title: Effect of edema on the post-implant dosimetry of an I-125 prostate implant: a case study.
abstract: OBJECTIVE
  To investigate the effect of post-implant edema on the CT-based calculation of the total dose delivered by an I-125 prostate implant.
  
  
  METHODS
  CT scans of a transperineal I-125 prostate implant were obtained 1 and 39-days post-implant. Changes in the prostate dimensions were determined from changes in the spatial distribution of the I-125 seeds. The total dose delivered to the target volume was computed from each CT scan, and the results compared.
  
  
  RESULTS
  The volume of the prostate decreased by approximately 17% during the 38-day interval between the first and second CT scans. As a result, the radiation dose computed from the second CT scan was 13% higher.
  
  
  CONCLUSIONS
  Post-implant edema can cause a significant underestimation of the radiation dose delivered by an I-125 prostate implant. Similar analysis should be carried out among a larger cohort of patients to confirm or refute these observations.
authors.affiliation: Department of Radiation Oncology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: F M
authors.initials: FM
authors.lastname: Waterman
authors.forename: N
authors.initials: N
authors.lastname: Yue
authors.forename: S
authors.initials: S
authors.lastname: Reisinger
authors.forename: A
authors.initials: A
authors.lastname: Dicker
authors.forename: B W
authors.initials: BW
authors.lastname: Corn
mesh_terms: D000368:Aged; D001918:Brachytherapy; D004487:Edema / Q000473:pathology*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D011467:Prostate / Q000000981:diagnostic imaging / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D011859:Radiography; D011879:Radiotherapy Dosage
chemical_list: D007457:Iodine Radioisotopes