title: A prospective quasi-randomized comparison of intraoperatively built custom-linked seeds versus loose seeds for prostate brachytherapy.
abstract: OBJECTIVE
  To compare dosimetric parameters, seed migration rates, operation times, and acute toxicities of intraoperatively built custom-linked (IBCL) seeds with those of loose seeds for prostate brachytherapy.
  
  
  METHODS
  Participants were 140 patients with low or intermediate prostate cancer prospectively allocated to an IBCL seed group (n=74) or a loose seed group (n=66), using quasirandomization (allocated by week of the month). All patients underwent prostate brachytherapy using an interactive plan technique. Computed tomography and plain radiography were performed the next day and 1 month after brachytherapy. The primary endpoint was detection of a 5% difference in dose to 90% of prostate volume on postimplant computed tomography 1 month after treatment. Seed migration was defined as a seed position >1 cm from the cluster of other seeds on radiography. A seed dropped into the seminal vesicle was also defined as a migrated seed.
  
  
  RESULTS
  Dosimetric parameters including the primary endpoint did not differ significantly between groups, but seed migration rate was significantly lower in the IBCL seed group (0%) than in the loose seed group (55%; P<.001). Mean operation time was slightly but significantly longer in the IBCL seed group (57 min) than in the loose seed group (50 min; P<.001). No significant differences in acute toxicities were seen between groups (median follow-up, 9 months).
  
  
  CONCLUSIONS
  This prospective quasirandomized control trial showed no dosimetric differences between IBCL seed and loose seed groups. However, a strong trend toward decreased postimplant seed migration was shown in the IBCL seed group.
authors.affiliation: Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Sagamihara, Japan. Electronic address: hishiyam@kitasato-u.ac.jp.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Ishiyama
authors.affiliation: Department of Urology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Takefumi
authors.initials: T
authors.lastname: Satoh
authors.affiliation: Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Kawakami
authors.affiliation: Department of Urology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Hideyasu
authors.initials: H
authors.lastname: Tsumura
authors.affiliation: Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Shouko
authors.initials: S
authors.lastname: Komori
authors.affiliation: Department of Urology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Tabata
authors.affiliation: Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Akane
authors.initials: A
authors.lastname: Sekiguchi
authors.affiliation: Department of Urology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Takahashi
authors.affiliation: Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Itaru
authors.initials: I
authors.lastname: Soda
authors.affiliation: Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Takenaka
authors.affiliation: Department of Urology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Iwamura
authors.affiliation: Department of Radiology and Radiation Oncology, Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Hayakawa
mesh_terms: D000328:Adult; D001918:Brachytherapy / Q000295:instrumentation* / Q000379:methods; D005548:Foreign-Body Migration / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D014057:Tomography, X-Ray Computed