title: Dose-volume histogram comparison between static 5-field IMRT with 18-MV X-rays and helical tomotherapy with 6-MV X-rays.
abstract: We treated prostate cancer patients with static 5-field intensity-modulated radiation therapy (IMRT) using linac 18-MV X-rays or tomotherapy with 6-MV X-rays. As X-ray energies differ, we hypothesized that 18-MV photon IMRT may be better for large patients and tomotherapy may be more suitable for small patients. Thus, we compared dose-volume parameters for the planning target volume (PTV) and organs at risk (OARs) in 59 patients with T1-3 N0M0 prostate cancer who had been treated using 5-field IMRT. For these same patients, tomotherapy plans were also prepared for comparison. In addition, plans of 18 patients who were actually treated with tomotherapy were analyzed. The evaluated parameters were homogeneity indicies and a conformity index for the PTVs, and D2 (dose received by 2% of the PTV in Gy), D98, Dmean and V10-70 Gy (%) for OARs. To evaluate differences by body size, patients with a known body mass index were grouped by that index ( <21; 21-25; and >25 kg/m(2)). For the PTV, all parameters were higher in the tomotherapy plans compared with the 5-field IMRT plans. For the rectum, V10 Gy and V60 Gy were higher, whereas V20 Gy and V30 Gy were lower in the tomotherapy plans. For the bladder, all parameters were higher in the tomotherapy plans. However, both plans were considered clinically acceptable. Similar trends were observed in 18 patients treated with tomotherapy. Obvious trends were not observed for body size. Tomotherapy provides equivalent dose distributions for PTVs and OARs compared with 18-MV 5-field IMRT. Tomotherapy could be used as a substitute for high-energy photon IMRT for prostate cancer regardless of body size.
authors.affiliation: Department of Radiology, Nagoya City University Graduate school of Medical Science, Nagoya 467-8601, Japan Department of Radiology, Okazaki City Hospital, 3-1 Aza-Goshoai, Koryuzi-cho, Okazaki, Aichi 444-8553, Japan hakihiro@gmail.com.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hayashi
authors.affiliation: Department of Radiology, Nagoya City University Graduate school of Medical Science, Nagoya 467-8601, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Shibamoto
authors.affiliation: Department of Radiology, Nagoya City University Graduate school of Medical Science, Nagoya 467-8601, Japan Department of Radiation Oncology, Nagoya Proton Therapy Center, Nagoya City West Medical Center, 1-1-1 Hirate-cho, Kita-ku, Nagoya, Aichi 462-8508, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Hattori
authors.affiliation: Yokohama Cyberknife Center, Yokohama, Kanagawa 241-0014, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tamura
authors.affiliation: Department of Radiology, Nagoya City University Graduate school of Medical Science, Nagoya 467-8601, Japan Yokohama Cyberknife Center, Yokohama, Kanagawa 241-0014, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Iwabuchi
authors.affiliation: Department of Radiology, Okazaki City Hospital, 3-1 Aza-Goshoai, Koryuzi-cho, Okazaki, Aichi 444-8553, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Otsuka
authors.affiliation: Department of Radiology, Nagoya City University Graduate school of Medical Science, Nagoya 467-8601, Japan.
authors.forename: Chikao
authors.initials: C
authors.lastname: Sugie
authors.affiliation: Department of Radiology, Nagoya City University Graduate school of Medical Science, Nagoya 467-8601, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yanagi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003627:Data Interpretation, Statistical; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects*; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D047368:Tumor Burden; D014965:X-Rays
keywords: IMRT; body size; dose–volume histogram; helical tomotherapy; prostate cancer