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Doses delivered to small and large breasts and adjacent organs in left breast cancer patients utilizing 3D and IM radiotherapy. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2023. [DOI: 10.1016/j.jrras.2022.100494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Ebert MA, Gulliford S, Acosta O, de Crevoisier R, McNutt T, Heemsbergen WD, Witte M, Palma G, Rancati T, Fiorino C. Spatial descriptions of radiotherapy dose: normal tissue complication models and statistical associations. Phys Med Biol 2021; 66:12TR01. [PMID: 34049304 DOI: 10.1088/1361-6560/ac0681] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 05/28/2021] [Indexed: 12/20/2022]
Abstract
For decades, dose-volume information for segmented anatomy has provided the essential data for correlating radiotherapy dosimetry with treatment-induced complications. Dose-volume information has formed the basis for modelling those associations via normal tissue complication probability (NTCP) models and for driving treatment planning. Limitations to this approach have been identified. Many studies have emerged demonstrating that the incorporation of information describing the spatial nature of the dose distribution, and potentially its correlation with anatomy, can provide more robust associations with toxicity and seed more general NTCP models. Such approaches are culminating in the application of computationally intensive processes such as machine learning and the application of neural networks. The opportunities these approaches have for individualising treatment, predicting toxicity and expanding the solution space for radiation therapy are substantial and have clearly widespread and disruptive potential. Impediments to reaching that potential include issues associated with data collection, model generalisation and validation. This review examines the role of spatial models of complication and summarises relevant published studies. Sources of data for these studies, appropriate statistical methodology frameworks for processing spatial dose information and extracting relevant features are described. Spatial complication modelling is consolidated as a pathway to guiding future developments towards effective, complication-free radiotherapy treatment.
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Affiliation(s)
- Martin A Ebert
- School of Physics, Mathematics and Computing, University of Western Australia, Crawley, Western Australia, Australia
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
- 5D Clinics, Claremont, Western Australia, Australia
| | - Sarah Gulliford
- Department of Radiotherapy Physics, University College Hospitals London, United Kingdom
- Department of Medical Physics and Bioengineering, University College London, United Kingdom
| | - Oscar Acosta
- Univ Rennes, CLCC Eugène Marquis, INSERM, LTSI-UMR 1099, F-35000 Rennes, France
| | | | - Todd McNutt
- Johns Hopkins University, Baltimore, Maryland, United States of America
| | | | - Marnix Witte
- The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Giuseppe Palma
- Institute of Biostructures and Bioimaging, National Research Council, Napoli, Italy
| | - Tiziana Rancati
- Prostate Cancer Program, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Claudio Fiorino
- Medical Physics, San Raffaele Scientific Institute, Milano, Italy
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Kang DJ, Shin YJ, Jeong S, Jung JY, Lee H, Lee B. Development of clinical application program for radiotherapy induced cancer risk calculation using Monte Carlo engine in volumetric-modulated arc therapy. Radiat Oncol 2021; 16:108. [PMID: 34118968 PMCID: PMC8199704 DOI: 10.1186/s13014-020-01722-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 12/06/2020] [Indexed: 11/10/2022] Open
Abstract
Background The purpose of this study is to develop a clinical application program that automatically calculates the effect for secondary cancer risk (SCR) of individual patient. The program was designed based on accurate dose calculations using patient computed tomography (CT) data and Monte Carlo engine. Automated patient-specific evaluation program was configured to calculate SCR. Methods The application program is designed to re-calculate the beam sequence of treatment plan using the Monte Carlo engine and patient CT data, so it is possible to accurately calculate and evaluate scatter and leakage radiation, difficult to calculate in TPS. The Monte Carlo dose calculation system was performed through stoichiometric calibration using patient CT data. The automatic SCR evaluation program in application program created with a MATLAB was set to analyze the results to calculate SCR. The SCR for organ of patient was calculated based on Biological Effects of Ionizing Radiation (BEIR) VII models. The program is designed to sequentially calculate organ equivalent dose (OED), excess absolute risk (EAR), excess relative risk (ERR), and the lifetime attributable risk (LAR) in consideration of 3D dose distribution analysis. In order to confirm the usefulness of the developed clinical application program, the result values from clinical application program were compared with the manual calculation method used in the previous study. Results The OED values calculated in program were calculated to be at most approximately 13.3% higher than results in TPS. The SCR result calculated by the developed clinical application program showed a maximum difference of 1.24% compared to the result of the conventional manual calculation method. And it was confirmed that EAR, ERR and LAR values can be easily calculated by changing the biological parameters. Conclusions We have developed a patient-specific SCR evaluation program that can be used conveniently in the clinic. The program consists of a Monte Carlo dose calculation system for accurate calculation of scatter and leakage radiation and a patient-specific automatic SCR evaluation program using 3D dose distribution. The clinical application program that improved the disadvantages of the existing process can be used as an index for evaluating a patient treatment plan.
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Affiliation(s)
- Dong-Jin Kang
- Department of Radiation Oncology, Inje University Sanggye Paik Hospital, 1342, Dongil-ro, Nowon-gu, Seoul, Korea
| | - Young-Joo Shin
- Department of Radiation Oncology, Inje University Sanggye Paik Hospital, 1342, Dongil-ro, Nowon-gu, Seoul, Korea.
| | - Seonghoon Jeong
- Proton Therapy Center, National Cancer Center, Goyang, Korea
| | - Jae-Yong Jung
- Department of Radiation Oncology, Inje University Sanggye Paik Hospital, 1342, Dongil-ro, Nowon-gu, Seoul, Korea
| | | | - Boram Lee
- Department of Radiation Oncology, Samsung Medical Center, School of Medicine, Sungkyunkwan University, 81, Irwon-Ro, Gangnam-Gu, Seoul, 06351, Korea.
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Coates JTT, Pirovano G, El Naqa I. Radiomic and radiogenomic modeling for radiotherapy: strategies, pitfalls, and challenges. J Med Imaging (Bellingham) 2021; 8:031902. [PMID: 33768134 PMCID: PMC7985651 DOI: 10.1117/1.jmi.8.3.031902] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 01/12/2021] [Indexed: 12/14/2022] Open
Abstract
The power of predictive modeling for radiotherapy outcomes has historically been limited by an inability to adequately capture patient-specific variabilities; however, next-generation platforms together with imaging technologies and powerful bioinformatic tools have facilitated strategies and provided optimism. Integrating clinical, biological, imaging, and treatment-specific data for more accurate prediction of tumor control probabilities or risk of radiation-induced side effects are high-dimensional problems whose solutions could have widespread benefits to a diverse patient population-we discuss technical approaches toward this objective. Increasing interest in the above is specifically reflected by the emergence of two nascent fields, which are distinct but complementary: radiogenomics, which broadly seeks to integrate biological risk factors together with treatment and diagnostic information to generate individualized patient risk profiles, and radiomics, which further leverages large-scale imaging correlates and extracted features for the same purpose. We review classical analytical and data-driven approaches for outcomes prediction that serve as antecedents to both radiomic and radiogenomic strategies. Discussion then focuses on uses of conventional and deep machine learning in radiomics. We further consider promising strategies for the harmonization of high-dimensional, heterogeneous multiomics datasets (panomics) and techniques for nonparametric validation of best-fit models. Strategies to overcome common pitfalls that are unique to data-intensive radiomics are also discussed.
