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White I, McQuaid D, McNair H, Dunlop A, Court S, Hopkins N, Thomas K, Dearnaley D, Bhide S, Lalondrelle S. Geometric and dosimetric evaluation of the differences between rigid and deformable registration to assess interfraction motion during pelvic radiotherapy. Phys Imaging Radiat Oncol 2019; 9:97-102. [PMID: 33458433 PMCID: PMC7807633 DOI: 10.1016/j.phro.2019.02.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND AND PURPOSE Appropriate internal margins are essential to avoid a geographical miss in intensity-modulated radiation therapy (IMRT) for endometrial cancer (EC). This study evaluated interfraction target motion using rigid and non-rigid approximation strategies and calculated internal margins based on random and systematic errors using traditional rigid margin recipes. Dosimetric impact of target motion was also investigated. MATERIALS AND METHODS Cone beam CTs (CBCTs) were acquired days 1-4 and then weekly in 17 patients receiving adjuvant IMRT for EC; a total of 169 CBCTs were analysed. Interfraction motion for the clinical target volume vaginal vault and upper vagina (CTVv) was measured using bony landmarks and deformation vector field displacement (DVFD) within a 1 mm internal wall of CTVv. Patient and population systematic and random errors were estimated and margins calculated. Delivered dose to the CTVv and organs at risk was estimated. RESULTS There was a significant difference in target motion assessment using the different registration strategies (p < 0.05). DVFD up to 30 mm occurred in the anterior/posterior direction, which was not accounted for in PTV margins using rigid margin recipes. Underdosing of CTVv D95% occurred in three patients who had substantial reductions in rectal volume (RV) during treatment. RV relative to the planning CT was moderately correlated with anterior/posterior displacement (r = 0.6) and mean relative RV during treatment was strongly correlated with mean relative RV at CBCT acquired days 1-3 (r = 0.8). CONCLUSION Complex and extensive geometric changes occur to the CTVv, which are not accounted for in margin recipes using rigid approximation. Contemporary margin recipes and adaptive treatment planning based on non-rigid approximation are recommended.
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Key Words
- CBCT, cone beam CT
- CTVv, clinical target volume vaginal vault and upper vagina
- DIR, deformable image registration
- DSC, dice similarity coefficient
- DVFD, deformation vector field displacement
- EBRT, external beam radiotherapy
- EC, endometrial cancer
- IMRT, intensity modulated radiotherapy
- MDA, mean distance to agreement
- OARs, organs at risk
- RV, rectal volume
- pCT, planning CT
- Σ, systematic
- σ, random
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Affiliation(s)
- Ingrid White
- Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, Surrey, United Kingdom
| | - Dualta McQuaid
- Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, Surrey, United Kingdom
| | - Helen McNair
- Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, Surrey, United Kingdom
| | - Alex Dunlop
- Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, Surrey, United Kingdom
| | - Steven Court
- Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, Surrey, United Kingdom
| | - Naomi Hopkins
- Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, Surrey, United Kingdom
| | - Karen Thomas
- Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, Surrey, United Kingdom
| | - David Dearnaley
- Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, Surrey, United Kingdom
| | - Shree Bhide
- Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, Surrey, United Kingdom
| | - Susan Lalondrelle
- Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, Surrey, United Kingdom
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Dosimetric comparison between three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) in the treatment of different stages of nasopharyngeal carcinoma. JOURNAL OF RADIOTHERAPY IN PRACTICE 2018. [DOI: 10.1017/s1460396918000377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractBackgroundThis work aims to compare the dosimetric performance of three-dimensional conformal radiotherapy (3D-CRT), a relatively available technique in developing countries, to intensity-modulated radiotherapy (IMRT) in the treatment of different stages of nasopharyngeal carcinoma (NPC).Materials and MethodsAccording to the diagnostic stages, 40 NPC patients were divided into two equal groups. Three planning techniques such as 3D-CRT, seven-field IMRT (7F-IMRT) and nine-field IMRT (9F-IMRT) were compared. Dose prescriptions of 70 and 66 Gy were delivered in 35 fractions to gross planning target volume (PTV1) and bilateral retropharyngeal carcinoma (PTV2), respectively.ResultsStage I dose data for almost all of the three investigated planning techniques obey the international recommendations. The dose delivered to PTV1 and PTV2 for 3D-CRT and 7F-IMRT are statistically similar, whereas 9F-IMRT is significantly better than 3D-CRT. For organs at risk (OARs), the delivered dose is significantly better for 9F-IMRT compared with the other two techniques, whereas 7F-IMRT is significantly better than 3D-CRT.Conclusions3D-CRT is an acceptable alternative treatment technique for stage I NPC patients in developing countries suffering from the lack of advanced radiotherapy treatment techniques. 3D-CRT and 7F-IMRT have comparable performance in PTVs, while 9F-IMRT is superior in PTVs and OARs.
