the sagittal plane (perpendicular irradiation). All film readings were scaled by 0.935 to correct for over-response due to phantom Cerenkov light. Measured dose distributions were registered to calculated ones and compared. Calculated doses overpredicted measured doses by as much as 9.5% of the prescribed dose at depths less than 1 cm. At depths greater than 1 cm, calculated dose distributions showed agreement to measurement within 5% in the high-dose region and within 0.2 cm distance-to-agreement in the dose falloff regions. In the low-dose region posterior to the PTVs (<10% of the prescribed dose), the dose algorithm

  19. Technology transfer from NASA to targeted industries, volume 2

    NASA Technical Reports Server (NTRS)

    Mccain, Wayne; Schroer, Bernard J.; Souder, William E.; Spann, Mary S.; Watters, Harry; Ziemke, M. Carl

    1993-01-01

    This volume contains the following materials to support Volume 1: (1) Survey of Metal Fabrication Industry in Alabama; (2) Survey of Electronics Manufacturing/Assembly Industry in Alabama; (3) Apparel Modular Manufacturing Simulators; (4) Synopsis of a Stereolithography Project; (5) Transferring Modular Manufacturing Technology to an Apparel Firm; (6) Letters of Support; (7) Fact Sheets; (8) Publications; and (9) One Stop Access to NASA Technology Brochure.

  20. Delineation of Supraclavicular Target Volumes in Breast Cancer Radiation Therapy

    SciTech Connect

    Brown, Lindsay C.; Diehn, Felix E.; Boughey, Judy C.; Childs, Stephanie K.; Park, Sean S.; Yan, Elizabeth S.; Petersen, Ivy A.; Mutter, Robert W.

    2015-07-01

    Purpose: To map the location of gross supraclavicular metastases in patients with breast cancer, in order to determine areas at highest risk of harboring subclinical disease. Methods and Materials: Patients with axial imaging of gross supraclavicular disease were identified from an institutional breast cancer registry. Locations of the metastatic lymph nodes were transferred onto representative axial computed tomography images of the supraclavicular region and compared with the Radiation Therapy Oncology Group (RTOG) breast cancer atlas for radiation therapy planning. Results: Sixty-two patients with 161 supraclavicular nodal metastases were eligible for study inclusion. At the time of diagnosis, 117 nodal metastases were present in 44 patients. Forty-four nodal metastases in 18 patients were detected at disease recurrence, 4 of whom had received prior radiation to the supraclavicular fossa. Of the 161 nodal metastases, 95 (59%) were within the RTOG consensus volume, 4 nodal metastases (2%) in 3 patients were marginally within the volume, and 62 nodal metastases (39%) in 30 patients were outside the volume. Supraclavicular disease outside the RTOG consensus volume was located in 3 regions: at the level of the cricoid and thyroid cartilage (superior to the RTOG volume), in the posterolateral supraclavicular fossa (posterolateral to the RTOG volume), and in the lateral low supraclavicular fossa (lateral to the RTOG volume). Only women with multiple supraclavicular metastases had nodal disease that extended superiorly to the level of the thyroid cartilage. Conclusions: For women with risk of harboring subclinical supraclavicular disease warranting the addition of supraclavicular radiation, coverage of the posterior triangle and the lateral low supraclavicular region should be considered. For women with known supraclavicular disease, extension of neck coverage superior to the cricoid cartilage may be warranted.

  1. Delineation of Supraclavicular Target Volumes in Breast Cancer Radiation Therapy.

    PubMed

    Brown, Lindsay C; Diehn, Felix E; Boughey, Judy C; Childs, Stephanie K; Park, Sean S; Yan, Elizabeth S; Petersen, Ivy A; Mutter, Robert W

    2015-07-01

    To map the location of gross supraclavicular metastases in patients with breast cancer, in order to determine areas at highest risk of harboring subclinical disease. Patients with axial imaging of gross supraclavicular disease were identified from an institutional breast cancer registry. Locations of the metastatic lymph nodes were transferred onto representative axial computed tomography images of the supraclavicular region and compared with the Radiation Therapy Oncology Group (RTOG) breast cancer atlas for radiation therapy planning. Sixty-two patients with 161 supraclavicular nodal metastases were eligible for study inclusion. At the time of diagnosis, 117 nodal metastases were present in 44 patients. Forty-four nodal metastases in 18 patients were detected at disease recurrence, 4 of whom had received prior radiation to the supraclavicular fossa. Of the 161 nodal metastases, 95 (59%) were within the RTOG consensus volume, 4 nodal metastases (2%) in 3 patients were marginally within the volume, and 62 nodal metastases (39%) in 30 patients were outside the volume. Supraclavicular disease outside the RTOG consensus volume was located in 3 regions: at the level of the cricoid and thyroid cartilage (superior to the RTOG volume), in the posterolateral supraclavicular fossa (posterolateral to the RTOG volume), and in the lateral low supraclavicular fossa (lateral to the RTOG volume). Only women with multiple supraclavicular metastases had nodal disease that extended superiorly to the level of the thyroid cartilage. For women with risk of harboring subclinical supraclavicular disease warranting the addition of supraclavicular radiation, coverage of the posterior triangle and the lateral low supraclavicular region should be considered. For women with known supraclavicular disease, extension of neck coverage superior to the cricoid cartilage may be warranted. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. High volume fabrication of laser targets using MEMS techniques

    NASA Astrophysics Data System (ADS)

    Spindloe, C.; Arthur, G.; Hall, F.; Tomlinson, S.; Potter, R.; Kar, S.; Green, J.; Higginbotham, A.; Booth, N.; Tolley, M. K.

    2016-04-01

    The latest techniques for the fabrication of high power laser targets, using processes developed for the manufacture of Micro-Electro-Mechanical System (MEMS) devices are discussed. These laser targets are designed to meet the needs of the increased shot numbers that are available in the latest design of laser facilities. Traditionally laser targets have been fabricated using conventional machining or coarse etching processes and have been produced in quantities of 10s to low 100s. Such targets can be used for high complexity experiments such as Inertial Fusion Energy (IFE) studies and can have many complex components that need assembling and characterisation with high precision. Using the techniques that are common to MEMS devices and integrating these with an existing target fabrication capability we are able to manufacture and deliver targets to these systems. It also enables us to manufacture novel targets that have not been possible using other techniques. In addition, developments in the positioning systems that are required to deliver these targets to the laser focus are also required and a system to deliver the target to a focus of an F2 beam at 0.1Hz is discussed.

  3. Analysis of Laser-Target Interaction. Volume 1. Theory

    DTIC Science & Technology

    1979-03-01

    Previously, a model was constructed to describe energy transfer to an aluminum alloy target A12024 by a plasma ignited over the target surface. 1,2 The...intensity absorbed by the three non- aluminum alloys is shown as a function of time. A similar plot for oxidized steel is given in Fig. 3. 5. Typical...such as aluminum or copper cover poorly con- ducting targets such as SS304 and Ti6Al4V. 347 For an aluminum target over an aluminum alloy , the substrate

  4. Atlas-based semiautomatic target volume definition (CTV) for head-and-neck tumors.

    PubMed

    Strassmann, Gerd; Abdellaoui, Soulimane; Richter, Detlef; Bekkaoui, Fayzal; Haderlein, Marlene; Fokas, Emmanouil; Timmesfeld, Nina; Vogel, Birgitt; Henzel, Martin; Engenhart-Cabillic, Rita

    2010-11-15

    To develop a new semiautomatic method to improve target delineation in head-and-neck cancer. We implemented an atlas-based software program using fourteen anatomic landmarks as well as the most superior and inferior computerd tomography slices for automatic target delineation, using an advanced laryngeal carcinoma as an example. Registration was made by an affine transformation. Evaluation was performed with manually drawn contours for comparison. Three physicians sampled and further applied a target volume atlas to ten other computer tomography data sets. In addition, a rapid three-dimensional (3D) correction program was developed. The mean time to the first semiautomatic target delineation proposal was 2.7 minutes. Manual contouring required 20.2 minutes per target, whereas semiautomatic target volume definition with the rapid 3D correction was completed in only 9.7 minutes. The net calculation time for image registration of the target volume atlas was negligible (approximately 0.6 seconds). Our method depicted a sufficient adaptation of the target volume atlas on the new data sets, with a mean similarity index of 77.2%. The similarity index increased up to 85% after 3D correction performed by the physicians. We have developed a new, feasible method for semiautomatic contouring that saves a significant amount (51.8%) of target delineation time for head-and-neck cancer patients. This approach uses a target volume atlas and a landmark model. The software was evaluated by means of laryngeal cancer but has important implications for various tumor types whereby target volumes remain constant in form and do not move with respiration. Copyright © 2010 Elsevier Inc. All rights reserved.

  5. Atlas-Based Semiautomatic Target Volume Definition (CTV) for Head-and-Neck Tumors

    SciTech Connect

    Strassmann, Gerd; Abdellaoui, Soulimane; Richter, Detlef; Bekkaoui, Fayzal; Haderlein, Marlene; Fokas, Emmanouil; Timmesfeld, Nina; Vogel, Birgitt M.D.; Henzel, Martin; Engenhart-Cabillic, Rita

    2010-11-15

    Purpose: To develop a new semiautomatic method to improve target delineation in head-and-neck cancer. Methods and Materials: We implemented an atlas-based software program using fourteen anatomic landmarks as well as the most superior and inferior computerd tomography slices for automatic target delineation, using an advanced laryngeal carcinoma as an example. Registration was made by an affine transformation. Evaluation was performed with manually drawn contours for comparison. Three physicians sampled and further applied a target volume atlas to ten other computer tomography data sets. In addition, a rapid three-dimensional (3D) correction program was developed. Results: The mean time to the first semiautomatic target delineation proposal was 2.7 minutes. Manual contouring required 20.2 minutes per target, whereas semiautomatic target volume definition with the rapid 3D correction was completed in only 9.7 minutes. The net calculation time for image registration of the target volume atlas was negligible (approximately 0.6 seconds). Our method depicted a sufficient adaptation of the target volume atlas on the new data sets, with a mean similarity index of 77.2%. The similarity index increased up to 85% after 3D correction performed by the physicians. Conclusions: We have developed a new, feasible method for semiautomatic contouring that saves a significant amount (51.8%) of target delineation time for head-and-neck cancer patients. This approach uses a target volume atlas and a landmark model. The software was evaluated by means of laryngeal cancer but has important implications for various tumor types whereby target volumes remain constant in form and do not move with respiration.

  6. Technology transfer from NASA to targeted industries, volume 1

    NASA Technical Reports Server (NTRS)

    Mccain, Wayne; Schroer, Bernard J.; Souder, William E.; Spann, Mary S.; Watters, Harry; Ziemke, M. Carl

    1993-01-01

    This report summarizes the University of Alabama in Huntsville (UAH) technology transfer to three target industries with focus on the apparel manufacturing industry in Alabama. Also included in this report are an analysis of the 1992 problem statements submitted by Alabama firms, the results of the survey of 1987-88 NASA Tech Brief requests, the results of the followup to Alabama submitted problem statements, and the development of the model describing the MSFC technology transfer process.

  7. International Spine Radiosurgery Consortium Consensus Guidelines for Target Volume Definition in Spinal Stereotactic Radiosurgery

    SciTech Connect

    Cox, Brett W.; Spratt, Daniel E.; Lovelock, Michael; Bilsky, Mark H.; Lis, Eric; Ryu, Samuel; Sheehan, Jason; Gerszten, Peter C.; Chang, Eric; Gibbs, Iris; Soltys, Scott; Sahgal, Arjun; Deasy, Joe; Flickinger, John; Quader, Mubina; Mindea, Stefan; and others

    2012-08-01

    Purpose: Spinal stereotactic radiosurgery (SRS) is increasingly used to manage spinal metastases. However, target volume definition varies considerably and no consensus target volume guidelines exist. This study proposes consensus target volume definitions using common scenarios in metastatic spine radiosurgery. Methods and Materials: Seven radiation oncologists and 3 neurological surgeons with spinal radiosurgery expertise independently contoured target and critical normal structures for 10 cases representing common scenarios in metastatic spine radiosurgery. Each set of volumes was imported into the Computational Environment for Radiotherapy Research. Quantitative analysis was performed using an expectation maximization algorithm for Simultaneous Truth and Performance Level Estimation (STAPLE) with kappa statistics calculating agreement between physicians. Optimized confidence level consensus contours were identified using histogram agreement analysis and characterized to create target volume definition guidelines. Results: Mean STAPLE agreement sensitivity and specificity was 0.76 (range, 0.67-0.84) and 0.97 (range, 0.94-0.99), respectively, for gross tumor volume (GTV) and 0.79 (range, 0.66-0.91) and 0.96 (range, 0.92-0.98), respectively, for clinical target volume (CTV). Mean kappa agreement was 0.65 (range, 0.54-0.79) for GTV and 0.64 (range, 0.54-0.82) for CTV (P<.01 for GTV and CTV in all cases). STAPLE histogram agreement analysis identified optimal consensus contours (80% confidence limit). Consensus recommendations include that the CTV should include abnormal marrow signal suspicious for microscopic invasion and an adjacent normal bony expansion to account for subclinical tumor spread in the marrow space. No epidural CTV expansion is recommended without epidural disease, and circumferential CTVs encircling the cord should be used only when the vertebral body, bilateral pedicles/lamina, and spinous process are all involved or there is extensive metastatic

  8. Monte Carlo Simulations for Dosimetry in Prostate Radiotherapy with Different Intravesical Volumes and Planning Target Volume Margins

    PubMed Central

    Lv, Wei; Yu, Dong; He, Hengda; Liu, Qian

    2016-01-01

    In prostate radiotherapy, the influence of bladder volume variation on the dose absorbed by the target volume and organs at risk is significant and difficult to predict. In addition, the resolution of a typical medical image is insufficient for visualizing the bladder wall, which makes it more difficult to precisely evaluate the dose to the bladder wall. This simulation study aimed to quantitatively investigate the relationship between the dose received by organs at risk and the intravesical volume in prostate radiotherapy. The high-resolution Visible Chinese Human phantom and the finite element method were used to construct 10 pelvic models with specific intravesical volumes ranging from 100 ml to 700 ml to represent bladders of patients with different bladder filling capacities during radiotherapy. This series of models was utilized in six-field coplanar 3D conformal radiotherapy simulations with different planning target volume (PTV) margins. Each organ’s absorbed dose was calculated using the Monte Carlo method. The obtained bladder wall displacements during bladder filling were consistent with reported clinical measurements. The radiotherapy simulation revealed a linear relationship between the dose to non-targeted organs and the intravesical volume and indicated that a 10-mm PTV margin for a large bladder and a 5-mm PTV margin for a small bladder reduce the effective dose to the bladder wall to similar degrees. However, larger bladders were associated with evident protection of the intestines. Detailed dosimetry results can be used by radiation oncologists to create more accurate, individual water preload protocols according to the patient’s anatomy and bladder capacity. PMID:27441944

  9. A prediction model of radiation-induced necrosis for intracranial radiosurgery based on target volume.

    PubMed

    Zhao, Bo; Wen, Ning; Chetty, Indrin J; Huang, Yimei; Brown, Stephen L; Snyder, Karen C; Siddiqui, Farzan; Movsas, Benjamin; Siddiqui, M Salim

    2017-08-01

    This study aims to extend the observation that the 12 Gy-radiosurgical-volume (V12Gy) correlates with the incidence of radiation necrosis in patients with intracranial tumors treated with radiosurgery by using target volume to predict V12Gy. V12Gy based on the target volume was used to predict the radiation necrosis probability (P) directly. Also investigated was the reduction in radiation necrosis rates (ΔP) as a result of optimizing the prescription isodose lines for linac-based SRS. Twenty concentric spherical targets and 22 patients with brain tumors were retrospectively studied. For each case, a standard clinical plan and an optimized plan with prescription isodose lines based on gradient index were created. V12Gy were extracted from both plans to analyze the correlation between V12Gy and target volume. The necrosis probability P as a function of V12Gy was evaluated. To account for variation in prescription, the relation between V12Gy and prescription was also investigated. A prediction model for radiation-induced necrosis was presented based on the retrospective study. The model directly relates the typical prescribed dose and the target volume to the radionecrosis probability; V12Gy increased linearly with the target volume (R(2)  > 0.99). The linear correlation was then integrated into a logistic model to predict P directly from the target volume. The change in V12Gy as a function of prescription was modeled using a single parameter, s (=-1.15). Relatively large ΔP was observed for target volumes between 7 and 28 cm(3) with the maximum reduction (8-9%) occurring at approximately 18 cm(3) . Based on the model results, optimizing the prescription isodose line for target volumes between 7 and 28 cm(3) results in a significant reduction in necrosis probability. V12Gy based on the target volume could provide clinicians a predictor of radiation necrosis at the contouring stage thus facilitating treatment decisions. © 2017 American Association of

  10. [Multimodalities imaging for target volume definition in radiotherapy].

    PubMed

    Daisne, Jean-François; Grégoire, Vincent

    2006-12-01

    Modern radiotherapy delivery nowadays relies on tridimensional, conformal techniques. The aim is to better target the tumor while decreasing the dose administered to surrounding normal tissues. Gold standard imaging modality remains computed-tomography (CT) scanner. However, the intrinsic lack of contrast between soft tissues leads to high variabilities in target definition. The risks are : a geographical miss with tumor underirradiation on the one hand, and a tumor overestimation with undue normal tissues irradiation on the other hand. Alternative imaging modalities like magnetic resonance imaging and functional positron emission tomography could theoretically overcome the lack of soft tissues contrast of CT. However, the fusion of the different imaging modalities images requires the use of sophisticated computer algorithms. We will briefly review them. We will then review the different clinical results reported with multi-modalities imaging for tumors of the head, neck, lung, esophagus, cervix and lymphomas. Finally, we will briefly give practical recommendations for multi-modality imaging in radiotherapy treatment planning process.

  11. Cone-Beam CT Localization of Internal Target Volumes for Stereotactic Body Radiotherapy of Lung Lesions

    SciTech Connect

    Wang Zhiheng Wu, Q. Jackie; Marks, Lawrence B.; Larrier, Nicole; Yin Fangfang

    2007-12-01

    Purpose: In this study, we investigate a technique of matching internal target volumes (ITVs) in four-dimensional (4D) simulation computed tomography (CT) to the composite target volume in free-breathing on-board cone-beam (CB) CT. The technique is illustrated by using both phantom and patient cases. Methods and Materials: A dynamic phantom with a target ball simulating respiratory motion with various amplitude and cycle times was used to verify localization accuracy. The dynamic phantom was scanned using simulation CT with a phase-based retrospective sorting technique. The ITV was then determined based on 10 sets of sorted images. The size and epicenter of the ITV identified from 4D simulation CT images and the composite target volume identified from on-board CBCT images were compared to assess localization accuracy. Similarly, for two clinical cases of patients with lung cancer, ITVs defined from 4D simulation CT images and CBCT images were compared. Results: For the phantom, localization accuracy between the ITV in 4D simulation CT and the composite target volume in CBCT was within 1 mm, and ITV was within 8.7%. For patient cases, ITVs on simulation CT and CBCT were within 8.0%. Conclusion: This study shows that CBCT is a useful tool to localize ITV for targets affected by respiratory motion. Verification of the ITV from 4D simulation CT using on-board free-breathing CBCT is feasible for the target localization of lung tumors.

  12. Evaluation of Peritumoral Edema in the Delineation of Radiotherapy Clinical Target Volumes for Glioblastoma

    SciTech Connect

    Chang, Eric L. . E-mail: echang@mdanderson.org; Akyurek, Serap; Avalos, Tedde C; Rebueno, Neal C; Spicer, Chris C; Garcia, John C; Famiglietti, Robin; Allen, Pamela K.; Chao, K.S. Clifford; Mahajan, Anita; Woo, Shiao Y.; Maor, Moshe H.

    2007-05-01

    Purpose: To evaluate the spatial relationship between peritumoral edema and recurrence pattern in patients with glioblastoma (GBM). Methods and Materials: Forty-eight primary GBM patients received three-dimensional conformal radiotherapy that did not intentionally include peritumoral edema within the clinical target volume between July 2000 and June 2001. All 48 patients have subsequently recurred, and their original treatment planning parameters were used for this study. New theoretical radiation treatment plans were created for the same 48 patients, based on Radiation Therapy Oncology Group (RTOG) target delineation guidelines that specify inclusion of peritumoral edema. Target volume and recurrent tumor coverage, as well as percent volume of normal brain irradiated, were assessed for both methods of target delineation using dose-volume histograms. Results: A comparison between the location of recurrent tumor and peritumoral edema volumes from all 48 cases failed to show correlation by linear regression modeling (r {sup 2} 0.0007; p = 0.3). For patients with edema >75 cm{sup 3}, the percent volume of brain irradiated to 46 Gy was significantly greater in treatment plans that intentionally included peritumoral edema compared with those that did not (38% vs. 31%; p = 0.003). The pattern of failure was identical between the two sets of plans (40 central, 3 in-field, 3 marginal, and 2 distant recurrence). Conclusion: Clinical target volume delineation based on a 2-cm margin rather than on peritumoral edema did not seem to alter the central pattern of failure for patients with GBM. For patients with peritumoral edema >75 cm{sup 3}, using a constant 2-cm margin resulted in a smaller median percent volume of brain being irradiated to 30 Gy, 46 Gy, and 50 Gy compared with corresponding theoretical RTOG plans that deliberately included peritumoral edema.

  13. Inter- and Intrafractional Movement-Induced Dose Reduction of Prostate Target Volume in Proton Beam Treatment

    SciTech Connect

    Yoon, Myonggeun; Kim, Dongwook; Shin, Dong Ho; Park, Sung Yong Lee, Se Byeong; Kim, Dae Yong; Kim, Joo Young; Pyo, Hong Ryull; Cho, Kwan Ho

    2008-07-15

    Purpose: To quantify proton radiotherapy dose reduction in the prostate target volume because of the three-dimensional movement of the prostate based on an analysis of dose-volume histograms (DVHs). Methods and Materials: Twelve prostate cancer patients underwent scanning in supine position, and a target contour was delineated for each using a proton treatment planning system. To simulate target movement, the contour was displaced from 3 to 15 mm in 3-mm intervals in the superior-to-inferior (SI), inferior-to-superior (IS), anterior-to-posterior (AP), posterior-to-anterior (PA), and left-to-right (LR) directions. Results: For both intra- and interfractional movements, the average coverage index and conformity index of the target were reduced in all directions. For interfractional movements, the magnitude of dose reduction was greater in the LR direction than in the AP, PA, SI. and IS directions. Although the reduction of target dose was proportional to the magnitude of intrafractional movement in all directions, a proportionality between dose reduction and the magnitude of interfractional target movement was clear only in the LR direction. Like the coverage index and conformity index, the equivalent uniform dose and homogeneity index showed similar reductions for both types of target movements. Conclusions: Small target movements can significantly reduce target proton radiotherapy dose during treatment of prostate cancer patients. Attention should be given to interfractional target movement along the longitudinal direction, as image-guided radiotherapy may be ineffective if margins are not sufficient.

  14. [Definition of accurate planning target volume margins for esophageal cancer radiotherapy].

    PubMed

    Lesueur, P; Servagi-Vernat, S

    2016-10-01

    More than 4000 cases of esophagus neoplasms are diagnosed every year in France. Radiotherapy, which can be delivered in preoperative or exclusive with a concomitant chemotherapy, plays a central role in treatment of esophagus cancer. Even if efficacy of radiotherapy no longer has to be proved, the prognosis of esophagus cancer remains unfortunately poor with a high recurrence rate. Toxicity of esophageal radiotherapy is correlated with the irradiation volume, and limits dose escalation and local control. Esophagus is a deep thoracic organ, which undergoes cardiac and respiratory motion, making the radiotherapy delivery more difficult and increasing the planning target volume margins. Definition of accurate planning target volume margins, taking into account the esophagus' intrafraction motion and set up margins is very important to be sure to cover the clinical target volume and restrains acute and late radiotoxicity. In this article, based on a review of the literature, we propose planning target volume margins adapted to esophageal radiotherapy. Copyright © 2016 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  15. Magnetic Resonance Imaging- Versus Computed Tomography-Based Target Volume Delineation of the Glandular Breast Tissue (Clinical Target Volume Breast) in Breast-Conserving Therapy: An Exploratory Study

    SciTech Connect

    Giezen, Marina; Kouwenhoven, Erik; Scholten, Astrid N.; Coerkamp, Emile G.; Heijenbrok, Mark; Jansen, Wim P.A.; Mast, Mirjam E.; Petoukhova, Anna L.; Struikmans, Henk

    2011-11-01

    Purpose: To examine MRI and CT for glandular breast tissue (GBT) volume delineation and to assess interobserver variability. Methods and Materials: Fifteen breast cancer patients underwent a planning CT and MRI, consecutively, in the treatment position. Four observers (two radiation oncologists and two radiologists) delineated the GBT according to the CT and separately to the MR images. Volumes, centers of mass, maximum extensions with standard deviations (SD), and interobserver variability were quantified. Observers viewed delineation differences between MRI and CT and delineation differences among observers. Results: In cranio-lateral and cranio-medial directions, GBT volumes were delineated larger using MRI when compared with those delineated with CT. Center of mass on MRI shifted a mean (SD) 17% (4%) into the cranial direction and a mean 3% (4%) into the dorsal direction when compared with that on the planning CT. Only small variations between observers were noted. The GBT volumes were approximately 4% larger on MRI (mean [SD] ratio MRI to CT GBT volumes, 1.04 [0.06]). Findings were concordant with viewed MRI and CT images and contours. Conformity indices were only slightly different; mean conformity index was 77% (3%) for MRI and 79% (4%) for CT. Delineation differences arising from personal preferences remained recognizable irrespective of the imaging modality used. Conclusions: Contoured GBT extends substantially further into the cranio-lateral and cranio-medial directions on MRI when compared with CT. Interobserver variability is comparable for both imaging modalities. Observers should be aware of existing personal delineation preferences. Institutions are recommended to review and discuss target volume delineations and to design supplementary guidelines if necessary.

  16. New conformity indices based on the calculation of distances between the target volume and the volume of reference isodose

    PubMed Central

    Park, J M; Park, S-Y; Ye, S-J; Kim, J H; Carlson, J

    2014-01-01

    Objective: To present conformity indices (CIs) based on the distance differences between the target volume (TV) and the volume of reference isodose (VRI). Methods: The points on the three-dimensional surfaces of the TV and the VRI were generated. Then, the averaged distances between the points on the TV and the VRI were calculated (CIdistance). The performance of the presented CIs were evaluated by analysing six situations, which were a perfect match, an expansion and a reduction of the distance from the centroid to the VRI compared with the distance from the centroid to the TV by 10%, a lateral shift of the VRI by 3 cm, a rotation of the VRI by 45° and a spherical-shaped VRI having the same volume as the TV. The presented CIs were applied to the clinical prostate and head and neck (H&N) plans. Results: For the perfect match, CIdistance was 0 with 0 as the standard deviation (SD). When expanding and reducing, CIdistance was 10 and −10 with SDs <1.3, respectively. With shifting and rotating of the VRI, the CIdistance was almost 0 with SDs >11. The average value of the CIdistance in the prostate and H&N plans was 0.13 ± 7.44 and 6.04 ± 23.27, respectively. Conclusion: The performance of the CIdistance was equal or better than those of the conventional CIs. Advances in knowledge: The evaluation of target conformity by the distances between the surface of the TV and the VRI could be more accurate than evaluation with volume information. PMID:25225915

  17. Lymphatic atlas-based target volume definition for intensity-modulated radiation therapy planning

    NASA Astrophysics Data System (ADS)

    Qatarneh, S. M.; Kiricuta, I. C.; Brahme, A.; Noz, M. E.; Ferreira, B.; Kim, W. C.; Lind, B. K.

    2007-10-01

    Despite the improvements in current imaging modalities such as CT and MRI, the detection of normal or malignant lymph nodes remains a challenge due to the large variability in lymph node characteristics and the variation in imaging quality and the limited imaging resolution. A computerized lymph node atlas could be the ideal tool for target volume definition based on the distribution of normal lymph nodes surrounding the verified malignant nodes to improve the accuracy of intensity-modulated radiation therapy planning. The standard lymph node topography in the newly constructed 3D lymph node atlas offers a detailed topographical distribution of discrete nodal locations in relation to surrounding organs at risk. In the present paper, the recently developed lymph node atlas is used for selection and delineation of target volumes in the head and neck, thorax and pelvic region. Image registration techniques were implemented to integrate the topography of the lymph node atlas into the patient's data set. By combining the knowledge-based lymph node distribution with the patient's data set, more detailed definitions of the target volumes were obtained to facilitate biologically based treatment plan optimization. The response values of the biologically optimized treatment plans were used to derive the probability of tumor control and the probability of complications in organs at risk. The treatment outcome of the lung reference plan showed a lower probability of recurrence in comparison to planning without the lymph node atlas. The lymph node atlas can improve and standardize the target volume definition by including more accurate anatomical knowledge for target volume definition and biologically optimized radiation therapy planning.

  18. Three dimensional planning target volumes: a model and a software tool.

    PubMed

    Austin-Seymour, M; Kalet, I; McDonald, J; Kromhout-Schiro, S; Jacky, J; Hummel, S; Unger, J

    1995-12-01

    Three dimensional (3D) target volumes are an essential component of conformal therapy because the goal is to shape the treatment volume to the target volume. The planning target volume (PTV) is defined by ICRU 50 as the clinical target volume (CTV) plus a margin to ensure that the CTV receives the prescribed dose. The margin must include all interfractional and intrafractional treatment variations. This paper describes a software tool that automatically generates 3D PTVs from CTVs for lung cancers and immobile head and neck cancers. Values for the interfractional and intrafractional treatment variations were determined by a literature review and by targeted interviews with physicians. The software tool is written in Common LISP and conforms to the specifications for shareable software of the Radiotherapy Treatment Planning Tools Collaborative Working Group. The tool is a rule-based expert system in which the inputs are the CTV contours, critical structure contours, and qualitative information about the specific patient. The output is PTV contours, which are a cylindrical expansion of the CTV. A model for creating PTVs from CTVs is embedded in the tool. The interfractional variation of setup uncertainty and the intrafractional variations of movement of the CTV (e.g., respiration) and patient motion are included in the model. Measured data for the component variations is consistent with modeling the components as independent samples from 3D Gaussian distributions. The components are combined using multivariate normal statistics to yield the cylindrical expansion factors. Rules are used to represent the values of the components for certain patient conditions (e.g., setup uncertainty for a head and neck patient immobilized in a mask). The tool uses a rule interpreter to combine qualitative information about a specific patient with rules representing the value of the components and to enter the appropriate component values for that patient into the cylindrical expansion

  19. Comparison of three image segmentation techniques for target volume delineation in positron emission tomography.

    PubMed

    Drever, Laura A; Roa, Wilson; McEwan, Alexander; Robinson, Don

    2007-03-09

    Incorporation of positron emission tomography (PET) data into radiotherapy planning is currently under investigation for numerous sites including lung, brain, head and neck, breast, and prostate. Accurate tumor-volume quantification is essential to the proper utilization of the unique information provided by PET. Unfortunately,target delineation within PET currently remains a largely unaddressed problem. We therefore examined the ability of three segmentation methods-thresholding, Sobel edge detection, and the watershed approach-to yield accurate delineation of PET target cross-sections. A phantom study employing well-defined cylindrical and spherical volumes and activity distributions provided an opportunity to assess the relative efficacy with which the three approaches could yield accurate target delineation in PET. Results revealed that threshold segmentation can accurately delineate target cross-sections, but that the Sobel and watershed techniques both consistently fail to correctly identify the size of experimental volumes. The usefulness of threshold-based segmentation is limited, however, by the dependence of the correct threshold (that which returns the correct area at each image slice) on target size.

  20. Comparison of four radiofrequency ablation systems at two target volumes in an ex vivo bovine liver model

    PubMed Central

    Rathke, Hendrik; Hamm, Bernd; Güttler, Felix; Rathke, Joern; Rump, Jens; Teichgräber, Ulf; de Bucourt, Maximilian

    2014-01-01

    PURPOSE We aimed to validate actually achieved macroscopic ablation volumes in relation to calculated target volumes using four different radiofrequency ablation (RFA) systems operated with default settings and protocols for 3 cm and 5 cm target volumes in ex vivo bovine liver. MATERIALS AND METHODS Sixty-four cuboid liver specimens were ablated with four commercially available RFA systems (Radionics Cool-tip, AngioDynamic 1500X, Boston Scientific RF 3000, Celon CelonPower LAB): 16 specimens for each system; eight for 3 cm, and eight for 5 cm. Ablation diameters were measured, volumes were calculated, and RFA times were recorded. RESULTS For the 3 cm target ablation volume, all tested RFA systems exceeded the mathematically calculated volume of 14.14 cm3. For the 3 cm target ablation volume, mean ablation volume and mean ablation time for each RFA system were as follows: 28.5±6.5 cm3, 12.0±0.0 min for Radionics Cool-tip; 17.1±4.9 cm3, 9.36±0.63 min for AngioDynamic 1500X; 29.7±11.7 cm3, 4.60±0.50 min for Boston Scientific RF 3000; and 28.8±7.0 cm3, 20.85±0.86 min for Celon Celon-Power LAB. For the 5 cm target ablation volume, Radionics Cool-tip (48.3±9.9 cm3, 12.0±0.0 min) and AngioDynamic 1500X (39.4±16.2 cm3, 19.59±1.13 min) did not reach the mathematically calculated target ablation volume (65.45 cm3), whereas Boston Scientific RF 3000 (71.8±14.5 cm3, 9.15±2.93 min) and Celon CelonPower LAB (93.9±28.1 cm3, 40.21±1.78 min) exceeded it. CONCLUSION While all systems reached the 3 cm target ablation volume, results were variable for the 5 cm target ablation volume. Only Boston Scientific RF 3000 and Celon CelonPower LAB created volumes above the target, whereas Radionics Cool-tip and AngioDynamic 1500X remained below the target volume. For the 3 cm target ablation volume, AngioDynamic 1500X with 21% deviation was closest to the target volume. For the 5 cm target volume Boston Scientific RF 3000 with 10% deviation was closest. PMID:24509185

  1. Comparison of four radiofrequency ablation systems at two target volumes in an ex vivo bovine liver model.

    PubMed

    Rathke, Hendrik; Hamm, Bernd; Güttler, Felix; Rathke, Joern; Rump, Jens; Teichgräber, Ulf; de Bucourt, Maximilian

    2014-01-01

    We aimed to validate actually achieved macroscopic ablation volumes in relation to calculated target volumes using four different radiofrequency ablation (RFA) systems operated with default settings and protocols for 3 cm and 5 cm target volumes in ex vivo bovine liver. Sixty-four cuboid liver specimens were ablated with four commercially available RFA systems (Radionics Cool-tip, AngioDynamic 1500X, Boston Scientific RF 3000, Celon CelonPower LAB): 16 specimens for each system; eight for 3 cm, and eight for 5 cm. Ablation diameters were measured, volumes were calculated, and RFA times were recorded. For the 3 cm target ablation volume, all tested RFA systems exceeded the mathematically calculated volume of 14.14 cm3. For the 3 cm target ablation volume, mean ablation volume and mean ablation time for each RFA system were as follows: 28.5 ± 6.5 cm3, 12.0 ± 0.0 min for Radionics Cool-tip; 17.1 ± 4.9 cm3, 9.36 ± 0.63 min for AngioDynamic 1500X; 29.7 ± 11.7 cm3, 4.60 ± 0.50 min for Boston Scientific RF 3000; and 28.8 ± 7.0 cm3, 20.85 ± 0.86 min for Celon CelonPower LAB. For the 5 cm target ablation volume, Radionics Cool-tip (48.3 ± 9.9 cm3, 12.0 ± 0.0 min) and AngioDynamic 1500X (39.4 ± 16.2 cm3, 19.59 ± 1.13 min) did not reach the mathematically calculated target ablation volume (65.45 cm3), whereas Boston Scientific RF 3000 (71.8 ± 14.5 cm3, 9.15 ± 2.93 min) and Celon CelonPower LAB (93.9 ± 28.1 cm3, 40.21 ± 1.78 min) exceeded it. While all systems reached the 3 cm target ablation volume, results were variable for the 5 cm target ablation volume. Only Boston Scientific RF 3000 and Celon CelonPower LAB created volumes above the target, whereas Radionics Cool-tip and AngioDynamic 1500X remained below the target volume. For the 3 cm target ablation volume, AngioDynamic 1500X with 21% deviation was closest to the target volume. For the 5 cm target volume Boston Scientific RF 3000 with 10% deviation was closest.

  2. [Organs at risk and target volumes: definition for conformal radiation therapy in breast cancer].

    PubMed

    Atean, I; Pointreau, Y; Barillot, I; Kirova, Y-M

    2012-09-01

    Adjuvant radiotherapy is a standard component of breast cancer treatment. The addition of radiotherapy after breast conserving surgery has been shown to reduce local recurrence rate and improve long-term survival. Accurate delineation of target volumes and organs at risk is crucial to the quality of treatment planning and delivered accomplished with innovate technologies in radiation therapy. This allows the radiation beam to be shaped specifically to each individual patient's anatomy. Target volumes include the mammary gland and surgical bed in case of breast conserving surgery, the chest wall in case of mastectomy, and if indicated, regional lymph nodes (axillary, supra- and infraclavicular and internal mammary). Organs at risk include lungs, thyroid, brachial plexus, heart, spinal cord and oesophagus. The aim of this article is to encourage the use of conformal treatment and delineation of target volumes and organs at risk and to describe specifically the definition of these volumes. Copyright © 2012 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  3. The effect of image-guided radiation therapy on the margin between the clinical target volume and planning target volume in lung cancer

    SciTech Connect

    Liang, Jun; Li, Minghui; Zhang, Tao; Han, Wei; Chen, Dongfu; Hui, Zhouguang; Lv, Jima; Zhang, Zhong; Zhang, Yin; Zhang, Liansheng; Zheng, Rong; Dai, Jianrong; Wang, Luhua

    2014-02-15

    Introduction: This study aimed to evaluate the effect of image-guided radiation therapy (IGRT) on the margin between the clinical target volume (CTV) and planning target volume (PTV) in lung cancer. Methods: The CTV and PTV margin were determined in three dimensions by four radiation oncologists using a standard method in 10 lung cancer patients, and compared to consensus values. Transfer error was measured using a rigid phantom containing gold markers. Systematic error and random error set up errors were calculated in three dimensions from pre-treatment and post-treatment cone beam CT scans. Finally, the margin between the CTV and PTV was corrected for set up error and calculated. Results: The margins between the CTV and PTV with IGRT (and without IGRT) were 0.88 cm (0.96 cm), 0.99 cm (1.08 cm) and 1.28 cm (1.82 cm) in the anterior and posterior (AP), left and right (LR) and superior and inferior (SI) directions, respectively. Images from two other patients verified the validity of the corrected margin. The target delineation errors of the radiation oncologists are considered to be the largest compared with the set up errors. The application of IGRT reduced the set up errors and the margins between CTV and PTV. Conclusions: The delineation errors of radiation oncologists are the most important factor to consider for the margin between CTV and PTV for lung cancer. IGRT can reduce the margins by reducing the set up errors, especially in the SI direction. Further research is required to assess whether the reduction in the margin is solely based on set up errors.

  4. Variations of target volume definition and daily target volume localization in stereotactic body radiotherapy for early-stage non-small cell lung cancer patients under abdominal compression.

    PubMed

    Han, Chunhui; Sampath, Sagus; Schultheisss, Timothy E; Wong, Jeffrey Y C

    2017-01-01

    We aimed to compare gross tumor volumes (GTV) in 3-dimensional computed tomography (3DCT) simulation and daily cone beam CT (CBCT) with the internal target volume (ITV) in 4-dimensional CT (4DCT) simulation in stereotactic body radiotherapy (SBRT) treatment of patients with early-stage non-small cell lung cancer (NSCLC) under abdominal compression. We retrospectively selected 10 patients with NSCLC who received image-guided SBRT treatments under abdominal compression with daily CBCT imaging. GTVs were contoured as visible gross tumor on the planning 3DCT and daily CBCT, and ITVs were contoured using maximum intensity projection (MIP) images of the planning 4DCT. Daily CBCTs were registered with 3DCT and MIP images by matching of bony landmarks in the thoracic region to evaluate interfractional GTV position variations. Relative to MIP-based ITVs, the average 3DCT-based GTV volume was 66.3 ± 17.1% (range: 37.5% to 92.0%) (p < 0.01 in paired t-test), and the average CBCT-based GTV volume was 90.0 ± 6.7% (daily range: 75.7% to 107.1%) (p = 0.02). Based on bony anatomy matching, the center-of-mass coordinates for CBCT-based GTVs had maximum absolute shift of 2.4 mm (left-right), 7.0 mm (anterior-posterior [AP]), and 5.2 mm (superior-inferior [SI]) relative to the MIP-based ITV. CBCT-based GTVs had average overlapping ratio of 81.3 ± 11.2% (range: 45.1% to 98.9%) with the MIP-based ITV, and 57.7 ± 13.7% (range: 35.1% to 83.2%) with the 3DCT-based GTV. Even with abdominal compression, both 3DCT simulations and daily CBCT scans significantly underestimated the full range of tumor motion. In daily image-guided patient setup corrections, automatic bony anatomy-based image registration could lead to target misalignment. Soft tissue-based image registration should be performed for accurate treatment delivery. Copyright © 2017 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  5. A two isocenter IMRT technique with a controlled junction dose for long volume targets

    NASA Astrophysics Data System (ADS)

    Zeng, G. G.; Heaton, R. K.; Catton, C. N.; Chung, P. W.; O'Sullivan, B.; Lau, M.; Parent, A.; Jaffray, D. A.

    2007-07-01

    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 throughout a junction region of 4-6 cm to minimize the impact of field match errors on a junction dose and manipulates the inverse planning and IMRT segments to fill in the dose gradient and achieve dose uniformity. Techniques for abutting both conventional fields with IMRT ('Static + IMRT') and IMRT fields ('IMRT + IMRT') using two separate isocenters have been developed. Five long volume sarcoma cases have been planned in Pinnacle (Philips, Madison, USA) using Elekta Synergy and Varian 2100EX linacs; two of the cases were clinically treated with this technique. Advantages were demonstrated with well-controlled junction target uniformity and tolerance to setup uncertainties. The junction target dose heterogeneity was controlled at a level of ±5% for 3 mm setup errors at the field edges, the junction target dose changed less than 5% and the dose sparing to organs at risk (OARs) was maintained. Film measurements confirmed the treatment planning results.

  6. A two isocenter IMRT technique with a controlled junction dose for long volume targets.

    PubMed

    Zeng, G G; Heaton, R K; Catton, C N; Chung, P W; O'Sullivan, B; Lau, M; Parent, A; Jaffray, D A

    2007-08-07

    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 throughout a junction region of 4-6 cm to minimize the impact of field match errors on a junction dose and manipulates the inverse planning and IMRT segments to fill in the dose gradient and achieve dose uniformity. Techniques for abutting both conventional fields with IMRT ('Static + IMRT') and IMRT fields ('IMRT + IMRT') using two separate isocenters have been developed. Five long volume sarcoma cases have been planned in Pinnacle (Philips, Madison, USA) using Elekta Synergy and Varian 2100EX linacs; two of the cases were clinically treated with this technique. Advantages were demonstrated with well-controlled junction target uniformity and tolerance to setup uncertainties. The junction target dose heterogeneity was controlled at a level of +/-5%; for 3 mm setup errors at the field edges, the junction target dose changed less than 5% and the dose sparing to organs at risk (OARs) was maintained. Film measurements confirmed the treatment planning results.

  7. Guidelines for delineation of lymphatic clinical target volumes for high conformal radiotherapy: head and neck region

    PubMed Central

    2011-01-01

    The success of radiotherapy depends on the accurate delineation of the clinical target volume. The delineation of the lymph node regions has most impact, especially for tumors in the head and neck region. The purpose of this article was the development an atlas for the delineation of the clinical target volume for patients, who should receive radiotherapy for a tumor of the head and neck region. Literature was reviewed for localisations of the adjacent lymph node regions and their lymph drain in dependence of the tumor entity. On this basis the lymph node regions were contoured on transversal CT slices. The probability for involvement was reviewed and a recommendation for the delineation of the CTV was generated. PMID:21854585

  8. SU-E-T-578: On Definition of Minimum and Maximum Dose for Target Volume

    SciTech Connect

    Gong, Y; Yu, J; Xiao, Y

    2015-06-15

    Purpose: This study aims to investigate the impact of different minimum and maximum dose definitions in radiotherapy treatment plan quality evaluation criteria by using tumor control probability (TCP) models. Methods: Dosimetric criteria used in RTOG 1308 protocol are used in the investigation. RTOG 1308 is a phase III randomized trial comparing overall survival after photon versus proton chemoradiotherapy for inoperable stage II-IIIB NSCLC. The prescription dose for planning target volume (PTV) is 70Gy. Maximum dose (Dmax) should not exceed 84Gy and minimum dose (Dmin) should not go below 59.5Gy in order for the plan to be “per protocol” (satisfactory).A mathematical model that simulates the characteristics of PTV dose volume histogram (DVH) curve with normalized volume is built. The Dmax and Dmin are noted as percentage volumes Dη% and D(100-δ)%, with η and d ranging from 0 to 3.5. The model includes three straight line sections and goes through four points: D95%= 70Gy, Dη%= 84Gy, D(100-δ)%= 59.5 Gy, and D100%= 0Gy. For each set of η and δ, the TCP value is calculated using the inhomogeneously irradiated tumor logistic model with D50= 74.5Gy and γ50=3.52. Results: TCP varies within 0.9% with η; and δ values between 0 and 1. With η and η varies between 0 and 2, TCP change was up to 2.4%. With η and δ variations from 0 to 3.5, maximum of 8.3% TCP difference is seen. Conclusion: When defined maximum and minimum volume varied more than 2%, significant TCP variations were seen. It is recommended less than 2% volume used in definition of Dmax or Dmin for target dosimetric evaluation criteria. This project was supported by NIH grants U10CA180868, U10CA180822, U24CA180803, U24CA12014 and PA CURE Grant.

  9. Comparison of various radiation therapy techniques in breast cancer where target volume includes mammaria interna region.

    PubMed

    Dogan, Mehmet Hakan; Zincircioglu, Seyit Burhanedtin; Zorlu, Faruk

    2009-01-01

    In breast cancer radiotherapy, the internal mammary lymphatic chain is treated in the target volume in a group of patients with high-risk criteria. Because of the variability of the anatomic region and structures in the irradiation field, there are a number of different techniques in breast radiotherapy. While irradiating the target volume, we also consider minimizing the dose to critical structures such as heart, lung, and contralateral breast tissue. In this study, we evaluated the dose distribution of different radiotherapy techniques in patients with left-sided breast cancer who had breast-conserving surgery. A three-dimensional computerized planning system (3DCPS) was used for each patient to compare wide-field, oblique photon-electron, and perpendicular photon-electron techniques in terms of dose homogeneities in the target volume; the doses received by the contralateral breast, heart, and lung; and the coverage of the internal mammary chain. Data from 3DCPS were controlled by the Rando-phantom and thermoluminescence dosimetry. Critical structures were irradiated with acceptable dose percentages in addition to the internal mammary chain with both wide-field and photon-electron techniques. We detected more frequent hot spots in the oblique photon-electron technique than in the other techniques, and this situation necessitated changing the junctions. The wide-field technique was easy to perform and exposed less radiation dose to the heart than photon-electron techniques. In conclusion, we suggest the use of the wide-field technique in breast irradiation when the internal mammary area is in the target volume.

  10. Postoperative radiation in esophageal squamous cell carcinoma and target volume delineation

    PubMed Central

    Zhu, Yingming; Li, Minghuan; Kong, Li; Yu, Jinming

    2016-01-01

    Esophageal cancer is the sixth leading cause of cancer death worldwide, and patients who are treated with surgery alone, without neoadjuvant therapies, experience frequent relapses. Whether postoperative therapies could reduce the recurrence or improve overall survival is still controversial for these patients. The purpose of our review is to figure out the value of postoperative adjuvant therapy and address the disputes about target volume delineation according to published data. Based on the evidence of increased morbidity and disadvantages on patient survival caused by postoperative chemotherapy or radiotherapy (RT) alone provided by studies in the early 1990s, the use of postoperative adjuvant therapies in cases of esophageal squamous cell carcinoma has diminished substantially and has been replaced gradually by neoadjuvant chemoradiation. With advances in surgery and RT, accumulating evidence has recently rekindled interest in the delivery of postoperative RT or chemoradiotherapy in patients with stage T3/T4 or N1 (lymph node positive) carcinomas after radical surgery. However, due to complications with the standard radiation field, a nonconforming modified field has been adopted in most studies. Therefore, we analyze different field applications and provide suggestions on the optimization of the radiation field based on the major sites of relapse and the surgical non-clearance area. For upper and middle thoracic esophageal carcinomas, the bilateral supraclavicular and superior mediastinal areas remain common sites of recurrence and should be encompassed within the clinical target volume. In contrast, a consensus has yet to be reached regarding lower thoracic esophageal carcinomas; the “standard” clinical target volume is still recommended. Further studies of larger sample sizes should focus on different recurrence patterns, categorized by tumor locations, refined classifications, and differing molecular biology, to provide more information on the

  11. Comparison of Various Radiation Therapy Techniques in Breast Cancer Where Target Volume Includes Mammaria Interna Region

    SciTech Connect

    Dogan, Mehmet Hakan; Zincircioglu, Seyit Burhanedtin Zorlu, Faruk

    2009-04-01

    In breast cancer radiotherapy, the internal mammary lymphatic chain is treated in the target volume in a group of patients with high-risk criteria. Because of the variability of the anatomic region and structures in the irradiation field, there are a number of different techniques in breast radiotherapy. While irradiating the target volume, we also consider minimizing the dose to critical structures such as heart, lung, and contralateral breast tissue. In this study, we evaluated the dose distribution of different radiotherapy techniques in patients with left-sided breast cancer who had breast-conserving surgery. A three-dimensional computerized planning system (3DCPS) was used for each patient to compare wide-field, oblique photon-electron, and perpendicular photon-electron techniques in terms of dose homogeneities in the target volume; the doses received by the contralateral breast, heart, and lung; and the coverage of the internal mammary chain. Data from 3DCPS were controlled by the Rando-phantom and thermoluminescence dosimetry. Critical structures were irradiated with acceptable dose percentages in addition to the internal mammary chain with both wide-field and photon-electron techniques. We detected more frequent hot spots in the oblique photon-electron technique than in the other techniques, and this situation necessitated changing the junctions. The wide-field technique was easy to perform and exposed less radiation dose to the heart than photon-electron techniques. In conclusion, we suggest the use of the wide-field technique in breast irradiation when the internal mammary area is in the target volume.

  12. Tumor target volume for focal therapy of prostate cancer-does multiparametric magnetic resonance imaging allow for a reliable estimation?

    PubMed

    Cornud, F; Khoury, Gaby; Bouazza, Naim; Beuvon, Frederic; Peyromaure, Michael; Flam, Thierry; Zerbib, Marc; Legmann, Paul; Delongchamps, Nicolas B

    2014-05-01

    We determined whether endorectal multiparametric magnetic resonance imaging at 1.5 Tesla could predict tumor target volume in the perspective of focal therapy of prostate cancer. A total of 84 consecutive patients underwent multiparametric magnetic resonance imaging before radical prostatectomy. The volume of each suspicious area detected on magnetic resonance imaging and of all surgical histological foci was determined by planimetry. We first used each magnetic resonance imaging sequence (T2-weighted, diffusion weighted and dynamic contrast enhanced) and then the sequence showing the largest tumor area (multiparametric volume). Finally, the largest area of any sequence was used to calculate a target volume according to the volume of a cylinder. Agreement between magnetic resonance imaging and pathological findings was assessed by linear regression and residual analysis. Histology revealed 99 significant tumors with a volume of greater than 0.2 cc and/or a Gleason score of greater than 6. Of the tumors 16 (16.2%) were undetected by multiparametric magnetic resonance imaging. Linear regression analysis showed that tumor volume estimated by T2-weighted or diffusion weighted imaging correlated significantly with pathological volume (r(2) = 0.82 and 0.83, respectively). Residuals from diffusion weighted imaging volume estimations did not significantly differ from 0. Nevertheless, diffusion weighted imaging underestimated pathological volume in 43 of 87 cases (49%) by a mean of 0.56 cc (range 0.005 to 2.84). Multiparametric and target volumes significantly overestimated pathological volume by a mean of 16% and 44% with underestimation in 28 (32%) and 15 cases (17%), respectively. Volume underestimation was significantly higher for tumor foci less than 0.5 cc. The percent of Gleason grade 4 did not influence tumor volume estimation. Magnetic resonance imaging can detect most significant tumors. However, delineating a target volume may require further adjustment before

  13. Multicenter evaluation of different target volume delineation concepts in pediatric Hodgkin's lymphoma. A case study.

    PubMed

    Lütgendorf-Caucig, C; Fotina, I; Gallop-Evans, E; Claude, L; Lindh, J; Pelz, T; Knäusl, B; Georg, D; Pötter, R; Dieckmann, K

    2012-11-01

    In pediatric Hodgkin's lymphoma (PHL) improvements in imaging and multiagent chemotherapy have allowed for a reduction in target volume. The involved-node (IN) concept is being tested in several treatment regimens for adult Hodgkin's lymphoma. So far there is no consensus on the definition of the IN. To improve the reproducibility of the IN, we tested a new involved-node-level (INL) concept, using defined anatomical boundaries as basis for target delineation. The aim was to evaluate the feasibility of IN and INL concepts for PHL in terms of interobserver variability. The INL concept was defined for the neck and mediastinum by the PHL Radiotherapy Group based on accepted concepts for solid tumors. Seven radiation oncologists from six European centers contoured neck and mediastinal clinical target volumes (CTVs) of 2 patients according to the IN and the new INL concepts. The median CTVs, coefficient of variation (COV), and general conformity index (CI) were assessed. The intraclass correlation coefficient (ICC) for reliability of delineations was calculated. All observers agreed that INL is a feasible and practicable delineation concept resulting in stronger interobserver concordance than the IN (mediastinum CI(INL) = 0.39 vs. CI(IN) = 0.28, neck left CI(INL) = 0.33; CI(IN) = 0.18; neck right CI(INL) = 0.24, CI(IN) = 0.14). The COV showed less dispersion and the ICC indicated higher reliability of contouring for INL (ICC(INL) = 0.62, p < 0.05) as for IN (ICC(IN) = 0.40, p < 0.05). INL is a practical and feasible alternative to IN resulting in more homogeneous target delineation, and it should be therefore considered as a future target volume concept in PHL.

  14. FDG-PET-based differential uptake volume histograms: a possible approach towards definition of biological target volumes.

    PubMed

    Devic, Slobodan; Mohammed, Huriyyah; Tomic, Nada; Aldelaijan, Saad; De Blois, François; Seuntjens, Jan; Lehnert, Shirley; Faria, Sergio

    2016-06-01

    Integration of fluorine-18 fludeoxyglucose ((18)F-FDG)-positron emission tomography (PET) functional data into conventional anatomically based gross tumour volume delineation may lead to optimization of dose to biological target volumes (BTV) in radiotherapy. We describe a method for defining tumour subvolumes using (18)F-FDG-PET data, based on the decomposition of differential uptake volume histograms (dUVHs). For 27 patients with histopathologically proven non-small-cell lung carcinoma (NSCLC), background uptake values were sampled within the healthy lung contralateral to a tumour in those image slices containing tumour and then scaled by the ratio of mass densities between the healthy lung and tumour. Signal-to-background (S/B) uptake values within volumes of interest encompassing the tumour were used to reconstruct the dUVHs. These were subsequently decomposed into the minimum number of analytical functions (in the form of differential uptake values as a function of S/B) that yielded acceptable net fits, as assessed by χ(2) values. Six subvolumes consistently emerged from the fitted dUVHs over the sampled volume of interest on PET images. Based on the assumption that each function used to decompose the dUVH may correspond to a single subvolume, the intersection between the two adjacent functions could be interpreted as a threshold value that differentiates them. Assuming that the first two subvolumes spread over the tumour boundary, we concentrated on four subvolumes with the highest uptake values, and their S/B thresholds [mean ± standard deviation (SD)] were 2.88 ± 0.98, 4.05 ± 1.55, 5.48 ± 2.06 and 7.34 ± 2.89 for adenocarcinoma, 3.01 ± 0.71, 4.40 ± 0.91, 5.99 ± 1.31 and 8.17 ± 2.42 for large-cell carcinoma and 4.54 ± 2.11, 6.46 ± 2.43, 8.87 ± 5.37 and 12.11 ± 7.28 for squamous cell carcinoma, respectively. (18)F-FDG-based PET data may potentially be used to identify BTV within the tumour in

  15. [Clinical to target volume margins determination in radiotherapy for anal cancers].

    PubMed

    Libois, V; Mahé, M-A; Rio, E; Maingon, P

    2016-10-01

    There are very few data on the expansion from the clinical target volume (CTV) to the planning target volume (PTV) in the anal cancer treatment. This article aims to collect the different elements needed for the construction of a PTV from scientific data based on a literature analysis. We reviewed the articles published in the medical literature from the last 20years. They concerned setup errors and internal organ mobility of the different volumes of patients treated by conformational radiotherapy and intensity-modulated radiotherapy (anal canal, meso-rectum, common, intern and extern, inguinal and pre-sacral lymph nodes). CTV to PTV margins admitted in the guidelines and atlas of consensus groups (SFRO, RTOG, AGITG) are from 0.7 to 1cm in all directions, based on expert's opinions but not on scientific data. There are no specific studies on the canal anal mobility. Most of the data are from other pelvis cancers (gynecologic, rectum and prostate). Setup errors can be reduced by daily imaging. Patient repositioning and immobilization modalities are mostly local habits rather than scientific consensus. A three-dimensional 1cm margin is generally admitted. Margins reduction must be careful and has to be assessed.

  16. Using Histopathology Breast Cancer Data to Reduce Clinical Target Volume Margins at Radiotherapy

    SciTech Connect

    Stroom, Joep Schlief, Angelique; Alderliesten, Tanja; Peterse, Hans; Bartelink, Harry; Gilhuijs, Kenneth

    2009-07-01

    Purpose: This study aimed to quantify the incidence and extension of microscopic disease around primary breast tumors in patients undergoing breast-conserving therapy (BCT), focusing on a potential application to reduce radiotherapy boost volumes. Methods and Materials: An extensive pathology tumor-distribution study was performed using 38 wide local excision specimens of BCT patients. Specimen orientation was recorded and microscopic findings reconstructed to assess the incidence of microscopic disease around the macroscopic tumor. A model of disease spread was built, showing probability of disease extension outside a treated volume (P{sub out,vol}). The model was applied in 10 new BCT patients. Taking asymmetry of tumor excision into account, new asymmetric margins for the clinical target volume of the boost (CTV{sub boost}) were evaluated that minimize the volume without increasing P{sub out,TTV} (TTV being total treated volume: V{sub surgery} + CTV{sub boost}). Potential reductions in CTV{sub boost} and TTV were evaluated. Results: Microscopic disease beyond the tumor boundary occurred isotropically at distances > 1 cm (intended surgical margin) and > 1.5 cm (intended TTV margin) in 53% and 36% of the excision specimens, respectively. In the 10 prospective patients, the average P{sub out,TTV} was, however, only 16% due to larger surgical margins than intended in some directions. Asymmetric CTV{sub boost} margins reduced the CTV{sub boost} and TTV by 27% (20 cc) and 12% (21 cc) on average, without compromising tumor coverage. Conclusions: Microscopic disease extension may occur beyond the current CTV{sub boost} in approximately one sixth of patients. An asymmetric CTV{sub boost} that corrects for asymmetry of the surgical excision has the potential to reduce boost volumes while maintaining tumor coverage.

  17. Target Volume Delineation for Partial Breast Radiotherapy Planning: Clinical Characteristics Associated with Low Interobserver Concordance

    SciTech Connect

    Petersen, Ross P.; Truong, Pauline T. Kader, Hosam A.; Berthelet, Eric; Lee, Junella C.; Hilts, Michelle L.; Kader, Adam S.; Beckham, Wayne A.; Olivotto, Ivo A.

    2007-09-01

    Purpose: To examine variability in target volume delineation for partial breast radiotherapy planning and evaluate characteristics associated with low interobserver concordance. Methods and Materials: Thirty patients who underwent planning CT for adjuvant breast radiotherapy formed the study cohort. Using a standardized scale to score seroma clarity and consensus contouring guidelines, three radiation oncologists independently graded seroma clarity and delineated seroma volumes for each case. Seroma geometric center coordinates, maximum diameters in three axes, and volumes were recorded. Conformity index (CI), the ratio of overlapping volume and encompassing delineated volume, was calculated for each case. Cases with CI {<=}0.50 were analyzed to identify features associated with low concordance. Results: The median time from surgery to CT was 42.5 days. For geometric center coordinates, variations from the mean were 0.5-1.1 mm and standard deviations (SDs) were 0.5-1.8 mm. For maximum seroma dimensions, variations from the mean and SDs were predominantly <5 mm, with the largest SDs observed in the medial-lateral axis. The mean CI was 0.61 (range, 0.27-0.84). Five cases had CI {<=}0.50. Conformity index was significantly associated with seroma clarity (p < 0.001) and seroma volume (p < 0.002). Features associated with reduced concordance included tissue stranding from the surgical cavity, proximity to muscle, dense breast parenchyma, and benign calcifications that may be mistaken for surgical clips. Conclusion: Variability in seroma contouring occurred in three dimensions, with the largest variations in the medial-lateral axis. Awareness of clinical features associated with reduced concordance may be applied toward training staff and refining contouring guidelines for partial breast radiotherapy trials.

  18. Retroperitoneal Sarcoma Target Volume and Organ at Risk Contour Delineation Agreement Among NRG Sarcoma Radiation Oncologists

    SciTech Connect

    Baldini, Elizabeth H.; Abrams, Ross A.; Bosch, Walter; Roberge, David; Haas, Rick L.M.; Catton, Charles N.; Indelicato, Daniel J.; Olsen, Jeffrey R.; Deville, Curtiland; Chen, Yen-Lin; Finkelstein, Steven E.; DeLaney, Thomas F.; Wang, Dian

    2015-08-01

    Purpose: The purpose of this study was to evaluate the variability in target volume and organ at risk (OAR) contour delineation for retroperitoneal sarcoma (RPS) among 12 sarcoma radiation oncologists. Methods and Materials: Radiation planning computed tomography (CT) scans for 2 cases of RPS were distributed among 12 sarcoma radiation oncologists with instructions for contouring gross tumor volume (GTV), clinical target volume (CTV), high-risk CTV (HR CTV: area judged to be at high risk of resulting in positive margins after resection), and OARs: bowel bag, small bowel, colon, stomach, and duodenum. Analysis of contour agreement was performed using the simultaneous truth and performance level estimation (STAPLE) algorithm and kappa statistics. Results: Ten radiation oncologists contoured both RPS cases, 1 contoured only RPS1, and 1 contoured only RPS2 such that each case was contoured by 11 radiation oncologists. The first case (RPS 1) was a patient with a de-differentiated (DD) liposarcoma (LPS) with a predominant well-differentiated (WD) component, and the second case (RPS 2) was a patient with DD LPS made up almost entirely of a DD component. Contouring agreement for GTV and CTV contours was high. However, the agreement for HR CTVs was only moderate. For OARs, agreement for stomach, bowel bag, small bowel, and colon was high, but agreement for duodenum (distorted by tumor in one of these cases) was fair to moderate. Conclusions: For preoperative treatment of RPS, sarcoma radiation oncologists contoured GTV, CTV, and most OARs with a high level of agreement. HR CTV contours were more variable. Further clarification of this volume with the help of sarcoma surgical oncologists is necessary to reach consensus. More attention to delineation of the duodenum is also needed.

  19. Variation of clinical target volume definition in three-dimensional conformal radiation therapy for prostate cancer.

    PubMed

    Valicenti, R K; Sweet, J W; Hauck, W W; Hudes, R S; Lee, T; Dicker, A P; Waterman, F M; Anne, P R; Corn, B W; Galvin, J M

    1999-07-01

    Currently, three-dimensional conformal radiation therapy (3D-CRT) planning relies on the interpretation of computed tomography (CT) axial images for defining the clinical target volume (CTV). This study investigates the variation among multiple observers to define the CTV used in 3D-CRT for prostate cancer. Seven observers independently delineated the CTVs (prostate +/- seminal vesicles [SV]) from the CT simulation data of 10 prostate cancer patients undergoing 3D-CRT. Six patients underwent CT simulation without the use of contrast material and serve as a control group. The other 4 had urethral and bladder opacification with contrast medium. To determine interobserver variation, we evaluated the derived volume, the maximum dimensions, and the isocenter for each examination of CTV. We assessed the reliability in the CTVs among the observers by correlating the variation for each class of measurements. This was estimated by intraclass correlation coefficient (ICC), with 1.00 defining absolute correlation. For the prostate volumes, the ICC was 0.80 (95% confidence interval [CI]: 0.56-0.96). This changed to 0.92 (95% CI: 0.75-0.99) with the use of contrast material. Similarly, the maximal prostatic dimensions were reliable and improved. There was poor agreement in defining the SV. For this structure, the ICC never exceeded 0.28. The reliability of the isocenter was excellent, with the ICC exceeding 0.83 and 0.90 for the prostate +/- SV, respectively. In 3D-CRT for prostate cancer, there was excellent agreement among multiple observers to define the prostate target volume but poor agreement to define the SV. The use of urethral and bladder contrast improved the reliability of localizing the prostate. For all CTVs, the isocenter was very reliable and should be used to compare the variation in 3D dosimetry among multiple observers.

  20. Potential implications of the bystander effect on TCP and EUD when considering target volume dose heterogeneity.

    PubMed

    Balderson, Michael J; Kirkby, Charles

    2015-01-01

    In light of in vitro evidence suggesting that radiation-induced bystander effects may enhance non-local cell killing, there is potential for impact on radiotherapy treatment planning paradigms such as the goal of delivering a uniform dose throughout the clinical target volume (CTV). This work applies a bystander effect model to calculate equivalent uniform dose (EUD) and tumor control probability (TCP) for external beam prostate treatment and compares the results with a more common model where local response is dictated exclusively by local absorbed dose. The broad assumptions applied in the bystander effect model are intended to place an upper limit on the extent of the results in a clinical context. EUD and TCP of a prostate cancer target volume under conditions of increasing dose heterogeneity were calculated using two models: One incorporating bystander effects derived from previously published in vitro bystander data ( McMahon et al. 2012 , 2013a); and one using a common linear-quadratic (LQ) response that relies exclusively on local absorbed dose. Dose through the CTV was modelled as a normal distribution, where the degree of heterogeneity was then dictated by changing the standard deviation (SD). Also, a representative clinical dose distribution was examined as cold (low dose) sub-volumes were systematically introduced. The bystander model suggests a moderate degree of dose heterogeneity throughout a target volume will yield as good or better outcome compared to a uniform dose in terms of EUD and TCP. For a typical intermediate risk prostate prescription of 78 Gy over 39 fractions maxima in EUD and TCP as a function of increasing SD occurred at SD ∼ 5 Gy. The plots only dropped below the uniform dose values for SD ∼ 10 Gy, almost 13% of the prescribed dose. Small, but potentially significant differences in the outcome metrics between the models were identified in the clinically-derived dose distribution as cold sub-volumes were introduced. In terms of

  1. Prostate bed target interfractional motion using RTOG consensus definitions and daily CT on rails : Does target motion differ between superior and inferior portions of the clinical target volume?

    PubMed

    Verma, Vivek; Chen, Shifeng; Zhou, Sumin; Enke, Charles A; Wahl, Andrew O

    2017-01-01

    Using high-quality CT-on-rails imaging, the daily motion of the prostate bed clinical target volume (PB-CTV) based on consensus Radiation Therapy Oncology Group (RTOG) definitions (instead of surgical clips/fiducials) was studied. It was assessed whether PB motion in the superior portion of PB-CTV (SUP-CTV) differed from the inferior PB-CTV (INF-CTV). Eight pT2-3bN0-1M0 patients underwent postprostatectomy intensity-modulated radiotherapy, totaling 300 fractions. INF-CTV and SUP-CTV were defined as PB-CTV located inferior and superior to the superior border of the pubic symphysis, respectively. Daily pretreatment CT-on-rails images were compared to the planning CT in the left-right (LR), superoinferior (SI), and anteroposterior (AP) directions. Two parameters were defined: "total PB-CTV motion" represented total shifts from skin tattoos to RTOG-defined anatomic areas; "PB-CTV target motion" (performed for both SUP-CTV and INF-CTV) represented shifts from bone to RTOG-defined anatomic areas (i. e., subtracting shifts from skin tattoos to bone). Mean (± standard deviation, SD) total PB-CTV motion was -1.5 (± 6.0), 1.3 (± 4.5), and 3.7 (± 5.7) mm in LR, SI, and AP directions, respectively. Mean (± SD) PB-CTV target motion was 0.2 (±1.4), 0.3 (±2.4), and 0 (±3.1) mm in the LR, SI, and AP directions, respectively. Mean (± SD) INF-CTV target motion was 0.1 (± 2.8), 0.5 (± 2.2), and 0.2 (± 2.5) mm, and SUP-CTV target motion was 0.3 (± 1.8), 0.5 (± 2.3), and 0 (± 5.0) mm in LR, SI, and AP directions, respectively. No statistically significant differences between INF-CTV and SUP-CTV motion were present in any direction. There are no statistically apparent motion differences between SUP-CTV and INF-CTV. Current uniform planning target volume (PTV) margins are adequate to cover both portions of the CTV.

  2. 3D coronary MR angiography at 1.5 T: Volume-targeted versus whole-heart acquisition.

    PubMed

    Jin, Hang; Zeng, Meng-Su; Ge, Mei-Ying; Yun, Hong; Yang, Shan

    2013-09-01

    To compare volume-targeted acquisition with whole-heart acquisition in 1.5-T free-breathing 3D coronary magnetic resonance angiography (MRA) with parallel imaging. The major coronary arteries were imaged in 36 subjects using the whole-heart and volume-targeted acquisitions with comparable imaging parameters. The quantitative and semiquantitative data derived from these two acquisition methods were analyzed statistically, with P < 0.05 considered significant. Both the right coronary artery (RCA) / left circumflex artery (LCX)- and the left main (LM) / left anterior descending (LAD)-targeted acquisitions had similar results in navigator efficiencies and apparent signal-to-noise ratio (SNR) in comparison with whole-heart acquisition. Apparent contrast-to-noise ratio (CNR) of the volume-targeted imaging was significantly higher than that of the whole-heart imaging. The imaging time required for a whole-heart scan was significantly longer than each of the RCA/LCX- and LM/LAD-targeted acquisitions. However, the sum of scanning times derived from volume-targeted imaging was significantly longer than that of whole-heart acquisition. Both RCA/LCX- and LM/LAD-targeted acquisition yield higher vessel sharpness and overall image quality in comparison with whole-heart acquisition. The lengths of the major coronary arteries were not significantly different for the whole-heart and volume-targeted approaches. The whole-heart method was obviously superior to the volume-targeted method in terms of visualization of the posterior descending artery. For current 1.5-T navigator coronary MRA, volume-targeted and whole-heart acquisitions have their own advantages and the choice of methods may vary in accordance with the different aims of clinical practice. Copyright © 2013 Wiley Periodicals, Inc., a Wiley company.

  3. Does targeted pre-load optimisation by stroke volume variation attenuate a reduction in cardiac output in the prone position.

    PubMed

    Wu, C-Y; Lee, T-S; Chan, K-C; Jeng, C-S; Cheng, Y-J

    2012-07-01

    The prone position can reduce cardiac output by up to 25% due to reduced preload. We hypothesised that preload optimisation targeted to stroke volume variation before turning prone might alleviate this. A supine threshold stroke volume variation of 14% in a preliminary study identified patients whose cardiac outputs would decline when turned prone. In 45 patients, cardiac output declined only in the group whose supine stroke volume variation was high (mean (SD) 5.1 (2.0) to 3.9 (1.9) l.min(-1) ; p < 0.001), but not in patients in whom it was low, or in those in whom stroke volume variation was high, but who received volume preload (p = 0.525 and 0.941, respectively). We conclude that targeted preload optimisation using a supine stroke volume variation value < 14% is effective in preventing falls in cardiac output induced by the prone position.

  4. [Comparison of the volume and localization of internal gross target volume and planning target volume delineated by clips and seroma based on 4D-CT scan for external-beam partial breast irradiation after breast conserving surgery].

    PubMed

    Ding, Yun; Li, Jianbin; Wang, Wei; Wang, Suzhen; Wang, Jinzhi; Ma, Zhifang

    2014-10-01

    To explore the differences in volume and localization of the internal gross target volume and planning target volume delineated by clips and/or seroma based on four-dimensional computed tomography (4D-CT) during free-breathing in breast cancer patients after breast conserving surgery. Fifteen breast cancer patients after breast-conserving surgery (BCS) were recruited for external-beam partial breast irradiation (EB-PBI). On the ten sets CT images, the gross tumor volumes (GTV) formed by the clips, the seroma, and both the clips and seroma were delineated and defined as GTVc, GTVs and GTVc+s, respectively. Ten GTVc, GTVs and GTVc+s on the ten sets CT images produced the IGTVc, IGTVs, IGTVc+s. The PTVc, PTVs, PTVc+s were created by adding 15 mm to the IGTVc, IGTVs, IGTVc+s, respectively. The IGTV and PTV volume and distance between the centers of IGTVc, IGTVs, IGTVc+s and PTVc, PTVs, PTVc+s were all recorded. Conformity index (CI) and degree of inclusion (DI) were calculated for IGTV/IGTV and PTV/PTV, respectively. The volume of IGTVc+s[(35.73 ± 19.77) cm³] was significantly larger than the IGTVc [(28.35 ± 17.54) cm³] and IGTVs [(24.19 ± 21.53) cm³] (P < 0.05), and the volume of PTVc+s [(191.59 ± 69.74) cm³] was significantly larger than that of the PTVc [(161.53 ± 61.07) cm³] and PTVs [(148.98 ± 62.22)cm³] (P < 0.05). There were significant differences between the DIs of IGTVc in IGTVc+s and IGTVc+s in IGTVc, the DIs of IGTVs in IGTVc+s and IGTVc+s in IGTVs, the DIs of PTVc in PTVc+s and PTVc+s in PTVc, and the DIs of PTVs vs. PTVc+s and PTVc+s in PTVs (P < 0.05 for all). The CI of IGTVc/IGTVc+s (0.63 ± 0.14) and the CI of IGTVs/IGTVc+s (0.54 ± 0.17) were significant larger than that of the CI of IGTVc/IGTVs (0.40 ± 0.14)(P < 0.05). There were non-significant differences among the CI of PTVc/PTVs, PTVc/PTVc+s and PTVs/PTVc+s (0.73 ± 0.12, 0.78 ± 0.13 vs. 0.75 ± 0.17). The DIs and CIs of IGTV/IGTV and PTV/PTV were negatively correlated with their

  5. Motion mitigation in intensity modulated particle therapy by internal target volumes covering range changes.

    PubMed

    Graeff, Christian; Durante, Marco; Bert, Christoph

    2012-10-01

    Particle therapy offers benefits over conventional photon therapy but also introduces sensitivity to changes in the water-equivalent path length (WEPL) in case of target motion, e.g., breathing. Target motion can be addressed by the internal target volume (ITV) approach, defined as the CTV plus target movement. In photon therapy, the ITV can be constructed as the geometric union of CTVs in all motion states (GEO-ITV) of a 4D-CT, but this does not account for WEPL-changes. An ITV including WEPL-changes can be defined as the union of all CTVs transformed to a WEPL-equivalent axis along beam's eye view. The resulting WEPL-ITV is field-specific and thus unsuitable for intensity modulated particle therapy (IMPT). The purpose of this study was an IMPT-compatible ITV by splitting geometrical motion and field-specific WEPL changes, following ICRU 78 recommendations. For all fields, the GEO-ITV was used as a common target. This identical geometry for all fields was mapped to an enlarged WEPL extent with a field-specific transformation. As the dose distribution is determined by the WEPL, this is sufficient to achieve equivalent dose coverage as for a geometrically enlarged target volume. The WEPL enlargement is only visible to the specific field and therefore does not increase the target volume of other fields. This avoids unnecessary lateral field extensions, reducing the dose to normal tissue. Homogeneous dose coverage in IMPT is achieved only if the inhomogeneous doses from the individual fields match up during delivery. As the course of the WEPL within each motion phase differs, this cannot be guaranteed by optimizing the fields only in the reference phase. The WEPL-ITV for the reference phase can be amended by CTVs from a subset of motion phases (4D-WEPL-ITV). Here, end-exhale as the reference phase was combined with end-inhale to cover the whole motion range. The GEO-ITV, WEPL-ITV, and 4D-WEPL-ITV were applied in an IMPT simulation of a lung cancer patient case using a

  6. Using four-dimensional computed tomography images to optimize the internal target volume when using volume-modulated arc therapy to treat moving targets.

    PubMed

    Yakoumakis, Nikolaos; Winey, Brian; Killoran, Joseph; Mayo, Charles; Niedermayr, Thomas; Panayiotakis, George; Lingos, Tania; Court, Laurence

    2012-11-08

    In this work we used 4D dose calculations, which include the effects of shape deformations, to investigate an alternative approach to creating the ITV. We hypothesized that instead of needing images from all the breathing phases in the 4D CT dataset to create the outer envelope used for treatment planning, it is possible to exclude images from the phases closest to the inhale phase. We used 4D CT images from 10 patients with lung cancer. For each patient, we drew a gross tumor volume on the exhale-phase image and propagated this to the images from other phases in the 4D CT dataset using commercial image registration software. We created four different ITVs using the N phases closest to the exhale phase (where N = 10, 8, 7, 6). For each ITV contour, we created a volume-modulated arc therapy plan on the exhale-phase CT and normalized it so that the prescribed dose covered at least 95% of the ITV. Each plan was applied to CT images from each CT phase (phases 1-10), and the calculated doses were then mapped to the exhale phase using deformable registration. The effect of the motion was quantified using the dose to 95% of the target on the exhale phase (D95) and tumor control probability. For the three-dimensional and 4D dose calculations of the plan where N = 10, differences in the D95 value varied from 3% to 14%, with an average difference of 7%. For 9 of the 10 patients, the reduction in D95 was less than 5% if eight phases were used to create the ITV. For three of the 10 patients, the reduction in the D95 was less than 5% if seven phases were used to create the ITV. We were unsuccessful in creating a general rule that could be used to create the ITV. Some reduction (8/10 phases) was possible for most, but not all, of the patients, and the ITV reduction was small.