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Affiliation(s)
- James T. T. Coates
- Massachusetts General Hospital & Harvard Medical School, Center for Cancer Research, Boston, Massachusetts, United States
| | - Giacomo Pirovano
- Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, New York, United States
| | - Issam El Naqa
- Moffitt Cancer Center and Research Institute, Department of Machine Learning, Tampa, Florida, United States
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Singh G, Tyagi A, Thaper D, Kamal R, Kumar V, Oinam AS, Srivastava R, Halder S, Hukku S. Dosimetric analysis of cervical cancer stage IIB patients treated with volumetric modulated arc therapy using plan uncertainty parameters module of Varian Eclipse treatment planning system. Biomed Phys Eng Express 2021; 7. [PMID: 33862601 DOI: 10.1088/2057-1976/abf90a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 04/16/2021] [Indexed: 11/11/2022]
Abstract
Introduction. The present study aims to investigate the dosimetric and radiobiological impact of patient setup errors (PSE) on the target and organs at risk (OAR) of the cervix carcinoma stage IIB patients treated with volumetric-modulated arc therapy (VMAT) delivery technique using plan uncertainty parameters module of Varian Eclipse treatment planning system and in-house developed DVH Analyzer program.Materials and Methods. A total of 976 VMAT plans were generated to simulate the PSE in the base plan that varies from -10 mm to 10 mm in a step size of 1 mm in x- (lateral), y- (craniocaudal), and z- (anteroposterior) directions. The different OAR and tumor (PTV) volumes were delineated in each case. Various plan quality metrics, such as conformity index (CI) and homogeneity index (HI), as well as radiobiological quantities, such as tumor control probability (TCP) and normal tissue control probability (NTCP), were calculated from the DVH bands generated from the cohort of treatment plans associated with each patient case, using an in-house developed 'DVH Analyzer' program. The extracted parameters were statistically analyzed and compared with the base plan's dosimetric parameters having no PSE.Results. The maximum variation of (i) 2.4%, 21.5%, 0.8%, 2.5% in D2ccof bladder, rectum, small bowel and sigmoid colon respectively; (ii) 19.3% and 18.9% in Dmaxof the left and right femoral heads (iii) 16.9% in D95%of PTV (iv) 12.1% in NTCP of sigmoid colon were observed with change of PSE in all directions. TCP was found to be considerably affected for PSEs larger than 4 mm in x+, y+, z+directions and 7 mm in x-, y-and z-directions, respectively.Conclusion. This study presents the effect of PSE on TCP and NTCP for the cervix carcinoma cases treated with VMAT technique and also recommends daily image guidance to mitigate the effects of PSE.
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Affiliation(s)
- Gaganpreet Singh
- Centre for Medical Physics, Panjab University, Chandigarh, India.,Department of Radiotherapy, PGIMER, Chandigarh, India
| | - Atul Tyagi
- Department of Radiation Oncology, Dr B L Kapur Memorial Hospital, Delhi, India
| | - Deepak Thaper
- Centre for Medical Physics, Panjab University, Chandigarh, India.,Department of Radiotherapy, Institute of Liver and Biliary Sciences, New Delhi, India
| | - Rose Kamal
- Centre for Medical Physics, Panjab University, Chandigarh, India.,Department of Radiotherapy, Institute of Liver and Biliary Sciences, New Delhi, India
| | - Vivek Kumar
- Centre for Medical Physics, Panjab University, Chandigarh, India
| | - Arun S Oinam
- Department of Radiotherapy, PGIMER, Chandigarh, India
| | - Ranjana Srivastava
- Department of Radiation Oncology, Dr B L Kapur Memorial Hospital, Delhi, India
| | - Shikha Halder
- Department of Radiation Oncology, Dr B L Kapur Memorial Hospital, Delhi, India
| | - Shelly Hukku
- Department of Radiation Oncology, Dr B L Kapur Memorial Hospital, Delhi, India
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Nicosia L, Sicignano G, Rigo M, Figlia V, Cuccia F, De Simone A, Giaj-Levra N, Mazzola R, Naccarato S, Ricchetti F, Vitale C, Ruggieri R, Alongi F. Daily dosimetric variation between image-guided volumetric modulated arc radiotherapy and MR-guided daily adaptive radiotherapy for prostate cancer stereotactic body radiotherapy. Acta Oncol 2021; 60:215-221. [PMID: 32945701 DOI: 10.1080/0284186x.2020.1821090] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
AIM To evaluate differences between MR-guided daily-adaptive RT (MRgRT) and image-guided RT (IGRT) with or without fiducial markers in prostate cancer (PCa) stereotactic body radiotherapy (SBRT) in terms of dose distribution on critical structures. MATERIAL AND METHODS Two hundred treatment sessions in 40 patients affected by low and intermediate PCa were evaluated. The prescribed dose was 35 Gy in 5 fractions delivered on alternate days. MRgRT patients (10) were daily recontoured, re-planned, and treated with IMRT technique. IGRT patients without (20) and with (10) fiducials were matched on soft tissues or fiducials and treated with VMAT technique. Respective CBCTs were retrospectively delineated and the prescribed plan was overlaid for dosimetric analysis. The daily dose for rectum, bladder, and prostate was registered. RESULTS MRgRT resulted in a significantly lower rate of constraints violation as compared to IGRT without fiducials, especially for rectum V28Gy, rectum V32Gy, rectum V35Gy, rectum Dmax, and bladder Dmax. IGRT with fiducials reported high accuracy levels, comparable to MRgRT. MRgRT and IGRT with fiducials reported no significant prostate CTV underdosage, while IGRT without fiducials was associated with occasional cases of prostate CTV under dosage. CONCLUSION MR-guided daily-adaptive SBRT seems a feasible and accurate strategy for treating prostate cancer with ablative doses. IGRT with the use of fiducials provides a comparable level of accuracy and acceptable real-dose distribution over treatment fractions. Future study will provide additional data regarding the tolerability and the clinical outcome of this new technological approach.
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Affiliation(s)
- Luca Nicosia
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
| | - Gianluisa Sicignano
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
| | - Michele Rigo
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
| | - Vanessa Figlia
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
| | - Francesco Cuccia
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
| | - Antonio De Simone
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
| | - Niccolò Giaj-Levra
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
| | - Rosario Mazzola
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
| | - Stefania Naccarato
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
| | - Francesco Ricchetti
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
| | - Claudio Vitale
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
| | - Ruggero Ruggieri
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
| | - Filippo Alongi
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar, Italy
- University of Brescia
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Morén B, Larsson T, Tedgren ÅC. A mathematical optimization model for spatial adjustments of dose distributions in high dose-rate brachytherapy. ACTA ACUST UNITED AC 2019; 64:225012. [DOI: 10.1088/1361-6560/ab4d8d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Liu H, Xing L. Isodose feature-preserving voxelization (IFPV) for radiation therapy treatment planning. Med Phys 2018; 45:3321-3329. [PMID: 29772065 DOI: 10.1002/mp.12977] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 04/27/2018] [Accepted: 05/07/2018] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Inverse planning involves iterative optimization of a large number of parameters and is known to be a labor-intensive procedure. To reduce the scale of computation and improve characterization of isodose plan, this paper presents an isodose feature-preserving voxelization (IFPV) framework for radiation therapy applications and demonstrates an implementation of inverse planning in the IFPV domain. METHODS A dose distribution in IFPV scheme is characterized by partitioning the voxels into subgroups according to their geometric and dosimetric values. Computationally, the isodose feature-preserving (IFP) clustering combines the conventional voxels that are spatially and dosimetrically close into physically meaningful clusters. A K-means algorithm and support vector machine (SVM) runs sequentially to group the voxels into IFP clusters. The former generates initial clusters according to the geometric and dosimetric information of the voxels and SVM is invoked to improve the connectivity of the IFP clusters. To illustrate the utility of the formalism, an inverse planning framework in the IFPV domain is implemented, and the resultant plans of three prostate IMRT and one head-and-neck cases are compared quantitatively with that obtained using conventional inverse planning technique. RESULTS The IFPV generates models with significant dimensionality reduction without compromising the spatial resolution seen in traditional downsampling schemes. The implementation of inverse planning in IFPV domain is demonstrated. In addition to the improved computational efficiency, it is found that, for the cases studied here, the IFPV-domain inverse planning yields better treatment plans than that of DVH-based planning, primarily because of more effective use of both geometric and dose information of the system during plan optimization. CONCLUSIONS The proposed IFPV provides a low parametric representation of isodose plan without compromising the essential characteristics of the plan, thus providing a practically valuable framework for various applications in radiation therapy.