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Zaorsky NG, Showalter TN, Ezzell GA, Nguyen PL, Assimos DG, D'Amico AV, Gottschalk AR, Gustafson GS, Keole SR, Liauw SL, Lloyd S, McLaughlin PW, Movsas B, Prestidge BR, Taira AV, Vapiwala N, Davis BJ. ACR Appropriateness Criteria for external beam radiation therapy treatment planning for clinically localized prostate cancer, part II of II. Adv Radiat Oncol 2017; 2:437-454. [PMID: 29114613 PMCID: PMC5605284 DOI: 10.1016/j.adro.2017.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/10/2017] [Indexed: 12/21/2022] Open
Abstract
PURPOSE To present the most updated American College of Radiology (ACR) Appropriateness Criteria formed by an expert panel on the appropriate delivery of external beam radiation to manage stage T1 and T2 prostate cancer (in the definitive setting and post-prostatectomy) and to provide clinical variants with expert recommendations based on accompanying Appropriateness Criteria for target volumes and treatment planning. METHODS AND MATERIALS The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a panel of multidisciplinary experts. The guideline development and revision process includes an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In instances in which evidence is lacking or equivocal, expert opinion may supplement available evidence to recommend imaging or treatment. RESULTS The panel summarizes the most recent and relevant literature on the topic, including organ motion and localization methods, image guidance, and delivery techniques (eg, 3-dimensional conformal intensity modulation). The panel presents 7 clinical variants, including (1) a standard case and cases with (2) a distended rectum, (3) a large-volume prostate, (4) bilateral hip implants, (5) inflammatory bowel disease, (6) prior prostatectomy, and (7) a pannus extending into the radiation field. Each case outlines the appropriate techniques for simulation, treatment planning, image guidance, dose, and fractionation. Numerical rating and commentary is given for each treatment approach in each variant. CONCLUSIONS External beam radiation is a key component of the curative management of T1 and T2 prostate cancer. By combining the most recent medical literature, these Appropriateness Criteria can aid clinicians in determining the appropriate treatment delivery and personalized approaches for individual patients.