  7. Data fusion for planning target volume and isodose prediction in prostate brachytherapy

    NASA Astrophysics Data System (ADS)

    Nouranian, Saman; Ramezani, Mahdi; Mahdavi, S. Sara; Spadinger, Ingrid; Morris, William J.; Salcudean, Septimiu E.; Abolmaesumi, Purang

    2015-03-01

    In low-dose prostate brachytherapy treatment, a large number of radioactive seeds is implanted in and adjacent to the prostate gland. Planning of this treatment involves the determination of a Planning Target Volume (PTV), followed by defining the optimal number of seeds, needles and their coordinates for implantation. The two major planning tasks, i.e. PTV determination and seed definition, are associated with inter- and intra-expert variability. Moreover, since these two steps are performed in sequence, the variability is accumulated in the overall treatment plan. In this paper, we introduce a model based on a data fusion technique that enables joint determination of PTV and the minimum Prescribed Isodose (mPD) map. The model captures the correlation between different information modalities consisting of transrectal ultrasound (TRUS) volumes, PTV and isodose contours. We take advantage of joint Independent Component Analysis (jICA) as a linear decomposition technique to obtain a set of joint components that optimally describe such correlation. We perform a component stability analysis to generate a model with stable parameters that predicts the PTV and isodose contours solely based on a new patient TRUS volume. We propose a framework for both modeling and prediction processes and evaluate it on a dataset of 60 brachytherapy treatment records. We show PTV prediction error of 10:02+/-4:5% and the V100 isodose overlap of 97+/-3:55% with respect to the clinical gold standard.

  8. Comparative Study With New Accuracy Metrics for Target Volume Contouring in PET Image Guided Radiation Therapy

    PubMed Central

    Shepherd, T; Teras, M; Beichel, RR; Boellaard, R; Bruynooghe, M; Dicken, V; Gooding, MJ; Julyan, PJ; Lee, JA; Lefèvre, S; Mix, M; Naranjo, V; Wu, X; Zaidi, H; Zeng, Z; Minn, H

    2017-01-01

    The impact of positron emission tomography (PET) on radiation therapy is held back by poor methods of defining functional volumes of interest. Many new software tools are being proposed for contouring target volumes but the different approaches are not adequately compared and their accuracy is poorly evaluated due to the ill-definition of ground truth. This paper compares the largest cohort to date of established, emerging and proposed PET contouring methods, in terms of accuracy and variability. We emphasize spatial accuracy and present a new metric that addresses the lack of unique ground truth. Thirty methods are used at 13 different institutions to contour functional volumes of interest in clinical PET/CT and a custom-built PET phantom representing typical problems in image guided radiotherapy. Contouring methods are grouped according to algorithmic type, level of interactivity and how they exploit structural information in hybrid images. Experiments reveal benefits of high levels of user interaction, as well as simultaneous visualization of CT images and PET gradients to guide interactive procedures. Method-wise evaluation identifies the danger of over-automation and the value of prior knowledge built into an algorithm. PMID:22692898

  9. Accuracy estimation for projection-to-volume targeting during rotational therapy: a feasibility study.

    PubMed

    Long, Yong; Fessler, Jeffrey A; Balter, James M

    2010-06-01

    Estimating motion and deformation parameters from a series of projection radiographs acquired during arc therapy using a reference CT volume has become a promising technique for targeting treatment. The purpose of this work is to investigate the influence of rotational arc length on maximum achievable accuracy of motion estimation. The projection-to-volume alignment procedure used a nonrigid model to describe motion in thorax area, a cost function consisting of a least-squared error metric and a simple regularizer that encourages local invertibility, and a four-level multiresolution scheme with a conjugate gradient method to optimize the cost function. The authors tested both small and large scale deformations typically found in the thorax of a radiotherapy patient at different breathing states and limited-angle scans of six angular widths (12 degrees, 18 degrees, 24 degrees, 36 degrees, 60 degrees, and 90 degrees) centered at three angles (0 degrees, 45 degrees, and 90 degrees). The experiments illustrate the potential accuracy of limited-angle projection-to-volume alignment. Registration accuracy can be sensitive to angular center, tends to be lower along direction of the projection set, and tends to decrease away from the rotation center. The studies of small as well as large but realistically scaled deformations show similar dependencies. These trends appear to have fairly low sensitivity to quantum noise effects. There is potentially sufficient information present in a small spread of projections to monitor the configuration of reasonably high contrast tumors without implanted markers.

  10. Influence of FDG-PET on primary nodal target volume definition for head and neck carcinomas.

    PubMed

    van Egmond, Sylvia L; Piscaer, Vera; Janssen, Luuk M; Stegeman, Inge; Hobbelink, Monique G; Grolman, Wilko; Terhaard, Chris H

    The role of 2-[(18)F]-fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in routine diagnostic staging remains controversial. In case of discordance between FDG-PET and CT, a compromise has to be made between the risk of false positive FDG-PET and the risk of delaying appropriate salvage intervention. Second, with intensity modulated radiation therapy (IMRT), smaller radiation fields allow tissue sparing, but could also lead to more marginal failures. We retrospectively studied 283 patients with head and neck carcinoma scheduled for radiotherapy between 2002 and 2010. We analyzed the influence of FDG-PET/CT versus CT alone on defining nodal target volume definition and evaluated its long-term clinical results. Second, the location of nodal recurrences was related to the radiation regional dose distribution. In 92 patients, CT and FDG-PET, performed in mold, showed discordant results. In 33%, nodal staging was altered by FDG-PET. In 24%, FDG-PET also led to an alteration in nodal treatment, including a nodal upstage of 18% and downstage of 6%. In eight of these 92 patients, a regional recurrence occurred. Only two patients had a recurrence in the discordant node on FDG-PET and CT and both received a boost (high dose radiation). These results support the complementary value of FDG-PET/CT compared to CT alone in defining nodal target volume definition for radiotherapy of head and neck cancer.

  11. Delineation of Internal Mammary Nodal Target Volumes in Breast Cancer Radiation Therapy.

    PubMed

    Jethwa, Krishan R; Kahila, Mohamed M; Hunt, Katie N; Brown, Lindsay C; Corbin, Kimberly S; Park, Sean S; Yan, Elizabeth S; Boughey, Judy C; Mutter, Robert W

    2017-03-15

    The optimal clinical target volume for internal mammary (IM) node irradiation is uncertain in an era of increasingly conformal volume-based treatment planning for breast cancer. We mapped the location of gross internal mammary lymph node (IMN) metastases to identify areas at highest risk of harboring occult disease. Patients with axial imaging of IMN disease were identified from a breast cancer registry. The IMN location was transferred onto the corresponding anatomic position on representative axial computed tomography images of a patient in the treatment position and compared with consensus group guidelines of IMN target delineation. The IMN location in 67 patients with 130 IMN metastases was mapped. The location was in the first 3 intercostal spaces in 102 of 130 nodal metastases (78%), whereas 18 of 130 IMNs (14%) were located caudal to the third intercostal space and 10 of 130 IMNs (8%) were located cranial to the first intercostal space. Of the 102 nodal metastases within the first 3 intercostal spaces, 54 (53%) were located within the Radiation Therapy Oncology Group consensus volume. Relative to the IM vessels, 19 nodal metastases (19%) were located medially with a mean distance of 2.2 mm (SD, 2.9 mm) whereas 29 (28%) were located laterally with a mean distance of 3.6 mm (SD, 2.5 mm). Ninety percent of lymph nodes within the first 3 intercostal spaces would have been encompassed within a 4-mm medial and lateral expansion on the IM vessels. In women with indications for elective IMN irradiation, a 4-mm medial and lateral expansion on the IM vessels may be appropriate. In women with known IMN involvement, cranial extension to the confluence of the IM vein with the brachiocephalic vein with or without caudal extension to the fourth or fifth interspace may be considered provided that normal tissue constraints are met. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Routine gastric residual volume measurement and energy target achievement in the PICU: a comparison study.

    PubMed

    Tume, Lyvonne N; Bickerdike, Anna; Latten, Lynne; Davies, Simon; Lefèvre, Madeleine H; Nicolas, Gaëlle W; Valla, Frédéric V

    2017-09-18

    Critically ill children frequently fail to achieve adequate energy intake, and some care practices, such as the measurement of gastric residual volume (GRV), may contribute to this problem. We compared outcomes in two similar European Paediatric Intensive Care Units (PICUs): one which routinely measures GRV (PICU-GRV) to one unit that does not (PICU-noGRV). An observational pilot comparison study was undertaken. Eighty-seven children were included in the study, 42 (PICU-GRV) and 45 (PICU-noGRV). There were no significant differences in the percentage of energy targets achieved in the first 4 days of PICU admission although PICU-noGRV showed more consistent delivery of median (and IQR) energy targets and less under and over feeding for PICU-GRV and PICU-noGRV: day 1 37 (14-72) vs 44 (0-100), day 2 97 (53-126) vs 100 (100-100), day 3 84 (45-112) vs 100 (100-100) and day 4 101 (63-124) vs 100 (100-100). The incidence of vomiting was higher in PICU-GRV. No necrotising enterocolitis was confirmed in either unit, and ventilator-acquired pneumonia rates were not significantly different (7.01 vs 12 5.31 per 1000 ventilator days; p = 0.70) between PICU-GRV and PICU-noGRV units. The practice of routine gastric residual measurement did not significantly impair energy targets in the first 4 days of PICU admission. However, not measuring GRV did not increase vomiting, ventilator-acquired pneumonia or necrotising enterocolitis, which is the main reason clinicians cite for measuring GRV. What is known: • The practice of routinely measuring gastric residual volume is widespread in critical care units • This practice is increasingly being questioned in critically ill patients, both as a practice that increases • The likelihood of delivering inadequate enteral nutrition amounts and as a tool to assess feeding tolerance What is new: • Not routinely measuring gastric residual volume did not increase adverse events of ventilator acquired pneumonia, necrotising enterocolitis

  13. Relapse patterns after radiochemotherapy of glioblastoma with FET PET-guided boost irradiation and simulation to optimize radiation target volume.

    PubMed

    Piroth, Marc D; Galldiks, Norbert; Pinkawa, Michael; Holy, Richard; Stoffels, Gabriele; Ermert, Johannes; Mottaghy, Felix M; Shah, N Jon; Langen, Karl-Josef; Eble, Michael J

    2016-06-24

    O-(2-18 F-fluoroethyl)-L-tyrosine-(FET)-PET may be helpful to improve the definition of radiation target volumes in glioblastomas compared with MRI. We analyzed the relapse patterns in FET-PET after a FET- and MRI-based integrated-boost intensity-modulated radiotherapy (IMRT) of glioblastomas to perform an optimized target volume definition. A relapse pattern analysis was performed in 13 glioblastoma patients treated with radiochemotherapy within a prospective phase-II-study between 2008 and 2009. Radiotherapy was performed as an integrated-boost intensity-modulated radiotherapy (IB-IMRT). The prescribed dose was 72 Gy for the boost target volume, based on baseline FET-PET (FET-1) and 60 Gy for the MRI-based (MRI-1) standard target volume. The single doses were 2.4 and 2.0 Gy, respectively. Location and volume of recurrent tumors in FET-2 and MRI-2 were analyzed related to initial tumor, detected in baseline FET-1. Variable target volumes were created theoretically based on FET-1 to optimally cover recurrent tumor. The tumor volume overlap in FET and MRI was poor both at baseline (median 12 %; range 0-32) and at time of recurrence (13 %; 0-100). Recurrent tumor volume in FET-2 was localized to 39 % (12-91) in the initial tumor volume (FET-1). Over the time a shrinking (mean 12 (5-26) ml) and shifting (mean 6 (1-10 mm) of the resection cavity was seen. A simulated target volume based on active tumor in FET-1 with an additional safety margin of 7 mm around the FET-1 volume covered recurrent FET tumor volume (FET-2) significantly better than a corresponding target volume based on contrast enhancement in MRI-1 with a same safety margin of 7 mm (100 % (54-100) versus 85 % (0-100); p < 0.01). A simulated planning target volume (PTV), based on FET-1 and additional 7 mm margin plus 5 mm margin for setup-uncertainties was significantly smaller than the conventional, MR-based PTV applied in this study (median 160 (112-297) ml versus 231 (117-386) ml, p < 0.001). In this

  14. The role of delineation education programs for improving interobserver variability in target volume delineation in gastric cancer.

    PubMed

    Onal, Cem; Cengiz, Mustafa; Guler, Ozan C; Dolek, Yemliha; Ozkok, Serdar

    2017-05-01

    To assess whether delineation courses for radiation oncologists improve interobserver variability in target volume delineation for post-operative gastric cancer radiotherapy planning. 29 radiation oncologists delineated target volumes in a gastric cancer patient. An experienced radiation oncologist lectured about delineation based on contouring atlas and delineation recommendations. After the course, the radiation oncologists, blinded to the previous delineation, provided delineation for the same patient. The difference between delineated volumes and reference volumes for pre- and post-course clinical target volume (CTV) were 19.8% (-42.4 to 70.6%) and 12.3% (-12.0 to 27.3%) (p = 0.26), respectively. The planning target volume (PTV) differences pre- and post-course according to the reference volume were 20.5% (-40.7 to 93.7%) and 13.1% (-10.6 to 29.5%) (p = 0.30), respectively. The concordance volumes between the pre- and post-course CTVs and PTVs were 467.1 ± 89.2 vs 597.7 ± 54.6 cm(3) (p < 0.001) and 738.6 ± 135.1 vs 893.2 ± 144.6 cm(3) (p < 0.001), respectively. Minimum and maximum observer variations were seen at the cranial part and splenic hilus and at the caudal part of the CTV. The kappa indices compared with the reference contouring at pre- and post-course delineations were 0.68 and 0.82, respectively. The delineation course improved interobserver variability for gastric cancer. However, impact of target volume changes on toxicity and local control should be evaluated for further studies. Advances in knowledge: This study demonstrated that a delineation course based on current recommendations helped physicians delineate smaller and more homogeneous target volumes. Better target volume delineation allows proper target volume irradiation and preventing unnecessary normal tissue irradiation.

  15. Dosimetric Advantages of Midventilation Compared With Internal Target Volume for Radiation Therapy of Pancreatic Cancer.

    PubMed

    Lens, Eelco; van der Horst, Astrid; Versteijne, Eva; van Tienhoven, Geertjan; Bel, Arjan

    2015-07-01

    The midventilation (midV) approach can be used to take respiratory-induced pancreatic tumor motion into account during radiation therapy. In this study, the dosimetric consequences for organs at risk and tumor coverage of using a midV approach compared with using an internal target volume (ITV) were investigated. For each of the 18 patients, 2 treatment plans (25 × 2.0 Gy) were created, 1 using an ITV and 1 using a midV approach. The midV dose distribution was blurred using the respiratory-induced motion from 4-dimensional computed tomography. The resulting planning target volume (PTV) coverage for this blurred dose distribution was analyzed; PTV coverage was required to be at least V95% >98%. In addition, the change in PTV size and the changes in V10Gy, V20Gy, V30Gy, V40Gy, Dmean and D2cc for the stomach and for the duodenum were analyzed; differences were tested for significance using the Wilcoxon signed-rank test. Using a midV approach resulted in sufficient target coverage. A highly significant PTV size reduction of 13.9% (P<.001) was observed. Also, all dose parameters for the stomach and duodenum, except the D2cc of the duodenum, improved significantly (P≤.002). By using the midV approach to account for respiratory-induced tumor motion, a significant PTV reduction and significant dose reductions to the stomach and to the duodenum can be achieved when irradiating pancreatic tumors. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Dosimetric Advantages of Midventilation Compared With Internal Target Volume for Radiation Therapy of Pancreatic Cancer

    SciTech Connect

    Lens, Eelco Horst, Astrid van der; Versteijne, Eva; Tienhoven, Geertjan van; Bel, Arjan

    2015-07-01

    Purpose: The midventilation (midV) approach can be used to take respiratory-induced pancreatic tumor motion into account during radiation therapy. In this study, the dosimetric consequences for organs at risk and tumor coverage of using a midV approach compared with using an internal target volume (ITV) were investigated. Methods and Materials: For each of the 18 patients, 2 treatment plans (25 × 2.0 Gy) were created, 1 using an ITV and 1 using a midV approach. The midV dose distribution was blurred using the respiratory-induced motion from 4-dimensional computed tomography. The resulting planning target volume (PTV) coverage for this blurred dose distribution was analyzed; PTV coverage was required to be at least V{sub 95%} >98%. In addition, the change in PTV size and the changes in V{sub 10Gy}, V{sub 20Gy}, V{sub 30Gy}, V{sub 40Gy}, D{sub mean} and D{sub 2cc} for the stomach and for the duodenum were analyzed; differences were tested for significance using the Wilcoxon signed-rank test. Results: Using a midV approach resulted in sufficient target coverage. A highly significant PTV size reduction of 13.9% (P<.001) was observed. Also, all dose parameters for the stomach and duodenum, except the D{sub 2cc} of the duodenum, improved significantly (P≤.002). Conclusions: By using the midV approach to account for respiratory-induced tumor motion, a significant PTV reduction and significant dose reductions to the stomach and to the duodenum can be achieved when irradiating pancreatic tumors.

  17. Calculation of Lung Cancer Volume of Target Based on Thorax Computed Tomography Images using Active Contour Segmentation Method for Treatment Planning System

    NASA Astrophysics Data System (ADS)

    Patra Yosandha, Fiet; Adi, Kusworo; Edi Widodo, Catur

    2017-06-01

    In this research, calculation process of the lung cancer volume of target based on computed tomography (CT) thorax images was done. Volume of the target calculation was done in purpose to treatment planning system in radiotherapy. The calculation of the target volume consists of gross tumor volume (GTV), clinical target volume (CTV), planning target volume (PTV) and organs at risk (OAR). The calculation of the target volume was done by adding the target area on each slices and then multiply the result with the slice thickness. Calculations of area using of digital image processing techniques with active contour segmentation method. This segmentation for contouring to obtain the target volume. The calculation of volume produced on each of the targets is 577.2 cm3 for GTV, 769.9 cm3 for CTV, 877.8 cm3 for PTV, 618.7 cm3 for OAR 1, 1,162 cm3 for OAR 2 right, and 1,597 cm3 for OAR 2 left. These values indicate that the image processing techniques developed can be implemented to calculate the lung cancer target volume based on CT thorax images. This research expected to help doctors and medical physicists in determining and contouring the target volume quickly and precisely.

  18. Evaluation of potential internal target volume of liver tumors using cine-MRI.

    PubMed

    Akino, Yuichi; Oh, Ryoong-Jin; Masai, Norihisa; Shiomi, Hiroya; Inoue, Toshihiko

    2014-11-01

    Four-dimensional computed tomography (4DCT) is widely used for evaluating moving tumors, including lung and liver cancers. For patients with unstable respiration, however, the 4DCT may not visualize tumor motion properly. High-speed magnetic resonance imaging (MRI) sequences (cine-MRI) permit direct visualization of respiratory motion of liver tumors without considering radiation dose exposure to patients. Here, the authors demonstrated a technique for evaluating internal target volume (ITV) with consideration of respiratory variation using cine-MRI. The authors retrospectively evaluated six patients who received stereotactic body radiotherapy (SBRT) to hepatocellular carcinoma. Before acquiring planning CT, sagittal and coronal cine-MRI images were acquired for 30 s with a frame rate of 2 frames/s. The patient immobilization was conducted under the same condition as SBRT. Planning CT images were then acquired within 15 min from cine-MRI image acquisitions, followed by a 4DCT scan. To calculate tumor motion, the motion vectors between two continuous frames of cine-MRI images were calculated for each frame using the pyramidal Lucas-Kanade method. The target contour was delineated on one frame, and each vertex of the contour was shifted and copied onto the following frame using neighboring motion vectors. 3D trajectory data were generated with the centroid of the contours on sagittal and coronal images. To evaluate the accuracy of the tracking method, the motion of clearly visible blood vessel was analyzed with the motion tracking and manual detection techniques. The target volume delineated on the 50% (end-exhale) phase of 4DCT was translated with the trajectory data, and the distribution of the occupancy probability of target volume was calculated as potential ITV (ITV Potential). The concordance between ITV Potential and ITV estimated with 4DCT (ITV 4DCT) was evaluated using the Dice's similarity coefficient (DSC). The distance between blood vessel positions

  19. Evaluation of potential internal target volume of liver tumors using cine-MRI

    SciTech Connect

    Akino, Yuichi; Oh, Ryoong-Jin; Masai, Norihisa; Shiomi, Hiroya; Inoue, Toshihiko

    2014-11-01

    Purpose: Four-dimensional computed tomography (4DCT) is widely used for evaluating moving tumors, including lung and liver cancers. For patients with unstable respiration, however, the 4DCT may not visualize tumor motion properly. High-speed magnetic resonance imaging (MRI) sequences (cine-MRI) permit direct visualization of respiratory motion of liver tumors without considering radiation dose exposure to patients. Here, the authors demonstrated a technique for evaluating internal target volume (ITV) with consideration of respiratory variation using cine-MRI. Methods: The authors retrospectively evaluated six patients who received stereotactic body radiotherapy (SBRT) to hepatocellular carcinoma. Before acquiring planning CT, sagittal and coronal cine-MRI images were acquired for 30 s with a frame rate of 2 frames/s. The patient immobilization was conducted under the same condition as SBRT. Planning CT images were then acquired within 15 min from cine-MRI image acquisitions, followed by a 4DCT scan. To calculate tumor motion, the motion vectors between two continuous frames of cine-MRI images were calculated for each frame using the pyramidal Lucas–Kanade method. The target contour was delineated on one frame, and each vertex of the contour was shifted and copied onto the following frame using neighboring motion vectors. 3D trajectory data were generated with the centroid of the contours on sagittal and coronal images. To evaluate the accuracy of the tracking method, the motion of clearly visible blood vessel was analyzed with the motion tracking and manual detection techniques. The target volume delineated on the 50% (end-exhale) phase of 4DCT was translated with the trajectory data, and the distribution of the occupancy probability of target volume was calculated as potential ITV (ITV {sub Potential}). The concordance between ITV {sub Potential} and ITV estimated with 4DCT (ITV {sub 4DCT}) was evaluated using the Dice’s similarity coefficient (DSC). Results

  20. Modalities of Mechanical Ventilation: Volume-Targeted Versus Pressure-Limited.

    PubMed

    Lozano, Shanny M; Newnam, Katherine M

    2016-04-01

    Respiratory distress syndrome remains the most common admission diagnosis in the neonatal intensive care unit. Healthcare providers have a clear appreciation for the potential harm to pulmonary structures that have been associated with mechanical ventilation (MV) in the preterm infant. Although life sustaining, the goal is to optimally ventilate while limiting trauma to the neonatal lung in order to preserve long-term cardiopulmonary and neurodevelopmental outcomes. To describe, compare, and contrast 2 primary methods of neonatal MV, pressure-limited ventilation (PLV) and volume-targeted ventilation (VTV), highlighting key considerations during therapy. A comprehensive search of the literature was completed using the following databases: CINAHL, Cochrane, Google Scholar, and PubMed. Research articles that were published in English over the last 10 years were reviewed for key information to describe and support the topic. Expert content review was conducted prior to publication by respiratory care providers, neonatal nurse practitioners, staff nurses, and neonatologist. Technology is rapidly evolving, with the newest mechanical ventilators providing the clinician with real-time data not previously available. Advanced microprocessors and feedback mechanisms can better support various ventilatory strategies including PLV and VTV. Renewed interest in volume ventilation has led many clinicians to ask about current evidence to support ventilatory modalities with regard to timing, settings, and short- and long-term effects. The clinician understands that neonatal pulmonary status is frequently changing based on gestational age, current age, and physiologic influences. Evidence supporting recommendations for the described MV modalities of PLV and VTV is provided for both preterm and term neonates. Comparison between MV strategies, specifically PLV and VTV, including short- and long-term neurodevelopmental outcomes, is needed. Recommendations regarding physiologic tidal

  1. Localization Accuracy of the Clinical Target Volume During Image-Guided Radiotherapy of Lung Cancer

    SciTech Connect

    Hugo, Geoffrey D.; Weiss, Elisabeth; Badawi, Ahmed; Orton, Matthew

    2011-10-01

    Purpose: To evaluate the position and shape of the originally defined clinical target volume (CTV) over the treatment course, and to assess the impact of gross tumor volume (GTV)-based online computed tomography (CT) guidance on CTV localization accuracy. Methods and Materials: Weekly breath-hold CT scans were acquired in 17 patients undergoing radiotherapy. Deformable registration was used to propagate the GTV and CTV from the first weekly CT image to all other weekly CT images. The on-treatment CT scans were registered rigidly to the planning CT scan based on the GTV location to simulate online guidance, and residual error in the CTV centroids and borders was calculated. Results: The mean GTV after 5 weeks relative to volume at the beginning of treatment was 77% {+-} 20%, whereas for the prescribed CTV, it was 92% {+-} 10%. The mean absolute residual error magnitude in the CTV centroid position after a GTV-based localization was 2.9 {+-} 3.0 mm, and it varied from 0.3 to 20.0 mm over all patients. Residual error of the CTV centroid was associated with GTV regression and anisotropy of regression during treatment (p = 0.02 and p = 0.03, respectively; Spearman rank correlation). A residual error in CTV border position greater than 2 mm was present in 77% of patients and 50% of fractions. Among these fractions, residual error of the CTV borders was 3.5 {+-} 1.6 mm (left-right), 3.1 {+-} 0.9 mm (anterior-posterior), and 6.4 {+-} 7.5 mm (superior-inferior). Conclusions: Online guidance based on the visible GTV produces substantial error in CTV localization, particularly for highly regressing tumors. The results of this study will be useful in designing margins for CTV localization or for developing new online CTV localization strategies.

  2. Accuracy estimation for projection-to-volume targeting during rotational therapy: A feasibility study.

    PubMed

    Long, Yong; Fessler, Jeffrey A; Balter, James M

    2010-06-01

    Estimating motion and deformation parameters from a series of projection radiographs acquired during arc therapy using a reference CT volume has become a promising technique for targeting treatment. The purpose of this work is to investigate the influence of rotational arc length on maximum achievable accuracy of motion estimation. The projection-to-volume alignment procedure used a nonrigid model to describe motion in thorax area, a cost function consisting of a least-squared error metric and a simple regularizer that encourages local invertibility, and a four-level multiresolution scheme with a conjugate gradient method to optimize the cost function. The authors tested both small and large scale deformations typically found in the thorax of a radiotherapy patient at different breathing states and limited-angle scans of six angular widths (12°, 18°, 24°, 36°, 60°, and 90°) centered at three angles (0°, 45°, and 90°). The experiments illustrate the potential accuracy of limited-angle projection-to-volume alignment. Registration accuracy can be sensitive to angular center, tends to be lower along direction of the projection set, and tends to decrease away from the rotation center. The studies of small as well as large but realistically scaled deformations show similar dependencies. These trends appear to have fairly low sensitivity to quantum noise effects. There is potentially sufficient information present in a small spread of projections to monitor the configuration of reasonably high contrast tumors without implanted markers. © 2010 American Association of Physicists in Medicine.

  3. Determination of planning target volume for whole stomach irradiation using daily megavoltage computed tomographic images.

    PubMed

    Johnson, Matthew E; Pereira, Gisele C; El Naqa, Issam M; Goddu, S Murty; Al-Lozi, Rawan; Apte, Aditya; Mansur, David B

    2012-01-01

    Whole stomach radiation therapy is often used in the management of gastric lymphoma. However, very limited data exist with regard to planning target volume requirements for the whole stomach. This study retrospectively analyzed daily megavoltage computed tomographic (CT) scans of gastric lymphoma patients in order to help determine the interfraction variation of the stomach position. Forty-one daily megavoltage CT images from 3 gastric lymphoma patients were used for stomach contouring. Each patient's megavoltage CT images were rigidly registered to their CT simulation data sets, and the margin in each direction that covered at least 95% of the daily stomach volumes was computed using a simple grid search. Patient setup variation was also calculated from the daily patient shifts. The organ motion margin was then added to the setup margin to render the total margin. A uniform margin of 2.2 cm is required to cover 95% of the stomach over the treatment course. However, direction-specific margins were observed from 1.72, 1.88, 0.92, 2.23, 1.90, and 0.86 cm for the right, left, posterior, anterior, superior, and inferior directions, respectively. The results of this study provide helpful 3-dimensional volumetric information to the limited existing data on margin requirements for whole stomach radiation therapy. Copyright © 2012 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

  4. Postoperative Radiotherapy for Glioma: Improved Delineation of the Clinical Target Volume Using the Geodesic Distance Calculation

    PubMed Central

    Yan, DanFang; Yan, SenXiang; Lu, ZhongJie; Xie, Cong; Chen, Wei; Xu, Xing; Li, Xinke; Yu, Haogang; Zhu, Xinli; Zheng, LingYan

    2014-01-01

    Objects To introduce a new method for generating the clinical target volume (CTV) from gross tumor volume (GTV) using the geodesic distance calculation for glioma. Methods One glioblastoma patient was enrolled. The GTV and natural barriers were contoured on each slice of the computer tomography (CT) simulation images. Then, a graphic processing unit based on a parallel Euclidean distance transform was used to generate the CTV considering natural barriers. Three-dimensional (3D) visualization technique was applied to show the delineation results. Speed of operation and precision were compared between this new delineation method and the traditional method. Results In considering spatial barriers, the shortest distance from the point sheltered from these barriers equals the sum of the distance along the shortest path between the two points; this consists of several segments and evades the spatial barriers, rather than being the direct Euclidean distance between two points. The CTV was generated irregularly rather than as a spherical shape. The time required to generate the CTV was greatly reduced. Moreover, this new method improved inter- and intra-observer variability in defining the CTV. Conclusions Compared with the traditional CTV delineation, this new method using geodesic distance calculation not only greatly shortens the time to modify the CTV, but also has better reproducibility. PMID:24896082

  5. Clinicopathologic Analysis of Microscopic Extension in Lung Adenocarcinoma: Defining Clinical Target Volume for Radiotherapy

    SciTech Connect

    Grills, Inga S.; Fitch, Dwight L.; Goldstein, Neal S.; Yan Di; Chmielewski, Gary W.; Welsh, Robert J.; Kestin, Larry L.

    2007-10-01

    Purpose: To determine the gross tumor volume (GTV) to clinical target volume margin for non-small-cell lung cancer treatment planning. Methods: A total of 35 patients with Stage T1N0 adenocarcinoma underwent wedge resection plus immediate lobectomy. The gross tumor size and microscopic extension distance beyond the gross tumor were measured. The nuclear grade and percentage of bronchoalveolar features were analyzed for association with microscopic extension. The gross tumor dimensions were measured on a computed tomography (CT) scan (lung and mediastinal windows) and compared with the pathologic dimensions. The potential coverage of microscopic extension for two different lung stereotactic radiotherapy regimens was evaluated. Results: The mean microscopic extension distance beyond the gross tumor was 7.2 mm and varied according to grade (10.1, 7.0, and 3.5 mm for Grade 1 to 3, respectively, p < 0.01). The 90th percentile for microscopic extension was 12.0 mm (13.0, 9.7, and 4.4 mm for Grade 1 to 3, respectively). The CT lung windows correlated better with the pathologic size than did the mediastinal windows (gross pathologic size overestimated by a mean of 5.8 mm; composite size [gross plus microscopic extension] underestimated by a mean of 1.2 mm). For a GTV contoured on the CT lung windows, the margin required to cover microscopic extension for 90% of the cases would be 9 mm (9, 7, and 4 mm for Grade 1 to 3, respectively). The potential microscopic extension dosimetric coverage (55 Gy) varied substantially between the stereotactic radiotherapy schedules. Conclusion: For lung adenocarcinomas, the GTV should be contoured using CT lung windows. Although a GTV based on the CT lung windows would underestimate the gross tumor size plus microscopic extension by only 1.2 mm for the average case, the clinical target volume expansion required to cover the microscopic extension in 90% of cases could be as large as 9 mm, although considerably smaller for high-grade tumors

  6. Radiotherapy planning for glioblastoma based on a tumor growth model: improving target volume delineation

    NASA Astrophysics Data System (ADS)

    Unkelbach, Jan; Menze, Bjoern H.; Konukoglu, Ender; Dittmann, Florian; Le, Matthieu; Ayache, Nicholas; Shih, Helen A.

    2014-02-01

    Glioblastoma differ from many other tumors in the sense that they grow infiltratively into the brain tissue instead of forming a solid tumor mass with a defined boundary. Only the part of the tumor with high tumor cell density can be localized through imaging directly. In contrast, brain tissue infiltrated by tumor cells at low density appears normal on current imaging modalities. In current clinical practice, a uniform margin, typically two centimeters, is applied to account for microscopic spread of disease that is not directly assessable through imaging. The current treatment planning procedure can potentially be improved by accounting for the anisotropy of tumor growth, which arises from different factors: anatomical barriers such as the falx cerebri represent boundaries for migrating tumor cells. In addition, tumor cells primarily spread in white matter and infiltrate gray matter at lower rate. We investigate the use of a phenomenological tumor growth model for treatment planning. The model is based on the Fisher-Kolmogorov equation, which formalizes these growth characteristics and estimates the spatial distribution of tumor cells in normal appearing regions of the brain. The target volume for radiotherapy planning can be defined as an isoline of the simulated tumor cell density. This paper analyzes the model with respect to implications for target volume definition and identifies its most critical components. A retrospective study involving ten glioblastoma patients treated at our institution has been performed. To illustrate the main findings of the study, a detailed case study is presented for a glioblastoma located close to the falx. In this situation, the falx represents a boundary for migrating tumor cells, whereas the corpus callosum provides a route for the tumor to spread to the contralateral hemisphere. We further discuss the sensitivity of the model with respect to the input parameters. Correct segmentation of the brain appears to be the most

  7. [Margin determination from clinical to planning target volume for lung cancer treated with conformal or intensity-modulated irradiation].

    PubMed

    Berthelot, K; Thureau, S; Giraud, P

    2016-10-01

    Technological progress in radiotherapy enables more precision for treatment planning and delivery. The margin determination between the clinical target volume and the planning target volumes stem from the estimation of geometric uncertainties of the tumour localization into the radiation beam. The inner motion complexity of lung tumours has led to the use of 4D computed tomography and nurtures specific dosimetric concerns. Few strategies consisting in integrating tumour motion allow margin reduction regarding inner movements. The patient immobilization and onboard imagery improvement decrease the setup uncertainties. Each step between the initial planning imagery and treatment delivery has to be analysed as systematic or random errors to calculate the optimal planning margin.

  8. Differences in Effective Target Volume Between Various Techniques of Accelerated Partial Breast Irradiation

    SciTech Connect

    Shaitelman, Simona F.; Vicini, Frank A.; Grills, Inga S.; Martinez, Alvaro A.; Yan Di; Kim, Leonard H.

    2012-01-01

    Purpose: Different cavity expansions are used to define the clinical target volume (CTV) for accelerated partial breast irradiation (APBI) delivered via balloon brachytherapy (1 cm) vs. three-dimensional conformal radiotherapy (3D-CRT) (1.5 cm). Previous studies have argued that the CTVs generated by these different margins are effectively equivalent. In this study, we use deformable registration to assess the effective CTV treated by balloon brachytherapy on clinically representative 3D-CRT planning images. Methods and Materials: Ten patients previously treated with the MammoSite were studied. Each patient had two computed tomography (CT) scans, one acquired before and one after balloon implantation. In-house deformable registration software was used to deform the MammoSite CTV onto the balloonless CT set. The deformed CTV was validated using anatomical landmarks common to both CT scans. Results: The effective CTV treated by the MammoSite was on average 7% {+-} 10% larger and 38% {+-} 4% smaller than 3D-CRT CTVs created using uniform expansions of 1 and 1.5 cm, respectively. The average effective CTV margin was 1.0 cm, the same as the actual MammoSite CTV margin. However, the effective CTV margin was nonuniform and could range from 5 to 15 mm in any given direction. Effective margins <1 cm were attributable to poor cavity-balloon conformance. Balloon size relative to the cavity did not significantly correlate with the effective margin. Conclusion: In this study, the 1.0-cm MammoSite CTV margin treated an effective volume that was significantly smaller than the 3D-CRT CTV based on a 1.5-cm margin.

  9. Stereotactic radiosurgery (SRS) in high-grade glioma: judicious selection of small target volumes improves results.

    PubMed

    Bokstein, Felix; Blumenthal, Deborah T; Corn, Benjamin W; Gez, Eliahu; Matceyevsky, Diana; Shtraus, Natan; Ram, Zvi; Kanner, Andrew A

    2016-02-01

    We present a retrospective review of 55 Stereotactic Radiosurgery (SRS) procedures performed in 47 consecutive patients with high-grade glioma (HGG). Thirty-three (70.2%) patients were diagnosed with glioblastoma and 14 (29.8%) with grade III glioma. The indications for SRS were small (up to 30 mm in diameter) locally progressing lesions in 32/47 (68%) or new distant lesions in 15/47 (32%) patients. The median target volume was 2.2 cc (0.2-9.5 cc) and the median prescription dose was 18 Gy (14-24 Gy). Three patients (5.5% incidence in 55 treatments) developed radiation necrosis. In eight cases (17%) patients received a second salvage SRS treatment to nine new lesions detected during follow-up. In 22/55 SRS treatments (40.0%) patients received concurrent chemo- or biological therapy, including temozolamide (TMZ) (15 patients), bevacizumab (BVZ) (6 patients) and carboplatin in one patient. Median time to progression after SRS was 5.0 months (1.0-96.4). Median survival time after SRS was 15.9 months (2.3-109.3) overall median survival (since diagnosis) was 37.4 months (9.6-193.6 months). Long-lasting responses (>12 months) after SRS were observed in 25/46 (54.3%) patients. We compared a matched (histology, age, KPS) cohort of patients with recurrent HGG treated with BVZ alone with the current study group. Median survival was significantly longer for SRS treated patients compared to the BVZ only cohort (12.6 vs. 7.3 months, p = 0.0102). SRS may be considered an effective salvage procedure for selected patients with small volume, recurrent high-grade gliomas. Long-term radiological control was observed in more than 50% of the patients.

  10. Impact Factors for Microinvasion in Intrahepatic Cholangiocarcinoma: A Possible System for Defining Clinical Target Volume

    SciTech Connect

    Bi Aihong; Zeng Zhaochong; Ji Yuan; Zeng Haiying; Xu Chen; Tang Zhaoyou; Fan Jia; Zhou Jian; Zeng Mengsu; Tan Yunshan

    2010-12-01

    Purpose: To quantify microscopic invasion of intrahepatic cholangiocarcinoma (IHC) into nontumor tissue and define the gross tumor volume (GTV)-to-clinical target volume (CTV) expansion necessary for radiotherapy. Methods and Materials: One-hundred IHC patients undergoing radical resection from January 2004 to July 2008 were enrolled in this study. Pathologic and clinical data including maximum tumor diameter, tumor boundary type, TNM stage, histologic grade, tumor markers, and liver enzymes were reviewed. The distance of microinvasion from the tumor boundary was measured by microscopy. The contraction coefficient for tumor measurements in radiographs and slide-mounted tissue was calculated. SPSS15.0 was used for statistical analysis. Results: Sixty-five patients (65%) exhibited tumor microinvasions. Microinvasions ranged from 0.4-8 mm, with 96% of patients having a microinvasion distance {<=}6 mm measured on slide. The radiograph-to-slide contraction coefficient was 82.1%. The degree of microinvasion was correlated with tumor boundary type, TNM stage, histologic grade, and serum levels of carbohydrate antigen 19-9, alanine aminotransferase, aspartate aminotransferase, {gamma}-glutamyltransferase and alkaline phosphatase. To define CTV accurately, we devised a scoring system based on combination of these factors. According to this system, a score {<=}1.5 is associated with 96.1% sensitivity in detecting patients with a microextension {<=}4.9 mm in radiographs, whereas a score {>=}2 has a 95.1% sensitivity in detecting microextension {<=}7.9 mm measured on radiograph. Conclusions: Patients with a score {<=}1.5 and {>=}2 require a radiographic GTV-to-CTV expansions of 4.9 and 7.9 mm, respectively, to encompass >95% of microinvasions.

  11. Anatomic Boundaries of the Clinical Target Volume (Prostate Bed) After Radical Prostatectomy

    SciTech Connect

    Wiltshire, Kirsty L.; Brock, Kristy K.; Haider, Masoom A.; Zwahlen, Daniel; Kong, Vickie; Chan, Elisa; Moseley, Joanne; Bayley, Andrew; Catton, Charles; Chung, Peter W.M.; Gospodarowicz, Mary; Milosevic, Michael; Kneebone, Andrew; Warde, Padraig; Menard, Cynthia

    2007-11-15

    Purpose: We sought to derive and validate an interdisciplinary consensus definition for the anatomic boundaries of the postoperative clinical target volume (CTV, prostate bed). Methods and Materials: Thirty one patients who had planned for radiotherapy after radical prostatectomy were enrolled and underwent computed tomography and magnetic resonance imaging (MRI) simulation prior to radiotherapy. Through an iterative process of consultation and discussion, an interdisciplinary consensus definition was derived based on a review of published data, patterns of local failure, surgical practice, and radiologic anatomy. In validation, we analyzed the distribution of surgical clips in reference to the consensus CTV and measured spatial uncertainties in delineating the CTV and vesicourethral anastomosis. Clinical radiotherapy plans were retrospectively evaluated against the consensus CTV (prostate bed). Results: Anatomic boundaries of the consensus CTV (prostate bed) are described. Surgical clips (n = 339) were well distributed throughout the CTV. The vesicourethral anastomosis was accurately localized using central sagittal computed tomography reconstruction, with a mean {+-} standard deviation uncertainty of 1.8 {+-} 2.5 mm. Delineation uncertainties were small for both MRI and computed tomography (mean reproducibility, 0-3.8 mm; standard deviation, 1.0-2.3); they were most pronounced in the anteroposterior and superoinferior dimensions and at the superior/posterior-most aspect of the CTV. Retrospectively, the mean {+-} standard deviation CTV (prostate bed) percentage of volume receiving 100% of prescribed dose was only 77% {+-} 26%. Conclusions: We propose anatomic boundaries for the CTV (prostate bed) and present evidence supporting its validity. In the absence of gross recurrence, the role of MRI in delineating the CTV remains to be confirmed. The CTV is larger than historically practiced at our institution and should be encompassed by a microscopic tumoricidal dose.

  12. Uncertainties in target volume delineation in radiotherapy – are they relevant and what can we do about them?

    PubMed Central

    Segedin, Barbara

    2016-01-01

    Abstract Background Modern radiotherapy techniques enable delivery of high doses to the target volume without escalating dose to organs at risk, offering the possibility of better local control while preserving good quality of life. Uncertainties in target volume delineation have been demonstrated for most tumour sites, and various studies indicate that inconsistencies in target volume delineation may be larger than errors in all other steps of the treatment planning and delivery process. The aim of this paper is to summarize the degree of delineation uncertainties for different tumour sites reported in the literature and review the effect of strategies to minimize them. Conclusions Our review confirmed that interobserver variability in target volume contouring represents the largest uncertainty in the process for most tumour sites, potentially resulting in a systematic error in dose delivery, which could influence local control in individual patients. For most tumour sites the optimal combination of imaging modalities for target delineation still needs to be determined. Strict use of delineation guidelines and protocols is advisable both in every day clinical practice and in clinical studies to diminish interobserver variability. Continuing medical education of radiation oncologists cannot be overemphasized, intensive formal training on interpretation of sectional imaging should be included in the program for radiation oncology residents. PMID:27679540

  13. Generating lung tumor internal target volumes from 4D-PET maximum intensity projections

    PubMed Central

    Lamb, J. M.; Robinson, C.; Bradley, J.; Laforest, R.; Dehdashti, F.; White, B. M.; Wuenschel, S.; Low, D. A.

    2011-01-01

    Purpose: Positron emission tomography (PET) of lung tumors suffers from breathing-motion induced blurring. Respiratory-correlated PET ameliorates motion blurring and enables visualization of lung tumor functional uptake throughout the breathing cycle but has achieved limited clinical use in radiotherapy planning. In this work, the authors propose a process for generating a gated PET maximum intensity projection (MIP), a breathing-phase projection of the 4D image set comprising gated PET images, as a technique to quantitatively and efficiently incorporate respiratory-correlated PET information into radiotherapy treatment planning.Methods: 4D-CT and respiratory-gated PET using [18F]fluorodeoxyglucose (FDG) were acquired of three patients with a total of four small (4–18 cc), clearly defined lower-lobe lung tumors. Internal target volumes (ITVs) for the lung tumors were generated by threshold-based segmentation of PET-MIP images and ungated PET images (ITVPET-MIP and ITV3D-PET, respectively), and by manual contouring of CT-MIP and end-exhale and end-inhale phases of 4D-CT (ITVCT-MIP) by a radiation oncologist. Because of the sensitivity of tumor segmentation to threshold value, several different thresholds were tested for ITV generation, including 40%, 30%, and 20% of maximum standardized uptake value (SUVmax) for FDG as well as absolute SUV thresholds of 2.5 and 3.0. The normalized overlap and relative volumes of ITVPET-MIP and ITV3D-PET with respect to ITVCT-MIP were compared. The images were also visually compared. ITVCT-MIP was considered a gold standard for these tumors with CT-visible morphology.Results: The mean and standard deviation normalized overlap and relative volumes between ITVPET-MIP and ITVCT-MIP were 0.68 ± 0.07 and 1.07 ± 0.42, respectively, averaged over all four tumors and all five threshold values. The mean and standard deviation normalized overlap and relative volumes of ITV3D-PET and ITVCT-MIP were 0.47 ± 0.12 and 0.69 ± 0

  14. Early changes of volume and spatial location in target and normal tissues caused by IMRT for cervical cancer.

    PubMed

    Chen, Jianwu; Liu, Ping; Chen, Wenjuan; Bai, Penggang; Li, Jiangshan; Ni, Xiaolei; Chen, Kaiqiang; Li, Qixin

    2016-12-01

    To investigate the early changes of volume and spatial location in target and normal tissues caused by intensity-modulated radiotherapy (IMRT) for cervical cancer. Forty patients with cervical cancer were included in this study and treated by IMRT. Computed tomography (CT) was performed before radiotherapy and when the patient had received 27 Gy in 15 fractions. After image registration, the volume of interest (VOI) for the targets and organs at risk was delineated by clinicians on the CT images. Changes of volume, spatial location and Dice similarity were calculated for all VOIs. There were significant changes in gross tumor volume (GTV) in the primary tumor (GTV-T) with t = 8.304 (p<0.01) and visible pelvic lymph nodes (GTV-N) with t = 4.996 (p<0.01) caused by IMRT. The mean volume differences for GTV-T and GTV-N were 38.64% ± 19.50% (range 3.16%-86.49%) and 42.49% ± 25.68% (range 2.79%-87.42%), respectively. Among the organs at risk, the bladder had the greatest volume change with 55.13% ± 33.40% (range 3.25%-116.01%). The Dice similarity for GTV-T and GTV-N was 0.50 ± 0.18 (range 0.10-0.85) and 0.31 ± 0.20 (range 0.00-0.71), respectively. The rectum had the least Dice similarity among the normal tissues, with a mean value of 0.57 ± 0.14 (range 0.18-0.76). There were significant changes in volume and spatial location of the target and normal tissues after 27 Gy IMRT. In order to maintain the radiation dose to the targets and minimize the radiation to normal tissues, it is necessary to modify the radiotherapy planning.

  15. Dosimetric Comparison of Split Field and Fixed Jaw Techniques for Large IMRT Target Volumes in the Head and Neck

    SciTech Connect

    Srivastava, Shiv P.; Das, Indra J.; Kumar, Arvind; Johnstone, Peter A.S.

    2011-04-01

    Some treatment planning systems (TPSs), when used for large-field (>14 cm) intensity-modulated radiation therapy (IMRT), create split fields that produce excessive multiple-leaf collimator segments, match-line dose inhomogeneity, and higher treatment times than nonsplit fields. A new method using a fixed-jaw technique (FJT) forces the jaw to stay at a fixed position during optimization and is proposed to reduce problems associated with split fields. Dosimetric comparisons between split-field technique (SFT) and FJT used for IMRT treatment is presented. Five patients with head and neck malignancies and regional target volumes were studied and compared with both techniques. Treatment planning was performed on an Eclipse TPS using beam data generated for Varian 2100C linear accelerator. A standard beam arrangement consisting of nine coplanar fields, equally spaced, was used in both techniques. Institutional dose-volume constraints used in head and neck cancer were kept the same for both techniques. The dosimetric coverage for the target volumes between SFT and FJT for head and neck IMRT plan is identical within {+-}1% up to 90% dose. Similarly, the organs at risk (OARs) have dose-volume coverage nearly identical for all patients. When the total monitor unit (MU) and segments were analyzed, SFT produces statistically significant higher segments (17.3 {+-} 6.3%) and higher MU (13.7 {+-} 4.4%) than the FJT. There is no match line in FJT and hence dose uniformity in the target volume is superior to the SFT. Dosimetrically, SFT and FJT are similar for dose-volume coverage; however, the FJT method provides better logistics, lower MU, shorter treatment time, and better dose uniformity. The number of segments and MU also has been correlated with the whole body radiation dose with long-term complications. Thus, FJT should be the preferred option over SFT for large target volumes.

  16. Dosimetric comparison of split field and fixed jaw techniques for large IMRT target volumes in the head and neck.

    PubMed

    Srivastava, Shiv P; Das, Indra J; Kumar, Arvind; Johnstone, Peter A S

    2011-01-01

    Some treatment planning systems (TPSs), when used for large-field (>14 cm) intensity-modulated radiation therapy (IMRT), create split fields that produce excessive multiple-leaf collimator segments, match-line dose inhomogeneity, and higher treatment times than nonsplit fields. A new method using a fixed-jaw technique (FJT) forces the jaw to stay at a fixed position during optimization and is proposed to reduce problems associated with split fields. Dosimetric comparisons between split-field technique (SFT) and FJT used for IMRT treatment is presented. Five patients with head and neck malignancies and regional target volumes were studied and compared with both techniques. Treatment planning was performed on an Eclipse TPS using beam data generated for Varian 2100C linear accelerator. A standard beam arrangement consisting of nine coplanar fields, equally spaced, was used in both techniques. Institutional dose-volume constraints used in head and neck cancer were kept the same for both techniques. The dosimetric coverage for the target volumes between SFT and FJT for head and neck IMRT plan is identical within ± 1% up to 90% dose. Similarly, the organs at risk (OARs) have dose-volume coverage nearly identical for all patients. When the total monitor unit (MU) and segments were analyzed, SFT produces statistically significant higher segments (17.3 ± 6.3%) and higher MU (13.7 ± 4.4%) than the FJT. There is no match line in FJT and hence dose uniformity in the target volume is superior to the SFT. Dosimetrically, SFT and FJT are similar for dose-volume coverage; however, the FJT method provides better logistics, lower MU, shorter treatment time, and better dose uniformity. The number of segments and MU also has been correlated with the whole body radiation dose with long-term complications. Thus, FJT should be the preferred option over SFT for large target volumes. Copyright © 2011 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights

  17. Note: Development of a volume-limited dot target for a high brightness extreme ultraviolet microplasma source

    SciTech Connect

    Dinh, Thanh Hung Suzuki, Yuhei; Hara, Hiroyuki; Higashiguchi, Takeshi; Hirose, Ryoichi; Ohashi, Hayato; Li, Bowen; Dunne, Padraig; O’Sullivan, Gerry; Sunahara, Atsushi

    2014-11-15

    We report on production of volume-limited dot targets based on electron beam lithographic and sputtering technologies for use in efficient high brightness extreme ultraviolet microplasma sources. We successfully produced cylindrical tin (Sn) targets with diameters of 10, 15, and 20 μm and a height of 150 nm. The calculated spectrum around 13.5 nm was in good agreement with that obtained experimentally.

  18. Sphaeropsidin A shows promising activity against drug-resistant cancer cells by targeting regulatory volume increase

    PubMed Central

    Mathieu, Véronique; Chantôme, Aurélie; Lefranc, Florence; Cimmino, Alessio; Miklos, Walter; Paulitschke, Verena; Mohr, Thomas; Maddau, Lucia; Kornienko, Alexander; Berger, Walter; Vandier, Christophe; Evidente, Antonio; Delpire, Eric; Kiss, Robert

    2016-01-01

    Despite the recent advances in the treatment of tumors with intrinsic chemotherapy resistance, such as melanoma and renal cancers, their prognosis remains poor and new chemical agents with promising activity against these cancers are urgently needed. Sphaeropsidin A, a fungal metabolite whose anticancer potential had previously received little attention, was isolated from Diplodia cupressi and found to display specific anticancer activity in vitro against melanoma and kidney cancer subpanels in the National Cancer Institute (NCI) 60-cell line screen. The NCI data revealed a mean LC50 of ca. 10 μM and a cellular sensitivity profile that did not match that of any other agent in the 765,000 compound database. Subsequent mechanistic studies in melanoma and other multidrug-resistant in vitro cancer models showed that sphaeropsidin A can overcome apoptosis as well as multidrug resistance by inducing a marked and rapid cellular shrinkage related to the loss of intracellular Cl− and the decreased HCO3− concentration in the culture supernatant. These changes in ion homeostasis and the absence of effects on the plasma membrane potential were attributed to the sphaeropsidin A-induced impairment of regulatory volume increase (RVI). Preliminary results also indicate that depending on the type of cancer, the sphaeropsidin A effects on RVI could be related to Na–K–2Cl electroneutral cotransporter or Cl−/HCO3− anion exchanger(s) targeting. This study underscores the modulation of ion-transporter activity as a promising therapeutic strategy to combat drug-resistant cancers and identifies the fungal metabolite, sphaeropsidin A, as a lead to develop anticancer agents targeting RVI in cancer cells. PMID:25868554

  19. WE-D-17A-04: Magnetically Focused Proton Irradiation of Small Volume Targets

    SciTech Connect

    McAuley, G; Slater, J; Wroe, A

    2014-06-15

    Purpose: To explore the advantages of magnetic focusing for small volume proton irradiations and the potential clinical benefits for radiosurgery targets. The primary goal is to create narrow elongated proton beams of elliptical cross section with superior dose delivery characteristics compared to current delivery modalities (eg, collimated beams). In addition, more general beam shapes are also under investigation. Methods: Two prototype magnets consisting of 24 segments of samarium-cobalt (Sm2Co17) permanent magnetic material adhered into hollow cylinders were manufactured for testing. A single focusing magnet was placed on a positioning track on our Gantry 1 treatment table and 15 mm diameter proton beams with energies and modulation relevant to clinical radiosurgery applications (127 to 186 MeV, and 0 to 30 mm modulation) were delivered to a terminal water tank. Beam dose distributions were measured using a PTW diode detector and Gafchromic EBT2 film. Longitudinal and transverse dose profiles were analyzed and compared to data from Monte Carlo simulations analogous to the experimental setup. Results: The narrow elongated focused beam spots showed high elliptical symmetry indicating high magnet quality. In addition, when compared to unfocused beams, peak-to-entrance depth dose ratios were 11 to 14% larger (depending on presence or extent of modulation), and minor axis penumbras were 11 to 20% smaller (again depending on modulation) for focused beams. These results suggest that the use of rare earth magnet assemblies is practical and could improve dose-sparing of normal tissue and organs at risk while delivering enhanced dose to small proton radiosurgery targets. Conclusion: Quadrapole rare earth magnetic assemblies are a promising and inexpensive method to counteract particle out scatter that tends to degrade the peak to entrance performance of small field proton beams. Knowledge gained from current experiments will inform the design of a prototype treatment

  20. Gross tumor volume and clinical target volume in prostate cancer: How do satellites relate to the index lesion.

    PubMed

    Hollmann, Birgit G; van Triest, Baukelien; Ghobadi, Ghazaleh; Groenendaal, Greetje; de Jong, Jeroen; van der Poel, Henk G; van der Heide, Uulke A

    2015-04-01

    There is an increasing interest for dose differentiation in prostate radiotherapy. The purpose of our study was to analyze the spatial distribution of tumor satellites inside the prostate. 61 prostatectomy specimens were stained with H&E. Tumor regions were delineated by the uro-pathologist. Volumes, distances and cell densities of all delineated tumor regions were measured and further analyzed. Multifocal disease was seen in 84% of the patients. The median number of tumor foci was 3. The median distance between the index lesion and the satellites was 1.0 cm, with a maximum of 4.4 cm. The index lesions accounted for 88% of the total tumor volume. The contribution of tumor foci<0.1 cm(3) to the total tumor volume was 2%. The median cell density of the index lesion and all satellites, regardless of size, were significantly higher than that of the prostate. Satellites do not appear in a limited margin around the index lesion (GTV). Consequently, a fixed CTV margin would not effectively cover all satellites. Thus if the aim is to treat all tumor foci, the entire prostate gland should be considered CTV. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  1. Clinical target volume delineation including elective nodal irradiation in preoperative and definitive radiotherapy of pancreatic cancer

    PubMed Central

    2012-01-01

    Background Radiotherapy (RT) is widely used in the treatment of pancreatic cancer. Currently, recommendation has been given for the delineation of the clinical target volume (CTV) in adjuvant RT. Based on recently reviewed pathologic data, the aim of this study is to propose criteria for the CTV definition and delineation including elective nodal irradiation (ENI) in the preoperative and definitive treatment of pancreatic cancer. Methods The anatomical structures of interest, as well as the abdominal vasculature were identified on intravenous contrast-enhanced CT scans of two different patients with pancreatic cancer of the head and the body. To delineate the lymph node area, a margin of 10 mm was added to the arteries. Results We proposed a set of guidelines for elective treatment of high-risk nodal areas and CTV delineation. Reference CT images were provided. Conclusions The proposed guidelines could be used for preoperative or definitive RT for carcinoma of the head and body of the pancreas. Further clinical investigations are needed to validate the defined CTVs. PMID:22691275

  2. Proposed definition of the vaginal cuff and paracolpium clinical target volume in postoperative uterine cervical cancer.

    PubMed

    Murakami, Naoya; Norihisa, Yoshiki; Isohashi, Fumiaki; Murofushi, Keiko; Ariga, Takuro; Kato, Tomoyasu; Inaba, Koji; Okamoto, Hiroyuki; Ito, Yoshinori; Toita, Takafumi; Itami, Jun

    2016-01-01

    The aim of this study was to develop an appropriate definition for vaginal cuff and paracolpium clinical target volume (CTV) for postoperative intensity modulated radiation therapy in patients with uterine cervical cancer. A working subgroup was organized within the Radiation Therapy Study Group of the Japan Clinical Oncology Group to develop a definition for the postoperative vaginal cuff and paracolpium CTV in December 2013. The group consisted of 5 radiation oncologists who specialized in gynecologic oncology and a gynecologic oncologist. A comprehensive literature review that included anatomy, surgery, and imaging fields was performed and was followed by multiple discreet face-to-face discussions and e-mail messages before a final consensus was reached. Definitions for the landmark structures in all directions that demarcate the vaginal cuff and paracolpium CTV were decided by consensus agreement of the working group. A table was created that showed boundary structures of the vaginal cuff and paracolpium CTV in each direction. A definition of the postoperative cervical cancer vaginal cuff and paracolpium CTV was developed. It is expected that this definition guideline will serve as a template for future radiation therapy clinical trial protocols, especially protocols involving intensity modulated radiation therapy. Copyright © 2016 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

  3. Intra and interfraction mediastinal nodal region motion: implications for internal target volume expansions.

    PubMed

    Thomas, Jonathan G; Kashani, Rojano; Balter, James M; Tatro, Daniel; Kong, Feng-Ming; Pan, Charlie C

    2009-01-01

    The purpose of this study was to determine the intra and interfraction motion of mediastinal lymph node regions. Ten patients with nonsmall-cell lung cancer underwent controlled inhale and exhale computed tomography (CT) scans during two sessions (40 total datasets) and mediastinal nodal stations 1-8 were outlined. Corresponding CT scans from different sessions were registered to remove setup error and, in this reference frame, the centroid of each nodal station was compared for right-left (RL), anterior-posterior (AP), and superior-inferior (SI) displacement. In addition, an anisotropic volume expansion encompassing the change of the nodal region margins in all directions was used. Intrafraction displacement was determined by comparing same session inhale-exhale scans. Interfraction reproducibility of nodal regions was determined by comparing the same respiratory phase scans between two sessions. Intrafraction displacement of centroid varied between nodal stations. All nodal regions moved posteriorly and superiorly with exhalation, and inferior nodal stations showed the most motion. Based on anisotropic expansion, nodal regions expanded mostly in the RL direction from inhale to exhale. The interpatient variations in intrafraction displacement were large compared with the displacements themselves. Moreover, there was substantial interfractional displacement ( approximately 5 mm). Mediastinal lymph node regions clearly move during breathing. In addition, deformation of nodal regions between inhale and exhale occurs. The degree of motion and deformation varies by station and by individual. This study indicates the potential advantage of characterizing individualized nodal region motion to safely maximize conformality of mediastinal nodal targets.

  4. The ADVANCE project: Formal evaluation of the targeted deployment. Volume 1

    SciTech Connect

    1997-01-01

    The Advanced Driver and Vehicle Advisory Navigation ConcEpt (ADVANCE) was an invehicle advanced traveler information system (ATIS) that operated in the northwest suburbs of Chicago, Illinois. It was designed to provide origin-destination shortest-time route guidance to a vehicle based on (a) an on-board static (fixed) data base of average network link travel times by time of day, combined as available and appropriate with (b) dynamic (real-time) information on traffic conditions provided by radio frequency (RF) communications to and from a traffic information center (TIC). Originally conceived in 1990 as a major project that would have installed 3,000 to 5,000 route guidance units in privately owned vehicles throughout the test area, ADVANCE was restructured in 1995 as a {open_quotes}targeted deployment,{close_quotes} in which approximately 80 vehicles were to be equipped with the guidance units - Mobile Navigation Assistants (MNAs) - to be in full communication with the TIC while driving the ADVANCE test area road system. Volume one consists of the evaluation managers overview report, and several appendices containing test results.

  5. Assessment of target volume doses in radiotherapy based on the standard and measured calibration curves.

    PubMed

    Mohammadi, Gholamreza Fallah; Alam, Nader Riyahi; Rezaeejam, Hamed; Pourfallah, Tayyeb Allahverdi; Zakariaee, Seyed Salman

    2015-01-01

    In radiation treatments, estimation of the dose distribution in the target volume is one of the main components of the treatment planning procedure. To estimate the dose distribution, the information of electron densities is necessary. The standard curves determined by computed tomography (CT) scanner that may be different from that of other oncology centers. In this study, the changes of dose calculation due to the different calibration curves (HU-ρel) were investigated. Dose values were calculated based on the standard calibration curve that was predefined for the treatment planning system (TPS). The calibration curve was also extracted from the CT images of the phantom, and dose values were calculated based on this curve. The percentage errors of the calculated values were determined. The statistical analyses of the mean differences were performed using the Wilcoxon rank-sum test for both of the calibration curves. The results show no significant difference for both of the measured and standard calibration curves (HU-ρel) in 6, 15, and 18 MeV energies. In Wilcoxon ranked sum nonparametric test for independent samples with P<0.05, the equality of monitor units for both of the curves to transfer 200 cGy doses to reference points was resulted. The percentage errors of the calculated values were lower than 2% and 1.5% in 6 and 15 MeV, respectively. From the results, it could be concluded that the standard calibration curve could be used in TPS dose calculation accurately.

  6. Impact of Node Negative Target Volume Delineation on Contralateral Parotid Gland Dose Sparing Using IMRT in Head and Neck Cancer.

    PubMed

    Magnuson, William J; Urban, Erich; Bayliss, R Adam; Harari, Paul M

    2015-06-01

    There is considerable practice variation in treatment of the node negative (N0) contralateral neck in patients with head and neck cancer. In this study, we examined the impact of N0 neck target delineation volume on radiation dose to the contralateral parotid gland. Following institutional review board approval, 12 patients with head and neck cancer were studied. All had indications for treatment of the N0 neck, such as midline base of tongue or soft palate extension or advanced ipsilateral nodal disease. The N0 neck volumes were created using the Radiation Therapy Oncology Group head and neck contouring atlas. The physician-drawn N0 neck clinical target volume (CTV) was expanded by 25% to 200% to generate volume variation, followed by a 3-mm planning target volume (PTV) expansion. Surrounding organs at risk were contoured and complete intensity-modulated radiation therapy plans were generated for each N0 volume expansion. The median N0 target volume drawn by the radiation oncologist measured 93 cm(3) (range 71-145). Volumetric expansion of the N0 CTV by 25% to 200% increased the resultant mean dose to the contralateral parotid gland by 1.4 to 8.5 Gray (Gy). For example, a 4.1-mm increase in the N0 neck CTV translated to a 2.0-Gy dose increase to the parotid, 7.4 mm to a 4.5 Gy dose increase, and 12.5 mm to an 8.5 Gy dose increase, respectively. The treatment volume designated for the N0 neck has profound impact on resultant dose to the contralateral parotid gland. Variations of up to 15 mm are routine across physicians in target contouring, reflecting individual preference and training expertise. Depending on the availability of immobilization and image guidance techniques, experts commonly recommend 3 to 10 mm margin expansions to generate the PTV. Careful attention to the original volume of the N0 neck CTV, as well as expansion margins, is important in achieving effective contralateral gland sparing to reduce the resultant xerostomia and dysguesia that may ensue

  7. The Coordination of Program Planning and Evaluation Systems for Occupational Education. Volume 2: A Targeting System for Occupational Education.

    ERIC Educational Resources Information Center

    Riverside Research Inst., New York, NY.

    The second volume of the final report deals with the targeting system--one of a hierarchy of systems required to support the effective delivery of superior occupational education. It determines that program objectives match student training in occupations, that the best choice of occupations in which to train students has been made, and that the…

  8. Use of volume-targeted non-invasive bilevel positive airway pressure ventilation in a patient with amyotrophic lateral sclerosis*,**

    PubMed Central

    Diaz-Abad, Montserrat; Brown, John Edward

    2014-01-01

    Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease in which most patients die of respiratory failure. Although volume-targeted non-invasive bilevel positive airway pressure (BPAP) ventilation has been studied in patients with chronic respiratory failure of various etiologies, its use in ALS has not been reported. We present the case of a 66-year-old woman with ALS and respiratory failure treated with volume-targeted BPAP ventilation for 15 weeks. Weekly data downloads showed that disease progression was associated with increased respiratory muscle weakness, decreased spontaneous breathing, and increased use of non-invasive positive pressure ventilation, whereas tidal volume and minute ventilation remained relatively constant. PMID:25210968

  9. FDG-PET/CT during concomitant chemo radiotherapy for esophageal cancer: Reducing target volumes to deliver higher radiotherapy doses.

    PubMed

    Nkhali, Lamyaa; Thureau, Sébastien; Edet-Sanson, Agathe; Doyeux, Kaya; Benyoucef, Ahmed; Gardin, Isabelle; Michel, Pierre; Vera, Pierre; Dubray, Bernard

    2015-06-01

    A planning study investigated whether reduced target volumes defined on FDG-PET/CT during radiotherapy allow total dose escalation without compromising normal tissue tolerance in patients with esophageal cancer. Ten patients with esophageal squamous cell carcinoma (SCC), candidate to curative-intent concomitant chemo-radiotherapy (CRT), had FDG-PET/CT performed in treatment position, before and during (Day 21) radiotherapy (RT). Four planning scenarios were investigated: 1) 50 Gy total dose with target volumes defined on pre-RT FDG-PET/CT; 2) 50 Gy with boost target volume defined on FDG-PET/CT during RT; 3) 66 Gy with target volumes from pre-RT FDG-PET/CT; and 4) 66 Gy with boost target volume from during-RT FDG-PET/CT. The median metabolic target volume decreased from 12.9 cm3 (minimum 3.7-maximum 44.8) to 5.0 cm3 (1.7-13.5) (p=0.01) between pre- and during-RCT FDG-PET/CT. The median PTV66 was smaller on during-RT than on baseline FDG-PET/CT [108 cm3 (62.5-194) vs. 156 cm3 (68.8-251), p=0.02]. When total dose was set to 50 Gy, planning on during-RT FDG-PET/CT was associated with a marginal reduction in normal tissues irradiation. When total dose was increased to 66 Gy, planning on during-RT PET yielded significantly lower doses to the spinal cord [Dmax=44.1Gy (40.8-44.9) vs. 44.7Gy (41.5-45.0), p=0.007] and reduced lung exposure [V20Gy=23.2% (17.3-27) vs. 26.8% (19.7-30.2), p=0.006]. This planning study suggests that adaptive RT based on target volume reduction assessed on FDG-PET/CT during treatment could facilitate dose escalation up to 66 Gy in patients with esophageal SCC.

  10. Analysis of FET-PET imaging for target volume definition in patients with gliomas treated with conformal radiotherapy.

    PubMed

    Rieken, Stefan; Habermehl, Daniel; Giesel, Frederik L; Hoffmann, Christoph; Burger, Ute; Rief, Harald; Welzel, Thomas; Haberkorn, Uwe; Debus, Jürgen; Combs, Stephanie E

    2013-12-01

    Modern radiotherapy (RT) techniques such as stereotactic RT, intensity-modulated RT, or particle irradiation allow local dose escalation with simultaneous sparing of critical organs. Several trials are currently investigating their benefit in glioma reirradiation and boost irradiation. Target volume definition is of critical importance especially when steep dose gradient techniques are employed. In this manuscript we investigate the impact of O-(2-(F-18)fluoroethyl)-l-tyrosine-positron emission tomography/computer tomography (FET-PET/CT) on target volume definition in low and high grade glioma patients undergoing either first or re-irradiation with particles. We investigated volumetric size and uniformity of magnetic resonance imaging (MRI)- vs. FET-PET/CT-derived gross tumor volumes (GTVs) and planning target volumes (PTVs) of 41 glioma patients. Clinical cases are presented to demonstrate potential benefits of integrating FET-PET/CT-planning into daily routine. Integrating FET-uptake into the delineation of GTVs yields larger volumes. Combined modality-derived PTVs are significantly enlarged in high grade glioma patients and in case of primary RT. The congruence of MRI and FET signals for the identification of glioma GTVs is poor with mean uniformity indices of 0.39. MRI-based PTVs miss 17% of FET-PET/CT-based GTVs. Non significant alterations were detected in low grade glioma patients and in those undergoing reirradiation. Target volume definition for malignant gliomas during initial RT may yield significantly differing results depending upon the imaging modality, which the contouring process is based upon. The integration of both MRI and FET-PET/CT may help to improve GTV coverage by avoiding larger incongruences between physical and biological imaging techniques. In low grade gliomas and in cases of reirradiation, more studies are needed in order to investigate a potential benefit of FET-PET/CT for planning of RT. Copyright © 2013 Elsevier Ireland Ltd. All

  11. Characteristics of Movement-Induced Dose Reduction in Target Volume: A Comparison Between Photon and Proton Beam Treatment

    SciTech Connect

    Yoon, Myonggeun; Shin, Dongho; Kwak, Jungwon; Park, Soah; Lim, Young Kyung; Kim, Dongwook; Park, Sung Yong Lee, Se Byeong; Shin, Kyung Hwan; Kim, Tae Hyun; Cho, Kwan Ho

    2009-10-01

    We compared the main characteristics of movement-induced dose reduction during photon and proton beam treatment, based on an analysis of dose-volume histograms. To simulate target movement, a target contour was delineated in a scanned phantom and displaced by 3 to 20 mm. Although the dose reductions to the target in the 2 treatment systems were similar for transverse (perpendicular to beam direction) target motion, they were completely different for longitudinal (parallel to beam direction) target motion. While both modalities showed a relationship between the degree of target shift and the reduction in dose coverage, dose reduction showed a strong directional dependence in proton beam treatment. Clinical simulation of target movement for a prostate cancer patient showed that, although coverage and conformity indices for a 6-mm lateral movement of the prostate were reduced by 9% and 16%, respectively, for proton beam treatment, they were reduced by only 1% and 7%, respectively, for photon treatment. This difference was greater for a 15-mm target movement in the lateral direction, which lowered the coverage and conformity indices by 34% and 54%, respectively, for proton beam treatment, but changed little during photon treatment. In addition, we found that the equivalent uniform dose (EUD) and homogeneity index show similar characteristics during target movement. These results suggest that movement-induced dose reduction differs significantly between photon and proton beam treatment. Attention should be paid to the target margin in proton beam treatment due to the distinct characteristics of heavy ion beams.

  12. Intra- and Inter-Fraction Mediastinal Nodal Region Motion: Implications for Internal Target Volume Expansions

    PubMed Central

    Thomas, Jonathan G.; Kashani, Rojano; Balter, James M.; Tatro, Daniel; Kong, Feng-Ming; Pan, Charlie C.

    2009-01-01

    Purpose/Objective The purpose of this study is to determine the intra- and inter-fraction motion of mediastinal lymph node regions. Materials/Methods Ten patients with non-small cell lung cancer underwent controlled inhale and exhale CT scans during two sessions (40 total data sets) and mediastinal nodal stations 1–8 [Chapet, et al, IJROBP 2005;63:170–8] were outlined. Corresponding CT scans from different sessions were registered to remove setup error and in this reference frame, the center-of-mass (COM) of each nodal station was compared for right-left (RL), anterior-posterior (AP), and superior-inferior (SI) displacement. In addition, an anisotropic volume expansion encompassing the change of the nodal region margins in all directions was used. Intra-fraction displacement was determined by comparing same session inhale-exhale scans. Inter-fraction reproducibility of nodal regions was determined by comparing the same respiratory phase scans between two sessions. Results Intra-fraction displacement of COM varied between nodal stations. All nodal regions moved posteriorly and superiorly with exhalation, and inferior nodal stations showed the most motion. Based on anisotropic expansion, nodal regions expanded mostly in the RL direction from inhale to exhale. The inter-patient variations in intra-fraction displacement were large compared to the displacements themselves. Moreover, there was substantial inter-fractional displacement (∼5 mm). Conclusions Mediastinal lymph node regions clearly move during breathing. Additionally, deformation of nodal regions between inhale and exhale occurs. The degree of motion and deformation varies by station and by individual. This study indicates the potential advantage of characterizing individualized nodal region motion to safely maximize conformality of mediastinal nodal targets. PMID:19410142

  13. Risks and benefits of reducing target volume margins in breast tangent radiotherapy.

    PubMed

    Basaula, Deepak; Quinn, Alexandra; Walker, Amy; Batumalai, Vikneswary; Kumar, Shivani; Delaney, Geoff P; Holloway, Lois

    2017-02-27

    This study investigates the potential benefits of planning target volume (PTV) margin reduction for whole breast radiotherapy in relation to dose received by organs at risk (OARs), as well as reductions in radiation-induced secondary cancer risk. Such benefits were compared to the increased radiation-induced secondary cancer risk attributed from increased ionizing radiation imaging doses. Ten retrospective patients' computed tomography datasets were considered. Three computerized treatment plans with varied PTV margins (0, 5 and 10 mm) were created for each patient complying with the Radiation Therapy Oncology Group (RTOG) 1005 protocol requirements. The BEIR VII lifetime attributable risk (LAR) model was used to estimate secondary cancer risk to OARs. The LAR was assessed for all treatment plans considering (a) doses from PTV margin variation and (b) doses from two (daily and weekly) kilovoltage cone beam computed tomography (kV CBCT) imaging protocols during the course of treatment. We found PTV margins from largest to smallest resulted in a mean OAR relative dose reduction of 31% (heart), 28% (lung) and 23% (contralateral breast) and the risk of radiation-induced secondary cancer by a relative 23% (contralateral breast) and 22% (contralateral lung). Daily image-guidance using kV CBCT increased the risk of radiation induced secondary cancer to the contralateral breast and contralateral lung by a relative 1.6-1.9% and 1.9-2.5% respectively. Despite the additional dose from kV CBCT for the two considered imaging protocols, smaller PTV margins would still result in an overall reduction in secondary cancer risk.

  14. Definition and delineation of the clinical target volume for rectal cancer

    SciTech Connect

    Roels, Sarah; Duthoy, Wim; Haustermans, Karin . E-mail: Karin.Haustermans@uzleuven.be; Penninckx, Freddy; Vandecaveye, Vincent; Boterberg, Tom; Neve, Wilfried de

    2006-07-15

    Purpose: Optimization of radiation techniques to maximize local tumor control and to minimize small bowel toxicity in locally advanced rectal cancer requires proper definition and delineation guidelines for the clinical target volume (CTV). The purpose of this investigation was to analyze reported data on the predominant locations and frequency of local recurrences and lymph node involvement in rectal cancer, to propose a definition of the CTV for rectal cancer and guidelines for its delineation. Methods and Materials: Seven reports were analyzed to assess the incidence and predominant location of local recurrences in rectal cancer. The distribution of lymphatic spread was analyzed in another 10 reports to record the relative frequency and location of metastatic lymph nodes in rectal cancer, according to the stage and level of the primary tumor. Results: The mesorectal, posterior, and inferior pelvic subsites are most at risk for local recurrences, whereas lymphatic tumor spread occurs mainly in three directions: upward into the inferior mesenteric nodes; lateral into the internal iliac lymph nodes; and, in a few cases, downward into the external iliac and inguinal lymph nodes. The risk for recurrence or lymph node involvement is related to the stage and the level of the primary lesion. Conclusion: Based on a review of articles reporting on the incidence and predominant location of local recurrences and the distribution of lymphatic spread in rectal cancer, we defined guidelines for CTV delineation including the pelvic subsites and lymph node groups at risk for microscopic involvement. We propose to include the primary tumor, the mesorectal subsite, and the posterior pelvic subsite in the CTV in all patients. Moreover, the lateral lymph nodes are at high risk for microscopic involvement and should also be added in the CTV.

