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Wegener D, Berger B, Outtagarts Z, Zips D, Paulsen F, Bleif M, Thorwarth D, Alber M, Dohm O, Müller AC. Prospective evaluation of probabilistic dose-escalated IMRT in prostate cancer. Radiol Oncol 2020; 55:88-96. [PMID: 33885246 PMCID: PMC7877263 DOI: 10.2478/raon-2020-0075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/02/2020] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Cure- and toxicity rates after intensity-modulated radiotherapy (IMRT) of prostate cancer are dose-and volume dependent. We prospectively studied the potential for organ at risk (OAR) sparing and compensation of tumor movement with the coverage probability (CovP) concept. PATIENTS AND METHODS Twenty-eight prostate cancer patients (median age 70) with localized disease (cT1c-2c, N0, M0) and intermediate risk features (prostate-specific antigen [PSA] < 20, Gleason score ≤ 7b) were treated in a prospective study with the CovP concept. Planning-CTs were performed on three subsequent days to capture form changes and movement of prostate and OARs. The clinical target volume (CTV) prostate and the OARs (bladder and rectum) were contoured in each CT. The union of CTV1-3 was encompassed by an isotropic margin of 7 mm to define the internal target volume (ITV). Dose prescription/escalation depended on coverage of all CTVs within the ITV. IMRT was given in 39 fractions to 78 Gy using the Monte-Carlo algorithm. Short-term androgen deprivation was recommended and given in 78.6% of patients. RESULTS Long-term toxicity was evaluated in 26/28 patients after a median follow-up of 7.1 years. At last follow-up, late bladder toxicity (Radiation Therapy Oncology Group, RTOG) G1 was observed in 14.3% of patients and late rectal toxicities (RTOG) of G1 (7.1%) and of G2 (3.6%) were observed. No higher graded toxicity occurred. After 7.1 years, biochemical control (biochemically no evidence of disease, bNED) was 95.5%, prostate cancer-specific survival and the distant metastasis-free survival after 7.1 years were 100% each. CONCLUSIONS CovP-based IMRT was feasible in a clinical study. Dose escalation with the CovP concept was associated by a low rate of toxicity and a high efficacy regarding local and distant control.
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Affiliation(s)
- Daniel Wegener
- Department of Radiation Oncology, University Hospital Tübingen, TübingenGermany
| | - Bernhard Berger
- Clinic for Radiation Oncology, St. Elisabethen-Clinic, Ravensburg, Germany
| | - Zhoulika Outtagarts
- Department of Radiation Oncology, University Hospital Tübingen, TübingenGermany
| | - Daniel Zips
- Department of Radiation Oncology, University Hospital Tübingen, TübingenGermany
- German Cancer Consortium (DKTK), Partner Site Tübingen; and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Frank Paulsen
- Department of Radiation Oncology, University Hospital Tübingen, TübingenGermany
| | - Martin Bleif
- Clinic for Radiology and Radiation Oncology, Alb Fils Clinic Göppingen, GöppingenGermany
| | - Daniela Thorwarth
- Section for Biomedical Physics, Department of Radiation Oncology, University Hospital Tübingen, TübingenGermany
| | - Markus Alber
- Clinic for Radiation Oncology, University Hospital Heidelberg, HeidelbergGermany
| | - Oliver Dohm
- Section for Biomedical Physics, Department of Radiation Oncology, University Hospital Tübingen, TübingenGermany
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Outaggarts Z, Wegener D, Berger B, Zips D, Paulsen F, Bleif M, Thorwarth D, Alber M, Dohm O, Müller AC. Target miss using PTV-based IMRT compared to robust optimization via coverage probability concept in prostate cancer. Acta Oncol 2020; 59:911-917. [PMID: 32436467 DOI: 10.1080/0284186x.2020.1760349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Purpose: Cure- and toxicity rates of prostate IGRT can both be affected by ill-chosen planning target volume (PTV) margins. For dose-escalated prostate radiotherapy, we studied the potential for organ at risk (OAR) sparing and compensation of prostate motion with robust plan optimization using the coverage probability (CovP) concept compared to conventional PTV-based IMRT.Material and methods: We evaluated plan quality of CovP-plans for 27 intermediate risk prostate cancer patients treated in a prospective study (78 Gy/39 fractions). Clinical target volume (CTV) and OARs were contoured on three separate CTs to capture movement and deformation. To define the internal target volume (ITV), the union of CTV1-3 was encompassed by an isotropic margin of 7 mm for the planning process. CovP-dose distribution is optimized considering weight factors for IMRT constraints derived from probabilities of systematic organ displacement in the three CTs. CovP-dose volume histograms (DVHs) were compared with additionally calculated conventional PTV-based IMRT plans. PTV-based IMRT was planned on one-single CT with an isotropically expanded CTV to generate the PTV (i.e., CTV1 + 7mm) and was evaluated on the two other CTs.Results: The CovP-concept showed higher robustness in target