title: [Influence of high-definition multileaf collimator for three-dimensional conformal radiotherapy and intensity-modulated radiotherapy of prostate cancer].
abstract: The focus of this work is to evaluate the dosimetric impact of treatment planning for three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) of prostate cancer using Varian/BrainLAB 120-leaf high-definition multileaf collimator (HD120 MLC) with 2.5 mm leaf width and Varian 120-leaf millennium multileaf collimator (M120 MLC) with 5 mm leaf width. We measured the leaf transmission and dosimetric leaf gap (DLG) of two multileaf collimator (MLC) systems using Farmer ionization chamber. The dosimetric impact of treatment planning for 3DCRT and IMRT of prostate cancer for ten clinical cases using two MLC systems was evaluated quantitatively. 3DCRT was divided to 3DCRT(middle) as fitting at middle of leaf tip and 3DCRT(outside) as fitting at outside of leaf tip. The leaf transmission factor and DLG of HD120 MLC for 6 and 10 MV X-ray decreased by 0.2% and 1 mm, respectively, compared to M120 MLC. The mean conformity index of PTV of treatment planning for prostate 3DCRT(middle), 3DCRT(outside) , and IMRT decreased by 0.9%, 6.6%, and 0.9% and the mean homogeneity index increased 2.3%, 13.0%, and 4.2%, respectively. The mean V20, V40, and V65 decreased by 2.4%, 6.6%, and 4.5% for bladder and 3.3%, 6.1%, and 5.9% for rectum, respectively. The results of this work demonstrated that the dose conformity of PTV improved and the dose of bladder and rectum decreased for 3DCRT and IMRT of prostate cancer using HD120 MLC compared to M120 MLC, because of reduction of leaf width, leaf transmission, and rounded leaf end transmission.
authors: State of the Art Treatment Center, Hiroshima Heiwa Clinic.
authors: Sachie
authors: S
authors: Fujimoto
authors: Kaoru
authors: K
authors: Ono
authors: Kengo
authors: K
authors: Furukawa
authors: Tsuyoshi
authors: T
authors: Kudo
authors: Yukio
authors: Y
authors: Akagi
authors: Tadashi
authors: T
authors: Koyama
authors: Yutaka
authors: Y
authors: Hirokawa
authors: Shintarou
authors: S
authors: Kawai
authors: Takeo
authors: T
authors: Nakashima
mesh_terms: D004867:Equipment Design; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation*; D020266:Radiotherapy, Conformal / Q000295:instrumentation*; D050397:Radiotherapy, Intensity-Modulated / Q000295:instrumentation*