  15. Defining the Clinical Target Volume for Bladder Cancer Radiotherapy Treatment Planning

    SciTech Connect

    Jenkins, Peter; Anjarwalla, Salim; Gilbert, Hugh; Kinder, Richard

    2009-12-01

    Purpose: There are currently no data for the expansion margin required to define the clinical target volume (CTV) around bladder tumors. This information is particularly relevant when perivesical soft tissue changes are seen on the planning scan. While this appearance may reflect extravesical extension (EVE), it may also be an artifact of previous transurethral resection (TUR). Methods and Materials: Eighty patients with muscle-invasive bladder cancer who had undergone radical cystectomy were studied. All patients underwent preoperative TUR and staging computed tomography (CT) scans. The presence and extent of tumor growth beyond the outer bladder wall was measured radiologically and histopathologically. Results: Forty one (51%) patients had histologically confirmed tumor extension into perivesical fat. The median and mean extensions beyond the outer bladder wall were 1.7 and 3.1 mm, respectively. Thirty five (44%) patients had EVE, as seen on CT scans. The sensitivity and specificity of CT scans for EVE were 56% and 79%, respectively. False-positive results were infrequent and not affected by either the timing or the amount of tissue resected at TUR. CT scans consistently tended to overestimate the extent of EVE. Tumor size and the presence of either lymphovascular invasion or squamoid differentiation predict a greater extent of EVE. Conclusions: In patients with radiological evidence of extravesical disease, the CTV should comprise the outer bladder wall plus a 10-mm margin. In patients with no evidence of extravesical disease on CT scans, the CTV should be restricted to the outer bladder wall plus a 6-mm margin. These recommendations would encompass microscopic disease extension in 90% of cases.

  16. Variation in the Definition of Clinical Target Volumes for Pelvic Nodal Conformal Radiation Therapy for Prostate Cancer

    SciTech Connect

    Lawton, Colleen A.F. Michalski, Jeff; El-Naqa, Issam; Kuban, Deborah; Lee, W. Robert; Rosenthal, Seth A.; Zietman, Anthony; Sandler, Howard; Shipley, William; Ritter, Mark; Valicenti, Richard; Catton, Charles; Roach, Mack; Pisansky, Thomas M.; Seider, Michael

    2009-06-01

    Purpose: We conducted a comparative study of clinical target volume (CTV) definition of pelvic lymph nodes by multiple genitourinary (GU) radiation oncologists looking at the levels of discrepancies amongst this group. Methods and Materials: Pelvic computed tomography (CT) scans from 2 men were distributed to 14 Radiation Therapy Oncology Group GU radiation oncologists with instructions to define CTVs for the iliac and presacral lymph nodes. The CT data with contours were then returned for analysis. In addition, a questionnaire was completed that described the physicians' method for target volume definition. Results: Significant variation in the definition of the iliac and presacral CTVs was seen among the physicians. The minimum, maximum, mean (SD) iliac volumes (mL) were 81.8, 876.6, 337.6 {+-} 203 for case 1 and 60.3, 627.7, 251.8 {+-} 159.3 for case 2. The volume of 100% agreement was 30.6 and 17.4 for case 1 and 2 and the volume of the union of all contours was 1,012.0 and 807.4 for case 1 and 2, respectively. The overall agreement was judged to be moderate in both cases (kappa = 0.53 (p < 0.0001) and kappa = 0.48 (p < 0.0001). There was no volume of 100% agreement for either of the two presacral volumes. These variations were confirmed in the responses to the associated questionnaire. Conclusions: Significant disagreement exists in the definition of the CTV for pelvic nodal radiation therapy among GU radiation oncology specialists. A consensus needs to be developed so as to accurately assess the merit and safety of such treatment.

  17. Human-computer interaction in radiotherapy target volume delineation: a prospective, multi-institutional comparison of user input devices.

    PubMed

    2011-10-01

    The purpose of this study was the prospective comparison of objective and subjective effects of target volume region of interest (ROI) delineation using mouse-keyboard and pen-tablet user input devices (UIDs). The study was designed as a prospective test/retest sequence, with Wilcoxon signed rank test for matched-pair comparison. Twenty-one physician-observers contoured target volume ROIs on four standardized cases (representative of brain, prostate, lung, and head and neck malignancies) twice: once using QWERTY keyboard/scroll-wheel mouse UID and once with pen-tablet UID (DTX2100, Wacom Technology Corporation, Vancouver, WA, USA). Active task time, ROI manipulation task data, and subjective survey data were collected. One hundred twenty-nine target volume ROI sets were collected, with 62 paired pen-tablet/mouse-keyboard sessions. Active contouring time was reduced using the pen-tablet UID, with mean ± SD active contouring time of 26 ± 23 min, compared with 32 ± 25 with the mouse (p ≤ 0.01). Subjective estimation of time spent was also reduced from 31 ± 26 with mouse to 27 ± 22 min with the pen (p = 0.02). Task analysis showed ROI correction task reduction (p = 0.045) and decreased panning and scrolling tasks (p < 0.01) with the pen-tablet; drawing, window/level changes, and zoom commands were unchanged (p = n.s.) Volumetric analysis demonstrated no detectable differences in ROI volume nor intra- or inter-observer volumetric coverage. Fifty-two of 62 (84%) users preferred the tablet for each contouring task; 5 of 62 (8%) denoted no preference, and 5 of 62 (8%) chose the mouse interface. The pen-tablet UID reduced active contouring time and reduced correction of ROIs, without substantially altering ROI volume/coverage.

  18. Brain tumor target volume determination for radiation therapy treatment planning through the use of automated MRI segmentation

    NASA Astrophysics Data System (ADS)

    Mazzara, Gloria Patrika

    Radiation therapy seeks to effectively irradiate the tumor cells while minimizing the dose to adjacent normal cells. Prior research found that the low success rates for treating brain tumors would be improved with higher radiation doses to the tumor area. This is feasible only if the target volume can be precisely identified. However, the definition of tumor volume is still based on time-intensive, highly subjective manual outlining by radiation oncologists. In this study the effectiveness of two automated Magnetic Resonance Imaging (MRI) segmentation methods, k-Nearest Neighbors (kNN) and Knowledge-Guided (KG), in determining the Gross Tumor Volume (GTV) of brain tumors for use in radiation therapy was assessed. Three criteria were applied: accuracy of the contours; quality of the resulting treatment plan in terms of dose to the tumor; and a novel treatment plan evaluation technique based on post-treatment images. The kNN method was able to segment all cases while the KG method was limited to enhancing tumors and gliomas with clear enhancing edges. Various software applications were developed to create a closed smooth contour that encompassed the tumor pixels from the segmentations and to integrate these results into the treatment planning software. A novel, probabilistic measurement of accuracy was introduced to compare the agreement of the segmentation methods with the weighted average physician volume. Both computer methods under-segment the tumor volume when compared with the physicians but performed within the variability of manual contouring (28% +/- 12% for inter-operator variability). Computer segmentations were modified vertically to compensate for their under-segmentation. When comparing radiation treatment plans designed from physician-defined tumor volumes with treatment plans developed from the modified segmentation results, the reference target volume was irradiated within the same level of conformity. Analysis of the plans based on post

  19. {sup 11}C-methionine PET improves the target volume delineation of meningiomas treated with stereotactic fractionated radiotherapy

    SciTech Connect

    Grosu, Anca-Ligia . E-mail: anca-ligia.grosu@lrz.tum.de; Weber, Wolfgang A.; Astner, Sabrina T.; Adam, Markus; Krause, Bernd J.; Schwaiger, Markus; Molls, Michael; Nieder, Carsten

    2006-10-01

    Purpose: To evaluate the role of {sup 11}C-methionine positron emission tomography (MET-PET) in target volume delineation for meningiomas and to determine the interobserver variability. Methods and Materials: Two independent observers performed treatment planning in 10 patients according to a prospective written protocol. In the first step, they used coregistered computed tomography (CT) and magnetic resonance imaging (MRI). In the second step, MET-PET was added to CT/MRI (image fusion based on mutual information). Results: The correlation between gross tumor volume (GTVs) delineated by the two observers based on CT/MRI was r = 0.855 (Spearman's correlation coefficient, p = 0.002) and r = 0.988 (p = 0.000) when MET-PET/CT/MRI were used. The number of patients with agreement in more then 80% of the outlined volume increased with the availability of MET-PET from 1 in 10 to 5 in 10. The median volume of intersection between the regions delineated by two observers increased significantly from 69% (from the composite volume) to 79%, by the addition of MET-PET (p = 0.005). The information of MET-PET was useful to delineate GTV in the area of cavernous sinus, orbit, and base of the skull. Conclusions: The hypothesis-generating findings of potential normal tissue sparing and reduced interobserver variability provide arguments for invasive studies of the correlation between MET-PET images and histologic tumor extension and for prospective trials of target volume delineation with CT/MRI/MET-PET image fusion.

  20. A New Suggestion for the Radiation Target Volume After a Subtotal Gastrectomy in Patients With Stomach Cancer

    SciTech Connect

    Nam, Heerim; Lim, Do Hoon Kim, Sung; Kang, Won Ki; Sohn, Tae Sung; Noh, Jae Hyung; Kim, Yong Il; Park, Chan Hyung; Park, Chul Keun; Ahn, Yong Chan; Huh, Seung Jae

    2008-06-01

    Purpose: To compare treatment results between the use of two different radiation fields including and excluding remnant stomach and suggest new target volumes excluding remnant stomach after subtotal gastrectomy (STG) in patients with stomach cancer. Methods and Materials: We retrospectively analyzed 291 patients treated with adjuvant chemoradiotherapy after STG and D2 dissection at the Samsung Medical Center, Seoul, South Korea. Eighty-three patients registered from 1995 to 1997 underwent irradiation according to the INT 0116 protocol that recommended the inclusion of remnant stomach within the target volume (Group A). After this period, we excluded remnant stomach from the target volume for 208 patients (Group B). Median follow-up was 67 months. Results: Treatment failure developed in 93 patients (32.0%). Local and regional recurrence rates for Group A vs. Group B were 10.8% vs. 5.3% (p = not significant) and 9.6% vs. 6.3% (p = not significant), and recurrence rates for remnant stomach were 7.2% vs. 1.4% (p = 0.018), respectively. Overall and disease-free survival rates were not different between the two groups. Grade 3 or 4 vomiting and diarrhea developed more frequently in Group A than Group B (4.8% vs. 1.4% and 6.0% vs. 1.9%, respectively; p = 0.012; p < 0.001). Conclusion: Exclusion of remnant stomach from the radiation field had no effect on failure rates or survival, and a low complication rate occurred in patients treated excluding remnant stomach. We suggest that remnant stomach be excluded from the radiation target volume for patients with stomach cancer who undergo STG and D2 dissection.

  1. Recurrence pattern of squamous cell carcinoma in the midthoracic esophagus: implications for the clinical target volume design of postoperative radiotherapy

    PubMed Central

    Wang, Xiaoli; Luo, Yijun; Li, Minghuan; Yan, Hongjiang; Sun, Mingping; Fan, Tingyong

    2016-01-01

    Background Postoperative radiotherapy has shown positive efficacy in lowering the recurrence rate and improving the survival rate for patients with esophageal squamous cell carcinoma (ESCC). However, controversies still exist about the postoperative prophylactic radiation target volume. This study was designed to analyze the patterns of recurrence and to provide a reference for determination of the postoperative radiotherapy target volume for patients with midthoracic ESCC. Patients and methods A total of 338 patients with recurrent or metastatic midthoracic ESCC after radical surgery were retrospectively examined. The patterns of recurrence including locoregional and distant metastasis were analyzed for these patients. Results The rates of lymph node (LN) metastasis were 28.4% supraclavicular, 77.2% upper mediastinal, 32.0% middle mediastinal, 50.0% lower mediastinal, and 19.5% abdominal LNs. In subgroup analyses, the rate of abdominal LN metastasis was significantly higher in patients with histological node-positive than that in patients with histological node-negative (P=0.033). Further analysis in patients with histological node-positive demonstrated that patients with three or more positive nodes are more prone to abdominal LN metastasis, compared with patients with one or two positive nodes (χ2=4.367, P=0.037). The length of tumor and histological differentiation were also the high-risk factors for abdominal LN metastasis. Conclusion For midthoracic ESCC with histological node-negative, or one or two positive nodes, the supraclavicular and stations 2, 4, 5, and 7 LNs should be delineated as clinical target volume of postoperative prophylactic irradiation, and upper abdominal LNs should be excluded. While for midthoracic ESCC with three or more positive nodes, upper abdominal LNs should also be included. The length of tumor and histological differentiation should be considered comprehensively to design the clinical target volume for radiotherapy. PMID

  2. Using injectable hydrogel markers to assess resimulation for boost target volume definition in a patient undergoing whole-breast radiotherapy

    SciTech Connect

    Patel, Henal; Goyal, Sharad; Kim, Leonard

    2015-01-01

    Several publications have recommended that patients undergoing whole-breast radiotherapy be resimulated for boost planning. The rationale for this is that the seroma may be smaller when compared with the initial simulation. However, the decision remains whether to use the earlier or later images to define an appropriate boost target volume. A patient undergoing whole-breast radiotherapy had new, injectable, temporary hydrogel fiducial markers placed 1 to 3 cm from the seroma at the time of initial simulation. The patient was resimulated 4.5 weeks later for conformal photon boost planning. Computed tomography (CT) scans acquired at the beginning and the end of whole-breast radiotherapy showed that shrinkage of the lumpectomy cavity was not matched by a corresponding reduction in the surrounding tissue volume, as demarcated by hydrogel markers. This observation called into question the usual interpretation of cavity shrinkage for boost target definition. For this patient, it was decided to define the boost target volume on the initial planning CT instead of the new CT.

  3. Comparison of Magnetic Resonance Imaging and Computed Tomography for Breast Target Volume Delineation in Prone and Supine Positions.

    PubMed

    Pogson, Elise M; Delaney, Geoff P; Ahern, Verity; Boxer, Miriam M; Chan, Christine; David, Steven; Dimigen, Marion; Harvey, Jennifer A; Koh, Eng-Siew; Lim, Karen; Papadatos, George; Yap, Mei Ling; Batumalai, Vikneswary; Lazarus, Elizabeth; Dundas, Kylie; Shafiq, Jesmin; Liney, Gary; Moran, Catherine; Metcalfe, Peter; Holloway, Lois

    2016-11-15

    To determine whether T2-weighted MRI improves seroma cavity (SC) and whole breast (WB) interobserver conformity for radiation therapy purposes, compared with the gold standard of CT, both in the prone and supine positions. Eleven observers (2 radiologists and 9 radiation oncologists) delineated SC and WB clinical target volumes (CTVs) on T2-weighted MRI and CT supine and prone scans (4 scans per patient) for 33 patient datasets. Individual observer's volumes were compared using the Dice similarity coefficient, volume overlap index, center of mass shift, and Hausdorff distances. An average cavity visualization score was also determined. Imaging modality did not affect interobserver variation for WB CTVs. Prone WB CTVs were larger in volume and more conformal than supine CTVs (on both MRI and CT). Seroma cavity volumes were larger on CT than on MRI. Seroma cavity volumes proved to be comparable in interobserver conformity in both modalities (volume overlap index of 0.57 (95% Confidence Interval (CI) 0.54-0.60) for CT supine and 0.52 (95% CI 0.48-0.56) for MRI supine, 0.56 (95% CI 0.53-0.59) for CT prone and 0.55 (95% CI 0.51-0.59) for MRI prone); however, after registering modalities together the intermodality variation (Dice similarity coefficient of 0.41 (95% CI 0.36-0.46) for supine and 0.38 (0.34-0.42) for prone) was larger than the interobserver variability for SC, despite the location typically remaining constant. Magnetic resonance imaging interobserver variation was comparable to CT for the WB CTV and SC delineation, in both prone and supine positions. Although the cavity visualization score and interobserver concordance was not significantly higher for MRI than for CT, the SCs were smaller on MRI, potentially owing to clearer SC definition, especially on T2-weighted MR images. Copyright © 2016. Published by Elsevier Inc.

  4. Validation of a 4D-PET Maximum Intensity Projection for Delineation of an Internal Target Volume

    SciTech Connect

    Callahan, Jason; Kron, Tomas; Schneider-Kolsky, Michal; Dunn, Leon; Thompson, Mick; Siva, Shankar; Aarons, Yolanda; Binns, David; Hicks, Rodney J.

    2013-07-15

    Purpose: The delineation of internal target volumes (ITVs) in radiation therapy of lung tumors is currently performed by use of either free-breathing (FB) {sup 18}F-fluorodeoxyglucose-positron emission tomography-computed tomography (FDG-PET/CT) or 4-dimensional (4D)-CT maximum intensity projection (MIP). In this report we validate the use of 4D-PET-MIP for the delineation of target volumes in both a phantom and in patients. Methods and Materials: A phantom with 3 hollow spheres was prepared surrounded by air then water. The spheres and water background were filled with a mixture of {sup 18}F and radiographic contrast medium. A 4D-PET/CT scan was performed of the phantom while moving in 4 different breathing patterns using a programmable motion device. Nine patients with an FDG-avid lung tumor who underwent FB and 4D-PET/CT and >5 mm of tumor motion were included for analysis. The 3 spheres and patient lesions were contoured by 2 contouring methods (40% of maximum and PET edge) on the FB-PET, FB-CT, 4D-PET, 4D-PET-MIP, and 4D-CT-MIP. The concordance between the different contoured volumes was calculated using a Dice coefficient (DC). The difference in lung tumor volumes between FB-PET and 4D-PET volumes was also measured. Results: The average DC in the phantom using 40% and PET edge, respectively, was lowest for FB-PET/CT (DCAir = 0.72/0.67, DCBackground 0.63/0.62) and highest for 4D-PET/CT-MIP (DCAir = 0.84/0.83, DCBackground = 0.78/0.73). The average DC in the 9 patients using 40% and PET edge, respectively, was also lowest for FB-PET/CT (DC = 0.45/0.44) and highest for 4D-PET/CT-MIP (DC = 0.72/0.73). In the 9 lesions, the target volumes of the FB-PET using 40% and PET edge, respectively, were on average 40% and 45% smaller than the 4D-PET-MIP. Conclusion: A 4D-PET-MIP produces volumes with the highest concordance with 4D-CT-MIP across multiple breathing patterns and lesion sizes in both a phantom and among patients. Freebreathing PET/CT consistently

  5. Sparing Healthy Tissue and Increasing Tumor Dose Using Bayesian Modeling of Geometric Uncertainties for Planning Target Volume Personalization

    SciTech Connect

    Herschtal, Alan; Te Marvelde, Luc; Mengersen, Kerrie; Foroudi, Farshad; Eade, Thomas; Pham, Daniel; Caine, Hannah; Kron, Tomas

    2015-06-01

    Objective: To develop a mathematical tool that can update a patient's planning target volume (PTV) partway through a course of radiation therapy to more precisely target the tumor for the remainder of treatment and reduce dose to surrounding healthy tissue. Methods and Materials: Daily on-board imaging was used to collect large datasets of displacements for patients undergoing external beam radiation therapy for solid tumors. Bayesian statistical modeling of these geometric uncertainties was used to optimally trade off between displacement data collected from previously treated patients and the progressively accumulating data from a patient currently partway through treatment, to optimally predict future displacements for that patient. These predictions were used to update the PTV position and margin width for the remainder of treatment, such that the clinical target volume (CTV) was more precisely targeted. Results: Software simulation of dose to CTV and normal tissue for 2 real prostate displacement datasets consisting of 146 and 290 patients treated with a minimum of 30 fractions each showed that re-evaluating the PTV position and margin width after 8 treatment fractions reduced healthy tissue dose by 19% and 17%, respectively, while maintaining CTV dose. Conclusion: Incorporating patient-specific displacement patterns from early in a course of treatment allows PTV adaptation for the remainder of treatment. This substantially reduces the dose to healthy tissues and thus can reduce radiation therapy–induced toxicities, improving patient outcomes.

  6. SU-E-J-78: Internal Target Volume Delineation for Lung Tumors in Patients Treated with Robotic Radiosurgery

    SciTech Connect

    Descovich, M; Pinnaduwage, D; Kirby, N; Gottschalk, A; Yom, S; Pouliot, J; Braunstein, S

    2014-06-01

    Purpose: To compare different approaches for Internal Target Volume (ITV) delineation for patients treated with fiducial-free robotic radiosurgery for primary and metastatic lung tumors. Methods: Ten patients undergoing Lung-Optimized Treatment (LOT) for robotic radiosurgery were imaged with inhale and exhale breath-hold CT scans and 8-phase 4DCT scan. We evaluated the differences in internal target volume (ITV) delineated using three approaches: 1) maximum intensity projection (MIP) images reconstructed from 4DCT scan (ITV-MIP); 2) linear interpolation of Gross Tumor Volumes (GTV) segmented on inhale and exhale breath-hold scans (ITV-BH); 3) linear interpolation of GTV segmented on inhale and exhale phases of 4DCT scan (ITV-2Phase). All contours were independently generated by the same radiation oncologist using lung window settings. Patients had ITV-MIP volumes ranging from 1.5 to 146.9 cc (mean 36.8 cc) located in various parts of the lung. Volume overlap and matching index (MI) were calculated and compared. The MI between two volumes was defined as the ratio of their intersection to their union. MI of 1 indicates the volumes are identical; MI of 0 indicates that there is no overlap. Results: The three approaches generated very different results. The average (SD) MI for ITV-MIP and ITV-BH was 0.52 (0.24); for ITV-MIP and ITV-2Phase it was 0.69 (0.13); and for ITV-BH and ITV-2Phase was 0.57 (0.21), (ANOVA, p=0.16). Relative to the ITV-MIP, the percentage of volume overlap was 72% (26%) and 90% (7%) for ITV-BH and ITV-2Phase, respectively (t-test, p=0.05). Conclusion: Differences between ITV-BH and ITV-MIP are due to inconsistent lung filling at breath-hold and nonlinear tumor motion. Therefore, methods to check breath-hold scanning against regular patient breathing patterns should be developed. Whenever possible, ITV-BH generated by the LOT workflow should be verified by 4DCT data.

  7. FDG-PET/CT Imaging for Staging and Target Volume Delineation in Preoperative Conformal Radiotherapy of Rectal Cancer

    SciTech Connect

    Bassi, Maria Chiara; Turri, Lucia; Sacchetti, Gianmauro; Loi, Gianfranco; Cannillo, Barbara; La Mattina, Pierdaniele; Brambilla, Marco; Inglese, Eugenio; Krengli, Marco

    2008-04-01

    Purpose: To investigate the potential impact of using {sup 18}F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) on staging and target volume delineation for patients affected by rectal cancer and candidates for preoperative conformal radiotherapy. Methods and Materials: Twenty-five patients diagnosed with rectal cancer T3-4 N0-1 M0-1 and candidates for preoperative radiotherapy underwent PET/CT simulation after injection of 5.18 MBq/kg of FDG. Clinical stage was reassessed on the basis of FDG-PET/CT findings. The gross tumor volume (GTV) and the clinical target volume (CTV) were delineated first on CT and then on PET/CT images. The PET/CT-GTV and PET/CT-CTV were analyzed and compared with CT-GTV and CT-CTV, respectively. Results: In 4 of 25 cases (24%), PET/CT affected tumor staging or the treatment purpose. In 3 of 25 cases (12%) staged N0 M0, PET/CT showed FDG uptake in regional lymph nodes and in a case also in the liver. In a patient with a single liver metastasis PET/CT detected multiple lesions, changing the treatment intent from curative to palliative. The PET/CT-GTV and PET/CT-CTV were significantly greater than the CT-GTV (p = 0.00013) and CT-CTV (p = 0.00002), respectively. The mean difference between PET/CT-GTV and CT-GTV was 25.4% and between PET/CT-CTV and CT-CTV was 4.1%. Conclusions: Imaging with PET/CT for preoperative radiotherapy of rectal cancer may lead to a change in staging and target volume delineation. Stage variation was observed in 12% of cases and a change of treatment intent in 4%. The GTV and CTV changed significantly, with a mean increase in size of 25% and 4%, respectively.

  8. Determination of Internal Target Volume From a Single Positron Emission Tomography/Computed Tomography Scan in Lung Cancer

    SciTech Connect

    Chang Guoping; Chang Tingting; Pan Tinsu; Clark, John W.; Mawlawi, Osama R.

    2012-05-01

    Purpose: The use of four-dimensional computed tomography (4D-CT) to determine the tumor internal target volume (ITV) is usually characterized by high patient radiation exposure. The objective of this study was to propose and evaluate an approach that relies on a single static positron emission tomography (PET)/CT scan to determine the ITV, thereby eliminating the need for 4D-CT and thus reduce patient radiation dose. Methods and Materials: The proposed approach is based on the concept that the observed PET image is the result of a joint convolution of an ideal PET image (free from motion and partial volume effect) with a motion-blurring kernel (MBK) and partial volume effect. In this regard, the MBK and tumor ITV are then estimated from the deconvolution of this joint model. To test this technique, phantom and patient studies were performed using different sphere/tumor sizes and motion trajectories. In all studies, a 4D-CT and a PET/CT image of the sphere/tumor were acquired. The ITV from the proposed technique was then compared to the maximum intensity projection (MIP) volume of the 4D-CT images. A Dice coefficient of the two volumes was calculated to represent the similarity between the two ITVs. Results: The average ITVs of the proposed technique were 97.2% {+-} 0.3% and 81.0% {+-} 16.7% similar to the MIP volume in the phantom and patient studies, respectively. The average dice coefficients were 0.87 {+-} 0.05 and 0.73 {+-} 0.16, respectively, for the two studies. Conclusion: Using the proposed approach, a single static PET/CT scan has the potential to replace a 4D-CT to determine the tumor ITV. This approach has the added advantage of reducing patient radiation exposure and determining the tumor MBK compared to 4D-CT/MIP-CT.

  9. SOLLIMS Sampler: Targeting Peace & Stability Operations Lessons & Best Practices. Volume 3, Issue 2

    DTIC Science & Technology

    2012-04-01

    influence in the politics of the province. In the southern portion of Ninewa, Sunni Arabs had endured four years of severe drought. Agricultural, mineral ...Valley: Sociocultural Impacts at the Local Level," by Jessica Lee and Maureen Farrell, Prism, Volume 2, Number 2, March 2011. Table of Contents

  10. Short Communication: Conformal Therapy for Peri-Ventricular Brain Tumors: Is Target Volume Deformation an Issue?

    SciTech Connect

    Bauman, Glenn Woodford, Curtis; Yartsev, Slav

    2008-04-01

    Physiologic variations in ventricular volumes could have important implications for treating patients with peri-ventricular brain tumors, yet no data exist in the literature addressing this issue. Daily megavoltage computed tomography (CT) scans in a patient with neurocytoma receiving fractionated radiation revealed minimal changes, suggesting that margins accounting for ventricular deformation are not necessary.

  11. Target Volume Delineation in Dynamic Positron Emission Tomography Based on Time Activity Curve Differences

    NASA Astrophysics Data System (ADS)

    Teymurazyan, Artur

    Tumor volume delineation plays a critical role in radiation treatment planning and simulation, since inaccurately defined treatment volumes may lead to the overdosing of normal surrounding structures and potentially missing the cancerous tissue. However, the imaging modality almost exclusively used to determine tumor volumes, X-ray Computed Tomography (CT), does not readily exhibit a distinction between cancerous and normal tissue. It has been shown that CT data augmented with PET can improve radiation treatment plans by providing functional information not available otherwise. Presently, static PET scans account for the majority of procedures performed in clinical practice. In the radiation therapy (RT) setting, these scans are visually inspected by a radiation oncologist for the purpose of tumor volume delineation. This approach, however, often results in significant interobserver variability when comparing contours drawn by different experts on the same PET/CT data sets. For this reason, a search for more objective contouring approaches is underway. The major drawback of conventional tumor delineation in static PET images is the fact that two neighboring voxels of the same intensity can exhibit markedly different overall dynamics. Therefore, equal intensity voxels in a static analysis of a PET image may be falsely classified as belonging to the same tissue. Dynamic PET allows the evaluation of image data in the temporal domain, which often describes specific biochemical properties of the imaged tissues. Analysis of dynamic PET data can be used to improve classification of the imaged volume into cancerous and normal tissue. In this thesis we present a novel tumor volume delineation approach (Single Seed Region Growing algorithm in 4D (dynamic) PET or SSRG/4D-PET) in dynamic PET based on TAC (Time Activity Curve) differences. A partially-supervised approach is pursued in order to allow an expert reader to utilize the information available from other imaging

  12. Stereotactic ultrasound for target volume definition in a patient with prostate cancer and bilateral total hip replacement.

    PubMed

    Boda-Heggemann, Judit; Haneder, Stefan; Ehmann, Michael; Sihono, Dwi Seno Kuncoro; Wertz, Hansjörg; Mai, Sabine; Kegel, Stefan; Heitmann, Sigrun; von Swietochowski, Sandra; Lohr, Frank; Wenz, Frederik

    2015-01-01

    Target-volume definition for prostate cancer in patients with bilateral metal total hip replacements (THRs) is a challenge because of metal artifacts in the planning computed tomography (CT) scans. Magnetic resonance imaging (MRI) can be used for matching and prostate delineation; however, at a spatial and temporal distance from the planning CT, identical rectal and vesical filling is difficult to achieve. In addition, MRI may also be impaired by metal artifacts, even resulting in spatial image distortion. Here, we present a method to define prostate target volumes based on ultrasound images acquired during CT simulation and online-matched to the CT data set directly at the planning CT. A 78-year-old patient with cT2cNxM0 prostate cancer with bilateral metal THRs was referred to external beam radiation therapy. T2-weighted MRI was performed on the day of the planning CT with preparation according to a protocol for reproducible bladder and rectal filling. The planning CT was obtained with the immediate acquisition of a 3-dimensional ultrasound data set with a dedicated stereotactic ultrasound system for online intermodality image matching referenced to the isocenter by ceiling-mounted infrared cameras. MRI (offline) and ultrasound images (online) were thus both matched to the CT images for planning. Daily image guided radiation therapy (IGRT) was performed with transabdominal ultrasound and compared with cone beam CT. Because of variations in bladder and rectal filling and metal-induced image distortion in MRI, soft-tissue-based matching of the MRI to CT was not sufficient for unequivocal prostate target definition. Ultrasound-based images could be matched, and prostate, seminal vesicles, and target volumes were reliably defined. Daily IGRT could be successfully completed with transabdominal ultrasound with good accordance between cone beam CT and ultrasound. For prostate cancer patients with bilateral THRs causing artifacts in planning CTs, ultrasound referenced to

  13. Threshold segmentation for PET target volume delineation in radiation treatment planning: the role of target-to-background ratio and target size.

    PubMed

    Brambilla, M; Matheoud, R; Secco, C; Loi, G; Krengli, M; Inglese, E

    2008-04-01

    A multivariable approach was adopted to study the dependence of the percentage threshold [TH(%)] used to define the boundaries of 18F-FDG positive tissue on emission scan duration (ESD) and activity at the start of acquisition (Aacq) for different target sizes and target-to-background (T/B) ratios. An anthropomorphic model, at least for counting rate characteristics, was used to study this dependence in conditions resembling the ones that can be encountered in the clinical studies. An annular ring of water bags of 3 cm thickness was fitted over an International Electro-technical Commission (IEC) phantom in order to obtain counting rates similar to those found in average patients. The scatter fraction of the modified IEC phantom was similar to the mean scatter fraction measured on patients, with a similar scanner. A supplemental set of microhollow spheres was positioned inside the phantom. The NEMA NU 2-2001 scatter phantom was positioned at the end of the IEC phantom to approximate the clinical situation of having activity that extends beyond the scanner field of view. The phantoms were filled with a solution of water and 18F (12 kBq/mL) and the spheres with various T/B ratios of 22.5, 10.3, and 3.6. Sequential imaging was performed to acquire PET images with varying background activity concentrations of about 12, 9, 6.4, 5.3, and 3.1 kBq/mL. The ESD was set to 60, 120, 180, and 240 s/bed. Data were fitted using two distinct multiple linear regression models for sphere ID < or = 10 mm and sphere ID > 10 mm. The fittings of both models were good with an R2 of 0.86 in both cases. Neither ESD nor Aacq resulted as significant predictors of the TH(%). For sphere ID < or =10 mm the target size was the most significant predictor of the TH(%), followed by the T/B ratio, while for sphere ID > 10 mm the explanatory power of the target size and T/B ratio were reversed, the T/B ratio being now the most important predictor of the TH(%). Both the target size and T/B ratio play a

  14. A Beam-Specific Planning Target Volume (PTV) Design for Proton Therapy to Account for Setup and Range Uncertainties

    SciTech Connect

    Park, Peter C.; Zhu, X. Ronald; Lee, Andrew K.; Sahoo, Narayan; Melancon, Adam D.; Zhang Lifei; Dong Lei

    2012-02-01

    Purpose: To report a method for explicitly designing a planning target volume (PTV) for treatment planning and evaluation in heterogeneous media for passively scattered proton therapy and scanning beam proton therapy using single-field optimization (SFO). Methods and Materials: A beam-specific PTV (bsPTV) for proton beams was derived by ray-tracing and shifting ray lines to account for tissue misalignment in the presence of setup error or organ motion. Range uncertainties resulting from inaccuracies in computed tomography-based range estimation were calculated for proximal and distal surfaces of the target in the beam direction. The bsPTV was then constructed based on local heterogeneity. The bsPTV thus can be used directly as a planning target as if it were in photon therapy. To test the robustness of the bsPTV, we generated a single-field proton plan in a virtual phantom. Intentional setup and range errors were introduced. Dose coverage to the clinical target volume (CTV) under various simulation conditions was compared between plans designed based on the bsPTV and a conventional PTV. Results: The simulated treatment using the bsPTV design performed significantly better than the plan using the conventional PTV in maintaining dose coverage to the CTV. With conventional PTV plans, the minimum coverage to the CTV dropped from 99% to 67% in the presence of setup error, internal motion, and range uncertainty. However, plans using the bsPTV showed minimal drop of target coverage from 99% to 94%. Conclusions: The conventional geometry-based PTV concept used in photon therapy does not work well for proton therapy. We investigated and validated a beam-specific PTV method for designing and evaluating proton plans.

  15. A clip-based protocol for breast boost radiotherapy provides clear target visualisation and demonstrates significant volume reduction over time

    SciTech Connect

    Lewis, Lorraine; Cox, Jennifer; Morgia, Marita; Atyeo, John; Lamoury, Gillian

    2015-09-15

    The clinical target volume (CTV) for early stage breast cancer is difficult to clearly identify on planning computed tomography (CT) scans. Surgical clips inserted around the tumour bed should help to identify the CTV, particularly if the seroma has been reabsorbed, and enable tracking of CTV changes over time. A surgical clip-based CTV delineation protocol was introduced. CTV visibility and its post-operative shrinkage pattern were assessed. The subjects were 27 early stage breast cancer patients receiving post-operative radiotherapy alone and 15 receiving post-operative chemotherapy followed by radiotherapy. The radiotherapy alone (RT/alone) group received a CT scan at median 25 days post-operatively (CT1rt) and another at 40 Gy, median 68 days (CT2rt). The chemotherapy/RT group (chemo/RT) received a CT scan at median 18 days post-operatively (CT1ch), a planning CT scan at median 126 days (CT2ch), and another at 40 Gy (CT3ch). There was no significant difference (P = 0.08) between the initial mean CTV for each cohort. The RT/alone cohort showed significant CTV volume reduction of 38.4% (P = 0.01) at 40 Gy. The Chemo/RT cohort had significantly reduced volumes between CT1ch: median 54 cm{sup 3} (4–118) and CT2ch: median 16 cm{sup 3}, (2–99), (P = 0.01), but no significant volume reduction thereafter. Surgical clips enable localisation of the post-surgical seroma for radiotherapy targeting. Most seroma shrinkage occurs early, enabling CT treatment planning to take place at 7 weeks, which is within the 9 weeks recommended to limit disease recurrence.

  16. Interobserver variability of clinical target volume delineation in supra-diaphragmatic Hodgkin's disease: a multi-institutional experience.

    PubMed

    Genovesi, Domenico; Cèfaro, Giampiero Ausili; Vinciguerra, Annamaria; Augurio, Antonietta; Di Tommaso, Monica; Marchese, Rita; Ricardi, Umberto; Filippi, Andrea Riccardo; Girinsky, Theodore; Di Biagio, Katiuscia; Belfiglio, Maurizio; Barbieri, Enza; Valentini, Vincenzo

    2011-06-01

    To determine interobserver variability in clinical target volume (CTV) of supra-diaphragmatic Hodgkin's lymphoma. At the 2008 AIRO (Italian Society of Radiation Oncology) Meeting, the Radiation Oncology Department of Chieti proposed a multi-institutional contouring dummy-run of two cases of early stage supra-diaphragmatic Hodgkin's lymphoma after chemotherapy. Clinical history, diagnostics, and planning CT imaging were available on Chieti's radiotherapy website (www.radioterapia.unich.it). Participating centers were requested to delineate the CTV and submit it to the coordinating center. To quantify interobserver variability of CTV delineations, the total volume, craniocaudal, laterolateral, and anteroposterior diameters were calculated. A total of 18 institutions for case A and 15 institutions for case B submitted the targets. Case A presented significant variability in total volume (range: 74.1-1,157.1 cc), craniocaudal (range: 6.5-22.5 cm; median: 16.25 cm), anteroposterior (range: 5.04-14.82 cm; median: 10.28 cm), and laterolateral diameters (range: 8.23-22.88 cm; median: 15.5 cm). Mean CTV was 464.8 cc (standard deviation: 280.5 cc). Case B presented significant variability in total volume (range: 341.8-1,662 cc), cranio-caudal (range: 8.0-28.5 cm; median: 23 cm), anteroposterior (range: 7.9-1.8 cm; median: 11.1 cm), and laterolateral diameters (range: 12.9-24.0 cm; median: 18.8 cm). Mean CTV was 926.0 cc (standard deviation: 445.7 cc). This significant variability confirms the need to apply specific guidelines to improve contouring uniformity in Hodgkin's lymphoma.

  17. Validation of a reaction volume reduction protocol for analysis of Y chromosome haplotypes targeting DNA databases.

    PubMed

    Souza, C A; Oliveira, T C; Crovella, S; Santos, S M; Rabêlo, K C N; Soriano, E P; Carvalho, M V D; Junior, A F Caldas; Porto, G G; Campello, R I C; Antunes, A A; Queiroz, R A; Souza, S M

    2017-04-28

    The use of Y chromosome haplotypes, important for the detection of sexual crimes in forensics, has gained prominence with the use of databases that incorporate these genetic profiles in their system. Here, we optimized and validated an amplification protocol for Y chromosome profile retrieval in reference samples using lesser materials than those in commercial kits. FTA(®) cards (Flinders Technology Associates) were used to support the oral cells of male individuals, which were amplified directly using the SwabSolution reagent (Promega). First, we optimized and validated the process to define the volume and cycling conditions. Three reference samples and nineteen 1.2 mm-diameter perforated discs were used per sample. Amplification of one or two discs (samples) with the PowerPlex(®) Y23 kit (Promega) was performed using 25, 26, and 27 thermal cycles. Twenty percent, 32%, and 100% reagent volumes, one disc, and 26 cycles were used for the control per sample. Thereafter, all samples (N = 270) were amplified using 27 cycles, one disc, and 32% reagents (optimized conditions). Data was analyzed using a study of equilibrium values between fluorophore colors. In the samples analyzed with 20% volume, an imbalance was observed in peak heights, both inside and in-between each dye. In samples amplified with 32% reagents, the values obtained for the intra-color and inter-color standard balance calculations for verification of the quality of the analyzed peaks were similar to those of samples amplified with 100% of the recommended volume. The quality of the profiles obtained with 32% reagents was suitable for insertion into databases.

  18. Quantification and Minimization of Uncertainties of Internal Target Volume for Stereotactic Body Radiation Therapy of Lung Cancer

    SciTech Connect

    Ge Hong; Cai Jing; Kelsey, Chris R.; Yin Fangfang

    2013-02-01

    Purpose: To quantify uncertainties in delineating an internal target volume (ITV) and to understand how these uncertainties may be individually minimized for stereotactic body radiation therapy (SBRT) of early stage non-small cell lung cancer (NSCLC). Methods and Materials: Twenty patients with NSCLC who were undergoing SBRT were imaged with free-breathing 3-dimensional computed tomography (3DCT) and 10-phase 4-dimensional CT (4DCT) for delineating gross tumor volume (GTV){sub 3D} and ITV{sub 10Phase} (ITV3). The maximum intensity projection (MIP) CT was also calculated from 10-phase 4DCT for contouring ITV{sub MIP} (ITV1). Then, ITV{sub COMB} (ITV2), ITV{sub 10Phase+GTV3D} (ITV4), and ITV{sub 10Phase+ITVCOMB} (ITV5) were generated by combining ITV{sub MIP} and GTV{sub 3D}, ITV{sub 10phase} and GTV{sub 3D}, and ITV{sub 10phase} and ITV{sub COMB}, respectively. All 6 volumes (GTV{sub 3D} and ITV1 to ITV5) were delineated in the same lung window by the same radiation oncologist. The percentage of volume difference (PVD) between any 2 different volumes was determined and was correlated to effective tumor diameter (ETD), tumor motion ranges, R{sub 3D}, and the amplitude variability of the recorded breathing signal (v) to assess their volume variations. Results: The mean (range) tumor motion (R{sub SI}, R{sub AP}, R{sub ML}, and R{sub 3D}) and breathing variability (v) were 7.6 mm (2-18 mm), 4.0 mm (2-8 mm), 3.3 mm (0-7.5 mm), 9.9 mm (4.1-18.7 mm), and 0.17 (0.07-0.37), respectively. The trend of volume variation was GTV{sub 3D} volumes were 11.1 {+-} 9.3 cc, 13.2 {+-} 10.5 cc, 14.9 {+-} 11.0 cc, 14.7 {+-} 11.4 cc, 15.9 {+-} 11.7 cc, and 16.4 {+-} 11.8 cc, respectively. All comparisons between the target volumes showed statistical significance (P{<=}.001), except for ITV2 and ITV3 (P=.594). The PVDs for all volume pairs correlated negatively with ETD (r{<=}-0.658, P{<=}.006) and positively with

  19. Hierarchical imaging: a new concept for targeted imaging of large volumes from cells to tissues.

    PubMed

    Wacker, Irene; Spomer, Waldemar; Hofmann, Andreas; Thaler, Marlene; Hillmer, Stefan; Gengenbach, Ulrich; Schröder, Rasmus R

    2016-12-12

    Imaging large volumes such as entire cells or small model organisms at nanoscale resolution seemed an unrealistic, rather tedious task so far. Now, technical advances have lead to several electron microscopy (EM) large volume imaging techniques. One is array tomography, where ribbons of ultrathin serial sections are deposited on solid substrates like silicon wafers or glass coverslips. To ensure reliable retrieval of multiple ribbons from the boat of a diamond knife we introduce a substrate holder with 7 axes of translation or rotation specifically designed for that purpose. With this device we are able to deposit hundreds of sections in an ordered way in an area of 22 × 22 mm, the size of a coverslip. Imaging such arrays in a standard wide field fluorescence microscope produces reconstructions with 200 nm lateral resolution and 100 nm (the section thickness) resolution in z. By hierarchical imaging cascades in the scanning electron microscope (SEM), using a new software platform, we can address volumes from single cells to complete organs. In our first example, a cell population isolated from zebrafish spleen, we characterize different cell types according to their organelle inventory by segmenting 3D reconstructions of complete cells imaged with nanoscale resolution. In addition, by screening large numbers of cells at decreased resolution we can define the percentage at which different cell types are present in our preparation. With the second example, the root tip of cress, we illustrate how combining information from intermediate resolution data with high resolution data from selected regions of interest can drastically reduce the amount of data that has to be recorded. By imaging only the interesting parts of a sample considerably less data need to be stored, handled and eventually analysed. Our custom-designed substrate holder allows reproducible generation of section libraries, which can then be imaged in a hierarchical way. We demonstrate, that EM

  20. Determination of Internal Target Volume for Radiation Treatment Planning of Esophageal Cancer by Using 4-Dimensional Computed Tomography (4DCT)

    SciTech Connect

    Chen, Xiaojian; Lu, Haijun; Tai, An; Johnstone, Candice; Gore, Elizabeth; Li, X. Allen

    2014-09-01

    Purpose: To determine an efficient strategy for the generation of the internal target volume (ITV) for radiation treatment planning for esophageal cancer using 4-dimensional computed tomography (4DCT). Methods and Materials: 4DCT sets acquired for 20 patients with esophageal carcinoma were analyzed. Each of the 4DCT sets was binned into 10 respiratory phases. For each patient, the gross tumor volume (GTV) was delineated on the 4DCT set at each phase. Various strategies to derive ITV were explored, including the volume from the maximum intensity projection (MIP; ITV{sub M}IP), unions of the GTVs from selected multiple phases ITV2 (0% and 50% phases), ITV3 (ITV2 plus 80%), and ITV4 (ITV3 plus 60%), as well as the volumes expanded from ITV2 and ITV3 with a uniform margin. These ITVs were compared to ITV10 (the union of the GTVs for all 10 phases) and the differences were measured with the overlap ratio (OR) and relative volume ratio (RVR) relative to ITV10 (ITVx/ITV10). Results: For all patients studied, the average GTV from a single phase was 84.9% of ITV10. The average ORs were 91.2%, 91.3%, 94.5%, and 96.4% for ITV{sub M}IP, ITV2, ITV3, and ITV4, respectively. Low ORs were associated with irregular breathing patterns. ITV3s plus 1 mm uniform margins (ITV3+1) led to an average OR of 98.1% and an average RVR of 106.4%. Conclusions: The ITV generated directly from MIP underestimates the range of the respiration motion for esophageal cancer. The ITV generated from 3 phases (ITV3) may be used for regular breathers, whereas the ITV generated from 4 phases (ITV4) or ITV3 plus a 1-mm uniform margin may be applied for irregular breathers.

  1. Evaluation of atlas based auto-segmentation for head and neck target volume delineation in adaptive/replan IMRT

    NASA Astrophysics Data System (ADS)

    Speight, R.; Karakaya, E.; Prestwich, R.; Sen, M.; Lindsay, R.; Harding, R.; Sykes, J.

    2014-03-01

    IMRT for head and neck patients requires clinicians to delineate clinical target volumes (CTV) on a planning-CT (>2hrs/patient). When patients require a replan-CT, CTVs must be re-delineated. This work assesses the performance of atlas-based autosegmentation (ABAS), which uses deformable image registration between planning and replan-CTs to auto-segment CTVs on the replan-CT, based on the planning contours. Fifteen patients with planning-CT and replan-CTs were selected. One clinician delineated CTVs on the planning-CTs and up to three clinicians delineated CTVs on the replan-CTs. Replan-CT volumes were auto-segmented using ABAS using the manual CTVs from the planning-CT as an atlas. ABAS CTVs were edited manually to make them clinically acceptable. Clinicians were timed to estimate savings using ABAS. CTVs were compared using dice similarity coefficient (DSC) and mean distance to agreement (MDA). Mean inter-observer variability (DSC>0.79 and MDA<2.1mm) was found to be greater than intra-observer variability (DSC>0.91 and MDA<1.5mm). Comparing ABAS to manual CTVs gave DSC=0.86 and MDA=2.07mm. Once edited, ABAS volumes agreed more closely with the manual CTVs (DSC=0.87 and MDA=1.87mm). The mean clinician time required to produce CTVs reduced from 169min to 57min when using ABAS. ABAS segments volumes with accuracy close to inter-observer variability however the volumes require some editing before clinical use. Using ABAS reduces contouring time by a factor of three.

  2. Evaluation of interfractional variation of the centroid position and volume of internal target volume during stereotactic body radiotherapy of lung cancer using cone-beam computed tomography.

    PubMed

    Sun, Yanan; Ge, Hong; Cheng, Siguo; Yang, Chengliang; Zhu, Qianqian; Li, Dingjie; Tian, Yuan

    2016-03-08

    The purpose of this study was to determine interfractional variation of the centroid position and volume of internal target volume (ITV) during stereotactic body radiation therapy (SBRT) of lung cancer. From January 2014 to August 2014, a total of 32 patients with 37 primary or metastatic lung tumors were enrolled in our study. All patients received SBRT treatment in 4-5 fractions to a median dose of 48 Gy. Both 3D CT and 4D CT scans were used for radiotherapy treatment planning. 3D CBCT was acquired prior to treatment delivery to verify patient positioning. A total of 163 3D CBCT images were available for evaluation. 3D CBCT scans acquired for verification were registered with simulation CT scans. The ITVs were contoured on all verification 3D CBCT scans and compared to the initial gross target volume (GTV) or ITV in treatment planning system. GTV was based on 3D CT while ITV was based on both 3D CT and 4D CT. To assess the interfractional variation of ITV centroid position, we used vertebrae body adja-cent to the tumor as reference point when performing the registration procedure. To eliminate the effect of time on tumor volume between simulation CT scan and the first fraction, the interfractional variation of ITV was evaluated from the first fraction to the last fraction. The overall 3D vector shift was 4.4 ± 2.5 mm (range: 0.4-13.8 mm). The interfractional variation of ITV centroid position in superior-inferior, anterior-posterior, and left-right directions were -0.7 ± 2.7 mm, -1.4 ± 3.4 mm, and -0.5 ± 2.2 mm, respectively. No significant difference was observed between three directions (p = 0.147). Large interfractional variations (≥ 5 mm) were observed in 12 fractions (9.3%) in superior-inferior direction, 24 fractions (18.6%) in anterior-posterior direction, and 5 fractions (3.9%) in left-right direction. No time trend of tumor volume change measured in 3D CBCT was detected during four fractions (p = 0.074). A significant (p = 0.010) time trend was

  3. Microspheres targeted with a mesothelin antibody and loaded with doxorubicin reduce tumor volume of human mesotheliomas in xenografts

    PubMed Central

    2013-01-01

    Background Malignant mesotheliomas (MMs) are chemoresistant tumors related to exposure to asbestos fibers. The long latency period of MM (30-40 yrs) and heterogeneity of tumor presentation make MM difficult to diagnose and treat at early stages. Currently approved second-line treatments following surgical resection of MMs include a combination of cisplatin or carboplatin (delivered systemically) and pemetrexed, a folate inhibitor, with or without subsequent radiation. The systemic toxicities of these treatments emphasize the need for more effective, localized treatment regimens. Methods Acid-prepared mesoporous silica (APMS) microparticles were loaded with doxorubicin (DOX) and modified externally with a mesothelin (MB) specific antibody before repeated intraperitoneal (IP) injections into a mouse xenograft model of human peritoneal MM. The health/weight of mice, tumor volume/weight, tumor necrosis and cell proliferation were evaluated in tumor-bearing mice receiving saline, DOX high (0.2 mg/kg), DOX low (0.05 mg/kg), APMS-MB, or APMS-MB-DOX (0.05 mg/kg) in saline. Results Targeted therapy (APMS-MB-DOX at 0.05 mg/kg) was more effective than DOX low (0.05 mg/kg) and less toxic than treatment with DOX high (0.2 mg/kg). It also resulted in the reduction of tumor volume without loss of animal health and weight, and significantly decreased tumor cell proliferation. High pressure liquid chromatography (HPLC) of tumor tissue confirmed that APMS-MB-DOX particles delivered DOX to target tissue. Conclusions Data suggest that targeted therapy results in greater chemotherapeutic efficacy with fewer adverse side effects than administration of DOX alone. Targeted microparticles are an attractive option for localized drug delivery. PMID:24024776

  4. Development of whole-building energy design targets for commercial buildings: Phase 1, Planning: Volume 2, Technical report

    SciTech Connect

    Crawley, D.B.; Briggs, R.S.; Jones, J.W.; Seaton, W.W.; Kaufman, J.E.; Deringer, J.J.; Kennett, E.W.

    1987-08-01

    This is the second volume of the Phase 1 report and discusses the 10 tasks performed in Phase 1. The objective of this research is to develop a methodology for setting energy design targets to provide voluntary guidelines for the buildings industry. The whole-building energy targets project is being conducted at the Pacific Northwest Laboratory (PNL) for the US Department of Energy (DOE) to encourage the construction of energy-efficient buildings by informing designers and owners about cost-effective goals for energy use in new commercial buildings. The outcome of this research will be a flexible methodology for setting such targets. The tasks are listed and discussed in this report as follows: Task 1 - Develop Detailed Project Goals and Objectives; Task 2 - Establish Buildings-Industry Liaison; Task 3 - Develop Approaches to the Energy Targets Model, Building Operations, and Climate; Task 4 - Develop an Approach for Treating Economic Considerations; Task 5 - Develop an Approach for Treating Energy Sources; Task 6 - Collect Energy-Use Data; Task 7 - Survey Energy Expert Opinion; Task 8 - Evaluation Procedure Specification and Integration; Task 9 - Phase 1 Report Development; and Task 10 - Phase 1 Review Planning.

  5. Physics of laser fusion. Volume II. Diagnostics of experiments on laser fusion targets at LLNL

    SciTech Connect

    Ahlstrom, H.G.

    1982-01-01

    These notes present the experimental basis and status for laser fusion as developed at LLNL. There are two other volumes in this series: Vol. I, by C.E. Max, presents the theoretical laser-plasma interaction physics; Vol. III, by J.F. Holzrichter et al., presents the theory and design of high-power pulsed lasers. A fourth volume will present the theoretical implosion physics. The notes consist of six sections. The first, an introductory section, provides some of the history of inertial fusion and a simple explanation of the concepts involved. The second section presents an extensive discussion of diagnostic instrumentation used in the LLNL Laser Fusion Program. The third section is a presentation of laser facilities and capabilities at LLNL. The purpose here is to define capability, not to derive how it was obtained. The fourth and fifth sections present the experimental data on laser-plasma interaction and implosion physics. The last chapter is a short projection of the future.

  6. [Metastatic characteristics of lymph node in supraclavicular zone and radiotherapy target volume for limited-stage small cell lung cancer].

    PubMed

    Feng, Zhen-xing; Zhao, Lu-jun; Guan, Yong; Sun, Yao; Ji, Kai; Wang, Ping

    2013-05-21

    To explore the reasonable radiotherapy range by analyzing the characteristics of supraclavicular lymph node metastasis in limited-stage small cell lung cancer (LS-SCLC). From January 2005 to December 2011, patients of LS-SCLC were reviewed. Supraclavicular zone was further divided into five subgroups including para-recurrent laryngeal nerve (region I and region II ), para-internal jugular vein (region III ), supraclavicular region (region IV), as well as the other regions except for the mentioned above (region V). The characteristics of the lymph nodes in each region were analyzed. The supraclavicular lymph node metastasis was found in 60 patients, with a positive rate of 34.5%. In multivariate Logistic regression analysis,intra-thoracic lymph node metastasis in the lymph node stations of level 2 and 3 were found to be the risk factors of supraclavicular lymph node metastasis (P = 0.006,P = 0.000). Our data suggests that the frequencies of metastasis in region I and III were much higher than those in the other areas.Among the sixty patients with supraclavicular lymph node metastasis, 95.0% were found at region I or III while the incidence of skip metastasis was only 5.0%. It is advisable to contain the bilateral supraclavicular nodes in patients with mediastinal lymph nodes metastasis to the level 2 or 3 for elective radiation target volume.The clinical target volume (CTV) exterior margin containing the outer margin of internal jugular vein may be suitable.

  7. The optimization of intensity modulated radiotherapy in cases where the planning target volume extends into the build-up region.

    PubMed

    Nguyen, T B; Hoole, A C F; Burnet, N G; Thomas, S J

    2009-04-21

    A common clinical problem in IMRT, especially when treating head and neck cases, is that the clinical target volume (CTV) stops short of the skin surface, whilst the margin for geometric uncertainties may take the planning target volume (PTV) to the skin surface or beyond. In these cases, optimization leads to over-dosing of the skin, unless the planner resorts to procedural tricks to avoid this, such as the use of pretend bolus or reduction of the PTV followed by adding 'flash' after optimization. This paper describes a method of avoiding the need for these tricks by using a multiple-isocentre CTV-based objective function. This enables plans to be produced that will give good coverage of the CTV for all the geometrical uncertainties that would have been covered by the PTV without causing the problem of over-dosing the skin. Eight isocentre shifts, equally distributed on the surface of a sphere with a radius equal to the CTV-PTV margin, are shown to be adequate for the optimization process. The resulting fluence maps are much simpler than those resulting from PTV optimization and will therefore be simpler to deliver. The method also permits better sparing of organs at risk such as the spinal cord.

  8. The optimization of intensity modulated radiotherapy in cases where the planning target volume extends into the build-up region

    NASA Astrophysics Data System (ADS)

    Nguyen, T. B.; Hoole, A. C. F.; Burnet, N. G.; Thomas, S. J.

    2009-04-01

    A common clinical problem in IMRT, especially when treating head and neck cases, is that the clinical target volume (CTV) stops short of the skin surface, whilst the margin for geometric uncertainties may take the planning target volume (PTV) to the skin surface or beyond. In these cases, optimization leads to over-dosing of the skin, unless the planner resorts to procedural tricks to avoid this, such as the use of pretend bolus or reduction of the PTV followed by adding 'flash' after optimization. This paper describes a method of avoiding the need for these tricks by using a multiple-isocentre CTV-based objective function. This enables plans to be produced that will give good coverage of the CTV for all the geometrical uncertainties that would have been covered by the PTV without causing the problem of over-dosing the skin. Eight isocentre shifts, equally distributed on the surface of a sphere with a radius equal to the CTV-PTV margin, are shown to be adequate for the optimization process. The resulting fluence maps are much simpler than those resulting from PTV optimization and will therefore be simpler to deliver. The method also permits better sparing of organs at risk such as the spinal cord.

  9. Elective Clinical Target Volumes for Conformal Therapy in Anorectal Cancer: A Radiation Therapy Oncology Group Consensus Panel Contouring Atlas

    SciTech Connect

    Myerson, Robert J. Garofalo, Michael C.; El Naqa, Issam; Abrams, Ross A.; Apte, Aditya; Bosch, Walter R.; Das, Prajnan; Gunderson, Leonard L.; Hong, Theodore S.; Kim, J.J. John; Willett, Christopher G.; Kachnic, Lisa A.

    2009-07-01

    Purpose: To develop a Radiation Therapy Oncology Group (RTOG) atlas of the elective clinical target volume (CTV) definitions to be used for planning pelvic intensity-modulated radiotherapy (IMRT) for anal and rectal cancers. Methods and Materials: The Gastrointestinal Committee of the RTOG established a task group (the nine physician co-authors) to develop this atlas. They responded to a questionnaire concerning three elective CTVs (CTVA: internal iliac, presacral, and perirectal nodal regions for both anal and rectal case planning; CTVB: external iliac nodal region for anal case planning and for selected rectal cases; CTVC: inguinal nodal region for anal case planning and for select rectal cases), and to outline these areas on individual computed tomographic images. The imaging files were shared via the Advanced Technology Consortium. A program developed by one of the co-authors (I.E.N.) used binomial maximum-likelihood estimates to generate a 95% group consensus contour. The computer-estimated consensus contours were then reviewed by the group and modified to provide a final contouring consensus atlas. Results: The panel achieved consensus CTV definitions to be used as guidelines for the adjuvant therapy of rectal cancer and definitive therapy for anal cancer. The most important difference from similar atlases for gynecologic or genitourinary cancer is mesorectal coverage. Detailed target volume contouring guidelines and images are discussed. Conclusion: This report serves as a template for the definition of the elective CTVs to be used in IMRT planning for anal and rectal cancers, as part of prospective RTOG trials.

  10. Histopathological correlation of (11)C-choline PET scans for target volume definition in radical prostate radiotherapy.

    PubMed

    Chang, Joe H; Joon, Daryl Lim; Lee, Sze Ting; Gong, Sylvia J; Scott, Andrew M; Davis, Ian D; Clouston, David; Bolton, Damien; Hamilton, Christopher S; Khoo, Vincent

    2011-05-01

    To evaluate the accuracy of (11)C-choline PET scans in defining dominant intraprostatic lesions (DILs) for radiotherapy target volume definition. Eight men with prostate cancer who had (11)C-choline PET scans prior to radical prostatectomy were studied. Several methods were used to contour the DIL on the PET scans: visual, PET Edge, Region Grow, absolute standardised uptake value (SUV) thresholds and percentage of maximum SUV thresholds. Prostatectomy specimens were sliced in the transverse plane and DILs were delineated on these by a pathologist. These were then compared with the PET scans. The accuracy of correlation was assessed by the Dice similarity coefficient (DSC) and the Youden index. The contouring method resulting in both the highest DSC and the highest Youden index was 60% of the maximum SUV (SUV(60%)), with values of 0.64 and 0.51, respectively. However SUV(60%) was not statistically significantly better than all of the other methods by either measure. Although not statistically significant, SUV(60%) resulted in the best correlation between (11)C-choline PET and pathology amongst all the methods studied. The degree of correlation shown here is consistent with previous studies that have justified using imaging for DIL radiotherapy target volume definition. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  11. Internal target volume for post-hysterectomy vaginal recurrences of cervical cancers during image-guided radiotherapy.

    PubMed

    Upasani, Maheshkumar N; Chopra, Supriya; Engineer, Reena; Mahantshetty, Umesh; Medhi, Seema; Mehta, Zubin; Shrivastava, Shyam K

    2015-10-01

    The outcome of post-surgical recurrences of cervical cancer may be improved through radiation dose escalation, which hinges on accurate identification and treatment of the target. The present study quantifies target motion during course of image-guided radiotherapy (IGRT) for vault cancers. All patients underwent planning CT simulation after bladder-filling protocol. A daily pre-treatment megavoltage CT was performed. All translations and rotations were recorded. Post-registration displacement of gross tumour volume (GTV) and centre of mass (COM) of GTV was independently recorded by two observers for fractions one to seven. Day 1 image sets served as reference images against which the displacements of COM were measured. We calculated the displacements of common volume (CV) and encompassing volume (EV) of GTV for both the observers. A total of 90 image data sets of 15 patients were available for evaluation. Individual patient GTV and average GTV by both the observers were comparable. The average shifts for EV were 2.4 mm [standard deviation (SD) ±1.2] in the mediolateral, 4.2 mm (SD ±2.8) in the anteroposterior and 4.0 mm (SD ±2.1) in superoinferior directions. Similarly, the average shifts for CV were 1.9 mm (SD ±0.6) in the mediolateral, 3.7 mm (SD ±2.7) in the anteroposterior and 4.4 mm (SD ±2.7) in superoinferior directions. Using Stroom's/van Herk's formula, the minimum recommended margins would be 4.5/5.2, 8.2/9.4 and 7.3/8.3 mm, respectively, for lateral, anteroposterior and superoinferior directions. Differential directional internal margin is recommended in patients undergoing IGRT for post-surgical recurrence of cervical cancers. Internal organ motion of vault cancers can be accounted for by a directional margin to the gross tumour.

  12. Target Volume Delineation in Oropharyngeal Cancer: Impact of PET, MRI, and Physical Examination

    SciTech Connect

    Thiagarajan, Anuradha; Caria, Nicola; Schoeder, Heiko; Iyer, N. Gopalakrishna; Wolden, Suzanne; Wong, Richard J.; Sherman, Eric; Fury, Matthew G.; Lee, Nancy

    2012-05-01

    Introduction: Sole utilization of computed tomography (CT) scans in gross tumor volume (GTV) delineation for head-and-neck cancers is subject to inaccuracies. This study aims to evaluate contributions of magnetic resonance imaging (MRI), positron emission tomography (PET), and physical examination (PE) to GTV delineation in oropharyngeal cancer (OPC). Methods: Forty-one patients with OPC were studied. All underwent contrast-enhanced CT simulation scans (CECTs) that were registered with pretreatment PETs and MRIs. For each patient, three sets of primary and nodal GTV were contoured. First, reference GTVs (GTVref) were contoured by the treating radiation oncologist (RO) using CT, MRI, PET, and PE findings. Additional GTVs were created using fused CT/PET scans (GTVctpet) and CT/MRI scans (GTVctmr) by two other ROs blinded to GTVref. To compare GTVs, concordance indices (CI) were calculated by dividing the respective overlap volumes by overall volumes. To evaluate the contribution of PE, composite GTVs derived from CT, MRI, and PET (GTVctpetmr) were compared with GTVref. Results: For primary tumors, GTVref was significantly larger than GTVctpet and GTVctmr (p < 0.001). Although no significant difference in size was noted between GTVctpet and GTVctmr (p = 0.39), there was poor concordance between them (CI = 0.62). In addition, although CI (ctpetmr vs. ref) was low, it was significantly higher than CI (ctpet vs. ref) and CI (ctmr vs. ref) (p < 0.001), suggesting that neither modality should be used alone. Qualitative analyses to explain the low CI (ctpetmr vs. ref) revealed underestimation of mucosal disease when GTV was contoured without knowledge of PE findings. Similar trends were observed for nodal GTVs. However, CI (ctpet vs. ref), CI (ctmr vs. ref), and CI (ctpetmr vs. ref) were high (>0.75), indicating that although the modalities were complementary, the added benefit was small in the context of CECTs. In addition, PE did not aid greatly in nodal GTV delineation

  13. Impact of targeted-volume ventilation on pulmonary dynamics in preterm infants with respiratory distress syndrome.

    PubMed

    Alkan Ozdemir, Senem; Arun Ozer, Esra; Ilhan, Ozkan; Sutcuoglu, Sumer

    2017-02-01

    Mechanical ventilation is an essential therapy in the treatment of respiratory failure in preterm infants. However, optimal ventilation strategy continues to be difficult to define. To compare the effects of volume guarantee (VG) combined with intermittent mandatory ventilation (SIMV) and VG combined with pressure support ventilation (PSV) on the pulmonary mechanics and short term prognosis in preterm infants with respiratory distress syndrome. Infants of <32 weeks gestational age ventilated for respiratory distress syndrome were randomized to receive either SIMV + VG or PSV + VG. The patient characteristics, ventilator variables including PIP, PEEP, MAP, VT, dynamic compliance, resistance, C20/C, and neonatal outcomes (IVH, ROP, oxygen dependency at 28th postnatal day and 36 weeks of PMA), mortality and extubation failure were recorded in each groups. Thirty-four infants were enrolled in to the study: 19 patients were randomized to the SIMV + VG group, and 15 patients to the PSV + VG group. No significant differences were observed between the two groups in terms of the birth weight, gestational age, gender, multiple pregnancy, delivery mode, and antenatal steroid treatment. The respiratory and ventilatory parameters were similar in the groups. The need for reintubation were common in SIMV + VG group (P < 0.01). Volume guaranteed ventilation combined with PSV may be a convenient method for preterm infants with RDS in terms of reducing postextubation atelectasis and the need for reintubation. Pediatr Pulmonol. 2017;52:213-216. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  14. Evaluation of internal target volume in patients undergoing image-guided intensity modulated adjuvant radiation for gastric cancers.

    PubMed

    Aggarwal, A; Chopra, S; Paul, S N; Engineer, R; Srivastava, S K

    2014-01-01

    To evaluate three-dimensional (3D) displacements of gastric remnant during adjuvant radiation. From January 2011 to September 2012, patients undergoing adjuvant image-guided intensity-modulated radiation on tomotherapy were included. Megavoltage CT (MVCT) data sets from daily treatment were coregistered with Day 1 MVCT. Residual stomach remnant was delineated on the data set, while the remaining were blinded to previous day contours. Gastric volume and centre of mass (COM) were determined for all data sets. The 3D deviation of COM was calculated for each fraction. Mean 3D and standard deviation (SD) were calculated for each patient and study population, and a 95% confidence interval (CI) was determined. Also, systematic and random errors for patient population and internal target volume (ITV) margin were calculated using the van Herk formula. There were 119 images available for 15 patients. Mean volume of remnant was 319 cm(3) (146-454 cm(3)). Gastric remnant expanded in different directions with no specific directional expansion. Average deviations in mediolateral, superoinferior and anteroposterior directions were 9 mm (3-25 mm; SD, 5 mm), 6 mm (3-16 mm; SD, 4 mm) and 5 mm (1-10 mm; SD, 3 mm), respectively, with 95% CI of 18, 15 and 11 mm, and ITV margins of 19.2, 13.5 and 7.8 mm, respectively. There is large variation in gastric remnant volume during the course of radiation. Large displacements observed in the present study necessitate the need to investigate adaptive techniques for optimizing intensity-modulated radiotherapy (IMRT) delivery. An adaptive strategy needs to be developed to optimize IMRT delivery for adjuvant gastric irradiation.

  15. Near-Millimeter Wave Technology Base Study: Volume I. Propagation and Target/Background Characteristics

    DTIC Science & Technology

    1979-11-01

    80%6) perc~entile deviation 2 1As ton truck 15.2 1229. 130. 80. 120. 116. 25 Data points; Dep ang~les: 3 to 9 deg Armored personnel 18.9 1546. 130...M60 tank - Honeywell -TARADCOM, Warren, ~ 36- and 94-GH&, Ftoreign armored Grass Georgia Instl. of Joint Army-AVr efforti tower- Aberdeen PG, MD pulked...ARRADCOM): Balistic Research Laboratory Propagation through aerosols (particularly smokes and Arthur LaGrange (BRL) obscurants) target/background signatures

  16. Hypervelocity Impact (HVI). Volume 3; WLE Small-Scale Fiberglass Panel Flat Target C-1

    NASA Technical Reports Server (NTRS)

    Gorman, Michael R.; Ziola, Steven M.

    2007-01-01

    During 2003 and 2004, the Johnson Space Center's White Sands Testing Facility in Las Cruces, New Mexico conducted hypervelocity impact tests on the space shuttle wing leading edge. Hypervelocity impact tests were conducted to determine if Micro-Meteoroid/Orbital Debris impacts could be reliably detected and located using simple passive ultrasonic methods. The objective of Target C-1 was to study hypervelocity impacts on the reinforced carbon-carbon (RCC) panels of the Wing Leading Edge. Fiberglass was used in place of RCC in the initial tests. Impact damage was detected using lightweight, low power instrumentation capable of being used in flight.

  17. Hypervelocity Impact (HVI). Volume 4; WLE Small-Scale Fiberglass Panel Flat Target C-2

    NASA Technical Reports Server (NTRS)

    Gorman, Michael R.; Ziola, Steven M.

    2007-01-01

    During 2003 and 2004, the Johnson Space Center's White Sands Testing Facility in Las Cruces, New Mexico conducted hypervelocity impact tests on the space shuttle wing leading edge. Hypervelocity impact tests were conducted to determine if Micro-Meteoroid/Orbital Debris impacts could be reliably detected and located using simple passive ultrasonic methods. The objective of Target C-2 was to study impacts through the reinforced carboncarbon (RCC) panels of the Wing Leading Edge. Fiberglass was used in place of RCC in the initial tests. Impact damage was detected using lightweight, low power instrumentation capable of being used in flight.

  18. Intensity modulated radiotherapy for high risk prostate cancer based on sentinel node SPECT imaging for target volume definition

    PubMed Central

    Ganswindt, Ute; Paulsen, Frank; Corvin, Stefan; Eichhorn, Kai; Glocker, Stefan; Hundt, Ilse; Birkner, Mattias; Alber, Markus; Anastasiadis, Aristotelis; Stenzl, Arnulf; Bares, Roland; Budach, Wilfried; Bamberg, Michael; Belka, Claus

    2005-01-01

    Background The RTOG 94-13 trial has provided evidence that patients with high risk prostate cancer benefit from an additional radiotherapy to the pelvic nodes combined with concomitant hormonal ablation. Since lymphatic drainage of the prostate is highly variable, the optimal target volume definition for the pelvic lymph nodes is problematic. To overcome this limitation, we tested the feasibility of an intensity modulated radiation therapy (IMRT) protocol, taking under consideration the individual pelvic sentinel node drainage pattern by SPECT functional imaging. Methods Patients with high risk prostate cancer were included. Sentinel nodes (SN) were localised 1.5–3 hours after injection of 250 MBq 99mTc-Nanocoll using a double-headed gamma camera with an integrated X-Ray device. All sentinel node localisations were included into the pelvic clinical target volume (CTV). Dose prescriptions were 50.4 Gy (5 × 1.8 Gy / week) to the pelvis and 70.0 Gy (5 × 2.0 Gy / week) to the prostate including the base of seminal vesicles or whole seminal vesicles. Patients were treated with IMRT. Furthermore a theoretical comparison between IMRT and a three-dimensional conformal technique was performed. Results Since 08/2003 6 patients were treated with this protocol. All patients had detectable sentinel lymph nodes (total 29). 4 of 6 patients showed sentinel node localisations (total 10), that would not have been treated adequately with CT-based planning ('geographical miss') only. The most common localisation for a probable geographical miss was the perirectal area. The comparison between dose-volume-histograms of IMRT- and conventional CT-planning demonstrated clear superiority of IMRT when all sentinel lymph nodes were included. IMRT allowed a significantly better sparing of normal tissue and reduced volumes of small bowel, large bowel and rectum irradiated with critical doses. No gastrointestinal or genitourinary acute toxicity Grade 3 or 4 (RTOG) occurred. Conclusion IMRT

  19. Impacts of ultra-low volume resmethrin applications on non-target insects.

    PubMed

    Oberhauser, Karen S; Manweiler, Stephen A; Lelich, Rosemary; Blank, Meredith; Batalden, Rebecca V; de Anda, Alma

    2009-03-01

    We studied the impacts of exposure to ultra-low volume (ULV) applications of resmethrin (Scourge) on monarch butterfly (Danaus plexippus) larvae and adults. In a series of 3 experiments, we measured short- and long-term survival of monarch larvae and adults, and the impacts of consuming previously exposed host plants on monarch larvae. We measured efficacy during all experiments with caged sentinel mosquitoes, and during Experiments 1 and 2 with pretreatment, treatment, and posttreatment measurements of mosquito abundance in CO2 traps. Downwind monarch larval and adult mortality were higher than upwind or control mortality up to 120 m, but not 170 m, from the spray path. In 1 experiment, monarchs exposed to spray as larvae developed into smaller adults, suggesting sublethal impacts. Milkweed host plants sprayed 1, but not 2 or 4 days previously, resulted in increased monarch larval mortality. Sentinel mosquito mortality was generally high, and CO2 traps revealed substantially lower mosquito abundance immediately after the treatment (>90% reduction) but <20% reduction 24 h after treatment. Our results suggest that ULV resmethrin applications will impact lepidopteran larvae and adults that are directly exposed to the spray but that generalizations about other nontarget taxa will require additional research. The magnitude of population-level impacts on monarchs will depend on the proportion of the population that is exposed.

  20. Target volume definition for upper abdominal irradiation using CT scans obtained during inhale and exhale phases.

    PubMed

    Aruga, T; Itami, J; Aruga, M; Nakajima, K; Shibata, K; Nojo, T; Yasuda, S; Uno, T; Hara, R; Isobe, K; Machida, N; Ito, H

    2000-09-01

    To evaluate the clinical utility of a treatment-planning technique involving the use of CT images obtained during both the static exhalation phase and static inhalation phase (two-phase planning). Ten patients with pancreatic or liver tumors underwent CT scanning under static exhale and inhale conditions, after a period of mild ventilation. By setting image positions differently, we were able to treat the two-phase images as one dataset. Each gross tumor volume (GTV) was contoured separately and the mixed GTV was used for the two-phase treatment planning. Treatment plans were constructed to compare the two-phase plans with the plans constructed using static exhalation images. The shift of the center of the GTV and kidneys and the minimum dose of GTV were then calculated. The shift of the GTV ranged from 2.6 to 27. 3 mm and that of the kidneys from 2.2 to 24 mm. In some patients whose treatment was planned using exhalation planning, the minimum dose of GTV at inhalation was less than 90% of the isocenter dose. Two-phase planning is a simple technique that can visualize tumor and organ movement simultaneously using CT. It further defines adequate field margins around the tumor and prevents unexpected radiation exposure to critical organs. Routine use of this technique for upper abdominal irradiation is recommended.

  1. The ADVANCE project: Formal evaluation of the targeted deployment. Volume 3

    SciTech Connect

    1997-01-01

    ADVANCE [Advanced Driver and Vehicle Advisory Navigation ConcEpt] was a public/private partnership conceived and developed by four founding parties. The founding parties include the Federal Highway Administration (FHWA), the Illinois Department of Transportation (IDOT), the University of Illinois at Chicago and Northwestern University operating together under the auspices of the Illinois Universities Transportation Research Consortium (IUTRC), and Motorola, Inc. The major responsibilities of each party are fully described in the Project agreement. Subsequently, these four were joined on the Steering Committee by the American Automobile Association (AAA). This unique blending of public sector, private sector and university interests, augmented by more than two dozen other private sector participants, provided a strong set of resources for ADVANCE. The ADVANCE test area covered over 300 square miles including portions of the City of Chicago and 40 northwest suburban communities. The Project encompasses the high growth areas adjacent to O`Hare International Airport, the Schaumbura/Hoffman Estates office and retail complexes, and the Lake-Cook Road development corridor. It also includes major sports and entertainment complexes such as the Arlington International Racecourse and the Rosemont Horizon. The population in the area is more than 750,000. This volume provides a summary of the insights and achievements made as a result of this field test, and selected appendices containing more detailed information.

  2. Comparison of planning target volumes based on three-dimensional and four-dimensional CT imaging of thoracic esophageal cancer.