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Affiliation(s)
| | | | - Gary A. Ezzell
- Mayo Clinic, Phoenix, Arizona (research author [contributing])
| | - Paul L. Nguyen
- Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, Massachusetts (panel vice-chair)
| | - Dean G. Assimos
- University of Alabama School of Medicine, Birmingham, Alabama (American Urological Association)
| | - Anthony V. D'Amico
- Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, Massachusetts (American Society of Clinical Oncology)
| | | | | | | | | | - Shane Lloyd
- Huntsman Cancer Hospital, Salt Lake City, Utah
| | | | | | | | - Al V. Taira
- Mills Peninsula Hospital, San Mateo, California
| | - Neha Vapiwala
- University of Pennsylvania, Philadelphia, Pennsylvania
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Zaorsky NG, Showalter TN, Ezzell GA, Nguyen PL, Assimos DG, D'Amico AV, Gottschalk AR, Gustafson GS, Keole SR, Liauw SL, Lloyd S, McLaughlin PW, Movsas B, Prestidge BR, Taira AV, Vapiwala N, Davis BJ. ACR Appropriateness Criteria ® external beam radiation therapy treatment planning for clinically localized prostate cancer, part I of II. Adv Radiat Oncol 2016; 2:62-84. [PMID: 28740916 PMCID: PMC5514238 DOI: 10.1016/j.adro.2016.10.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/12/2016] [Indexed: 12/24/2022] Open
Affiliation(s)
| | | | | | - Gary A Ezzell
- Mayo Clinic, Phoenix, Arizona (research author, contributing)
| | - Paul L Nguyen
- Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, Massachusetts (panel vice-chair)
| | - Dean G Assimos
- University of Alabama School of Medicine, Birmingham, Alabama (American Urological Association)
| | - Anthony V D'Amico
- Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, Massachusetts (American Society of Clinical Oncology)
| | | | | | | | | | - Shane Lloyd
- Huntsman Cancer Hospital, Salt Lake City, Utah
| | | | | | | | - Al V Taira
- Mills Peninsula Hospital, San Mateo, California
| | - Neha Vapiwala
- University of Pennsylvania, Philadelphia, Pennsylvania
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Tomita T, Nakamura M, Hirose Y, Kitsuda K, Notogawa T, Miki K, Nakamura K, Ishigaki T. Multivariate analysis of factors predicting prostate dose in intensity-modulated radiotherapy. Med Dosim 2014; 39:360-5. [PMID: 25155214 DOI: 10.1016/j.meddos.2014.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 06/12/2014] [Indexed: 10/24/2022]
Abstract
We conducted a multivariate analysis to determine relationships between prostate radiation dose and the state of surrounding organs, including organ volumes and the internal angle of the levator ani muscle (LAM), based on cone-beam computed tomography (CBCT) images after bone matching. We analyzed 270 CBCT data sets from 30 consecutive patients receiving intensity-modulated radiation therapy for prostate cancer. With patients in the supine position on a couch with the HipFix system, data for center of mass (COM) displacement of the prostate and the state of individual organs were acquired and compared between planning CT and CBCT scans. Dose distributions were then recalculated based on CBCT images. The relative effects of factors on the variance in COM, dose covering 95% of the prostate volume (D95%), and percentage of prostate volume covered by the 100% isodose line (V100%) were evaluated by a backward stepwise multiple regression analysis. COM displacement in the anterior-posterior direction (COMAP) correlated significantly with the rectum volume (δVr) and the internal LAM angle (δθ; R = 0.63). Weak correlations were seen for COM in the left-right (R = 0.18) and superior-inferior directions (R = 0.31). Strong correlations between COMAP and prostate D95% and V100% were observed (R ≥ 0.69). Additionally, the change ratios in δVr and δθ remained as predictors of prostate D95% and V100%. This study shows statistically that maintaining the same rectum volume and LAM state for both the planning CT simulation and treatment is important to ensure the correct prostate dose in the supine position with bone matching.