volume coverage. Target miss was frequently observed with PTV-based IMRT, resulting in cold spots until 70 Gy with the CovP-concept. The target dose at 74 Gy was comparable, while further the dose-escalation (75-78 Gy) was improved with PTV-based IMRT. However, dose-escalation with PTV-based IMRT was associated with increased OAR-doses, especially in high-dose areas.Conclusions: Probabilistic dose-escalated IMRT was feasible in this prospective study. Comparison of the CovP-concept with PTV-based IMRT revealed superiority with regard to target-coverage and sparing of OARs. The CovP-concept implements a robust plan optimization strategy for organ deformation and motions and could, therefore, serve as a less demanding compromise on the way to adaptive IGRT avoiding daily time-consuming re-planning. SUMMARYWe evaluated the robustness of coverage probability (CovP)-based IMRT plans within a prospective study for prostate cancer radiotherapy. The treatment plans were compared with newly calculated conventional PTV-based IMRT plans. We were able to show that CovP led to a clearly more robust target coverage by avoiding hot spots at OARs compared to conventional PTV-based IMRT. In addition, negative consequences of an inflated PTV can be ameliorated by a more relaxed CovP-based dose prescription.
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Affiliation(s)
- Zoulikha Outaggarts
- Department of Radiation Oncology, University Hospital Tübingen, Tübingen, Germany
| | - Daniel Wegener
- Department of Radiation Oncology, University Hospital Tübingen, Tübingen, Germany
| | - Bernhard Berger
- Clinic for Radiation Oncology, Oberschwaben Hospital Group, Ravensburg, Germany
| | - Daniel Zips
- Department of Radiation Oncology, University Hospital Tübingen, Tübingen, Germany
| | - Frank Paulsen
- Department of Radiation Oncology, University Hospital Tübingen, Tübingen, Germany
| | - Martin Bleif
- Clinic for Radiology and Radiation Oncology, ALB FILS Clinics Hospital on the Eichert, Goppingen, Germany
| | - Daniela Thorwarth
- Department of Radiation Oncology, Section Medical Physics, University Hospital Tübingen, Tübingen, Germany
| | - Markus Alber
- Clinic for Radiation Oncology, University Hospital Heidelberg, Heidelberg, Germany
| | - Oliver Dohm
- Department of Radiation Oncology, Section Medical Physics, University Hospital Tübingen, Tübingen, Germany
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Yock AD. Generating amorphous target margins in radiation therapy to promote maximal target coverage with minimal target size. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2018; 166:1-8. [PMID: 30415709 DOI: 10.1016/j.cmpb.2018.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/09/2018] [Accepted: 09/04/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND AND SIGNIFICANCE This work provides proof-of-principle for two versions of a heuristic approach that automatically creates amorphous radiation therapy planning target volume (PTV) margins considering local effects of tumor shape and motion to ensure adequate voxel coverage with while striving to minimize PTV size. The resulting target thereby promotes disease control while minimizing the risk of normal tissue toxicity. METHODS This work describes the mixed-PDF algorithm and the independent-PDF algorithm which generate amorphous margins around a radiation therapy target by incorporating user-defined models of target motion. Both algorithms were applied to example targets - one circular and one "cashew-shaped." Target motion was modeled by four probability density functions applied to the target quadrants. The spatially variant motion model illustrates the application of the algorithms even with tissue deformation. Performance of the margins was evaluated in silico with respect to voxelized target coverage and PTV size, and was compared to conventional techniques: a threshold-based probabilistic technique and an (an)isotropic expansion technique. To demonstrate the algorithm's clinical utility, a lung cancer patient was analyzed retrospectively. For this case, 4D CT measurements were combined with setup uncertainty to compare the PTV from the mixed-PDF algorithm with a PTV equivalent to the one used clinically. RESULTS For both targets, the mixed-PDF algorithm performed best, followed by the independent-PDF algorithm, the threshold algorithm, and lastly, the (an)isotropic algorithm. Superior coverage was always achieved by the amorphous margin algorithms for a given PTV size. Alternatively, the margin required for a particular level of coverage was always smaller (8-15%) when created with the amorphous algorithms. For the lung cancer patient, the mixed-PDF algorithm resulted in a PTV that was 13% smaller than the clinical PTV while still achieving ≥99.9% coverage. CONCLUSIONS The amorphous margin algorithms are better suited for the local effects of target shape and positional uncertainties than conventional margins. As a result, they provide superior target coverage with smaller PTVs, ensuring dose delivered to the target while decreasing the risk of normal tissue toxicity.