    PubMed

    Wang, Wei; Li, Jianbin; Zhang, Yingjie; Shao, Qian; Xu, Min; Fan, Tingyong; Wang, Jinzhi

    2016-01-01

    To investigate the definition of planning target volumes (PTVs) based on four-dimensional computed tomography (4DCT) compared with conventional PTV definition and PTV definition using asymmetrical margins for thoracic primary esophageal cancer. Forty-three patients with esophageal cancer underwent 3DCT and 4DCT simulation scans during free breathing. The motions of primary tumors located in the proximal (group A), middle (group B), and distal (group C) thoracic esophagus were obtained from the 4DCT scans. PTV3D was defined on 3DCT using the tumor motion measured based on 4DCT, PTV conventional (PTVconv) was defined on 3DCT by adding a 1.0 cm margin to the clinical target volume, and PTV4D was defined as the union of the target volumes contoured on the ten phases of the 4DCT images. The centroid positions, volumetric differences, and dice similarity coefficients were evaluated for all PTVs. The median centroid shifts between PTV3D and PTV4D and between PTVconv and PTV4D in all three dimensions were <0.3 cm for the three groups. The median size ratios of PTV4D to PTV3D were 0.80, 0.88, and 0.71, and PTV4D to PTVconv were 0.67, 0.73, and 0.76 (χ (2)=-3.18, -2.98, and -3.06; P=0.001, 0.003, and 0.002) for groups A, B, and C, respectively. The dice similarity coefficients were 0.87, 0.90, and 0.81 between PTV4D and PTV3D and 0.80, 0.84, and 0.83 between PTV4D and PTVconv (χ (2) =-3.18, -2.98, and -3.06; P=0.001, 0.003, and 0.002) for groups A, B, and C, respectively. The difference between the degree of inclusion of PTV4D in PTV3D and that of PTV4D in PTVconv was <2% for all groups. Compared with PTVconv, the amount of irradiated normal tissue for PTV3D was decreased by 11.81% and 11.86% in groups A and B, respectively, but was increased by 2.93% in group C. For proximal and middle esophageal cancer, 3DCT-based PTV using asymmetrical margins provides good coverage of PTV4D; however, for distal esophageal cancer, 3DCT-based PTV using conventional margins provides ideal

  3. Water-filled balloon in the postoperative resection cavity improves dose distribution to target volumes in radiotherapy of maxillary sinus carcinoma

    PubMed Central

    Zhang, Qun; Lin, Shi-Rong; He, Fang; Kang, De-Hua; Chen, Guo-Zhang; Luo, Wei

    2011-01-01

    Postoperative radiotherapy is a major treatment for patients with maxillary sinus carcinoma. However, the irregular resection cavity poses a technical difficulty for this treatment, causing uneven dose distribution to target volumes. In this study, we evaluated the dose distribution to target volumes and normal tissues in postoperative intensity-modulated radiotherapy (IMRT) after placing a water-filled balloon into the resection cavity. Three postoperative patients with advanced maxillary sinus carcinoma were selected in this trial. Water-filled balloons and supporting dental stents were fabricated according to the size of the maxillary resection cavity. Simulation CT scans were performed with or without water-filled balloons, IMRT treatment plans were established, and dose distribution to target volumes and organs at risk were evaluated. Compared to those in the treatment plan without balloons, the dose (D98) delivered to 98% of the gross tumor volume (GTV) increased by 2.1 Gy (P = 0.009), homogeneity index (HI) improved by 2.3% (P = 0.001), and target volume conformity index (TCI) of 68 Gy increased by 18.5% (P = 0.011) in the plan with balloons. Dosimetry endpoints of normal tissues around target regions in both plans were not significantly different (P > 0.05) except for the optic chiasm. In the plan without balloons, 68 Gy high-dose regions did not entirely cover target volumes in the ethmoid sinus, posteromedial wall of the maxillary sinus, or surgical margin of the hard palate. In contrast, 68 Gy high-dose regions entirely covered the GTV in the plan with balloons. These results suggest that placing a water-filled balloon in the resection cavity for postoperative IMRT of maxillary sinus carcinoma can reduce low-dose regions and markedly and simultaneously increase dose homogeneity and conformity of target volumes. PMID:22035860

  4. SU-E-J-75: Importance of 4DCT for Target Volume Definition in Stereotactic Lung Radiotherapy

    SciTech Connect

    Goksel, E; Cone, D; Kucucuk, H; Senkesen, O; Yilmaz, M; Aslay, I; Tezcanli, E; Garipagaoglu, M; Sengoz, M

    2014-06-01

    Purpose: We aimed to investigate the importance of 4DCT for lung tumors treated with SBRT and whether maximum intensity projection (MIP) and free breathing (FB) images can compansate for tumor movement. Methods: Six patients with primary lung cancer and 2 patients with lung metastasis with a median age of 69.5 (42–86) were included. Patients were positioned supine on a vacuum bag. In addition to FB planning CT images, 4DCT images were obtained at 3 mm intervals using Varian RPM system with (Siemens Somatom Sensetion 64). MIP series were reconstructed using 4DCT images. PTV-FB and PTV-MIP (GTV+5mm) volumes were contoured using FB and MIP series, respectively. GTVs were defined on each of eight different breathing phase images and were merged to create the ITV. PTV-4D was generated with a 5 mm margin to ITV. PTV-MIP and PTV-4D contours were copied to FB CT series and treatment plans for PTV-MIP and PTV-FB were generated using RapidArc (2 partial arc) technique in Eclipse (version 11, AAA algorithm). The prescription dose was 5600cGy in 7 fractions. ITV volumes receiving prescription dose (%) and V95 for ITV were calculated for each treatment plan. Results: The mean PTV-4B, PTV-MIP and PTV-FB volumes were 23.2 cc, 15.4cc ve 11cc respectively. Median volume of ITV receiving the prescription dose was 34.6% (16.4–70 %) and median V95 dose for ITV was 1699cGy (232cGy-5117cGy) in the plan optimized for PTV-FB as the reference. When the plan was optimized for PTV-MIP, median ITV volume receiving the prescription dose was 67.15% (26–86%) and median V95 dose for ITV was 4231cGy (1735cGy-5290cGy). Conclusion: Images used in lung SBRT are critical for treatment quality; FB and MIP images did not compensate target movement, therefore 4DCT images should be obtained for all patients undergoing lung SBRT or the safety margins should be adjusted.

  5. Superior target volume and organ stability with the use of endorectal balloons in post-prostatectomy radiotherapy.

    PubMed

    de Leon, Jeremiah F; Jameson, Michael G; Windsor, Apsara; Cloak, Kirrily; Keats, Sarah; Vial, Philip; Holloway, Lois; Metcalfe, Peter; Sidhom, Mark

    2015-08-01

    We investigated the endorectal balloon (ERB) as a method to improve post-prostatectomy clinical target volume (CTV) stability. Seventy cone-beam CT (CBCT) obtained during radiotherapy treatment from seven patients treated with an ERB and 68 CBCT from seven patients treated without an ERB were contoured according to published guidelines. CTV was subdivided into superior and inferior CTV; whole rectal volume was subdivided into superior and inferior rectum and anal volume. Concordance index (CI) of CBCT treatment volumes compared with planning volumes was calculated and displacements were measured. Whole rectal, superior and inferior rectum and anal CI were significantly improved with the ERB by 21%, 17%, 26% and 17% respectively (P < 0.0001). Overall CTV and inferior CTV CI was improved by 4% with the ERB (overall CTV P = 0.021; Inferior CTV P < 0.0001). In the ERB cohort, average displacement for superior CTV was 0.37 cm anterior-posterior (AP) and 0.10 cm left-right (LR). Average standard deviation was 0.27 cm AP and 0.11 cm LR. Inferior CTV average displacement was 0.11 cm AP and 0.02 cm LR. Average standard deviation was 0.11 cm AP and 0.02 cm LR. In the non-ERB cohort, average displacement for superior CTV was 0.43 cm AP and 0.10 mm left-right (LR). Average standard deviation was 0.45 cm AP and 0.13 cm LR. Inferior CTV average displacement was 0.16 cm AP and 0.01 cm LR. Average standard deviation was 0.17 cm AP and 0.03 cm LR. There was no statistically significant impact of bladder filling on CTV CI in ERB patients (P = 0.551) as opposed to non-ERB patients (P = 0.0421). ERBs in the post-prostatectomy setting resulted in increased rectal and CTV stability while negating the effects of bladder filling on CTV stability. © 2015 The Royal Australian and New Zealand College of Radiologists.

  6. Are we ready for positron emission tomography/computed tomography-based target volume definition in lymphoma radiation therapy?

    PubMed

    Yeoh, Kheng-Wei; Mikhaeel, N George

    2013-01-01

    Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has become indispensable for the clinical management of lymphomas. With consistent evidence that it is more accurate than anatomic imaging in the staging and response assessment of many lymphoma subtypes, its utility continues to increase. There have therefore been efforts to incorporate PET/CT data into radiation therapy decision making and in the planning process. Further, there have also been studies investigating target volume definition for radiation therapy using PET/CT data. This article will critically review the literature and ongoing studies on the above topics, examining the value and methods of adding PET/CT data to the radiation therapy treatment algorithm. We will also discuss the various challenges and the areas where more evidence is required. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Are We Ready for Positron Emission Tomography/Computed Tomography-based Target Volume Definition in Lymphoma Radiation Therapy?

    SciTech Connect

    Yeoh, Kheng-Wei; Mikhaeel, N. George

    2013-01-01

    Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has become indispensable for the clinical management of lymphomas. With consistent evidence that it is more accurate than anatomic imaging in the staging and response assessment of many lymphoma subtypes, its utility continues to increase. There have therefore been efforts to incorporate PET/CT data into radiation therapy decision making and in the planning process. Further, there have also been studies investigating target volume definition for radiation therapy using PET/CT data. This article will critically review the literature and ongoing studies on the above topics, examining the value and methods of adding PET/CT data to the radiation therapy treatment algorithm. We will also discuss the various challenges and the areas where more evidence is required.

  8. Planning target volume margins for prostate radiotherapy using daily electronic portal imaging and implanted fiducial markers

    PubMed Central

    2010-01-01

    Background Fiducial markers and daily electronic portal imaging (EPI) can reduce the risk of geographic miss in prostate cancer radiotherapy. The purpose of this study was to estimate CTV to PTV margin requirements, without and with the use of this image guidance strategy. Methods 46 patients underwent placement of 3 radio-opaque fiducial markers prior to prostate RT. Daily pre-treatment EPIs were taken, and isocenter placement errors were corrected if they were ≥ 3 mm along the left-right or superior-inferior axes, and/or ≥ 2 mm along the anterior-posterior axis. During-treatment EPIs were then obtained to estimate intra-fraction motion. Results Without image guidance, margins of 0.57 cm, 0.79 cm and 0.77 cm, along the left-right, superior-inferior and anterior-posterior axes respectively, are required to give 95% probability of complete CTV coverage each day. With the above image guidance strategy, these margins can be reduced to 0.36 cm, 0.37 cm and 0.37 cm respectively. Correction of all isocenter placement errors, regardless of size, would permit minimal additional reduction in margins. Conclusions Image guidance, using implanted fiducial markers and daily EPI, permits the use of narrower PTV margins without compromising coverage of the target, in the radiotherapy of prostate cancer. PMID:20537161

  9. Dosimetric evaluation of planning target volume margin reduction for prostate cancer via image-guided intensity-modulated radiation therapy

    NASA Astrophysics Data System (ADS)

    Hwang, Taejin; Kang, Sei-Kwon; Cheong, Kwang-Ho; Park, Soah; Yoon, Jai-Woong; Han, Taejin; Kim, Haeyoung; Lee, Meyeon; Kim, Kyoung-Joo; Bae, Hoonsik; Suh, Tae-Suk

    2015-07-01

    The aim of this study was to quantitatively estimate the dosimetric benefits of the image-guided radiation therapy (IGRT) system for the prostate intensity-modulated radiation therapy (IMRT) delivery. The cases of eleven patients who underwent IMRT for prostate cancer without a prostatectomy at our institution between October 2012 and April 2014 were retrospectively analyzed. For every patient, clinical target volume (CTV) to planning target volume (PTV) margins were uniformly used: 3 mm, 5 mm, 7 mm, 10 mm, 12 mm, and 15 mm. For each margin size, the IMRT plans were independently optimized by one medical physicist using Pinnalce3 (ver. 8.0.d, Philips Medical System, Madison, WI) in order to maintain the plan quality. The maximum geometrical margin (MGM) for every CT image set, defined as the smallest margin encompassing the rectum at least at one slice, was between 13 mm and 26 mm. The percentage rectum overlapping PTV (%V ROV ), the rectal normal tissue complication probability (NTCP) and the mean rectal dose (%RD mean ) increased in proportion to the increase of PTV margin. However the bladder NTCP remained around zero to some extent regardless of the increase of PTV margin while the percentage bladder overlapping PTV (%V BOV ) and the mean bladder dose (%BD mean ) increased in proportion to the increase of PTV margin. Without relatively large rectum or small bladder, the increase observed for rectal NTCP, %RDmean and %BD mean per 1-mm PTV margin size were 1.84%, 2.44% and 2.90%, respectively. Unlike the behavior of the rectum or the bladder, the maximum dose on each femoral head had little effect on PTV margin. This quantitative study of the PTV margin reduction supported that IG-IMRT has enhanced the clinical effects over prostate cancer with the reduction of normal organ complications under the similar level of PTV control.

  10. Cranial location of level II lymph nodes in laryngeal cancer: Implications for elective nodal target volume delineation

    SciTech Connect

    Braam, Petra M. . E-mail: P.M.Braam@umcutrecht.nl; Raaijmakers, Cornelis P.J.; Terhaard, Chris

    2007-02-01

    Purpose: To analyze the cranial distribution of level II lymph nodes in patients with laryngeal cancer to optimize the elective radiation nodal target volume delineation. Methods and Materials: The most cranially located metastatic lymph node was delineated in 67 diagnostic CT data sets. The minimum distance from the base of the skull (BOS) to the lymph node was determined. Results: A total of 98 lymph nodes were delineated including 62 ipsilateral and 36 contralateral lymph nodes. The mean ipsilateral and contralateral distance from the top of the most cranial metastatic lymph node to the BOS was 36 mm (range, -9-120; standard deviation [SD], 17.9) and 35 mm (range, 14-78; SD 15.0), respectively. Only 5% and 12% of the ipsilateral and 3% and 9% of the contralateral metastatic lymph nodes were located within 15 mm and 20 mm below the BOS, respectively. No significant differences were found between patients with only ipsilateral metastatic lymph nodes and patients with bilateral metastatic lymph nodes. Between tumors that do cross the midline and those that do not, no significant difference was found in the distance of the most cranial lymph node to the BOS and the occurrence ipsilateral or contralateral. Conclusions: Setting the cranial border of the nodal target volume 1.5 cm below the base of the skull covers 95% of the lymph nodes and should be considered in elective nodal irradiation for laryngeal cancer. Bilateral neck irradiation is mandatory, including patients with unilateral laryngeal cancer, when elective irradiation is advised.

  11. Sci—Fri AM: Mountain — 06: Optimizing planning target volume in lung radiotherapy using deformable registration

    SciTech Connect

    Hoang, P; Wierzbicki, M

    2014-08-15

    A four dimensional computed tomography (4DCT) image is acquired for all radically treated, lung cancer patients to define the internal target volume (ITV), which encompasses tumour motion due to breathing and subclinical disease. Patient set-up error and anatomical motion that is not due to breathing is addressed through an additional 1 cm margin around the ITV to obtain the planning target volume (PTV). The objective of this retrospective study is to find the minimum PTV margin that provides an acceptable probability of delivering the prescribed dose to the ITV. Acquisition of a kV cone beam computed tomography (CBCT) image at each fraction was used to shift the treatment couch to accurately align the spinal cord and carina. Our method utilized deformable image registration to automatically position the planning ITV on each CBCT. We evaluated the percentage of the ITV surface that fell within various PTVs for 79 fractions across 18 patients. Treatment success was defined as a situation where at least 99% of the ITV is covered by the PTV. Overall, this is to be achieved in at least 90% of the treatment fractions. The current approach with a 1cm PTV margin was successful ∼96% of the time. This analysis revealed that the current margin can be reduced to 0.8cm isotropic or 0.6×0.6×1 cm{sup 3} non-isotropic, which were successful 92 and 91 percent of the time respectively. Moreover, we have shown that these margins maintain accuracy, despite intrafractional variation, and maximize CBCT image guidance capabilities.

  12. Internal target volume for post-hysterectomy vaginal recurrences of cervical cancers during image-guided radiotherapy

    PubMed Central

    Upasani, Maheshkumar N; Engineer, Reena; Mahantshetty, Umesh; Medhi, Seema; Mehta, Zubin; Shrivastava, Shyam K

    2015-01-01

    Objective: The outcome of post-surgical recurrences of cervical cancer may be improved through radiation dose escalation, which hinges on accurate identification and treatment of the target. The present study quantifies target motion during course of image-guided radiotherapy (IGRT) for vault cancers. Methods: All patients underwent planning CT simulation after bladder-filling protocol. A daily pre-treatment megavoltage CT was performed. All translations and rotations were recorded. Post-registration displacement of gross tumour volume (GTV) and centre of mass (COM) of GTV was independently recorded by two observers for fractions one to seven. Day 1 image sets served as reference images against which the displacements of COM were measured. We calculated the displacements of common volume (CV) and encompassing volume (EV) of GTV for both the observers. Results: A total of 90 image data sets of 15 patients were available for evaluation. Individual patient GTV and average GTV by both the observers were comparable. The average shifts for EV were 2.4 mm [standard deviation (SD) ±1.2] in the mediolateral, 4.2 mm (SD ±2.8) in the anteroposterior and 4.0 mm (SD ±2.1) in superoinferior directions. Similarly, the average shifts for CV were 1.9 mm (SD ±0.6) in the mediolateral, 3.7 mm (SD ±2.7) in the anteroposterior and 4.4 mm (SD ±2.7) in superoinferior directions. Using Stroom's/van Herk's formula, the minimum recommended margins would be 4.5/5.2, 8.2/9.4 and 7.3/8.3 mm, respectively, for lateral, anteroposterior and superoinferior directions. Conclusion: Differential directional internal margin is recommended in patients undergoing IGRT for post-surgical recurrence of cervical cancers. Advances in knowledge: Internal organ motion of vault cancers can be accounted for by a directional margin to the gross tumour. PMID:26248870

  13. Variability in clinical target volume delineation for intensity modulated radiation therapy in 3 challenging cervix cancer scenarios.

    PubMed

    Lim, Karen; Erickson, Beth; Jürgenliemk-Schulz, Ina M; Gaffney, David; Creutzberg, Carien L; Viswanathan, Akila; Portelance, Lorraine; Beriwal, Sushil; Wolfson, Aaron; Bosch, Walter; De Los Santos, Jennifer; Yashar, Catheryn; Jhingran, Anuja; Varia, Mahesh; El Naqa, Issam; King, Bronwyn; Fyles, Anthony

    2015-01-01

    The purpose of this study was to assess variability in contouring the gross tumor volume (GTV) and clinical target volume (CTV) of 3 clinical cervix cancer cases by a cohort of international experts in the field in preparation for the development of an online teaching atlas. Twelve international experts participated. Three clinical scenarios: node positivity (PLN), retroverted uterus (RV), and parametrial invasion (PI) were used. Sagittal and axial magnetic resonance images of the clinical cases were downloaded to participants' treatment planning systems for contouring. The GTV/cervix/uterus/parametria/vagina and nodal CTV were contoured. Contour consensus was assessed for sensitivity/specificity using an expectation maximization algorithm called Simultaneous Truth and Performance Level Estimation and experts' overall agreement was summarized by kappa statistics. Agreement for GTV in the 3 clinical cases was high (Simultaneous Truth and Performance Level Estimation sensitivity, 0.54-0.92; specificity, 0.97-0.98; and kappa measure for PLN, RV, and PI was 0.86, 0.76, and 0.42; P < .0001). Moderate to substantial agreement was seen for nodal CTV (kappa statistics for PLN, RV, and PI was 0.65, 0.58, and 0.62; P < .0001), uterus (kappa for PLN, RV, and PI was 0.45, 0.74, and 0.77; P < .0001), and parametria (kappa for PLN, RV, and PI was 0.49, 0.62, and 0.50; P < .0001). Contouring heterogeneity was greatest for the cervix (kappa measure for PLN, RV, and PI was 0.15, 0.4, and 0.24; P < .0001) and vagina (kappa for PLN, RV, and PI was 0.47, 0.36 and 0.46; P < .0001), reflecting difficulties in determining the interface between GTV and these tissues. Kappa statistics of the different CTV components generally demonstrated moderate to substantial agreement among international experts in the field of gynecological radiation therapy. Further planning target volume margins accounting for organ motion and setup errors are a necessary addition to the CTV. Copyright © 2015

  14. Defining the Optimal Planning Target Volume in Image-Guided Stereotactic Radiosurgery of Brain Metastases: Results of a Randomized Trial

    SciTech Connect

    Kirkpatrick, John P.; Wang, Zhiheng; Sampson, John H.; McSherry, Frances; Herndon, James E.; Allen, Karen J.; Duffy, Eileen; Hoang, Jenny K.; Chang, Zheng; Yoo, David S.; Kelsey, Chris R.; Yin, Fang-Fang

    2015-01-01

    Purpose: To identify an optimal margin about the gross target volume (GTV) for stereotactic radiosurgery (SRS) of brain metastases, minimizing toxicity and local recurrence. Methods and Materials: Adult patients with 1 to 3 brain metastases less than 4 cm in greatest dimension, no previous brain radiation therapy, and Karnofsky performance status (KPS) above 70 were eligible for this institutional review board–approved trial. Individual lesions were randomized to 1- or 3- mm uniform expansion of the GTV defined on contrast-enhanced magnetic resonance imaging (MRI). The resulting planning target volume (PTV) was treated to 24, 18, or 15 Gy marginal dose for maximum PTV diameters less than 2, 2 to 2.9, and 3 to 3.9 cm, respectively, using a linear accelerator–based image-guided system. The primary endpoint was local recurrence (LR). Secondary endpoints included neurocognition Mini-Mental State Examination, Trail Making Test Parts A and B, quality of life (Functional Assessment of Cancer Therapy-Brain), radionecrosis (RN), need for salvage radiation therapy, distant failure (DF) in the brain, and overall survival (OS). Results: Between February 2010 and November 2012, 49 patients with 80 brain metastases were treated. The median age was 61 years, the median KPS was 90, and the predominant histologies were non–small cell lung cancer (25 patients) and melanoma (8). Fifty-five, 19, and 6 lesions were treated to 24, 18, and 15 Gy, respectively. The PTV/GTV ratio, volume receiving 12 Gy or more, and minimum dose to PTV were significantly higher in the 3-mm group (all P<.01), and GTV was similar (P=.76). At a median follow-up time of 32.2 months, 11 patients were alive, with median OS 10.6 months. LR was observed in only 3 lesions (2 in the 1 mm group, P=.51), with 6.7% LR 12 months after SRS. Biopsy-proven RN alone was observed in 6 lesions (5 in the 3-mm group, P=.10). The 12-month DF rate was 45.7%. Three months after SRS, no significant change in

  15. Variation in radiotherapy target volume definition, dose to organs at risk and clinical target volumes using anatomic (computed tomography) versus combined anatomic and molecular imaging (positron emission tomography/computed tomography): intensity-modulated radiotherapy delivered using a tomotherapy Hi Art machine: final results of the VortigERN study.

    PubMed

    Chatterjee, S; Frew, J; Mott, J; McCallum, H; Stevenson, P; Maxwell, R; Wilsdon, J; Kelly, C G

    2012-12-01

    Contrast-enhanced computed tomography (CECT) is the current standard for delineating tumours of the head and neck for radiotherapy. Although metabolic imaging with positron emission tomography (PET) has been used in recent years, the studies were non-confirmatory in establishing its routine role in radiotherapy planning in the modern era. This study explored the difference in gross tumour volume and clinical target volume definitions for the primary and nodal volumes when FDG PET/CT was used as compared with CECT in oropharyngeal cancer cases. Twenty patients with oropharyngeal cancers had a PET/CT scan in the treatment position after consent. Target volumes were defined on CECT scans by a consultant clinical oncologist who was blind to the PET scans. After obtaining inputs from a radiologist, another set of target volumes were outlined on the PET/CT data set. The gross and clinical target volumes as defined on the two data sets were then analysed. The hypothesis of more accurate target delineation, preventing geographical miss and comparative overlap volumes between CECT and PET/CT, was explored. The study also analysed the volumes of intersection and analysed whether there was any TNM stage migration when PET/CT was used as compared with CECT for planning. In 17 of 20 patients, the TNM stage was not altered when adding FDG PET information to CT. PET information prevented geographical miss in two patients and identified distant metastases in one case. PET/CT gross tumour volumes were smaller than CECT volumes (mean ± standard deviation: 25.16 cm(3) ± 35.8 versus 36.56 cm(3) ± 44.14; P < 0.015) for the primary tumour. Interestingly, our study showed no significant differences in gross tumour volume for T1/T2 disease, although differences in gross tumour volumes for advanced disease (T3/T4) were significant. The nodal target volumes (mean ± standard deviation: CECT versus PET/CT 32.48 cm(3) ± 36.63 versus 32.21 cm(3) ± 37.09; P > 0.86) were not statistically

  16. Impact of (18)F-Fluciclovine PET on Target Volume Definition for Postprostatectomy Salvage Radiotherapy: Initial Findings from a Randomized Trial.

    PubMed

    Jani, Ashesh B; Schreibmann, Eduard; Rossi, Peter J; Shelton, Joseph; Godette, Karen; Nieh, Peter; Master, Viraj A; Kucuk, Omer; Goodman, Mark; Halkar, Raghuveer; Cooper, Sherrie; Chen, Zhengjia; Schuster, David M

    2017-03-01

    The purpose of this study was to evaluate the role of the synthetic amino acid PET radiotracer (18)F-fluciclovine in modifying the defined clinical and treatment-planning target volumes in postprostatectomy patients undergoing salvage radiotherapy and to evaluate the resulting dosimetric consequences to surrounding organs at risk. Methods: Ninety-six patients were enrolled in a randomized, prospective intention-to-treat clinical trial for potential salvage radiotherapy for recurrent prostate cancer after prostatectomy. The initial treatment plan was based on the results from conventional abdominopelvic CT and MRI. The 45 patients in the experimental arm also underwent abdominopelvic (18)F-fluciclovine PET/CT, and the images were registered with the conventional images to determine whether the results would modify the initial treatment plan. The 51 patients in the control arm did not undergo (18)F-fluciclovine PET/CT. For each patient, the clinical and treatment-planning target volumes that would have been treated before (18)F-fluciclovine registration were compared with those after registration. For organs at risk (rectum, bladder, and penile bulb), the volumes receiving 40 Gy and 65 Gy before registration were compared with those after registration. Statistical comparisons were made using the paired t test. Acute genitourinary and gastrointestinal toxicity as defined by the Radiation Therapy Oncology Group was compared between the control and experimental arms using the χ(2) test. Results: In 24 cases, radiotherapy was planned to a clinical target volume consisting of the prostate bed alone (CTV) (64.8-66.6 Gy). In 21 cases, radiotherapy was planned to a clinical target volume consisting of the pelvis (CTV1) (45.0 Gy) followed by a boost to the prostate bed (CTV2) (19.8-25.2 Gy). In each case, the respective treatment-planning target volume expansion (PTV, PTV1, or PTV2) was 0.8 cm (0.6 cm posterior). With the exception of PTV2, all postregistration volumes were

  17. High dose and compartmental target volume may improve patient outcome after radiotherapy for pelvic bone metastases from hepatocellular carcinoma

    PubMed Central

    Kim, Taehyung; Cha, Hye Jung; Kim, Jun Won; Seong, Jinsil; Lee, Ik Jae

    2016-01-01

    Purpose Pelvic bone metastases are difficult to treat because of complex pelvic bone anatomy and the proximity of normal organs. The adequacy of radiation dose and field coverage was evaluated. Patients and methods We analyzed 146 cases of pelvic bone metastases from HCC treated with radiotherapy (RT). Bone metastases were confirmed using CT/MRI. Subjective pain response was assessed using the visual analogue scale, and treatment-related toxicity with the Common Terminology Criteria for Adverse Events v3.0. Local failure free survival (LFFS) and overall survival were estimated using the Kaplan-Meier method. Results The local control rate was 80.1% and the pain control rate was 68.5%. Compartmental target volume (CTV), encompassing the whole compartment of the involved bone, was found to be a significant factor (1-year LFFS, 78% vs. 50%; p=0.001). Sites of metastasis were categorized as either upper or lower pelvic bone; both categories showed improved local control with CTV. Metastatic lesions that received more than 50 Gy of EQD2 showed more partial response in pain after RT (58% vs. 79%; p=0.007). No patient showed toxicity higher than Grade IV. Conclusion Compartmental RT targeted to the involved bone was associated with improved local control and LFFS. High-dose radiation was associated with an improved treatment response. PMID:27259272

  18. Intensity targeted radial structure tensor analysis and its application for automated mediastinal lymph node detection from CT volumes

    NASA Astrophysics Data System (ADS)

    Oda, Hirohisa; Nimura, Yukitaka; Oda, Masahiro; Kitasaka, Takayuki; Iwano, Shingo; Honma, Hirotoshi; Takabatake, Hirotsugu; Mori, Masaki; Natori, Hiroshi; Mori, Kensaku

    2016-03-01

    This paper presents a new blob-like enhancement filter based on Intensity Targeted Radial Structure Tensor (ITRST) analysis to improve mediastinal lymph node detection from chest CT volumes. Blob-like structure enhancement filter based on Radial Structure Tensor (RST) analysis can be utilized for initial detection of lymph node candidate regions. However, some of lymph nodes cannot be detected because RST analysis is influenced by neighboring regions whose intensity is very high or low, such as contrast-enhanced blood vessels and air. To overcome the problem, we propose ITRST analysis that integrate the prior knowledge on detection target intensity into RST analysis. Our lymph node detection method consists of two steps. First, candidate regions are obtained by ITRST analysis. Second, false positives (FPs) are removed by the Support Vector Machine (SVM) classifier. We applied the proposed method to 47 cases. Among 19 lymph nodes whose short axis is no less than 10 mm, 100.0 % of them were detected with 247.7 FPs/case by ITRST analysis, while only 80.0 % were detected with 123.0 FPs/case by RST analysis. After the false positive (FP) reduction by SVM, ITRST analysis outperformed RST analysis in lymph node detection performance.

  19. Investigation on the role of integrated PET/MRI for target volume definition and radiotherapy planning in patients with high grade glioma.

    PubMed

    Navarria, Pierina; Reggiori, Giacomo; Pessina, Federico; Ascolese, Anna Maria; Tomatis, Stefano; Mancosu, Pietro; Lobefalo, Francesca; Clerici, Elena; Lopci, Egesta; Bizzi, Alberto; Grimaldi, Marco; Chiti, Arturo; Simonelli, Matteo; Santoro, Armando; Bello, Lorenzo; Scorsetti, Marta

    2014-09-01

    To evaluate the impact of fluid-attenuated-inversion-recovery MRI (FLAIR/MRI) and Carbon-11-labeled-methionine PET (11C-MET-PET) on high grade glioma (HGG) tumor volume delineation for radiotherapy planning. Sixty-nine patients with HGG were evaluated. The clinical target volumes (CTV1, generated by adding a 10mm margin to FLAIRMRI area, CTV2 by adding a 20mm margin to enhanced T1MRI) and biological target volume (BTV) were delineated on pre-operative MRI images and 11CMETPET respectively. The overlap between CTV1 and CTV2 showed a low correlation between the two volumes with CTV1 not always fully included into the CTV2. In all cases the whole BTV was included into the CTV1, while in 35/69 patients (50%) part of BTV was outside the CTV2 despite larger margins were added. In all cases recurrences were within the CTV1 volume and in 19/38 (50%) partially outside the CTV2. In all patients relapse corresponded to the BTV area. Our data suggest that the target volume definition using FLAIR-MRI is more adequate compared to enhanced T1MRI. 11C-METPET uptake could help identify microscopic residual areas. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. Residual Tumor After Neoadjuvant Chemoradiation Outside the Radiation Therapy Target Volume: A New Prognostic Factor for Survival in Esophageal Cancer

    SciTech Connect

    Muijs, Christina; Smit, Justin; Karrenbeld, Arend; Beukema, Jannet; Mul, Veronique; Dam, Go van; Hospers, Geke; Kluin, Phillip; Langendijk, Johannes; Plukker, John

    2014-03-15

    Purpose/Objective(s): The aim of this study was to analyze the accuracy of gross tumor volume (GTV) delineation and clinical target volume (CTV) margins for neoadjuvant chemoradiation therapy (neo-CRT) in esophageal carcinoma at pathologic examination and to determine the impact on survival. Methods and Materials: The study population consisted of 63 esophageal cancer patients treated with neo-CRT. GTV and CTV borders were demarcated in situ during surgery on the esophagus, using anatomical reference points to provide accurate information regarding tumor location at pathologic evaluation. To identify prognostic factors for disease-free survival (DFS) and overall survival (OS), a Cox regression analysis was performed. Results: After resection, macroscopic residual tumor was found outside the GTV in 7 patients (11%). Microscopic residual tumor was located outside the CTV in 9 patients (14%). The median follow-up was 15.6 months. With multivariate analysis, only microscopic tumor outside the CTV (hazard ratio [HR], 4.96; 95% confidence interval [CI], 1.03-15.36), and perineural growth (HR, 5.77; 95% CI, 1.27-26.13) were identified as independent prognostic factors for OS. The 1-year OS was 20% for patients with tumor outside the CTV and 86% for those without (P<.01). For DFS, microscopic tumor outside the CTV (HR, 5.92; 95% CI, 1.89-18.54) and ypN+ (HR, 3.36; 95% CI, 1.33-8.48) were identified as independent adverse prognostic factors. The 1-year DFS was 23% versus 77% for patients with or without tumor outside the CTV (P<.01). Conclusions: Microscopic tumor outside the CTV is associated with markedly worse OS after neo-CRT. This may either stress the importance of accurate tumor delineation or reflect aggressive tumor behavior requiring new adjuvant treatment modalities.

  1. The thermal-mechanical analysis of targets for the high volume production of molybdenum-99 using a low-enriched uranium metal foil

    NASA Astrophysics Data System (ADS)

    Turner, Kyler Kriens

    Molybdenum-99 diagnostic imaging is the most commonly practiced procedure in nuclear medicine today with the majority molybdenum-99 produced with proliferation sensitive HEU. International and domestic efforts to develop non-HEU production techniques have taking the first steps toward establishing a new non-HEU molybdenum-99 based supply chain. The focus of the research presented in this work is on the analysis of a new high U-235 density LEU based molybdenum-99 production target. Converting directly to LEU using current manufacturing techniques greatly reduces the molybdenum-99 yield per target making high volume production uneconomical. The LEU based foil target analyzed in this research increases the yield per target making economic high volume production with LEU possible. The research analyzed the thermal-mechanical response of an LEU foil target during irradiation. Thermal-mechanical studies focused on deflections and stresses to assess the probability of target failure. Simpler analytical models were used to determine the proper shape of the target and to benchmark the numerical modeling software. Numerical studies using Abaqus focused on analyzing various heating and cooling conditions and assessing the effects of curvature on the target. Finally, experiments were performed to simulate low power heating and further benchmark the models. The results from all of these analyses indicate a LEU foil target could survive irradiation depending on the conditions seen during irradiation.

  2. SU-E-T-379: Concave Approximations of Target Volume Dose Metrics for Intensity- Modulated Radiotherapy Treatment Planning

    SciTech Connect

    Xie, Y; Chen, Y; Wickerhauser, M; Deasy, J

    2014-06-01

    Purpose: The widely used treatment plan metric Dx (mimimum dose to the hottest x% by volume of the target volume) is simple to interpret and use, but is computationally poorly behaved (non-convex), this impedes its use in computationally efficient intensity-modulated radiotherapy (IMRT) treatment planning algorithms. We therefore searched for surrogate metrics that are concave, computationally efficient, and accurately correlated to Dx values in IMRT treatment plans. Methods: To find concave surrogates of D95—and more generally, Dx values with variable x values—we tested equations containing one or two generalized equivalent uniform dose (gEUD) functions. Fits were obtained by varying gEUD ‘a’ parameter values, as well as the linear equation coefficients. Fitting was performed using a dataset of dose-volume histograms from 498 de-identified head and neck IMRT treatment plans. Fit characteristics were tested using a crossvalidation process. Reported root-mean-square error values were averaged over the cross-validation shuffles. Results: As expected, the two-gEUD formula provided a superior fit, compared to the single-gEUD formula. The best approximation uses two gEUD terms: 16.25 x gEUD[a=0.45] – 15.30 x gEUD[a=1.75] – 0.69. The average root-mean-square error on repeated (70/30) cross validation was 0.94 Gy. In addition, a formula was found that reasonably approximates Dx for x between 80% and 96%. Conclusion: A simple concave function using two gEUD terms was found that correlates well with PTV D95s for these head and neck treatment plans. More generally, a formula was found that represents well the Dx for x values from 80% to 96%, thus providing a computationally efficient formula for use in treatment planning optimization. The formula may need to be adjusted for other institutions with different treatment planning protocols. We conclude that the strategy of replacing Dx values with gEUD-based formulas is promising.

  3. Distance-to-Agreement Investigation of Tomotherapy's Bony Anatomy-Based Autoregistration and Planning Target Volume Contour-Based Optimization

    SciTech Connect

    Suh, Steve; Schultheiss, Timothy E.

    2013-03-01

    Purpose: To compare Tomotherapy's megavoltage computed tomography bony anatomy autoregistration with the best achievable registration, assuming no deformation and perfect knowledge of planning target volume (PTV) location. Methods and Materials: Distance-to-agreement (DTA) of the PTV was determined by applying a rigid-body shift to the PTV region of interest of the prostate from its reference position, assuming no deformations. Planning target volume region of interest of the prostate was extracted from the patient archives. The reference position was set by the 6 degrees of freedom (dof)—x, y, z, roll, pitch, and yaw—optimization results from the previous study at this institution. The DTA and the compensating parameters were calculated by the shift of the PTV from the reference 6-dof to the 4-dof—x, y, z, and roll—optimization. In this study, the effectiveness of Tomotherapy's 4-dof bony anatomy–based autoregistration was compared with the idealized 4-dof PTV contour-based optimization. Results: The maximum DTA (maxDTA) of the bony anatomy-based autoregistration was 3.2 ± 1.9 mm, with the maximum value of 8.0 mm. The maxDTA of the contour-based optimization was 1.8 ± 1.3 mm, with the maximum value of 5.7 mm. Comparison of Pearson correlation of the compensating parameters between the 2 4-dof optimization algorithms shows that there is a small but statistically significant correlation in y and z (0.236 and 0.300, respectively), whereas there is very weak correlation in x and roll (0.062 and 0.025, respectively). Conclusions: We find that there is an average improvement of approximately 1 mm in terms of maxDTA on the PTV going from 4-dof bony anatomy-based autoregistration to the 4-dof contour-based optimization. Pearson correlation analysis of the 2 4-dof optimizations suggests that uncertainties due to deformation and inadequate resolution account for much of the compensating parameters, but pitch variation also makes a statistically significant

  4. Setup Variations in Radiotherapy of Anal Cancer: Advantages of Target Volume Reduction Using Image-Guided Radiation Treatment

    SciTech Connect

    Chen Yijen; Suh, Steve; Nelson, Rebecca A.; Liu An; Pezner, Richard D.; Wong, Jeffrey Y.C.

    2012-09-01

    Purpose: To define setup variations in the radiation treatment (RT) of anal cancer and to report the advantages of image-guided RT (IGRT) in terms of reduction of target volume and treatment-related side effects. Methods and Materials: Twelve consecutive patients with anal cancer treated by combined chemoradiation by use of helical tomotherapy from March 2007 to November 2008 were selected. With patients immobilized and positioned in place, megavoltage computed tomography (MVCT) scans were performed before each treatment and were automatically registered to planning CT scans. Patients were shifted per the registration data and treated. A total of 365 MVCT scans were analyzed. The primary site received a median dose of 55 Gy. To evaluate the potential dosimetric advantage(s) of IGRT, cases were replanned according to Radiation Therapy Oncology Group 0529, with and without adding recommended setup variations from the current study. Results: Significant setup variations were observed throughout the course of RT. The standard deviations for systematic setup correction in the anterior-posterior (AP), lateral, and superior-inferior (SI) directions and roll rotation were 1.1, 3.6, and 3.2 mm, and 0.3 Degree-Sign , respectively. The average random setup variations were 3.8, 5.5, and 2.9 mm, and 0.5 Degree-Sign , respectively. Without daily IGRT, margins of 4.9, 11.1, and 8.5 mm in the AP, lateral, and SI directions would have been needed to ensure that the planning target volume (PTV) received {>=}95% of the prescribed dose. Conversely, daily IGRT required no extra margins on PTV and resulted in a significant reduction of V15 and V45 of intestine and V10 of pelvic bone marrow. Favorable toxicities were observed, except for acute hematologic toxicity. Conclusions: Daily MVCT scans before each treatment can effectively detect setup variations and thereby reduce PTV margins in the treatment of anal cancer. The use of concurrent chemotherapy and IGRT provided favorable

  5. A comparative study on the volume and localization of the internal gross target volume defined using the seroma and surgical clips based on 4DCT scan for external-beam partial breast irradiation after breast conserving surgery.

    PubMed

    Ding, Yun; Li, Jianbin; Wang, Wei; Wang, Suzhen; Wang, Jinzhi; Ma, Zhifang; Shao, Qian; Xu, Min

    2014-03-19

    To explore the volume and localization of the internal gross target volume defined using the seroma and/or surgical clips based on the four-dimensional computed tomography (4DCT) during free-breathing. Fifteen breast cancer patients after breast-conserving surgery (BCS) were recruited for EB-PBI. On the ten sets CT images, the gross target volume formed by the clips, the seroma, both the clips and seroma delineated by one radiation oncologist and defined as GTVc, GTVs and GTVc+s, respectively. The ten GTVc, GTVs and GTVc+s on the ten sets CT images produced the IGTVc, IGTVs, IGTVc+s, respectively. The IGTV volume and the distance between the center of IGTVc, IGTVs, IGTVc+s were all recorded. Conformity index (CI), degree of inclusion (DI) were calculated for IGTV/IGTV, respectively. The volume of IGTVc+s were significantly larger than the IGTVc and IGTVs (p<0.05). There was significant difference between the DIs of IGTVc vs IGTVc+s, the DIs of IGTVs vs IGTVc+s. There was significant difference among the CIs of IGTV/IGTV. The DIs and CIs of IGTV/IGTV were negatively correlated with their centroid distance (r<0, p<0.05). There were volume difference and spatial mismatch between the IGTVs delineated based on the surgical clips and seroma. The IGTV defined as the seroma and surgical clips provided the best overall representation of the 'true' moving GTV.

  6. 3D-segmentation of the 18F-choline PET signal for target volume definition in radiation therapy of the prostate.

    PubMed

    Ciernik, I Frank; Brown, Derek W; Schmid, Daniel; Hany, Thomas; Egli, Peter; Davis, J Bernard

    2007-02-01

    Volumetric assessment of PET signals becomes increasingly relevant for radiotherapy (RT) planning. Here, we investigate the utility of 18F-choline PET signals to serve as a structure for semi-automatic segmentation for forward treatment planning of prostate cancer. 18F-choline PET and CT scans of ten patients with histologically proven prostate cancer without extracapsular growth were acquired using a combined PET/CT scanner. Target volumes were manually delineated on CT images using standard software. Volumes were also obtained from 18F-choline PET images using an asymmetrical segmentation algorithm. PTVs were derived from CT 18F-choline PET based clinical target volumes (CTVs) by automatic expansion and comparative planning was performed. As a read-out for dose given to non-target structures, dose to the rectal wall was assessed. Planning target volumes (PTVs) derived from CT and 18F-choline PET yielded comparable results. Optimal matching of CT and 18F-choline PET derived volumes in the lateral and cranial-caudal directions was obtained using a background-subtracted signal thresholds of 23.0+/-2.6%. In antero-posterior direction, where adaptation compensating for rectal signal overflow was required, optimal matching was achieved with a threshold of 49.5+/-4.6%. 3D-conformal planning with CT or 18F-choline PET resulted in comparable doses to the rectal wall. Choline PET signals of the prostate provide adequate spatial information amendable to standardized asymmetrical region growing algorithms for PET-based target volume definition for external beam RT.

  7. A method to obtain correct standard uptake values in Pinnacle treatment planning system for target volume delineation.

    PubMed

    Salehzahi, Farshid; Tse, Jason; Lee, Jonathan; Selvaraj, Jothybasu

    2016-01-01

    Standardized uptake value (SUV) is an advanced tool for quantitative tumor identification and metabolic target volume delineation (TVD) in diagnostic and therapeutic settings. It is thus important to establish a quality assured process to maintain the traceability of data correctly by positron emission tomography (PET) systems. Patient administration of (18)fluoro-deoxy-glucose is increasingly delivered by automated infusion systems (AISs). Whenever AIS is used, its accuracy and traceability measurement need verification. In addition, it was observed that the unreproducible SUV displayed in PET and the treatment planning system (TPS) may cause grave concerns for radiation oncologists for TVD. This concern may complicate the correlation of TVD on PET and TPS and their clinical reporting. The SUV traceability was established from the PET system to AIS. Its accuracy was verified by cross-referencing to the reference dose calibrator traceable to a primary standard. The SUV values were converted in TPS using the in-house "clinical tool" to be identical as in PET, to allow radiation oncologists to use SUV confidently. The outcome of this study enables the clinical groups to rely on the correct SUV values displayed on the TPS and to improve the quality of care for patients in clinical procedures.

  8. Mapping patterns of nodal metastases in esophageal carcinoma: rethinking the clinical target volume for supraclavicular nodal irradiation

    PubMed Central

    Luo, Yijun; Liu, Yuhui; Wang, Xiaoli; Zhang, Bin; Yu, Jinming; Wang, Chengang; Huang, Yong

    2016-01-01

    Background To map detail distribution of metastatic supraclavicular (SCV) lymph nodes (LN) in esophageal cancer (EC) patients and determine the precise radiation therapy clinical target volume (CTV). Methods A total of 101 thoracic esophageal carcinoma patients after surgery experienced SCV LN metastasis were retrospectively examined. The SCV region is further divided into four subgroups. Using hand drawings registration, nodes were mapped to a template computed tomogram to provide a visual impression of nodal frequencies and anatomic distribution. Results In all, 158 nodes were considered to be clinical metastatic in the SCV region in the 101 patients, 74 on the left and 84 on the right. Seven of 158 (4.4%) positive LN were located in group I, 78 of 158 (49.37%) were located in group II, 72 of 158 nodes (45.6%) were located in group III, 1 of 158 (0.63%) located in group IV. Conclusions According to our results, the SCV group II and group III are considered to be the high risk regions of esophageal squamous cell carcinoma (ESCC) LN metastasis, which were defined as elective nodal irradiation (ENI) areas. PMID:28066592

  9. A method to obtain correct standard uptake values in Pinnacle treatment planning system for target volume delineation

    PubMed Central

    Salehzahi, Farshid; Tse, Jason; Lee, Jonathan; Selvaraj, Jothybasu

    2016-01-01

    Standardized uptake value (SUV) is an advanced tool for quantitative tumor identification and metabolic target volume delineation (TVD) in diagnostic and therapeutic settings. It is thus important to establish a quality assured process to maintain the traceability of data correctly by positron emission tomography (PET) systems. Patient administration of 18fluoro-deoxy-glucose is increasingly delivered by automated infusion systems (AISs). Whenever AIS is used, its accuracy and traceability measurement need verification. In addition, it was observed that the unreproducible SUV displayed in PET and the treatment planning system (TPS) may cause grave concerns for radiation oncologists for TVD. This concern may complicate the correlation of TVD on PET and TPS and their clinical reporting. The SUV traceability was established from the PET system to AIS. Its accuracy was verified by cross-referencing to the reference dose calibrator traceable to a primary standard. The SUV values were converted in TPS using the in-house “clinical tool” to be identical as in PET, to allow radiation oncologists to use SUV confidently. The outcome of this study enables the clinical groups to rely on the correct SUV values displayed on the TPS and to improve the quality of care for patients in clinical procedures. PMID:28144116

  10. Comparative analysis of the post-lumpectomy target volume versus the use of pre-lumpectomy tumor volume for early-stage breast cancer: implications for the future.

    PubMed

    Nichols, Elizabeth M; Dhople, Anil A; Mohiuddin, Majid M; Flannery, Todd W; Yu, Cedric X; Regine, William F

    2010-05-01

    Three-dimensional conformal accelerated partial breast irradiation (APBI-3D-CRT) is commonly associated with the treatment of large amounts of normal breast tissue. We hypothesized that a planning tumor volume (PTV) generation based on an expansion of the pre-lumpectomy (pre-LPC) intact tumor volume would result in smaller volumes of irradiated normal breast tissue compared with using a PTV based on the post-lumpectomy cavity (post-LPC). Use of PTVs based on the pre-LPC might also result in greater patient eligibility for APBI-3D-CRT. Forty-one early-stage breast cancers were analyzed. Preoperative imaging was used to determine a pre-LPC tumor volume. PTVs were developed in the pre- and post-LPC settings as per National Surgical Breast and Bowel Project (NSABP)-B39 guidelines. The pre- and post-LPC PTV volumes were compared and eligibility for APBI-3D-CRT determined using NSABP-B39 criteria. The post-LPC PTV exceeded the pre-LPC PTV in all cases. The median volume for the pre- and post-LPC PTVs were 93 cm(3) (range, 24-570 cm(3)) and 250 cm(3) (range, 45-879 cm(3)), respectively, p <0.001. The difference between pre- and post-LPC PTVs represented a median of 165 cc (range, 21-482 cc) or 16% (range, 3%-42%) of the whole breast volume. Three of 41 vs. 13 of 41 cases were ineligible for APBI-3D-CRT when using the pre- and post-LPC PTVs, respectively. PTVs based on pre-LPC tumor expansion are likely associated with reduced amounts of irradiated normal breast tissue compared with post-LPC PTVs, possibly leading to greater patient eligibility for APBI-3D-CRT. These findings support future investigation as to the feasibility of neoadjuvant APBI-3D-CRT.

  11. Prospective Randomized Double-Blind Pilot Study of Site-Specific Consensus Atlas Implementation for Rectal Cancer Target Volume Delineation in the Cooperative Group Setting

    SciTech Connect

    Fuller, Clifton D.; Nijkamp, Jasper; Duppen, Joop C.; Rasch, Coen R.N.; Thomas, Charles R.; Wang, Samuel J.; Okunieff, Paul; Jones, William E.; Baseman, Daniel; Patel, Shilpen; Demandante, Carlo G.N.; Harris, Anna M.; Smith, Benjamin D.; Katz, Alan W.; McGann, Camille

    2011-02-01

    Purpose: Variations in target volume delineation represent a significant hurdle in clinical trials involving conformal radiotherapy. We sought to determine the effect of a consensus guideline-based visual atlas on contouring the target volumes. Methods and Materials: A representative case was contoured (Scan 1) by 14 physician observers and a reference expert with and without target volume delineation instructions derived from a proposed rectal cancer clinical trial involving conformal radiotherapy. The gross tumor volume (GTV), and two clinical target volumes (CTVA, including the internal iliac, presacral, and perirectal nodes, and CTVB, which included the external iliac nodes) were contoured. The observers were randomly assigned to receipt (Group A) or nonreceipt (Group B) of a consensus guideline and atlas for anorectal cancers and then instructed to recontour the same case/images (Scan 2). Observer variation was analyzed volumetrically using the conformation number (CN, where CN = 1 equals total agreement). Results: Of 14 evaluable contour sets (1 expert and 7 Group A and 6 Group B observers), greater agreement was found for the GTV (mean CN, 0.75) than for the CTVs (mean CN, 0.46-0.65). Atlas exposure for Group A led to significantly increased interobserver agreement for CTVA (mean initial CN, 0.68, after atlas use, 0.76; p = .03) and increased agreement with the expert reference (initial mean CN, 0.58; after atlas use, 0.69; p = .02). For the GTV and CTVB, neither the interobserver nor the expert agreement was altered after atlas exposure. Conclusion: Consensus guideline atlas implementation resulted in a detectable difference in interobserver agreement and a greater approximation of expert volumes for the CTVA but not for the GTV or CTVB in the specified case. Visual atlas inclusion should be considered as a feature in future clinical trials incorporating conformal RT.

  12. An Effective Preoperative Three-Dimensional Radiotherapy Target Volume for Extremity Soft Tissue Sarcoma and the Effect of Margin Width on Local Control

    SciTech Connect

    Kim, Bo Kyong; Chen, Yen-Lin E.; Kirsch, David G.; Goldberg, Saveli I.; Kobayashi, Wendy; Kung, Jong Hyun; Wolfgang, John A.; Doppke, Karen

    2010-07-01

    Purpose: There is little information on the appropriate three-dimensional (3D) preoperative radiotherapy (XRT) volume for extremity soft-tissue sarcomas (STS). We retrospectively analyzed the pattern of local failure (LF) to help elucidate optimal field design. Methods and Materials: We analyzed the 56 patients who underwent computed tomography-planned XRT for Stage I to III extremity STS between June 2000 and December 2006. Clinical target volume (CTV) included the T1 post-gadolinium-defined gross tumor volume with 1- to 1.5-cm radial and 3.5-cm longitudinal margins. Planning target volume expansion was 5 to 7 mm, and {>=}95% of dose was delivered to the planning target volume. Preoperative XRT was 44 to 50.4 Gy (median, 50). Postoperative boost of 10 to 20 Gy was given to 12 patients (6 with positive and 6 with close margins). Results: Follow-up ranged from 15 to 76 months (median, 41 months). The 5-year local control, freedom from distant metastasis, disease-free survival, and overall survival were 88.5%, 80.0%, 77.5% and 82.8%, respectively. Three patients (all with positive margin) experienced local failure (LF) as first relapse (2 isolated, 1 with distant failure), and 2 additional patients (all with margin<1 mm) had late LF after distant metastasis. The LFs were within the CTV in 3 patients and within and also extending beyond the CTV in 2 patients. Conclusions: These target volume definitions appear to be appropriate for most patients. No local recurrences were observed with surgical margins {>=}1 mm, and it appears that these may be adequate for patients with extremity STS treated with preoperative radiotherapy.

  13. SU-E-T-287: Dose Verification On the Variation of Target Volume and Organ at Risk in Preradiation Chemotherapy IMRT for Nasopharyngeal Cancer

    SciTech Connect

    Zhang, X; Kong, L; Wang, J; Hu, W; Chen, Z

    2015-06-15

    Purpose: To quantify the target volume and organ at risk of nasopharyngeal carcinoma (NPC) patients with preradiation chemotherapy based on CT scanned during intensity-modulated radiotherapy (IMRT), and recalculate the dose distribution. Methods: Seven patients with NPC and preradiation chemotherapy, treated with IMRT (35 to 37 fractions) were reviewed. Repeat CT scanning was required to all of the patients during the radiotherapy, and the number of repeat CTs varies from 2 to 6. The plan CT and repeat CT were generated by different CT scanner. To ensure crespectively on the same IMPT plan. The real dose distribution was calculated by deformable registration and weighted method in Raystation (v 4.5.1). The fraction of each dose is based on radiotherapy record. The volumetric and dose differences among these images were calculated for nascIpharyngeal tumor and retro-pharyngeal lymph nodes (GTV-NX), neck lymph nodes(GTV-ND), and parotid glands. Results: The volume variation in GTV-NX from CT1 to CT2 was 1.15±3.79%, and in GTV-LN −0.23±4.93%. The volume variation in left parotid from CT1 to CT2 was −6.79±11.91%, and in right parotid −3.92±8.80%. In patient 2, the left parotid volume were decreased remarkably, as a Result, the V30 and V40 of it were increased as well. Conclusion: The target volume of patients with NPC varied lightly during IMRT. It shows that preradiation chemotherapy can control the target volume variation and perform a good dose repeatability. Also, the decreasing volume of parotid in some patient might increase the dose of it, which might course potential complications.

  14. Volumetric-modulated arc therapy for the treatment of a large planning target volume in thoracic esophageal cancer.

    PubMed

    Abbas, Ahmar S; Moseley, Douglas; Kassam, Zahra; Kim, Sun Mo; Cho, Charles

    2013-05-06

    Recently, volumetric-modulated arc therapy (VMAT) has demonstrated the ability to deliver radiation dose precisely and accurately with a shorter delivery time compared to conventional intensity-modulated fixed-field treatment (IMRT). We applied the hypothesis of VMAT technique for the treatment of thoracic esophageal carcinoma to determine superior or equivalent conformal dose coverage for a large thoracic esophageal planning target volume (PTV) with superior or equivalent sparing of organs-at-risk (OARs) doses, and reduce delivery time and monitor units (MUs), in comparison with conventional fixed-field IMRT plans. We also analyzed and compared some other important metrics of treatment planning and treatment delivery for both IMRT and VMAT techniques. These metrics include: 1) the integral dose and the volume receiving intermediate dose levels between IMRT and VMATI plans; 2) the use of 4D CT to determine the internal motion margin; and 3) evaluating the dosimetry of every plan through patient-specific QA. These factors may impact the overall treatment plan quality and outcomes from the individual planning technique used. In this study, we also examined the significance of using two arcs vs. a single-arc VMAT technique for PTV coverage, OARs doses, monitor units and delivery time. Thirteen patients, stage T2-T3 N0-N1 (TNM AJCC 7th edn.), PTV volume median 395 cc (range 281-601 cc), median age 69 years (range 53 to 85), were treated from July 2010 to June 2011 with a four-field (n = 4) or five-field (n = 9) step-and-shoot IMRT technique using a 6 MV beam to a prescribed dose of 50 Gy in 20 to 25 F. These patients were retrospectively replanned using single arc (VMATI, 91 control points) and two arcs (VMATII, 182 control points). All treatment plans of the 13 study cases were evaluated using various dose-volume metrics. These included PTV D99, PTV D95, PTV V9547.5Gy(95%), PTV mean dose, Dmax, PTV dose conformity (Van't Riet conformation number (CN)), mean lung dose

  15. Reduce in Variation and Improve Efficiency of Target Volume Delineation by a Computer-Assisted System Using a Deformable Image Registration Approach

    SciTech Connect

    Chao, K.S. Clifford . E-mail: cchao@mdanderson.org; Bhide, Shreerang FRCR; Chen, Hansen; Asper, Joshua PAC; Bush, Steven; Franklin, Gregg; Kavadi, Vivek; Liengswangwong, Vichaivood; Gordon, William; Raben, Adam; Strasser, Jon; Koprowski, Christopher; Frank, Steven; Chronowski, Gregory; Ahamad, Anesa; Malyapa, Robert; Zhang Lifei; Dong Lei

    2007-08-01

    Purpose: To determine whether a computer-assisted target volume delineation (CAT) system using a deformable image registration approach can reduce the variation of target delineation among physicians with different head and neck (HN) IMRT experiences and reduce the time spent on the contouring process. Materials and Methods: We developed a deformable image registration method for mapping contours from a template case to a patient case with a similar tumor manifestation but different body configuration. Eight radiation oncologists with varying levels of clinical experience in HN IMRT performed target delineation on two HN cases, one with base-of-tongue (BOT) cancer and another with nasopharyngeal cancer (NPC), by first contouring from scratch and then by modifying the contours deformed by the CAT system. The gross target volumes were provided. Regions of interest for comparison included the clinical target volumes (CTVs) and normal organs. The volumetric and geometric variation of these regions of interest and the time spent on contouring were analyzed. Results: We found that the variation in delineating CTVs from scratch among the physicians was significant, and that using the CAT system reduced volumetric variation and improved geometric consistency in both BOT and NPC cases. The average timesaving when using the CAT system was 26% to 29% for more experienced physicians and 38% to 47% for the less experienced ones. Conclusions: A computer-assisted target volume delineation approach, using a deformable image-registration method with template contours, was able to reduce the variation among physicians with different experiences in HN IMRT while saving contouring time.

  16. The New York Head-A precise standardized volume conductor model for EEG source localization and tES targeting.

    PubMed

    Huang, Yu; Parra, Lucas C; Haufe, Stefan

    2016-10-15

    In source localization of electroencephalograpic (EEG) signals, as well as in targeted transcranial electric current stimulation (tES), a volume conductor model is required to describe the flow of electric currents in the head. Boundary element models (BEM) can be readily computed to represent major tissue compartments, but cannot encode detailed anatomical information within compartments. Finite element models (FEM) can capture more tissue types and intricate anatomical structures, but with the higher precision also comes the need for semi-automated segmentation, and a higher computational cost. In either case, adjusting to the individual human anatomy requires costly magnetic resonance imaging (MRI), and thus head modeling is often based on the anatomy of an 'arbitrary' individual (e.g. Colin27). Additionally, existing reference models for the human head often do not include the cerebro-spinal fluid (CSF), and their field of view excludes portions of the head and neck-two factors that demonstrably affect current-flow patterns. Here we present a highly detailed FEM, which we call ICBM-NY, or "New York Head". It is based on the ICBM152 anatomical template (a non-linear average of the MRI of 152 adult human brains) defined in MNI coordinates, for which we extended the field of view to the neck and performed a detailed segmentation of six tissue types (scalp, skull, CSF, gray matter, white matter, air cavities) at 0.5mm(3) resolution. The model was solved for 231 electrode locations. To evaluate its performance, additional FEMs and BEMs were constructed for four individual subjects. Each of the four individual FEMs (regarded as the 'ground truth') is compared to its BEM counterpart, the ICBM-NY, a BEM of the ICBM anatomy, an 'individualized' BEM of the ICBM anatomy warped to the individual head surface, and FEMs of the other individuals. Performance is measured in terms of EEG source localization and tES targeting errors. Results show that the ICBM-NY outperforms

  17. SU-E-J-192: Verification of 4D-MRI Internal Target Volume Using Cine MRI

    SciTech Connect

    Lafata, K; Czito, B; Palta, M; Bashir, M; Yin, F; Cai, J

    2014-06-01

    Purpose: To investigate the accuracy of 4D-MRI in determining the Internal Target Volume (ITV) used in radiation oncology treatment planning of liver cancers. Cine MRI is used as the standard baseline in establishing the feasibility and accuracy of 4D-MRI tumor motion within the liver. Methods: IRB approval was obtained for this retrospective study. Analysis was performed on MR images from four patients receiving external beam radiation therapy for liver cancer at our institution. Eligible patients received both Cine and 4D-MRI scans before treatment. Cine images were acquired sagittally in real time at a slice bisecting the tumor, while 4D images were acquired volumetrically. Cine MR DICOM headers were manipulated such that each respiratory frame was assigned a unique slice location. This approach permitted the treatment planning system (Eclipse, Varian Medical Systems) to recognize a complete respiratory cycle as a “volume”, where the gross tumor was contoured temporally. Software was developed to calculate the union of all frame contours in the structure set, resulting in the corresponding plane of the ITV projecting through the middle of the tumor, defined as the Internal Target Area (ITA). This was repeated for 4D-MRI, at the corresponding slice location, allowing a direct comparison of ITAs obtained from each modality. Results: Four patients have been analyzed. ITAs contoured from 4D-MRI correlate with contours from Cine MRI. The mean error of 4D values relative to Cine values is 7.67 +/− 2.55 %. No single ITA contoured from 4D-MRI demonstrated more than 10.5 % error compared to its Cine MRI counterpart. Conclusion: Motion management is a significant aspect of treatment planning within dynamic environments such as the liver, where diaphragmatic and cardiac activity influence plan accuracy. This small pilot study suggests that 4D-MRI based ITA measurements agree with Cine MRI based measurements, an important step towards clinical implementation. NIH 1R21

  18. Use of Protoporphyrin Fluorescence to Determine Clinical Target Volume for Non-melanotic Skin Cancers Treated with Primary Radiotherapy

    PubMed Central

    Best, Lara; Vujovic, Olga; Jordan, Kevin; Fisher, Barbara; Carey, Deborah; Bourdeau, Deborah; Yu, Edward

    2016-01-01

    Purpose  Non-melanotic skin cancers remain the most commonly diagnosed cancers. Radiotherapy and surgery are the most common treatment options. Radiotherapy has a recurrence rate of up to 20% for basal or squamous cell cancers. One of the difficulties is to determine the extent of disease for poorly demarcated tumors. This study utilizes protoporphyrin (PpIX) fluorescence to provide information on the extent of subclinical disease for poorly demarcated tumors treated with radiotherapy. Materials and Methods  For 33 patients, PpIX photo-delineation was used to determine the clinical target volume (CTV2), which was compared to current conventional margins used to account for microscopic disease. Results  The use of PpIX photo-delineation demonstrated a significantly larger CTV of 15 mm compared to the conventional 10 mm (p = 0.03) for poorly demarcated lesions. A larger CTV was also demonstrated with PpIX photo-delineation for all basal cell carcinomas (13 mm, p = 0.03) as well as for non-nasal lesions (14 mm, p = 0.04). A trend towards an increased CTV was also noted for squamous cell carcinomas (16 mm, p = 0.19) and nasal primary sites (14 mm, p = 0.11). Nasal primary malignancies had multifocal PpIX uptake in 94% of cases. There was one case of local recurrence and one case of distant recurrence, with an average follow-up time of 22 months. Conclusions  The margins currently used to account for subclinical disease may underestimate the extent of microscopic spread for poorly demarcated tumors. Longer follow-up with larger pools of patients are necessary to determine if using PpIX photo-delineation translates into significantly improved clinical outcomes. PMID:27725923

  19. Mapping Patterns of Ipsilateral Supraclavicular Nodal Metastases in Breast Cancer: Rethinking the Clinical Target Volume for High-risk Patients

    SciTech Connect

    Jing, Hao; Wang, Shu-Lian; Li, Jing; Xue, Mei; Xiong, Zu-Kun; Jin, Jing; Wang, Wei-Hu; Song, Yong-Wen; Liu, Yue-Ping; Ren, Hua; Fang, Hui; Yu, Zi-Hao; Liu, Xin-Fan; Li, Ye-Xiong

    2015-10-01

    Purpose: To map the location of metastatic supraclavicular (SCV) lymph nodes (LNMs) in breast cancer patients with SCV node involvement and determine whether and where the radiation therapy clinical target volume (CTV) of this region could be modified in high-risk subsets. Methods and Materials: Fifty-five patients with metastatic SCV LNMs were eligible for geographic mapping and atlas coverage analysis. All LNMs and their epicenters were registered proportionally by referencing the surrounding landmarks onto simulation computed tomography images of a standard patient. CTVs based on selected SCV atlases, including the one by the Radiation Therapy Oncology Group (RTOG) were contoured. A modified SCV CTV was tried and shown to have better involved-node coverage and thus theoretically improved prophylaxis in this setting. Results: A total of 50 (91%) and 45 (81.8%) patients had LNMs in the medial and lateral SCV subregions, respectively. Also, 36 patients (65.5%) had LNMs located at the junction of the jugular-subclavian veins. All nodes were covered in only 25.5% to 41.8% of patients by different atlases. The RTOG atlas covered all nodes in 25.5% of patients. Stratified by the nodes in all the patients as a whole, 49.2% to 81.3% were covered, and the RTOG atlas covered 62.6%. The lateral and posterior borders were the most overlooked locations. Modification by extending the borders to natural anatomic barriers allowed the new CTV to cover all the nodes in 81.8% of patients and encompass 96.1% of all the nodes. Conclusions: According to the distribution of SCV LNMs, the extent of existing atlases might not be adequate for potential metastatic sites in certain groups of patients. The extension of the lateral and posterior CTV borders in high-risk or recurrent patients might be a reasonable approach for increasing coverage. However, additional data in more homogeneous populations with localized disease are needed before routine application.

  20. Comparison of Efficacy of Regional and Extensive Clinical Target Volumes in Postoperative Radiotherapy for Esophageal Squamous Cell Carcinoma

    SciTech Connect

    Qiao Xueying; Wang Wei; Zhou Zhiguo; Gao Xianshu; Chang, Joe Y.

    2008-02-01

    Purpose: To compare and analyze the effect of different clinical target volumes (CTVs) on survival rate after postoperative radiotherapy (RT) for esophageal squamous cell carcinoma (SCC). Methods and Materials: We studied 102 patients who underwent postoperative RT after radical resection for esophageal SCC (T3/4 or N1). The radiation dose was {>=}50 Gy. In the extensive portal group (E group, 43 patients), the CTV encompassed the bilateral supraclavicular region, all mediastinal lymph nodes, the anastomosis site, and the left gastric and pericardial lymphatic. In the regional portal group (R group, 59 patients), the CTV was confined to tumor bed and the lymph nodes in the immediate region of the primary lesion. The 1-, 3-, and 5-year survival rates were compared between the groups, and multivariate/univariate analysis for factors predicting survival was studied. Results: For the entire group, the 1-, 3- and 5-year survival rates were 76.3%, 50.5%, and 42.9%, respectively (median survival, 30 months). The 1-, 3-, and 5-year survival rates were 76.5%, 52.1%, and 41.3%, respectively, in the E group and 76.2%, 49.2%, and 44.6%, respectively, in the R group (not significant). According to the multivariate analysis, N stage, number of lymph nodes with metastatic disease, and tumor length were the independent prognostic factors for survival. Conclusions: Using a regional portal in postoperative RT for esophageal SCC is not associated with compromised survival compared with extensive portal RT and therefore should be considered. N stage, number of affected lymph nodes, and tumor length predict poor survival.

  1. 45th Annual Targets, UAVs and Range Operations Symposium and Exhibition - Tools and Technologies for the Warfighter. Volume 2. Wednesday

    DTIC Science & Technology

    2007-10-31

    Department, Pt . Mugu, CA DOT&E Targets Overview, Mr. Joshua Messner, DOT&E Target Resources, OSD JSF Range and Airspace Requirements, Major “Digger” Davis...Target Operational & Engineering Support Thomas Dowd, Dir, Threat Target Systems, Pt Mugu 11:05AM JSF: Targets & Ranges Test & Training Requirements...Col Russell Handy, Commander, 33d Fighter Wing 11:50AM Improvements & Upgrades at the Sea Range Karen Draper, Sea Range Test Mgmt Br, Pt Mugu 12

  2. Impact of 18-fluorodeoxyglucose positron emission tomography on computed tomography defined target volumes in radiation treatment planning of esophageal cancer: reduction in geographic misses with equal inter-observer variability: PET/CT improves esophageal target definition.

    PubMed

    Schreurs, L M A; Busz, D M; Paardekooper, G M R M; Beukema, J C; Jager, P L; Van der Jagt, E J; van Dam, G M; Groen, H; Plukker, J Th M; Langendijk, J A

    2010-08-01

    Target volume definition in modern radiotherapy is based on planning computed tomography (CT). So far, 18-fluorodeoxyglucose positron emission tomography (FDG-PET) has not been included in planning modality in volume definition of esophageal cancer. This study evaluates fusion of FDG-PET and CT in patients with esophageal cancer in terms of geographic misses and inter-observer variability in volume definition. In 28 esophageal cancer patients, gross, clinical and planning tumor volumes (GTV; CTV; PTV) were defined on planning CT by three radiation oncologists. After software-based emission tomography and computed tomography (PET/CT) fusion, tumor delineations were redefined by the same radiation-oncologists. Concordance indexes (CCI's) for CT and PET/CT based GTV, CTV and PTV were calculated for each pair of observers. Incorporation of PET/CT modified tumor delineation in 17/28 subjects (61%) in cranial and/or caudal direction. Mean concordance indexes for CT-based CTV and PTV were 72 (55-86)% and 77 (61-88)%, respectively, vs. 72 (47-99)% and 76 (54-87)% for PET/CT-based CTV and PTV. Paired analyses showed no significant difference in CCI between CT and PET/CT. Combining FDG-PET and CT may improve target volume definition with less geographic misses, but without significant effects on inter-observer variability in esophageal cancer.

  3. A comparative study of target volumes based on 18F-FDG PET-CT and ten phases of 4DCT for primary thoracic squamous esophageal cancer

    PubMed Central

    Guo, Yanluan; Li, Jianbin; Zhang, Peng; Zhang, Yingjie

    2017-01-01

    Purpose To investigate the correlations in target volumes based on 18F-FDG PET/CT and four-dimensional CT (4DCT) to detect the feasibility of implementing PET in determining gross target volumes (GTV) for tumor motion for primary thoracic esophageal cancer (EC). Methods Thirty-three patients with EC sequentially underwent contrast-enhanced 3DCT, 4DCT, and 18F-FDG PET-CT thoracic simulation. The internal gross target volume (IGTV)10 was obtained by combining the GTV from ten phases of 4DCT. The GTVs based on PET/CT images were defined by setting of different standardized uptake value thresholds and visual contouring. The difference in volume ratio, conformity index (CI), and degree of inclusion (DI) between IGTV10 and GTVPET was compared. Results The images from 20 patients were suitable for further analysis. The optimal volume ratio of 0.95±0.32, 1.06±0.50, 1.07±0.49 was at standardized uptake value (SUV)2.5, SUV20%, or manual contouring. The mean CIs were from 0.33 to 0.54. The best CIs were at SUV2.0 (0.51±0.11), SUV2.5 (0.53±0.13), SUV20% (0.53±0.12), and manual contouring (0.54±0.14). The mean DIs of GTVPET in IGTV10 were from 0.60 to 0.90, and the mean DIs of IGTV10 in GTVPET ranged from 0.35 to 0.78. A negative correlation was found between the mean CI and different SUV (P=0.000). Conclusion None of the PET-based contours had both close spatial and volumetric approximation to the 4DCT IGTV10. Further evaluation and optimization of PET as a tool for target identification are required. PMID:28123302

  4. Quantitative evaluation of cone-beam computed tomography in target volume definition for offline image-guided radiation therapy of prostate cancer.

    PubMed

    Wang, Weihu; Wu, Qiuwen; Yan, Di

    2010-01-01

    To quantitatively evaluate cone-beam CT (CBCT) in target volume definition in an offline image guidance environment. Fifteen patients each with five helical CTs (HCT) and eight CBCTs were included. A single physician manually delineated prostate and seminal vesicles (SVs) on each CT. The clinical target volume (CTV) was prostate for low risk group (G1), plus SVs for intermediate risk group (G2). The internal target volumes (ITVs) on CBCT (ITV(CBCT)) were constructed and compared with ITV(HCT). The following comparisons were performed: CTV and ITV in HCT and CBCT; similarity of ITVs using overlap index (OI); surface differences between ITVs; quality assurance of ITV(CBCT) using CTV from weekly CBCT; and dosimetric evaluations of ITV(HCT) coverage on plans from ITV(CBCT). There was no statistical significant difference of CTV or ITV. The ITV OIs were 91%/88% for G1/G2 patients. They improved significantly with 1-2mm margins. Therefore, the ITVs were mostly within 2mm. The CTVs from weekly CBCT had >95% overlap with ITV(CBCT). The ITV dose differences (D(95), and D(mean)) were <0.3%. It is feasible to use CBCT for target definition in offline image guidance, thereby eliminating the separate helical CT scan process. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

  5. Radioimmunoguided-intraoperative radiation therapy in colorectal carcinoma: a new technique to precisely define the clinical target volume.

    PubMed

    Nag, S; Martinez-Monge, R; Nieroda, C; Martin, E

    1999-04-01

    The clinical target volume (CTV) to be irradiated by intraoperative radiation therapy (IORT) after resection is generally based on the surgeon's estimation of close margins. We have developed a new technique, radioimmunoguided-intraoperative radiation therapy (RIG-IORT), that uses an intraoperative hand-held gamma-detecting probe to define areas of residual microscopic disease containing radiolabeled monoclonal antibodies to tumor associated antigen, to more precisely delineate the CTV for IORT. Patients were injected i.v. with 2 mCi 125I- radiolabeled CC49 antibody approximately 3 weeks before surgery. They then underwent radioimmunoguided surgery (RIGS) with maximal resection of tumor. A hand-held gamma-detecting probe (Neoprobe 1000) was used intraoperatively to detect and resect areas of high radioactivity, representing tumor. Areas with persistently high probe counts after resection were the areas of occult residual disease, and represented the CTV to be irradiated. The IORT was given with either 6-9 MeV electron beam from a dedicated linear accelerator, or with high-dose-rate brachytherapy from a remote afterloader. If all RIGS-positive tissue had been resected, or if widely disseminated disease remained, the patient was not considered for IORT. This technique was used in 31 patients with colorectal adenocarcinoma recurrent into the pelvis (n = 23) or paraortic nodes (n = 8). The CTV for IORT was delineated by increased RIGS count in 13 of 19 patients (68%) with microscopic residual, and in 11 of 12 patients (92%) with gross residual. In the other 7 patients, the tumor area did not accumulate the radiolabeled antibody; therefore, these tumor beds were irradiated based on the surgeon's estimation of close margins. Hence, overall, the RIG-IORT technique was used to define the tumor bed for IORT in 24 of 31 patients (77%). This technical report focuses on the development of the RIG-IORT technique and does not address the outcome results of the treated patients

  6. Monte-Carlo model development for evaluation of current clinical target volume definition for heterogeneous and hypoxic glioblastoma

    NASA Astrophysics Data System (ADS)

    Moghaddasi, L.; Bezak, E.; Harriss-Phillips, W.

    2016-05-01

    Clinical target volume (CTV) determination may be complex and subjective. In this work a microscopic-scale tumour model was developed to evaluate current CTV practices in glioblastoma multiforme (GBM) external radiotherapy. Previously, a Geant4 cell-based dosimetry model was developed to calculate the dose deposited in individual GBM cells. Microscopic extension probability (MEP) models were then developed using Matlab-2012a. The results of the cell-based dosimetry model and MEP models were combined to calculate survival fractions (SF) for CTV margins of 2.0 and 2.5 cm. In the current work, oxygenation and heterogeneous radiosensitivity profiles were incorporated into the GBM model. The genetic heterogeneity was modelled using a range of α/β values (linear-quadratic model parameters) associated with different GBM cell lines. These values were distributed among the cells randomly, taken from a Gaussian-weighted sample of α/β values. Cellular oxygen pressure was distributed randomly taken from a sample weighted to profiles obtained from literature. Three types of GBM models were analysed: homogeneous-normoxic, heterogeneous-normoxic, and heterogeneous-hypoxic. The SF in different regions of the tumour model and the effect of the CTV margin extension from 2.0-2.5 cm on SFs were investigated for three MEP models. The SF within the beam was increased by up to three and two orders of magnitude following incorporation of heterogeneous radiosensitivities and hypoxia, respectively, in the GBM model. However, the total SF was shown to be overdominated by the presence of tumour cells in the penumbra region and to a lesser extent by genetic heterogeneity and hypoxia. CTV extension by 0.5 cm reduced the SF by a maximum of 78.6  ±  3.3%, 78.5  ±  3.3%, and 77.7  ±  3.1% for homogeneous and heterogeneous-normoxic, and heterogeneous hypoxic GBMs, respectively. Monte-Carlo model was developed to quantitatively evaluate SF for genetically

  7. Monte-Carlo model development for evaluation of current clinical target volume definition for heterogeneous and hypoxic glioblastoma.

    PubMed

    Moghaddasi, L; Bezak, E; Harriss-Phillips, W

    2016-05-07

    Clinical target volume (CTV) determination may be complex and subjective. In this work a microscopic-scale tumour model was developed to evaluate current CTV practices in glioblastoma multiforme (GBM) external radiotherapy. Previously, a Geant4 cell-based dosimetry model was developed to calculate the dose deposited in individual GBM cells. Microscopic extension probability (MEP) models were then developed using Matlab-2012a. The results of the cell-based dosimetry model and MEP models were combined to calculate survival fractions (SF) for CTV margins of 2.0 and 2.5 cm. In the current work, oxygenation and heterogeneous radiosensitivity profiles were incorporated into the GBM model. The genetic heterogeneity was modelled using a range of α/β values (linear-quadratic model parameters) associated with different GBM cell lines. These values were distributed among the cells randomly, taken from a Gaussian-weighted sample of α/β values. Cellular oxygen pressure was distributed randomly taken from a sample weighted to profiles obtained from literature. Three types of GBM models were analysed: homogeneous-normoxic, heterogeneous-normoxic, and heterogeneous-hypoxic. The SF in different regions of the tumour model and the effect of the CTV margin extension from 2.0-2.5 cm on SFs were investigated for three MEP models. The SF within the beam was increased by up to three and two orders of magnitude following incorporation of heterogeneous radiosensitivities and hypoxia, respectively, in the GBM model. However, the total SF was shown to be overdominated by the presence of tumour cells in the penumbra region and to a lesser extent by genetic heterogeneity and hypoxia. CTV extension by 0.5 cm reduced the SF by a maximum of 78.6  ±  3.3%, 78.5  ±  3.3%, and 77.7  ±  3.1% for homogeneous and heterogeneous-normoxic, and heterogeneous hypoxic GBMs, respectively. Monte-Carlo model was developed to quantitatively evaluate SF for genetically

  8. Doses to radiation sensitive organs and structures located outside the radiotherapeutic target volume for four treatment situations

    SciTech Connect

    Foo, M.L.; McCullough, E.C.; Foote, R.L.; Pisansky, T.M.; Shaw, E.G. )

    1993-09-20

    This study documents dosage to radiation sensitive organs/structures located outside the radiotherapeutic target volume for four treatment situations: (a) head and neck, (b) brain (pituitary and temporal lobe), (c) breast and (d) pelvis. Clinically relevant treatment fields were simulated on a tissue-equivalent anthropomorphic phantom and subsequently irradiated with Cobalt-60 gamma rays, 6- and 18-MV x-ray beams. Thermoluminescent dosimeters and diodes were used to measure absorbed dose. The head and neck treatment resulted in significant doses of radiation to the lens and thyroid gland. The total treatment lens dose (300-400 cGy) could be cataractogenic while measured thyroid doses (1000-8000 cGy) have the potential of causing chemical hypothyroidism, thyroid neoplasms, Graves' disease and hyperparathyroidism. Total treatment retinal (400-700 cGy) and pituitary (460-1000 cGy) doses are below that considered capable of producing chronic disease. The pituitary treatment studied consisted of various size parallel opposed lateral and vertex fields (4 x 4 through 8 x 8 cm). The lens dose (40-200 cGy) with all field sizes is below those of clinical concern. Parotid doses (130-1200 cGy) and thyroid doses (350-600 cGy) are in a range where temporary xerostomia (parotid) and thyroid neoplasia development are a reasonable possibility. The retinal dose (4000 cGy) from the largest field size (8 x 8 cm[sup 2]) is in the range where retinopathy has been reported. The left temporal lobe treatment also used parallel opposed lateral and vertex fields (7 x 7 and 10 x 10 cm). Doses to the pituitary gland (5200-6200 cGy), both parotids (200-6900 cGy), left lens (200-300 cGy), and left retina (1700-4500 cGy) are capable of causing significant future clinical problems. Right-sided structures received insignificant doses. Secondary malignancies could result from the measured total treatment thyroid doses (670-980 cGy). 82 refs., 7 figs., 5 tabs.

  9. Impact of 18FDG-PET/CT on biological target volume (BTV) definition for treatment planning for non-small cell lung cancer patients

    NASA Astrophysics Data System (ADS)

    Devic, Slobodan; Tomic, Nada; Faria, Sergio; Dean, Geoffrey; Lisbona, Robert; Parker, William; Kaufman, Chris; Podgorsak, Ervin B.

    2007-02-01

    This work represents our effort to test feasibility of FDG-based PET/CT on target volume delineation in radiotherapy treatment planning of NSCLC patients. Different methods have been developed to enable more precise target outlining using PET: Qualitative Visual Method, CTV=2.5 SUV units, linear SUV threshold function method, and CTV=40% Iso of Maximum Uptake Value. We are proposing reconstruction of three biological target volumes: necrotic BTV (same as PTV created by radiation oncologist using CT data), proliferating BTV (based on PET signal to background ratio 1:3) and hypoxic BTV (based on PET signal to background ratio of 1:19). Two IMRT plans were created and compared to the conventional treatment plan: "conservative" IMRT plan delivers 52.5 Gy to the necrotic BTV and 65 Gy to the hypoxic BTV; "radical" IMRT plan delivers 30 Gy to necrotic BTV, 52.5 Gy to proliferating BTV and 65 Gy to hypoxic BTV. Use of BTVs in IMRT plans is attractive because it increases dose to targets considered to need higher doses. It reduces considerably dose to heart and spinal cord, organs considered to limit dose escalation approaches in NSCLC treatment. "Conservative" IMRT approach can be understood as a PET/CT-based concomitant boost to the tumor expressing the highest FDG uptake. "Radical" plan implies deviation from the traditional uniform dose target coverage approach, with the intention of achieving better surrounding tissue sparing and ultimately allowing for dose escalation protocols relying on biologically based treatment planning.

  10. Comparative evaluation of target volumes defined by deformable and rigid registration of diagnostic PET/CT to planning CT in primary esophageal cancer.

    PubMed

    Guo, Yanluan; Li, Jianbin; Zhang, Peng; Shao, Qian; Xu, Min; Li, Yankang

    2017-01-01

    To evaluate the geometrical differences of target volumes propagated by deformable image registration (DIR) and rigid image registration (RIR) to assist target volume delineation between diagnostic Positron emission tomography/computed tomography (PET/CT) and planning CT for primary esophageal cancer (EC). Twenty-five patients with EC sequentially underwent a diagnostic F-fluorodeoxyglucose (F-FDG) PET/CT scan and planning CT simulation. Only 19 patients with maximum standardized uptake value (SUVmax) ≥ 2.0 of the primary volume were available. Gross tumor volumes (GTVs) were delineated using CT and PET display settings. The PET/CT images were then registered with planning CT using MIM software. Subsequently, the PET and CT contours were propagated by RIR and DIR to planning CT. The properties of these volumes were compared. When GTVCT delineated on CT of PET/CT after both RIR and DIR was compared with GTV contoured on planning CT, significant improvements using DIR were observed in the volume, displacements of the center of mass (COM) in the 3-dimensional (3D) direction, and Dice similarity coefficient (DSC) (P = 0.003; 0.006; 0.014). Although similar improvements were not observed for the same comparison using DIR for propagated PET contours from diagnostic PET/CT to planning CT (P > 0.05), for DSC and displacements of COM in the 3D direction of PET contours, the DIR resulted in the improved volume of a large percentage of patients (73.7%; 68.45%; 63.2%) compared with RIR. For diagnostic CT-based contours or PET contours at SUV2.5 propagated by DIR with planning CT, the DSC and displacements of COM in 3D directions in the distal segment were significantly improved compared to the upper and middle segments (P > 0.05). We observed a trend that deformable registration might improve the overlap for gross target volumes from diagnostic PET/CT to planning CT. The distal EC might benefit more from DIR.

  11. Comparative evaluation of target volumes defined by deformable and rigid registration of diagnostic PET/CT to planning CT in primary esophageal cancer

    PubMed Central

    Guo, Yanluan; Li, Jianbin; Zhang, Peng; Shao, Qian; Xu, Min; Li, Yankang

    2017-01-01

    Abstract Background: To evaluate the geometrical differences of target volumes propagated by deformable image registration (DIR) and rigid image registration (RIR) to assist target volume delineation between diagnostic Positron emission tomography/computed tomography (PET/CT) and planning CT for primary esophageal cancer (EC). Methods: Twenty-five patients with EC sequentially underwent a diagnostic 18F-fluorodeoxyglucose (18F-FDG) PET/CT scan and planning CT simulation. Only 19 patients with maximum standardized uptake value (SUVmax) ≥ 2.0 of the primary volume were available. Gross tumor volumes (GTVs) were delineated using CT and PET display settings. The PET/CT images were then registered with planning CT using MIM software. Subsequently, the PET and CT contours were propagated by RIR and DIR to planning CT. The properties of these volumes were compared. Results: When GTVCT delineated on CT of PET/CT after both RIR and DIR was compared with GTV contoured on planning CT, significant improvements using DIR were observed in the volume, displacements of the center of mass (COM) in the 3-dimensional (3D) direction, and Dice similarity coefficient (DSC) (P = 0.003; 0.006; 0.014). Although similar improvements were not observed for the same comparison using DIR for propagated PET contours from diagnostic PET/CT to planning CT (P > 0.05), for DSC and displacements of COM in the 3D direction of PET contours, the DIR resulted in the improved volume of a large percentage of patients (73.7%; 68.45%; 63.2%) compared with RIR. For diagnostic CT-based contours or PET contours at SUV2.5 propagated by DIR with planning CT, the DSC and displacements of COM in 3D directions in the distal segment were significantly improved compared to the upper and middle segments (P > 0.05). Conclusion: We observed a trend that deformable registration might improve the overlap for gross target volumes from diagnostic PET/CT to planning CT. The distal EC might benefit more from DIR

  12. Will weight loss cause significant dosimetric changes of target volumes and organs at risk in nasopharyngeal carcinoma treated with intensity-modulated radiation therapy?

    SciTech Connect

    Chen, Chuanben; Fei, Zhaodong; Chen, Lisha; Bai, Penggang; Lin, Xiang; Pan, Jianji

    2014-04-01

    This study aimed to quantify dosimetric effects of weight loss for nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT). Overall, 25 patients with NPC treated with IMRT were enrolled. We simulated weight loss during IMRT on the computer. Weight loss model was based on the planning computed tomography (CT) images. The original external contour of head and neck was labeled plan 0, and its volume was regarded as pretreatment normal weight. We shrank the external contour with different margins (2, 3, and 5 mm) and generated new external contours of head and neck. The volumes of reconstructed external contours were regarded as weight during radiotherapy. After recontouring outlines, the initial treatment plan was mapped to the redefined CT scans with the same beam configurations, yielding new plans. The computer model represented a theoretical proportional weight loss of 3.4% to 13.7% during the course of IMRT. The dose delivered to the planning target volume (PTV) of primary gross tumor volume and clinical target volume significantly increased by 1.9% to 2.9% and 1.8% to 2.9% because of weight loss, respectively. The dose to the PTV of gross tumor volume of lymph nodes fluctuated from −2.0% to 1.0%. The dose to the brain stem and the spinal cord was increased (p < 0.001), whereas the dose to the parotid gland was decreased (p < 0.001). Weight loss may lead to significant dosimetric change during IMRT. Repeated scanning and replanning for patients with NPC with an obvious weight loss may be necessary.

  13. Comparative evaluation of respiratory-gated and ungated FDG-PET for target volume definition in radiotherapy treatment planning for pancreatic cancer.

    PubMed

    Kishi, Takahiro; Matsuo, Yukinori; Nakamura, Akira; Nakamoto, Yuji; Itasaka, Satoshi; Mizowaki, Takashi; Togashi, Kaori; Hiraoka, Masahiro

    2016-08-01

    The purpose of this study was to evaluate the usefulness of respiratory-gated positron emission tomography (4D-PET) in pancreatic cancer radiotherapy treatment planning (RTTP). Fourteen patients with 18F-fluorodeoxyglucose (FDG)-avid pancreatic tumours were evaluated between December 2013 and March 2015. Two sets of volumes were contoured for the pancreatic tumour of each patient. The biological target volume in three-dimensional RTTP (BTV3D) was contoured using conventional respiratory un-gated PET. The BTV3D was then expanded using population-based margins to generate a series of internal target volume 3D (ITV3D) values. The ITV 4D (ITV4D) was contoured using 4D-PET. Each of the five phases of 4D-PET was used for 4D contouring, and the ITV4D was constructed by summing the volumes defined on the five individual 4D-PET images. The relative volumes and normalized volumetric overlap were computed between ITV3D and ITV4D. On average, the FDG-avid tumour volumes were 1.6 (range: 0.8-2.3) fold greater in the ITV4D than in the BTV3D. On average, the ITV3D values were 2.0 (range: 1.1-3.4) fold larger than the corresponding ITV4D values. The ITV generated from 4D-PET can be used to improve the accuracy or reduce normal tissue irradiation compared with conventional un-gated PET-based ITV. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. TU-A-12A-06: Intra-Observer Variability in Delineation of Target Volumes in Breast Radiotherapy and Its Effect On Accuracy of Deformation Measurements

    SciTech Connect

    Juneja, P; Harris, E; Bonora, M; Evans, P

    2014-06-15

    Purpose: In breast radiotherapy, the target volume may change during treatment and need adaptation of the treatment plan. This is possible for both tumour bed (TB) and whole breast (WB) target volumes. Delineation of the target (to detect changes) is also subject to uncertainty due to intra- and inter-observer variability. This work measured the uncertainty, due to intraobserver variability, in the quantification of tissue deformation. Methods: Datasets consisting of paired prone and supine CT scans of three patients were used. Significant deformation in target volumes is expected between prone and supine patient positions. The selected cases had 1) no seroma, 2) some seroma, and 3) large seroma. The TB and WB were outlined on each dataset three times by one clinician. Delineation variability was defined as the standard deviations of the distances between observer outlines. For each target volume and each case, tissue deformation between prone and supine delineations was quantified using the Dice similarity coefficient (DSC) and the average surface distance (ASD). The uncertainty in the tissue deformation (due to delineation variability) was quantified by measuring the ranges of DSC and ASD using all combinations of pairs of outlines (9 pairs). Results: For the TB, the range of delineation variability was 0.44-1.16 mm. The deformation, DSC and ASD, (and uncertainty in measurement) of the TB between prone and supine position of the cases were: 1) 0.21 (0.17-0.28) and 12.4 mm (11.8-13 mm); 2) 0.54 (0.51-0.57) and 3.3 mm (3.1-3.5 mm); 3) 0.62 (0.61-0.64) and 4.9 mm (4.6-5.2 mm). WB deformation measurements were subject to less uncertainty due to delineation variability than TB deformation measurements. Conclusion: For the first time, the uncertainty, due to observer variability, in the measurement of the deformation of breast target volumes was investigated. Deformations in these ranges would be difficult to detect. This work was supported in part by Cancer Research

  15. Determining optimal clinical target volume margins in head-and-neck cancer based on microscopic extracapsular extension of metastatic neck nodes

    SciTech Connect

    Apisarnthanarax, Smith; Elliott, Danielle D.; El-Naggar, Adel K.; Asper, Joshua A. P.A.; Blanco, Angel; Ang, K. Kian; Garden, Adam S.; Morrison, William H.; Rosenthal, David; Weber, Randal S.; Chao, K.S. Clifford . E-mail: cchao@mdanderson.org

    2006-03-01

    Purpose: To determine the optimal clinical target volume margins around the gross nodal tumor volume in head-and-neck cancer by assessing microscopic tumor extension beyond cervical lymph node capsules. Methods and Materials: Histologic sections of 96 dissected cervical lymph nodes with extracapsular extension (ECE) from 48 patients with head-and-neck squamous cell carcinoma were examined. The maximum linear distance from the external capsule border to the farthest extent of the tumor or tumoral reaction was measured. The trends of ECE as a function of the distance from the capsule and lymph node size were analyzed. Results: The median diameter of all lymph nodes was 11.0 mm (range: 3.0-30.0 mm). The mean and median ECE extent was 2.2 mm and 1.6 mm, respectively (range: 0.4-9.0 mm). The ECE was <5 mm from the capsule in 96% of the nodes. As the distance from the capsule increased, the probability of tumor extension declined. No significant difference between the extent of ECE and lymph node size was observed. Conclusion: For N1 nodes that are at high risk for ECE but not grossly infiltrating musculature, 1 cm clinical target volume margins around the nodal gross tumor volume are recommended to cover microscopic nodal extension in head-and-neck cancer.

  16. The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy

    SciTech Connect

    Clements, N.; Kron, T.; Roxby, P.; Franich, R.; Dunn, L.; Aarons, Y.; Chesson, B.; Siva, S.; Duplan, D.; Ball, D.

    2013-02-15

    Purpose: Stereotactic lung radiotherapy is complicated by tumor motion from patient respiration. Four-dimensional CT (4DCT) imaging is a motion compensation method used in treatment planning to generate a maximum intensity projection (MIP) internal target volume (ITV). Image guided radiotherapy during treatment may involve acquiring a volumetric cone-beam CT (CBCT) image and visually aligning the tumor to the planning 4DCT MIP ITV contour. Moving targets imaged with CBCT can appear blurred and currently there are no studies reporting on the effect that irregular breathing patterns have on CBCT volumes and their alignment to 4DCT MIP ITV contours. The objective of this work was therefore to image a phantom moving with irregular breathing patterns to determine whether any configurations resulted in errors in volume contouring or alignment. Methods: A Perspex thorax phantom was used to simulate a patient. Three wooden 'lung' inserts with embedded Perspex 'lesions' were moved up to 4 cm with computer-generated motion patterns, and up to 1 cm with patient-specific breathing patterns. The phantom was imaged on 4DCT and CBCT with the same acquisition settings used for stereotactic lung patients in the clinic and the volumes on all phantom images were contoured. This project assessed the volumes for qualitative and quantitative changes including volume, length of the volume, and errors in alignment between CBCT volumes and 4DCT MIP ITV contours. Results: When motion was introduced 4DCT and CBCT volumes were reduced by up to 20% and 30% and shortened by up to 7 and 11 mm, respectively, indicating that volume was being under-represented at the extremes of motion. Banding artifacts were present in 4DCT MIP images, while CBCT volumes were largely reduced in contrast. When variable amplitudes from patient traces were used and CBCT ITVs were compared to 4DCT MIP ITVs there was a distinct trend in reduced ITV with increasing amplitude that was not seen when compared to true ITVs

  17. The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy.

    PubMed

    Clements, N; Kron, T; Franich, R; Dunn, L; Roxby, P; Aarons, Y; Chesson, B; Siva, S; Duplan, D; Ball, D

    2013-02-01

    Stereotactic lung radiotherapy is complicated by tumor motion from patient respiration. Four-dimensional CT (4DCT) imaging is a motion compensation method used in treatment planning to generate a maximum intensity projection (MIP) internal target volume (ITV). Image guided radiotherapy during treatment may involve acquiring a volumetric cone-beam CT (CBCT) image and visually aligning the tumor to the planning 4DCT MIP ITV contour. Moving targets imaged with CBCT can appear blurred and currently there are no studies reporting on the effect that irregular breathing patterns have on CBCT volumes and their alignment to 4DCT MIP ITV contours. The objective of this work was therefore to image a phantom moving with irregular breathing patterns to determine whether any configurations resulted in errors in volume contouring or alignment. A Perspex thorax phantom was used to simulate a patient. Three wooden "lung" inserts with embedded Perspex "lesions" were moved up to 4 cm with computer-generated motion patterns, and up to 1 cm with patient-specific breathing patterns. The phantom was imaged on 4DCT and CBCT with the same acquisition settings used for stereotactic lung patients in the clinic and the volumes on all phantom images were contoured. This project assessed the volumes for qualitative and quantitative changes including volume, length of the volume, and errors in alignment between CBCT volumes and 4DCT MIP ITV contours. When motion was introduced 4DCT and CBCT volumes were reduced by up to 20% and 30% and shortened by up to 7 and 11 mm, respectively, indicating that volume was being under-represented at the extremes of motion. Banding artifacts were present in 4DCT MIP images, while CBCT volumes were largely reduced in contrast. When variable amplitudes from patient traces were used and CBCT ITVs were compared to 4DCT MIP ITVs there was a distinct trend in reduced ITV with increasing amplitude that was not seen when compared to true ITVs. Breathing patterns with a

  18. What's new in target volume definition for radiologists in ICRU Report 71? How can the ICRU volume definitions be integrated in clinical practice?

    PubMed

    Berthelsen, Anne Kiil; Dobbs, Jane; Kjellén, Elisabeth; Landberg, Torsten; Möller, Torgil R; Nilsson, Per; Specht, Lena; Wambersie, André

    2007-06-11

    The optimal definition of the size, shape and location of gross tumour volume is one of the most important steps in the planning of radiation therapy, and necessitates a proper understanding of the procedure from both the oncologic radiologist and the radiation oncologist. This overview reports on the different terms and concepts that have been recommended in the ICRU Reports for this purpose; the latest Report 71 focuses on both previously given recommendations, and especially on electron beam therapy. This paper also highlights some of the problems that are encountered in the use of the International Commission on Radiation Units and Measurements (ICRU) recommendations in clinical practice, and at the interface between the radiation oncologist and the diagnostic oncologist.

  19. Evaluation of a volume targeted NIV device: bench evaluation of the Breathe Technologies non-invasive open ventilation system (NIOV™).

    PubMed

    Blakeman, Thomas; Branson, Richard

    2014-09-01

    Early ambulation in the ventilated patient is gaining wider acceptance. We evaluated a new portable (1 lb), gas powered, volume ventilator designed for NIV via a proprietary nasal pillows interface (Breathe Technologies, CA). We developed a model to approximate a patient's nose, upper airway and trachea. The model was connected to a test lung (ASL5000, Ingmar Medical, Pittsburgh, PA) via 22 mm ID corrugated tubing. The nasal pillows were adjusted in the nares using a lanyard. The ASL was set to represent a normal patient, a COPD patient, and a patient with interstitial lung disease (ILD). The Breathe ventilator was set at delivered volumes of 100 mL, 150 mL, 200 mL, and 250 mL. Baseline data was also collected without the appliance connected. Delivered volume, inspired oxygen concentration (FIO2), inspiratory flow (V), and peak inspiratory pressure (PIP) were recorded for each breath. Data for 10 breaths were used to calculate the mean at each condition (± SD). The Breathe volume ventilator delivered an augmented simulated patient tidal volume of 362 to 823 mL, augmenting the simulated patient's spontaneous volume by up to 459 mL, depending on ventilator settings and ASL lung conditions. Delivered FIO2 ranged from 0.36 to 0.45 and was also dependent on ventilator settings and ASL lung conditions. The PIP, delivered tidal volumes, and measured FIO2 support the hypothesis that this system can augment minute ventilation and supply supplemental oxygen in spontaneously breathing patients with a simple, non-invasive interface.

  20. The influence of target and patient characteristics on the volume obtained from cone beam CT in lung stereotactic body radiation therapy.

    PubMed

    Liu, Hong-Wei; Khan, Rao; D'Ambrosi, Rafael; Krobutschek, Krista; Nugent, Zoann; Lau, Harold

    2013-03-01

    To investigate the influence of tumor and patient characteristics on the target volume obtained from cone beam CT (CBCT) in lung stereotactic body radiation therapy (SBRT). For a given cohort of 71 patients, the internal target volume (ITV) in CBCT obtained from four different datasets was compared with a reference ITV drawn on a four-dimensional CT (4DCT). The significance of the tumor size, location, relative target motion (RM) and patient's body mass index (BMI) and gender on the adequacy of ITV obtained from CBCT was determined. The median ITV-CBCT was found to be smaller than the ITV-4DCT by 11.8% (range: -49.8 to +24.3%, P<0.001). Small tumors located in the lower lung were found to have a larger RM than large tumors in the upper lung. Tumors located near the central lung had high CT background which reduced the target contrast near the edges. Tumor location close to center vs. periphery was the only significant factor (P=0.046) causing underestimation of ITV in CBCT, rather than RM (P=0.323) and other factors. The current clinical study has identified that the location of tumor is a major source of discrepancy between ITV-CBCT and ITV-4DCT for lung SBRT. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  1. Consensus Guidelines for Delineation of Clinical Target Volume for Intensity-Modulated Pelvic Radiotherapy for the Definitive Treatment of Cervix Cancer

    SciTech Connect

    Lim, Karen; Portelance, Lorraine; Creutzberg, Carien; Juergenliemk-Schulz, Ina M.; Mundt, Arno; Mell, Loren K.; Mayr, Nina; Viswanathan, Akila; Jhingran, Anuja; Erickson, Beth; De Los Santos, Jennifer; Gaffney, David; Yashar, Catheryn; Beriwal, Sushil; Wolfson, Aaron

    2011-02-01

    Purpose: Accurate target definition is vitally important for definitive treatment of cervix cancer with intensity-modulated radiotherapy (IMRT), yet a definition of clinical target volume (CTV) remains variable within the literature. The aim of this study was to develop a consensus CTV definition in preparation for a Phase 2 clinical trial being planned by the Radiation Therapy Oncology Group. Methods and Materials: A guidelines consensus working group meeting was convened in June 2008 for the purposes of developing target definition guidelines for IMRT for the intact cervix. A draft document of recommendations for CTV definition was created and used to aid in contouring a clinical case. The clinical case was then analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with kappa statistics as a measure of agreement between participants. Results: Nineteen experts in gynecological radiation oncology generated contours on axial magnetic resonance images of the pelvis. Substantial STAPLE agreement sensitivity and specificity values were seen for gross tumor volume (GTV) delineation (0.84 and 0.96, respectively) with a kappa statistic of 0.68 (p < 0.0001). Agreement for delineation of cervix, uterus, vagina, and parametria was moderate. Conclusions: This report provides guidelines for CTV definition in the definitive cervix cancer setting for the purposes of IMRT, building on previously published guidelines for IMRT in the postoperative setting.

  2. Ideal target arterial pressure after control of bleeding in a rabbit model of severe traumatic hemorrhagic shock: results from volume loading-based fluid resuscitation.

    PubMed

    Zhao, Xiao-Gang; Jiang, Shou-Yin; Zhang, Mao; Zhou, Guang-Ju; Zhao, Ying-Ying; Yi, Hui-Xing; Jiang, Li-Bing; Wang, Jian-An

    2015-06-15

    Previously reported ideal target mean arterial pressure (MAP) after control of bleeding in traumatic hemorrhagic shock (THS) requires further verification in more clinically related models. The authors explored this issue via gradient volume loading without vasopressor therapy. As certain volume loading can induce secretion of atrial natriuretic peptide (ANP), which has been shown to be protective, the authors also observed its potential role. Fifty male New Zealand rabbits were submitted to 1.5 h of uncontrolled THS (with another eight rabbits assigned to the sham group). After bleeding control, treated rabbits were randomly (n = 10, respectively) resuscitated with blood and Ringer lactate (1:2) to achieve target MAP of 50, 60, 70, 80, and 90 mm Hg within 1 h. During the following 2 h, they were resuscitated toward baseline MAP. Rabbits were observed until 7 h. After resuscitation, infused fluid was lower and oxidative stress injury was milder in the 70 mm Hg group. Fluid volume loaded during the initial hour after hemostasis was negatively correlated with pH, oxygen saturation, and base excess at the end of resuscitation. It also correlated positively with proinflammatory responses in bronchoalveolar lavage fluid at 7 h and 7-h mortality. Moreover, after volume loading, the 80 mm Hg group showed significantly increased serum ANP level, which correlated with the expression of Akt protein in the jejunum at 7 h. In rabbits the ideal target MAP during the initial resuscitation of severe THS after hemostasis was 70 mm Hg. ANP may have a critical role in gut protection. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Verification of Planning Target Volume Settings in Volumetric Modulated Arc Therapy for Stereotactic Body Radiation Therapy by Using In-Treatment 4-Dimensional Cone Beam Computed Tomography

    SciTech Connect

    Takahashi, Wataru; Yamashita, Hideomi; Kida, Satoshi; Masutani, Yoshitaka; Sakumi, Akira; Ohtomo, Kuni; Nakagawa, Keiichi; Haga, Akihiro

    2013-07-01

    Purpose: To evaluate setup error and tumor motion during beam delivery by using 4-dimensional cone beam computed tomography (4D CBCT) and to assess the adequacy of the planning target volume (PTV) margin for lung cancer patients undergoing volumetric modulated arc therapy for stereotactic body radiation therapy (VMAT-SBRT). Methods and Materials: Fifteen lung cancer patients treated by single-arc VMAT-SBRT were selected in this analysis. All patients were treated with an abdominal compressor. The gross tumor volumes were contoured on maximum inspiration and maximum expiration CT datasets from 4D CT respiratory sorting and merged into internal target volumes (ITVs). The PTV margin was isotropically taken as 5 mm. Registration was automatically performed using “pre-3D” CBCT. Treatment was performed with a D95 prescription of 50 Gy delivered in 4 fractions. The 4D tumor locations during beam delivery were determined using in-treatment 4D CBCT images acquired in each fraction. Then, the discrepancy between the actual tumor location and the ITV was evaluated in the lateral, vertical, and longitudinal directions. Results: Overall, 55 4D CBCT sets during VMAT-SBRT were successfully obtained. The amplitude of tumor motion was less than 10 mm in all directions. The average displacements between ITV and actual tumor location during treatment were 0.41 ± 0.93 mm, 0.15 ± 0.58 mm, and 0.60 ± 0.99 mm for the craniocaudal, left-right, and anteroposterior directions, respectively. The discrepancy in each phase did not exceed 5 mm in any direction. Conclusions: With in-treatment 4D CBCT, we confirmed the required PTV margins when the registration for moving target was performed using pre-3D CBCT. In-treatment 4D CBCT is a direct method for quantitatively assessing the intrafractional location of a moving target.

  4. Verification of planning target volume settings in volumetric modulated arc therapy for stereotactic body radiation therapy by using in-treatment 4-dimensional cone beam computed tomography.

    PubMed

    Takahashi, Wataru; Yamashita, Hideomi; Kida, Satoshi; Masutani, Yoshitaka; Sakumi, Akira; Ohtomo, Kuni; Nakagawa, Keiichi; Haga, Akihiro

    2013-07-01

    To evaluate setup error and tumor motion during beam delivery by using 4-dimensional cone beam computed tomography (4D CBCT) and to assess the adequacy of the planning target volume (PTV) margin for lung cancer patients undergoing volumetric modulated arc therapy for stereotactic body radiation therapy (VMAT-SBRT). Fifteen lung cancer patients treated by single-arc VMAT-SBRT were selected in this analysis. All patients were treated with an abdominal compressor. The gross tumor volumes were contoured on maximum inspiration and maximum expiration CT datasets from 4D CT respiratory sorting and merged into internal target volumes (ITVs). The PTV margin was isotropically taken as 5 mm. Registration was automatically performed using "pre-3D" CBCT. Treatment was performed with a D95 prescription of 50 Gy delivered in 4 fractions. The 4D tumor locations during beam delivery were determined using in-treatment 4D CBCT images acquired in each fraction. Then, the discrepancy between the actual tumor location and the ITV was evaluated in the lateral, vertical, and longitudinal directions. Overall, 55 4D CBCT sets during VMAT-SBRT were successfully obtained. The amplitude of tumor motion was less than 10 mm in all directions. The average displacements between ITV and actual tumor location during treatment were 0.41 ± 0.93 mm, 0.15 ± 0.58 mm, and 0.60 ± 0.99 mm for the craniocaudal, left-right, and anteroposterior directions, respectively. The discrepancy in each phase did not exceed 5 mm in any direction. With in-treatment 4D CBCT, we confirmed the required PTV margins when the registration for moving target was performed using pre-3D CBCT. In-treatment 4D CBCT is a direct method for quantitatively assessing the intrafractional location of a moving target. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Comparison of internal target volumes defined on 3-dimensional, 4-dimensonal, and cone-beam CT images of non-small-cell lung cancer

    PubMed Central

    Li, Fengxiang; Li, Jianbin; Ma, Zhifang; Zhang, Yingjie; Xing, Jun; Qi, Huanpeng; Shang, Dongping

    2016-01-01

    Purpose The purpose of this study was to compare the positional and volumetric differences of internal target volumes defined on three-dimensional computed tomography (3DCT), four-dimensional CT (4DCT), and cone-beam CT (CBCT) images of non-small-cell lung cancer (NSCLC). Materials and methods Thirty-one patients with NSCLC sequentially underwent 3DCT and 4DCT simulation scans of the thorax during free breathing. The first CBCT was performed and registered to the planning CT using the bony anatomy registration during radiotherapy. The gross tumor volumes were contoured on the basis of 3DCT, maximum intensity projection (MIP) of 4DCT, and CBCT. CTV3D (clinical target volume), internal target volumes, ITVMIP and ITVCBCT, were defined with a 7 mm margin accounting for microscopic disease. ITV10 mm and ITV5 mm were defined on the basis of CTV3D: ITV10 mm with a 5 mm margin in left–right (LR), anterior–posterior (AP) directions and 10 mm in cranial–caudal (CC) direction; ITV5 mm with an isotropic internal margin (IM) of 5 mm. The differences in the position, size, Dice’s similarity coefficient (DSC) and inclusion relation of different volumes were evaluated. Results The median size ratios of ITV10 mm, ITV5 mm, and ITVMIP to ITVCBCT were 2.33, 1.88, and 1.03, respectively, for tumors in the upper lobe and 2.13, 1.76, and 1.1, respectively, for tumors in the middle-lower lobe. The median DSCs of ITV10 mm, ITV5 mm, ITVMIP, and ITVCBCT were 0.6, 0.66, and 0.83 for all patients. The median percentages of ITVCBCT not included in ITV10 mm, ITV5 mm, and ITVMIP were 0.1%, 1.63%, and 15.21%, respectively, while the median percentages of ITV10 mm, ITV5 mm, and ITVMIP not included in ITVCBCT were 57.08%, 48.89%, and 20.04%, respectively. Conclusion The use of the individual ITV derived from 4DCT merely based on bony registration in radiotherapy may result in a target miss. The ITVs derived from 3DCT with isotropic margins have a good coverage of the ITV from CBCT, but the

  6. Quantification of Trade-Off Between Parotid Gland Sparing and Planning Target Volume Underdosages in Clinically Node-Negative Head-and-Neck Intensity-Modulated Radiotherapy

    SciTech Connect

    Kruijf, Wilhelmus de . E-mail: kruijf.de.w@bvi.nl; Heijmen, Ben; Levendag, Peter C.

    2007-05-01

    Purpose: To quantify the trade-off between parotid gland sparing and planning target volume (PTV) underdosages for head-and-neck intensity-modulated radiotherapy. Methods and Materials: A planning study was performed for 4 patients with either soft palate or tonsil tumors treated with external radiotherapy up to 46 Gy. The trade-off between underdosages in the PTV and sparing of the parotid glands was investigated by systematically varying the optimization objectives for the inverse planning. A new way of presenting dose-volume information allows easy detection of small PTV subvolumes with underdosages that cannot be assessed in conventional cumulative dose-volume histograms. A simple radiobiological model to estimate the control probability for an electively irradiated neck level was developed. Results: The average dose to the parotid glands can decrease by >10 Gy by allowing the PTV to be underdosed in such a way that the radiobiological model predicts a decrease in subclinical disease control probability of (typically) 1% to a few percent. Conclusion: The trade-off between parotid gland sparing and underdosages in the PTV has been quantified by the use of an alternative method to present dose-volume information and by the use of a radiobiological model to predict subclinical disease control probability.

  7. Multimodality imaging with CT, MR and FDG-PET for radiotherapy target volume delineation in oropharyngeal squamous cell carcinoma.

    PubMed

    Bird, David; Scarsbrook, Andrew F; Sykes, Jonathan; Ramasamy, Satiavani; Subesinghe, Manil; Carey, Brendan; Wilson, Daniel J; Roberts, Neil; McDermott, Gary; Karakaya, Ebru; Bayman, Evrim; Sen, Mehmet; Speight, Richard; Prestwich, Robin J D

    2015-11-04

    This study aimed to quantify the variation in oropharyngeal squamous cell carcinoma gross tumour volume (GTV) delineation between CT, MR and FDG PET-CT imaging. A prospective, single centre, pilot study was undertaken where 11 patients with locally advanced oropharyngeal cancers (2 tonsil, 9 base of tongue primaries) underwent pre-treatment, contrast enhanced, FDG PET-CT and MR imaging, all performed in a radiotherapy treatment mask. CT, MR and CT-MR GTVs were contoured by 5 clinicians (2 radiologists and 3 radiation oncologists). A semi-automated segmentation algorithm was used to contour PET GTVs. Volume and positional analyses were undertaken, accounting for inter-observer variation, using linear mixed effects models and contour comparison metrics respectively. Significant differences in mean GTV volume were found between CT (11.9 cm(3)) and CT-MR (14.1 cm(3)), p < 0.006, CT-MR and PET (9.5 cm(3)), p < 0.0009, and MR (12.7 cm(3)) and PET, p < 0.016. Substantial differences in GTV position were found between all modalities with the exception of CT-MR and MR GTVs. A mean of 64 %, 74 % and 77 % of the PET GTVs were included within the CT, MR and CT-MR GTVs respectively. A mean of 57 % of the MR GTVs were included within the CT GTV; conversely a mean of 63 % of the CT GTVs were included within the MR GTV. CT inter-observer variability was found to be significantly higher in terms of position and/or volume than both MR and CT-MR (p < 0.05). Significant differences in GTV volume were found between GTV volumes delineated by radiologists (9.7 cm(3)) and oncologists (14.6 cm(3)) for all modalities (p = 0.001). The use of different imaging modalities produced significantly different GTVs, with no single imaging technique encompassing all potential GTV regions. The use of MR reduced inter-observer variability. These data suggest delineation based on multimodality imaging has the potential to improve accuracy of GTV definition. ISRCTN Registry: ISRCTN

  8. Comparison and Consensus Guidelines for Delineation of Clinical Target Volume for CT- and MR-Based Brachytherapy in Locally Advanced Cervical Cancer

    PubMed Central

    Viswanathan, Akila N.; Erickson, Beth; Gaffney, David K.; Bosch, Walter

    2014-01-01

    Purpose/Objective To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3 Tesla (3T) magnetic resonance (MR) image-based cervical-cancer brachytherapy Materials/Methods Twenty-three gynecologic radiation oncology experts contoured the same 3 cervical-cancer brachytherapy cases: one Stage IIB near-complete response (CR) case with a tandem and ovoid, one Stage IIB partial response (PR) case with ovoid with needles and one Stage IB2 CR case with a ring applicator. CT contours were completed before MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with kappa statistics as a measure of agreement between participants. The conformity index (CI) was calculated for each of the six data sets. Dice coefficients were generated to compare CT and MR contours of the same case. Results For all 3 cases, the mean tumor volume was smaller on MR than on CT (p<0.001). Kappa and CI estimates were slightly higher for CT, indicating a higher level of agreement on CT. DICE coefficients were 89% for the Stage IB2 case with a CR, 74% for the Stage IIB case with a PR, and 57% for the Stage IIB case with a CR. Conclusion When comparing MR- to CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast visible on the images at the time of brachytherapy. The largest difference at the time of brachytherapy was in the case with parametrial extension at diagnosis that had a near-complete response, due to the appearance of the parametria on CT but not on MR. Based on these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at http://www.nrgoncology.org/Resources/ContouringAtlases.aspx. PMID:25304792

  9. SU-E-T-170: Characterization of the Location, Extent, and Proximity to Critical Structures of Target Volumes Provides Detail for Improved Outcome Predictions Among Pancreatic Cancer Patients

    SciTech Connect

    Cheng, Z; Moore, J; Rosati, L; Mian, O; Narang, A; Herman, J; McNutt, T

    2015-06-15

    Purpose: In radiotherapy, size, location and proximity of the target to critical structures influence treatment decisions. It has been shown that proximity of the target predicts dosimetric sparing of critical structures. In addition to dosimetry, precise location of disease has further implications such as tumor invasion, or proximity to major arteries that inhibit surgery. Knowledge of which patients can be converted to surgical candidates by radiation may have high impact on future treat/no-treat decisions. We propose a method to improve our characterization of the location of pancreatic cancer and treatment volume extent with respect to nearby arteries with the goal of developing features to improve clinical predictions and decisions. Methods: Oncospace is a local learning health system that systematically captures clinical outcomes and all aspects of radiotherapy treatment plans, including overlap volume histograms (OVH) – a measure of spatial relationships between two structures. Minimum and maximum distances of PTV and OARs based on OVH, PTV volume, anatomic location by ICD-9 code, and surgical outcome were queried. Normalized distance to center from the left and right kidney was calculated to indicate tumor location and laterality. Distance to critical arteries (celiac, superior mesenteric, common hepatic) is validated by surgical status (borderline resectable, locally advanced converted to resectable). Results: There were 205 pancreas stereotactic body radiotherapy patients treated from 2009–2015 queried. Location/laterality of tumor based on kidney OVH show strong trends between location by OVH and by ICD-9. Compared to the locally advanced group, the borderline resectable group showed larger geometrical distance from critical arteries (p=0.03). Conclusion: Our platform enabled analysis of shape/size-location relationships. These data suggest that PTV volume and attention to distance between PTVs and surrounding OARs and major arteries may be

  10. Intensity modulated radiation therapy (IMRT): differences in target volumes and improvement in clinically relevant doses to small bowel in rectal carcinoma

    PubMed Central

    2011-01-01

    bony landmark-derived fields, without incurring penalty with respect to adjacent organs-at-risk. Conclusions For rectal carcinoma, IMRT, compared to 3DCRT, yielded plans superior with respect to target coverage, homogeneity, and conformality, while lowering dose to adjacent organs-at-risk. This is achieved despite treating larger volumes, raising the possibility of a clinically-relevant improvement in the therapeutic ratio through the use of IMRT with a belly-board apparatus. PMID:21651775

  11. Variations in target volume definition for postoperative radiotherapy in stage III non-small-cell lung cancer: analysis of an international contouring study.

    PubMed

    Spoelstra, Femke O B; Senan, Suresh; Le Péchoux, Cecile; Ishikura, Satoshi; Casas, Francesc; Ball, David; Price, Allan; De Ruysscher, Dirk; van Sörnsen de Koste, John R

    2010-03-15

    Postoperative radiotherapy (PORT) in patients with completely resected non-small-cell lung cancer with mediastinal involvement is controversial because of the failure of earlier trials to demonstrate a survival benefit. Improved techniques may reduce toxicity, but the treatment fields used in routine practice have not been well studied. We studied routine target volumes used by international experts and evaluated the impact of a contouring protocol developed for a new prospective study, the Lung Adjuvant Radiotherapy Trial (Lung ART). Seventeen thoracic radiation oncologists were invited to contour their routine clinical target volumes (CTV) for 2 representative patients using a validated CD-ROM-based contouring program. Subsequently, the Lung ART study protocol was provided, and both cases were contoured again. Variations in target volumes and their dosimetric impact were analyzed. Routine CTVs were received for each case from 10 clinicians, whereas six provided both routine and protocol CTVs for each case. Routine CTVs varied up to threefold between clinicians, but use of the Lung ART protocol significantly decreased variations. Routine CTVs in a postlobectomy patient resulted in V(20) values ranging from 12.7% to 54.0%, and Lung ART protocol CTVs resulted in values of 20.6% to 29.2%. Similar results were seen for other toxicity parameters and in the postpneumectomy patient. With the exception of upper paratracheal nodes, protocol contouring improved coverage of the required nodal stations. Even among experts, significant interclinician variations are observed in PORT fields. Inasmuch as contouring variations can confound the interpretation of PORT results, mandatory quality assurance procedures have been incorporated into the current Lung ART study. Copyright 2010 Elsevier Inc. All rights reserved.

  12. Variations in Target Volume Definition for Postoperative Radiotherapy in Stage III Non-Small-Cell Lung Cancer: Analysis of an International Contouring Study

    SciTech Connect

    Spoelstra, Femke; Senan, Suresh; Le Pechoux, Cecile; Ishikura, Satoshi; Casas, Francesc; Ball, David; Price, Allan; De Ruysscher, Dirk; Soernsen de Koste, John R. van

    2010-03-15

    Purpose: Postoperative radiotherapy (PORT) in patients with completely resected non-small-cell lung cancer with mediastinal involvement is controversial because of the failure of earlier trials to demonstrate a survival benefit. Improved techniques may reduce toxicity, but the treatment fields used in routine practice have not been well studied. We studied routine target volumes used by international experts and evaluated the impact of a contouring protocol developed for a new prospective study, the Lung Adjuvant Radiotherapy Trial (Lung ART). Methods and Materials: Seventeen thoracic radiation oncologists were invited to contour their routine clinical target volumes (CTV) for 2 representative patients using a validated CD-ROM-based contouring program. Subsequently, the Lung ART study protocol was provided, and both cases were contoured again. Variations in target volumes and their dosimetric impact were analyzed. Results: Routine CTVs were received for each case from 10 clinicians, whereas six provided both routine and protocol CTVs for each case. Routine CTVs varied up to threefold between clinicians, but use of the Lung ART protocol significantly decreased variations. Routine CTVs in a postlobectomy patient resulted in V{sub 20} values ranging from 12.7% to 54.0%, and Lung ART protocol CTVs resulted in values of 20.6% to 29.2%. Similar results were seen for other toxicity parameters and in the postpneumectomy patient. With the exception of upper paratracheal nodes, protocol contouring improved coverage of the required nodal stations. Conclusion: Even among experts, significant interclinician variations are observed in PORT fields. Inasmuch as contouring variations can confound the interpretation of PORT results, mandatory quality assurance procedures have been incorporated into the current Lung ART study.

  13. 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.

  14. The dosimetric impact of daily setup error on target volumes and surrounding normal tissue in the treatment of prostate cancer with intensity-modulated radiation therapy

    SciTech Connect

    Algan, Ozer; Jamgade, Ambarish; Ali, Imad; Christie, Alana; Thompson, J. Spencer; Thompson, David; Ahmad, Salahuddin; Herman, Terence

    2012-01-01

    The purpose of this study was to evaluate the impact of daily setup error and interfraction organ motion on the overall dosimetric radiation treatment plans. Twelve patients undergoing definitive intensity-modulated radiation therapy (IMRT) treatments for prostate cancer were evaluated in this institutional review board-approved study. Each patient had fiducial markers placed into the prostate gland before treatment planning computed tomography scan. IMRT plans were generated using the Eclipse treatment planning system. Each patient was treated to a dose of 8100 cGy given in 45 fractions. In this study, we retrospectively created a plan for each treatment day that had a shift available. To calculate the dose, the patient would have received under this plan, we mathematically 'negated' the shift by moving the isocenter in the exact opposite direction of the shift. The individualized daily plans were combined to generate an overall plan sum. The dose distributions from these plans were compared with the treatment plans that were used to treat the patients. Three-hundred ninety daily shifts were negated and their corresponding plans evaluated. The mean isocenter shift based on the location of the fiducial markers was 3.3 {+-} 6.5 mm to the right, 1.6 {+-} 5.1 mm posteriorly, and 1.0 {+-} 5.0 mm along the caudal direction. The mean D95 doses for the prostate gland when setup error was corrected and uncorrected were 8228 and 7844 cGy (p < 0.002), respectively, and for the planning target volume (PTV8100) was 8089 and 7303 cGy (p < 0.001), respectively. The mean V95 values when patient setup was corrected and uncorrected were 99.9% and 87.3%, respectively, for the PTV8100 volume (p < 0.0001). At an individual patient level, the difference in the D95 value for the prostate volume could be >1200 cGy and for the PTV8100 could approach almost 2000 cGy when comparing corrected against uncorrected plans. There was no statistically significant difference in the D35 parameter

  15. Respiratory-gated (4D) contrast-enhanced FDG PET-CT for radiotherapy planning of lower oesophageal carcinoma: feasibility and impact on planning target volume.

    PubMed

    Scarsbrook, Andrew; Ward, Gillian; Murray, Patrick; Goody, Rebecca; Marshall, Karen; McDermott, Garry; Prestwich, Robin; Radhakrishna, Ganesh

    2017-10-04

    To assess the feasibility and potential impact on target delineation of respiratory-gated (4D) contrast-enhanced (18)Fluorine fluorodeoxyglucose (FDG) positron emission tomography - computed tomography (PET-CT), in the treatment planning position, for a prospective cohort of patients with lower third oesophageal cancer. Fifteen patients were recruited into the study. Imaging included 4D PET-CT, 3D PET-CT, endoscopic ultrasound and planning 4D CT. Target volume delineation was performed on 4D CT, 4D CT with co-registered 3D PET and 4D PET-CT. Planning target volumes (PTV) generated with 4D CT (PTV4DCT), 4D CT co-registered with 3D PET-CT (PTV3DPET4DCT) and 4D PET-CT (PTV4DPETCT) were compared with multiple positional metrics. Mean PTV4DCT, PTV3DPET4DCT and PTV4DPETCT were 582.4 ± 275.1 cm(3), 472.5 ± 193.1 cm(3) and 480.6 ± 236.9 cm(3) respectively (no significant difference). Median DICE similarity coefficients comparing PTV4DCT with PTV3DPET4DCT, PTV4DCT with PTV4DPETCT and PTV3DPET4DCT with PTV4DPETCT were 0.85 (range 0.65-0.9), 0.85 (range 0.69-0.9) and 0.88 (range 0.79-0.9) respectively. The median sensitivity index for overlap comparing PTV4DCT with PTV3DPET4DCT, PTV4DCT with PTV4DPETCT and PTV3DPET4DCT with PTV4DPETCT were 0.78 (range 0.65-0.9), 0.79 (range 0.65-0.9) and 0.89 (range 0.68-0.94) respectively. Planning 4D PET-CT is feasible with careful patient selection. PTV generated using 4D CT, 3D PET-CT and 4D PET-CT were of similar volume, however, overlap analysis demonstrated that approximately 20% of PTV3DPETCT and PTV4DPETCT are not included in PTV4DCT, leading to under-coverage of target volume and a potential geometric miss. Additionally, differences between PTV3DPET4DCT and PTV4DPETCT suggest a potential benefit for 4D PET-CT. ClinicalTrials.gov Identifier - NCT02285660 (Registered 21/10/2014).

  16. Intra-tumour 18F-FDG uptake heterogeneity decreases the reliability on target volume definition with positron emission tomography/computed tomography imaging.

    PubMed

    Dong, Xinzhe; Wu, Peipei; Sun, Xiaorong; Li, Wenwu; Wan, Honglin; Yu, Jinming; Xing, Ligang

    2015-06-01

    This study aims to explore whether the intra-tumour (18) F-fluorodeoxyglucose (FDG) uptake heterogeneity affects the reliability of target volume definition with FDG positron emission tomography/computed tomography (PET/CT) imaging for nonsmall cell lung cancer (NSCLC) and squamous cell oesophageal cancer (SCEC). Patients with NSCLC (n = 50) or SCEC (n = 50) who received (18)F-FDG PET/CT scanning before treatments were included in this retrospective study. Intra-tumour FDG uptake heterogeneity was assessed by visual scoring, the coefficient of variation (COV) of the standardised uptake value (SUV) and the image texture feature (entropy). Tumour volumes (gross tumour volume (GTV)) were delineated on the CT images (GTV(CT)), the fused PET/CT images (GTV(PET-CT)) and the PET images, using a threshold at 40% SUV(max) (GTV(PET40%)) or the SUV cut-off value of 2.5 (GTV(PET2.5)). The correlation between the FDG uptake heterogeneity parameters and the differences in tumour volumes among GTV(CT), GTV(PET-CT), GTV(PET40%) and GTV(PET2.5) was analysed. For both NSCLC and SCEC, obvious correlations were found between uptake heterogeneity, SUV or tumour volumes. Three types of heterogeneity parameters were consistent and closely related to each other. Substantial differences between the four methods of GTV definition were found. The differences between the GTV correlated significantly with PET heterogeneity defined with the visual score, the COV or the textural feature-entropy for NSCLC and SCEC. In tumours with a high FDG uptake heterogeneity, a larger GTV delineation difference was found. Advance image segmentation algorithms dealing with tracer uptake heterogeneity should be incorporated into the treatment planning system. © 2015 The Royal Australian and New Zealand College of Radiologists.

  17. RTOG Sarcoma Radiation Oncologists Reach Consensus on Gross Tumor Volume and Clinical Target Volume on Computed Tomographic Images for Preoperative Radiotherapy of Primary Soft Tissue Sarcoma of Extremity in Radiation Therapy Oncology Group Studies

    SciTech Connect

    Wang Dian; Bosch, Walter; Roberge, David; Finkelstein, Steven E.; Petersen, Ivy; Haddock, Michael; Chen, Yen-Lin E.; Saito, Naoyuki G.; Kirsch, David G.; Hitchcock, Ying J.; Wolfson, Aaron H.; DeLaney, Thomas F.

    2011-11-15

    Objective: To develop a Radiation Therapy Oncology Group (RTOG) atlas delineating gross tumor volume (GTV) and clinical target volume (CTV) to be used for preoperative radiotherapy of primary extremity soft tissue sarcoma (STS). Methods and Materials: A consensus meeting was held during the RTOG meeting in January 2010 to reach agreement about GTV and CTV delineation on computed tomography (CT) images for preoperative radiotherapy of high-grade large extremity STS. Data were presented to address the local extension of STS. Extensive discussion ensued to develop optimal criteria for GTV and CTV delineation on CT images. Results: A consensus was reached on appropriate CT-based GTV and CTV. The GTV is gross tumor defined by T1 contrast-enhanced magnetic resonance images. Fusion of magnetic resonance and images is recommended to delineate the GTV. The CTV for high-grade large STS typically includes the GTV plus 3-cm margins in the longitudinal directions. If this causes the field to extend beyond the compartment, the field can be shortened to include the end of a compartment. The radial margin from the lesion should be 1.5 cm, including any portion of the tumor not confined by an intact fascial barrier, bone, or skin surface. Conclusion: The consensus on GTV and CTV for preoperative radiotherapy of high-grade large extremity STS is available as web-based images and in a descriptive format through the RTOG. This is expected to improve target volume consistency and allow for rigorous evaluation of the benefits and risks of such treatment.

  18. Measurement of Interfraction Variations in Position and Size of Target Volumes in Stereotactic Body Radiotherapy for Lung Cancer

    SciTech Connect

    Matsugi, Kiyotomo; Narita, Yuichiro Sawada, Akira; Nakamura, Mitsuhiro; Miyabe, Yuki; Matsuo, Yukinori; Narabayashi, Masaru; Norihisa, Yoshiki; Mizowaki, Takashi; Hiraoka, Masahiro

    2009-10-01

    Purpose: To investigate the interfraction variations in volume, motion range, and position of the gross tumor volume (GTV) in hypofractionated stereotactic body radiotherapy (SBRT) for lung cancer using four-dimensional computed tomography. Methods and Materials: Four-dimensional computed tomography scans were acquired for 8 patients once at treatment planning and twice during the SBRT period using a stereotactic body frame. The image registration was performed to correct setup errors for clinical four-dimensional computed tomography. The interfraction variations in volume, motion range, and position of GTV were computed at end-inhalation (EI) and end-exhalation (EE). Results: The random variations in the GTV were 0.59 cm{sup 3} at EI and 0.53 cm{sup 3} at EE, and the systematic variations were 3.04 cm{sup 3} at EI and 3.21 cm{sup 3} at EE. No significant variations in GTV were found during the SBRT sessions (p = .301 at EI and p = .081 at EE). The random variations in GTV motion range for the upper lobe in the craniocaudal direction were within 1.0 mm and for the lower lobe was 3.4 mm. The interfraction variations in the GTV centroid position in the anteroposterior and craniocaudal directions were mostly larger than in the right-left direction; however, no significant displacement was observed among the sessions in any direction. Conclusion: For patients undergoing hypofractionated SBRT, interfraction variations in GTV, motion range, and position mainly remained small. An additional approach is needed to assess the margin size.

  19. Impact of PET and MRI threshold-based tumor volume segmentation on patient-specific targeted radionuclide therapy dosimetry using CLR1404

    NASA Astrophysics Data System (ADS)

    Besemer, Abigail E.; Titz, Benjamin; Grudzinski, Joseph J.; Weichert, Jamey P.; Kuo, John S.; Robins, H. Ian; Hall, Lance T.; Bednarz, Bryan P.

    2017-08-01

    Variations in tumor volume segmentation methods in targeted radionuclide therapy (TRT) may lead to dosimetric uncertainties. This work investigates the impact of PET and MRI threshold-based tumor segmentation on TRT dosimetry in patients with primary and metastatic brain tumors. In this study, PET/CT images of five brain cancer patients were acquired at 6, 24, and 48 h post-injection of 124I-CLR1404. The tumor volume was segmented using two standardized uptake value (SUV) threshold levels, two tumor-to-background ratio (TBR) threshold levels, and a T1 Gadolinium-enhanced MRI threshold. The dice similarity coefficient (DSC), jaccard similarity coefficient (JSC), and overlap volume (OV) metrics were calculated to compare differences in the MRI and PET contours. The therapeutic 131I-CLR1404 voxel-level dose distribution was calculated from the 124I-CLR1404 activity distribution using RAPID, a Geant4 Monte Carlo internal dosimetry platform. The TBR, SUV, and MRI tumor volumes ranged from 2.3-63.9 cc, 0.1-34.7 cc, and 0.4-11.8 cc, respectively. The average  ±  standard deviation (range) was 0.19  ±  0.13 (0.01-0.51), 0.30  ±  0.17 (0.03-0.67), and 0.75  ±  0.29 (0.05-1.00) for the JSC, DSC, and OV, respectively. The DSC and JSC values were small and the OV values were large for both the MRI-SUV and MRI-TBR combinations because the regions of PET uptake were generally larger than the MRI enhancement. Notable differences in the tumor dose volume histograms were observed for each patient. The mean (standard deviation) 131I-CLR1404 tumor doses ranged from 0.28-1.75 Gy GBq-1 (0.07-0.37 Gy GBq-1). The ratio of maximum-to-minimum mean doses for each patient ranged from 1.4-2.0. The tumor volume and the interpretation of the tumor dose is highly sensitive to the imaging modality, PET enhancement metric, and threshold level used for tumor volume segmentation. The large variations in tumor doses clearly demonstrate the need for standard

  20. Variation in the Gross Tumor Volume and Clinical Target Volume for Preoperative Radiotherapy of Primary Large High-Grade Soft Tissue Sarcoma of the Extremity Among RTOG Sarcoma Radiation Oncologists

    SciTech Connect

    Wang Dian; Bosch, Walter; Kirsch, David G.; Al Lozi, Rawan; El Naqa, Issam; Roberge, David; Finkelstein, Steven E.; Petersen, Ivy; Haddock, Michael; Chen, Yen-Lin E.; Saito, Naoyuki G.; Hitchcock, Ying J.; Wolfson, Aaron H.; DeLaney, Thomas F.

    2011-12-01

    Purpose: To evaluate variability in the definition of preoperative radiotherapy gross tumor volume (GTV) and clinical target volume (CTV) delineated by sarcoma radiation oncologists. Methods and Materials: Extremity sarcoma planning CT images along with the corresponding diagnostic MRI from two patients were distributed to 10 Radiation Therapy Oncology Group sarcoma radiation oncologists with instructions to define GTV and CTV using standardized guidelines. The CT data with contours were then returned for central analysis. Contours representing statistically corrected 95% (V95) and 100% (V100) agreement were computed for each structure. Results: For the GTV, the minimum, maximum, mean (SD) volumes (mL) were 674, 798, 752 {+-} 35 for the lower extremity case and 383, 543, 447 {+-} 46 for the upper extremity case. The volume (cc) of the union, V95 and V100 were 882, 761, and 752 for the lower, and 587, 461, and 455 for the upper extremity, respectively. The overall GTV agreement was judged to be almost perfect in both lower and upper extremity cases (kappa = 0.9 [p < 0.0001] and kappa = 0.86 [p < 0.0001]). For the CTV, the minimum, maximum, mean (SD) volumes (mL) were 1145, 1911, 1605 {+-} 211 for the lower extremity case and 637, 1246, 1006 {+-} 180 for the upper extremity case. The volume (cc) of the union, V95, and V100 were 2094, 1609, and 1593 for the lower, and 1533, 1020, and 965 for the upper extremity cases, respectively. The overall CTV agreement was judged to be almost perfect in the lower extremity case (kappa = 0.85 [p < 0.0001]) but only substantial in the upper extremity case (kappa = 0.77 [p < 0.0001]). Conclusions: Almost perfect agreement existed in the GTV of these two representative cases. Tshere was no significant disagreement in the CTV of the lower extremity, but variation in the CTV of upper extremity was seen, perhaps related to the positional differences between the planning CT and the diagnostic MRI.

  1. Evaluation of the cone beam CT for internal target volume localization in lung stereotactic radiotherapy in comparison with 4D MIP images.

    PubMed

    Wang, Lu; Chen, Xiaoming; Lin, Mu-Han; Xue, Jun; Lin, Teh; Fan, Jiajin; Jin, Lihui; Ma, Charlie M

    2013-11-01

    To investigate whether the three-dimensional cone-beam CT (CBCT) is clinically equivalent to the four-dimensional computed tomography (4DCT) maximum intensity projection (MIP) reconstructed images for internal target volume (ITV) localization in image-guided lung stereotactic radiotherapy. A ball-shaped polystyrene phantom with built-in cube, sphere, and cone of known volumes was attached to a motor-driven platform, which simulates a sinusoidal movement with changeable motion amplitude and frequency. Target motion was simulated in the patient in a superior-inferior (S-I) direction with three motion periods and 2 cm peak-to-peak amplitudes. The Varian onboard Exact-Arms kV CBCT system and the GE LightSpeed four-slice CT integrated with the respiratory-position-management 4DCT scanner were used to scan the moving phantom. MIP images were generated from the 4DCT images. The clinical equivalence of the two sets of images was evaluated by comparing the extreme locations of the moving objects along the motion direction, the centroid position of the ITV, and the ITV volumes that were contoured automatically by Velocity or calculated with an imaging gradient method. The authors compared the ITV volumes determined by the above methods with those theoretically predicted by taking into account the physical object dimensions and the motion amplitudes. The extreme locations were determined by the gradient method along the S-I axis through the center of the object. The centroid positions were determined by autocenter functions. The effect of motion period on the volume sizes was also studied. It was found that the extreme locations of the objects determined from the two image modalities agreed with each other satisfactorily. They were not affected by the motion period. The average difference between the two modalities in the extreme locations was 0.68% for the cube, 1.35% for the sphere, and 0.5% for the cone, respectively. The maximum difference in the centroid position of the

  2. Evaluation of the cone beam CT for internal target volume localization in lung stereotactic radiotherapy in comparison with 4D MIP images

    SciTech Connect

    Wang, Lu; Chen, Xiaoming; Lin, Mu-Han; Lin, Teh; Fan, Jiajin; Jin, Lihui; Ma, Charlie M.; Xue, Jun

    2013-11-15

    Purpose: To investigate whether the three-dimensional cone-beam CT (CBCT) is clinically equivalent to the four-dimensional computed tomography (4DCT) maximum intensity projection (MIP) reconstructed images for internal target volume (ITV) localization in image-guided lung stereotactic radiotherapy.Methods: A ball-shaped polystyrene phantom with built-in cube, sphere, and cone of known volumes was attached to a motor-driven platform, which simulates a sinusoidal movement with changeable motion amplitude and frequency. Target motion was simulated in the patient in a superior-inferior (S-I) direction with three motion periods and 2 cm peak-to-peak amplitudes. The Varian onboard Exact-Arms kV CBCT system and the GE LightSpeed four-slice CT integrated with the respiratory-position-management 4DCT scanner were used to scan the moving phantom. MIP images were generated from the 4DCT images. The clinical equivalence of the two sets of images was evaluated by comparing the extreme locations of the moving objects along the motion direction, the centroid position of the ITV, and the ITV volumes that were contoured automatically by Velocity or calculated with an imaging gradient method. The authors compared the ITV volumes determined by the above methods with those theoretically predicted by taking into account the physical object dimensions and the motion amplitudes. The extreme locations were determined by the gradient method along the S-I axis through the center of the object. The centroid positions were determined by autocenter functions. The effect of motion period on the volume sizes was also studied.Results: It was found that the extreme locations of the objects determined from the two image modalities agreed with each other satisfactorily. They were not affected by the motion period. The average difference between the two modalities in the extreme locations was 0.68% for the cube, 1.35% for the sphere, and 0.5% for the cone, respectively. The maximum difference in the

  3. Impact of Including Peritumoral Edema in Radiotherapy Target Volume on Patterns of Failure in Glioblastoma following Temozolomide-based Chemoradiotherapy

    PubMed Central

    Choi, Seo Hee; Kim, Jun Won; Chang, Jee Suk; Cho, Jae Ho; Kim, Se Hoon; Chang, Jong Hee; Suh, Chang-Ok

    2017-01-01

    We assessed the impact of including peritumoral edema in radiotherapy volumes on recurrence patterns among glioblastoma multiforme (GBM) patients treated with standard chemoradiotherapy (CRT). We analyzed 167 patients with histologically confirmed GBM who received temozolomide (TMZ)-based CRT between May 2006 and November 2012. The study cohort was divided into edema (+) (n = 130) and edema (−) (n = 37) groups, according to whether the entire peritumoral edema was included. At a median follow-up of 20 months (range, 2–99 months), 118 patients (71%) experienced progression/recurrence (infield: 69%; marginal: 26%; outfield: 16%; CSF seeding: 12%). The median overall survival and progression-free survival were 20 months and 15 months, respectively. The marginal failure rate was significantly greater in the edema (−) group (37% vs. 22%, p = 0.050). Among 33 patients who had a favorable prognosis (total resection and MGMT-methylation), the difference in the marginal failure rates was increased (40% vs. 14%, p = 0.138). Meanwhile, treatment of edema did not significantly increase the incidence of pseudoprogression/radiation necrosis (edema (−) 49% vs. (+) 37%, p = 0.253). Inclusion of peritumoral edema in the radiotherapy volume can reduce marginal failures following TMZ-based CRT without increasing pseudoprogression/radiation necrosis. PMID:28176884

  4. Antioxidants and NOS inhibitors selectively targets manganese-induced cell volume via Na-K-Cl cotransporter-1 in astrocytes.

    PubMed

    Alahmari, Khalid A; Prabhakaran, Harini; Prabhakaran, Krishnan; Chandramoorthy, Harish C; Ramugounder, Ramakrishnan

    2015-06-12

    Manganese has shown to be involved in astrocyte swelling. Several factors such as transporters, exchangers and ion channels are attributed to astrocyte swelling as a result in the deregulation of cell volume. Products of oxidation and nitration have been implied to be involved in the pathophysiology of swelling; however, the direct link and mechanism of manganese induced astrocyte swelling has not been fully elucidated. In the current study, we used rat primary astrocyte cultures to investigate the activation of Na-K-Cl cotransporter-1 (NKCC1) a downstream mechanism for free radical induced astrocyte swelling as a result of manganese toxicity. Our results showed manganese, oxidants and NO donors as potent inducer of oxidation and nitration of NKCC1. Our results further confirmed that manganese (50 μM) increased the total protein, phosphorylation and activity of NKCC1 as well as cell volume (p < 0.05 vs. control). NKCC1 inhibitor (bumetanide), NKCC1-siRNA, antioxidants; DMTU, MnTBAP, tempol, catalase and Vit-E, NOS inhibitor; L-NAME, peroxinitrite scavenger; uric acid all significantly reversed the effects of NKCC1 activation (p < 0.05). From the current investigation we infer that manganese or oxidants and NO induced activation, oxidation/nitration of NKCC1 play an important role in the astrocyte swelling.

  5. Dosimetric accuracy of a treatment planning system for actively scanned proton beams and small target volumes: Monte Carlo and experimental validation

    NASA Astrophysics Data System (ADS)

    Magro, G.; Molinelli, S.; Mairani, A.; Mirandola, A.; Panizza, D.; Russo, S.; Ferrari, A.; Valvo, F.; Fossati, P.; Ciocca, M.

    2015-09-01

    This study was performed to evaluate the accuracy of a commercial treatment planning system (TPS), in optimising proton pencil beam dose distributions for small targets of different sizes (5-30 mm side) located at increasing depths in water. The TPS analytical algorithm was benchmarked against experimental data and the FLUKA Monte Carlo (MC) code, previously validated for the selected beam-line. We tested the Siemens syngo® TPS plan optimisation module for water cubes fixing the configurable parameters at clinical standards, with homogeneous target coverage to a 2 Gy (RBE) dose prescription as unique goal. Plans were delivered and the dose at each volume centre was measured in water with a calibrated PTW Advanced Markus® chamber. An EBT3® film was also positioned at the phantom entrance window for the acquisition of 2D dose maps. Discrepancies between TPS calculated and MC simulated values were mainly due to the different lateral spread modeling and resulted in being related to the field-to-spot size ratio. The accuracy of the TPS was proved to be clinically acceptable in all cases but very small and shallow volumes. In this contest, the use of MC to validate TPS results proved to be a reliable procedure for pre-treatment plan verification.

  6. Toward Semi-automated Assessment of Target Volume Delineation in Radiotherapy Trials: The SCOPE 1 Pretrial Test Case

    SciTech Connect

    Gwynne, Sarah; Spezi, Emiliano; Wills, Lucy; Nixon, Lisette; Hurt, Chris; Joseph, George; Evans, Mererid; Griffiths, Gareth; Crosby, Tom; Staffurth, John

    2012-11-15

    Purpose: To evaluate different conformity indices (CIs) for use in the analysis of outlining consistency within the pretrial quality assurance (Radiotherapy Trials Quality Assurance [RTTQA]) program of a multicenter chemoradiation trial of esophageal cancer and to make recommendations for their use in future trials. Methods and Materials: The National Cancer Research Institute SCOPE 1 trial is an ongoing Cancer Research UK-funded phase II/III randomized controlled trial of chemoradiation with capecitabine and cisplatin with or without cetuximab for esophageal cancer. The pretrial RTTQA program included a detailed radiotherapy protocol, an educational package, and a single mid-esophageal tumor test case that were sent to each investigator to outline. Investigator gross tumor volumes (GTVs) were received from 50 investigators in 34 UK centers, and CERR (Computational Environment for Radiotherapy Research) was used to perform an assessment of each investigator GTV against a predefined gold-standard GTV using different CIs. A new metric, the local conformity index (l-CI), that can localize areas of maximal discordance was developed. Results: The median Jaccard conformity index (JCI) was 0.69 (interquartile range, 0.62-0.70), with 14 of 50 investigators (28%) achieving a JCI of 0.7 or greater. The median geographical miss index was 0.09 (interquartile range, 0.06-0.16), and the mean discordance index was 0.27 (95% confidence interval, 0.25-0.30). The l-CI was highest in the middle section of the volume, where the tumor was bulky and more easily definable, and identified 4 slices where fewer than 20% of investigators achieved an l-CI of 0.7 or greater. Conclusions: The available CIs analyze different aspects of a gold standard-observer variation, with JCI being the most useful as a single metric. Additional information is provided by the l-CI and can focus the efforts of the RTTQA team in these areas, possibly leading to semi-automated outlining assessment.

  7. Contribution of {sup 68}Ga-DOTATOC PET/CT to Target Volume Delineation of Skull Base Meningiomas Treated With Stereotactic Radiation Therapy

    SciTech Connect

    Graf, Reinhold; Nyuyki, Fonyuy; Steffen, Ingo G.; Michel, Roger; Fahdt, Daniel; Wust, Peter; Brenner, Winfried; Budach, Volker; Wurm, Reinhard; Plotkin, Michail

    2013-01-01

    Purpose: To investigate the potential impact of {sup 68}Ga-DOTATOC positron emission tomography ({sup 68}Ga-DOTATOC-PET) in addition to magnetic resonance imaging (MRI) and computed tomography (CT) for retrospectively assessing the gross tumor volume (GTV) delineation of meningiomas of the skull base in patients treated with fractionated stereotactic radiation therapy (FSRT). Methods and Materials: The study population consisted of 48 patients with 54 skull base meningiomas, previously treated with FSRT. After scans were coregistered, the GTVs were first delineated with MRI and CT data (GTV{sub MRI/CT}) and then by PET (GTV{sub PET}) data. The overlapping regions of both datasets resulted in the GTV{sub common}, which was enlarged to the GTV{sub final} by adding volumes defined by only one of the complementary modalities (GTV{sub MRI/CT-added} or GTV{sub PET-added}). We then evaluated the contribution of conventional imaging modalities (MRI, CT) and {sup 68}Ga-DOTATOC-PET to the GTV{sub final}, which was used for planning purposes. Results: Forty-eight of the 54 skull base lesions in 45 patients showed increased {sup 68}Ga-DOTATOC uptake and were further analyzed. The mean GTV{sub MRI/CT} and GTV{sub PET} were approximately 21 cm{sup 3} and 25 cm{sup 3}, with a common volume of approximately 15 cm{sup 3}. PET contributed a mean additional GTV of approximately 1.5 cm{sup 3} to the common volume (16% {+-} 34% of the GTV{sub common}). Approximately 4.5 cm{sup 3} of the GTV{sub MRI/CT} was excluded from the contribution to the common volume. The resulting mean GTV{sub final} was significantly smaller than both the GTV{sub MRI/CT} and the GTV{sub PET}. Compared with the initial GTV{sub MRI/CT}, the addition of {sup 68}Ga-DOTATOC-PET resulted in more than 10% modification of the size of the GTV{sub final} in 32 (67%) meningiomas Conclusions: {sup 68}Ga-DOTATOC-PET/CT seems to improve the target volume delineation in skull base meningiomas, often leading to a reduction of

  8. Sci-Thur AM: Planning - 06: Planning target volume margin suitability in lung stereotactic body radiation therapy: A preliminary evaluation using cone-beam computed tomography.

    PubMed

    Mathew, L; Swaminath, A; Szabo, J; Wierzbicki, M

    2012-07-01

    Stereotactic body radiation therapy (SBRT) requires precise delivery of radiation to the target; intra- and inter-fraction lung tumour motion may adversely impact local tumour control. The purpose of this study was to retrospectively evaluate the impact of planning target volume (PTV) margin size on the coverage of the internal target volume (ITV) as localized in pre- and post-treatment cone-beam computed tomography (CBCT) images. Data from two patients undergoing SBRT were evaluated. For planning, free-breathing and 4DCT scans were performed, and used to contour the ITV. A 5mm margin was added to create the PTV. During treatment, 14 CBCTs were collected pre- and post-beam delivery. A data set comprising the average 4DCT intensities where available and treatment planning CT intensities for voxels that were beyond the field of view of the 4DCT was constructed. Registration of the combined planning image to each CBCT was performed using a deformable image registration algorithm. The transformations aligning the combined planning image with the CBCTs were applied to the planning ITV to obtain the treatment ITVs. For each CBCT, the fraction of treatment ITV within the PTV was determined using Boolean logic. This was repeated for various PTV margins ranging from 0 to 10 mm at 1mm intervals. The 3 and 5 mm PTV margins covered 95.1 ± 5.9% and 99.0 ± 2.0% of the ITV, respectively. Analysis of additional patients will be performed to confirm these preliminary results, which reinforce the use of a 5mm PTV margin for lung SBRT. © 2012 American Association of Physicists in Medicine.

  9. Assessment of Planning Target Volume Margins for Intensity-Modulated Radiotherapy of the Prostate Gland: Role of Daily Inter- and Intrafraction Motion

    SciTech Connect

    Tanyi, James A.; He, Tongming; Summers, Paige A.; Mburu, Ruth G.; Kato, Catherine M.; Rhodes, Stephen M.; Hung, Arthur Y.; Fuss, Martin

    2010-12-01

    Purpose: To determine planning target volume margins for prostate intensity-modulated radiotherapy based on inter- and intrafraction motion using four daily localization techniques: three-point skin mark alignment, volumetric imaging with bony landmark registration, volumetric imaging with implanted fiducial marker registration, and implanted electromagnetic transponders (beacons) detection. Methods and Materials: Fourteen patients who underwent definitive intensity-modulated radiotherapy for prostate cancer formed the basis of this study. Each patient was implanted with three electromagnetic transponders and underwent a course of 39 treatment fractions. Daily localization was based on three-point skin mark alignment followed by transponder detection and patient repositioning. Transponder positioning was verified by volumetric imaging with cone-beam computed tomography of the pelvis. Relative motion between the prostate gland and bony anatomy was quantified by offline analyses of daily cone-beam computed tomography. Intratreatment organ motion was monitored continuously by the Calypso (registered) System for quantification of intrafraction setup error. Results: As expected, setup error (that is, inter- plus intrafraction motion, unless otherwise stated) was largest with skin mark alignment, requiring margins of 7.5 mm, 11.4 mm, and 16.3 mm, in the lateral (LR), longitudinal (SI), and vertical (AP) directions, respectively. Margin requirements accounting for intrafraction motion were smallest for transponder detection localization techniques, requiring margins of 1.4 mm (LR), 2.6 mm (SI), and 2.3 mm (AP). Bony anatomy alignment required 2.1 mm (LR), 9.4 mm (SI), and 10.5 mm (AP), whereas image-guided marker alignment required 2.8 mm (LR), 3.7 mm (SI), and 3.2 mm (AP). No marker migration was observed in the cohort. Conclusion: Clinically feasible, rapid, and reliable tools such as the electromagnetic transponder detection system for pretreatment target localization

  10. Hypervelocity Impact (HVI). Volume 8; Tile Small Targets A-1, Ag-1, B-1, and Bg-1

    NASA Technical Reports Server (NTRS)

    Gorman, Michael R.; Ziola, Steven M.

