title: Whole-pelvic radiotherapy with spot-scanning proton beams for uterine cervical cancer: a planning study.
abstract: The aim of this study was to compare the dosimetric parameters of whole-pelvic radiotherapy (WPRT) for cervical cancer among plans involving 3D conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), or spot-scanning proton therapy (SSPT). The dose distributions of 3D-CRT-, IMRT-, and SSPT-based WPRT plans were compared in 10 patients with cervical cancer. All of the patients were treated with a prescribed dose of 50.4 Gy in 1.8-Gy daily fractions, and all of the plans involved the same planning target volume (PTV) constrictions. A 3D-CRT plan involving a four-field box, an IMRT plan involving seven coplanar fields, and an SSPT plan involving four fields were created. The median PTV D95% did not differ between the 3D-CRT, IMRT and SSPT plans. The median conformity index 95% and homogeneity index of the IMRT and SSPT were better than those of the 3D-CRT. The homogeneity index of the SSPT was better than that of the IMRT. SSPT resulted in lower median V20 values for the bladder wall, small intestine, colon, bilateral femoral heads, skin, and pelvic bone than IMRT. Comparing the Dmean values, SSPT spared the small intestine, colon, bilateral femoral heads, skin and pelvic bone to a greater extent than the other modalities. SSPT can reduce the irradiated volume of the organs at risk compared with 3D-CRT and IMRT, while maintaining excellent PTV coverage. Further investigations of SSPT are warranted to assess its role in the treatment of cervical cancer.
authors.affiliation: Department of Radiation Oncology, Nagoya Proton Therapy Center, 1-1-1 Hirate-cho, Kita-ku, Nagoya 462-8508, Japan Department of Radiation Oncology, Nagoya City West Medical Center, 1-1-1 Hirate-cho, Kita-ku, Nagoya 462-8508, Japan Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan hashimoto.ncu@gmail.com.
authors.forename: Shingo
authors.initials: S
authors.lastname: Hashimoto
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Shibamoto
authors.affiliation: Department of Radiation Oncology, Nagoya Proton Therapy Center, 1-1-1 Hirate-cho, Kita-ku, Nagoya 462-8508, Japan.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Iwata
authors.affiliation: Department of Radiation Oncology, Nagoya Proton Therapy Center, 1-1-1 Hirate-cho, Kita-ku, Nagoya 462-8508, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ogino
authors.affiliation: Department of Proton Therapy Technology, Nagoya Proton Therapy Center, 1-1-1 Hirate-cho, Kita-ku, Nagoya 462-8508, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shibata
authors.affiliation: Department of Proton Therapy Physics, Nagoya Proton Therapy Center, 1-1-1 Hirate-cho, Kita-ku, Nagoya 462-8508, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Toshito
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
authors.forename: Chikao
authors.initials: C
authors.lastname: Sugie
authors.affiliation: Department of Radiation Oncology, Nagoya Proton Therapy Center, 1-1-1 Hirate-cho, Kita-ku, Nagoya 462-8508, Japan.
authors.forename: Jun-Etsu
authors.initials: JE
authors.lastname: Mizoe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008875:Middle Aged; D010388:Pelvis / Q000528:radiation effects*; D011522:Protons; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal; D050397:Radiotherapy, Intensity-Modulated; D015203:Reproducibility of Results; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy*
chemical_list: D011522:Protons
keywords: 3D-CRT; IMRT; cervical cancer; dosimetry; spot scanning proton therapy; whole-pelvic radiotherapy