title: The retrospective analysis of the relationship between prescribed dose and risk factor for seed migration in iodine-125 prostate brachytherapy.
abstract: OBJECTIVE
  The aim was to determine the dose-specific incidence and predictors of seed loss/migration after permanent seed implantation (PI) for localized prostate cancer.
  
  
  METHODS
  The records of 79 patients with T1c-T3a prostate cancer who underwent prostate brachytherapy with loose iodine-125 seeds were retrospectively reviewed. Of these patients, 33 with low or intermediate risk underwent PI with the prescribed dose of 160 Gy for the clinical target volume (CTV), and 46 with high risk underwent PI with 110 Gy for the CTV followed by external beam radiotherapy (EBRT) with 45 Gy. Each CTV was defined as a contoured prostate. After PI, the incidence of seed loss/migration was assessed by a series of radiographs.
  
  
  RESULTS
  Seed migration occurred in 22 (0.479 %) of 4589 implanted seeds 1 month after implantation. In PI alone, the number of needles (P = 0.081) and the number of seeds (P = 0.071) showed a trend for a difference between those with and without seed loss. In PI + EBRT, there was a significant difference in the discrepancy between the seed numbers calculated by the nomogram and actually implanted (P = 0.032).
  
  
  CONCLUSIONS
  It is suggested that the discrepancy in seed numbers might be the predictor for seed migration in PI with 110 Gy.
authors.affiliation: Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.|Department of Radiation Oncology, Southern Tohoku BNCT Research Center, 7-10 Yatsuyamada, Koriyama, Fukushima, 963-8052, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Hirose
authors.affiliation: Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan. maoki@hirosaki-u.ac.jp.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Aoki
authors.affiliation: Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Sato
authors.affiliation: Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Akimoto
authors.affiliation: Department of Urology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Hashimoto
authors.affiliation: Department of Urology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Imai
authors.affiliation: Department of Urology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
authors.forename: Noritaka
authors.initials: N
authors.lastname: Kamimura
authors.affiliation: Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Kawaguchi
authors.affiliation: Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
authors.forename: Yoshiomi
authors.initials: Y
authors.lastname: Hatayama
authors.affiliation: Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
authors.forename: Ichitaro
authors.initials: I
authors.lastname: Fujioka
authors.affiliation: Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
authors.forename: Mitsuki
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Department of Urology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
authors.forename: Chikara
authors.initials: C
authors.lastname: Ohyama
authors.affiliation: Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.|Department of Radiation Oncology, Southern Tohoku BNCT Research Center, 7-10 Yatsuyamada, Koriyama, Fukushima, 963-8052, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Takai
mesh_terms: D000368:Aged; D001918:Brachytherapy / Q000295:instrumentation*; D004307:Dose-Response Relationship, Radiation; D005548:Foreign-Body Migration / Q000000981:diagnostic imaging*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D007457:Iodine Radioisotopes
keywords: Brachytherapy; Permanent seed implantation; Prostate cancer; Seed migration