title: Accelerated partial breast irradiation dosimetric criteria for the strut-adjusted volume implant.
abstract: Current guidelines for high-dose-rate accelerated partial breast irradiation using single-entry implants are based on the National Surgical Adjuvant Breast and Bowel Project B-39/Radiation Therapy Oncology Group 0413 protocol, which assumed a balloon implant geometry. We have developed robust plan evaluation criteria specifically for the strut-adjusted volume implant (SAVI).
  
  
  
  Plan evaluation criteria were established using a "training data set" of 62 SAVI treatment plans and included the percentage volume of target receiving 90%, 95%, and 100% of the prescription dose (V90, V95, and V100), the absolute volume of target receiving 150% and 200% of prescription (V150 and V200), and the maximum doses to skin (Dskin max) and ribs (Drib max). "Ideal" and "expected" (routinely achievable) thresholds were determined for each criterion and compared to B-39 guidelines. A "test data set" collected from the next 25 patients was analyzed using the developed plan evaluation criteria.
  
  
  
  Ideal (expected) dosimetric thresholds established from the training data set were V90 ≥ 98% (95%), V95 ≥ 95% (92%), V100 ≥ 91% (88%), Dskin max < 90% (100%), and Drib max < 100%. Thresholds for V150 and V200 were stratified by SAVI size: V150 ≤ 30 cc (50 cc) and V200 ≤ 15 cc (20 cc) for 6-1 and Mini; V150 ≤ 50 cc (50 cc) and V200 ≤ 20 cc (20 cc) for 8-1 and 10-1. There was no significant difference between the training and test data sets in the fractions of patients meeting the criteria. Overall, 58% and 95% of 87 plans met all ideal and all expected criteria, respectively.
  
  
  
  The plan evaluation criteria developed specifically for the SAVI device are robust, providing increased target coverage and increased skin sparing compared to B-39 guidelines.
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Mooney
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Altman
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Sharbacha
authors.initials: S
authors.lastname: Edward
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Jose
authors.initials: J
authors.lastname: Garcia-Ramirez
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Thomas
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Imran
authors.initials: I
authors.lastname: Zoberi
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Todd
authors.initials: T
authors.lastname: DeWees
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Daniel
authors.initials: D
authors.lastname: Mullen
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO. Electronic address: jzoberi@radonc.wustl.edu.
authors.forename: Jacqueline E
authors.initials: JE
authors.lastname: Zoberi
mesh_terms: D001918:Brachytherapy / Q000295:instrumentation / Q000379:methods* / Q000592:standards*; D001943:Breast Neoplasms / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D019736:Prostheses and Implants; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000592:standards*; D012867:Skin / Q000528:radiation effects
keywords: APBI; Breast brachytherapy; SAVI; Treatment planning