Influence of Organ Motion on Conformal vs. Intensity-Modulated Pelvic Radiotherapy for Prostate Cancer

Journal Article · Fri Aug 01 04:00:00 EDT 2008 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2008.04.011· OSTI ID:21124407

Hysing, Liv Bolstad ^[1]; Skorpen, Tone Nybo ^[1]; Alber, Markus ^[2]; Fjellsbo, Lise Bauge; Helle, Svein Inge ^[1]; Muren, Ludvig Paul ^[1]

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1. Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen (Norway)
2. Section for Biomedical Physics, University Hospital for Radiation Oncology, Tuebingen (Germany)

Purpose: To compare an intensity-modulated radiotherapy (IMRT) planning approach for prostate pelvic RT with a conformal RT (CRT) approach taking into account the influence of organ-at-risk (OAR) motion. Methods and Materials: A total of 20 male patients, each with one planning computed tomography scan and five to eight treatment computed tomography scans, were used for simulation of IMRT and CRT for delivery of a prescribed dose of 50 Gy to the prostate, seminal vesicles, and pelvic lymph nodes. Planning was done in Eclipse without correcting for OAR motion. Evaluation was performed using the CRT and IMRT dose matrices and the planning and treatment OAR outlines. The generalized equivalent uniform dose (gEUD) was calculated for 894 OAR volumes using a volume-effect parameter of 4, 12, and 8 for bowel, rectum and bladder, respectively. For the bowel, the gEUD was normalized to a reference volume of 200 cm{sup 3}. For each patient and each OAR, an average of the treatment gEUDs (gEUD{sub treat}) was calculated for CRT and IMRT. The paired t test was used to compare IMRT with CRT and gEUD{sub treat} with gEUD{sub plan}. Results: The mean gEUD{sub treat} was reduced from 43 to 40 Gy, 47 to 46 Gy, and 48 to 45 Gy with IMRT for the bowel, rectum, and bladder, respectively (p < 0.001). Differences between the gEUD{sub plan} and gEUD{sub treat} were not significant (p > 0.05) for any OAR but was >6% for the bowel in 6 of 20 patients. Conclusion: Intensity-modulated RT reduced the bowel, rectum, and bladder gEUDs also under influence of OAR motion. Neither CRT nor IMRT was robust against bowel motion, but IMRT was not less robust than CRT.

• OSTI ID: 21124407
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 5 Vol. 71; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BLADDER
CARCINOMAS
COMPUTERIZED TOMOGRAPHY
LYMPH NODES
PLANNING
PROSTATE
RADIATION DOSES
RADIOTHERAPY
RECTUM