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Affiliation(s)
- Hongcheng Liu
- Department of Industrial and Systems Engineering, University of Florida, Gainesville, FL, 32611-6595, USA
| | - Lei Xing
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, 94305-5847, USA
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Greco C, Castiglioni S, Fodor A, Mazzetta C, De Cobelli O, Orecchia R. Androgen Ablation Therapy Does not Increase the Risk of Late Morbidity following 3D-conformal Radiotherapy of Organ-confined Prostate Cancer: The Experience of the European Institute of Oncology. TUMORI JOURNAL 2018; 90:567-72. [PMID: 15762358 DOI: 10.1177/030089160409000606] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Aims and Background Androgen ablation therapy in conjunction with radiotherapy-neoadjuvant and adjuvant – has consistently been shown to be associated with improved biochemical and local control, whereas controversy still remains as regards its benefit in terms of overall survival. The objective of this study is to determine the impact of androgen ablation in combination to 3D-conformal radiotherapy on late treatment-related toxicity. Methods 236 patients were treated with 3D-conformal radiotherapy to a total dose ranging from 70 and 78.6 Gy. Fifty-six patients did not receive any form of androgen ablation whereas 176 were given at least 3 months of neoadjuvant androgen ablation. Of these, 64 stayed on androgen ablation for a median time of 6 months post-radiotherapy. Acute toxicity was evaluated weekly during the course of treatment. Late toxicity was assessed at 3-months intervals during the follow-up. Toxicity was scored according to the RTOG criteria. Results The median follow-up was 24.6 months (range, 12-62). The incidence of late genitourinary toxicity was: 3% G2, 3.5% G3, 0.5% G4. The incidence of late gastrointestinal toxicity was: 12% G2, 2% G3, 1% G4. No association was observed between the use of androgen ablation and late treatment-related toxicity. High-risk patients who continued on androgen ablation long-term were not found to have an increased risk of developing late toxicity with respect to those who never had any form of androgen ablation or those only treated neoadjuvantly. Conclusions In our experience, the use of androgen ablation does not impact on late toxicity following high dose 3D-conformal radiotherapy for prostate cancer.
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Affiliation(s)
- Carlo Greco
- Division of Radiation Oncology, European Institute of Oncology, Milan, Italy.
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Adding another dimension to plan evaluation: visualising the dose–volume histogram band in head and neck radiotherapy and exploring its utility. JOURNAL OF RADIOTHERAPY IN PRACTICE 2017. [DOI: 10.1017/s1460396917000206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
AbstractBackgroundTo introduce a method to generate a ‘dose–volume histogram (DVH) band’ for plan evaluation of photon therapy and explore its various potentials.Materials and methodsIntensity-modulated radiotherapy (IMRT) plans for head and neck cancer patients were analysed, retrospectively, for setup errors noted during treatment. From the maximum observed random errors, absolute displacement was calculated using Euclidian formula. The original plan with same beam parameters and leaf sequence were used to generate six plans with shifts applied in three axes in six directions. The DVH curves from these six plans were superimposed to form the DVH band. Plans were reviewed with set tolerance criteria.ResultsMethod to generate and visualise DVH band was developed. DVH bands were created for 20 patients with head and neck cancer who underwent treatment with IMRT. It was found that seven out these 20 plans were rejected as they crossed the set tolerance criteria using DVH band as an evaluation tool.ConclusionsDVH band in photon therapy can help the clinician visualise the impact of setup errors at planning and may help select the plan with lesser influence of setup errors over another.
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Rosewall T, Wheat J, Currie G, Kong V, Bayley AJ, Moseley J, Chung P, Catton C, Craig T, Milosevic M. Planned versus 'delivered' bladder dose reconstructed using solid and hollow organ models during prostate cancer IMRT. Radiother Oncol 2016; 119:417-22. [PMID: 27072936 DOI: 10.1016/j.radonc.2016.03.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 03/11/2016] [Accepted: 03/13/2016] [Indexed: 10/22/2022]
Abstract
BACKGROUND AND PURPOSE All studies to date have evaluated the dosimetric effect of bladder deformation using an organ model that includes the dose to the urine. This research reconstructed bladder dose using both hollow and solid organ models, to determine if dose/volume differences exist. MATERIALS AND METHODS 35 prostate IMRT patients were selected, who had received 78Gy in 39 fractions and full bladder instructions. Biomechanical modelling and finite element analysis were used to reconstruct bladder dose (solid and hollow organ model) using every third CBCT throughout the treatment course. RESULTS Reconstructed dose (ReconDose) was 11.3Gy greater than planned dose (planDose) with a hollow bladder model (p<0.001) and 12.3Gy greater with a solid bladder model (p<0.0001). Median reconstructed volumes within the 30Gy, 65Gy and 78Gy isodoses were 3-4 times larger with the solid organ model (p<0.0001). The difference between planning bladder volume and median treatment volume was associated with the difference between the planDose and reconDose below 78Gy (R(2)>0.61). CONCLUSIONS Substantial differences exist between planned and reconstructed bladder dose, associated with the differences in bladder filling between planning and treatment. Dose reconstructed using a solid bladder model over-reports the volume of bladder within key isodose levels and overestimates the differences between planned and reconstructed dose. Dose reconstruction with a hollow organ model is recommended if the goal is to associate that dose with toxicity.
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Affiliation(s)
- Tara Rosewall
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada; Faculty of Science, Charles Sturt University, Australia.
| | - Janelle Wheat
- Faculty of Science, Charles Sturt University, Australia; Faculty of Medicine and Health Sciences, Macquarie University, Australia
| | - Geoffrey Currie
- Faculty of Science, Charles Sturt University, Australia; Faculty of Medicine and Health Sciences, Macquarie University, Australia
| | - Vickie Kong
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
| | - Andrew J Bayley
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada
| | - Joanne Moseley
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
| | - Peter Chung
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada
| | - Charles Catton
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada
| | - Tim Craig
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada
| | - Michael Milosevic
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada
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Njeh CF, Parker BC, Orton CG. Point/Counterpoint. Evaluation of treatment plans using target and normal tissue DVHs is no longer appropriate. Med Phys 2016; 42:2099-102. [PMID: 25979004 DOI: 10.1118/1.4903902] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Christopher F Njeh
- California Cancer Center, Fresno, California 93720 (Tel: 903-422-0449; E-mail: )
| | - Brent C Parker
- Department of Radiation Oncology, University of Texas Medical Branch at Galveston, Galveston, Texas 77555-0711 (Tel: 409-772-6560; E-mail: )
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Srivastava SP, Cheng CW, Das IJ. The effect of slice thickness on target and organs at risk volumes, dosimetric coverage and radiobiological impact in IMRT planning. Clin Transl Oncol 2015; 18:469-79. [DOI: 10.1007/s12094-015-1390-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 08/17/2015] [Indexed: 12/31/2022]
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Park SH, Kim JC, Lee JE, Park IK. Virtual lymph node analysis to evaluate axillary lymph node coverage provided by tangential breast irradiation. Radiat Oncol J 2015; 33:50-6. [PMID: 25874178 PMCID: PMC4394069 DOI: 10.3857/roj.2015.33.1.50] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 02/24/2015] [Accepted: 03/02/2015] [Indexed: 11/03/2022] Open
Abstract
PURPOSE To investigate the coverage of axillary lymph node with tangential breast irradiation fields by using virtual lymph node (LN) analysis. MATERIALS AND METHODS Forty-eight women who were treated with whole breast irradiation after breast-conserving surgery were analyzed. The axillary and breast volumes were delineated according to the Radiation Therapy Oncology Group (RTOG) contouring atlas. To generate virtual LN contours, preoperative fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) scans with identifiable LN were fused with the CT scans, and the virtual LN contour were delineated on the CT. RESULTS The median level I and II axillary volume coverage percentages at the VD95% line were 33.5% (range, 5.3% to 90.4%) and 0.6% (range, 0.0% to 14.6%), respectively. Thirty-one LNs in 18 patients were delineated (26 in level I and 5 in level II). In the level I axilla, 84.6% of virtual LNs were encompassed by the 95% isodose line. In the level II axilla, by contrast, none of the virtual LNs were encompassed by the 95% isodose volumes. There was a substantial discrepancy between the RTOG contouring atlas-based axillary volume analysis and the virtual LN analysis, especially for the level I axillary coverage. The axillary volume coverage was associated with the body mass index (BMI) and breast volume. CONCLUSION The tangential breast irradiation did not deliver adequate therapeutic doses to the axillary region, particularly those in the level II axilla. Patients with small breast volumes or lower BMI showed reduced axillary coverage from the tangential breast fields. For axillary LN irradiation, individualized anatomy-based radiation fields for patients would be necessary.
