title: Treatment delays using an automated afterloading low-dose-rate brachytherapy system.
abstract: OBJECTIVE
  Low-dose-rate (LDR) brachytherapy is an integral treatment modality in radiation oncology. Clinical efficacy is based on experience with manual source loading and continuous dose delivery. With remote afterloading technology, sources may be loaded and unloaded during the treatment course to prevent radiation exposure to nursing staff members and visitors. The aim of this study was to investigate treatment interruptions in terms of frequency and duration as well as extension of the overall treatment time period. The potential clinical impact of treatment interruptions was also considered.
  
  
  METHODS
  The treatment records of 20 patients who underwent brachytherapy in the Indiana University Department of Radiation Oncology administered with a Selectron LDR remote afterloader were reviewed. Results were tabulated and analysis performed with respect to 1) the number of interruptions, 2) delay time, 3) delay time (T(d)) as a function of total implant time (T), 4) the time of day that each interruption occurred, and 5) the time in minutes of each individual interruption.
  
  
  RESULTS
  The mean number of interruptions was 44.9 per patient, (range, 24-76), with a mean prescription implantation duration of 45.7 hours and a mean actual treatment time of 51.2 hours resulting in a mean interruption time of 6.4 minutes per treatment hour. The number of interruptions was standardized and divided by the number of prescribed dose in grays, translating to 1.2 to 3.7 interruptions per gray delivered, with a mean of 1.6, resulting in an average T(d) of 11.21% (range, 7.35%-17.12%).
  
  
  CONCLUSIONS
  Significant interruptions are frequent using remote afterloading LDR techniques, reducing the effective dose rate. Careful monitoring of such interruptions is warranted.
authors.affiliation: Department of Radiation Oncology, Indiana University School of Medicine/Melvin and Bren Simon Cancer Center, 535 Barnhill Drive, RT041, Indianapolis, IN 46202, USA. cmdesros@iupui.edu
authors.forename: Colleen M
authors.initials: CM
authors.lastname: DesRosiers
authors.forename: Eric
authors.initials: E
authors.lastname: Slessinger
authors.forename: Jeanne
authors.initials: J
authors.lastname: Schilder
authors.forename: Frederick
authors.initials: F
authors.lastname: Stehman
authors.forename: Indra J
authors.initials: IJ
authors.lastname: Das
authors.forename: Paul
authors.initials: P
authors.lastname: DesRosiers
authors.forename: Higinia
authors.initials: H
authors.lastname: Cardenes
authors.forename: Peter A S
authors.initials: PA
authors.lastname: Johnstone
mesh_terms: D001918:Brachytherapy / Q000379:methods* / Q000706:statistics & numerical data*; D007196:Indiana; D011829:Radiation Dosage; D011879:Radiotherapy Dosage; D013997:Time Factors; D016526:Workload