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Affiliation(s)
| | - Mitsuhiro Nakamura
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
| | | | - Kenji Kitsuda
- Division of Radiology, Osaka Red Cross Hospital, Osaka, Japan
| | - Takuya Notogawa
- Division of Radiology, Osaka Red Cross Hospital, Osaka, Japan
| | - Katsuhito Miki
- Division of Radiology, Osaka Red Cross Hospital, Osaka, Japan
| | - Kiyonao Nakamura
- Department of Radiation Oncology, Osaka Red Cross Hospital, Osaka, Japan
| | - Takashi Ishigaki
- Department of Radiation Oncology, Osaka Red Cross Hospital, Osaka, Japan
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Onishi H, Kuriyama K, Komiyama T, Marino K, Araya M, Saito R, Aoki S, Maehata Y, Tominaga L, Sano N, Oguri M, Onohara K, Watanabe I, Koshiishi T, Ogawa K, Araki T. Large prostate motion produced by anal contraction. Radiother Oncol 2012; 104:390-4. [DOI: 10.1016/j.radonc.2012.04.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 12/04/2011] [Accepted: 04/29/2012] [Indexed: 11/26/2022]
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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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Falco MD, D'Andrea M, Fedele D, Barbarino R, Benassi M, Giudice E, Hamoud E, Ingrosso G, Ladogana P, Santarelli F, Tortorelli G, Santoni R. Preliminary experience of a predictive model to define rectal volume and rectal dose during the treatment of prostate cancer. Br J Radiol 2011; 84:819-25. [PMID: 21849366 DOI: 10.1259/bjr/25741415] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES The aim of this study was to define a method to evaluate the total dose delivered to the rectum during the whole treatment course in six patients undergoing irradiation for prostate cancer using an offline definition of organ motion with images from a cone beam CT (CBCT) scanner available on a commercial linear accelerator. METHODS Patient set-up was verified using a volumetric three-dimensional CBCT scanner; 9-14 CBCT scans were obtained for each patient. Images were transferred to a commercial treatment planning system for offline organ motion analysis. The shape of the rectums were used to obtain a mean dose-volume histogram (<DVH>), which was the average of the DVHs of the rectums as they appeared in each verification CBCT. A geometric model of an average rectum (AR) was produced using the rectal contours delineated on the CBCT scans (DVH(AR)). To check whether the first week of treatment was representative of the whole treatment course, we evaluated the DVHs related to only the first five CBCT scans (<DVH5> and DVH(AR5)). Finally, the influence of a dietary protocol on the goodness of our results was considered. RESULTS In all six patients the original rectal DVH for the planning CT scan showed higher values than all DVHs. CONCLUSION Although the application of the model to a larger set of patients is necessary to confirm this trend, reconstruction of a representative volume of the rectum throughout the entire treatment course seems feasible.
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Affiliation(s)
- M D Falco
- Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata University General Hospital, Rome, Italy.
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Sterzing F, Engenhart-Cabillic R, Flentje M, Debus J. Image-guided radiotherapy: a new dimension in radiation oncology. DEUTSCHES ARZTEBLATT INTERNATIONAL 2011; 108:274-80. [PMID: 21603562 DOI: 10.3238/arztebl.2011.0274] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 05/17/2010] [Indexed: 12/21/2022]
Abstract
BACKGROUND The vital importance of imaging techniques in radiation oncology now extends beyond diagnostic evaluation and treatment planning. Recent technical advances have enabled the integration of various imaging modalities into the everyday practice of radiotherapy directly at the linear accelerator, improving the management of inter- and intrafractional variations. METHODS We present the topic of image-guided radiotherapy (IGRT) on the basis of a selective review of the literature. RESULTS IGRT can be performed with the aid of ultrasound, 2D X-ray devices, and computed tomography. It enables instant correction for positioning deviations and thereby improves the precision of daily radiotherapy fractions. It also enables immediate adjustment for changes in the position and filling status of the internal organs. Anatomical changes that take place over the course of radiotherapy, such as weight loss, tumor shrinkage, and the opening of atelectases, can be detected as they occur and accounted for in dosimetric calculations. There have not yet been any randomized controlled trials showing that IGRT causes fewer adverse effects or improves tumor control compared to conventional radiotherapy. CONCLUSION IGRT is more precise and thus potentially safer than conventional radiotherapy. It also enables the application of special radiotherapeutic techniques with narrow safety margins in the vicinity of radiosensitive organs. Proper patient selection for IGRT must take account of the goals of treatment and the planning characteristics, as well as the available technical and human resources. IGRT should be used for steep dose gradients near organs at risk, for highly conformal dose distributions in the gastrointestinal tract where adjustment for filling variations is needed, for high-precision dose escalation to avoid geographic miss, and for patients who cannot lie perfectly still because of pain or claustrophobia.