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Affiliation(s)
- Shin-Hyung Park
- Department of Radiation Oncology, Kyungpook National University Hospital, Daegu, Korea
| | - Jae-Chul Kim
- Department of Radiation Oncology, Kyungpook National University Hospital, Daegu, Korea
| | - Jeong Eun Lee
- Department of Radiation Oncology, Kyungpook National University Hospital, Daegu, Korea
| | - In-Kyu Park
- Department of Radiation Oncology, Kyungpook National University Hospital, Daegu, Korea
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Jin X, Yi J, Zhou Y, Yan H, Han C, Xie C. A new plan quality index for nasopharyngeal cancer SIB IMRT. Phys Med 2014; 30:122-7. [DOI: 10.1016/j.ejmp.2013.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 03/20/2013] [Accepted: 03/25/2013] [Indexed: 11/29/2022] Open
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Transformation of physical DVHs to radiobiologically equivalent ones in hypofractionated radiotherapy analyzing dosimetric and clinical parameters: a practical approach for routine clinical practice in radiation oncology. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2013; 2013:713420. [PMID: 24348743 PMCID: PMC3852578 DOI: 10.1155/2013/713420] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 08/18/2013] [Accepted: 09/26/2013] [Indexed: 11/17/2022]
Abstract
Purpose. The purpose of this study was to transform DVHs from physical to radiobiological ones as well as to evaluate their reliability by correlations of dosimetric and clinical parameters for 50 patients with prostate cancer and 50 patients with breast cancer, who were submitted to Hypofractionated Radiotherapy. Methods and Materials. To achieve this transformation, we used both the linear-quadratic model (LQ model) and the Niemierko model. The outcome of radiobiological DVHs was correlated with acute toxicity score according to EORTC/RTOG criteria. Results. Concerning the prostate radiotherapy, there was a significant correlation between RTOG acute rectal toxicity and D50 (P < 0.001) and V60 (P = 0.001) dosimetric parameters, calculated for α/β = 10 Gy. Moreover, concerning the breast radiotherapy there was a significant correlation between RTOG skin toxicity and V≥60 dosimetric parameter, calculated for both α/β = 2.3 Gy (P < 0.001) and α/β = 10 Gy (P < 0.001). The new tool seems reliable and user-friendly. Conclusions. Our proposed model seems user-friendly. Its reliability in terms of agreement with the presented acute radiation induced toxicity was satisfactory. However, more patients are needed to extract safe conclusions.
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Mayo CS, Zankowski C, Herman M, Miller R, Olivier K, Vincent A, Suominen J. A method to vectorize the dose distribution, the dose volume histogram and create a dose vector histogram. Med Phys 2012; 40:011717. [DOI: 10.1118/1.4769111] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Prabhakar R, Rath GK. A simple plan evaluation index based on the dose to critical structures in radiotherapy. J Med Phys 2012; 36:192-7. [PMID: 22228927 PMCID: PMC3249729 DOI: 10.4103/0971-6203.89965] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 02/28/2011] [Accepted: 05/17/2011] [Indexed: 12/25/2022] Open
Abstract
The dose to critical structures plays a very important role in treatment plan evaluation and forms a major challenging parameter in radiotherapy treatment planning. In this study, a simple index, Plan Normal tissue complication Index (PNI) has been proposed for treatment plan evaluation based on the dose to surrounding critical structures. To demonstrate the proposed index, four different critical treatment sites that include the prostate, upper abdominal cancer, lung, and head and neck were selected for this study. A software progam (PNIcalc) has been developed to compute the PNI from the exported dose-volume histogram data and from the tissue tolerance data published by Emami et al. and Kehwar et al. The software also shows the parameters that exceed the threshold limits of dose-volume parameters presented in the QUANTEC recommendations (2010). In all the studied cases, PNI gave an overall picture of the dose received by the critical structures and also indicate the fractional volume exceeding the tolerance limit. The proposed index, PNI gives a quick comparison and selection of treatment plans that result in reduced dose to the critical structures. It can be used as an additional tool for routine treatment plan evaluation in external beam radiotherapy.
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Affiliation(s)
- Ramachandran Prabhakar
- Department of Radiation Oncology, Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India
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Rosewall T, Bayley AJ, Chung P, Le LW, Xie J, Baxi S, Catton CN, Currie G, Wheat J, Milosevic M. The effect of delineation method and observer variability on bladder dose-volume histograms for prostate intensity modulated radiotherapy. Radiother Oncol 2011; 101:479-85. [PMID: 21864921 DOI: 10.1016/j.radonc.2011.06.039] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 06/17/2011] [Accepted: 06/18/2011] [Indexed: 11/16/2022]
Abstract
PURPOSE To quantify the effect of delineation method on bladder DVH, observer variability (OV) and contouring time for prostate IMRT plans. MATERIALS AND METHODS Planning CT scans and IMRT plans of 30 prostate cancer patients were anonymized. For 20 patients, 1 observer delineated the bladder using 9 methods. The effect of delineation method on the DVH curve, discrete dose levels and delineation time was quantified. For the 10 remaining CTs, 6 observers delineated bladder wall using 4 methods. Observer-based volume variation and intraclass correlation coefficient (ICC) were used to describe the dosimetric effects of OV. RESULTS Manual delineation of the bladder wall (BW_m) was significantly slower than any other method (mean: 20 min vs. ≤ 13 min) and the dosimetric effect of OV was significantly larger (V70 Gy ICC: 0.78 vs. 0.98). Only volumes created using a 2.5mm contraction from the outer surface, and a method providing a consistent wall volume, showed no notable dosimetric differences from BW_m in both absolute and relative volume. CONCLUSIONS Automatic contractions from the outer surface provide quicker, more reproducible and reasonably accurate substitutes for BW_m. The widespread use of automatic contractions to create a bladder wall volume would assist in the consistent application of IMRT dose constraints and the interpretation of reported dose.
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Affiliation(s)
- Tara Rosewall
- Princess Margaret Hospital and Department of Radiation Oncology, University of Toronto, Canada.
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20
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Radiobiological evaluation of the influence of dwell time modulation restriction in HIPO optimized HDR prostate brachytherapy implants. J Contemp Brachytherapy 2010; 2:117-128. [PMID: 27853473 PMCID: PMC5104831 DOI: 10.5114/jcb.2010.16923] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 09/01/2010] [Indexed: 12/25/2022] Open
Abstract
Purpose One of the issues that a planner is often facing in HDR brachytherapy is the selective existence of high dose volumes around some few dominating dwell positions. If there is no information available about its necessity (e.g. location of a GTV), then it is reasonable to investigate whether this can be avoided. This effect can be eliminated by limiting the free modulation of the dwell times. HIPO, an inverse treatment plan optimization algorithm, offers this option. In treatment plan optimization there are various methods that try to regularize the variation of dose non-uniformity using purely dosimetric measures. However, although these methods can help in finding a good dose distribution they do not provide any information regarding the expected treatment outcome as described by radiobiology based indices. Material and methods The quality of 12 clinical HDR brachytherapy implants for prostate utilizing HIPO and modulation restriction (MR) has been compared to alternative plans with HIPO and free modulation (without MR). All common dose-volume indices for the prostate and the organs at risk have been considered together with radiobiological measures. The clinical effectiveness of the different dose distributions was investigated by calculating the response probabilities of the tumors and organs-at-risk (OARs) involved in these prostate cancer cases. The radiobiological models used are the Poisson and the relative seriality models. Furthermore, the complication-free tumor control probability, P+ and the biologically effective uniform dose (D¯¯) were used for treatment plan evaluation and comparison. Results Our results demonstrate that HIPO with a modulation restriction value of 0.1-0.2 delivers high quality plans which are practically equivalent to those achieved with free modulation regarding the clinically used dosimetric indices. In the comparison, many of the dosimetric and radiobiological indices showed significantly different results. The modulation restricted clinical plans demonstrated a lower total dwell time by a mean of 1.4% that was proved to be statistically significant (p = 0.002). The HIPO with MR treatment plans produced a higher P+ by 0.5%, which stemmed from a better sparing of the OARs by 1.0%. Conclusions Both the dosimetric and radiobiological comparison shows that the modulation restricted optimization gives on average similar results with the optimization without modulation restriction in the examined clinical cases. Concluding, based on our results, it appears that the applied dwell time regularization technique is expected to introduce a minor improvement in the effectiveness of the optimized HDR dose distributions.