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Affiliation(s)
- Adam D Yock
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Cantin A, Gingras L, Lachance B, Foster W, Goudreault J, Archambault L. Dosimetric evaluation of three adaptive strategies for prostate cancer treatment including pelvic lymph nodes irradiation. Med Phys 2015; 42:7011-21. [DOI: 10.1118/1.4935529] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Analysis of inter-fraction setup errors and organ motion by daily kilovoltage cone beam computed tomography in intensity modulated radiotherapy of prostate cancer. Radiat Oncol 2012; 7:56. [PMID: 22472040 PMCID: PMC3359229 DOI: 10.1186/1748-717x-7-56] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 04/02/2012] [Indexed: 12/03/2022] Open
Abstract
Background Intensity-modulated radiotherapy (IMRT) enables a better conformality to the target while sparing the surrounding normal tissues and potentially allows to increase the dose to the target, if this is precisely and accurately determined. The goal of this work is to determine inter-fraction setup errors and prostate motion in IMRT for localized prostate cancer, guided by daily kilovoltage cone beam computed tomography (kVCBCT). Methods Systematic and random components of the shifts were retrospectively evaluated by comparing two matching modalities (automatic bone and manual soft-tissue) between each of the 641 daily kVCBCTs (18 patients) and the planning kVCT. A simulated Adaptive Radiation Therapy (ART) protocol using the average of the first 5 kVCBCTs was tested by non-parametric bootstrapping procedure. Results Shifts were < 1 mm in left-right (LR) and in supero-inferior (SI) direction. In antero-posterior (AP) direction systematic prostate motion (2.7 ± 0.7 mm) gave the major contribution to the variability of results; the averages of the absolute total shifts were significantly larger in anterior (6.3 ± 0.2 mm) than in posterior (3.9 mm ± 0.2 mm) direction. The ART protocol would reduce margins in LR, SI and anterior but not in posterior direction. Conclusions The online soft-tissue correction based on daily kVCBCT during IMRT of prostate cancer is fast and efficient. The large random movements of prostate respect to bony anatomy, especially in the AP direction, where anisotropic margins are needed, suggest that daily kVCBCT is at the present time preferable for high dose and high gradients IMRT prostate treatments.