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Affiliation(s)
- Florian Sterzing
- Abteilung für Radio onkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Germany.
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Bratengeier K, Polat B, Gainey M, Grewenig P, Meyer J, Flentje M. Is ad-hoc plan adaptation based on 2-Step IMRT feasible? Radiother Oncol 2009; 93:266-72. [DOI: 10.1016/j.radonc.2009.08.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 07/16/2009] [Accepted: 08/07/2009] [Indexed: 10/20/2022]
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Fiducial-based quantification of prostate tilt using cone beam computer tomography (CBCT). Radiother Oncol 2007; 85:247-50. [DOI: 10.1016/j.radonc.2007.09.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Revised: 09/06/2007] [Accepted: 09/06/2007] [Indexed: 11/19/2022]
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Bratengeier K, Guckenberger M, Meyer J, Müller G, Pfreundner L, Schwab F, Flentje M. A comparison between 2-Step IMRT and conventional IMRT planning. Radiother Oncol 2007; 84:298-306. [PMID: 17707937 DOI: 10.1016/j.radonc.2007.06.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 06/20/2007] [Accepted: 06/28/2007] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND PURPOSE 2-Step intensity modulated radiation therapy (2-Step IMRT) is an IMRT segmentation procedure based on analytical approximations [Bratengeier K. 2-Step IMAT and 2-Step IMRT: a geometrical approach. Med Phys 2005;32:777-785; Bratengeier K. 2-Step IMAT and 2-Step IMRT in three dimensions. Med Phys 2005;32:3849-3861]. The aim was to benchmark it with other IMRT algorithms and to establish it as planning tool for fast IMRT application with a reduced number of segments. MATERIALS AND METHODS 2-Step IMRT plans were compared with IMRT-solutions obtained with methods from a commercial planning system (Pinnacletrade mark TPS). The four clinical cases chosen were: paraspinal tumour, carcinoma of the prostate, head and neck carcinoma and breast carcinoma. In addition the "Quasimodo" phantom study was used to compare the quality of the 2-Step IMRT method with respect to other planning procedures in the ESTRO study. RESULTS The number of segments (and - to a minor degree - the monitor units per dose) of the majority of 2-Step IMRT plans was lower than for the commercial algorithms. The quality of the 2-Step IMRT-plan was comparable. In the Quasimodo comparison 2-Step IMRT plans with nine beams would place in the mid-range of all participants, whereas the 15-beam arrangements could compete with the best results. CONCLUSIONS 2-Step IMRT is a valuable IMRT segmentation method, especially if the number of segments is to be limited (e.g. for reasons of precision, speed and leakage radiation).
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Affiliation(s)
- Klaus Bratengeier
- Universität Würzburg, Klinik und Poliklinik für Strahlentherapie, Würzburg, Germany.
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Pinkawa M, Siluschek J, Gagel B, Demirel C, Asadpour B, Holy R, Eble MJ. Influence of the initial rectal distension on posterior margins in primary and postoperative radiotherapy for prostate cancer. Radiother Oncol 2006; 81:284-90. [PMID: 17125866 DOI: 10.1016/j.radonc.2006.10.028] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 09/11/2006] [Accepted: 10/25/2006] [Indexed: 11/24/2022]
Abstract
BACKGROUND AND PURPOSE The aim of the study was to define the effect of different rectum fillings in the planning CT study on the posterior clinical target volume (CTV) displacements (PD) in primary and postoperative radiotherapy (RT) for prostate cancer. MATERIALS AND METHODS Fifty patients underwent CT scans in supine position with a full bladder and an empty bladder before RT and at several points in time during the treatment. PD were determined depending on the initial rectum volume (RV), average cross-sectional rectal area (CSA), and the rectal diameter at the level of the bladder neck (RD). RESULTS Posterior CTV motion was not found to be minimal with a particularly small initial rectum filling. Steeply increasing PD resulted for patients with RV>120cm(3), CSA>12cm(2), and RD>4.5cm. While below these critical values a posterior margin of 6mm/9mm allowed to cover 80%/90% of displacements, 18mm/24mm were needed for patients with larger rectum fillings. No correlation of increasing rectum distension with increasing PD was found at the apex level. PD could not be reduced by voiding the bladder. CONCLUSIONS Defining the posterior margin in prostate RT, the initial rectum distension and the superior-inferior CTV level has to be considered. Patients with large initial rectum fillings have preferentially the need for repeated planning CT scans or image-guided RT.