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Zhao B, Joiner MC, Orton CG, Burmeister J. “SABER”: A new software tool for radiotherapy treatment plan evaluation. Med Phys 2010; 37:5586-92. [DOI: 10.1118/1.3497152] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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22
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Chow JCL, Markel D, Jiang R. Technical Note: Calculation of normal tissue complication probability using Gaussian error function model. Med Phys 2010; 37:4924-9. [DOI: 10.1118/1.3483097] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Prabhakar R, Rath GK. Slice-based plan evaluation methods for three dimensional conformal radiotherapy treatment planning. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2010; 32:233-9. [PMID: 20169843 DOI: 10.1007/bf03179244] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dose volume histograms (DVHs) play a vital role in determining the optimal plan for radiotherapy treatment delivery. The current concepts of conformality index (CI), equivalent uniform dose (EUD) derived from dose volume histogram (DVH) does not provide any spatial information. In this study, slice-based evaluation methods have been proposed for spatially analyzing the radiotherapy treatment plans. A case of prostate cancer has been selected for demonstrating the proposed tools for evaluating the dose distribution. Three dimensional conformal radiotherapy treatment planning (3D-CRT) was performed to a dose of 27 Gy/15# with three fields (6 MV anteroposterior and two 15 MV lateral fields) employing multileaf collimator after delivering 45 Gy/25#. The dose was normalized to isocenter and the treatment plan was evaluated with DVH. The dose maximum point, conformality index, planning target volume coverage index (PCI), planning target volume overdose index (POI) and equivalent uniform dose (EUD) were evaluated for every single slice along the cranio-caudal direction for all the planning target volume (PTV) contours and plotted against the slice location. The dose maximum point plotted against the slice position helps in identifying the slices where the dose maximum point is outside the target volume. The plot of conformality index gives the information about the location of those slices where excess of surrounding normal tissues is encompassed inside the prescription isodose. POI quantifies the high dose regions inside the PTV slices that receive doses above 107% of the prescription dose. Similarly, the plot of PCI and EUD with slice position gives the information about those slices where the tumor is not covered adequately. The proposed methods in this study forms as a simpler way to assess the spatial distribution of the dose inside the target volume. It could be used in combination with the current plan evaluation tools and will be very helpful in analyzing the treatment plans.
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Affiliation(s)
- R Prabhakar
- Department of Radiation Oncology, Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India.
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Pyakuryal A, Myint WK, Gopalakrishnan M, Jang S, Logemann JA, Mittal BB. A computational tool for the efficient analysis of dose-volume histograms from radiation therapy treatment plans. J Appl Clin Med Phys 2010. [PMID: 20160690 PMCID: PMC2897015 DOI: 10.1120/jacmp.v11i1.3013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
A Histogram Analysis in Radiation Therapy (HART) program was primarily developed to increase the efficiency and accuracy of dose–volume histogram (DVH) analysis of large quantities of patient data in radiation therapy research. The program was written in MATLAB to analyze patient plans exported from the treatment planning system (Pinnacle3) in the American Association of Physicists in Medicine/Radiation Therapy Oncology Group (AAPM/RTOG) format. HART‐computed DVH data was validated against manually extracted data from the planning system for five head and neck cancer patients treated with the intensity‐modulated radiation therapy (IMRT) technique. HART calculated over 4000 parameters from the differential DVH (dDVH) curves for each patient in approximately 10–15 minutes. Manual extraction of this amount of data required 5 to 6 hours. The normalized root mean square deviation (NRMSD) for the HART–extracted DVH outcomes was less than 1%, or within 0.5% distance‐to‐agreement (DTA). This tool is supported with various user‐friendly options and graphical displays. Additional features include optimal polynomial modeling of DVH curves for organs, treatment plan indices (TPI) evaluation, plan‐specific outcome analysis (POA), and spatial DVH (zDVH) and dose surface histogram (DSH) analyses, respectively. HART is freely available to the radiation oncology community. PACS numbers: 87.53.‐j; 87.53.Tf; 87.53.Xd.
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Affiliation(s)
- Anil Pyakuryal
- Department of Radiation Oncology, Northwestern Memorial Hospital, Chicago, Illinois, USA.
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Das IJ, Cheng CW, Chopra KL, Mitra RK, Srivastava SP, Glatstein E. Intensity-Modulated Radiation Therapy Dose Prescription, Recording, and Delivery: Patterns of Variability Among Institutions and Treatment Planning Systems. ACTA ACUST UNITED AC 2008; 100:300-7. [PMID: 18314476 DOI: 10.1093/jnci/djn020] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Indra J Das
- Department of Radiation Oncology, University of Pennsylvania, 2 Donner Bldg, 3400 Spruce St, Philadelphia, PA 19104, USA.
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Marks LB, Ma J. Challenges in the clinical application of advanced technologies to reduce radiation-associated normal tissue injury. Int J Radiat Oncol Biol Phys 2007; 69:4-12. [PMID: 17707263 DOI: 10.1016/j.ijrobp.2007.05.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 05/07/2007] [Accepted: 05/07/2007] [Indexed: 11/21/2022]
Affiliation(s)
- Lawrence B Marks
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
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Jereczek-Fossa BA, Cattani F, D'Onofrio A, Cambria R, Kowalczyk A, Corallo A, Vavassori A, Zerini D, Ivaldi GB, DeCobelli O, Orecchia R. Dose distribution in 3-dimensional conformal radiotherapy for prostate cancer: Comparison of two treatment techniques (six coplanar fields and two dynamic arcs). Radiother Oncol 2006; 81:294-302. [PMID: 17113670 DOI: 10.1016/j.radonc.2006.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 09/15/2006] [Accepted: 10/03/2006] [Indexed: 11/16/2022]
Abstract
PURPOSE To compare dose distribution for two techniques of 3-dimensional conformal radiotherapy (RT): 6-field technique (6F) and 2-dynamic arc therapy (2DA). METHODS AND MATERIALS Thirty nonmetastatic prostate cancer patients were included. In each patient, two treatment plans were prepared: with six coplanar fields (45 degrees , 90 degrees , 135 degrees , 225 degrees , 270 degrees , 315 degrees ) and with two dynamic lateral 100 degrees -wide arcs (40-140 degrees , 220-320 degrees ). Dose-volume histograms (DVHs) were computed and mean area under curve (AUC) values were calculated for the DVHs of Planning Target Volume (PTV), rectum, urinary bladder and femoral heads. Doses given to 30% of rectum (DR(30)), to 60% of rectum (DR(60)), to 50% of bladder (DB(50)), to 50% of femoral head (DF(50)) and to 95% of PTV (DPTV(95)) were reported as a percentage of the total dose. RESULTS Mean DR(30) and DR(60) for 6F and 2DA were 75.8%, 51.5% and 72.2%, 37.2%, respectively. Mean DB(50) for 6F and 2DA were 68% and 64.2%, respectively. Mean right DF(50) for 6F and 2DA were 35.4% and 45.5%, respectively. Mean DPTV(95) for 6F and 2DA were 99% and 99.2%, respectively. Mean AUCs of DVHs of rectum and urinary bladder were significantly higher for 6F (this was more evident for small PTV and in the intermediate dose range). Mean AUC of DVHs of PTV and femoral heads were significantly higher for 2DA. CONCLUSIONS Both 6F and 2DA offer good dose distribution for PTV. 2DA allows for significantly better sparing of rectum and urinary bladder with slightly worse femoral head dose distribution. Further study is warranted in order to establish the clinical relevance of these differences.
