Simplified intensity-modulated arc therapy for dose escalated prostate cancer radiotherapy

Journal Article · Wed Mar 31 04:00:00 EST 2004 · Medical Dosimetry

DOI:https://doi.org/10.1016/j.meddos.2003.09.003· OSTI ID:20655470

Bauman, G; Gete, E; Chen, J Z; Wong, E

Simplified intensity-modulated arc therapy (SIMAT) employs forward planned, conformal, and avoidance arc combinations with dynamic multileaf collimation (MLC) as a simpler alternative to other forms of intensity-modulated radiotherapy (IMRT). In this work, we compare SIMAT with 4-field (4F) and 6-field (6F) 3D conformal radiation therapy (CRT) for prostate cancer treatment. Prostate, seminal vesicle, bladder, and rectum were contoured on the CT images of 10 patients being planned for radiotherapy. Two planning target volumes (PTV) were defined: PTV1 (prostate + seminal vesicles + 1.0-cm margin) and PTV2 (prostate + 1.0-cm margin). SIMAT, 4F, and 6F plans were generated with a prescription dose of 78 Gy to prostate and 54 Gy to the seminal vesicles. Differences in the 3 techniques in terms of target and rectal coverage were compared. In addition, dose distributions of the SIMAT plans were verified with measurements in a phantom. Mean dose to PTV2 (4F, 76 Gy; 6F, 78 Gy; SIMAT, 76 Gy) and the dose delivered to 95% of the target volume (D{sub 95}) were similar between the 3-techniques. Target conformity was better with SIMAT. Mean dose and calculated NTCP for the rectum were lower for SIMAT than those for 4F and 6F plans (4F 55.6 Gy vs. 6F 49.0 Gy vs. SIMAT 42.7 Gy). Mean dose to femoral heads was lower for the 4F technique vs. 6F and SIMAT techniques (4F 44.5 Gy vs. 6F 48.9 Gy vs. SIMAT 49.5 Gy). In-phantom measurement demonstrated good agreement between the plans and SIMAT treatments delivered in phantom. We concluded that SIMAT demonstrates advantages over 4F and 6F in terms of target conformity mean rectal dose and NTCP with good reproducibility in phantom. On the basis of this analysis, we have commenced a clinical pilot study of SIMAT for prostate cancer radiotherapy.

• OSTI ID: 20655470
• Journal Information: Medical Dosimetry, Journal Name: Medical Dosimetry Journal Issue: 1 Vol. 29; ISSN 0958-3947; ISSN MEDOEJ
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BLADDER
COMPUTERIZED TOMOGRAPHY
HEAD
MODULATION
NEOPLASMS
PATIENTS
PHANTOMS
PLANNING
PROSTATE
RADIATION DOSE DISTRIBUTIONS
RADIATION DOSES
RADIOTHERAPY
RECTUM