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Affiliation(s)
- Michael Pinkawa
- Department of Radiation Oncology, RWTH Aachen University, Aachen, Germany.
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Guckenberger M, Meyer J, Baier K, Vordermark D, Flentje M. Distinct effects of rectum delineation methods in 3D-conformal vs. IMRT treatment planning of prostate cancer. Radiat Oncol 2006; 1:34. [PMID: 16956403 PMCID: PMC1570470 DOI: 10.1186/1748-717x-1-34] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Accepted: 09/06/2006] [Indexed: 11/19/2022] Open
Abstract
Background The dose distribution to the rectum, delineated as solid organ, rectal wall and rectal surface, in 3D conformal (3D-CRT) and intensity-modulated radiotherapy treatment (IMRT) planning for localized prostate cancer was evaluated. Materials and methods In a retrospective planning study 3-field, 4-field and IMRT treatment plans were analyzed for ten patients with localized prostate cancer. The dose to the rectum was evaluated based on dose-volume histograms of 1) the entire rectal volume (DVH) 2) manually delineated rectal wall (DWH) 3) rectal wall with 3 mm wall thickness (DWH3) 4) and the rectal surface (DSH). The influence of the rectal filling and of the seminal vesicles' anatomy on these dose parameters was investigated. A literature review of the dose-volume relationship for late rectal toxicity was conducted. Results In 3D-CRT (3-field and 4-field) the dose parameters differed most in the mid-dose region: the DWH showed significantly lower doses to the rectum (8.7% ± 4.2%) compared to the DWH3 and the DSH. In IMRT the differences between dose parameters were larger in comparison with 3D-CRT. Differences were statistically significant between DVH and all other dose parameters and between DWH and DSH. Mean doses were increased by 23.6% ± 8.7% in the DSH compared to the DVH in the mid-dose region. Furthermore, both the rectal filling and the anatomy of the seminal vesicles influenced the relationship between the dose parameters: a significant correlation of the difference between DVH and DWH and the rectal volume was seen in IMRT treatment. Discussion The method of delineating the rectum significantly influenced the dose representation in the dose-volume histogram. This effect was pronounced in IMRT treatment planning compared to 3D-CRT. For integration of dose-volume parameters from the literature into clinical practice these results have to be considered.
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Affiliation(s)
- Matthias Guckenberger
- Department of Radiation Oncology, University of Wuerzburg, Josef-Schneider-Str. 11, 97080 Wuerzburg, Germany
| | - Jürgen Meyer
- Department of Radiation Oncology, University of Wuerzburg, Josef-Schneider-Str. 11, 97080 Wuerzburg, Germany
| | - Kurt Baier
- Department of Radiation Oncology, University of Wuerzburg, Josef-Schneider-Str. 11, 97080 Wuerzburg, Germany
| | - Dirk Vordermark
- Department of Radiation Oncology, University of Wuerzburg, Josef-Schneider-Str. 11, 97080 Wuerzburg, Germany
| | - Michael Flentje
- Department of Radiation Oncology, University of Wuerzburg, Josef-Schneider-Str. 11, 97080 Wuerzburg, Germany
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