PURPOSE: Investigating the impact of tumor regression on the dose within cervical tumors and surrounding organs, comparing conventional, conformal, and intensity-modulated radiotherapy (IMRT) and the need for repeated treatment planning during irradiation. METHODS AND MATERIALS: Fourteen patients with cervical cancer underwent magnetic resonance (MR) imaging before treatment and once during treatment, after about 30 Gy. Target volumes and critical organs were delineated. First conventional, conformal, and IMRT plans were generated. To evaluate the impact of tumor regression, we calculated dose-volume histograms for these plans, using the delineations of the intratreatment MR images. Second conformal and IMRT plans were made based on the delineations of the intratreatment MR images. First and second plans were compared. RESULTS: The average volume receiving 95% of the prescribed dose (43 Gy) by the conventional, conformal, and IMRT plans was, respectively, for the bowel 626 cc, 427 cc, and 232 cc; for the rectum 101 cc, 90 cc, and 60 cc; and for the bladder 89 cc, 70 cc, and 58 cc. The volumes of critical organs at this dose level were significantly reduced using IMRT compared with conventional and conformal planning (p < 0.02 in all cases). After having delivered about 30 Gy external beam radiation therapy, the primary gross tumor volumes decreased on average by 46% (range, 6.1-100%). The target volumes on the intratreatment MR images remained sufficiently covered by the 95% isodose. Second IMRT plans significantly diminished the treated bowel volume, if the primary gross tumor volumes decreased >30 cc. CONCLUSIONS: Intensity-modulated radiation therapy is superior in sparing of critical organs compared with conventional and conformal treatment, with adequate coverage of the target volumes. Intensity-modulated radiation therapy remains superior after 30 Gy external beam radiation therapy, despite tumor regression and internal organ motion. Repeated IMRT planning can improve the sparing of the bowel and rectum in patients with substantial tumor regression.
PURPOSE: Investigating the impact of tumor regression on the dose within cervical tumors and surrounding organs, comparing conventional, conformal, and intensity-modulated radiotherapy (IMRT) and the need for repeated treatment planning during irradiation. METHODS AND MATERIALS: Fourteen patients with cervical cancer underwent magnetic resonance (MR) imaging before treatment and once during treatment, after about 30 Gy. Target volumes and critical organs were delineated. First conventional, conformal, and IMRT plans were generated. To evaluate the impact of tumor regression, we calculated dose-volume histograms for these plans, using the delineations of the intratreatment MR images. Second conformal and IMRT plans were made based on the delineations of the intratreatment MR images. First and second plans were compared. RESULTS: The average volume receiving 95% of the prescribed dose (43 Gy) by the conventional, conformal, and IMRT plans was, respectively, for the bowel 626 cc, 427 cc, and 232 cc; for the rectum 101 cc, 90 cc, and 60 cc; and for the bladder 89 cc, 70 cc, and 58 cc. The volumes of critical organs at this dose level were significantly reduced using IMRT compared with conventional and conformal planning (p < 0.02 in all cases). After having delivered about 30 Gy external beam radiation therapy, the primary gross tumor volumes decreased on average by 46% (range, 6.1-100%). The target volumes on the intratreatment MR images remained sufficiently covered by the 95% isodose. Second IMRT plans significantly diminished the treated bowel volume, if the primary gross tumor volumes decreased >30 cc. CONCLUSIONS: Intensity-modulated radiation therapy is superior in sparing of critical organs compared with conventional and conformal treatment, with adequate coverage of the target volumes. Intensity-modulated radiation therapy remains superior after 30 Gy external beam radiation therapy, despite tumor regression and internal organ motion. Repeated IMRT planning can improve the sparing of the bowel and rectum in patients with substantial tumor regression.
Authors: Wang Jianyang; Tian Yuan; Tang Yuan; Wang Xin; Li Ning; Ren Hua; Fang Hui; Feng Yanru; Wang Shulian; Song Yongwen; Liu Yueping; Wang Weihu; Li Yexiong; Jin Jing Journal: Radiol Med Date: 2015-11-27 Impact factor: 3.469
Authors: Sarah A Mason; Ingrid M White; Susan Lalondrelle; Jeffrey C Bamber; Emma J Harris Journal: Ultrasound Med Biol Date: 2020-01-08 Impact factor: 2.998
Authors: Karen Lim; Beth Erickson; Ina M Jürgenliemk-Schulz; David Gaffney; Carien L Creutzberg; Akila Viswanathan; Lorraine Portelance; Sushil Beriwal; Aaron Wolfson; Walter Bosch; Jennifer De Los Santos; Catheryn Yashar; Anuja Jhingran; Mahesh Varia; Issam El Naqa; Bronwyn King; Anthony Fyles Journal: Pract Radiat Oncol Date: 2015-07-02
Authors: Chao Lu; Sudhakar Chelikani; Xenophon Papademetris; Jonathan P Knisely; Michael F Milosevic; Zhe Chen; David A Jaffray; Lawrence H Staib; James S Duncan Journal: Med Image Anal Date: 2011-05-20 Impact factor: 8.545
Authors: Johannes C A Dimopoulos; Gertrude Schirl; Anja Baldinger; Thomas H Helbich; Richard Pötter Journal: Strahlenther Onkol Date: 2009-05-15 Impact factor: 3.621