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Zaghloul M, Mousa A, Eldebawy E, Attalla E, Shafik H, Ezzat S. Comparison of Electronic Portal Imaging and Cone Beam Computed Tomography for Position Verification in Children. Clin Oncol (R Coll Radiol) 2010; 22:850-61. [DOI: 10.1016/j.clon.2010.08.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 05/26/2010] [Accepted: 08/12/2010] [Indexed: 11/30/2022]
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Schmuecking M, Boltze C, Geyer H, Salz H, Schilling B, Wendt TG, Kloetzer KH, Marx C. Dynamic MRI and CAD vs. Choline MRS: Where is the detection level for a lesion characterisation in prostate cancer? Int J Radiat Biol 2009; 85:814-24. [DOI: 10.1080/09553000903090027] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Fu W, Yang Y, Yue NJ, Heron DE, Huq MS. A cone beam CT-guided online plan modification technique to correct interfractional anatomic changes for prostate cancer IMRT treatment. Phys Med Biol 2009; 54:1691-703. [DOI: 10.1088/0031-9155/54/6/019] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Phantom and in-vivo measurements of dose exposure by image-guided radiotherapy (IGRT): MV portal images vs. kV portal images vs. cone-beam CT. Radiother Oncol 2007; 85:418-23. [DOI: 10.1016/j.radonc.2007.10.014] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2007] [Revised: 10/08/2007] [Accepted: 10/11/2007] [Indexed: 11/15/2022]
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Li XA, Qi XS, Pitterle M, Kalakota K, Mueller K, Erickson BA, Wang D, Schultz CJ, Firat SY, Wilson JF. Interfractional Variations in Patient Setup and Anatomic Change Assessed by Daily Computed Tomography. Int J Radiat Oncol Biol Phys 2007; 68:581-91. [PMID: 17331669 DOI: 10.1016/j.ijrobp.2006.12.024] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2006] [Revised: 12/08/2006] [Accepted: 12/13/2006] [Indexed: 12/25/2022]
Abstract
PURPOSE To analyze the interfractional variations in patient setup and anatomic changes at seven anatomic sites observed in image-guided radiotherapy. METHODS AND MATERIALS A total of 152 patients treated at seven anatomic sites using a Hi-Art helical tomotherapy system were analyzed. Daily tomotherapy megavoltage computed tomography images acquired before each treatment were fused to the planning kilovoltage computed tomography images to determine the daily setup errors and organ motions and deformations. The setup errors were corrected before treatment and were used, along with the organ motions, to determine the clinical target volume/planning target volume margins. The organ motions and deformations for 3 representative patient cases (pancreas, uterus, and soft-tissue sarcoma) and for 14 kidneys of 7 patients are presented. RESULTS Interfractional setup errors in the skull, brain, and head and neck are significantly smaller than those in the chest, abdomen, pelvis, and extremities. These site-specific relationships are statistically significant. The margins required to account for these setup errors range from 3 to 8 mm for the seven sites. The margin to account for both setup errors and organ motions for kidney is 16 mm. Substantial interfractional anatomic changes were observed. For example, the pancreas moved up to +/-20 mm and volumes of the uterus and sarcoma varied <or=30% and 100%, respectively. CONCLUSION The interfractional variations in patient setup and in shapes, sizes, and positions of both targets and normal structures are site specific and may be used to determine the site-specific margins. The data presented in this work dealing with seven anatomic sites may be useful in developing adaptive radiotherapy.
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Affiliation(s)
- X Allen Li
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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Abstract
The relative doses and hot/cold spot positions around a non-radioactive gold seed, irradiated by a 6 or 18 MV photon beam in water, were calculated using Monte Carlo simulation. Phase space files of 6 and 18 MV photon beams with a field size of 1 x 1 cm2 were generated by a Varian 21 EX linear accelerator using the EGSnrc and BEAMnrc code. The seed (1.2 x 1.2 x 3.2 mm3) was positioned at the isocenter in a water phantom (20 x 20 x 20 cm2) with source-to-axis distance = 100 cm. For the single beam geometry, the relative doses (normalized to the dose at 5 mm distance above the isocenter) at the upstream seed surface were calculated to be 1.64 and 1.56 for the 6 and 18 MV beams respectively when the central beam axis (CAX) is parallel to the width of the seed. These doses were slightly higher than those (1.58 and 1.52 for 6 and 18 MV beams respectively) calculated when the CAX is perpendicular to the width of the seed. Compared to the relative dose profiles with the same beam geometry without the seed in the water phantom, the presence of the seed affects the dose distribution at about 3 mm distance beyond both the upstream and downstream seed surface. For a pair of opposing beams with equal and unequal beam weight, the hot and cold spots of both opposing beams were mixed. For a 360 degree photon arc around the longitudinal axis of the seed, the relative dose profile along the width of the seed was similar to that of the opposing beam pair, except the former geometry has a larger dose gradient near the seed surface. In this study, selected results from our simulation were compared to previous measurements using film dosimetry.
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Affiliation(s)
- James C L Chow
- Department of Radiation Oncology, University of Toronto and Radiation Medicine Program, Princess Margaret Hospital, 610 University Avenue, Toronto, ON N2G 1G3, Canada.
