title: Validation of planning target volume margins by analyzing intrafractional localization errors for 14 prostate cancer patients based on three-dimensional cross-correlation between the prostate images of planning CT and intrafraction cone-beam CT during volumetric modulated arc therapy.
abstract: Time-averaged intreatment prostate localization errors were calculated, for the first time, by three-dimensional prostate image cross-correlation between planning CT and intrafraction kilovoltage cone-beam CT (CBCT) during volumetric modulated arc therapy (VMAT). The intrafraction CBCT volume was reconstructed by an inhouse software after acquiring cine-mode projection images during VMAT delivery. Subsequently, the margin between a clinical target volume and a planning target volume (PTV) was obtained by applying the van Herk and variant formulas using the calculated localization errors. The resulting PTV margins were approximately 2 mm in lateral direction and 4 mm in craniocaudal and anteroposterior directions, which are consistent with the margin prescription employed in our facility.
authors: Department of Radiology, University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Kenshiro
authors: K
authors: Shiraishi
authors: Department of Radiology, University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Masahiko
authors: M
authors: Futaguchi
authors: Department of Radiology, University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Akihiro
authors: A
authors: Haga
authors: Department of Radiology, University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Akira
authors: A
authors: Sakumi
authors: Department of Radiology, University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Katsutake
authors: K
authors: Sasaki
authors: Department of Radiology, University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Kentaro
authors: K
authors: Yamamoto
authors: Department of Radiology, University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Hiroshi
authors: H
authors: Igaki
authors: Department of Radiology, University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Kuni
authors: K
authors: Ohtomo
authors: Elekta KK, Tokyo 108-0023, Japan.
authors: Kiyoshi
authors: K
authors: Yoda
authors: Department of Radiology, University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors: Keiichi
authors: K
authors: Nakagawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D019583:Dose Fractionation, Radiation; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000532:radiotherapy*; D011874:Radiometry / Q000379:methods; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D047368:Tumor Burden