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Luo C, Yang CC, Narayan S, Stern RL, Perks J, Goldberg Z, Ryu J, Purdy JA, Vijayakumar S. Use of benchmark dose–volume histograms for selection of the optimal technique between three-dimensional conformal radiation therapy and intensity-modulated radiation therapy in prostate cancer. Int J Radiat Oncol Biol Phys 2006; 66:1253-62. [PMID: 17145540 DOI: 10.1016/j.ijrobp.2006.06.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Revised: 06/04/2006] [Accepted: 06/06/2006] [Indexed: 11/28/2022]
Abstract
PURPOSE The aim of this study was to develop and validate our own benchmark dose-volume histograms (DVHs) of bladder and rectum for both conventional three-dimensional conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy (IMRT), and to evaluate quantitatively the benefits of using IMRT vs. 3D-CRT in treating localized prostate cancer. METHODS AND MATERIALS During the implementation of IMRT for prostate cancer, our policy was to plan each patient with both 3D-CRT and IMRT. This study included 31 patients with T1b to T2c localized prostate cancer, for whom we completed double-planning using both 3D-CRT and IMRT techniques. The target volumes included prostate, either with or without proximal seminal vesicles. Bladder and rectum DVH data were summarized to obtain an average DVH for each technique and then compared using two-tailed paired t test analysis. RESULTS For 3D-CRT our bladder doses were as follows: mean 28.8 Gy, v60 16.4%, v70 10.9%; rectal doses were: mean 39.3 Gy, v60 21.8%, v70 13.6%. IMRT plans resulted in similar mean dose values: bladder 26.4 Gy, rectum 34.9 Gy, but lower values of v70 for the bladder (7.8%) and rectum (9.3%). These benchmark DVHs have resulted in a critical evaluation of our 3D-CRT techniques over time. CONCLUSION Our institution has developed benchmark DVHs for bladder and rectum based on our clinical experience with 3D-CRT and IMRT. We use these standards as well as differences in individual cases to make decisions on whether patients may benefit from IMRT treatment rather than 3D-CRT.
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Affiliation(s)
- Chunhui Luo
- Radiation Oncology, University of California Davis Medical Center, Sacramento, CA 95817, USA
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Yoon M, Shin D, Park J, Park SY, Lee SB, Kim JY, Kim TH, Kim DY, Cho KH. A new evaluation method of target volume coverage and homogeneity for IMRT treatment planning. Phys Med 2006; 22:43-51. [PMID: 17643891 DOI: 10.1016/s1120-1797(06)80052-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Revised: 02/22/2006] [Accepted: 04/26/2006] [Indexed: 11/23/2022] Open
Abstract
Based on the functional approximation of a target volume DVH (TV-DVH) to a modified step function, we propose a new index that indicates the degrees of dose coverage and homogeneity for target volume reached in clinical routines. Forty-seven IMRT patient plans are included in the analysis to explore the efficiency of the proposed method. The new index, named s-index, was defined to vary from 0:05 for clinically acceptable TV-DVH at our institution and showed the ability to give the user an idea whether the degree of dose coverage and homogeneity for target volume were adequate when the user-defined criteria had been in place. The result shows that the lower value of s-index indecates the higher dose coverage for the tumor volume and/or the higher dose homogeneity showing the faster fall-off rate at the percentage dose higher than 100%. In addition to the quantification of dose coverage and homogeneity is has been also shown that s-index is more accurate in evaluating the dose homogeneity in tumor volume than the conventional method. The proposed method has demonstrated the effectiveness in evaluating TV-DVH in terms of simple index and supplements currently used indices by providing complete information of a DVH curve in a treatment plan.
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Court LE, Dong L, Lee AK, Cheung R, Bonnen MD, O'Daniel J, Wang H, Mohan R, Kuban D. An automatic CT-guided adaptive radiation therapy technique by online modification of multileaf collimator leaf positions for prostate cancer. Int J Radiat Oncol Biol Phys 2005; 62:154-63. [PMID: 15850916 DOI: 10.1016/j.ijrobp.2004.09.045] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2003] [Revised: 09/02/2004] [Accepted: 09/07/2004] [Indexed: 10/25/2022]
Abstract
PURPOSE To propose and evaluate online adaptive radiation therapy (ART) using in-room computed tomography (CT) imaging that detects changes in the target position and shape of the prostate and seminal vesicles (SVs) and then automatically modifies the multileaf collimator (MLC) leaf pairs in a slice-by-slice fashion. METHODS AND MATERIALS For intensity-modulated radiation therapy (IMRT) using a coplanar beam arrangement, each MLC leaf pair projects onto a specific anatomic slice. The proposed strategy assumes that shape deformation is a function of only the superior-inferior (SI) position. That is, there is no shape change within a CT slice, but each slice can be displaced in the anteroposterior (AP) or right-left (RL) direction relative to adjacent slices. First, global shifts (in SI, AP, and RL directions) were calculated by three-dimensional (3D) registration of the bulk of the prostate in the treatment planning CT images with the daily CT images taken immediately before treatment. Local shifts in the AP direction were then found using slice-by-slice registration, in which the CT slices were individually registered. The translational shift within a slice could then be projected to a translational shift in the position of the corresponding MLC leaf pair for each treatment segment for each gantry angle. Global shifts in the SI direction were accounted for by moving the open portal superiorly or inferiorly by an integral number of leaf pairs. The proposed slice-by-slice registration technique was tested by using daily CT images from 46 CT image sets (23 each from 2 patients) taken before the standard delivery of IMRT for prostate cancer. A dosimetric evaluation was carried out by using an 8-field IMRT plan. RESULTS The shifts and shape change of the prostate and SVs could be separated into 3D global shifts in the RL, AP, and SI directions, plus local shifts in the AP direction, which were different for each CT slice. The MLC leaf positions were successfully modified to compensate for these global shifts and local shape variations. The ART method improved geometric coverage of the prostate and SVs compared with the couch-shift method, particularly for the superior part of the prostate and all the SVs, for which the interfraction shape change was the largest. The dosimetric comparison showed that the ART method covered the target better and reduced the rectal dose more than a simple couch-translation method. CONCLUSIONS ART corrected for interfraction changes in the position and shape of the prostate and SVs and gave dose distributions that were considerably closer to the planned dose distributions than could be achieved with simple alignment strategies that neglect shape change. The ART proposed in this investigation requires neither contouring of the daily CT images nor extensive calculations; therefore, it may prove to be an effective and clinically practical solution to the problem of interfraction shape changes.
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Affiliation(s)
- Laurence E Court
- Department of Radiation Physics, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
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Heufelder J, Zink K, Scholz M, Kramer KD, Welker K. [A method of computerized evaluation of CT based treatment plants in external radiotherapy]. Z Med Phys 2004; 13:231-9. [PMID: 14732952 DOI: 10.1078/0939-3889-00175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Selection of an optimal treatment plan requires the comparison of dose distributions and dose-volume histograms (DVH) of all plan variants calculated for the patient. Each treatment plan consists generally of 30 to 40 CT slices, making the comparison difficult and time consuming. The present study proposes an objective index that takes into account both physical and biological criteria for the evaluation of the dose distribution. The DHV-based evaluation index can be calculated according to the following four criteria: ICRU conformity (review of the differences between the dose in the planning target volume and the ICRU recommendations); mean dose and dose homogeneity of the planning target volume; the product of tumour complication probability (TCP) and normal tissue complication probability (NTCP); and finally a criterion that takes into account the dose load of non-segmented tissue portions within the CT slice. The application of the objective index is demonstrated for two different clinical cases (esophagus and breast carcinoma). During the evaluation period, the objective index showed a good correlation between the doctor's decision and the proposed objective index. Thus, the objective index is suitable for a computer-based evaluation of treatment plans.