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Boehmer D, Maingon P, Poortmans P, Baron MH, Miralbell R, Remouchamps V, Scrase C, Bossi A, Bolla M. Guidelines for primary radiotherapy of patients with prostate cancer. Radiother Oncol 2006; 79:259-69. [PMID: 16797094 DOI: 10.1016/j.radonc.2006.05.012] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 05/15/2006] [Accepted: 05/23/2006] [Indexed: 11/21/2022]
Abstract
BACKGROUND AND PURPOSES The appropriate application of 3-D conformal radiotherapy, intensity modulated radiotherapy or image guided radiotherapy for patients undergoing radiotherapy for prostate cancer requires a standardisation of target delineation as well as clinical quality assurance procedures. PATIENTS AND METHODS Pathological and imaging studies provide valuable information on tumour extension. In addition, clinical investigations on patient positioning and immobilisation as well as treatment verification data offer an abundance of information. RESULTS Target volume definitions for different risk groups of prostate cancer patients based on pathological and imaging studies are provided. Available imaging modalities, patient positioning and treatment preparation studies as well as verification procedures are collected from literature studies. These studies are summarised and recommendations are given where appropriate. CONCLUSIONS On behalf of the European Organisation for Research and Treatment of Cancer (EORTC) Radiation Oncology Group this article presents a common set of recommendations for external beam radiotherapy of patients with prostate cancer.
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Affiliation(s)
- Dirk Boehmer
- Klinik f. Strahlentherapie, Universitätsmedizin Berlin, Charité Campus Mitte, Germany.
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Baum C, Alber M, Nüsslin F. Dosimetrische Auswirkungen der Verwendung eines Rektumhüllen-Volumens für die Bestrahlungsplanung fluenzmodulierter Strahlentherapie von Prostatakrebs. Z Med Phys 2006; 16:208-16. [PMID: 16986460 DOI: 10.1078/0939-3889-00316] [Citation(s) in RCA: 1] [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
The present study evaluated a hull-volume definition strategy for the planning organ at risk volume (PRV) for the rectum in the planning of radiotherapy of prostate cancer. The bounding volumes of rectum contours of 1 to 5 CT scans were compared on the basis of the rectum coverage probabilities for 5 patients. In addition, IMRT treatment plans were optimized using the rectum hull PRV5 of 5 CTs and each of the conventional rectum contours PRV1. The plans were compared on the basis of the organ doses caused by the individual organ motion. PRV5 allowed to cover the rectum with a probability of nearly 90% (PRV1 67%). Rectal wall dose showed a great variability for PRV1, while planned and treatment dose agreed well for PRV5 due to the improved geometric information which resulted in a better rectal sparing. In conclusion, the rectum hull-volume PRV5 is a well suited PRV for planning of IMRT dose distributions allowing dose escalation as well as rectal sparing.
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Affiliation(s)
- Christoph Baum
- Medizinische Physik, Klinik für Strahlentherapie, Schwarzwald-Baar-Klinikum, Villingen-Schwenningen.
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Baum C, Alber M, Birkner M, Nüsslin F. Robust treatment planning for intensity modulated radiotherapy of prostate cancer based on coverage probabilities. Radiother Oncol 2006; 78:27-35. [PMID: 16216359 DOI: 10.1016/j.radonc.2005.09.005] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Revised: 09/01/2005] [Accepted: 09/08/2005] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND PURPOSE To evaluate an optimization approach where coverage probabilities are incorporated into the optimization of intensity modulated radiotherapy (IMRT) to overcome the problem of margin definition in the case of overlapping planning target volume and organs at risk. PATIENTS AND METHODS IMRT plans were generated for three optimization approaches: based on a planning CT plus margin (A), on prostate and rectum contours from five pre-treatment CT plus margin (B), and on coverage probabilities (C). For approach (C), the probability of organ occupation was computed for each voxel from five pre-treatment CTs and the population distribution of systematic setup error and it was used as local weight in the costfunctions. Monte Carlo simulations of treatment courses were used to compute the probability distribution of prostate and rectal wall equivalent uniform dose (EUD). RESULTS Treatment simulations showed best and most robust results for prostate and rectal wall EUD within the population for (C). For (A) the rectal wall EUD was on average about 1.5 Gy greater than in (C), while the prostate EUD was lower than those from (C) for most of the patients for (B) (especially for those with great organ motion). CONCLUSIONS The incorporation of coverage probabilities as local weights allows for dose escalation as well as improved rectal sparing and results in a safer and more robust IMRT treatment.
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Affiliation(s)
- Christoph Baum
- Sektion für Biomedizinische Physik, Universitätsklinik für Radioonkologie, Universität Tübingen, Germany.
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