    2007-01-01

    During 2003 and 2004, the Johnson Space Center's White Sands Testing Facility in Las Cruces, New Mexico conducted hypervelocity impact tests on the space shuttle wing leading edge. Hypervelocity impact tests were conducted to determine if Micro-Meteoroid/Orbital Debris impacts could be reliably detected and located using simple passive ultrasonic methods. The objective of Targets A-1, Ag-1, B-1, and Bg-1 was to study hypervelocity impacts on the reinforced Shuttle Heat Shield Tiles of the Wing. Impact damage was detected using lightweight, low power instrumentation capable of being used in flight.

  11. A novel, volumizing cosmetic formulation significantly improves the appearance of target Glabellar lines, nasolabial folds, and crow's feet in a double-blind, vehicle-controlled clinical trial.

    PubMed

    Farris, Patricia K; Edison, Brenda L; Weinkauf, Ronni L; Green, Barbara A

    2014-01-01

    Facial lines and wrinkles are caused by many factors including constant exposure to external elements, such as UV rays, as well as the dynamic nature of facial expression. Many cosmetic products and procedures provide global improvement to aging skin, whereas injectable therapies are frequently utilized to diminish specific, target wrinkles. Despite their broad availability, some patients are unwilling to undergo injectables and would benefit from an effective topical option. A noninvasive option to volumize target wrinkle areas could also extend benefits of commonly used cosmetic anti-aging products. To this end, a two-step formulation containing the novel, cosmetic anti-aging ingredient, N-acetyl tyrosinamide, was developed for use on targeted wrinkle areas. The tolerability and efficacy of the serum plus cream were tested for 16 weeks in women with moderate facial photodamage on predetermined wrinkle areas (glabellar lines, nasolabial folds, under eye lines, and lateral canthal (crow's feet) wrinkles) in a single-center, randomized, double-blind, vehicle-controlled, clinical trial. Seventy women (47 Active group, 23 Vehicle group) completed the study. Digital photography, clinical grading, ultrasound and self-assessment scores confirmed improvement to wrinkle areas. The topical cosmetic formulation was statistically superior (P<0.05) to its vehicle in visually improving nasolabial folds, glabellar lines, crow's feet, and under eye wrinkles and in reducing pinch recoil time. Both the test formulation and its vehicle were tolerated well. The novel, two-step cosmetic formulation reduced the appearance of wrinkles and increased skin elasticity thus providing an effective anti-aging option for target wrinkle areas. This study suggests that in addition to its use as monotherapy for reducing targeted lines and wrinkles this cosmetic formulation may be also serve as an adjuvant to injectable therapies.

  12. Analysis of Lung Tumor Motion in a Large Sample: Patterns and Factors Influencing Precise Delineation of Internal Target Volume.

    PubMed

    Knybel, Lukas; Cvek, Jakub; Molenda, Lukas; Stieberova, Natalie; Feltl, David

    2016-11-15

    To evaluate lung tumor motion during respiration and to describe factors affecting the range and variability of motion in patients treated with stereotactic ablative radiation therapy. Log file analysis from online respiratory tumor tracking was performed in 145 patients. Geometric tumor location in the lungs, tumor volume and origin (primary or metastatic), sex, and tumor motion amplitudes in the superior-inferior (SI), latero-lateral (LL), and anterior-posterior (AP) directions were recorded. Tumor motion variability during treatment was described using intrafraction/interfraction amplitude variability and tumor motion baseline changes. Tumor movement dependent on the tumor volume, position and origin, and sex were evaluated using statistical regression and correlation analysis. After analysis of >500 hours of data, the highest rates of motion amplitudes, intrafraction/interfraction variation, and tumor baseline changes were in the SI direction (6.0 ± 2.2 mm, 2.2 ± 1.8 mm, 1.1 ± 0.9 mm, and -0.1 ± 2.6 mm). The mean motion amplitudes in the lower/upper geometric halves of the lungs were significantly different (P<.001). Motion amplitudes >15 mm were observed only in the lower geometric quarter of the lungs. Higher tumor motion amplitudes generated higher intrafraction variations (R=.86, P<.001). Interfraction variations and baseline changes >3 mm indicated tumors contacting mediastinal structures or parietal pleura. On univariate analysis, neither sex nor tumor origin (primary vs metastatic) was an independent predictive factor of different movement patterns. Metastatic lesions in women, but not men, showed significantly higher mean amplitudes (P=.03) and variability (primary, 2.7 mm; metastatic, 4.9 mm; P=.002) than primary tumors. Online tracking showed significant irregularities in lung tumor movement during respiration. Motion amplitude was significantly lower in upper lobe tumors; higher interfraction amplitude variability indicated

  13. Therapeutic analysis of high-dose-rate {sup 192}Ir vaginal cuff brachytherapy for endometrial cancer using a cylindrical target volume model and varied cancer cell distributions

    SciTech Connect

    Zhang, Hualin Donnelly, Eric D.; Strauss, Jonathan B.; Qi, Yujin

    2016-01-15

    Purpose: To evaluate high-dose-rate (HDR) vaginal cuff brachytherapy (VCBT) in the treatment of endometrial cancer in a cylindrical target volume with either a varied or a constant cancer cell distributions using the linear quadratic (LQ) model. Methods: A Monte Carlo (MC) technique was used to calculate the 3D dose distribution of HDR VCBT over a variety of cylinder diameters and treatment lengths. A treatment planning system (TPS) was used to make plans for the various cylinder diameters, treatment lengths, and prescriptions using the clinical protocol. The dwell times obtained from the TPS were fed into MC. The LQ model was used to evaluate the therapeutic outcome of two brachytherapy regimens prescribed either at 0.5 cm depth (5.5 Gy × 4 fractions) or at the vaginal mucosal surface (8.8 Gy × 4 fractions) for the treatment of endometrial cancer. An experimentally determined endometrial cancer cell distribution, which showed a varied and resembled a half-Gaussian distribution, was used in radiobiology modeling. The equivalent uniform dose (EUD) to cancer cells was calculated for each treatment scenario. The therapeutic ratio (TR) was defined by comparing VCBT with a uniform dose radiotherapy plan in term of normal cell survival at the same level of cancer cell killing. Calculations of clinical impact were run twice assuming two different types of cancer cell density distributions in the cylindrical target volume: (1) a half-Gaussian or (2) a uniform distribution. Results: EUDs were weakly dependent on cylinder size, treatment length, and the prescription depth, but strongly dependent on the cancer cell distribution. TRs were strongly dependent on the cylinder size, treatment length, types of the cancer cell distributions, and the sensitivity of normal tissue. With a half-Gaussian distribution of cancer cells which populated at the vaginal mucosa the most, the EUDs were between 6.9 Gy × 4 and 7.8 Gy × 4, the TRs were in the range from (5.0){sup 4} to (13

  14. Therapeutic analysis of high-dose-rate (192)Ir vaginal cuff brachytherapy for endometrial cancer using a cylindrical target volume model and varied cancer cell distributions.

    PubMed

    Zhang, Hualin; Donnelly, Eric D; Strauss, Jonathan B; Qi, Yujin

    2016-01-01

    To evaluate high-dose-rate (HDR) vaginal cuff brachytherapy (VCBT) in the treatment of endometrial cancer in a cylindrical target volume with either a varied or a constant cancer cell distributions using the linear quadratic (LQ) model. A Monte Carlo (MC) technique was used to calculate the 3D dose distribution of HDR VCBT over a variety of cylinder diameters and treatment lengths. A treatment planning system (TPS) was used to make plans for the various cylinder diameters, treatment lengths, and prescriptions using the clinical protocol. The dwell times obtained from the TPS were fed into MC. The LQ model was used to evaluate the therapeutic outcome of two brachytherapy regimens prescribed either at 0.5 cm depth (5.5 Gy × 4 fractions) or at the vaginal mucosal surface (8.8 Gy × 4 fractions) for the treatment of endometrial cancer. An experimentally determined endometrial cancer cell distribution, which showed a varied and resembled a half-Gaussian distribution, was used in radiobiology modeling. The equivalent uniform dose (EUD) to cancer cells was calculated for each treatment scenario. The therapeutic ratio (TR) was defined by comparing VCBT with a uniform dose radiotherapy plan in term of normal cell survival at the same level of cancer cell killing. Calculations of clinical impact were run twice assuming two different types of cancer cell density distributions in the cylindrical target volume: (1) a half-Gaussian or (2) a uniform distribution. EUDs were weakly dependent on cylinder size, treatment length, and the prescription depth, but strongly dependent on the cancer cell distribution. TRs were strongly dependent on the cylinder size, treatment length, types of the cancer cell distributions, and the sensitivity of normal tissue. With a half-Gaussian distribution of cancer cells which populated at the vaginal mucosa the most, the EUDs were between 6.9 Gy × 4 and 7.8 Gy × 4, the TRs were in the range from (5.0)(4) to (13.4)(4) for the radiosensitive normal

  15. Therapeutic analysis of high-dose-rate 192Ir vaginal cuff brachytherapy for endometrial cancer using a cylindrical target volume model and varied cancer cell distributions

    PubMed Central

    Zhang, Hualin; Donnelly, Eric D.; Strauss, Jonathan B.; Qi, Yujin

    2016-01-01

    Purpose: To evaluate high-dose-rate (HDR) vaginal cuff brachytherapy (VCBT) in the treatment of endometrial cancer in a cylindrical target volume with either a varied or a constant cancer cell distributions using the linear quadratic (LQ) model. Methods: A Monte Carlo (MC) technique was used to calculate the 3D dose distribution of HDR VCBT over a variety of cylinder diameters and treatment lengths. A treatment planning system (TPS) was used to make plans for the various cylinder diameters, treatment lengths, and prescriptions using the clinical protocol. The dwell times obtained from the TPS were fed into MC. The LQ model was used to evaluate the therapeutic outcome of two brachytherapy regimens prescribed either at 0.5 cm depth (5.5 Gy × 4 fractions) or at the vaginal mucosal surface (8.8 Gy × 4 fractions) for the treatment of endometrial cancer. An experimentally determined endometrial cancer cell distribution, which showed a varied and resembled a half-Gaussian distribution, was used in radiobiology modeling. The equivalent uniform dose (EUD) to cancer cells was calculated for each treatment scenario. The therapeutic ratio (TR) was defined by comparing VCBT with a uniform dose radiotherapy plan in term of normal cell survival at the same level of cancer cell killing. Calculations of clinical impact were run twice assuming two different types of cancer cell density distributions in the cylindrical target volume: (1) a half-Gaussian or (2) a uniform distribution. Results: EUDs were weakly dependent on cylinder size, treatment length, and the prescription depth, but strongly dependent on the cancer cell distribution. TRs were strongly dependent on the cylinder size, treatment length, types of the cancer cell distributions, and the sensitivity of normal tissue. With a half-Gaussian distribution of cancer cells which populated at the vaginal mucosa the most, the EUDs were between 6.9 Gy × 4 and 7.8 Gy × 4, the TRs were in the range from (5.0)4 to (13.4)4 for the

  16. Coregistration of Prechemotherapy PET-CT for Planning Pediatric Hodgkin's Disease Radiotherapy Significantly Diminishes Interobserver Variability of Clinical Target Volume Definition

    SciTech Connect

    Metwally, Hussein; Courbon, Frederic; David, Isabelle; Filleron, Thomas; Blouet, Aurelien; Rives, Michel; Izar, Francoise; Zerdoud, Slimane; Plat, Genevieve; Vial, Julie; Robert, Alain; Laprie, Anne

    2011-07-01

    Purpose: To assess the interobserver variability in clinical target volume (CTV) definitions when using registered {sup 18}F-labeled deoxyglucose positron emission tomography (FDG-PET-CT) versus side-by-side image sets in pediatric Hodgkin's disease (HD). Methods and Materials: Prechemotherapy FDG-PET-CT scans performed in the treatment position were acquired from 20 children (median age, 14 years old) with HD (stages 2A to 4B) and registered with postchemotherapy planning CT scans. The patients had a median age of 14 years and stages of disease ranging between 2A and 4B. Image sets were coregistered using a semiautomatic coregistration system. The biological target volume was defined on all the coregistered images as a guide to defining the initial site of involvement and to avoid false-positive or negative results. Five radiation oncologists independently defined the CTV for all 20 patients: once using separate FDG-PET-CT images as a guide (not registered) to define CTVa and once using the registered FDG-PET-CT data to define CTVb. The total volumes were compared, as well as their coefficients of variation (COV). To assess the interobserver variability, the percentages of intersection between contours drawn by all observers for each patient were calculated for CTVa and for CTVb. Results: The registration of a prechemotherapy FDG-PET-CT scan caused a change in the CTV for all patients. Comparing CTVa with CTVb showed that the mean CTVb increased in 14 patients (range, 0.61%-101.96%) and decreased in 6 patients (range, 2.97%-37.26%). The COV for CTVb significantly decreased for each patient; the mean COVs for CTVa and CTVb were 45% (21%-65%) and 32% (13%-57%), respectively (p = 0.0004). The percentage of intersection among all CTVbs for the five observers increased significantly by 89.77% (1.99%-256.41%) compared to that of CTVa (p = 0.0001). Conclusions: High observer variability can occur during CT-based definition of CTVs for children diagnosed with HD

  17. Comparison and Consensus Guidelines for Delineation of Clinical Target Volume for CT- and MR-Based Brachytherapy in Locally Advanced Cervical Cancer

    SciTech Connect

    Viswanathan, Akila N.; Gaffney, David K.; Beriwal, Sushil; Bhatia, Sudershan K.; Lee Burnett, Omer; D'Souza, David P.; Patil, Nikhilesh; Haddock, Michael G.; Jhingran, Anuja; Jones, Ellen L.; Kunos, Charles A.; Lee, Larissa J.; Mayr, Nina A.; Petersen, Ivy; Petric, Primoz; Portelance, Lorraine; Small, William; Strauss, Jonathan B.; and others

    2014-10-01

    Objective: To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3-Tesla (3-T) magnetic resonance (MR) image-based cervical-cancer brachytherapy. Methods and Materials: Twenty-three experts in gynecologic radiation oncology contoured the same 3 cervical cancer brachytherapy cases: 1 stage IIB near-complete response (CR) case with a tandem and ovoid, 1 stage IIB partial response (PR) case with tandem and ovoid with needles, and 1 stage IB2 CR case with a tandem and ring applicator. The CT contours were completed before the MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with κ statistics as a measure of agreement between participants. The conformity index was calculated for each of the 6 data sets. Dice coefficients were generated to compare the CT and MR contours of the same case. Results: For all 3 cases, the mean tumor volume was smaller on MR than on CT (P<.001). The κ and conformity index estimates were slightly higher for CT, indicating a higher level of agreement on CT. The Dice coefficients were 89% for the stage IB2 case with a CR, 74% for the stage IIB case with a PR, and 57% for the stage IIB case with a CR. Conclusion: In a comparison of MR-contoured with CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast medium visible on the images at the time of brachytherapy. MR at the time of brachytherapy may be of greatest benefit in patients with large tumors with parametrial extension that have a partial or complete response to external beam. On the basis of these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at (http://www.nrgoncology.org/Resources/ContouringAtlases/GYNCervicalBrachytherapy.aspx)

  18. Magnetic Resonance Imaging-Based Target Volume Delineation in Radiation Therapy Treatment Planning for Brain Tumors Using Localized Region-Based Active Contour

    SciTech Connect

    Aslian, Hossein; Sadeghi, Mahdi; Mahdavi, Seied Rabie; Babapour Mofrad, Farshid; Astarakee, Mahdi; Khaledi, Navid; Fadavi, Pedram

    2013-09-01

    Purpose: To evaluate the clinical application of a robust semiautomatic image segmentation method to determine the brain target volumes in radiation therapy treatment planning. Methods and Materials: A local robust region-based algorithm was used on MRI brain images to study the clinical target volume (CTV) of several patients. First, 3 oncologists delineated CTVs of 10 patients manually, and the process time for each patient was calculated. The averages of the oncologists’ contours were evaluated and considered as reference contours. Then, to determine the CTV through the semiautomatic method, a fourth oncologist who was blind to all manual contours selected 4-8 points around the edema and defined the initial contour. The time to obtain the final contour was calculated again for each patient. Manual and semiautomatic segmentation were compared using 3 different metric criteria: Dice coefficient, Hausdorff distance, and mean absolute distance. A comparison also was performed between volumes obtained from semiautomatic and manual methods. Results: Manual delineation processing time of tumors for each patient was dependent on its size and complexity and had a mean (±SD) of 12.33 ± 2.47 minutes, whereas it was 3.254 ± 1.7507 minutes for the semiautomatic method. Means of Dice coefficient, Hausdorff distance, and mean absolute distance between manual contours were 0.84 ± 0.02, 2.05 ± 0.66 cm, and 0.78 ± 0.15 cm, and they were 0.82 ± 0.03, 1.91 ± 0.65 cm, and 0.7 ± 0.22 cm between manual and semiautomatic contours, respectively. Moreover, the mean volume ratio (=semiautomatic/manual) calculated for all samples was 0.87. Conclusions: Given the deformability of this method, the results showed reasonable accuracy and similarity to the results of manual contouring by the oncologists. This study shows that the localized region-based algorithms can have great ability in determining the CTV and can be appropriate alternatives for manual approaches in brain cancer.

  19. Coregistration of prechemotherapy PET-CT for planning pediatric Hodgkin's disease radiotherapy significantly diminishes interobserver variability of clinical target volume definition.

    PubMed

    Metwally, Hussein; Courbon, Frédéric; David, Isabelle; Filleron, Thomas; Blouet, Aurélien; Rives, Michel; Izar, Françoise; Zerdoud, Slimane; Plat, Geneviève; Vial, Julie; Robert, Alain; Laprie, Anne

    2011-07-01

    To assess the interobserver variability in clinical target volume (CTV) definitions when using registered (18)F-labeled deoxyglucose positron emission tomography (FDG-PET-CT) versus side-by-side image sets in pediatric Hodgkin's disease (HD). Prechemotherapy FDG-PET-CT scans performed in the treatment position were acquired from 20 children (median age, 14 years old) with HD (stages 2A to 4B) and registered with postchemotherapy planning CT scans. The patients had a median age of 14 years and stages of disease ranging between 2A and 4B. Image sets were coregistered using a semiautomatic coregistration system. The biological target volume was defined on all the coregistered images as a guide to defining the initial site of involvement and to avoid false-positive or negative results. Five radiation oncologists independently defined the CTV for all 20 patients: once using separate FDG-PET-CT images as a guide (not registered) to define CTVa and once using the registered FDG-PET-CT data to define CTVb. The total volumes were compared, as well as their coefficients of variation (COV). To assess the interobserver variability, the percentages of intersection between contours drawn by all observers for each patient were calculated for CTVa and for CTVb. The registration of a prechemotherapy FDG-PET-CT scan caused a change in the CTV for all patients. Comparing CTVa with CTVb showed that the mean CTVb increased in 14 patients (range, 0.61%-101.96%) and decreased in 6 patients (range, 2.97%-37.26%). The COV for CTVb significantly decreased for each patient; the mean COVs for CTVa and CTVb were 45% (21%-65%) and 32% (13%-57%), respectively (p = 0.0004). The percentage of intersection among all CTVbs for the five observers increased significantly by 89.77% (1.99%-256.41%) compared to that of CTVa (p = 0.0001). High observer variability can occur during CT-based definition of CTVs for children diagnosed with HD. Registration of FDG-PET and planning CT images resulted in

  20. Simulation of tissue activity curves of 64Cu-ATSM for sub-target volume delineation in radiotherapy

    NASA Astrophysics Data System (ADS)

    Dalah, E.; Bradley, D.; Nisbet, A.

    2010-02-01

    There is much interest in positron emission tomography (PET) for measurements of regional tracer concentration in hypoxic tumour-bearing tissue, focusing on the need for accurate radiotherapy treatment planning. Generally, relevant data are taken over multiple time frames in the form of tissue activity curves (TACs), thus providing an indication of vasculature structure and geometry. This is a potential key in providing information on cellular perfusion and limited diffusion. A number of theoretical studies have attempted to describe tracer uptake in tissue cells in an effort to understand such complicated behaviour of cellular uptake and the mechanism of washout. More recently, a novel computerized reaction diffusion equation method was developed by Kelly and Brady (2006 A model to simulate tumour oxygenation and dynamic [18F]-FMISO PET data Phys. Med. Biol. 51 5859-73), where they managed to simulate the realistic dynamic TACs of 18F-FMISO. The model was developed over a multi-step process. Here we present a refinement to the work of Kelly and Brady, such that the model allows simulation of a realistic tissue activity curve (TAC) of any hypoxia selective PET tracer, in a single step process. In this work we show particular interest in simulating the TAC of perhaps the most promising hypoxia selective tracer, 64Cu-ATSM. In addition, we demonstrate its potential role in tumour sub-volume delineation for radiotherapy treatment planning. Simulation results have demonstrated the significant high contrast of imaging using ATSM, with a tumour to blood ratio ranging from 2.24 to 4.1.

  1. SU-E-T-389: Effect of Interfractional Shoulder Motion On Low Neck Nodal Targets for Patients Treated Using Volume Modulated Arc Therapy (VMAT)

    SciTech Connect

    Casey, K; Wong, P; Tung, S

    2014-06-01

    Purpose: To quantify the dosimetric impact of interfractional shoulder motion on targets in the low neck for head and neck patients treated with volume modulated arc therapy (VMAT). Methods: Three patients with head and neck cancer were selected. All three required treatment to nodal regions in the low neck in addition to the primary tumor. The patients were immobilized during simulation and treatment with a custom thermoplastic mask covering the head and shoulders. One VMAT plan was created for each patient utilizing two full 360° arcs. A second plan was created consisting of two superior VMAT arcs matched to an inferior static AP supraclavicular field. A CT-on-rails alignment verification was performed weekly during each patient's treatment course. The weekly CT images were registered to the simulation CT and the target contours were deformed and applied to the weekly CT. The two VMAT plans were copied to the weekly CT datasets and recalculated to obtain the dose to the low neck contours. Results: The average observed shoulder position shift in any single dimension relative to simulation was 2.5 mm. The maximum shoulder shift observed in a single dimension was 25.7 mm. Low neck target mean doses, normalized to simulation and averaged across all weekly recalculations were 0.996, 0.991, and 1.033 (Full VMAT plan) and 0.986, 0.995, and 0.990 (Half-Beam VMAT plan) for the three patients, respectively. The maximum observed deviation in target mean dose for any individual weekly recalculation was 6.5%, occurring with the Full VMAT plan for Patient 3. Conclusion: Interfractional variation in dose to low neck nodal regions was quantified for three head and neck patients treated with VMAT. Mean dose was 3.3% higher than planned for one patient using a Full VMAT plan. A Half-Beam technique is likely a safer choice when treating the supraclavicular region with VMAT.

  2. Beam-specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors.

    PubMed

    Lin, Liyong; Kang, Minglei; Huang, Sheng; Mayer, Rulon; Thomas, Andrew; Solberg, Timothy D; McDonough, James E; Simone, Charles B

    2015-11-08

    The purpose of this study is to determine whether organ sparing and target coverage can be simultaneously maintained for pencil beam scanning (PBS) proton therapy treatment of thoracic tumors in the presence of motion, stopping power uncertainties, and patient setup variations. Ten consecutive patients that were previously treated with proton therapy to 66.6/1.8 Gy (RBE) using double scattering (DS) were replanned with PBS. Minimum and maximum intensity images from 4D CT were used to introduce flexible smearing in the determination of the beam specific PTV (BSPTV). Datasets from eight 4D CT phases, using ± 3% uncertainty in stopping power and ± 3 mm uncertainty in patient setup in each direction, were used to create 8 × 12 × 10 = 960 PBS plans for the evaluation of 10 patients. Plans were normalized to provide identical coverage between DS and PBS. The average lung V20, V5, and mean doses were reduced from 29.0%, 35.0%, and 16.4 Gy with DS to 24.6%, 30.6%, and 14.1 Gy with PBS, respectively. The average heart V30 and V45 were reduced from 10.4% and 7.5% in DS to 8.1% and 5.4% for PBS, respectively. Furthermore, the maximum spinal cord, esophagus, and heart doses were decreased from 37.1 Gy, 71.7 Gy, and 69.2 Gy with DS to 31.3 Gy, 67.9 Gy, and 64.6 Gy with PBS. The conformity index (CI), homogeneity index (HI), and global maximal dose were improved from 3.2, 0.08, 77.4 Gy with DS to 2.8, 0.04, and 72.1 Gy with PBS. All differences are statistically significant, with p-values <0.05, with the exception of the heart V45 (p = 0.146). PBS with BSPTV achieves better organ sparing and improves target coverage using a repainting method for the treatment of thoracic tumors. Incorporating motion-related uncertainties is essential.

  3. Beam-specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors.

    PubMed

    Lin, Liyong; Kang, Minglei; Huang, Sheng; Mayer, Rulon; Thomas, Andrew; Solberg, Timothy D; McDonough, James E; Simone, Charles B

    2015-11-01

    The purpose of this study is to determine whether organ sparing and target coverage can be simultaneously maintained for pencil beam scanning (PBS) proton therapy treatment of thoracic tumors in the presence of motion, stopping power uncertainties, and patient setup variations. Ten consecutive patients that were previously treated with proton therapy to 66.6/1.8 Gy (RBE) using double scattering (DS) were replanned with PBS. Minimum and maximum intensity images from 4D CT were used to introduce flexible smearing in the determination of the beam specific PTV (BSPTV). Datasets from eight 4D CT phases, using ±3% uncertainty in stopping power and ±3 mm uncertainty in patient setup in each direction, were used to create 8×12×10=960 PBS plans for the evaluation of 10 patients. Plans were normalized to provide identical coverage between DS and PBS. The average lung V20, V5, and mean doses were reduced from 29.0%, 35.0%, and 16.4 Gy with DS to 24.6%, 30.6%, and 14.1 Gy with PBS, respectively. The average heart V30 and V45 were reduced from 10.4% and 7.5% in DS to 8.1% and 5.4% for PBS, respectively. Furthermore, the maximum spinal cord, esophagus, and heart doses were decreased from 37.1 Gy, 71.7 Gy, and 69.2 Gy with DS to 31.3 Gy, 67.9 Gy, and 64.6 Gy with PBS. The conformity index (CI), homogeneity index (HI), and global maximal dose were improved from 3.2, 0.08, 77.4 Gy with DS to 2.8, 0.04, and 72.1 Gy with PBS. All differences are statistically significant, with p-values <0.05, with the exception of the heart V45 (p=0.146). PBS with BSPTV achieves better organ sparing and improves target coverage using a repainting method for the treatment of thoracic tumors. Incorporating motion-related uncertainties is essential. PACS number: 87.55.D.

  4. Segmentation of biological target volumes on multi-tracer PET images based on information fusion for achieving dose painting in radiotherapy.

    PubMed

    Lelandais, Benoît; Gardin, Isabelle; Mouchard, Laurent; Vera, Pierre; Ruan, Su

    2012-01-01

    Medical imaging plays an important role in radiotherapy. Dose painting consists in the application of a nonuniform dose prescription on a tumoral region, and is based on an efficient segmentation of biological target volumes (BTV). It is derived from PET images, that highlight tumoral regions of enhanced glucose metabolism (FDG), cell proliferation (FLT) and hypoxia (FMiso). In this paper, a framework based on Belief Function Theory is proposed for BTV segmentation and for creating 3D parametric images for dose painting. We propose to take advantage of neighboring voxels for BTV segmentation, and also multi-tracer PET images using information fusion to create parametric images. The performances of BTV segmentation was evaluated on an anthropomorphic phantom and compared with two other methods. Quantitative results show the good performances of our method. It has been applied to data of five patients suffering from lung cancer. Parametric images show promising results by highlighting areas where a high frequency or dose escalation could be planned.

  5. Explaining clinical effects of deep brain stimulation through simplified target-specific modeling of the volume of activated tissue.

    PubMed

    Mädler, B; Coenen, V A

    2012-06-01

    Although progress has been made in understanding the optimal anatomic structures as target areas for DBS, little effort has been put into modeling and predicting electromagnetic field properties of activated DBS electrodes and understanding their interactions with the adjacent tissue. Currently, DBS is performed with the patient awake to assess the effectiveness and the side effect spectrum of stimulation. This study was designed to create a robust and rather simple numeric and visual tool that provides sufficient and practical relevant information to visualize the patient's individual VAT. Multivariate polynomial fitting of previously obtained data from a finite-element model, based on a similar DBS system, was used. The model estimates VAT as a first-approximation sphere around the active DBS contact, using stimulation voltages and individual tissue-electrode impedances. Validation uses data from 2 patients with PD by MR imaging, DTI, fiber tractography, and postoperative CT data. Our model can predict VAT for impedances between 500 and 2000 Ω with stimulation voltages up to 10 V. It is based on assumptions for monopolar DBS. Evaluation of 2 DBS cases showed a convincing correspondence between predicted VAT and neurologic (side) effects (internal capsule activation). Stimulation effects during DBS can be readily explained with this simple VAT model. Its implementation in daily clinical routine might help in understanding the types of tissues activated during DBS. This technique might have the potential to facilitate DBS implantations with the patient under general anesthesia while yielding acceptable clinical effectiveness.

  6. Adenocarcinoma of the Esophagogastric Junction: The Pattern of Metastatic Lymph Node Dissemination as a Rationale for Elective Lymphatic Target Volume Definition

    SciTech Connect

    Meier, Iris; Merkel, Susanne; Papadopoulos, Thomas; Sauer, Rolf; Hohenberger, Werner; Brunner, Thomas B.

    2008-04-01

    Purpose: Regional nodal metastasis after neoadjuvant chemoradiation of adenocarcinoma of the esophagogastric junction (AEG) predicts survival. We aimed to clarify the lymph node (LN) distribution of AEG according to location of the tumor mass and invasion of neighboring areas for the selection of radiotherapy planning target volume (PTV) margins. Methods and Materials: Patterns of regional spread were analyzed in pathology reports of 326 patients patients with AEG who had undergone primary resection, with {>=}15 lymph nodes examined. Tumors were classified into AEG types based on endoscopy and pathology reports. Fisher's exact test was used to compare nodal disease and tumor characteristics. Pulmonary dose-volume histograms were tested in 8 patients. Results: Nodes were positive in 81% of T2 to T4 tumors. Type of AEG, tumor size, lymphovascular invasion, and grading significantly influenced nodal distribution. We found that marked esophageal invasion of AEG II/III significantly correlated with paraesophageal nodal disease, and T3 to T4 AEG II/III had a significant rate of splenic hilum/artery nodes. Middle and lower paraesophageal nodes should be treated in T2 to T4 AEG I and AEG II with {>=}15 mm involvement above the Z-line, and T3 to T4 AEG II. The splenic hilum and artery nodes can be spared in T2 AEG tumors, especially Type I tumors. The influence of paraesophageal nodal treatment on the risk of postoperative pulmonary complications can be estimated from dose-volume histograms. Conclusions: Accurate pretherapeutic staging predicts the risk of subclinical nodal disease and should be used to select the appropriate radiotherapeutic PTV. Careful selection of the PTV can be used to maximize the therapeutic window in multimodal therapy for AEG.

  7. Development of RTOG Consensus Guidelines for the Definition of the Clinical Target Volume for Postoperative Conformal Radiation Therapy for Prostate Cancer

    SciTech Connect

    Michalski, Jeff M.; Lawton, Colleen; El Naqa, Issam; Ritter, Mark; O'Meara, Elizabeth C.; Seider, Michael J.; Lee, W. Robert; Rosenthal, Seth A.; Pisansky, Thomas; Catton, Charles; Valicenti, Richard K.; Zietman, Anthony L.; Bosch, Walter R.; Sandler, Howard; Buyyounouski, Mark K.; Menard, Cynthia

    2010-02-01

    Purpose: To define a prostate fossa clinical target volume (PF-CTV) for Radiation Therapy Oncology Group (RTOG) trials using postoperative radiotherapy for prostate cancer. Methods and Materials: An RTOG-sponsored meeting was held to define an appropriate PF-CTV after radical prostatectomy. Data were presented describing radiographic failure patterns after surgery. Target volumes used in previous trials were reviewed. Using contours independently submitted by 13 radiation oncologists, a statistical imputation method derived a preliminary 'consensus' PF-CTV. Results: Starting from the model-derived CTV, consensus was reached for a CT image-based PF-CTV. The PF-CTV should extend superiorly from the level of the caudal vas deferens remnant to >8-12 mm inferior to vesicourethral anastomosis (VUA). Below the superior border of the pubic symphysis, the anterior border extends to the posterior aspect of the pubis and posteriorly to the rectum, where it may be concave at the level of the VUA. At this level, the lateral border extends to the levator ani. Above the pubic symphysis, the anterior border should encompass the posterior 1-2 cm of the bladder wall; posteriorly, it is bounded by the mesorectal fascia. At this level, the lateral border is the sacrorectogenitopubic fascia. Seminal vesicle remnants, if present, should be included in the CTV if there is pathologic evidence of their involvement. Conclusions: Consensus on postoperative PF-CTV for RT after prostatectomy was reached and is available as a CT image atlas on the RTOG website. This will allow uniformity in defining PF-CTV for clinical trials that include postprostatectomy RT.

  8. A Prospective Pathologic Study to Define the Clinical Target Volume for Partial Breast Radiation Therapy in Women With Early Breast Cancer

    SciTech Connect

    Nguyen, Brandon T.; Deb, Siddhartha; Fox, Stephen; Hill, Prudence; Collins, Marnie; Chua, Boon H.

    2012-12-01

    Purpose: To determine an appropriate clinical target volume for partial breast radiation therapy (PBRT) based on the spatial distribution of residual invasive and in situ carcinoma after wide local excision (WLE) for early breast cancer or ductal carcinoma in situ (DCIS). Methods and Materials: We performed a prospective pathologic study of women potentially eligible for PBRT who had re-excision and/or completion mastectomy after WLE for early breast cancer or DCIS. A pathologic assessment protocol was used to determine the maximum radial extension (MRE) of residual carcinoma from the margin of the initial surgical cavity. Women were stratified by the closest initial radial margin width: negative (>1 mm), close (>0 mm and {<=}1 mm), or involved. Results: The study population was composed of 133 women with a median age of 59 years (range, 27-82 years) and the following stage groups: 0 (13.5%), I (40.6%), II (38.3%), and III (7.5%). The histologic subtypes of the primary tumor were invasive ductal carcinoma (74.4%), invasive lobular carcinoma (12.0%), and DCIS alone (13.5%). Residual carcinoma was present in the re-excision and completion mastectomy specimens in 55.4%, 14.3%, and 7.2% of women with an involved, close, and negative margin, respectively. In the 77 women with a noninvolved radial margin, the MRE of residual disease, if present, was {<=}10 mm in 97.4% (95% confidence interval 91.6-99.5) of cases. Larger MRE measurements were significantly associated with an involved margin (P<.001), tumor size >30 mm (P=.03), premenopausal status (P=.03), and negative progesterone receptor status (P=.05). Conclusions: A clinical target volume margin of 10 mm would encompass microscopic residual disease in >90% of women potentially eligible for PBRT after WLE with noninvolved resection margins.

  9. Improved target volume definition for fractionated stereotactic radiotherapy in patients with intracranial meningiomas by correlation of CT, MRI, and [{sup 68}Ga]-DOTATOC-PET

    SciTech Connect

    Milker-Zabel, Stefanie . E-mail: stefanie_milker-zabel@med.uni-heidelberg.de; Zabel-du Bois, Angelika; Henze, Marcus; Huber, Peter; Schulz-Ertner, Daniela; Hoess, Angelika; Haberkorn, Uwe; Debus, Juergen

    2006-05-01

    Purpose: To evaluate the influence of {sup 68}-Ga-labeled DOTA ( )-D-Phe ({sup 1})-Tyr ({sup 3})-Octreotide positron emission tomography ([{sup 68}Ga]-DOTATOC-PET) for target definition for fractionated stereotactic radiotherapy (FSRT) as a complementary modality to computed tomography (CT) and magnetic resonance imaging (MRI). Because meningiomas show a high expression of somatostatin receptor subtype 2, somatostatin analogs such as DOTATOC offer the possibility of receptor-targeted imaging. Patients and Methods: Twenty-six patients received stereotactic CT, MRI, and [{sup 68}Ga]-DOTATOC-PET as part of their treatment planning. Histology was: World Health Organization (WHO) Grade 1 61.5%, WHO Grade 2 7.7%, WHO Grade 3 3.9%, and undetermined 26.9%. Six patients received radiotherapy as primary treatment, 2 after subtotal resection; 17 patients were treated for recurrent disease. Dynamic PET scans were acquired before radiotherapy over 60 min after intravenous injection of 156 {+-} 29 MBq [{sup 68}Ga]-DOTATOC. These PET images were imported in the planning software for FSRT. Planning target volume (PTV)-I outlined on CT and contrast-enhanced MRI was compared with PTV-II outlined on PET. PTV-III was defined with CT, MRI, and PET and was actually used for radiotherapy treatment. Results: PTV-III was smaller than PTV-I in 9 patients, the same size in 7 patients, and larger in 10 patients. Median PTV-I was 49.6 cc, median PTV-III was 57.2 cc. In all patients [{sup 68}Ga]-DOTATOC-PET delivered additional information concerning tumor extension. PTV-III was significantly modified based on DOTATOC-PET data in 19 patients. In 1 patient no tumor was exactly identified on CT/MRI but was visible on PET. Conclusion: These data demonstrate that [{sup 68}Ga]-DOTATOC-PET improves target definition for FSRT in patients with intracranial meningiomas. Radiation targeting with fused DOTATOC-PET, CT, and MRI resulted in significant alterations in target definition in 73%.

  10. A Prospective Evaluation of Staging and Target Volume Definition of Lymph Nodes by {sup 18}FDG PET/CT in Patients With Squamous Cell Carcinoma of Thoracic Esophagus

    SciTech Connect

    Yu Wen; Fu Xiaolong; Zhang Yingjian; Xiang Jiaqing; Shen Lei; Chang, Joe Y.

    2011-12-01

    Purpose: To determine an optimal standardized uptake value (SUV) threshold for detecting lymph node (LN) metastases in esophageal cancer using {sup 18}F-Fluorodeoxyglucose positron emission tomography/computer tomography ({sup 18}FDG PET/CT) and to define the resulting nodal target volume, using histopathology as a 'gold standard.' Methods: Sixteen patients with esophageal squamous cell carcinoma who underwent radical esophagectomy and three-field LN dissection after {sup 18}FDG PET/CT and CT scans were enrolled into this study. Locations of LN groups were recorded according to a uniform LN map. Diagnostic performance of different SUV thresholds was assessed by receiver operating characteristic analysis. The optimal cutoff SUV was determined by plotting the false-negative rate (FNR) and false-positive rate (FPR), the sum of both error rates (FNR+FPR), and accuracy against a hypothetical SUV threshold. For each patient, nodal gross tumor volumes (GTVNs) were generated with CT alone (GTVNCT), PET/CT (GTVNPET), and pathologic data (GTVNpath). GTVNCT or GTVNPET was compared with GTVNpath by means of a conformity index (CI), which is the intersection of the two GTVNs divided by the sum of them minus the intersection, e.g., CI{sub CT} and {sub path} = GTVN{sub CT} and {sub path}/(GTVN{sub CT}+ GTVN{sub path} - GTVN{sub CT} and {sub path}). Results: LN metastases occurred in 21 LN groups among the 144 specimens taken from the 16 patients. The area under the receiver operating characteristic curve was 0.9017 {+-} 0.0410. The plot of error rates showed a minimum of FNR+FPR for an SUV of 2.36, at which the sensitivity, specificity, and accuracy were 76.19%, 95.93%, and 93.06%, respectively, whereas those of CT were 33.33%, 94.31%, and 85.42% (p values: 0.0117, 0.7539, and 0.0266). Mean GTVN{sub CT}, GTVN{sub PET}, and GTVN{sub path} were 1.52 {+-} 2.38, 2.82 {+-} 4.51, and 2.68 {+-} 4.16cm{sup 3}, respectively. Mean CI{sub CT} and {sub path} and CI{sub PET} and {sub path

  11. A new brain positron emission tomography scanner with semiconductor detectors for target volume delineation and radiotherapy treatment planning in patients with nasopharyngeal carcinoma.

    PubMed

    Katoh, Norio; Yasuda, Koichi; Shiga, Tohru; Hasegawa, Masakazu; Onimaru, Rikiya; Shimizu, Shinichi; Bengua, Gerard; Ishikawa, Masayori; Tamaki, Nagara; Shirato, Hiroki

    2012-03-15

    We compared two treatment planning methods for stereotactic boost for treating nasopharyngeal carcinoma (NPC): the use of conventional whole-body bismuth germanate (BGO) scintillator positron emission tomography (PET(CONV)WB) versus the new brain (BR) PET system using semiconductor detectors (PET(NEW)BR). Twelve patients with NPC were enrolled in this study. [(18)F]Fluorodeoxyglucose-PET images were acquired using both the PET(NEW)BR and the PET(CONV)WB system on the same day. Computed tomography (CT) and two PET data sets were transferred to a treatment planning system, and the PET(CONV)WB and PET(NEW)BR images were coregistered with the same set of CT images. Window width and level values for all PET images were fixed at 3000 and 300, respectively. The gross tumor volume (GTV) was visually delineated on PET images by using either PET(CONV)WB (GTV(CONV)) images or PET(NEW)BR (GTV(NEW)) images. Assuming a stereotactic radiotherapy boost of 7 ports, the prescribed dose delivered to 95% of the planning target volume (PTV) was set to 2000 cGy in 4 fractions. The average absolute volume (±standard deviation [SD]) of GTV(NEW) was 15.7 ml (±9.9) ml, and that of GTV(CONV) was 34.0 (±20.5) ml. The average GTV(NEW) was significantly smaller than that of GTV(CONV) (p = 0.0006). There was no statistically significant difference between the maximum dose (p = 0.0585) and the mean dose (p = 0.2748) of PTV. The radiotherapy treatment plan based on the new gross tumor volume (PLAN(NEW)) significantly reduced maximum doses to the cerebrum and cerebellum (p = 0.0418) and to brain stem (p = 0.0041). Results of the present study suggest that the new brain PET system using semiconductor detectors can provide more accurate tumor delineation than the conventional whole-body BGO PET system and may be an important tool for functional and molecular radiotherapy treatment planning. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. A New Brain Positron Emission Tomography Scanner With Semiconductor Detectors for Target Volume Delineation and Radiotherapy Treatment Planning in Patients With Nasopharyngeal Carcinoma

    SciTech Connect

    Katoh, Norio; Yasuda, Koichi; Shiga, Tohru; Hasegawa, Masakazu; Onimaru, Rikiya; Shimizu, Shinichi; Bengua, Gerard; Ishikawa, Masayori; Tamaki, Nagara; Shirato, Hiroki

    2012-03-15

    Purpose: We compared two treatment planning methods for stereotactic boost for treating nasopharyngeal carcinoma (NPC): the use of conventional whole-body bismuth germanate (BGO) scintillator positron emission tomography (PET{sub CONV}WB) versus the new brain (BR) PET system using semiconductor detectors (PET{sub NEW}BR). Methods and Materials: Twelve patients with NPC were enrolled in this study. [{sup 18}F]Fluorodeoxyglucose-PET images were acquired using both the PET{sub NEW}BR and the PET{sub CONV}WB system on the same day. Computed tomography (CT) and two PET data sets were transferred to a treatment planning system, and the PET{sub CONV}WB and PET{sub NEW}BR images were coregistered with the same set of CT images. Window width and level values for all PET images were fixed at 3000 and 300, respectively. The gross tumor volume (GTV) was visually delineated on PET images by using either PET{sub CONV}WB (GTV{sub CONV}) images or PET{sub NEW}BR (GTV{sub NEW}) images. Assuming a stereotactic radiotherapy boost of 7 ports, the prescribed dose delivered to 95% of the planning target volume (PTV) was set to 2000 cGy in 4 fractions. Results: The average absolute volume ({+-}standard deviation [SD]) of GTV{sub NEW} was 15.7 ml ({+-}9.9) ml, and that of GTV{sub CONV} was 34.0 ({+-}20.5) ml. The average GTV{sub NEW} was significantly smaller than that of GTV{sub CONV} (p = 0.0006). There was no statistically significant difference between the maximum dose (p = 0.0585) and the mean dose (p = 0.2748) of PTV. The radiotherapy treatment plan based on the new gross tumor volume (PLAN{sub NEW}) significantly reduced maximum doses to the cerebrum and cerebellum (p = 0.0418) and to brain stem (p = 0.0041). Conclusion: Results of the present study suggest that the new brain PET system using semiconductor detectors can provide more accurate tumor delineation than the conventional whole-body BGO PET system and may be an important tool for functional and molecular radiotherapy

  13. Analysis of interfractional set-up errors and intrafractional organ motions during IMRT for head and neck tumors to define an appropriate planning target volume (PTV)- and planning organs at risk volume (PRV)-margins.

    PubMed

    Suzuki, Minoru; Nishimura, Yasumasa; Nakamatsu, Kiyoshi; Okumura, Masahiko; Hashiba, Hisayuki; Koike, Ryuta; Kanamori, Shuichi; Shibata, Toru

    2006-03-01

    To analyze the interfractional set-up errors and intrafractional organ motions and to define appropriate planning target volume (PTV)- and planning organs at risk volume (PRV)-margins in intensity-modulated radiotherapy (IMRT) for head and neck tumors. Twenty-two patients with head and neck or brain tumors who were treated with IMRT were enrolled. The set-up errors were defined as the displacements of the coordinates of bony landmarks on the beam films from those on the simulation films. The organ motions were determined as the displacements of the coordinates of the landmarks on the images recorded every 3 min for 15 min on the X-ray simulator from those on the initial image. The standard deviations (SDs) of the systematic set-up errors (Sigma-INTER) and organ motions (Sigma-intra) distributed with a range of 0.7-1.3 and 0.2-0.8 mm, respectively. The average of the SDs of the random set-up errors (sigma-INTER) and organ motions (sigma-intra) ranged from 0.7 to 1.6 mm and from 0.3 to 0.6 mm, respectively. Appropriate PTV-margins and PRV-margins for all the landmarks ranged from 2.0 to 3.6 mm and from 1.8 to 2.4 mm, respectively. We have adopted a PTV-margin of 5mm and a PRV-margin of 3mm for head and neck IMRT at our department.

  14. Determining optimal clinical target volume margins on the basis of microscopic extracapsular extension of metastatic nodes in patients with non-small-cell lung cancer

    SciTech Connect

    Yuan Shuanghu; Meng Xue; Yu Jinming . E-mail: fishtigers@yahoo.com.cn; Mu Dianbin; Chao, K.S. Clifford; Zhang Jiandong; Zhong Weixia; Yu Yonghua; Wang Jialin; Sun Xindong; Yang Guoren; Wang Yongzheng

    2007-03-01

    Purpose: To determine the optimal clinical target volume (CTV) margins around the nodal gross tumor volume (GTV) in non-small-cell lung cancer (NSCLC) patients by assessing microscopic tumor extension beyond regional lymph node capsules. Methods and Materials: The incidence of nodal extracapsular extension (ECE) and relationship with nodal size were reviewed in 243 patients. Histologic sections of dissected regional lymph nodes up to 30 mm in size were examined to measure the extent of microscopic ECE. We determined the distribution of cases according to extent of ECE and the relationships between ECE extent and lymph node size, regional nodal disease extent, histologic type, and degree of differentiation. Results: The nodal ECE was seen in 41.6% of patients (101/243) and 33.4% of lymph nodes (214/640), and the incidence correlated to larger lymph node size positively. The extent of ECE was 0.7 mm in mean (range, 0-12.0 mm) and {<=}3 mm in 95% of the nodes. Positive correlations were found between extent of ECE and larger lymph node size ({>=}20 mm vs. 10-19 mm or <10 mm, p = 0.005), advanced nodal stage (N2 vs. N1, p = 0.046), and moderate or poor (vs. good or unknown) nodal differentiation (p = 0.002). ECE did not differ significantly by histologic type or nodal station. Conclusions: The incidence of ECE related to lymph node size, and ECE extent related to lymph node size, stage, and differentiation. It may be reasonable to recommend 3-mm CTV margins for pathologic lymph nodes <20 mm and more generous margins for lymph nodes {>=}20 mm.

  15. SU-E-J-207: Assessing the Validity of 4D-CT Based Target Volumes and Free Breathing CBCT Localization in Lung Stereotactic Ablative Radiation Therapy (SABR)

    SciTech Connect

    Badkul, R; Pokhrel, D; Jiang, H; Park, J; Wang, F; Kumar, P

    2014-06-01

    Purpose: Four-dimensional-computed-tomography(4D-CT) imaging for target-volume delineation and cone-beam-tomography(CBCT) for treatment localization are widely utilized in lung-SABR.Aim of this study was to perform a quantitative-assessment and inter-comparison of Internal-targetvolumes( ITV) drawn on various phases of breathing-cycle 4D-CT-scans, Maximum-intensity-projection(MIP), average-intensity-projection(AIP)and static CT-scans of lung-motion-phantom to simulate lung-SABR patient geometry. We also analyzed and compared the ITVs drawn on freebreathing- CBCT. Materials and Methods: 4D-CT-scans were acquired on Philips big-bore 16slice CT and Bellows-respiratory monitoring-system using retrospective phase-binning method. Each respiratory cycle divided into 10-phases. Quasar-Phantom with lung-inserts and 3cm-diameter nylonball to simulate tumor and was placed on respiratory-motion-platform for 4D-CT and CBCT-acquisition. Amplitudes of motions: 0.5,1.0,2.0,3.0cm in superior-inferior direction with breathing-cycle time of 6,5,4,6sec, respectively used.4D-CTs with 10-phases(0%to90%)for each excursion-set and 3D-CT for static-phantom exported to iPlan treatment-planningsystem( TPS).Tumor-volumes delineated in all phases of 4D-CT, MIP,AIP,CBCT scans using fixed-HU-threshold(−500to1000)values automatically.For each 4D-dataset ITV obtained by unifying the tumorcontours on all phases.CBCT-ITV-volumes were drawn in Eclipse-TPS. Results: Mean volume of tumor contours for all phases compared with static 3D-CT were 0.62±0.08%, 1.67±0.26%, 4.77±0.54% and 9.27±1.23% for 0.5cm,1cm,2cm,3cm excursions respectively. Differences of mean Union-ITV with MIP-ITV were close(≤2.4%).Mean Union-ITV from expected-theoretical values differed from −4.9% to 3.8%.Union-ITV and MIP-ITV were closer within 2.3%. AIP-ITVs were underestimated from 14 to 32% compared to union-ITV for all motion datasets. Differences of −5.9% to −44% and −5% to 6.7% for CBCT-ITV from MIP-ITV and AIP

  16. SU-E-T-513: Investigating Dose of Internal Target Volume After Correcting for Tissue Heterogeneity in SBRT Lung Plans with Homogeneity Calculation

    SciTech Connect

    Qi, P; Zhuang, T; Magnelli, A; Djemil, T; Shang, Q; Balik, S; Andrews, M; Stephans, K; Videtic, G; Xia, P

    2015-06-15

    Purpose It was recommended to use the prescription of 54 Gy/3 with heterogeneity corrections for previously established dose scheme of 60 Gy/3 with homogeneity calculation. This study is to investigate dose coverage for the internal target volume (ITV) with and without heterogeneity correction. Methods Thirty patients who received stereotactic body radiotherapy (SBRT) to a dose of 60 Gy in 3 fractions with homogeneous planning for early stage non-small-cell lung cancer (NSCLC) were selected. ITV was created either from 4DCT scans or a fusion of multi-phase respiratory scans. Planning target volume (PTV) was a 5 mm expansion of the ITV. For this study, we recalculated homogeneous clinical plans using heterogeneity corrections with monitor units set as clinically delivered. All plans were calculated with 3 mm dose grids and collapsed cone convolution algorithm. To account for uncertainties from tumor delineation and image-guided radiotherapy, a structure ITV2mm was created by expanding ITV with 2 mm margins. Dose coverage to the PTV, ITV and ITV2mm were compared with a student paired t-test. Results With heterogeneity corrections, the PTV V60Gy decreased by 10.1% ± 18.4% (p<0.01) while the maximum dose to the PTV increased by 3.7 ± 4.3% (p<0.01). With and without corrections, D99% was 65.8 ± 4.0 Gy and 66.7 ± 4.8 Gy (p=0.15) for the ITV, and 63.9 ± 3.4 Gy and 62.9 ± 4.6 Gy for the ITV2mm (p=0.22), respectively. The mean dose to the ITV and ITV2mm increased 3.6% ± 4.7% (p<0.01) and 2.3% ± 5.2% (p=0.01) with heterogeneity corrections. Conclusion After heterogeneity correction, the peripheral coverage of the PTV decreased to approximately 54 Gy, but D99% of the ITV and ITV2mm was unchanged and the mean dose to the ITV and ITV2mm was increased. Clinical implication of these results requires more investigation.

  17. Highly Conformal Craniospinal Radiotherapy Techniques Can Underdose the Cranial Clinical Target Volume if Leptomeningeal Extension through Skull Base Exit Foramina is not Contoured.

    PubMed

    Noble, D J; Ajithkumar, T; Lambert, J; Gleeson, I; Williams, M V; Jefferies, S J

    2017-07-01

    Craniospinal irradiation (CSI) remains a crucial treatment for patients with medulloblastoma. There is uncertainty about how to manage meningeal surfaces and cerebrospinal fluid (CSF) that follows cranial nerves exiting skull base foramina. The purpose of this study was to assess plan quality and dose coverage of posterior cranial fossa foramina with both photon and proton therapy. We analysed the radiotherapy plans of seven patients treated with CSI for medulloblastoma and primitive neuro-ectodermal tumours and three with ependymoma (total n = 10). Four had been treated with a field-based technique and six with TomoTherapy™. The internal acoustic meatus (IAM), jugular foramen (JF) and hypoglossal canal (HC) were contoured and added to the original treatment clinical target volume (Plan_CTV) to create a Test_CTV. This was grown to a test planning target volume (Test_PTV) for comparison with a Plan_PTV. Using Plan_CTV and Plan_PTV, proton plans were generated for all 10 cases. The following dosimetry data were recorded: conformity (dice similarity coefficient) and homogeneity index (D2 - D98/D50) as well as median and maximum dose (D2%) to Plan_PTV, V95% and minimum dose (D99.9%) to Plan_CTV and Test_CTV and Plan_PTV and Test_PTV, V95% and minimum dose (D98%) to foramina PTVs. Proton and TomoTherapy™ plans were more conformal (0.87, 0.86) and homogeneous (0.07, 0.04) than field-photon plans (0.79, 0.17). However, field-photon plans covered the IAM, JF and HC PTVs better than proton plans (P = 0.002, 0.004, 0.003, respectively). TomoTherapy™ plans covered the IAM and JF better than proton plans (P = 0.000, 0.002, respectively) but the result for the HC was not significant. Adding foramen CTVs/PTVs made no difference for field plans. The mean Dmin dropped 3.4% from Plan_PTV to Test_PTV for TomoTherapy™ (not significant) and 14.8% for protons (P = 0.001). Highly conformal CSI techniques may underdose meninges and CSF in the dural reflections of

  18. SU-E-T-480: Radiobiological Dose Comparison of Single Fraction SRS, Multi-Fraction SRT and Multi-Stage SRS of Large Target Volumes Using the Linear-Quadratic Formula

    SciTech Connect

    Ding, C; Hrycushko, B; Jiang, S; Meyer, J; Timmerman, R

    2014-06-01

    Purpose: To compare the radiobiological effect on large tumors and surrounding normal tissues from single fraction SRS, multi-fractionated SRT, and multi-staged SRS treatment. Methods: An anthropomorphic head phantom with a centrally located large volume target (18.2 cm{sup 3}) was scanned using a 16 slice large bore CT simulator. Scans were imported to the Multiplan treatment planning system where a total prescription dose of 20Gy was used for a single, three staged and three fractionated treatment. Cyber Knife treatment plans were inversely optimized for the target volume to achieve at least 95% coverage of the prescription dose. For the multistage plan, the target was segmented into three subtargets having similar volume and shape. Staged plans for individual subtargets were generated based on a planning technique where the beam MUs of the original plan on the total target volume are changed by weighting the MUs based on projected beam lengths within each subtarget. Dose matrices for each plan were export in DICOM format and used to calculate equivalent dose distributions in 2Gy fractions using an alpha beta ratio of 10 for the target and 3 for normal tissue. Results: Singe fraction SRS, multi-stage plan and multi-fractionated SRT plans had an average 2Gy dose equivalent to the target of 62.89Gy, 37.91Gy and 33.68Gy, respectively. The normal tissue within 12Gy physical dose region had an average 2Gy dose equivalent of 29.55Gy, 16.08Gy and 13.93Gy, respectively. Conclusion: The single fraction SRS plan had the largest predicted biological effect for the target and the surrounding normal tissue. The multi-stage treatment provided for a more potent biologically effect on target compared to the multi-fraction SRT treatments with less biological normal tissue than single-fraction SRS treatment.

  19. Variations in target volume definition and dose to normal tissue using anatomic versus biological imaging ((18) F-FDG-PET) in the treatment of bone metastases: results from a 3-arm randomized phase II trial.

    PubMed

    Berwouts, Dieter; De Wolf, Katrien; De Neve, Wilfried; Olteanu, Luiza Am; Lambert, Bieke; Speleers, Bruno; Goethals, Ingeborg; Madani, Indira; Ost, Piet

    2017-02-01

    To report the impact on target volume delineation and dose to normal tissue using anatomic versus biological imaging ((18) F-FDG-PET) for bone metastases. Patients with uncomplicated painful bone metastases were randomized (1:1:1) and blinded to receive either 8 Gy in a single fraction with conventionally planned radiotherapy (ConvRT-8 Gy) or 8 Gy in a single fraction with dose-painting-by-numbers (DPBN) dose range between 6 and 10 Gy) (DPBN-8 Gy) or 16 Gy in a single fraction with DPBN (dose range between 14 and 18 Gy) (DPBN-16 Gy). The primary endpoint was overall pain response at 1 month. Volumes of the gross tumour volume (GTV) - both biological (GTVPET ) and anatomical (GTVCT ) -, planning target volume (PTV), dose to the normal tissue and maximum standardized-uptake values (SUVMAX ) were analysed (secondary endpoint). Sixty-three percent of the GTVCT volume did not show (18) F-FDG-uptake. On average, 20% of the GTVPET volume was outside GTVCT . The volume of normal tissue receiving 4 Gy, 6 Gy and 8 Gy was at least 3×, 6× and 13× smaller in DPBN-8 Gy compared to ConvRT-8 Gy and DPBN-16 Gy (P < 0.05). Positron emitting tomography-information potentially changes the target volume for bone metastases. DPBN between 6 and 10 Gy significantly decreases dose to the normal tissue compared to conventional radiotherapy. © 2016 The Royal Australian and New Zealand College of Radiologists.

  20. Inverse-planned, dynamic, multi-beam, intensity-modulated radiation therapy (IMRT): a promising technique when target volume is the left breast and internal mammary lymph nodes.

    PubMed

    Popescu, Carmen C; Olivotto, Ivo; Patenaude, Veronica; Wai, Elaine; Beckham, Wayne A

    2006-01-01

    The purpose of this study was to determine the optimum beam number and orientation for inverse-planned, dynamic intensity-modulated radiation therapy (IMRT) for treatment of left-sided breast cancer and internal mammary nodes (IMNs) to improve target coverage while reducing cardiac and ipsilateral lung irradiation. Computed tomography (CT) data was used from 5 patients with left-sided breast cancer in whom the heart was close to the chest wall. The planning target volume (PTV) was the full breast plus ipsilateral IMNs. Two geometric beam arrangements were investigated, 240 degrees and 190 degrees sector angles, and the number of beams was increased from 7 to 9 to 11. Dose comparison metrics included: PTV homogeneity and conformity indices (HI, CI), heart V30, left lung V20, and mean doses to surrounding structures. To assess clinical application, the IMRT plans with 11 beams equally spaced in a 190 degrees sector angle were compared to conventional plans. Treatment times were modeled. The 190 degrees IMRT plans improved PTV HI and CI and reduced mean dose to the heart, lungs, contralateral breast, and total healthy tissue (all p < 0.05) compared to a 240 degrees sector angle. The 11-beam plan significantly improved PTV HI and CI, heart V30, left lung V20, and healthy tissue V5 compared to a 7-beam plan (all p < 0.05). The 11-beam plan reduced heart V30 and left lung V20 (p < 0.05) without compromising PTV coverage, compared to a 9-beam plan. Compared to a conventional plan, the IMRT class solution significantly improved PTV HI and CI (both p < 0.01), heart V30 (p = 0.01), and marginally reduced left lung V20 (p = 0.07) but increased contralateral breast and lung mean dose (p < 0.001) and healthy tissue V5 (p < 0.001). An 11-beam 190 degrees sector angle IMRT technique as a class solution is clinically feasible.

  1. Suspect screening and target quantification of multi-class pharmaceuticals in surface water based on large-volume injection liquid chromatography and time-of-flight mass spectrometry.

    PubMed

    Vergeynst, Leendert; Van Langenhove, Herman; Joos, Pieter; Demeestere, Kristof

    2014-04-01

    The ever-growing number of emerging micropollutants such as pharmaceuticals requests rapid and sensitive full-spectrum analytical techniques. Time-of-flight high-resolution mass spectrometry (TOF-HRMS) is a promising alternative for the state-of-the-art tandem mass spectrometry instruments because of its ability to simultaneously screen for a virtually unlimited number of suspect analytes and to perform target quantification. The challenge for such suspect screening is to develop a strategy, which minimizes the false-negative rate without restraining numerous false-positives. At the same time, omitting laborious sample enrichment through large-volume injection ultra-performance liquid chromatography (LVI-UPLC) avoids selective preconcentration. A suspect screening strategy was developed using LVI-UPLC-TOF-MS aiming the detection of 69 multi-class pharmaceuticals in surface water without the a priori availability of analytical standards. As a novel approach, the screening takes into account the signal-intensity-dependent accurate mass error of TOF-MS, hereby restraining 95 % of the measured suspect pharmaceuticals present in surface water. Application on five Belgian river water samples showed the potential of the suspect screening approach, as exemplified by a false-positive rate not higher than 15 % and given that 30 out of 37 restrained suspect compounds were confirmed by the retention time of analytical standards. Subsequently, this paper discusses the validation and applicability of the LVI-UPLC full-spectrum HRMS method for target quantification of the 69 pharmaceuticals in surface water. Analysis of five Belgian river water samples revealed the occurrence of 17 pharmaceuticals in a concentration range of 17 ng L(-1) up to 3.1 μg L(-1).

  2. Distribution of lymph node metastases on FDG-PET/CT in inoperable or unresectable oesophageal cancer patients and the impact on target volume definition in radiation therapy.

    PubMed

    Machiels, Melanie; Wouterse, Sanne J; Geijsen, Elisabeth D; van Os, Rob M; Bennink, Roel J; van Laarhoven, Hanneke Wm; Hulshof, Maarten Ccm

    2016-08-01

    Definitive chemoradiotherapy (dCRT) is standard care for localised inoperable/unresectable oesophageal tumours. Many surgical series have reported on distribution of lymph node metastases (LNM) in resected patients. However, no data is available on the distribution of at-risk LN regions in this more unfavourable patient group. This study aimed to determine the spread of LNM using FDG-PET/CT, to compare it with the distribution in surgical series and to define its impact on the definition of elective LN irradiation (ENI). FDG-PET/CT images of patients with oesophageal cancer treated with dCRT (from 2003 to 2013) were reviewed to identify the anatomic distribution of FDG-avid LNs. Tumours were divided according to proximal, mid-thoracic or distal localisation. About 105 consecutive patients entered analysis. The highest numbers of FDG-avid LNs in proximal tumours were at LN station 101R (45%) and 106recL (35%). For mid-thoracic tumours at 104R (30%) and 105 (30%). For tumours located in the distal oesophagus, the most common sites were along the lesser curvature of the stomach (21%) and the left gastric artery (21%). Except for the supraclavicular and pretracheal nodes, there were no positive locoregional LNM found outside the standard surgical resection area. Our results show a good correlation between the distribution of nodal volumes at risk in surgical series and on FDG-PET/CT. The results can be used to determine target definition in dCRT for oesophageal cancer. For mid-thoracic tumours, the current target delineation guidelines may be extended based on the risk of node involvement, but more clinical studies are needed to determine if the potential harm of expanding the CTV outweighs the potential benefit. © 2016 The Royal Australian and New Zealand College of Radiologists.

  3. Native T1 Relaxation Time and Extracellular Volume Fraction as Accurate Markers of Diffuse Myocardial Fibrosis in Heart Valve Disease - Comparison With Targeted Left Ventricular Myocardial Biopsy.

    PubMed

    Kockova, Radka; Kacer, Petr; Pirk, Jan; Maly, Jiri; Sukupova, Lucie; Sikula, Viktor; Kotrc, Martin; Barciakova, Lucia; Honsova, Eva; Maly, Marek; Kautzner, Josef; Sedmera, David; Penicka, Martin

    2016-04-25

    The aim of our study was to investigate the relationship between the cardiac magnetic resonance (CMR)-derived native T1 relaxation time and myocardial extracellular volume (ECV) fraction and the extent of diffuse myocardial fibrosis (DMF) on targeted myocardial left ventricular (LV) biopsy. The study population consisted of 40 patients (age 63±8 years, 65% male) undergoing valve and/or ascending aorta surgery for severe aortic stenosis (77.5%), root dilatation (7.5%) or valve regurgitation (15%). The T1 relaxation time was assessed in the basal interventricular septum pre- and 10-min post-contrast administration using the modified Look-Locker Inversion recovery sequence prior to surgery. LV myocardial biopsy specimen was obtained during surgery from the basal interventricular septal segment matched with the T1 mapping assessment. The percentage of myocardial collagen was quantified using picrosirius red staining. The average percentage of myocardial collagen was 22.0±14.8%. Both native T1 relaxation time with cutoff value ≥1,010 ms (sensitivity=90%, specificity=73%, area under the curve=0.82) and ECV with cutoff value ≥0.32 (sensitivity=80%, specificity=90%, area under the curve=0.85) showed high accuracy to identify severe (>30%) DMF. The native T1 relaxation time showed significant correlation with LV mass (P<0.01). Native T1 relaxation time and ECV at 10 min after contrast administration are accurate markers of DMF. (Circ J 2016; 80: 1202-1209).

  4. Targeted Screening and Quantification of dl-PCBs and Dioxins in Various Foodstuffs by Programmed-temperature Vaporizer Large-volume Injection Coupled to GC-MS.

    PubMed

    Ho, Ngoc Huy; Bugey, Aurélie; Zimmerli, Pierre; Nançoz, Joëlle; Ortelli, Didier; Edder, Patrick

    2014-10-01

    In 2009, high concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) were found in soils located near the municipal garbage incinerator of Geneva. The matter of food contamination in this area was raised. Based on exposure criteria, a strategy of analysis of animal fats has been established with farmers in the Geneva area. Most methods of analysis of dl-PCBs, dioxins and furans, are based on gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS) and considered as the reference methodology. An innovative approach was developed by programmed-temperature vaporizer large-volume injection (PTV-LV) and gas chromatography coupled with triple quadrupole mass spectrometry (GC-MS/MS) analysis. This analytical method was validated and was found suitable for screening and quantification of target compounds in animal fats (beef, pork, sheep, etc. ). PTV-LV coupled to GC-MS/MS appeared to be a good alternative compared to the GC-HRMS strategy, offering a good compromise between sensitivity, versatility of instrumentation, and economical aspects. A survey of 121 samples was conducted.

  5. Consensus Guidelines for Delineation of Clinical Target Volume for Intensity-Modulated Pelvic Radiotherapy in Postoperative Treatment of Endometrial and Cervical Cancer

    SciTech Connect

    Small, William Mell, Loren K.; Anderson, Penny; Creutzberg, Carien; De Los Santos, Jennifer; Gaffney, David; Jhingran, Anuja; Portelance, Lorraine; Schefter, Tracey; Iyer, Revathy; Varia, Mahesh; Winter, Kathryn M.S.; Mundt, Arno J.

    2008-06-01

    Purpose: To develop an atlas of the clinical target volume (CTV) definitions for postoperative radiotherapy of endometrial and cervical cancer to be used for planning pelvic intensity-modulated radiotherapy. Methods and Materials: The Radiation Therapy Oncology Group led an international collaberation of cooperative groups in the development of the atlas. The groups included the Radiation Therapy Oncology Group, Gynecologic Oncology Group, National Cancer Institute of Canada, European Society of Therapeutic Radiology and Oncology, and American College of Radiology Imaging Network. The members of the group were asked by questionnaire to define the areas that were to be included in the CTV and to outline theses areas on individual computed tomography images. The initial formulation of the group began in late 2004 and culminated with a formal consensus conference in June 2005. Results: The committee achieved a consensus CTV definition for postoperative therapy for endometrial and cervical cancer. The CTV should include the common, external, and internal iliac lymph node regions. The upper 3.0 cm of the vagina and paravaginal soft tissue lateral to the vagina should also be included. For patients with cervical cancer, or endometrial cancer with cervical stromal invasion, it is also recommended that the CTV include the presacral lymph node region. Conclusion: This report serves as an international template for the definition of the CTV for postoperative intensity-modulated radiotherapy for endometrial and cervical cancer.

  6. Radiation Therapy Oncology Group Consensus Panel Guidelines for the Delineation of the Clinical Target Volume in the Postoperative Treatment of Pancreatic Head Cancer

    SciTech Connect

    Goodman, Karyn A.; Regine, William F.; Dawson, Laura A.; Ben-Josef, Edgar; Haustermans, Karin; Bosch, Walter R.; Turian, Julius; Abrams, Ross A.

    2012-07-01

    Purpose: To develop contouring guidelines to be used in the Radiation Therapy Oncology Group protocol 0848, a Phase III randomized trial evaluating the benefit of adjuvant chemoradiation in patients with resected head of pancreas cancer. Methods and Materials: A consensus committee of six radiation oncologists with expertise in gastrointestinal radiotherapy developed stepwise contouring guidelines and an atlas for the delineation of the clinical target volume (CTV) in the postoperative treatment of pancreas cancer, based on identifiable regions of interest and margin expansions. Areas at risk for subclinical disease to be included in the CTV were defined, including nodal regions, anastomoses, and the preoperative primary tumor location. Regions of interest that could be reproducibly contoured on postoperative imaging after a pancreaticoduodenectomy were identified. Standardized expansion margins to encompass areas at risk were developed after multiple iterations to determine the optimal margin expansions. Results: New contouring recommendations based on CT anatomy were established. Written guidelines for the delineation of the postoperative CTV and normal tissues, as well as a Web-based atlas, were developed. Conclusions: The postoperative abdomen has been a difficult area for effective radiotherapy. These new guidelines will help physicians create fields that better encompass areas at risk and minimize dose to normal tissues.

  7. Recommendations for high-risk clinical target volume definition with computed tomography for three-dimensional image-guided brachytherapy in cervical cancer patients.

    PubMed

    Ohno, Tatsuya; Wakatsuki, Masaru; Toita, Takafumi; Kaneyasu, Yuko; Yoshida, Ken; Kato, Shingo; Li, Noriko; Tokumaru, Sunao; Ikushima, Hitoshi; Uno, Takashi; Noda, Shin-Ei; Kazumoto, Tomoko; Harima, Yoko

    2016-11-10

    Our purpose was to develop recommendations for contouring the computed tomography (CT)-based high-risk clinical target volume (CTVHR) for 3D image-guided brachytherapy (3D-IGBT) for cervical cancer. A 15-member Japanese Radiation Oncology Study Group (JROSG) committee with expertise in gynecological radiation oncology initiated guideline development for CT-based CTVHR (based on a comprehensive literature review as well as clinical experience) in July 2014. Extensive discussions occurred during four face-to-face meetings and frequent email communication until a consensus was reached. The CT-based CTVHR boundaries were defined by each anatomical plane (cranial-caudal, lateral, or anterior-posterior) with or without tumor progression beyond the uterine cervix at diagnosis. Since the availability of magnetic resonance imaging (MRI) with applicator insertion for 3D planning is currently limited, T2-weighted MRI obtained at diagnosis and just before brachytherapy without applicator insertion was used as a reference for accurately estimating the tumor size and topography. Furthermore, utilizing information from clinical examinations performed both at diagnosis and brachytherapy is strongly recommended. In conclusion, these recommendations will serve as a brachytherapy protocol to be used at institutions with limited availability of MRI for 3D treatment planning.

  8. CONSENSUS GUIDELINES FOR THE DELINEATION OF THE CLINICAL TARGET VOLUME FOR INTENSITY MODULATED PELVIC RADIOTHERAPY IN THE POSTOPERATIVE TREATMENT OF ENDOMETRIAL AND CERVICAL CANCER

    PubMed Central

    Small, William; Mell, Loren K.; Anderson, Penny; Creutzberg, Carien; De Los Santos, Jennifer; Gaffney, David; Jhingran, Anuja; Portelance, Lorraine; Schefter, Tracey; Iyer, Revathy; Varia, Mahesh; Winter, Kathryn; Mundt, Arno J.

    2009-01-01

    PURPOSE To develop an atlas of the clinical target volumes (CTV) definitions for the post-operative radiotherapy of endometrial and cervical cancer to be utilized for planning pelvic Intensity Modulated Radiation Therapy (IMRT). METHODS AND MATERIALS The Radiation Therapy Oncology Group (RTOG) led an international collaberation of cooperative groups in development of the atlas. The groups included RTOG the Gynecologic Oncology Group (GOG), the National Cancer Institute of Canada (NCIC), the European Society of Therapeutic Radiology and Oncology (ESTRO), and the American College of Radiology Imaging Network (ACRIN). Members of the group were asked by questionnaire to define areas that were to be included in the CTV and were asked to outline theses areas on individual Computed Tomography (CT) images. The initial formulation of the group began in late 2004 and culminated with a formal consensus conference in June of 2005. RESULTS The committee achieved a consensus CTV definition for the post-operative therapy of endometrial and cervical cancer. The CTV should include the common, external, and internal iliac lymph node regions. The upper 3.0 cm of vagina and paravaginal soft tissue lateral to the vagina should also be included. For patients with cervical cancer, or endometrial cancer with cervical stromal invasion, it is also recommended that the CTV include the presacral lymph node-region. CONCLUSIONS This manuscript serves as an international template for the definition of the CTV for the post-operative IMRT of endometrial and cervical cancer. PMID:18037584

  9. Droplet Characterization and Penetration of an Ultra-Low Volume Mosquito Adulticide Spray Targeting the Asian Tiger Mosquito, Aedes albopictus, within Urban and Suburban Environments of Northeastern USA.

    PubMed

    Faraji, Ary; Unlu, Isik; Crepeau, Taryn; Healy, Sean; Crans, Scott; Lizarraga, Griffith; Fonseca, Dina; Gaugler, Randy

    2016-01-01

    Adult control of Aedes albopictus via ultra-low volume is difficult because this species occurs primarily in peridomestic habitats where obstacles such as buildings and vegetation can disrupt spray plumes and droplet dispersion. We determined droplet penetration and characterization of a pyrethroid adulticide applied from the ground at mid (46.77 ml/ha) and maximum (93.53 ml/ha) label rates within cryptic habitats of urban and suburban environments. Droplets were collected from all habitats, with no significant differences detected between locations within the same application rate or collection method. No differences were detected in droplet densities (drops per mm2) between rates within urban environments, but more droplets were collected in urban (149.93 ± 11.07 SE) than suburban sites (114.37 ± 11.32) at the maximum label rate (P = 0.003). The excellent penetration of aerosols into cryptic habitats of an urban site was likely due to the shorter spray paths afforded by our network of roads and alleys. Mid label rates displayed similar droplet density values as maximum label rates in urban areas, indicating that lower rates may be used effectively to reduce costs, lessen non-target effects, and increase environmental stewardship. Advances in formulations and technology are driving changes in adulticide applications, leading to use of the minimum effective dose for maximum efficacy, precision, and accountability.

  10. Droplet Characterization and Penetration of an Ultra-Low Volume Mosquito Adulticide Spray Targeting the Asian Tiger Mosquito, Aedes albopictus, within Urban and Suburban Environments of Northeastern USA

    PubMed Central

    Faraji, Ary; Unlu, Isik; Crepeau, Taryn; Healy, Sean; Crans, Scott; Lizarraga, Griffith; Fonseca, Dina; Gaugler, Randy

    2016-01-01

    Adult control of Aedes albopictus via ultra-low volume is difficult because this species occurs primarily in peridomestic habitats where obstacles such as buildings and vegetation can disrupt spray plumes and droplet dispersion. We determined droplet penetration and characterization of a pyrethroid adulticide applied from the ground at mid (46.77 ml/ha) and maximum (93.53 ml/ha) label rates within cryptic habitats of urban and suburban environments. Droplets were collected from all habitats, with no significant differences detected between locations within the same application rate or collection method. No differences were detected in droplet densities (drops per mm2) between rates within urban environments, but more droplets were collected in urban (149.93 ± 11.07 SE) than suburban sites (114.37 ± 11.32) at the maximum label rate (P = 0.003). The excellent penetration of aerosols into cryptic habitats of an urban site was likely due to the shorter spray paths afforded by our network of roads and alleys. Mid label rates displayed similar droplet density values as maximum label rates in urban areas, indicating that lower rates may be used effectively to reduce costs, lessen non-target effects, and increase environmental stewardship. Advances in formulations and technology are driving changes in adulticide applications, leading to use of the minimum effective dose for maximum efficacy, precision, and accountability. PMID:27116103

  11. Consensus guidelines for delineation of clinical target volume for intensity-modulated pelvic radiotherapy in postoperative treatment of endometrial and cervical cancer.