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Greco C, Mazzetta C, Cattani F, Tosi G, Castiglioni S, Fodor A, Orecchia R. Finding dose–volume constraints to reduce late rectal toxicity following 3D-conformal radiotherapy (3D-CRT) of prostate cancer. Radiother Oncol 2003; 69:215-22. [PMID: 14643961 DOI: 10.1016/j.radonc.2003.08.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND AND PURPOSE The rectum is known to display a dose-volume effect following high-dose 3D-conformal radiotherapy (3D-CRT). The aim of the study is to search for significant dose-volume combinations with the specific treatment technique and patient set-up currently used in our institution. PATIENTS AND METHODS We retrospectively analyzed the dose-volume histograms (DVH) of 135 patients with stage T1b-T3b prostate cancer treated consecutively with 3D-CRT between 1996 and 2000 to a total dose of 76 Gy. The median follow-up was 28 months (range 12-62). All late rectal complications were scored using RTOG criteria. Time to late toxicity was assessed using the Kaplan-Meyer method. The association between variables at baseline and > or=2 rectal toxicity was tested using chi(2) test or Fisher's exact test. A multivariate analysis using logistic regression was performed. RESULTS Late rectal toxicity grade > or=2 was observed in 24 of the 135 patients (17.8%). A 'grey area' of increased risk has been identified. Average DVHs of the bleeding and non-bleeding patients were generated. The area under the percent volume DVH for the rectum of the bleeding patients was significantly higher than that of patients without late rectal toxicity. On multivariate analysis the correlation between the high risk DVHs and late rectal bleeding was confirmed. CONCLUSIONS The present analysis confirms the role of the rectal DVH as a tool to discriminate patients undergoing high-dose 3D-CRT into a low and a high risk of developing late rectal bleeding. Based on our own results and taking into account the data published in the literature, we have been able to establish new dose-volume constraints for treatment planning: if possible, the percentage of rectal volume exposed to 40, 50, 60, 72 and 76 Gy should be limited to 60, 50, 25, 15 and 5%, respectively.
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Affiliation(s)
- Carlo Greco
- Division of Radiation Oncology, European Institute of Oncology, Via Ripamonti 435, Milan 2014, Italy.
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Chao KSC, Blanco AI, Dempsey JF. A conceptual model integrating spatial information to assess target volume coverage for IMRT treatment planning. Int J Radiat Oncol Biol Phys 2003; 56:1438-49. [PMID: 12873690 DOI: 10.1016/s0360-3016(03)00429-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE We propose a model that integrates the spatial location of each voxel within a clinical target volume (CTV) to differentiate the merit of intensity-modulated radiation therapy (IMRT) plans with similar dose-volume histogram (DVH). This conceptual model is based on the hypothesis that various subregions within a given CTV that may carry different degree of risk in containing microscopic disease. METHODS AND MATERIALS We hypothesize that a correlation between the probability of microscopic tumor extension and the risk of lymph node metastasis of a particular voxel point within CTV can be inferred based on its distance from the surface of radiographically evident gross disease. A preliminary observation was gathered from existing clinicopathologic data, and, based on these observations, a conceptual model for exponential-decay microscopic-extension probability function around primary tumor and linear function parameters relating the likelihood of lymph node metastasis to the distance from primary tumor was proposed. This model was generated to provide scoring functions to examine the merit of IMRT plans. To test the feasibility of this model, we generated two IMRT plans with similar and clinically acceptable DVH-based CTV coverage. Planning data were transferred to a data analysis software package (Matlab, The Mathworks Inc.). A 3D scoring function was calculated for each voxel inside the CTV. The adequacy of target coverage was evaluated by several novel approaches: 2D dose-volume scoring-function histograms (DVSH), the integral probability of relative residual tumor burden (RRTB), and tumor control probabilities (TCP) employing the scoring function as a pseudo-clonogen density distribution. RESULTS Incorporating parameters for the risk of containing microscopic disease in each voxel into the scoring function algorithm, 2D DVSHs, RRTBs, integral RRTBs, and TCPs were computed. On each axial image, an RRTB map could locate the regions at greatest risk. These scoring functions were able to differentiate the merit of CTV coverage of clinically different IMRT plans but having very similar DVHs; one with cold spots centrally located over the gross tumor, and the other with more acceptable cold spots on the periphery of the CTV further away from the gross tumor volume. CONCLUSIONS We demonstrated the feasibility and potential utility of an IMRT scoring method derived from this conceptual modeling approach. These methods are capable of ranking treatment plans with similar DVH profiles but different underdosed regions within the target. We will examine the accuracy of model parameters by performing tumor-specific image-pathologic correlation studies. Upon validation of these parameters, incorporating this scoring function model into plan optimization may have the potential to avoid underdosing subvolumes within CTV that harbor a higher likelihood of microscopic disease.
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Affiliation(s)
- K S Clifford Chao
- Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
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Jani AB, Hand CM, Pelizzari CA, Roeske JC, Krauz L, Vijayakumar S. Biological-effective versus conventional dose volume histograms correlated with late genitourinary and gastrointestinal toxicity after external beam radiotherapy for prostate cancer: a matched pair analysis. BMC Cancer 2003; 3:16. [PMID: 12744725 PMCID: PMC156635 DOI: 10.1186/1471-2407-3-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2002] [Accepted: 05/13/2003] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND To determine whether the dose-volume histograms (DVH's) for the rectum and bladder constructed using biological-effective dose (BED-DVH's) better correlate with late gastrointestinal (GI) and genitourinary (GU) toxicity after treatment with external beam radiotherapy for prostate cancer than conventional DVH's (C-DVH's). METHODS The charts of 190 patients treated with external beam radiotherapy with a minimum follow-up of 2 years were reviewed. Six patients (3.2%) were found to have RTOG grade 3 GI toxicity, and similarly 6 patients (3.2%) were found to have RTOG grade 3 GU toxicity. Average late C-DVH's and BED-DVH's of the bladder and rectum were computed for these patients as well as for matched-pair control patients. For each matched pair the following measures of normalized difference in the DVH's were computed: (a) deltaAUC = (Area Under Curve [AUC] in grade 3 patient--AUC in grade 0 patient)/(AUC in grade 0 patient) and (b) deltaV60 = (Percent volume receiving = 60 Gy [V60] in grade 3 patient--V60 in grade 0 patient)/(V60 in grade 0 patient). RESULTS As expected, the grade 3 curve is to the right of and above the grade 0 curve for all four sets of average DVH's--suggesting that both the C-DVH and the BED-DVH can be used for predicting late toxicity. deltaAUC was higher for the BED-DVH's than for the C-DVH's--0.27 vs 0.23 (p = 0.036) for the rectum and 0.24 vs 0.20 (p = 0.065) for the bladder. deltaV60 was also higher for the BED-DVH's than for the C-DVH's--2.73 vs 1.49 for the rectum (p = 0.021) and 1.64 vs 0.71 (p = 0.021) for the bladder. CONCLUSIONS When considering well-established dosimetric endpoints used in evaluating treatment plans, BED-DVH's for the rectum and bladder correlate better with late toxicity than C-DVH's and should be considered when attempting to minimize late GI and GU toxicity after external beam radiotherapy for prostate cancer.
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Affiliation(s)
- Ashesh B Jani
- Department of Radiation and Cellular Oncology, University of Chicago Hospitals, Chicago, USA
| | - Christopher M Hand
- Department of Radiation and Cellular Oncology, University of Chicago Hospitals, Chicago, USA
| | - Charles A Pelizzari
- Department of Radiation and Cellular Oncology, University of Chicago Hospitals, Chicago, USA
| | - John C Roeske
- Department of Radiation and Cellular Oncology, University of Chicago Hospitals, Chicago, USA
| | - Lani Krauz
- Department of Radiation and Cellular Oncology, University of Chicago Hospitals, Chicago, USA
| | - Srinivasan Vijayakumar
- Department of Radiation and Cellular Oncology, University of Chicago Hospitals, Chicago, USA
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Donovan EM, Bleackley NJ, Evans PM, Reise SF, Yarnold JR. Dose-position and dose-volume histogram analysis of standard wedged and intensity modulated treatments in breast radiotherapy. Br J Radiol 2002; 75:967-73. [PMID: 12515705 DOI: 10.1259/bjr.75.900.750967] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The aim of this work was to evaluate the positional distribution of dose in a concise manner and to analyse dose-histogram results in tangential breast radiotherapy in 300 patients, randomized to standard wedged or intensity modulated radiotherapy (IMRT), for future correlation with clinical outcome data. A simple method for analysing the dose-position relationship in the treatment volume was used to compare the spatial distribution of dose in patients. The breast was divided into equal thirds (upper, middle and lower) and dose was assessed using three dose bands; 95-105%, >105-110% and >110% of the prescription dose. The effect of using IMRT on the dosimetry was assessed from dose-volume histogram data using the following parameters: percentage of the target volume receiving a dose less than 95%, greater than 105%, either less than 95% or greater than 105% of that prescribed; the mean dose; and the maximum dose. Doses greater than 105% were predominantly in the upper and lower regions of the breast in the standard wedged treatment. 96% of these patients received doses greater than 105% in the upper region of the breast and 70% received doses greater than 105% in the lower breast. Only 4% of patients allocated IMRT received doses greater than 105% in either region. Analysis of dose-volume histogram data showed that IMRT reduced the volume receiving a dose greater than 105% by a mean of 10.7% (p= or <0.001); the mean change in the volume receiving a dose less than 95% was 0.2% (p=0.63). Average mean plan dose was 101.6% for standard treatment and 99.6% for IMRT (p<0.001 for each compared with 100.0% ideal). The mean value of maximum dose was reduced from 111% to 106% in the group of patients randomized to IMRT. A simple method for describing the relationship between dose and position in the breast, which is helpful for the effective correlation of dosimetry and clinical effects, is reported. Further, application of IMRT to the tangential field irradiation of the breast has been demonstrated to reduce high dose regions in both volume and dose level without compromising either minimum dose coverage or mean dose delivered to the breast.
