title: Current status of intensity-modulated radiation therapy (IMRT).
abstract: External-beam radiation therapy has been one of the treatment options for prostate cancer. The dose response has been observed for a dose range of 64.8-81 Gy. The problem of external-beam RT for prostate cancer is that as the dose increases, adverse effects also increase. Three-dimensional conformal radiation therapy (3D-CRT) has enabled us to treat patients with up to 72-76 Gy to the prostate, with a relatively acceptable risk of late rectal bleeding. Recently, intensity-modulated radiation therapy (IMRT) has been shown to deliver a higher dose to the target with acceptable low rates of rectal and bladder complications. The most important things to keep in mind when using an IMRT technique are that there is a significant trade-off between coverage of the target, avoidance of adjacent critical structures, and the inhomogeneity of the dose within the target. Lastly, even with IMRT, it should be kept in mind that a "perfect" plan that creates completely homogeneous coverage of the target volume and zero or small dose to the adjacent organs at risk is not always obtained. Participating in many treatment planning sessions and arranging the beams and beam weights create the best approach to the best IMRT plan.
authors: Division of Radiation Oncology, Chiba Cancer Center, Chiba, Japan. khatano@chiba-cc.jp
authors: Kazuo
authors: K
authors: Hatano
authors: Hitoshi
authors: H
authors: Araki
authors: Mitsuhiro
authors: M
authors: Sakai
authors: Takashi
authors: T
authors: Kodama
authors: Naoki
authors: N
authors: Tohyama
authors: Tohru
authors: T
authors: Kawachi
authors: Masaharu
authors: M
authors: Imazeki
authors: Takayuki
authors: T
authors: Shimizu
authors: Tsutomu
authors: T
authors: Iwase
authors: Minoru
authors: M
authors: Shinozuka
authors: Hideyo
authors: H
authors: Ishigaki
mesh_terms: D001918:Brachytherapy / Q000379:methods*; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods