title: A treatment planning comparison of passive-scattering and intensity-modulated proton therapy for typical tumor sites.
abstract: Intensity-modulated proton therapy (IMPT) is expected to improve treatment results with fewer side effects than other proton therapies. The purpose of this study was to evaluate the tumor sites for which IMPT was effective under the same beam calculation conditions by planning IMPT for typical cases treated with passive scattering proton therapy (PSPT). We selected 16 cases of nasal cavity, lung, liver or prostate cancers as typical tumor sites receiving PSPT. The dose distributions and dose volume histograms optimized by the IMPT were compared with those optimized by the PSPT. We took particular note of the doses to the skin and organs at risk (OAR) when PSPT was replaced by IMPT. Furthermore, an improvement of the beam angles was also performed to obtain better dose distributions in the IMPT. The IMPT with the same beam angles resulted in near-maximum doses to the skin of average 78%, 64%, 84% and 99% of the PSPT doses for nasal cavity, lung, liver, and prostate cancers, respectively. However, it was difficult to improve the dose homogeneity of the target volume. The change of the IMPT beam angles could reduce the doses to OARs and skin in the case of the nasal cavity, while it had limited effect in the other cases. We concluded that IMPT was effective for reducing the doses to some OARs when treating nasal cavity, lung, liver and prostate cancers. The selection of beam angles was important in the IMPT optimization, especially for nasal cavity cancers.
authors: Proton Therapy Division, Shizuoka Cancer Center Research Institute, Nagaizumi, Shizuoka 411-8777, Japan. y.kase@scchr.jp
authors: Yuki
authors: Y
authors: Kase
authors: Haruo
authors: H
authors: Yamashita
authors: Hiroshi
authors: H
authors: Fuji
authors: Yuichi
authors: Y
authors: Yamamoto
authors: Yuehu
authors: Y
authors: Pu
authors: Chihiro
authors: C
authors: Tsukishima
authors: Shigeyuki
authors: S
authors: Murayama
mesh_terms: D003198:Computer Simulation; D005260:Female; D006801:Humans; D008954:Models, Biological; D009369:Neoplasms / Q000150:complications / Q000532:radiotherapy*; D058958:Organs at Risk / Q000528:radiation effects*; D061766:Proton Therapy; D011522:Protons / Q000009:adverse effects; D011832:Radiation Injuries / Q000209:etiology* / Q000517:prevention & control*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D012542:Scattering, Radiation; D016896:Treatment Outcome
chemical_list: D011522:Protons