    PubMed

    Small, William; Mell, Loren K; Anderson, Penny; Creutzberg, Carien; De Los Santos, Jennifer; Gaffney, David; Jhingran, Anuja; Portelance, Lorraine; Schefter, Tracey; Iyer, Revathy; Varia, Mahesh; Winter, Kathryn; Mundt, Arno J

    2008-06-01

    To develop an atlas of the clinical target volume (CTV) definitions for postoperative radiotherapy of endometrial and cervical cancer to be used for planning pelvic intensity-modulated radiotherapy. The Radiation Therapy Oncology Group led an international collaboration of cooperative groups in the development of the atlas. The groups included the Radiation Therapy Oncology Group, Gynecologic Oncology Group, National Cancer Institute of Canada, European Society of Therapeutic Radiology and Oncology, and American College of Radiology Imaging Network. The members of the group were asked by questionnaire to define the areas that were to be included in the CTV and to outline theses areas on individual computed tomography images. The initial formulation of the group began in late 2004 and culminated with a formal consensus conference in June 2005. The committee achieved a consensus CTV definition for postoperative therapy for endometrial and cervical cancer. The CTV should include the common, external, and internal iliac lymph node regions. The upper 3.0 cm of the vagina and paravaginal soft tissue lateral to the vagina should also be included. For patients with cervical cancer, or endometrial cancer with cervical stromal invasion, it is also recommended that the CTV include the presacral lymph node region. This report serves as an international template for the definition of the CTV for postoperative intensity-modulated radiotherapy for endometrial and cervical cancer.

  12. Skin Cancer of the Head and Neck With Perineural Invasion: Defining the Clinical Target Volumes Based on the Pattern of Failure

    SciTech Connect

    Gluck, Iris; Ibrahim, Mohannad; Popovtzer, Aron; Teknos, Theodoros N.; Chepeha, Douglas B.; Prince, Mark E.; Moyer, Jeffrey S.; Bradford, Carol R.; Eisbruch, Avraham

    2009-05-01

    Purpose: To analyze patterns of failure in patients with head-and-neck cutaneous squamous cell carcinoma (HNCSCC) and clinical/radiologic evidence of perineural invasion (CPNI), in order to define neural clinical target volume (CTV) for treatment planning. Methods and Materials: Patients treated with three-dimensional (3D) conformal or intensity-modulated radiotherapy (IMRT) for HNCSCC with CPNI were included in the study. A retrospective review of the clinical charts, radiotherapy (RT) plans and radiologic studies has been conducted. Results: Eleven consecutive patients with HNCSCCs with CPNI were treated from 2000 through 2007. Most patients underwent multiple surgical procedures and RT courses. The most prevalent failure pattern was along cranial nerves (CNs), and multiple CNs were ultimately involved in the majority of cases. In all cases the involved CNs at recurrence were the main nerves innervating the primary tumor sites, as well as their major communicating nerves. We have found several distinct patterns of disease spread along specific CNs depending on the skin regions harboring the primary tumors, including multiple branches of CN V and VII. These patterns and the pertinent anatomy are detailed in the this article. Conclusions: Predictable disease spread patterns along cranial nerves supplying the primary tumor sites were found in this study. Awareness of these patterns, as well as knowledge of the relevant cranial nerve anatomy, should be the basis for CTV definition and delineation for RT treatment planning.

  13. Circumferential or sectored beam arrangements for stereotactic body radiation therapy (SBRT) of primary lung tumors: Effect on target and normal-structure dose-volume metrics

    SciTech Connect

    Rosenberg, Mara W.; Kato, Catherine M.; Carson, Kelly M.P.; Matsunaga, Nathan M.; Arao, Robert F.; Doss, Emily J.; McCracken, Charles L.; Meng, Lu Z.; Chen, Yiyi; Laub, Wolfram U.; Fuss, Martin; Tanyi, James A.

    2013-01-01

    To compare 2 beam arrangements, sectored (beam entry over ipsilateral hemithorax) vs circumferential (beam entry over both ipsilateral and contralateral lungs), for static-gantry intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) delivery techniques with respect to target and organs-at-risk (OAR) dose-volume metrics, as well as treatment delivery efficiency. Data from 60 consecutive patients treated using stereotactic body radiation therapy (SBRT) for primary non–small-cell lung cancer (NSCLC) formed the basis of this study. Four treatment plans were generated per data set: IMRT/VMAT plans using sectored (-s) and circumferential (-c) configurations. The prescribed dose (PD) was 60 Gy in 5 fractions to 95% of the planning target volume (PTV) (maximum PTV dose ∼ 150% PD) for a 6-MV photon beam. Plan conformality, R{sub 50} (ratio of volume circumscribed by the 50% isodose line and the PTV), and D{sub 2} {sub cm} (D{sub max} at a distance ≥2 cm beyond the PTV) were evaluated. For lungs, mean doses (mean lung dose [MLD]) and percent V{sub 30}/V{sub 20}/V{sub 10}/V{sub 5} Gy were assessed. Spinal cord and esophagus D{sub max} and D{sub 5}/D{sub 50} were computed. Chest wall (CW) D{sub max} and absolute V{sub 30}/V{sub 20}/V{sub 10}/V{sub 5} {sub Gy} were reported. Sectored SBRT planning resulted in significant decrease in contralateral MLD and V{sub 10}/V{sub 5} {sub Gy}, as well as contralateral CW D{sub max} and V{sub 10}/V{sub 5} {sub Gy} (all p < 0.001). Nominal reductions of D{sub max} and D{sub 5}/D{sub 50} for the spinal cord with sectored planning did not reach statistical significance for static-gantry IMRT, although VMAT metrics did show a statistically significant decrease (all p < 0.001). The respective measures for esophageal doses were significantly lower with sectored planning (p < 0.001). Despite comparable dose conformality, irrespective of planning configuration, R{sub 50} significantly improved with IMRT

  14. TU-EF-304-02: 4D Optimized Treatment Planning for Actively Scanned Proton Therapy Delivered to Moving Target Volume

    SciTech Connect

    Bernatowicz, K; Zhang, Y; Weber, D; Lomax, A

    2015-06-15

    Purpose: To develop a 4D treatment optimization approach for Pencil Beam Scanned (PBS) proton therapy that includes breathing variability. Method: PBS proton therapy delivers a pattern of proton pencil beams (PBs), distributed to cover the target volume and optimized such as to achieve a homogenous dose distribution across the target. In this work, this optimization step has been enhanced to include advanced 4D dose calculations of liver tumors based on motion extracted from either 4D-CT (representing a single and averaged respiratory cycle) or 4D-CT(MRI) (including breathing variability). The 4D dose calculation is performed per PB on deforming dose grid, and according to the timestamp of each PB, a displacement due to patient’s motion and a change in radiological depth.Three different treatment fields have been optimized in 3D on the end-exhale phase of a 4D-CT liver data set (3D-opt) and then in 4D using the motion extracted from either 4D-CT or 4D-CT(MRI) using deformable image registration. All plans were calculated directly on the PTV without the use of an ITV. The delivery characteristics of the PSI Gantry 2 have been assumed for all calculations. Results: Dose inhomogeneities (D5-D95) in the CTV for the 3D optimized plans recalculated under conditions of variable motion were increased by on average 19.8% compared to the static case. These differences could be reduced by 4D-CT based 4D optimization to 10.5% and by 4D-CT(MRI) based optimization to only 2.3% of the static value. Liver V25 increased by less than 1% using 4D optimization. Conclusion: 4D optimized PBS treatment plans taking into account breathing variability provide for significantly improved robustness against motion and motion variability than those based on 4D-CT alone, and may negate the need of motion specific target expansions. Swiss National Fund Grant (320030-1493942-1)

  15. Inverse-planned, dynamic, multi-beam, intensity-modulated radiation therapy (IMRT): A promising technique when target volume is the left breast and internal mammary lymph nodes

    SciTech Connect

    Popescu, Carmen C. . E-mail: cpopescu@bccancer.bc.ca; Olivotto, Ivo; Patenaude, Veronica; Wai, Elaine; Beckham, Wayne A.

    2006-01-01

    The purpose of this study was to determine the optimum beam number and orientation for inverse-planned, dynamic intensity-modulated radiation therapy (IMRT) for treatment of left-sided breast cancer and internal mammary nodes (IMNs) to improve target coverage while reducing cardiac and ipsilateral lung irradiation. Computed tomography (CT) data was used from 5 patients with left-sided breast cancer in whom the heart was close to the chest wall. The planning target volume (PTV) was the full breast plus ipsilateral IMNs. Two geometric beam arrangements were investigated, 240{sup o} and 190{sup o} sector angles, and the number of beams was increased from 7 to 9 to 11. Dose comparison metrics included: PTV homogeneity and conformity indices (HI, CI), heart V30, left lung V20, and mean doses to surrounding structures. To assess clinical application, the IMRT plans with 11 beams equally spaced in a 190{sup o} sector angle were compared to conventional plans. Treatment times were modeled. The 190{sup o} IMRT plans improved PTV HI and CI and reduced mean dose to the heart, lungs, contralateral breast, and total healthy tissue (all p < 0.05) compared to a 240{sup o} sector angle. The 11-beam plan significantly improved PTV HI and CI, heart V30, left lung V20, and healthy tissue V5 compared to a 7-beam plan (all p < 0.05). The 11-beam plan reduced heart V30 and left lung V20 (p < 0.05) without compromising PTV coverage, compared to a 9-beam plan. Compared to a conventional plan, the IMRT class solution significantly improved PTV HI and CI (both p < 0.01), heart V30 (p = 0.01), and marginally reduced left lung V20 (p = 0.07) but increased contralateral breast and lung mean dose (p < 0.001) and healthy tissue V5 (p < 0.001). An 11-beam 190{sup o} sector angle IMRT technique as a class solution is clinically feasible.

  16. SU-E-J-88: Margin Reduction of Level II/III Planning Target Volume for Image-Guided Simultaneous Integrated Boost Head-And-Neck Treatment

    SciTech Connect

    Can, S; Neylon, J; Qi, S; Santhanam, A; Low, D

    2014-06-01

    Purpose: To investigate the feasibility of improved normal tissue sparing for head-and-neck (H'N) image-guided radiotherapy (IGRT) by employing tighter CTV-to-PTV margins for target level II/III though a GPU-based deformable image registration and dose accumulation framework. Methods: Ten H'N simultaneous integrated boost cases treated on TomoTherapy were retrospectively analyzed. Weekly kVCT scans in addition to daily MVCT scans were acquired for each patient. Reduced margin plans were generated with 0- mm margin for level II and III PTV (while 3-5 mm margin for PTV1) and compared with the standard margin plan using 3-5mm margin to all CTV1-3 (reference plan). An in-house developed GPU-based 3D image deformation tool was used to register and deform the weekly KVCTs with the planning CT and determine the delivered mean/minimum/maximum dose, dose volume histograms (DVHs), etc. Results: Compared with the reference plans, the averaged cord maximum, the right and left parotid doses reduced by 22.7 %, 16.5 %, and 9 % respectively in the reduced margin plans. The V95 for PTV2 and PTV3 were found within 2 and 5% between the reference and tighter margin plans. For the reduced margin plans, the averaged cumulative mean doses were consistent with the planned dose for PTV1, PTV2 and PTV3 within 1.5%, 1.7% and 1.4%. Similar dose variations of the delivered dose were seen for the reference and tighter margin plans. The delivered maximum and mean doses for the cord were 3.55 % and 2.37% higher than the planned doses; a 5 % higher cumulative mean dose for the parotids was also observed for the delivered dose than the planned doses in both plans. Conclusion: By imposing tighter CTV-to-PTV margins for level II and III targets for H'N irradiation, acceptable cumulative doses were achievable when coupled with weekly kVCT guidance while improving normal structure sparing.

  17. Patterns of Failure after Radical Surgery among Patients with Thoracic Esophageal Squamous Cell Carcinoma: Implications for the Clinical Target Volume Design of Postoperative Radiotherapy

    PubMed Central

    Wu, Bin; Zhu, Zheng-Fei; Chen, Hai-Quan; Fu, Xiao-Long

    2014-01-01

    Background This study evaluated patterns of treatment failure (especially locoregional failure; LRF) after radical esophagectomy and proposes a clinical target volume (CTV) for postoperative radiotherapy (PORT) among patients with thoracic esophageal squamous cell carcinoma (SCC). Methods All patients who were followed up in our center after radical esophagectomy between 2007 and 2011 were retrospectively enrolled. The patterns of first discovered failure were assessed, and LRFs (including anastomotic and regional lymph node recurrences) were evaluated to determine whether our proposed PORT CTV encompassed these areas. The clinicopathologic factors predictive of lymphatic recurrence type were analyzed. Results Of the 414 patients who underwent surgery and were followed up over the study, 207 experienced recurrent or metastatic diseases. The median time to progression was 11.0 months. Of the 173 patients with locoregional recurrence, nodal failure recurred in 160; supraclavicular and superior mediastinal lymph nodes had the highest metastasis rates. All 233 recurrent sites across the 160 patients were located in a standard CTV area, including the bilateral supraclavicular areas, the entire mediastinum, and the left gastric lymphatic drainage region. A total of 203 sites (87.2%) were located in either the bilateral supraclavicular areas or the entire mediastinum, and 185 sites (79.4%) were located in either the bilateral supraclavicular areas or the upper mediastinum. A multivariate analysis revealed the lymph node metastatic ratio (LNMR) and tumor differentiation were risk factors for nodal failure. Conclusions Locoregional recurrence (especially lymph node recurrence) was the most common and potentially preventable type of initial treatment failure after curative surgery among patients with thoracic esophageal SCC. The proposed PORT CTV covered most LRF sites. The lymphatic drainage regions for PORT are selective, and the supraclavicular and superior mediastinal

  18. Radiotherapy for solitary extramedullary plasmacytoma in the head-and-neck region: A dose greater than 45 gy to the target volume improves the local control

    SciTech Connect

    Tournier-Rangeard, Laetitia . E-mail: l.tournier@nancy.fnclcc.fr; Lapeyre, Michel; Graff-Caillaud, Pierre; Mege, Alice; Dolivet, Gilles; Toussaint, Bruno; Charra-Brunaud, Claire; Hoffstetter, Sylvette; Marchal, Christian; Peiffert, Didier

    2006-03-15

    Purpose: Our aim was to determine the dose to the clinical target volume (CTV) required for solitary extramedullary plasmacytoma (EMP) in the head and neck (HN). Methods and Materials: Seventeen patients (15 Stage I and 2 Stage II) were treated for HN EMP at our institution between 1979 and 2003. The mean International Commission on Radiation Units (ICRU) dose prescribed to the CTV was 52.6 Gy (range, 40-65 Gy) over 24 fractions (range: 20-30). The Stage II patients received neck irradiation doses of 40 and 60 Gy. A mean dose of 36.4 Gy was used for 5 Stage I patients who received elective neck irradiation. Dose administrated to the CTV was evaluated from dosimetric data or from planning films when dosimetric data were not available. Two groups of patients were distinguished: CTV covered with a dose greater than 40 Gy and CTV covered with a dose greater than 45 Gy. Results: The 5-year local control was 72.8%. It was 100% for patients who received dose to the CTV {<=} 45 Gy vs. 50% for dose to the CTV <45 Gy (p = 0.034). The prognostic factor for 5-year disease-specific survival (81.6%) was local control (p = 0.058). The prognostic factors for disease-free survival (64.1%) were monoclonal immunoglobulin secretion (p = 0.008) and a CTV dose {<=} 45 Gy (p = 0.056) Conclusions: Local control of EMP in the HN seems to be improved when the dose to the CTV is {<=} 45 Gy. A minimum dose of 45 Gy should be recommended to the CTV.

  19. Clinicopathologic analysis of extracapsular extension in prostate cancer: Should the clinical target volume be expanded posterolaterally to account for microscopic extension?

    SciTech Connect

    Chao, K. Kenneth; Goldstein, Neal S.; Yan Di; Vargas, Carlos E.; Ghilezan, Michel I.; Korman, Howard J.; Kernen, Kenneth M.; Hollander, Jay B.; Gonzalez, Jose A.; Martinez, Alvaro A.; Vicini, Frank A.; Kestin, Larry L. . E-mail: lkestin@beaumont.edu

    2006-07-15

    Purpose: We performed a complete pathologic analysis examining extracapsular extension (ECE) and microscopic spread of malignant cells beyond the prostate capsule to determine whether and when clinical target volume (CTV) expansion should be performed. Methods and Materials: A detailed pathologic analysis was performed for 371 prostatectomy specimens. All slides from each case were reviewed by a single pathologist (N.S.G.). The ECE status and ECE distance, defined as the maximal linear radial distance of malignant cells beyond the capsule, were recorded. Results: A total of 121 patients (33%) were found to have ECE (68 unilateral, 53 bilateral). Median ECE distance = 2.4 mm [range: 0.05-7.0 mm]. The 90th-percentile distance = 5.0 mm. Of the 121 cases with ECE, 55% had ECE distance {>=}2 mm, 19% {>=}4 mm, and 6% {>=}6 mm. ECE occurred primarily posterolaterally along the neurovascular bundle in all cases. Pretreatment prostrate-specific antigen (PSA), biopsy Gleason, pathologic Gleason, clinical stage, bilateral involvement, positive margins, percentage of gland involved, and maximal tumor dimension were associated with presence of ECE. Both PSA and Gleason score were associated with ECE distance. In all 371 patients, for those with either pretreatment PSA {>=}10 or biopsy Gleason score {>=}7, 21% had ECE {>=}2 mm and 5% {>=}4 mm beyond the capsule. For patients with both of these risk factors, 49% had ECE {>=}2 mm and 21% {>=}4 mm. Conclusions: For prostate cancer with ECE, the median linear distance of ECE was 2.4 mm and occurred primarily posterolaterally. Although only 5% of patients demonstrate ECE >4 to 5 mm beyond the capsule, this risk may exceed 20% in patients with PSA {>=}10 ng/ml and biopsy Gleason score {>=}7. As imaging techniques improve for prostate capsule delineation and as radiotherapy delivery techniques increase in accuracy, a posterolateral CTV expansion should be considered for patients at high risk.

  20. Total target volume is a better predictor of whole brain dose from gamma stereotactic radiosurgery than the number, shape, or location of the lesions

    PubMed Central

    Narayanasamy, Ganesh; Smith, Adam; Van Meter, Emily; McGarry, Ronald; Molloy, Janelle A.

    2013-01-01

    Purpose: To assess the hypothesis that the volume of whole brain that receives a certain dose level is primarily dependent on the treated volume rather than on the number, shape, or location of the lesions. This would help a physician validate the suitability of GammaKnife® based stereotactic radiosurgery (GKSR) prior to treatment. Methods: Simulation studies were performed to establish the hypothesis for both oblong and spherical shaped lesions of various numbers and sizes. Forty patients who underwent GKSR [mean age of 54 years (range 7–80), mean number of lesions of 2.5 (range 1–6), and mean lesion volume of 4.4 cm3 (range 0.02–22.2 cm3)] were also studied retrospectively. Following recommendations of QUANTEC, the volume of brain irradiated by the 12 Gy (VB12) isodose line was measured and a power-law based relation is proposed here for estimating VB12 from the known tumor volume and the prescription dose. Results: In the simulation study on oblong, spherical, and multiple lesions, the volume of brain irradiated by 50%, 10%, and 1% of maximum dose was found to have linear, linear, and exponentially increasing dependence on the volume of the treated region, respectively. In the retrospective study on 40 GKSR patients, a similar relationship was found to predict the brain dose with a Spearman correlation coefficient >0.9. In both the studies, the volume of brain irradiated by a certain dose level does not have a statistically significant relationship (p ≥ 0.05) with the number, shape, or position of the lesions. The measured VB12 agrees with calculation to within 1.7%. Conclusions: The results from the simulation and the retrospective clinical studies indicate that the volume of whole brain that receives a certain percentage of the maximum dose is primarily dependent on the treated volume and less on the number, shape, and location of the lesions. PMID:24007147

  1. Total target volume is a better predictor of whole brain dose from gamma stereotactic radiosurgery than the number, shape, or location of the lesions.

    PubMed

    Narayanasamy, Ganesh; Smith, Adam; Van Meter, Emily; McGarry, Ronald; Molloy, Janelle A

    2013-09-01

    To assess the hypothesis that the volume of whole brain that receives a certain dose level is primarily dependent on the treated volume rather than on the number, shape, or location of the lesions. This would help a physician validate the suitability of GammaKnife(®) based stereotactic radiosurgery (GKSR) prior to treatment. Simulation studies were performed to establish the hypothesis for both oblong and spherical shaped lesions of various numbers and sizes. Forty patients who underwent GKSR [mean age of 54 years (range 7-80), mean number of lesions of 2.5 (range 1-6), and mean lesion volume of 4.4 cm(3) (range 0.02-22.2 cm(3))] were also studied retrospectively. Following recommendations of QUANTEC, the volume of brain irradiated by the 12 Gy (VB12) isodose line was measured and a power-law based relation is proposed here for estimating VB12 from the known tumor volume and the prescription dose. In the simulation study on oblong, spherical, and multiple lesions, the volume of brain irradiated by 50%, 10%, and 1% of maximum dose was found to have linear, linear, and exponentially increasing dependence on the volume of the treated region, respectively. In the retrospective study on 40 GKSR patients, a similar relationship was found to predict the brain dose with a Spearman correlation coefficient >0.9. In both the studies, the volume of brain irradiated by a certain dose level does not have a statistically significant relationship (p ≥ 0.05) with the number, shape, or position of the lesions. The measured VB12 agrees with calculation to within 1.7%. The results from the simulation and the retrospective clinical studies indicate that the volume of whole brain that receives a certain percentage of the maximum dose is primarily dependent on the treated volume and less on the number, shape, and location of the lesions.

  2. Toward optimal organ at risk sparing in complex volumetric modulated arc therapy: An exponential trade-off with target volume dose homogeneity

    SciTech Connect

    Tol, Jim P. Dahele, Max; Doornaert, Patricia; Slotman, Ben J.; Verbakel, Wilko F. A. R.

    2014-02-15

    Purpose: Conventional radiotherapy typically aims for homogenous dose in the planning target volume (PTV) while sparing organs at risk (OAR). The authors quantified and characterized the trade-off between PTV dose inhomogeneity (IH) and OAR sparing in complex head and neck volumetric modulated arc therapy plans. Methods: Thirteen simultaneous integrated boost plans were created per patient, for ten patients. PTV boost{sub (B)}/elective{sub (E)} optimization priorities were systematically increased. IH{sub B} and IH{sub E}, defined as (100% − V95%) + V107%, were evaluated against the average of the mean dose to the combined composite swallowing and combined salivary organs (D-OAR{sub comp}). To investigate the influence of OAR size and position with respect to PTV{sub B/E}, OAR dose was evaluated against a modified Euclidean distance (DM{sub B}/DM{sub E}) between OAR and PTV. Results: Although the achievable D-OAR{sub comp} for a given level of PTV IH differed between patients, excellent logarithmic fits described the D-OAR{sub comp}/IH{sub B} and IH{sub E} relationship in all patients (mean R{sup 2} of 0.98 and 0.97, respectively). Allowing an increase in average IH{sub B} and IH{sub E} over a clinically acceptable range, e.g., from 0.4% ± 0.5% to 2.0% ± 2.0% and 6.9% ± 2.8% to 14.8% ± 2.7%, respectively, corresponded to a decrease in average dose to the composite salivary and swallowing structures from 30.3 ± 6.5 to 23.6 ± 4.7 Gy and 32.5 ± 8.3 to 26.8 ± 9.3 Gy. The increase in PTV{sub E} IH was mainly accounted for by an increase in V107, by on average 5.9%, rather than a reduction in V95, which was on average only 2%. A linear correlation was found between the OAR dose to composite swallowing structures and contralateral parotid and submandibular gland, with DM{sub E} (R{sup 2} = 0.83, 0.88, 0.95). Only mean ipsilateral parotid dose correlated with DM{sub B} (R{sup 2} = 0.87). Conclusions: OAR sparing is highly dependent on the permitted PTV{sub B

  3. Automatic segmentation of the clinical target volume and organs at risk in the planning CT for rectal cancer using deep dilated convolutional neural networks.

    PubMed

    Men, Kuo; Dai, Jianrong; Li, Yexiong

    2017-09-30

    Delineation of the clinical target volume (CTV) and organs at risk (OARs) is very important for radiotherapy but is time-consuming and prone to inter-observer variation. Here, we proposed a novel deep dilated convolutional neural network (DDCNN)-based method for fast and consistent auto-segmentation of these structures. Our DDCNN method was an end-to-end architecture enabling fast training and testing. Specifically, it employed a novel multiple-scale convolutional architecture to extract multiple-scale context features in the early layers, which contain the original information on fine texture and boundaries and which are very useful for accurate auto-segmentation. In addition, it enlarged the receptive fields of dilated convolutions at the end of networks to capture complementary context features. Then, it replaced the fully connected layers with fully convolutional layers to achieve pixel-wise segmentation. We used data from 278 patients with rectal cancer for evaluation. The CTV and OARs were delineated and validated by senior radiation oncologists in the planning computed tomography (CT) images. A total of 218 patients chosen randomly were used for training, and the remaining 60 for validation. The Dice similarity coefficient (DSC) was used to measure segmentation accuracy. Performance was evaluated on segmentation of the CTV and OARs. In addition, the performance of DDCNN was compared with that of U-Net. The proposed DDCNN method outperformed the U-Net for all segmentations, and the average DSC value of DDCNN was 3.8% higher than that of U-Net. Mean DSC values of DDCNN were 87.7% for the CTV, 93.4% for the bladder, 92.1% for the left femoral head, 92.3% for the right femoral head, 65.3% for the intestine and 61.8% for the colon. The test time was 45 s per patient for segmentation of all the CTV, bladder, left and right femoral heads, colon and intestine. We also assessed our approaches and results with those in the literature: our system showed superior

  4. SU-E-J-76: Incorporation of Ultrasound Elastography in Target Volume Delineation for Partial Breast Radiotherapy Planning: A Comparative Study

    SciTech Connect

    Juneja, P; Harris, E; Bamber, J

    2014-06-01

    Purpose: There is substantial observer variability in the delineation of target volumes for post-surgical partial breast radiotherapy because the tumour bed has poor x-ray contrast. This variability may result in substantial variations in planned dose distribution. Ultrasound elastography (USE) has an ability to detect mechanical discontinuities and therefore, the potential to image the scar and distortion in breast tissue architecture. The goal of this study was to compare USE techniques: strain elastography (SE), shear wave elastography (SWE) and acoustic radiation force impulse (ARFI) imaging using phantoms that simulate features of the tumour bed, for the purpose of incorporating USE in breast radiotherapy planning. Methods: Three gelatine-based phantoms (10% w/v) containing: a stiff inclusion (gelatine 16% w/v) with adhered boundaries, a stiff inclusion (gelatine 16% w/v) with mobile boundaries and fluid cavity inclusion (to mimic seroma), were constructed and used to investigate the USE techniques. The accuracy of the elastography techniques was quantified by comparing the imaged inclusion with the modelled ground-truth using the Dice similarity coefficient (DSC). For two regions of interest (ROI), the DSC measures their spatial overlap. Ground-truth ROIs were modelled using geometrical measurements from B-mode images. Results: The phantoms simulating stiff scar tissue with adhered and mobile boundaries and seroma were successfully developed and imaged using SE and SWE. The edges of the stiff inclusions were more clearly visible in SE than in SWE. Subsequently, for all these phantoms the measured DSCs were found to be higher for SE (DSCs: 0.91–0.97) than SWE (DSCs: 0.68–0.79) with an average relative difference of 23%. In the case of seroma phantom, DSC values for SE and SWE were similar. Conclusion: This study presents a first attempt to identify the most suitable elastography technique for use in breast radiotherapy planning. Further analysis will

  5. Toward optimal organ at risk sparing in complex volumetric modulated arc therapy: An exponential trade-off with target volume dose homogeneity

    SciTech Connect

    Tol, Jim P. Dahele, Max; Doornaert, Patricia; Slotman, Ben J.; Verbakel, Wilko F. A. R.

    2014-02-15

    Purpose: Conventional radiotherapy typically aims for homogenous dose in the planning target volume (PTV) while sparing organs at risk (OAR). The authors quantified and characterized the trade-off between PTV dose inhomogeneity (IH) and OAR sparing in complex head and neck volumetric modulated arc therapy plans. Methods: Thirteen simultaneous integrated boost plans were created per patient, for ten patients. PTV boost{sub (B)}/elective{sub (E)} optimization priorities were systematically increased. IH{sub B} and IH{sub E}, defined as (100% − V95%) + V107%, were evaluated against the average of the mean dose to the combined composite swallowing and combined salivary organs (D-OAR{sub comp}). To investigate the influence of OAR size and position with respect to PTV{sub B/E}, OAR dose was evaluated against a modified Euclidean distance (DM{sub B}/DM{sub E}) between OAR and PTV. Results: Although the achievable D-OAR{sub comp} for a given level of PTV IH differed between patients, excellent logarithmic fits described the D-OAR{sub comp}/IH{sub B} and IH{sub E} relationship in all patients (mean R{sup 2} of 0.98 and 0.97, respectively). Allowing an increase in average IH{sub B} and IH{sub E} over a clinically acceptable range, e.g., from 0.4% ± 0.5% to 2.0% ± 2.0% and 6.9% ± 2.8% to 14.8% ± 2.7%, respectively, corresponded to a decrease in average dose to the composite salivary and swallowing structures from 30.3 ± 6.5 to 23.6 ± 4.7 Gy and 32.5 ± 8.3 to 26.8 ± 9.3 Gy. The increase in PTV{sub E} IH was mainly accounted for by an increase in V107, by on average 5.9%, rather than a reduction in V95, which was on average only 2%. A linear correlation was found between the OAR dose to composite swallowing structures and contralateral parotid and submandibular gland, with DM{sub E} (R{sup 2} = 0.83, 0.88, 0.95). Only mean ipsilateral parotid dose correlated with DM{sub B} (R{sup 2} = 0.87). Conclusions: OAR sparing is highly dependent on the permitted PTV{sub B

  6. SU-E-T-364: Estimating the Minimum Number of Patients Required to Estimate the Required Planning Target Volume Margins for Prostate Glands

    SciTech Connect

    Bakhtiari, M; Schmitt, J; Sarfaraz, M; Osik, C

    2015-06-15

    Purpose: To establish a minimum number of patients required to obtain statistically accurate Planning Target Volume (PTV) margins for prostate Intensity Modulated Radiation Therapy (IMRT). Methods: A total of 320 prostate patients, consisting of a total number of 9311 daily setups, were analyzed. These patients had gone under IMRT treatments. Daily localization was done using the skin marks and the proper shifts were determined by the CBCT to match the prostate gland. The Van Herk formalism is used to obtain the margins using the systematic and random setup variations. The total patient population was divided into different grouping sizes varying from 1 group of 320 patients to 64 groups of 5 patients. Each grouping was used to determine the average PTV margin and its associated standard deviation. Results: Analyzing all 320 patients lead to an average Superior-Inferior margin of 1.15 cm. The grouping with 10 patients per group (32 groups) resulted to an average PTV margin between 0.6–1.7 cm with the mean value of 1.09 cm and a standard deviation (STD) of 0.30 cm. As the number of patients in groups increases the mean value of average margin between groups tends to converge to the true average PTV of 1.15 cm and STD decreases. For groups of 20, 64, and 160 patients a Superior-Inferior margin of 1.12, 1.14, and 1.16 cm with STD of 0.22, 0.11, and 0.01 cm were found, respectively. Similar tendency was observed for Left-Right and Anterior-Posterior margins. Conclusion: The estimation of the required margin for PTV strongly depends on the number of patients studied. According to this study at least ∼60 patients are needed to calculate a statistically acceptable PTV margin for a criterion of STD < 0.1 cm. Numbers greater than ∼60 patients do little to increase the accuracy of the PTV margin estimation.

  7. More Accurate Definition of Clinical Target Volume Based on the Measurement of Microscopic Extensions of the Primary Tumor Toward the Uterus Body in International Federation of Gynecology and Obstetrics Ib-IIa Squamous Cell Carcinoma of the Cervix

    SciTech Connect

    Xie, Wen-Jia; Wu, Xiao; Xue, Ren-Liang; Lin, Xiang-Ying; Kidd, Elizabeth A.; Yan, Shu-Mei; Zhang, Yao-Hong; Zhai, Tian-Tian; Lu, Jia-Yang; Wu, Li-Li; Zhang, Hao; Huang, Hai-Hua; Chen, Zhi-Jian; Li, De-Rui; Xie, Liang-Xi

    2015-01-01

    Purpose: To more accurately define clinical target volume for cervical cancer radiation treatment planning by evaluating tumor microscopic extension toward the uterus body (METU) in International Federation of Gynecology and Obstetrics stage Ib-IIa squamous cell carcinoma of the cervix (SCCC). Patients and Methods: In this multicenter study, surgical resection specimens from 318 cases of stage Ib-IIa SCCC that underwent radical hysterectomy were included. Patients who had undergone preoperative chemotherapy, radiation, or both were excluded from this study. Microscopic extension of primary tumor toward the uterus body was measured. The association between other pathologic factors and METU was analyzed. Results: Microscopic extension toward the uterus body was not common, with only 12.3% of patients (39 of 318) demonstrating METU. The mean (±SD) distance of METU was 0.32 ± 1.079 mm (range, 0-10 mm). Lymphovascular space invasion was associated with METU distance and occurrence rate. A margin of 5 mm added to gross tumor would adequately cover 99.4% and 99% of the METU in the whole group and in patients with lymphovascular space invasion, respectively. Conclusion: According to our analysis of 318 SCCC specimens for METU, using a 5-mm gross tumor volume to clinical target volume margin in the direction of the uterus should be adequate for International Federation of Gynecology and Obstetrics stage Ib-IIa SCCC. Considering the discrepancy between imaging and pathologic methods in determining gross tumor volume extent, we recommend a safer 10-mm margin in the uterine direction as the standard for clinical practice when using MRI for contouring tumor volume.

  8. High-Grade Glioma Radiation Therapy Target Volumes and Patterns of Failure Obtained From Magnetic Resonance Imaging and {sup 18}F-FDOPA Positron Emission Tomography Delineations From Multiple Observers

    SciTech Connect

    Kosztyla, Robert; Chan, Elisa K.; Hsu, Fred; Wilson, Don; Ma, Roy; Cheung, Arthur; Zhang, Susan; Moiseenko, Vitali; Benard, Francois; Nichol, Alan

    2013-12-01

    Purpose: The objective of this study was to compare recurrent tumor locations after radiation therapy with pretreatment delineations of high-grade gliomas from magnetic resonance imaging (MRI) and 3,4-dihydroxy-6-[{sup 18}F]fluoro-L-phenylalanine ({sup 18}F-FDOPA) positron emission tomography (PET) using contours delineated by multiple observers. Methods and Materials: Nineteen patients with newly diagnosed high-grade gliomas underwent computed tomography (CT), gadolinium contrast-enhanced MRI, and {sup 18}F-FDOPA PET/CT. The image sets (CT, MRI, and PET/CT) were registered, and 5 observers contoured gross tumor volumes (GTVs) using MRI and PET. Consensus contours were obtained by simultaneous truth and performance level estimation (STAPLE). Interobserver variability was quantified by the percentage of volume overlap. Recurrent tumor locations after radiation therapy were contoured by each observer using CT or MRI. Consensus recurrence contours were obtained with STAPLE. Results: The mean interobserver volume overlap for PET GTVs (42% ± 22%) and MRI GTVs (41% ± 22%) was not significantly different (P=.67). The mean consensus volume was significantly larger for PET GTVs (58.6 ± 52.4 cm{sup 3}) than for MRI GTVs (30.8 ± 26.0 cm{sup 3}, P=.003). More than 95% of the consensus recurrence volume was within the 95% isodose surface for 11 of 12 (92%) cases with recurrent tumor imaging. Ten (91%) of these cases extended beyond the PET GTV, and 9 (82%) were contained within a 2-cm margin on the MRI GTV. One recurrence (8%) was located outside the 95% isodose surface. Conclusions: High-grade glioma contours obtained with {sup 18}F-FDOPA PET had similar interobserver agreement to volumes obtained with MRI. Although PET-based consensus target volumes were larger than MRI-based volumes, treatment planning using PET-based volumes may not have yielded better treatment outcomes, given that all but 1 recurrence extended beyond the PET GTV and most were contained by a 2-cm

  9. A comparative study of the target volume definition in radiotherapy with «Slow CT Scan» vs. 4D PET/CT Scan in early stages non-small cell lung cancer.

    PubMed

    Molla, M; Anducas, N; Simó, M; Seoane, A; Ramos, M; Cuberas-Borros, G; Beltran, M; Castell, J; Giralt, J

    To evaluate the use of 4D PET/CT to quantify tumor respiratory motion compared to the «Slow»-CT (CTs) in the radiotherapy planning process. A total of 25 patients with inoperable early stage non small cell lung cancer (NSCLC) were included in the study. Each patient was imaged with a CTs (4s/slice) and 4D PET/CT. The adequacy of each technique for respiratory motion capture was evaluated using the volume definition for each of the following: Internal target volume (ITV) 4D and ITVslow in relation with the volume defined by the encompassing volume of 4D PET/CT and CTs (ITVtotal). The maximum distance between the edges of the volume defined by each technique to that of the total volume was measured in orthogonal beam's eye view. The ITV4D showed less differences in relation with the ITVtotal in both the cranio-caudal and the antero-posterior axis compared to the ITVslow. The maximum differences were 0.36mm in 4D PET/CTand 0.57mm in CTs in the antero-posterior axis. 4D PET/CT resulted in the definition of more accurate (ITV4D/ITVtotal 0.78 vs. ITVs/ITVtotal 0.63), and larger ITVs (19.9 cc vs. 16.3 cc) than those obtained with CTs. Planning with 4D PET/CT in comparison with CTs, allows incorporating tumor respiratory motion and improving planning radiotherapy of patients in early stages of lung cancer. Copyright © 2016 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

  10. The CCTC Quick-Reacting General War Gaming System (QUICK) Program Maintenance Manual. Volume II. Weapon/Target Identification Subsystem. Change 1.

    DTIC Science & Technology

    1978-11-01

    should be used sparingly. If a match is found OMITTING will cause a return to SELECT while REPLACING will delete the old record. Now that the masters for...subroutine included under DBMOD. DESTAB keeps track of the number of target records within the data base , the number of tar - get records deleted , and...considered by the allocator are deleted . Also SORTIT is called and the FLAG-DESIG Listing and Target Designator-Number Directory are printed

  11. Oscillatory Chloride Efflux at the Pollen Tube Apex Has a Role in Growth and Cell Volume Regulation and Is Targeted by Inositol 3,4,5,6-Tetrakisphosphate

    PubMed Central

    Zonia, Laura; Cordeiro, Sofia; Tupý, Jaroslav; Feijó, José A.

    2002-01-01

    Oscillatory growth of pollen tubes has been correlated with oscillatory influxes of the cations Ca2+, H+, and K+. Using an ion-specific vibrating probe, a new circuit was identified that involves oscillatory efflux of the anion Cl− at the apex and steady influx along the tube starting at 12 μm distal to the tip. This spatial coupling of influx and efflux sites predicts that a vectorial flux of Cl− ion traverses the apical region. The Cl− channel blockers 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (DIDS) and 5-nitro-2-(3-phenylpropylamino)benzoic acid completely inhibited tobacco pollen tube growth at 80 and 20 μM, respectively. Cl− channel blockers also induced increases in apical cell volume. The apical 50 μm of untreated pollen tubes had a mean cell volume of 3905 ± 75 μm3. DIDS at 80 μM caused a rapid and lethal cell volume increase to 6206 ± 171 μm3, which is at the point of cell bursting at the apex. DIDS was further demonstrated to disrupt Cl− efflux from the apex, indicating that Cl− flux correlates with pollen tube growth and cell volume status. The signal encoded by inositol 3,4,5,6-tetrakisphosphate [Ins(3,4,5,6)P4] antagonized pollen tube growth, induced cell volume increases, and disrupted Cl− efflux. Ins(3,4,5,6)P4 decreased the mean growth rate by 85%, increased the cell volume to 5997 ± 148 μm3, and disrupted normal Cl− efflux oscillations. These effects were specific for Ins(3,4,5,6)P4 and were not mimicked by either Ins(1,3,4,5)P4 or Ins(1,3,4,5,6)P5. Growth correlation analysis demonstrated that cycles of Cl− efflux were coupled to and temporally in phase with cycles of growth. A role for Cl− flux in the dynamic cellular events during growth is assessed. Differential interference contrast microscopy and kymographic analysis of individual growth cycles revealed that vesicles can advance transiently to within 2 to 4 μm of the apex during the phase of maximally increasing Cl− efflux, which temporally

  12. Costs and benefits of industrial reporting and voluntary targets for energy efficiency. A report to the Congress of the United States. Volume I: Main report

    SciTech Connect

    Not Available

    1994-02-01

    Section 131(c) of the Energy Policy Act of 1992 (EPACT) (Public Law 102-486) requires the Department of Energy (DOE) to evaluate the costs and benefits of federally mandated energy efficiency reporting requirements and voluntary energy efficiency improvement targets for energy-intensive industries. It also requires DOE to evaluate the role of reporting and targets in improving energy efficiency. Specifically, the legislation states: Not later than one year after the data of the enactment of this Act, the Secretary shall, in consultation with affected industries, evaluate and report to the Congress regarding the establishment of Federally mandated energy efficiency reporting requirements and voluntary energy efficiency improvement targets for energy intensive industries. Such report shall include an evaluation of the costs and benefits of such reporting requirements and voluntary energy efficiency improvement targets, and recommendations regarding the role of such activities in improving energy efficiency in energy intensive industries. This report is DOE`s response to that directive. It is the culmination of a year-long study that included (1) analysis of documents pertaining to a previous reporting and targets effort, the industrial Energy Efficiency Improvements Program (or the CE-189 program, following the designation of the reporting form used to collect data in that program), administered by DOE from 1976 to 1985, as well as other important background information; (2) extensive consultations with government and industry officials regarding the CE-189 Program, experience with other programs that have reporting elements, and the attributes of possible alternative strategies for reporting and targets; and (3) analyses of the costs and benefits of the CE-189 Program and several alternatives to the CE-189 approach.

  13. Costs and benefits of industrial reporting and voluntary targets for energy efficiency. A report to the Congress of the United States. Volume II: Appendices

    SciTech Connect

    Not Available

    1994-02-01

    This part sets forth the regulations for the Industrial Energy conservation Program established under Part E of Title III of the Act. It includes criteria and procedures for the identification of reporting corporations, reporting requirements, criteria and procedures for exemption from filing reports directly with DOE, voluntary industrial energy efficiency improvement targets and voluntary recovered materials utilization targets. The purpose of the program is to promote increased energy conservation by American industry and, as it relates to the use of recovered materials, to conserve valuable energy and scarce natural resources.

  14. State and Local Implementation of the No Child Left Behind Act. Volume VI--Targeting and Uses of Federal Education Funds

    ERIC Educational Resources Information Center

    Chambers, Jay G.; Lam, Irene; Mahitivanichcha, Kanya; Esra, Phil; Shambaugh, Larisa; Stullich, Stephanie

    2009-01-01

    Achieving the goals of federal education legislation depends on how federal funds are distributed and used. Since the enactment of the Elementary and Secondary Education Act (ESEA) in 1965, various federal programs have been created to support educational improvement and target additional resources to meet the educational needs of children who are…

  15. A highly detailed FEM volume conductor model based on the ICBM152 average head template for EEG source imaging and TCS targeting.

    PubMed

    Haufe, Stefan; Huang, Yu; Parra, Lucas C

    2015-08-01

    In electroencephalographic (EEG) source imaging as well as in transcranial current stimulation (TCS), it is common to model the head using either three-shell boundary element (BEM) or more accurate finite element (FEM) volume conductor models. Since building FEMs is computationally demanding and labor intensive, they are often extensively reused as templates even for subjects with mismatching anatomies. BEMs can in principle be used to efficiently build individual volume conductor models; however, the limiting factor for such individualization are the high acquisition costs of structural magnetic resonance images. Here, we build a highly detailed (0.5mm(3) resolution, 6 tissue type segmentation, 231 electrodes) FEM based on the ICBM152 template, a nonlinear average of 152 adult human heads, which we call ICBM-NY. We show that, through more realistic electrical modeling, our model is similarly accurate as individual BEMs. Moreover, through using an unbiased population average, our model is also more accurate than FEMs built from mismatching individual anatomies. Our model is made available in Matlab format.

  16. A mathematical approach towards simulating a realistic tissue activity curve of 64Cu-ATSM for the purpose of sub-target volume delineation in radiotherapy

    NASA Astrophysics Data System (ADS)

    Dalah, E.; Bradley, D.; Nisbet, A.

    2010-07-01

    One unique feature of positron emission tomography (PET) is that it allows measurements of regional tracer concentration in hypoxic tumour-bearing tissue, supporting the need for accurate radiotherapy treatment planning. Generally the data are taken over multiple time frames, in the form of tissue activity curves (TACs), providing an indication of the presence of hypoxia, the degree of oxygen perfusion, vascular geometry and hypoxia fraction. In order to understand such a complicated phenomenon a number of theoretical studies have attempted to describe tracer uptake in tissue cells. More recently, a novel computerized reaction diffusion equation method developed by Kelly and Brady has allowed simulation of the realistic TACs of 18F-FMISO, with representation of physiological oxygen heterogeneity and tracer kinetics. We present a refinement to the work of Kelly and Brady, with a particular interest in simulating TACs of the most promising hypoxia selective tracer, 64Cu-ATSM, demonstrating its potential role in tumour sub-volume delineation for radiotherapy treatment planning. Simulation results have demonstrated the high contrast of imaging using ATSM, with a tumour to blood ratio ranging 2.24-4.1. Similarly, results of tumour sub-volumes generated using three different thresholding methods were all well correlated.

  17. Study for identification of beneficial Uses of Space (BUS). Volume 2: Technical report. Book 3: Development and business analysis of space processed tungsten fox X-ray targets

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The development plans, analysis of required R and D and production resources, the costs of such resources, and finally, the potential profitability of a commercial space processing opportunity for containerless melting and resolidification of tungsten are discussed. The aim is to obtain a form of tungsten which, when fabricated into targets for X-ray tubes, provides at least, a 50 percent increase in service life.

  18. Significant Reduction of Late Toxicities in Patients With Extremity Sarcoma Treated With Image-Guided Radiation Therapy to a Reduced Target Volume: Results of Radiation Therapy Oncology Group RTOG-0630 Trial

    PubMed Central

    Wang, Dian; Zhang, Qiang; Eisenberg, Burton L.; Kane, John M.; Li, X. Allen; Lucas, David; Petersen, Ivy A.; DeLaney, Thomas F.; Freeman, Carolyn R.; Finkelstein, Steven E.; Hitchcock, Ying J.; Bedi, Manpreet; Singh, Anurag K.; Dundas, George; Kirsch, David G.

    2015-01-01

    Purpose We performed a multi-institutional prospective phase II trial to assess late toxicities in patients with extremity soft tissue sarcoma (STS) treated with preoperative image-guided radiation therapy (IGRT) to a reduced target volume. Patients and Methods Patients with extremity STS received IGRT with (cohort A) or without (cohort B) chemotherapy followed by limb-sparing resection. Daily pretreatment images were coregistered with digitally reconstructed radiographs so that the patient position could be adjusted before each treatment. All patients received IGRT to reduced tumor volumes according to strict protocol guidelines. Late toxicities were assessed at 2 years. Results In all, 98 patients were accrued (cohort A, 12; cohort B, 86). Cohort A was closed prematurely because of poor accrual and is not reported. Seventy-nine eligible patients from cohort B form the basis of this report. At a median follow-up of 3.6 years, five patients did not have surgery because of disease progression. There were five local treatment failures, all of which were in field. Of the 57 patients assessed for late toxicities at 2 years, 10.5% experienced at least one grade ≥ 2 toxicity as compared with 37% of patients in the National Cancer Institute of Canada SR2 (CAN-NCIC-SR2: Phase III Randomized Study of Pre- vs Postoperative Radiotherapy in Curable Extremity Soft Tissue Sarcoma) trial receiving preoperative radiation therapy without IGRT (P < .001). Conclusion The significant reduction of late toxicities in patients with extremity STS who were treated with preoperative IGRT and absence of marginal-field recurrences suggest that the target volumes used in the Radiation Therapy Oncology Group RTOG-0630 (A Phase II Trial of Image-Guided Preoperative Radiotherapy for Primary Soft Tissue Sarcomas of the Extremity) study are appropriate for preoperative IGRT for extremity STS. PMID:25667281

  19. Variations in CT determination of target volume with active breath co-ordinate in radiotherapy for post-operative gastric cancer

    PubMed Central

    Li, Gui-Chao; Ma, Xue-Jun; Yu, Xiao-Li; Hu, Wei-Gang; Wang, Jia-Zhou; Li, Qi-Wen; Liang, Li-Ping; Shen, Li-Jun; Zhang, Hui; Fan, Ming

    2016-01-01

    Objective: To investigate interobserver and inter-CT variations in using the active breath co-ordinate technique in the determination of clinical tumour volume (CTV) and normal organs in post-operative gastric cancer radiotherapy. Methods: Ten gastric cancer patients were enrolled in our study, and four radiation oncologists independently determined the CTVs and organs at risk based on the CT simulation data. To determine interobserver and inter-CT variation, we evaluated the maximum dimensions, derived volume and distance between the centres of mass (CMs) of the CTVs. We assessed the reliability in CTV determination among the observers by conformity index (CI). Results: The average volumes ± standard deviation (cm3) of the CTV, liver, left kidney and right kidney were 674 ± 138 (range, 332–969), 1000 ± 138 (range, 714–1320), 149 ± 13 (range, 104–183) and 141 ± 21 (range, 110–186) cm3, respectively. The average inter-CT distances between the CMs of the CTV, liver, left kidney and right kidney were 0.40, 0.56, 0.65 and 0.6 cm, respectively; the interobserver values were 0.98, 0.53, 0.16 and 0.15 cm, respectively. Conclusions: In the volume size of CTV for post-operative gastric cancer, there were significant variations among multiple observers, whereas there was no variation between different CTs. The slices in which variations more likely occur were the slices of the lower verge of the hilum of the spleen and porta hepatis, then the paraoesophageal lymph nodes region and abdominal aorta, and the inferior vena cava, and the variation in the craniocaudal orientation from the interobserver was more predominant than that from inter-CT. Advances in knowledge: First, this is the first study to evaluate the interobserver and inter-CT variations in the determination of the CTV and normal organs in gastric cancer with the use of the active breath co-ordinate technique. Second, we analysed the region where variations most likely occur

  20. Time to achieve target mean arterial pressure during resuscitation from experimental anaphylactic shock in an animal model. A comparison of adrenaline alone or in combination with different volume expanders.

    PubMed

    Tajima, K; Zheng, F; Collange, O; Barthel, G; Thornton, S N; Longrois, D; Levy, B; Audibert, G; Malinovsky, J M; Mertes, P M

    2013-11-01

    Anaphylactic shock is a rare, but potentially lethal complication, combining life-threatening circulatory failure and massive fluid shifts. Treatment guidelines rely on adrenaline and volume expansion by intravenous fluids, but there is no solid evidence for the choice of one specific type of fluid over another. Our purpose was to compare the time to achieve target mean arterial pressure upon resuscitation using adrenaline alone versus adrenaline with different resuscitation fluids in an animal model and to compare the tissue oxygen pressures (PtiO2) with the various strategies. Twenty-five ovalbumin-sensitised Brown Norway rats were allocated to five groups after anaphylactic shock induction: vehicle (CON), adrenaline alone (AD), or adrenaline with isotonic saline (AD+IS), hydroxyethyl starch (AD+HES) or hypertonic saline (AD+HS). Time to reach a target mean arterial pressure value of 75 mmHg, cardiac output, skeletal muscle PtiO2, lactate/pyruvate ratio and cumulative doses of adrenaline were recorded. Non-treated rats died within 15 minutes. The target mean arterial pressure value was reached faster with AD+HES (median: 10 minutes, range: 7.5 to 12.5 minutes) and AD+IS (median: 17.5 minutes, range: 5 to 25 minutes) versus adrenaline alone (median: 25 minutes, range: 20-30 minutes). There were also reduced adrenaline requirements in these groups. The skeletal muscle PtiO2 was restored only in the AD+HES group. Although direct extrapolation to humans should be made with caution, our results support the combined use of adrenaline and volume expansion for resuscitation from anaphylactic shock. When used with adrenaline the most effective fluid was hydroxyethyl starch, whereas hypertonic saline was the least effective.

  1. Hypervelocity Impact (HVI). Volume 2; WLE Small-Scale Fiberglass Panel Flat Multi-Layer Targets A-1, A-2, and B-1

    NASA Technical Reports Server (NTRS)

    Gorman, Michael R.; Ziola, Steven M.

    2007-01-01

    During 2003 and 2004, the Johnson Space Center's White Sands Testing Facility in Las Cruces, New Mexico conducted hypervelocity impact tests on the space shuttle wing leading edge. Hypervelocity impact tests were conducted to determine if Micro-Meteoroid/Orbital Debris impacts could be reliably detected and located using simple passive ultrasonic methods. The objective of Targets A-1, A-2, and B-2 was to study hypervelocity impacts through multi-layered panels simulating Whipple shields on spacecraft. Impact damage was detected using lightweight, low power instrumentation capable of being used in flight.

  2. {sup 18}F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography-Based Radiotherapy Target Volume Definition in Non-Small-Cell Lung Cancer: Delineation by Radiation Oncologists vs. Joint Outlining With a PET Radiologist?

    SciTech Connect

    Hanna, Gerard G.; Carson, Kathryn J.; Lynch, Tom; McAleese, Jonathan; Cosgrove, Vivian P.; Eakin, Ruth L.; Stewart, David P.; Zatari, Ashraf; O'Sullivan, Joe M.; Hounsell, Alan R.

    2010-11-15

    Purpose: {sup 18}F-Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) has benefits in target volume (TV) definition in radiotherapy treatment planning (RTP) for non-small-cell lung cancer (NSCLC); however, an optimal protocol for TV delineation has not been determined. We investigate volumetric and positional variation in gross tumor volume (GTV) delineation using a planning PET/CT among three radiation oncologists and a PET radiologist. Methods and Materials: RTP PET/CT scans were performed on 28 NSCLC patients (Stage IA-IIIB) of which 14 patients received prior induction chemotherapy. Three radiation oncologists and one PET radiologist working with a fourth radiation oncologist independently delineated the GTV on CT alone (GTV{sub CT}) and on fused PET/CT images (GTV{sub PETCT}). The mean percentage volume change (PVC) between GTV{sub CT} and GTV{sub PETCT} for the radiation oncologists and the PVC between GTV{sub CT} and GTV{sub PETCT} for the PET radiologist were compared using the Wilcoxon signed-rank test. Concordance index (CI) was used to assess both positional and volume change between GTV{sub CT} and GTV{sub PETCT} in a single measurement. Results: For all patients, a significant difference in PVC from GTV{sub CT} to GTV{sub PETCT} exists between the radiation oncologist (median, 5.9%), and the PET radiologist (median, -0.4%, p = 0.001). However, no significant difference in median concordance index (comparing GTV{sub CT} and GTV{sub FUSED} for individual cases) was observed (PET radiologist = 0.73; radiation oncologists = 0.66; p = 0.088). Conclusions: Percentage volume changes from GTV{sub CT} to GTV{sub PETCT} were lower for the PET radiologist than for the radiation oncologists, suggesting a lower impact of PET/CT in TV delineation for the PET radiologist than for the oncologists. Guidelines are needed to standardize the use of PET/CT for TV delineation in RTP.

  3. SU-E-T-147: Beam Specific Planning Target Volumes Incorporating 4DCT for Pencil Beam Scanning Proton Therapy of Thoracic Tumors

    SciTech Connect

    Lin, L; Kang, M; Huang, S; McDonough, J; Solberg, T; Simone, C; Mayer, R; Thomas, A

    2015-06-15

    Purpose: The purpose of this study is to determine whether organ sparing and target coverage can be simultaneously maintained for pencil beam scanning (PBS) proton therapy treatment of thoracic tumors in the presence of motion, stopping power uncertainties and patient setup variations. Methods: Ten consecutive patients that were previously treated with proton therapy to 66.6/1.8 Gy (RBE) using double scattering (DS) were replanned with PBS. Minimum and maximum intensity images from 4DCT were used to introduce flexible smearing in the determination of the beam specific PTV (BSPTV). Datasets from eight 4DCT phases, using ±3% uncertainty in stopping power, and ±3 mm uncertainty in patient setup in each direction were used to create 8*12*10=960 PBS plans for the evaluation of ten patients. Plans were normalized to provide identical coverage between DS and PBS. Results: The average lung V20, V5, and mean doses were reduced from 29.0%, 35.0%, and 16.4 Gy with DS to 24.6%, 30.6%, and 14.1 Gy with PBS, respectively. The average heart V30 and V45 were reduced from 10.4% and 7.5% in DS to 8.1% and 5.4% for PBS, respectively. Furthermore, the maximum spinal cord, esophagus and heart dose were decreased from 37.1 Gy, 71.7 Gy and 69.2 Gy with DS to 31.3 Gy, 67.9 Gy and 64.6 Gy with PBS. The conformity index (CI), homogeneity index (HI), and global maximal dose were improved from 3.2, 0.08, 77.4 Gy with DS to 2.8, 0.04 and 72.1 Gy with PBS. All differences are statistically significant, with p values <0.05, with the exception of the heart V45 (p= 0.146). Conclusion: PBS with BSPTV achieves better organ sparing and improves target coverage using a repainting method for the treatment of thoracic tumors. Incorporating motion-related uncertainties is essential This work was supported by the US Army Medical Research and Materiel Command under Contract Agreement No. DAMD17-W81XWH-07-2-0121 and W81XWH-09-2-0174.

  4. Hippocampal-sparing and target volume coverage in treating 3 to 10 brain metastases: A comparison of Gamma Knife, single-isocenter VMAT, CyberKnife, and TomoTherapy stereotactic radiosurgery.

    PubMed

    Zhang, Isabella; Antone, Jeff; Li, Jenny; Saha, Shyamali; Riegel, Adam C; Vijeh, Lili; Lauritano, Joe; Marrero, Mihaela; Salas, Sussan; Schulder, Michael; Zinkin, Heather; Goenka, Anuj; Knisely, Jonathan

    Our purpose was to evaluate hippocampal doses and target volume coverage with and without hippocampal sparing when treating multiple brain metastases using various stereotactic radiosurgery (SRS) platforms. We selected 10 consecutive patients with 14 separate treatments who had been treated in our department for 3 to 10 brain metastases and added hippocampal avoidance contours. All 14 treatments were planned with GammaPlan for Gamma Knife, Eclipse for single isocenter volumetric modulated arc therapy (VMAT), TomoTherapy Treatment Planning System (TPS) for TomoTherapy, and MultiPlan for CyberKnife. Initial planning was performed with the goal of planning target volume coverage of V100 ≥95% without hippocampal avoidance. If the maximum hippocampal point dose (Dmax) was <6.6 Gy in a single fraction and <40% of the hippocampi received ≤4.5 Gy, no second plan was performed. If either constraint was not met, replanning was performed with these constraints. There was a median of 6 metastases per plan, with an average total tumor volume of 7.32 mL per plan. The median hippocampal Dmax (in Gy) without sparing averaged 1.65, 9.81, 4.38, and 5.46, respectively (P < .0001). Of 14 plans, 3 Gamma Knife and CyberKnife plans required replanning, whereas 13 VMAT and 8 TomoTherapy plans required replanning. The hippocampal constraints were not achievable in 1 plan on any platform when the tumor was bordering the hippocampus. The mean volume of brain receiving 12 Gy (in mL), which has been associated with symptomatic radionecrosis, was 23.57 with Gamma Knife, 76.77 with VMAT, 40.86 with CyberKnife, and 104.06 with TomoTherapy (P = .01). The overall average conformity indices for all plans ranged from 0.36 to 0.52. Even with SRS, the hippocampi can receive a considerable dose; however, if the hippocampi are outlined as organs of risk, sparing these structures is feasible in nearly all situations with all 4 platforms, without detriment to target coverage, and should be considered

  5. Magnetic Resonance Imaging Appearances in the Postoperative Breast: The Clinical Target Volume-Tumor and Its Relationship to the Chest Wall

    SciTech Connect

    Whipp, Elisabeth C. Halliwell, Michael

    2008-09-01

    Purpose: To describe and measure the postoperative complexes and their relationship to the chest wall in 100 randomly chosen MRI breast scans, to attempt a better understanding of the changes taking place in the postoperative breast. Methods and Materials: Appearances and measurements of MRI postoperative cavities were analyzed in a cohort of 100 randomly selected patients who underwent a single open MRI scan in the conventional breast radiotherapy treatment position before routine two-dimensional simulation. Results: Magnetic resonance imaging appearances of postoperative cavities seem to differ qualitatively from descriptions of CT and ultrasound cavities in the literature. Rather than being principally homogeneous, heterogeneous cavities were seen in 85%, irregular in 51%. The size of cavity was inversely related to the time elapsed since surgery. Cavities directly touched the chest wall in 53% of cases; 89% lay within 10 mm of the chest wall. Regular, annular concentric rings of differing signal were seen in 32% of cases; such appearances have not been previously described. These patterns suggest that seromas may not shrink entirely as a result of simple serous fluid absorption; instead, new tissue may be being laid down. Because large, regular spheroidal/ellipsoidal cavities with crisp margins may be seromas under pressure, greater target shifts during radiation may need to be anticipated in such cases. Conclusions: Postsurgical cavities in the conserved breast on MRI are commonly heterogeneous, irregular, and lie close to the chest wall. Magnetic resonance imaging studies may help in better understanding the natural history of postoperative cavities.

  6. Image-Guided Radiation Therapy for Muscle-Invasive Carcinoma of the Urinary Bladder with Cone Beam CT Scan: Use of Individualized Internal Target Volumes for a Single Patient.

    PubMed

    Saini, Gagan; Aggarwal, Anchal; Srivastava, Roopam; Sharma, Pramod K; Garg, Madhur; Nangia, Sapna; Chomal, Manish

    2012-09-01

    While planning radiation therapy (RT) for a carcinoma of the urinary bladder (CaUB), the intra-fractional variation of the urinary bladder (UB) volume due to filling-up needs to be accounted for. This internal target volume (ITV) is obtained by adding internal margins (IM) to the contoured bladder. This study was planned to propose a method of acquiring individualized ITVs for each patient and to verify their reproducibility. One patient with CaUB underwent simulation with the proposed 'bladder protocol'. After immobilization, a planning CT scan on empty bladder was done. He was then given 300 ml of water to drink and the time (T) was noted. Planning CT scans were performed after 20 min (T+20), 30 min (T+30) and 40 min (T+40). The CT scan at T+20 was co-registered with the T+30 and T+40 scans. The bladder volumes at 20, 30 and 40 min were then contoured as CTV20, CTV30 and CTV40 to obtain an individualized ITV for our patient. For daily treatment, he was instructed to drink water as above, and the time was noted; treatment was started after 20 min. Daily pre- and post-treatment cone beam CT (CBCT) scans were done. The bladder visualized on the pre-treatment CBCT scan was compared with CTV20 and on the post-treatment CBCT scan with CTV30. In total, there were 65 CBCT scans (36 pre- and 29 post-treatment). Individualized ITVs were found to be reproducible in 93.85% of all instances and fell outside in 4 instances. The proposed bladder protocol can yield a reproducible estimation of the ITV during treatment; this can obviate the need for taking standard IMs.

  7. Volumetric-modulated arc therapy for left-sided breast cancer and all regional nodes improves target volumes coverage and reduces treatment time and doses to the heart and left coronary artery, compared with a field-in-field technique

    PubMed Central

    Tyran, Marguerite; Mailleux, Hugues; Tallet, Agnes; Fau, Pierre; Gonzague, Laurence; Minsat, Mathieu; Moureau-Zabotto, Laurence; Resbeut, Michel

    2015-01-01

    We compared two intensity-modulated radiotherapy techniques for left-sided breast treatment, involving lymph node irradiation including the internal mammary chain. Inverse planned arc-therapy (VMAT) was compared with a forward-planned multi-segment technique with a mono-isocenter (MONOISO). Ten files were planned per technique, delivering a 50-Gy dose to the breast and 46.95 Gy to nodes, within 25 fractions. Comparative endpoints were planning target volume (PTV) coverage, dose to surrounding structures, and treatment delivery time. PTV coverage, homogeneity and conformality were better for two arc VMAT plans; V95%PTV-T was 96% for VMAT vs 89.2% for MONOISO. Homogeneity index (HI)PTV-T was 0.1 and HIPTV-N was 0.1 for VMAT vs 0.6 and 0.5 for MONOISO. Treatment delivery time was reduced by a factor of two using VMAT relative to MONOISO (84 s vs 180 s). High doses to organs at risk were reduced (V30left lung = 14% using VMAT vs 24.4% with MONOISO; dose to 2% of the volume (D2%)heart = 26.1 Gy vs 32 Gy), especially to the left coronary artery (LCA) (D2%LCA = 34.4 Gy vs 40.3 Gy). However, VMAT delivered low doses to a larger volume, including contralateral organs (mean dose [Dmean]right lung = 4 Gy and Dmeanright breast = 3.2 Gy). These were better protected using MONOISO plans (Dmeanright lung = 0.8 Gy and Dmeanright breast = 0.4 Gy). VMAT improved PTV coverage and dose homogeneity, but clinical benefits remain unclear. Decreased dose exposure to the LCA may be clinically relevant. VMAT could be used for complex treatments that are difficult with conventional techniques. Patient age should be considered because of uncertainties concerning secondary malignancies. PMID:26386255

  8. Stereotactic Body Radiotherapy for Primary Lung Cancer at a Dose of 50 Gy Total in Five Fractions to the Periphery of the Planning Target Volume Calculated Using a Superposition Algorithm

    SciTech Connect

    Takeda, Atsuya; Sanuki, Naoko; Kunieda, Etsuo Ohashi, Toshio; Oku, Yohei; Takeda, Toshiaki; Shigematsu, Naoyuki; Kubo, Atsushi

    2009-02-01

    Purpose: To retrospectively analyze the clinical outcomes of stereotactic body radiotherapy (SBRT) for patients with Stages 1A and 1B non-small-cell lung cancer. Methods and Materials: We reviewed the records of patients with non-small-cell lung cancer treated with curative intent between Dec 2001 and May 2007. All patients had histopathologically or cytologically confirmed disease, increased levels of tumor markers, and/or positive findings on fluorodeoxyglucose positron emission tomography. Staging studies identified their disease as Stage 1A or 1B. Performance status was 2 or less according to World Health Organization guidelines in all cases. The prescribed dose of 50 Gy total in five fractions, calculated by using a superposition algorithm, was defined for the periphery of the planning target volume. Results: One hundred twenty-one patients underwent SBRT during the study period, and 63 were eligible for this analysis. Thirty-eight patients had Stage 1A (T1N0M0) and 25 had Stage 1B (T2N0M0). Forty-nine patients were not appropriate candidates for surgery because of chronic pulmonary disease. Median follow-up of these 49 patients was 31 months (range, 10-72 months). The 3-year local control, disease-free, and overall survival rates in patients with Stages 1A and 1B were 93% and 96% (p = 0.86), 76% and 77% (p = 0.83), and 90% and 63% (p = 0.09), respectively. No acute toxicity was observed. Grade 2 or higher radiation pneumonitis was experienced by 3 patients, and 1 of them had fatal bacterial pneumonia. Conclusions: The SBRT at 50 Gy total in five fractions to the periphery of the planning target volume calculated by using a superposition algorithm is feasible. High local control rates were achieved for both T2 and T1 tumors.

  9. Evaluation of the Planning Target Volume in the Treatment of Head and Neck Cancer With Intensity-Modulated Radiotherapy: What Is the Appropriate Expansion Margin in the Setting of Daily Image Guidance?

    SciTech Connect

    Chen, Allen M.; Farwell, D. Gregory; Luu, Quang; Donald, Paul J.; Perks, Julian; Purdy, James A.

    2011-11-15

    Purpose: To compare patterns of disease failure among patients treated with intensity-modulated radiotherapy (IMRT) in conjunction with daily image-guided radiotherapy (IGRT) for head and neck cancer, according to the margins used to expand the clinical target volume (CTV) to create a planning target volume (PTV). Methods and Materials: Two-hundred and twenty-five patients were treated with IMRT for squamous cell carcinoma of the head and neck. Daily IGRT scans were acquired using either kilovoltage or megavoltage volumetric imaging prior to each delivered fraction. The first 95 patients were treated with IMRT with 5-mm CTV-to-PTV margins. The subsequent 130 patients were treated using 3-mm PTV expansion margins. Results: Two-year estimates of overall survival, local-regional control, and distant metastasis-free survival were 76%, 78%, and 81%, respectively. There were no differences with respect to any of these endpoints among patients treated with 5-mm and 3-mm PTV expansion margins (p > 0.05, all). The 2-year local-regional control rate for patients treated with IMRT with 5-mm and 3-mm PTV margins was 78% and 78%, respectively (p = 0.96). Spatial evaluation revealed no differences in the incidences of marginal failures among those treated with 5-mm and 3-mm PTV margins. Conclusions: The use of 3-mm PTV expansion margins appears adequate and did not increase local-regional failures among patients treated with IMRT for head and neck cancer. These data demonstrate the safety of PTV reduction of less than 5 mm and support current protocols recommending this approach in the setting of daily IGRT.

  10. Clinical Validation of Atlas-Based Auto-Segmentation of Multiple Target Volumes and Normal Tissue (Swallowing/Mastication) Structures in the Head and Neck

    SciTech Connect

    Teguh, David N.; Levendag, Peter C.; Voet, Peter W.J.; Al-Mamgani, Abrahim; Han Xiao; Wolf, Theresa K.; Hibbard, Lyndon S.; Nowak, Peter; Akhiat, Hafid; Dirkx, Maarten L.P.; Heijmen, Ben J.M.; Hoogeman, Mischa S.

    2011-11-15

    : Multiple-subject ABAS of computed tomography images proved to be a useful novel tool in the rapid delineation of target and normal tissues. Although editing of the autocontours is inevitable, a substantial time reduction was achieved using editing, instead of manual contouring (180 vs. 66 min).

  11. Proteomic and transcriptomic analysis of heart failure due to volume overload in a rat aorto-caval fistula model provides support for new potential therapeutic targets - monoamine oxidase A and transglutaminase 2

    PubMed Central

    2011-01-01

    Background Chronic hemodynamic overloading leads to heart failure (HF) due to incompletely understood mechanisms. To gain deeper insight into the molecular pathophysiology of volume overload-induced HF and to identify potential markers and targets for novel therapies, we performed proteomic and mRNA expression analysis comparing myocardium from Wistar rats with HF induced by a chronic aorto-caval fistula (ACF) and sham-operated rats harvested at the advanced, decompensated stage of HF. Methods We analyzed control and failing myocardium employing iTRAQ labeling, two-dimensional peptide separation combining peptide IEF and nano-HPLC with MALDI-MS/MS. For the transcriptomic analysis we employed Illumina RatRef-12v1 Expression BeadChip. Results In the proteomic analysis we identified 2030 myocardial proteins, of which 66 proteins were differentially expressed. The mRNA expression analysis identified 851 differentially expressed mRNAs. Conclusions The differentially expressed proteins confirm a switch in the substrate preference from fatty acids to other sources in the failing heart. Failing hearts showed downregulation of the major calcium transporters SERCA2 and ryanodine receptor 2 and altered expression of creatine kinases. Decreased expression of two NADPH producing proteins suggests a decreased redox reserve. Overexpression of annexins supports their possible potential as HF biomarkers. Most importantly, among the most up-regulated proteins in ACF hearts were monoamine oxidase A and transglutaminase 2 that are both potential attractive targets of low molecular weight inhibitors in future HF therapy. PMID:22078724

  12. New method for rapid solid-phase extraction of large-volume water samples and its application to non-target screening of North Sea water for organic contaminants by gas chromatography-mass spectrometry.

    PubMed

    Weigel, S; Bester, K; Hühnerfuss, H

    2001-03-30

    A method has been developed that allows the solid-phase extraction of microorganic compounds from large volumes of water (10 l) for non-target analysis of filtered seawater. The filtration-extraction system is operated with glass fibre filter candles and the polymeric styrene-divinylbenzene sorbent SDB-1 at flow-rates as high as 500 ml/min. Recovery studies carried out for a couple of model substances covering a wide range of polarity and chemical classes revealed a good performance of the method. Especially for polar compounds (log Kow 3.3-0.7) quantitative recovery was achieved. Limits of detection were between 0.1 and 0.7 ng/l in the full scan mode of the MS. The suitability of the method for the analysis of marine water samples is demonstrated by the non-target screening of water from the German Bight for the presence of organic contaminants. In the course of this screening a large variety of substances was identified including pesticides, industrial chemicals and pharmaceuticals. For some of the identified compounds their occurrence in marine ecosystems has not been reported before, such as dichloropyridines, carbamazepine, propyphenazone and caffeine.

  13. Time-Adjusted Internal Target Volume: A Novel Approach Focusing on Heterogeneity of Tumor Motion Based on 4-Dimensional Computed Tomography Imaging for Radiation Therapy Planning of Lung Cancer

    SciTech Connect

    Nishibuchi, Ikuno; Kimura, Tomoki; Nakashima, Takeo; Ochi, Yusuke; Takahashi, Ippei; Doi, Yoshiko; Kenjo, Masahiro; Kaneyasu, Yuko; Ozawa, Syuichi; Murakami, Yuji; Wadasaki, Koichi; Nagata, Yasushi

    2014-08-01

    Purpose: To consider nonuniform tumor motion within the internal target volume (ITV) by defining time-adjusted ITV (TTV), a volume designed to include heterogeneity of tumor existence on the basis of 4-dimensional computed tomography (4D-CT). Methods and Materials: We evaluated 30 lung cancer patients. Breath-hold CT (BH-CT) and free-breathing 4D-CT scans were acquired for each patient. The tumors were manually delineated using a lung CT window setting (window, 1600 HU; level, −300 HU). Tumor in BH-CT images was defined as gross tumor volume (GTV), and the sum of tumors in 4D-CT images was defined as ITV-4D. The TTV images were generated from the 4D-CT datasets, and the tumor existence probability within ITV-4D was calculated. We calculated the TTV{sub 80} value, which is the percentage of the volume with a tumor existence probability that exceeded 80% on ITV-4D. Several factors that affected the TTV{sub 80} value, such as the ITV-4D/GTV ratio or tumor centroid deviation, were evaluated. Results: Time-adjusted ITV images were acquired for all patients, and tumor respiratory motion heterogeneity was visualized. The median (range) ITV-4D/GTV ratio and median tumor centroid deviation were 1.6 (1.0-4.1) and 6.3 mm (0.1-30.3 mm), respectively. The median TTV{sub 80} value was 43.3% (2.9-98.7%). Strong correlations were observed between the TTV{sub 80} value and the ITV-4D/GTV ratio (R=−0.71) and tumor centroid deviation (R=−0.72). The TTV images revealed the tumor motion pattern features within ITV. Conclusions: The TTV images reflected nonuniform tumor motion, and they revealed the tumor motion pattern features, suggesting that the TTV concept may facilitate various aspects of radiation therapy planning of lung cancer while incorporating respiratory motion in the future.

  14. Bar coded retroreflective target

    DOEpatents

    Vann, Charles S.

    2000-01-01

    This small, inexpensive, non-contact laser sensor can detect the location of a retroreflective target in a relatively large volume and up to six degrees of position. The tracker's laser beam is formed into a plane of light which is swept across the space of interest. When the beam illuminates the retroreflector, some of the light returns to the tracker. The intensity, angle, and time of the return beam is measured to calculate the three dimensional location of the target. With three retroreflectors on the target, the locations of three points on the target are measured, enabling the calculation of all six degrees of target position. Until now, devices for three-dimensional tracking of objects in a large volume have been heavy, large, and very expensive. Because of the simplicity and unique characteristics of this tracker, it is capable of three-dimensional tracking of one to several objects in a large volume, yet it is compact, light-weight, and relatively inexpensive. Alternatively, a tracker produces a diverging laser beam which is directed towards a fixed position, and senses when a retroreflective target enters the fixed field of view. An optically bar coded target can be read by the tracker to provide information about the target. The target can be formed of a ball lens with a bar code on one end. As the target moves through the field, the ball lens causes the laser beam to scan across the bar code.

  15. Volumetric-modulated arc therapy for left-sided breast cancer and all regional nodes improves target volumes coverage and reduces treatment time and doses to the heart and left coronary artery, compared with a field-in-field technique.