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Affiliation(s)
- E M Donovan
- Joint Department of Physics, Royal Marsden NHS Trust and Institute of Cancer Research, Downs Road, Sutton, Surrey SM2 5PT, UK
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Holloway L, Hoban P, Metcalfe P. Radiobiological indices that consider volume: a review. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2002; 25:47-57. [PMID: 12219845 DOI: 10.1007/bf03178466] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Understanding and predicting the impact of any radiotherapy treatment is critical if patients are to receive treatment with a high likelihood of eliminating the tumour and low likelihood of complications. One of the major contributing factors in determining these effects is the volume treated. This review assesses the current use and accuracy of a series of models which consider volume, building on a previous review which investigated the impact of fractionation particularly with respect to the linear quadratic model. Volume is particularly important in assessing the overall effect with respect to destroying the clonogenic cells and preventing damage to the normal tissues. Dose volume histograms are one of the simplest and most useful forms of representing volume information, however it is difficult to correlate plans based only on DVHs. For this reason various reduction schemes have been introduced and tumour control probability and normal tissues complication probability models adjusted to use this information. Many of these models have proved quite useful in the clinic although they are limited by the available radiobiological data.
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Affiliation(s)
- L Holloway
- Department of Radiation Oncology, Liverpool Hospital, BC, NSW.
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Price RA, Hanks GE, McNeeley SW, Horwitz EM, Pinover WH. Advantages of using noncoplanar vs. axial beam arrangements when treating prostate cancer with intensity-modulated radiation therapy and the step-and-shoot delivery method. Int J Radiat Oncol Biol Phys 2002; 53:236-43. [PMID: 12007964 DOI: 10.1016/s0360-3016(02)02736-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE The focus of this work was to compare noncoplanar beam arrangements used for intensity-modulated radiation therapy (IMRT) step-and-shoot delivery to several axial beam arrangements used in the treatment of clinically localized prostate cancer. METHODS AND MATERIALS A 5-field coronal crossfire beam arrangement was developed for IMRT with the objective of improving upon the rectal and bladder dose-volume histograms obtained using 5-, 7-, and 9-field axial beam arrangements. Additionally, a modified 7-field crossfire technique was developed yielding improved dose distributions. The average values of dose-volume histograms and the time for treatment delivery were evaluated for all plans for 10 randomly chosen patients. RESULTS Both crossfire IMRT techniques exhibited a 15-25% decrease in dose to the hottest 10% and 20% of the rectum relative to all three axial IMRT techniques. The 5-field crossfire orientation yields slightly higher bladder doses when compared to the other techniques. In selected cases, the 7-field crossfire beam arrangement demonstrates decreased dose to the bladder when compared to all three axial techniques. A mean delivery time of 14 to 17.5 min is noted for the noncoplanar arrangements after positioning and localization. CONCLUSIONS A technique is described that allows additional normal tissue sparing during dose escalation to the prostate during IMRT delivery. This technique takes advantage of the spatial orientation between the prostate, rectum, and bladder. With patient setup and target localization time aside, a mean treatment time of 14 to 17.5 min allows the delivery of the crossfire plans to conform to standard treatment times.
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Affiliation(s)
- Robert A Price
- Department of Radiation Oncology, Fox Chase Cancer Center, 7701 Burholme Avenue, Philadelphia, PA 19111, USA.
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Lefkopoulos D, Foulquier JN, Petegnief Y, Touboul E. [Physical and methodological aspects of multimodality imaging and principles of treatment planning in 3D conformal radiotherapy]. Cancer Radiother 2001; 5:496-514. [PMID: 11715302 DOI: 10.1016/s1278-3218(01)00108-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The recent evolutions of the imaging modalities, the dose calculation models, the linear accelerators and the portal imaging permit to improve the quality of the conformal radiation therapy treatment planning. With DICOM protocols, the acquired imaging data coming from different modalities are treated by performant image fusion algorithms and yield more precise target volumes and organs at risk. The transformation of the clinical target volumes (CTV) to planning target volumes (PTV) can be realised using advanced probabilistic techniques based on clinical experience. The treatment plans evaluation is based on the dose volume histograms. Their precision and clinical relevance are improved by the multi-modality imaging and the advanced dose calculation models. The introduction of the inverse planning systems permitting to realise modulated intensity radiation therapy generates highly conformal dose distributions. All the previously cited complex techniques require the application of rigorous quality assurance programs.
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Affiliation(s)
- D Lefkopoulos
- Unité de physique médicale, service d'oncologie-radiothérapie, hôpital Tenon, 4, rue de la Chine, 75020 Paris, France
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Abstract
Data gathered from dose escalation protocols for the treatment of prostate cancers conducted in the past 10 years have shown that rectal toxicity can be controlled by the use of careful conformal techniques. The most severe complications of rectal irradiation (obstruction and fistula requiring colostomy) have been essentially eliminated. The most frequent gastrointestinal complications of conformal radiotherapy of prostate cancer are now rectal bleeding associated with telangiectatic changes to the vasculature of the submucosa, and in severe cases, ulceration requiring cautery procedures and or transfusion. The benefits of 3-dimensional conformal radiotherapy (3D-CRT) are strongly technique dependent, with a strong dose response for single techniques for prescription doses over 70 Gy. Studies of rectal motion show that the anterior wall can move approximately 1 cm during treatment, so portions of the anterior rectal wall will regularly receive the full prescription dose if posterior margin sizes >/= 1 cm are used in designing the planning target volume (PTV). There is strong evidence that increased rectal shielding and posterior PTV margin sizes approximately 0.6 cm reduce rectal complication rates. Despite uncertainties due to rectal motion, studies of dose-volume histograms (DVHs) show that rectal toxicity is strongly influenced by the percent volumes of rectal wall exposed to doses approximately 70 Gy and higher. Recent data suggests that percent volumes of rectal wall exposed doses between 40 to 50 Gy, and the existence of a reserve of unexposed tissue may also play a role in determining rectal bleeding rates.
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Affiliation(s)
- A Jackson
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York, NY 10021, USA
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Li S, DeWeese T, Lee DJ, Kleinberg L, Wharam M. A dose texture plot in a moving frame as a new planning tool for single-plane implants in HDR brachytherapy. Med Phys 2001; 28:97-103. [PMID: 11213927 DOI: 10.1118/1.1334607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A dose-texture plot is a print of dose values on the points of interest in a super-plane. The super-plane is a moving frame across the treatment depth-surface(s) with a fixed distance from surgical bed. The moving frame has an axis tangent to the midline of two neighboring catheters and the other axis perpendicular to the midline. By setting the scales of the two axes in units of the dwell step-size and the local distance between the two catheters, we can easily locate the basal-dose points with pairs of integers. A dose-texture plot on the basal-dose points in the super-plane provides the dose and location information in one picture. Such a picture can concisely represent the dose distribution in the treatment depth and allows us to quickly and quantitatively evaluate the effect of the source-dwell times and positions. This treatment-planning-evaluation tool has been used for development of an iteration optimization algorithm. The results of the iteration optimization on clinical cases demonstrated significant improvements over the optimization algorithms used in a commercial planning system.
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Affiliation(s)
- S Li
- Division of Radiation Oncology, Johns Hopkins Oncology Center, Baltimore, Maryland 21287, USA.
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