    PubMed

    Tyran, Marguerite; Mailleux, Hugues; Tallet, Agnes; Fau, Pierre; Gonzague, Laurence; Minsat, Mathieu; Moureau-Zabotto, Laurence; Resbeut, Michel

    2015-11-01

    We compared two intensity-modulated radiotherapy techniques for left-sided breast treatment, involving lymph node irradiation including the internal mammary chain. Inverse planned arc-therapy (VMAT) was compared with a forward-planned multi-segment technique with a mono-isocenter (MONOISO). Ten files were planned per technique, delivering a 50-Gy dose to the breast and 46.95 Gy to nodes, within 25 fractions. Comparative endpoints were planning target volume (PTV) coverage, dose to surrounding structures, and treatment delivery time. PTV coverage, homogeneity and conformality were better for two arc VMAT plans; V95%(PTV-T) was 96% for VMAT vs 89.2% for MONOISO. Homogeneity index (HI)(PTV-T) was 0.1 and HI(PTV-N) was 0.1 for VMAT vs 0.6 and 0.5 for MONOISO. Treatment delivery time was reduced by a factor of two using VMAT relative to MONOISO (84 s vs 180 s). High doses to organs at risk were reduced (V30(left lung) = 14% using VMAT vs 24.4% with MONOISO; dose to 2% of the volume (D2%)(heart) = 26.1 Gy vs 32 Gy), especially to the left coronary artery (LCA) (D2%(LCA) = 34.4 Gy vs 40.3 Gy). However, VMAT delivered low doses to a larger volume, including contralateral organs (mean dose [Dmean](right lung) = 4 Gy and Dmean(right breast) = 3.2 Gy). These were better protected using MONOISO plans (Dmean(right lung) = 0.8 Gy and Dmean(right breast) = 0.4 Gy). VMAT improved PTV coverage and dose homogeneity, but clinical benefits remain unclear. Decreased dose exposure to the LCA may be clinically relevant. VMAT could be used for complex treatments that are difficult with conventional techniques. Patient age should be considered because of uncertainties concerning secondary malignancies. © The Author 2015. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  16. Intensity-modulated salvage radiotherapy with simultaneous integrated boost for local recurrence of prostate carcinoma: a pilot study on the place of PET-choline for guiding target volume delineation

    PubMed Central

    Wahart, Aurélien; Guy, Jean-Baptiste; Vallard, Alexis; Geissler, Benjamin; Ben Mrad, Majed; Falk, Alexander T; Prevot, Nathalie; de Laroche, Guy; Rancoule, Chloé; Chargari, Cyrus

    2016-01-01

    Objective: The aim of this study was to report the first cases of salvage radiotherapy (RT) using the intensity-modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB) targeted on choline positron emission tomography (PET) uptake in a local recurrent prostate cancer, after a radical prostatectomy. Methods: Four patients received salvage irradiation for biochemical relapse that occurred after the initial radical prostatectomy. The relapse occurred from 10 months to 6 years with PSA levels ranging from 2.35 to 4.86 ng ml−1. For each patient, an 18F-choline PET-CT showed a focal choline uptake in prostatic fossa, with standardized uptake value calculated on the basis of predicted lean body mass (SUL) max of 3.3–6.8. No involved lymph node or distant metastases were diagnosed. IMRT doses were of 62.7 Gy (1.9 Gy/fraction, 33 fractions), with a SIB of 69.3 Gy (2.1 Gy/fraction, 33 fractions) to a PET-guided target volume. Results: Acute toxicities were limited. We observed no gastrointestinal toxicity ≥grade 2 and only one grade 2 genitourinary toxicity. At 1-month follow-up evaluation, no complication and a decrease in PSA level (6.8–43.8% of the pre-therapeutic level) were reported. After 4 months, a decrease in PSA level was obtained for all the patients, ranging from 30% to 70%. At a median follow-up of 15 months, PSA level was controlled for all the patients, but one of them experienced a distant lymph node recurrence. Conclusion: Salvage irradiation to the prostate bed with SIB guided by PET-CT is feasible, with biological efficacy and no major acute toxicity. Advances in knowledge: IMRT with PET-oriented SIB for salvage treatment of prostate cancer is possible, without major acute toxicity. PMID:26648528

  17. A Multi-Target Survey. Volume I.

    DTIC Science & Technology

    1979-12-01

    track assignment. In this report, the need for state estimation to identify feasible tracks is ’. eliminated. The use of simpler input-output models ...generally, been based on state-space models and recursive filtering methods. The new aspects of the multitarget tracking problem stem from the necessity for...mathematical model for the problem. Suppose that Mk, fk-1, 2, ---1 measurement vectors zi(tk), =i 1, 2, .-. , k j are obtained at meass- *urement time tk. These

  18. A Multi-Target Survey. Volume II.

    DTIC Science & Technology

    1979-12-01

    clutter and/or measure- feasible frack does not correspond to a best surveillance picture. This men ts from another targt. In order for correct...allocation of data to a is quite easy to do if the tracks overlap and compete for the ame given track to be made. one must have an effective scoring formula...data is. To be effective , a soing formula must produce (on the ave surements to a track. However. once a decision has bo made that a age) a better

  19. [Targeted treatments: which imaging?].

    PubMed

    Lassau, Nathalie; Chebil, Mohamed; Benatsou, Baya; Chami, Linda; Roche, Alain

    2008-10-01

    Currently, the evaluation of targeted treatments by functional imaging in oncology is a main goal. Several techniques as Dynamic Contrast Enhanced-MRI, CT-perfusion or Dynamic Contrast Enhanced-US are proposed. The blood flow perfusing the tumor, the blood volume corresponding to the percentage of vessels of total tumor or the diffusion of contrast agent are parameters calculated from the acquisition of time intensity curves during several minutes (TIC). Blood flow, blood volume and mean transit time could be calculated by DCE-US, DCE-MRI and CT-perfusion. But the capillary permeability and the interstitial volume could be evaluated only with DCE-MRI and CT-perfusion because US contrast agent is strictly intravascular. These functional imaging techniques allow predicting earlier the clinical response to targeted treatments before the modification of tumoral volume evaluated according to RECIST criteria.

  20. Reduction in patient-reported acute morbidity in prostate cancer patients treated with 81-Gy Intensity-modulated radiotherapy using reduced planning target volume margins and electromagnetic tracking: assessing the impact of margin reduction study.

    PubMed

    Sandler, Howard M; Liu, Ping-Yu; Dunn, Rodney L; Khan, David C; Tropper, Scott E; Sanda, Martin G; Mantz, Constantine A

    2010-05-01

    To investigate whether patient-reported quality of life after high-dose external beam intensity-modulated radiotherapy for prostate cancer can be improved by decreasing planning target volume margins while using real-time tumor tracking. Study patients underwent radiotherapy with nominal 3-mm margins and electromagnetic real-time tracking. Morbidity was assessed before and at the end of radiotherapy using Expanded Prostate Cancer Index Composite (EPIC) questionnaires. Changes in scores were compared between the Assessing Impact of Margin Reduction (AIM) study cohort and the comparator Prostate Cancer Outcomes and Satisfaction with Treatment Quality Assessment (PROST-QA) cohort, treated with conventional margins. The 64 patients in the prospective AIM study had generally less favorable clinical characteristics than the 153 comparator patients. Study patients had similar or slightly poorer pretreatment EPIC scores than comparator patients in bowel, urinary, and sexual domains. AIM patients receiving radiotherapy had less bowel morbidity than the comparator group as measured by changes in mean bowel and/or rectal domain EPIC scores from pretreatment to 2 months after start of treatment (-1.5 vs -16.0, P = .001). Using a change in EPIC score >0.5 baseline standard deviation as the measure of clinical relevance, AIM study patients experienced meaningful decline in only 1 health-related quality of life domain (urinary) whereas decline in 3 health-related quality of life domains (urinary, sexual, and bowel/rectal) was observed in the PROST-QA comparator cohort. Prostate cancer patients treated with reduced margins and tumor tracking had less radiotherapy-related morbidity than their counterparts treated with conventional margins. Highly contoured intensity-modulated radiotherapy shows promise as a successful strategy for reducing morbidity in prostate cancer treatment. Copyright 2010 Elsevier Inc. All rights reserved.

  1. Patterns of Local-Regional Failure in Completely Resected Stage IIIA(N2) Non-Small Cell Lung Cancer Cases: Implications for Postoperative Radiation Therapy Clinical Target Volume Design

    SciTech Connect

    Feng, Wen; Fu, Xiao-Long; Cai, Xu-Wei; Yang, Huan-Jun; Wu, Kai-Liang; Fan, Min; Xiang, Jia-Qing; Zhang, Ya-Wei; Chen, Hai-Quan

    2014-04-01

    Purpose: To analyze patterns of local-regional failure (LRF) for completely resected stage IIIA(N2) non-small cell lung cancer (NSCLC) patients treated in our hospital and to propose a clinical target volume (CTV) for postoperative radiation therapy (PORT) in these patients. Methods and Materials: From 2005 to 2011, consecutive patients with pT1-3N2 NSCLC who underwent complete resection in our hospital but who did not receive PORT were identified. The patterns of first LRF were assessed and evaluated as to whether these areas would be encompassed by our proposed PORT CTV. Results: With a median follow-up of 24 months, 173 of 250 patients (69.2%) experienced disease recurrence. Of the 54 patients with LRF as the first event, 48 (89%) had recurrence within the proposed PORT CTV, and 6 (11%) had failures occurring both within and outside the proposed CTV (all of which occurred in patients with right-lung cancer). Ninety-three percent of failure sites (104 of 112) would have been contained within the proposed PORT CTV. For left-sided lung cancer, the most common lymph node station failure site was 4R, followed by 7, 4L, 6, 10L, and 5. For right-sided lung cancer, the most common site was station 2R, followed by 10R, 4R, and 7. Conclusions: LRF following complete surgery was an important and potentially preventable pattern of failure in stage IIIA(N2) patients. Ipsilateral superior mediastinal recurrences dominated for right-sided tumors, whereas left-sided tumors frequently involved the bilateral superior mediastinum. Most of the LRF sites would have been covered by the proposed PORT CTV. A prospective investigation of patterns of failure after PORT (following our proposed CTV delineation guideline) is presently underway and will be reported in a separate analysis.

  2. Renormalized Volume

    NASA Astrophysics Data System (ADS)

    Gover, A. Rod; Waldron, Andrew

    2017-09-01

    We develop a universal distributional calculus for regulated volumes of metrics that are suitably singular along hypersurfaces. When the hypersurface is a conformal infinity we give simple integrated distribution expressions for the divergences and anomaly of the regulated volume functional valid for any choice of regulator. For closed hypersurfaces or conformally compact geometries, methods from a previously developed boundary calculus for conformally compact manifolds can be applied to give explicit holographic formulæ for the divergences and anomaly expressed as hypersurface integrals over local quantities (the method also extends to non-closed hypersurfaces). The resulting anomaly does not depend on any particular choice of regulator, while the regulator dependence of the divergences is precisely captured by these formulæ. Conformal hypersurface invariants can be studied by demanding that the singular metric obey, smoothly and formally to a suitable order, a Yamabe type problem with boundary data along the conformal infinity. We prove that the volume anomaly for these singular Yamabe solutions is a conformally invariant integral of a local Q-curvature that generalizes the Branson Q-curvature by including data of the embedding. In each dimension this canonically defines a higher dimensional generalization of the Willmore energy/rigid string action. Recently, Graham proved that the first variation of the volume anomaly recovers the density obstructing smooth solutions to this singular Yamabe problem; we give a new proof of this result employing our boundary calculus. Physical applications of our results include studies of quantum corrections to entanglement entropies.

  3. Sequential (gemcitabine/vinorelbine) and concurrent (gemcitabine) radiochemotherapy with FDG-PET-based target volume definition in locally advanced non-small cell lung cancer: first results of a phase I/II study

    PubMed Central

    Gagel, Bernd; Piroth, Marc; Pinkawa, Michael; Reinartz, Patrick; Krohn, Thomas; Kaiser, Hans J; Stanzel, Sven; Breuer, Christian; Asadpour, Branka; Schmachtenberg, Axel; Eble, Michael J

    2007-01-01

    Background The aim of the study was to determine the maximal tolerated dose (MTD) of gemcitabine every two weeks concurrent to radiotherapy, administered during an aggressive program of sequential and simultaneous radiochemotherapy for locally advanced, unresectable non-small cell lung cancer (NSCLC) and to evaluate the efficacy of this regime in a phase II study. Methods 33 patients with histologically confirmed NSCLC were enrolled in a combined radiochemotherapy protocol. 29 patients were assessable for evaluation of toxicity and tumor response. Treatment included two cycles of induction chemotherapy with gemcitabine (1200 mg/m2) and vinorelbine (30 mg/m2) at day 1, 8 and 22, 29 followed by concurrent radiotherapy (2.0 Gy/d; total dose 66.0 Gy) and chemotherapy with gemcitabine every two weeks at day 43, 57 and 71. Radiotherapy planning included [18F] fluorodeoxyglucose positron emission tomography (FDG PET) based target volume definition. 10 patients were included in the phase I study with an initial gemcitabine dose of 300 mg/m2. The dose of gemcitabine was increased in steps of 100 mg/m2 until the MTD was realized. Results MTD was defined for the patient group receiving gemcitabine 500 mg/m2 due to grade 2 (next to grade 3) esophagitis in all patients resulting in a mean body weight loss of 5 kg (SD = 1.4 kg), representing 8% of the initial weight. These patients showed persisting dysphagia 3 to 4 weeks after completing radiotherapy. In accordance with expected complications as esophagitis, dysphagia and odynophagia, we defined the MTD at this dose level, although no dose limiting toxicity (DLT) grade 3 was reached. In the phase I/II median follow-up was 15.7 months (4.1 to 42.6 months). The overall response rate after completion of therapy was 64%. The median overall survival was 19.9 (95% CI: [10.1; 29.7]) months for all eligible patients. The median disease-free survival for all patients was 8.7 (95% CI: [2.7; 14.6]) months. Conclusion After induction

  4. Defining the “Hostile Pelvis” for Intensity Modulated Radiation Therapy: The Impact of Anatomic Variations in Pelvic Dimensions on Dose Delivered to Target Volumes and Organs at Risk in Patients With High-Risk Prostate Cancer Treated With Whole Pelvic Radiation Therapy

    SciTech Connect

    Yirmibeşoğlu Erkal, Eda; Karabey, Sinan; Karabey, Ayşegül; Hayran, Mutlu; Erkal, Haldun Şükrü

    2015-07-15

    Purpose: The aim of this study was to evaluate the impact of variations in pelvic dimensions on the dose delivered to the target volumes and the organs at risk (OARs) in patients with high-risk prostate cancer (PCa) to be treated with whole pelvic radiation therapy (WPRT) in an attempt to define the hostile pelvis in terms of intensity modulated radiation therapy (IMRT). Methods and Materials: In 45 men with high-risk PCa to be treated with WPRT, the target volumes and the OARs were delineated, the dose constraints for the OARs were defined, and treatment plans were generated according to the Radiation Therapy Oncology Group 0924 protocol. Six dimensions to reflect the depth, width, and height of the bony pelvis were measured, and 2 indexes were calculated from the planning computed tomographic scans. The minimum dose (D{sub min}), maximum dose (D{sub max}), and mean dose (D{sub mean}) for the target volumes and OARs and the partial volumes of each of these structures receiving a specified dose (V{sub D}) were calculated from the dose-volume histograms (DVHs). The data from the DVHs were correlated with the pelvic dimensions and indexes. Results: According to an overall hostility score (OHS) calculation, 25 patients were grouped as having a hospitable pelvis and 20 as having a hostile pelvis. Regarding the OHS grouping, the DVHs for the bladder, bowel bag, left femoral head, and right femoral head differed in favor of the hospitable pelvis group, and the DVHs for the rectum differed for a range of lower doses in favor of the hospitable pelvis group. Conclusions: Pelvimetry might be used as a guide to define the challenging anatomy or the hostile pelvis in terms of treatment planning for IMRT in patients with high-risk PCa to be treated with WPRT.

  5. Thinkers on Education. Volume 3.

    ERIC Educational Resources Information Center

    Morsy, Zaghloul, Ed.

    This collection of essays targets universities, social science research institutes, teacher training colleges, and those who lecture and carry out research on the history of ideas and of education. It is the third volume in a series that presents, in English, French, and Spanish, a comprehensive view of great educators of every age and culture.…

  6. Thinkers on Education. Volume 4.

    ERIC Educational Resources Information Center

    Morsy, Zaghloul, Ed.

    This collection of essays targets universities, social science research institutes, teacher training colleges, and those who lecture and carry out research on the history of ideas and of education. It is the fourth volume in a series that presents, in English, French, and Spanish, a comprehensive view of great educators of every age and culture.…

  7. Thinkers on Education. Volume 4.

    ERIC Educational Resources Information Center

    Morsy, Zaghloul, Ed.

    This collection of essays targets universities, social science research institutes, teacher training colleges, and those who lecture and carry out research on the history of ideas and of education. It is the fourth volume in a series that presents, in English, French, and Spanish, a comprehensive view of great educators of every age and culture.…

  8. Pragmatics & Language Learning. Volume 12

    ERIC Educational Resources Information Center

    Kasper, Gabriele, Ed.; Nguyen, Hanh thi, Ed.; Yoshimi, Dina Rudolph, Ed.; Yoshioka, Jim K., Ed.

    2010-01-01

    This volume examines the organization of second language and multilingual speakers' talk and pragmatic knowledge across a range of naturalistic and experimental activities. Based on data collected on Danish, English, Hawai'i Creole, Indonesian, and Japanese as target languages, the contributions explore the nexus of pragmatic knowledge,…

  9. Thinkers on Education. Volume 1.

    ERIC Educational Resources Information Center

    Morsy, Zaghloul, Ed.

    This collection of essays targets universities, social science research institutes, teacher training colleges, and those who lecture and carry out research on the history of ideas and of education. It is the first volume in a series that presents, in English, French, and Spanish, a comprehensive view of great educators of every age and culture.…

  10. Thinkers on Education. Volume 2.

    ERIC Educational Resources Information Center

    Morsy, Zaghloul, Ed.

    This collection of essays targets universities, social science research institutes, teacher training colleges, and those who lecture and carry out research on the history of ideas and of education. It is the second volume in a series that presents, in English, French, and Spanish, a comprehensive view of great educators of every age and culture.…

  11. Pragmatics & Language Learning. Volume 12

    ERIC Educational Resources Information Center

    Kasper, Gabriele, Ed.; Nguyen, Hanh thi, Ed.; Yoshimi, Dina Rudolph, Ed.; Yoshioka, Jim K., Ed.

    2010-01-01

    This volume examines the organization of second language and multilingual speakers' talk and pragmatic knowledge across a range of naturalistic and experimental activities. Based on data collected on Danish, English, Hawai'i Creole, Indonesian, and Japanese as target languages, the contributions explore the nexus of pragmatic knowledge,…

  12. Thinkers on Education. Volume 2.

    ERIC Educational Resources Information Center

    Morsy, Zaghloul, Ed.

    This collection of essays targets universities, social science research institutes, teacher training colleges, and those who lecture and carry out research on the history of ideas and of education. It is the second volume in a series that presents, in English, French, and Spanish, a comprehensive view of great educators of every age and culture.…

  13. Thinkers on Education. Volume 1.

    ERIC Educational Resources Information Center

    Morsy, Zaghloul, Ed.

    This collection of essays targets universities, social science research institutes, teacher training colleges, and those who lecture and carry out research on the history of ideas and of education. It is the first volume in a series that presents, in English, French, and Spanish, a comprehensive view of great educators of every age and culture.…

  14. Thinkers on Education. Volume 3.

    ERIC Educational Resources Information Center

    Morsy, Zaghloul, Ed.

    This collection of essays targets universities, social science research institutes, teacher training colleges, and those who lecture and carry out research on the history of ideas and of education. It is the third volume in a series that presents, in English, French, and Spanish, a comprehensive view of great educators of every age and culture.…

  15. Prostate biopsy volume predicts final tumor volume.

    PubMed

    Zavaski, Michael E; Korus, Adam; Staff, Ilene; Champagne, Alison; Fish-Furhman, Jamie; Tortora, Joseph; Meraney, Anoop; Kesler, Stuart; Wagner, Joseph

    2014-03-01

    To assess the ability of prostate biopsy volume to effectively predict actual tumor volume, and whether increasing the number of prostate biopsy cores improves the ability to forecast actual tumor volume. 765 patients who underwent robotic radical prostatectomy (2009-2010) were identified. Of these, 663 had complete demographics, biopsy, and final pathology data available. The number ofbiopsy samples, biopsy tumor volume, and actual tumor volume were calculated from pathology reports. Data from 663 radical prostatectomy specimens indicated a positive linearrelationship between biopsy tumor volume and actual tumor volume (R=0.524, P< 0.0001). The number ofbiopsy samples collected (i.e., < or =6, 7-8, 9-10, 11-12, 13-14, or > or =15) did not affect the ability of biopsy tumor volume to predict final tumor volume. The routine collection of biopsy tumor volume may prove useful in predicting actual tumor volume and the construction of more effective preoperative nomograms.

  16. Multi-scenario based robust intensity-modulated proton therapy (IMPT) plans can account for set-up errors more effectively in terms of normal tissue sparing than planning target volume (PTV) based intensity-modulated photon plans in the head and neck region.

    PubMed

    Stuschke, Martin; Kaiser, Andreas; Abu Jawad, Jehad; Pöttgen, Christoph; Levegrün, Sabine; Farr, Jonathan

    2013-06-18

    In a previous report, we compared the conformity of robust intensity-modulated proton therapy (IMPT) plans with that of helical tomotherapy plans for re-irradiations of head and neck carcinomas using a fixed set-up error of 2 mm. Here, we varied the maximum set-up errors between 0 and 5 mm and compared the robust IMPT-plans with planning target volume (PTV) based intensity-modulated photon therapy (IMRT). Seven patients were treated with a PTV-based tomotherapy plan. Set-up margins of 0, 2, and 5 mm were subtracted from the PTV to generate target volumes (TV) TV(0mm), TV(2mm), and TV(5mm), for which robust IMPT-plans were created assuming range uncertainties of ±3.5% and using worst case optimization assuming set-up errors of 0, 2, and 5 mm, respectively. Robust optimization makes use of the feature that set-up errors in beam direction alone do not affect the distal and proximal margin for that beam. With increasing set-up errors, the body volumes that were exposed to a selected minimum dose level between 20% and 95% of the prescribed dose decreased. In IMPT-plans with 0 mm set-up error, the exposed body volumes were on average 6.2% ± 0.9% larger than for IMPT-plans with 2 mm set-up error, independent of the considered dose level (p < 0.0001, F-test). In IMPT-plans accounting for 5 mm set-up error, the exposed body volumes were by 11.9% ± 0.8% smaller than for IMPT-plans with 2 mm set-up error at a fixed minimum dose (p < 0.0001, F-test). This set-up error dependence of the normal tissue exposure around the TV in robust IMPT-plans corresponding to the same IMRT-plan led to a decrease in the mean dose to the temporal lobes and the cerebellum, and in the D2% of the brain stem or spinal cord with increasing set-up errors considered during robust IMPT-planning. For recurrent head and neck cancer, robust IMPT-plan optimization led to a decrease in normal tissue exposure with increasing set-up error for target volumes corresponding to the same PTV.

  17. Ways to Environmental Education, Volume 1.

    ERIC Educational Resources Information Center

    Dawson, Joel, Ed.; And Others

    This resource guide is the first of three volumes of environmental education ideas and activities compiled by participants at the Tallahassee Junior Museum for the benefit of other environmental educators. This volume contains ten booklets produced by various community groups to educate their membership or target groups about the environment. The…

  18. Sputter target

    DOEpatents

    Gates, Willard G.; Hale, Gerald J.

    1980-01-01

    The disclosure relates to an improved sputter target for use in the deposition of hard coatings. An exemplary target is given wherein titanium diboride is brazed to a tantalum backing plate using a gold-palladium-nickel braze alloy.

  19. System and method for radiation dose calculation within sub-volumes of a monte carlo based particle transport grid

    DOEpatents

    Bergstrom, Paul M.; Daly, Thomas P.; Moses, Edward I.; Patterson, Jr., Ralph W.; Schach von Wittenau, Alexis E.; Garrett, Dewey N.; House, Ronald K.; Hartmann-Siantar, Christine L.; Cox, Lawrence J.; Fujino, Donald H.

    2000-01-01

    A system and method is disclosed for radiation dose calculation within sub-volumes of a particle transport grid. In a first step of the method voxel volumes enclosing a first portion of the target mass are received. A second step in the method defines dosel volumes which enclose a second portion of the target mass and overlap the first portion. A third step in the method calculates common volumes between the dosel volumes and the voxel volumes. A fourth step in the method identifies locations in the target mass of energy deposits. And, a fifth step in the method calculates radiation doses received by the target mass within the dosel volumes. A common volume calculation module inputs voxel volumes enclosing a first portion of the target mass, inputs voxel mass densities corresponding to a density of the target mass within each of the voxel volumes, defines dosel volumes which enclose a second portion of the target mass and overlap the first portion, and calculates common volumes between the dosel volumes and the voxel volumes. A dosel mass module, multiplies the common volumes by corresponding voxel mass densities to obtain incremental dosel masses, and adds the incremental dosel masses corresponding to the dosel volumes to obtain dosel masses. A radiation transport module identifies locations in the target mass of energy deposits. And, a dose calculation module, coupled to the common volume calculation module and the radiation transport module, for calculating radiation doses received by the target mass within the dosel volumes.

  20. Beyond mean pharyngeal constrictor dose for beam path toxicity in non-target swallowing muscles: dose-volume correlates of chronic radiation-associated dysphagia (RAD) after oropharyngeal intensity modulated radiotherapy

    PubMed Central

    2016-01-01

    Purpose/Objective(s) We sought to identify swallowing muscle dose-response thresholds associated with chronic radiation-associated dysphagia (RAD) after IMRT for oropharyngeal cancer. Materials/Methods T1-4 N0-3 M0 oropharyngeal cancer patients who received definitive IMRT and systemic therapy were examined. Chronic RAD was coded as any of the following ≥ 12 months post-IMRT: videofluoroscopy/endoscopy detected aspiration or stricture, gastrostomy tube and/or aspiration pneumonia. DICOM-RT plan data were autosegmented using a custom region-of-interest (ROI) library and included inferior, middle and superior constrictors (IPC, MPC, and SPC), medial and lateral pterygoids (MPM, LPM), anterior and posterior digastrics (ADM, PDM), intrinsic tongue muscles (ITM), mylo/geniohyoid complex (MHM), genioglossus (GGM), ), masseter (MM), Buccinator (BM), palatoglossus (PGM), and cricopharyngeus (CPM), with ROI dose-volume histograms (DVHs) calculated. Recursive partitioning analysis (RPA) was used to identify dose-volume effects associated with chronic-RAD, for use in a multivariate (MV) model. Results Of 300 patients, 34 (11%) had chronic-RAD. RPA showed DVH-derived MHM V69 (i.e. the volume receiving ≥69Gy), GGM V35, ADM V60, MPC V49, and SPC V70 were associated with chronic-RAD. A model including age in addition to MHM V69 as continuous variables was optimal among tested MV models (AUC 0.835). Conclusion In addition to SPCs, dose to MHM should be monitored and constrained, especially in older patients (>62-years), when feasible. PMID:26897515

  1. LIQUID TARGET

    DOEpatents

    Martin, M.D.; Salsig, W.W. Jr.

    1959-01-13

    A liquid handling apparatus is presented for a liquid material which is to be irradiated. The apparatus consists essentially of a reservoir for the liquid, a target element, a drain tank and a drain lock chamber. The target is in the form of a looped tube, the upper end of which is adapted to be disposed in a beam of atomic particles. The lower end of the target tube is in communication with the liquid in the reservoir and a means is provided to continuously circulate the liquid material to be irradiated through the target tube. Means to heat the reservoir tank is provided in the event that a metal is to be used as the target material. The apparatus is provided with suitable valves and shielding to provide maximum safety in operation.

  2. A comparison of internal target volume definition by limited four-dimensional computed tomography, the addition of patient-specific margins, or the addition of generic margins when planning radical radiotherapy for lymph node-positive non-small cell lung cancer.

    PubMed

    Hughes, S; McClelland, J; Chandler, A; Adams, M; Boutland, J; Withers, D; Ahmad, S; Blackall, J; Tarte, S; Hawkes, D; Landau, D

    2008-05-01

    Radical radiotherapy for stage II/III non-small cell lung cancer (NSCLC) includes the primary tumour and positive mediastinal lymph nodes in the clinical target volume (CTV). These move independently of each other in magnitude and direction during respiration. To prevent a geographical miss, a generic margin is usually added to the CTV to create an internal target volume (ITV). Previous studies have investigated the use of additional breath-hold computed tomography to generate patient-specific ITVs for primary tumours alone. We used a similar technique to investigate the generation of patient-specific and generic ITVs for CTVs that include mediastinal lymph nodes. Thirteen patients with node-positive NSCLC had two limited end-tidal breath-hold computed tomography scans in addition to their planning computed tomography. The CTV was segmented in each scan and a rigid registration was carried out on the vertebral columns to align them. Different methods for generating an ITV were then analysed. Generic margins provided >95% mean coverage of the reference ITV. However, with the exception of 1cm expansion margins, there were cases of inadequate coverage (<95%) for each ITV. With increasing ITV margins there was a small increase in reference ITV coverage, but at the expense of a large increase in the volume of normal tissue within the ITV. For stage II/III NSCLC, ITV generation by the addition of a generic margin is not optimal. It can result in both geographical miss and excessive irradiation of normal tissue in the same treatment plan. A simple method for producing a patient-specific ITV is to co-register end-tidal breath-hold computed tomography scans to the planning scan. Further work is required to determine whether end-tidal breath-hold scans are representative of the anatomy at the limits of tidal respiration. Planning strategies are also needed to account for breathing cycle variation during a course of radiotherapy.

  3. Estimation of daily interfractional larynx residual setup error after isocentric alignment for head and neck radiotherapy: Quality-assurance implications for target volume and organ-at-risk margination using daily CT-on-rails imaging

    PubMed Central

    Baron, Charles A.; Awan, Musaddiq J.; Mohamed, Abdallah S. R.; Akel, Imad; Rosenthal, David I.; Gunn, G. Brandon; Garden, Adam S.; Dyer, Brandon A.; Court, Laurence; Sevak, Parag R; Kocak-Uzel, Esengul; Fuller, Clifton D.

    2016-01-01

    Larynx may alternatively serve as a target or organ-at-risk (OAR) in head and neck cancer (HNC) image-guided radiotherapy (IGRT). The objective of this study was to estimate IGRT parameters required for larynx positional error independent of isocentric alignment and suggest population–based compensatory margins. Ten HNC patients receiving radiotherapy (RT) with daily CT-on-rails imaging were assessed. Seven landmark points were placed on each daily scan. Taking the most superior anterior point of the C5 vertebra as a reference isocenter for each scan, residual displacement vectors to the other 6 points were calculated post-isocentric alignment. Subsequently, using the first scan as a reference, the magnitude of vector differences for all 6 points for all scans over the course of treatment were calculated. Residual systematic and random error, and the necessary compensatory CTV-to-PTV and OAR-to-PRV margins were calculated, using both observational cohort data and a bootstrap-resampled population estimator. The grand mean displacements for all anatomical points was 5.07mm, with mean systematic error of 1.1mm and mean random setup error of 2.63mm, while bootstrapped POIs grand mean displacement was 5.09mm, with mean systematic error of 1.23mm and mean random setup error of 2.61mm. Required margin for CTV-PTV expansion was 4.6mm for all cohort points, while the bootstrap estimator of the equivalent margin was 4.9mm. The calculated OAR-to-PRV expansion for the observed residual set-up error was 2.7mm, and bootstrap estimated expansion of 2.9mm. We conclude that the interfractional larynx setup error is a significant source of RT set-up/delivery error in HNC both when the larynx is considered as a CTV or OAR. We estimate the need for a uniform expansion of 5mm to compensate for set up error if the larynx is a target or 3mm if the larynx is an OAR when using a non-laryngeal bony isocenter. PMID:25679151

  4. On Target.

    ERIC Educational Resources Information Center

    Barbalich, Andrea

    1991-01-01

    Campus public relations professionals offer advice for improving the effectiveness of public relations efforts by (1) setting behavioral goals; (2) targeting audiences carefully; (3) focusing appeals by making messages explicit; (4) connecting the public relations message with larger societal issues; and (5) reaching internal as well as external…

  5. Students Target

    NASA Image and Video Library

    2005-12-19

    Using the JMars targeting software, eighth grade students from Charleston Middle School in Charleston, IL, selected the location of -8.37N and 276.66E for capture by the THEMIS visible camera during Mars Odyssey sixth orbit of Mars on Nov. 22, 2005

  6. Tackling Targets.

    ERIC Educational Resources Information Center

    Further Education Unit, London (England).

    This document is designed to help British training and enterprise councils (TECs) and further education (FE) colleges develop and implement strategies for achieving the National Targets for Education and Training (NTET), which were developed by the Confederation of British Industry in 1992 and endorsed by the British government. The findings from…

  7. Targeting hardwoods

    Treesearch

    Douglass F. Jacobs

    2011-01-01

    Increasing demand for hardwood seedlings has prompted research to identify target seedling characteristics that promote hardwood plantation establishment. Operational establishment of hardwood plantations has typically emphasized seed collection from non-improved genetic sources, bareroot nursery seedling production, and spring planting using machine planters. The...

  8. Target: Lifestyle.

    ERIC Educational Resources Information Center

    Poehlman, Eric T.

    1985-01-01

    "Target: Lifestyle" is a physical education curriculum adopted by Detroit Country Day School which incorporates instruction in nutrition, physical fitness, first aid, and lifetime sports. This curriculum aims to influence student attitudes and lifestyles in health and physical fitness. Four levels of instruction are described. (DF)

  9. Multivariate volume rendering

    SciTech Connect

    Crawfis, R.A.

    1996-03-01

    This paper presents a new technique for representing multivalued data sets defined on an integer lattice. It extends the state-of-the-art in volume rendering to include nonhomogeneous volume representations. That is, volume rendering of materials with very fine detail (e.g. translucent granite) within a voxel. Multivariate volume rendering is achieved by introducing controlled amounts of noise within the volume representation. Varying the local amount of noise within the volume is used to represent a separate scalar variable. The technique can also be used in image synthesis to create more realistic clouds and fog.

  10. Target assembly

    DOEpatents

    Lewis, Richard A.

    1980-01-01

    A target for a proton beam which is capable of generating neutrons for absorption in a breeding blanket includes a plurality of solid pins formed of a neutron emissive target material disposed parallel to the path of the beam and which are arranged axially in a plurality of layers so that pins in each layer are offset with respect to pins in all other layers, enough layers being used so that each proton in the beam will strike at least one pin with means being provided to cool the pins. For a 300 mA, 1 GeV beam (300 MW), stainless steel pins, 12 inches long and 0.23 inches in diameter are arranged in triangular array in six layers with one sixth of the pins in each layer, the number of pins being such that the entire cross sectional area of the beam is covered by the pins with minimum overlap of pins.

  11. Anterior Insula Volume and Guilt

    PubMed Central

    Belden, Andy C.; Barch, Deanna M.; Oakberg, Timothy J.; April, Laura M.; Harms, Michael P.; Botteron, Kelly N.; Luby, Joan L.

    2016-01-01

    IMPORTANCE This is the first study to date to examine volumetric alterations in the anterior insula (AI) as a potential biomarker for the course of childhood major depressive disorder (MDD). OBJECTIVES To examine whether children with a history of preschool-onset (PO) MDD show reduced AI volume, whether a specific symptom of PO MDD (pathological guilt) is related to AI volume reduction (given the known relationship between AI and guilt processing), and whether AI volumes predict subsequent likelihood of having an episode of MDD. DESIGN, SETTING, AND PARTICIPANTS In a prospective longitudinal study, 306 children (age range, 3.00–5.11 years) and caregivers completed DSM diagnostic assessments at 6 annual time points during 10 years as part of the Preschool Depression Study. Magnetic resonance imaging was completed on a subset of 145 school-age children (age range, 6.11–12.11 years). MAIN OUTCOMES AND MEASURES Whole-brain–adjusted AI volume measured using magnetic resonance imaging at school age and children’s diagnosis of MDD any time after their imaging. RESULTS Compared with children without a history of PO MDD, school-age children previously diagnosed as having PO MDD had smaller left and right AI volumes (Wilks Λ = 0.94, F2,124 = 3.37, P = .04, Cohen d = 0.23). However, the effect of PO MDD on reduced AI volumes was better explained by children’s experience of pathological guilt during preschool (Λ = 0.91, F2,120 = 6.17, P = .003, d = .30). When covarying for children’s lifetime history of MDD episodes, their experience of pathological guilt during preschool, as well as their sex and age at the time of imaging, schoolchildren’s right-side AI volume was a significant predictor of being diagnosed as having an MDD episode after imaging (odds ratio, 0.96; 95% CI, 0.01–0.75; P = .03). CONCLUSIONS AND RELEVANCE These results provide evidence that structural abnormalities in AI volume are related to the neurobiology of depressive disorders starting in

  12. Follicular penetration and targeting.

    PubMed

    Lademann, Jürgen; Otberg, Nina; Jacobi, Ute; Hoffman, Robert M; Blume-Peytavi, Ulrike

    2005-12-01

    In the past, intercellular penetration was assumed to be the most important penetration pathway of topically applied substances. First hints that follicular penetration needs to be taken into consideration were confirmed by recent investigations, presented during the workshop "Follicular Penetration and Targeting" at the 4th Intercontinental Meeting of Hair Research Societies", in Berlin 2004. Hair follicles represent an efficient reservoir for the penetration of topically applied substances with subsequent targeting of distinct cell populations, e.g., nestin-expressing follicular bulge cells. The volume of this reservoir can be determined by differential stripping technology. The follicular penetration processes are significantly influenced by the state of the follicular infundibulum; recent experimental investigations could demonstrate that it is essential to distinguish between open and closed hair follicles. Topically applied substances can only penetrate into open hair follicle. Knowledge of follicular penetration is of high clinical relevance for functional targeting of distinct follicular regions. Human hair follicles show a hair-cycle-dependent variation of the dense neuronal and vascular network. Moreover, during hair follicle cycling with initiation of anagen, newly formed vessels occur. Thus, the potential of nestin-expressing hair follicle stem cells to form neurons and blood vessels was investigated.

  13. Accelerator target

    SciTech Connect

    Schlyer, David J.; Ferrieri, Richard A.; Koehler, Conrad

    1999-01-01

    A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression.

  14. Accelerator target

    DOEpatents

    Schlyer, D.J.; Ferrieri, R.A.; Koehler, C.

    1999-06-29

    A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression. 5 figs.

  15. Accelerator target

    SciTech Connect

    Schlyer, D.J.; Ferrieri, R.A.; Koehler, C.

    1999-06-29

    A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression. 5 figs.

  16. Direct interval volume visualization.

    PubMed

    Ament, Marco; Weiskopf, Daniel; Carr, Hamish

    2010-01-01

    We extend direct volume rendering with a unified model for generalized isosurfaces, also called interval volumes, allowing a wider spectrum of visual classification. We generalize the concept of scale-invariant opacity—typical for isosurface rendering—to semi-transparent interval volumes. Scale-invariant rendering is independent of physical space dimensions and therefore directly facilitates the analysis of data characteristics. Our model represents sharp isosurfaces as limits of interval volumes and combines them with features of direct volume rendering. Our objective is accurate rendering, guaranteeing that all isosurfaces and interval volumes are visualized in a crack-free way with correct spatial ordering. We achieve simultaneous direct and interval volume rendering by extending preintegration and explicit peak finding with data-driven splitting of ray integration and hybrid computation in physical and data domains. Our algorithm is suitable for efficient parallel processing for interactive applications as demonstrated by our CUDA implementation.

  17. Targeting circuits

    PubMed Central

    Rajasethupathy, Priyamvada; Ferenczi, Emily; Deisseroth, Karl

    2017-01-01

    Current optogenetic methodology enables precise inhibition or excitation of neural circuits, spanning timescales as needed from the acute (milliseconds) to the chronic (many days or more), for experimental modulation of network activity and animal behavior. Such broad temporal versatility, unique to optogenetic control, is particularly powerful when combined with brain activity measurements that span both acute and chronic timescales as well. This enables, for instance, the study of adaptive circuit dynamics across the intact brain, and tuning interventions to match activity patterns naturally observed during behavior in the same individual. Although the impact of this approach has been greater on basic research than on clinical translation, it is natural to ask if specific neural circuit activity patterns discovered to be involved in controlling adaptive or maladaptive behaviors could become targets for treatment of neuropsychiatric diseases. Here we consider the landscape of such ideas related to therapeutic targeting of circuit dynamics, taking note of developments not only in optical but also in ultrasonic, magnetic, and thermal methods. We note the recent emergence of first-in-kind optogenetically-guided clinical outcomes, as well as opportunities related to the integration of interventions and readouts spanning diverse circuit-physiology, molecular, and behavioral modalities. PMID:27104976

  18. Two characteristic volumes in thermal nuclear multifragmentation

    SciTech Connect

    Karnaukhov, V.A.; Avdeyev, S.P.; Rodionov, V.K.; Kirakosyan, V.V.; Simonenko, A.V.; Rukoyatkin, P.A.; Oeschler, H.; Budzanowski, A.; Karcz, W.; Skwirczynska, I.; Kuzmin, E.A.; Chulkov, L.V.; Norbeck, E.; Botvina, A.S.

    2004-10-01

    The paper is devoted to the experimental determination of the space-time characteristics for the target multifragmentation in p(8.1 GeV)+Au collisions. The experimental data on the fragment charge distribution and kinetic energy spectra are analyzed within the framework of the statistical multifragmentation model. It is found that the partition of hot nuclei is specified after expansion of the target spectator to a volume equal to V{sub t}=(2.9{+-}0.2)V{sub o}, with V{sub o} as the volume at normal density. However, the freezeout volume is found to be V{sub f}=(11{+-}3)V{sub o}. At freezeout, all the fragments are well separated and only the Coulomb force should be taken into account. The results are in accordance with a scenario of spinodal disintegration of hot nuclei.

  19. Directory of Child Day Care Centers. Volume 2: North Central.

    ERIC Educational Resources Information Center

    1986

    Part of a four-volume reference series on licensed child day care facilities across the United States, this volume targets nearly 13,000 facilities in the states of Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin. Arranged alphabetically by state and city, entries include…

  20. Precision volume measurement system.

    SciTech Connect

    Fischer, Erin E.; Shugard, Andrew D.

    2004-11-01

    A new precision volume measurement system based on a Kansas City Plant (KCP) design was built to support the volume measurement needs of the Gas Transfer Systems (GTS) department at Sandia National Labs (SNL) in California. An engineering study was undertaken to verify or refute KCP's claims of 0.5% accuracy. The study assesses the accuracy and precision of the system. The system uses the ideal gas law and precise pressure measurements (of low-pressure helium) in a temperature and computer controlled environment to ratio a known volume to an unknown volume.

  1. X-ray volume imaging in bladder radiotherapy verification

    SciTech Connect

    Henry, Ann M. . E-mail: amhenry@doctors.net.uk; Stratford, Julia; McCarthy, Claire; Davies, Julie; Sykes, Jonathan R.; Amer, Ali; Marchant, Tom; Cowan, Richard; Wylie, James; Logue, John; Livsey, Jacqueline; Khoo, Vincent S.; Moore, Chris; Price, Pat

    2006-03-15

    Purpose: To assess the clinical utility of X-ray volume imaging (XVI) for verification of bladder radiotherapy and to quantify geometric error in bladder radiotherapy delivery. Methods and Materials: Twenty subjects undergoing conformal bladder radiotherapy were recruited. X-ray volume images and electronic portal images (EPIs) were acquired for the first 5 fractions and then once weekly. X-ray volume images were co-registered with the planning computed tomography scan and clinical target volume coverage assessed in three dimensions (3D). Interfraction bladder volume change was described by quantifying changes in bladder volume with time. Bony setup errors were compared from both XVI and EPI. Results: The bladder boundary was clearly visible on coronal XVI views in nearly all images, allowing accurate 3D treatment verification. In 93.5% of imaged fractions, the clinical target volume was within the planning target volume. Most subjects displayed consistent bladder volumes, but 25% displayed changes that could be predicted from the first three XVIs. Bony setup errors were similar whether calculated from XVI or EPI. Conclusions: Coronal XVI can be used to verify 3D bladder radiotherapy delivery. Image-guided interventions to reduce geographic miss and normal tissue toxicity are feasible with this technology.

  2. Tactical Target Acquisition Model (TATAC). Volume II. Users Manual,

    DTIC Science & Technology

    1977-12-01

    ICLOUD - CLOUD COVERAGE (1 a CLEAR, 2 a PAISIAL OIYUCAST, 3 - SOLID OVERCAST) 2 1D ISUWIJ - SUN ANGLE ABOVE HORIZON (I - 90, 2 - 300, 3 - 11.5) 3 ID...SR) JTAT=IDFVJT(4) IP’(ITAT.F𔃺.1) S~O TO 300 10 ICLOUD =7DFVT(1) RTE=FDFVTC 1) TEM~PI=.? IVCCLPOUD.EO.P) TFMP1r.6 1FCICLOUD.F0.3) TFMP1=1. ZKwTEMPI

  3. Tactical Target Identification (TTI) Laboratory Simulation. Volume I.

    DTIC Science & Technology

    1980-03-01

    was a much more difficult task. Some form of lineal to raster conversion package had to be constructed to allow display of the aircraft files. The image...DX, DY) LVECT is a lineal to raster conversion routine that "draws" a straight line in the graphic buffer between (CX, CY) and (CX+DX, CY+DY). LVECT...are calculated from these values. 3.2.5 VECTOR.FTN The three vector algebra routines UNITV, DOTP and CROSSP are used without change from their RT-1l

  4. Liquid Hydrogen: Target, Detector

    SciTech Connect

    Mulholland, G.T.; Harigel, G.G.

    2004-06-23

    In 1952 D. Glaser demonstrated that a radioactive source's radiation could boil 135 deg. C superheated-diethyl ether in a 3-mm O glass vessel and recorded bubble track growth on high-speed film in a 2-cm3 chamber. This Bubble Chamber (BC) promised improved particle track time and spatial resolution and cycling rate. Hildebrand and Nagle, U of Chicago, reported Liquid Hydrogen minimum ionizing particle boiling in August 1953. John Wood created the 3.7-cm O Liquid Hydrogen BC at LBL in January 1954. By 1959 the Lawrence Berkley Laboratory (LBL) Alvarez group's '72-inch' BC had tracks in liquid hydrogen. Within 10 years bubble chamber volumes increased by a factor of a million and spread to every laboratory with a substantial high-energy physics program. The BC, particle accelerators and special separated particle beams created a new era of High Energy Physics (HEP) experimentation. The BC became the largest most complex cryogenic installation at the world's HEP laboratories for decades. The invention and worldwide development, deployment and characteristics of these cryogenic dynamic target/detectors and related hydrogen targets are described.

  5. SECOND TARGET STATION MODERATOR PERFORMANCE WITH A ROTATING TARGET

    SciTech Connect

    Remec, Igor; Gallmeier, Franz X; Rennich, Mark J; McManamy, Thomas J; Lu, W.

    2016-01-01

    Oak Ridge National Laboratory manages and operates the Spallation Neutron Source and the High Flux Isotope Reactor, two of the world's most advanced neutron scattering facilities. Both facilities are funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Science, and are available to researchers from all over the world. Delivering cutting edge science requires continuous improvements and development of the facilities and instruments. The SNS was designed from the outset to accommodate an additional target station, or Second Target Station (STS), and an upgraded accelerator feeding proton beams to STS and the existing First Target Station (FTS). Upgrade of the accelerator and the design and construction of STS are being proposed. The presently considered STS configuration is driven with short (<1 s) proton pulses at 10 Hz repetition rate and 467 kW proton beam power, and is optimized for high intensity and high resolution long wavelength neutron applications. STS will allow installation of 22 beamlines and will expand and complement the current national neutron scattering capabilities. In 2015 the STS studies were performed for a compact tungsten target; first a stationary tungsten plate target was analyzed to considerable details and then dropped in favor of a rotating target. For both target options the proton beam footprint as small as acceptable from mechanical and heat removal aspects is required to arrive at a compact-volume neutron production zone in the target, which is essential for tight coupling of target and moderators and for achieving high-intensity peak neutron fluxes. This paper will present recent STS work with the emphasis on neutronics and moderator performance.

  6. Students' Target

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03648 Ascraeus Mons

    After examining numerous THEMIS images and using the JMars targeting software, eighth grade students from Charleston Middle School in Charleston, IL, selected the location of -8.37N and 276.66E for capture by the THEMIS visible camera during Mars Odyssey's sixth orbit of Mars on Nov. 22, 2005. The students are investigating relationships between channels, craters, and basins on Mars. The Charleston Middle School students participated in the Mars Student Imaging Project (MSIP) and submitted a proposal to use the THEMIS visible camera.

    Image information: VIS instrument. Latitude 8.8S, Longitude 279.6E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  7. Students' Target

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03648 Ascraeus Mons

    After examining numerous THEMIS images and using the JMars targeting software, eighth grade students from Charleston Middle School in Charleston, IL, selected the location of -8.37N and 276.66E for capture by the THEMIS visible camera during Mars Odyssey's sixth orbit of Mars on Nov. 22, 2005. The students are investigating relationships between channels, craters, and basins on Mars. The Charleston Middle School students participated in the Mars Student Imaging Project (MSIP) and submitted a proposal to use the THEMIS visible camera.

    Image information: VIS instrument. Latitude 8.8S, Longitude 279.6E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  8. Variable volume combustor

    DOEpatents

    Ostebee, Heath Michael; Ziminsky, Willy Steve; Johnson, Thomas Edward; Keener, Christopher Paul

    2017-01-17

    The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a linear actuator so as to maneuver the micro-mixer fuel nozzles axially along the liner.

  9. Curiosity Speaks Volumes

    NASA Image and Video Library

    2012-08-27

    This chart shows increases in the volume of data coming back from NASA Mars Curiosity over recent sols. New capabilities of the Electra relay-radios on MRO and Curiosity have greatly increased the volume of data the rover is sending back from Mars.

  10. BEGINNING INDONESIAN, VOLUME 3.

    ERIC Educational Resources Information Center

    DYEN, ISIDORE

    VOLUME 3 OF A 4 VOLUME WORK ON BEGINNING INDONESIAN CONTAINS LESSONS 13-18 OF A TOTAL OF 24. THESE SIX LESSONS PROVIDE DRILLS IN BASIC INDONESIAN SENTENCE PATTERNS INVOLVING THE USE OF THE PASSIVE VOICE, PRONUNCIATION TECHNIQUES, ORTHOGRAPHY, FINAL VOWELS, AND FINAL SYLLABLES. LANGUAGE DRILLS ARE ALSO PROVIDED CONCERNING THE MONTHS OF THE YEAR AND…

  11. BEGINNING INDONESIAN. VOLUME 2.

    ERIC Educational Resources Information Center

    DYEN, ISIDORE

    VOLUME 2 OF A 4-VOLUME WORK ON BEGINNING INDONESIAN CONTAINS LESSONS 7-12 OF A TOTAL OF 24. THESE SIX LESSONS PROVIDE DRILLS IN BASIC INDONESIAN SENTENCE PATTERNS INVOLVING THE USE OF DIFFICULT VERBS, THE ACTIVE VOICE, INVERTED NARRATIVE CLAUSES, INTERROGATIVE WORDS, AND COUNTING METHODS. RELATED REPORTS ARE ED 010 456 THROUGH ED 010 459. (GD)

  12. BEGINNING INDONESIAN. VOLUME 1.

    ERIC Educational Resources Information Center

    DYEN, ISIDORE

    VOLUME 1 OF A 4-VOLUME WORK ON BEGINNING INDONESIAN CONTAINS THE FIRST 6 LESSONS OF A TOTAL OF 24. THESE SIX LESSONS PROVIDE DRILLS IN BASIC INDONESIAN SENTENCE PATTERNS INVOLVING THE USE OF TERMS OF ADDRESS, POLITE FORMULAS AND RESPONSES, AUXILIARIES, COMMANDS, AND ABSOLUTE EXPRESSIONS. RELATED REPORTS ARE ED 010 456 THROUGH ED 010 459. (GD)…

  13. Volume Perimetry: measurement in depth of visual field loss

    PubMed Central

    Satgunam, PremNandhini; Apfelbaum, Henry L; Peli, Eli

    2012-01-01

    Purpose Volume scotomas are three-dimensional regions of space that are not visible to the observer. Volume perimetry maps volume scotomas. Volume scotomas predicted from combining monocular visual fields assume known fixation locus (mainly foveal). However fixation loci are not always known, especially with central field loss. Here we demonstrate methods for measuring and calculating volume scotomas and discuss their practical implications. Methods Three patients (bitemporal hemianopia, binasal scotoma, and central field loss (CFL)) were evaluated. Slices through the volume scotomas were measured at three distances: at the plane of fixation, at a plane anterior to fixation (representing anterior volume perimetry), and a plane posterior to fixation (representing posterior volume perimetry). For anterior volume perimetry, patients fixated on a screen 100cm away through a beamsplitter that reflected the perimetric stimulus (at 50cm). For posterior volume perimetry, patients fixated on a near target (50cm) while perimetric stimuli were presented on a screen 150cm beyond the fixation. At the plane of fixation, monocular visual fields under binocular viewing conditions were measured using a computerized dichoptic perimeter. Results Posterior and anterior volume scotomas were documented in patients with bitemporal hemianopia and binasal scotomas respectively. The CFL patient demonstrated both anterior and posterior volume scotomas. Scotoma magnitude was considered to determine its effect on visual function. Conclusions Direct measurement of volume scotomas can be performed. Anterior and posterior volume visual fields can vary substantially from conventional binocular perimetry measured at the fixation plane, revealing blind areas not otherwise identified. These volume scotomas are likely to impair functional vision such as driving (for bitemporal hemianopes) and near work with small hand tools (for binasal scotomas). Patients with CFL will have impaired functional vision

  14. LLE Review Quarterly Report (April-June 1985). Volume 23

    SciTech Connect

    Skupsky, S.

    1985-06-01

    This volume of the LLE Review contains articles on the fully UV converted OMEGA laser system, mass-ablation rate experiments, reactor-size target designs, plasma processes in the target corona, degradation in optical performance of dielectric thin films, and the National Laser Users Facility activities for April-June 1985.

  15. Live ultrasound volume reconstruction using scout scanning

    NASA Astrophysics Data System (ADS)

    Meyer, Amelie; Lasso, Andras; Ungi, Tamas; Fichtinger, Gabor

    2015-03-01

    Ultrasound-guided interventions often necessitate scanning of deep-seated anatomical structures that may be hard to visualize. Visualization can be improved using reconstructed 3D ultrasound volumes. High-resolution 3D reconstruction of a large area during clinical interventions is challenging if the region of interest is unknown. We propose a two-stage scanning method allowing the user to perform quick low-resolution scouting followed by high-resolution live volume reconstruction. Scout scanning is accomplished by stacking 2D tracked ultrasound images into a low-resolution volume. Then, within a region of interest defined in the scout scan, live volume reconstruction can be performed by continuous scanning until sufficient image density is achieved. We implemented the workflow as a module of the open-source 3D Slicer application, within the SlicerIGT extension and building on the PLUS toolkit. Scout scanning is performed in a few seconds using 3 mm spacing to allow region of interest definition. Live reconstruction parameters are set to provide good image quality (0.5 mm spacing, hole filling enabled) and feedback is given during live scanning by regularly updated display of the reconstructed volume. Use of scout scanning may allow the physician to identify anatomical structures. Subsequent live volume reconstruction in a region of interest may assist in procedures such as targeting needle interventions or estimating brain shift during surgery.

  16. Unsteady flow volumes

    SciTech Connect

    Becker, B.G.; Lane, D.A.; Max, N.L.

    1995-03-01

    Flow volumes are extended for use in unsteady (time-dependent) flows. The resulting unsteady flow volumes are the 3 dimensional analog of streamlines. There are few examples where methods other than particle tracing have been used to visualize time varying flows. Since particle paths can become convoluted in time there are additional considerations to be made when extending any visualization technique to unsteady flows. We will present some solutions to the problems which occur in subdivision, rendering, and system design. We will apply the unsteady flow volumes to a variety of field types including moving multi-zoned curvilinear grids.

  17. Method and apparatus for producing cryogenic targets

    DOEpatents

    Murphy, J.T.; Miller, J.R.

    1984-08-07

    An improved method and apparatus are given for producing cryogenic inertially driven fusion targets in the fast isothermal freezing (FIF) method. Improved coupling efficiency and greater availability of volume near the target for diagnostic purposes and for fusion driver beam propagation result. Other embodiments include a new electrical switch and a new explosive detonator, all embodiments making use of a purposeful heating by means of optical fibers. 6 figs.

  18. Method and apparatus for producing cryogenic targets

    DOEpatents

    Murphy, James T.; Miller, John R.

    1984-01-01

    An improved method and apparatus are given for producing cryogenic inertially driven fusion targets in the fast isothermal freezing (FIF) method. Improved coupling efficiency and greater availability of volume near the target for diagnostic purposes and for fusion driver beam propagation result. Other embodiments include a new electrical switch and a new explosive detonator, all embodiments making use of a purposeful heating by means of optical fibers.

  19. Method and apparatus for producing cryogenic targets

    SciTech Connect

    Murphy, J.T.; Miller, J.R.

    1981-08-28

    An improved method and apparatus are given for producing cryogenic inertially driven fusion targets in the fast isothermal freezing (FIF) method. Improved coupling efficiency and greater availability of volume near the target for diagnostic purposes and for fusion driver beam propagation result. Other embodiments include a new electrical switch and a new explosive detonator, all embodiments making use of a purposeful heating by means of optical fibers.

  20. Environmental chemistry: Volume A

    SciTech Connect

    Yen, T.F.

    1999-08-01

    This is an extensive introduction to environmental chemistry for engineering and chemical professionals. The contents of Volume A include a brief review of basic chemistry prior to coverage of litho, atmo, hydro, pedo, and biospheres.

  1. Stereometric body volume measurement

    NASA Technical Reports Server (NTRS)

    Herron, R. E.

    1975-01-01

    The following studies are reported: (1) effects of extended space flight on body form of Skylab astronauts using biostereometrics; (2) comparison of body volume determinations using hydrostatic weighing and biostereometrics; and (3) training of technicians in biostereometric principles and procedures.

  2. Urine 24-hour volume

    MedlinePlus

    ... insipidus - renal Diabetes insipidus - central Diabetes High fluid intake Some forms of kidney disease Use of diuretic medicines Alternative Names Urine volume; 24-hour urine collection; Urine protein - 24 hour Images Urine sample Female urinary tract ...

  3. Factors influencing the difference between forecasted and actual drug sales volumes under the price-volume agreement in South Korea.

    PubMed

    Park, Sun-Young; Han, Euna; Kim, Jini; Lee, Eui-Kyung

    2016-08-01

    This study analyzed factors contributing to increases in the actual sales volumes relative to forecasted volumes of drugs under price-volume agreement (PVA) policy in South Korea. Sales volumes of newly listed drugs on the national formulary are monitored under PVA policy. When actual sales volume exceeds the pre-agreed forecasted volume by 30% or more, the drug is subject to price-reduction. Logistic regression assessed the factors related to whether drugs were the PVA price-reduction drugs. A generalized linear model with gamma distribution and log-link assessed the factors influencing the increase in actual volumes compared to forecasted volume in the PVA price-reduction drugs. Of 186 PVA monitored drugs, 34.9% were price-reduction drugs. Drugs marketed by pharmaceutical companies with previous-occupation in the therapeutic markets were more likely to be PVA price-reduction drugs than drugs marketed by firms with no previous-occupation. Drugs of multinational pharmaceutical companies were more likely to be PVA price-reduction drugs than those of domestic companies. Having more alternative existing drugs was significantly associated with higher odds of being PVA price-reduction drugs. Among the PVA price-reduction drugs, the increasing rate of actual volume compared to forecasted volume was significantly higher in drugs with clinical usefulness. By focusing the negotiation efforts on those target drugs, PVA policy can be administered more efficiently with the improved predictability of the drug sales volumes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Automatic detection of sweep-meshable volumes

    DOEpatents

    Tautges; Timothy J. , White; David R.

    2006-05-23

    A method of and software for automatically determining whether a mesh can be generated by sweeping for a representation of a geometric solid comprising: classifying surface mesh schemes for surfaces of the representation locally using surface vertex types; grouping mappable and submappable surfaces of the representation into chains; computing volume edge types for the representation; recursively traversing surfaces of the representation and grouping the surfaces into source, target, and linking surface lists; and checking traversal direction when traversing onto linking surfaces.

  5. Hypervelocity Impact (HVI). Volume 1; General Introduction

    NASA Technical Reports Server (NTRS)

    Gorman, Michael R.; Ziola, Steven M.

    2007-01-01

    During 2003 and 2004, the Johnson Space Center's White Sands Testing Facility in Las Cruces, New Mexico conducted hypervelocity impact tests on the space shuttle wing leading edge. Hypervelocity impact tests were conducted to determine if Micro-Meteoroid/Orbital Debris impacts could be reliably detected and located using simple passive ultrasonic methods. This volume contains an executive summary, overview of the method, brief descriptions of all targets, and highlights of results and conclusions.

  6. WYSIWYG (What You See is What You Get) volume visualization.

    PubMed

    Guo, Hanqi; Mao, Ningyu; Yuan, Xiaoru

    2011-12-01

    In this paper, we propose a volume visualization system that accepts direct manipulation through a sketch-based What You See Is What You Get (WYSIWYG) approach. Similar to the operations in painting applications for 2D images, in our system, a full set of tools have been developed to enable direct volume rendering manipulation of color, transparency, contrast, brightness, and other optical properties by brushing a few strokes on top of the rendered volume image. To be able to smartly identify the targeted features of the volume, our system matches the sparse sketching input with the clustered features both in image space and volume space. To achieve interactivity, both special algorithms to accelerate the input identification and feature matching have been developed and implemented in our system. Without resorting to tuning transfer function parameters, our proposed system accepts sparse stroke inputs and provides users with intuitive, flexible and effective interaction during volume data exploration and visualization.

  7. Chloride channels as drug targets

    PubMed Central

    Verkman, Alan S.; Galietta, Luis J. V.

    2013-01-01

    Chloride channels represent a relatively under-explored target class for drug discovery as elucidation of their identity and physiological roles has lagged behind that of many other drug targets. Chloride channels are involved in a wide range of biological functions, including epithelial fluid secretion, cell-volume regulation, neuroexcitation, smooth-muscle contraction and acidification of intracellular organelles. Mutations in several chloride channels cause human diseases, including cystic fibrosis, macular degeneration, myotonia, kidney stones, renal salt wasting and hyperekplexia. Chloride-channel modulators have potential applications in the treatment of some of these disorders, as well as in secretory diarrhoeas, polycystic kidney disease, osteoporosis and hypertension. Modulators of GABAA (γ-aminobutyric acid A) receptor chloride channels are in clinical use and several small-molecule chloride-channel modulators are in preclinical development and clinical trials. Here, we discuss the broad opportunities that remain in chloride-channel-based drug discovery. PMID:19153558

  8. Volume MLS ray casting.

    PubMed

    Ledergerber, Christian; Guennebaud, Gaël; Meyer, Miriah; Bächer, Moritz; Pfister, Hanspeter

    2008-01-01

    The method of Moving Least Squares (MLS) is a popular framework for reconstructing continuous functions from scattered data due to its rich mathematical properties and well-understood theoretical foundations. This paper applies MLS to volume rendering, providing a unified mathematical framework for ray casting of scalar data stored over regular as well as irregular grids. We use the MLS reconstruction to render smooth isosurfaces and to compute accurate derivatives for high-quality shading effects. We also present a novel, adaptive preintegration scheme to improve the efficiency of the ray casting algorithm by reducing the overall number of function evaluations, and an efficient implementation of our framework exploiting modern graphics hardware. The resulting system enables high-quality volume integration and shaded isosurface rendering for regular and irregular volume data.

  9. [Planned 3-dimensional low-volume conformal irradiation of a local prostatic carcinoma].

    PubMed

    Wachter, S; Gerstner, N; Dieckmann, K; Stampfer, M; Hawliczek, R; Pötter, R

    1997-05-01

    Recent data have shown a significant reduction of acute side effects by means of a three-dimensional planned conformal radiotherapy of carcinoma of the prostate compared to treatment techniques used before. Theoretically, an optimized field coverage of the planning target volume should result in a reduction of treated bladder and rectum volumes. We studied the effects of individualized blocks on treatment volumes, planning target volumes, irradiated bladder and rectum volumes on basis of three-dimensional treatment planning by means of beam's-eye-view technique. We compared dose-volume-histograms of 2 different planning models, a (fictitious) open 4-field-box-technique and a technique with conformal blocked fields designed from the beam's-eye-view display (prescribed dose 66 Gy, daily single fraction 2 Gy). Plans of 115 patients with localized prostate cancer treated from January 1994 to February 1996 were analyzed. Using individualized fields treatment volume (covered by the 90%-isodose) was reduced by 23% on the average in comparison to the planning model without blocks. The averaged difference of treated volume and planning target volume, as a grade of efficiency of conformation, was reduced by 38% (496 cm3 303 cm3) using individualized blocks. 23% of the treated bladder volume and 13% of the treated rectum volume had been saved on the average. Nevertheless, at least 11.5% of the bladder volume and 27.6% of the contoured rectum volume were treated with the prescribed dose (55 Gy = 100%). The comparison of dose-volume-histogram-data showed that especially high dose volumes of organs at risk had been saved by means of individualized blocks created from the beam's-eye-view. The blocks did not affect the dose distribution of the planning target volume adversely. Consequently the impact of these data on the extent of side effects and local tumor control has to be proven.

  10. Aperiodic Volume Optics

    NASA Astrophysics Data System (ADS)

    Gerke, Tim D.

    Presented in this thesis is an investigation into aperiodic volume optical devices. The three main topics of research and discussion are the aperiodic volume optical devices that we call computer-generated volume holograms (CGVH), defects within periodic 3D photonic crystals, and non-periodic, but ordered 3D quasicrystals. The first of these devices, CGVHs, are designed and investigated numerically and experimentally. We study the performance of multi-layered amplitude computer-generated volume holograms in terms of efficiency and angular/frequency selectivity. Simulation results show that such aperiodic devices can increase diffraction efficiency relative to periodic amplitude volume holograms while maintaining angular and wavelength selectivity. CGVHs are also designed as voxelated volumes using a new projection optimization algorithm. They are investigated using a volumetric diffraction simulation and a standard 3D beam propagation technique as well as experimentally. Both simulation and experiment verify that the structures function according to their design. These represent the first diffractive structures that have the capacity for generating arbitrary transmission and reflection wave fronts and that provide the ability for multiplexing arbitrary functionality given different illumination conditions. Also investigated and discussed in this thesis are 3D photonic crystals and quasicrystals. We demonstrate that these devices can be fabricated using a femtosecond laser direct writing system that is particularly appropriate for fabrication of such arbitrary 3D structures. We also show that these devices can provide 3D partial bandgaps which could become complete bandgaps if fabricated using high index materials or by coating lower index materials with high index metals. Our fabrication method is particularly suited to the fabrication of engineered defects within the periodic or quasi-periodic systems. We demonstrate the potential for fabricating defects within

  11. Targeted Therapy for Cancer

    Cancer.gov

    Targeted therapy is a type of cancer treatment that targets the changes in cancer cells that help them grow, divide, and spread. Learn how targeted therapy works against cancer and about side effects that may occur.

  12. FLES News, Volume 8.

    ERIC Educational Resources Information Center

    FLES News, 1995

    1995-01-01

    Volume 8 of the newslettter for teachers of foreign language in elementary schools (FLES) features these articles: "The Teacher's Voice: Action Research in Your Classroom" (Anna Uhl Chamot); "Teacher Preparation: Using Videotapes in a Teaching Practicum" (Gisela Ernst, Kerri J. Richard); and "Hawaiian Language Immersion:…

  13. Navajo Biographies. Volume I.

    ERIC Educational Resources Information Center

    Hoffman, Virginia

    The life stories of eight Navajo ("Dine", their term for themselves) leaders are presented in volume one of this collection of biographies. Interspersed with portraits, drawings, and maps, the narrative chronologically covers the time period from 1766 when the Navajos lived on land under the rule of Spain into the twentieth century and…

  14. Volume measuring system

    NASA Technical Reports Server (NTRS)

    Oele, J. S.

    1975-01-01

    Chamber is designed to be airtight; it includes face mask for person to breathe outside air so that he does not disturb chamber environment. Chamber includes piston to vary air volume inside. Also included are two microphone transducers which record pressure information inside chamber.

  15. Children's Literature. Volume 3.

    ERIC Educational Resources Information Center

    Butler, Francelia, Ed.; Brockman, Bennett A., Ed.

    This volume applies critical literary standards to the field of children's literature in a long-range effort to improve its quality and teaching. Contributors and editors represent international scholarship in all of the humanities, as well as in the specific area of children's literature. Articles span topics from European children's literature…

  16. Leadership Abstracts, Volume 10.

    ERIC Educational Resources Information Center

    Milliron, Mark D., Ed.

    1997-01-01

    The abstracts in this series provide brief discussions of issues related to leadership, administration, professional development, technology, and education in community colleges. Volume 10 for 1997 contains the following 12 abstracts: (1) "On Community College Renewal" (Nathan L. Hodges and Mark D. Milliron); (2) "The Community College Niche in a…

  17. Liter - Metric Volume.

    ERIC Educational Resources Information Center

    Sisk, Diane

    This autoinstructional program, developed as part of a general science course, is offered for students in the middle schools. Mathematics of fractions and decimals is considered to be prerequisite knowledge. The behavioral objectives are directed toward mastery of determining volumes of solid objects using the water displacement method as well as…

  18. RESEARCH ABSTRACTS, VOLUME VI.

    ERIC Educational Resources Information Center

    COLETTE, SISTER M.

    THIS SIXTH VOLUME OF RESEARCH ABSTRACTS PRESENTS REPORTS OF 35 RESEARCH STUDIES COMPLETED BY CANDIDATES FOR THE MASTER'S DEGREE AT THE CARDINAL STRITCH COLLEGE IN 1964. TWENTY-NINE STUDIES ARE CONCERNED WITH READING, AND SIX ARE CONCERNED WITH THE EDUCATION OF THE MENTALLY HANDICAPPED. OF THE READING STUDIES, FIVE PERTAIN TO THE JUNIOR HIGH LEVEL…

  19. Deafness Annual, Volume II.

    ERIC Educational Resources Information Center

    Norris, Arthur G., Ed.

    Presented is the second of two volumes on deafness which contains 12 papers and a review of programs or grants sponsored by the federal government and other groups. Larry Stewart identifies the deaf in "A Truly Silent Minority". In the "Seven-Faces of Deafness", G. Loyd tells what deafness means to seven people. E. Mindel maintains that parents…

  20. Another year, another volume

    Treesearch

    Bill Block

    2012-01-01

    This issue represents the final one in volume 76 of Journal of Wildlife Management. As this one is pretty much in the books, one cannot help but wonder what the future holds for the journal. Lenny Brennan is putting together a piece for Wildlife Society Bulletin to examine how The Wildlife Society publications have changed through time. He solicited input from past and...

  1. Exhibit Volume I.

    ERIC Educational Resources Information Center

    Mathematica, Princeton, NJ.

    As part of the second phase of a two-phase study of the condition and needs of the live professional theatre in America since the mid-1960's, this volume contains statements of the problems and solutions identified by the following theatre organizations: (1) Actors' Equity Association, (2) Off-Off Broadway Alliance, (3) Alliance for American…

  2. Negotiating Salaries, Volume I.

    ERIC Educational Resources Information Center

    Educational Service Bureau, Inc., Washington, DC.

    This volume deals with concepts important to the effective negotiation of salaries in public schools. The discussion covers the compensation patterns in education, the goals and pressures affecting reacher negotiators, salaries in relation to other benefits and proposals, extra pay for extra duties and merit pay, and the stance of the negotiators…

  3. Strategic Plan. Volume 1

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The purpose of this document is to present the strategic plan and associated organizational structure that the National Space Biomedical Research Institute (NSBRI) will utilize to achieve the defined mission and objectives provided by NASA. Much of the information regarding the background and establishment of the NSBRI by NASA has been provided in other documentation and will not be repeated in this Strategic Plan. This Strategic Plan is presented in two volumes. Volume I (this volume) begins with an Introduction (Section 2) that provides the Institute's NASA-defined mission and objectives, and the organizational structure adopted to implement these through three Strategic Programs: Countermeasure Research; Education, Training and Outreach; and Cooperative Research and Development. These programs are described in Sections 3 to 5. Each program is presented in a similar way, using four subsections: Goals and Objectives; Current Strategies; Gaps and Modifications; and Resource Requirements. Section 6 provides the administrative infrastructure and total budget required to implement the Strategic Programs and assures that they form a single cohesive plan. This plan will ensure continued success of the Institute for the next five years. Volume II of the Strategic Plan provides an in-depth analysis of the current and future strategic programs of the 12 current NSBRI teams, including their goals, objectives, mutual interactions and schedules.

  4. Transorbital target localization in the porcine model

    NASA Astrophysics Data System (ADS)

    DeLisi, Michael P.; Mawn, Louise A.; Galloway, Robert L.

    2013-03-01

    Current pharmacological therapies for the treatment of chronic optic neuropathies such as glaucoma are often inadequate due to their inability to directly affect the optic nerve and prevent neuron death. While drugs that target the neurons have been developed, existing methods of administration are not capable of delivering an effective dose of medication along the entire length of the nerve. We have developed an image-guided system that utilizes a magnetically tracked flexible endoscope to navigate to the back of the eye and administer therapy directly to the optic nerve. We demonstrate the capabilities of this system with a series of targeted surgical interventions in the orbits of live pigs. Target objects consisted of NMR microspherical bulbs with a volume of 18 μL filled with either water or diluted gadolinium-based contrast, and prepared with either the presence or absence of a visible coloring agent. A total of 6 pigs were placed under general anesthesia and two microspheres of differing color and contrast content were blindly implanted in the fat tissue of each orbit. The pigs were scanned with T1-weighted MRI, image volumes were registered, and the microsphere containing gadolinium contrast was designated as the target. The surgeon was required to navigate the flexible endoscope to the target and identify it by color. For the last three pigs, a 2D/3D registration was performed such that the target's coordinates in the image volume was noted and its location on the video stream was displayed with a crosshair to aid in navigation. The surgeon was able to correctly identify the target by color, with an average intervention time of 20 minutes for the first three pigs and 3 minutes for the last three.

  5. Advanced Target Tracker Concepts

    DTIC Science & Technology

    1980-01-01

    Multiple tar-ets, Target tracking, Target cueing, Target screening, Image processing, Scene analysis, Artificial intelligenv ~e 4 ~’ Ati.ýT PACT (CONTINUE...in successive frames. Furthermore, the artificial intelligence capability of the scene model will allow inference of the target shape from its

  6. Fissure Integrity and Volume Reduction in Emphysema: A Retrospective Study.

    PubMed

    de Oliveira, Hugo Goulart; de Oliveira, Silvia Martins; Rambo, Rafael Ramos; de Macedo Neto, Amarilio Vieira

    2016-01-01

    One-way endobronchial valves (EBVs) relieve symptoms of emphysema, particularly in patients without collateral ventilation between the target and adjacent lobes. Pretreatment knowledge of fissure integrity could serve as an aid in indicating EBV interventions. This study aimed to investigate the relationship between software-measured lung fissure integrity and clinically relevant lung volume reduction (≥350 ml) in emphysema patients treated with one-way EBVs using a lobar exclusion strategy. Of 108 patients treated between March 2008 and July 2014, 38 had both baseline and follow-up computed tomography (CT) scans acquired following a specific protocol for quantitative CT analysis and were included in the study (total of 39 treatments, two lungs treated in 1 patient). Outcome measures were fissure integrity measured on baseline CT scans, difference between pre- and postoperative lung volume (considering the lowest measured postoperative volume), and correlation between fissure integrity and volume change. Fissure integrity ≥75% correlated with volume reduction ≥350 ml (Spearman coefficient: -0.65; p < 0.01). The mean and median volume reductions were 1,223.96 ± 907.5 ml and 663 ml, respectively, for lungs with fissure integrity ≥75% (n = 31). The accuracy of fissure integrity ≥75% in predicting a volume reduction was 87.2%. The positive predictive value of fissure integrity ≥75% to predict a volume reduction ≥350 ml was 83.9%, and it was 70% for fissure integrity 75-90% and 90.5% for fissure integrity >90%. A target lobe volume reduction using EBVs is possible with lung fissure integrity ≥75%. For patients with fissure integrity between 75 and 90%, a further evaluation of interlobar ventilation should be performed. A clinically relevant volume reduction following treatment with EBVs is likely with any level of fissure integrity >90%. © 2016 S. Karger AG, Basel.

  7. Adaptive Target Tracking for Underwater Maneuvering Targets.

    DTIC Science & Technology

    1979-12-01

    Gholson and Moose [5] to three-dimensional tracking. The general approach which uses the "adaptive semi-Markov man- euver model" of [4] and [5] implies a...of a maneuvering target (U)," U.S. Naval J. Underwater Acoustics, July 1973. [51 N. H. Gholson and R. L. Moose, "Maneuvering target tracking using

  8. Polarized internal target apparatus

    DOEpatents

    Holt, R.J.

    1984-10-10

    A polarized internal target apparatus with a polarized gas target of improved polarization and density (achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms) is described.

  9. Polarized internal target apparatus

    DOEpatents

    Holt, Roy J.

    1986-01-01

    A polarized internal target apparatus with a polarized gas target of improved polarization and density achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms.

  10. Electrically charged targets

    DOEpatents

    Goodman, Ronald K.; Hunt, Angus L.

    1984-01-01

    Electrically chargeable laser targets and method for forming such charged targets in order to improve their guidance along a predetermined desired trajectory. This is accomplished by the incorporation of a small amount of an additive to the target material which will increase the electrical conductivity thereof, and thereby enhance the charge placed upon the target material for guidance thereof by electrostatic or magnetic steering mechanisms, without adversely affecting the target when illuminated by laser energy.

  11. Wound Volume Measurement.

    D