title: A dosimetric comparison of accelerated partial breast irradiation techniques: multicatheter interstitial brachytherapy, three-dimensional conformal radiotherapy, and supine versus prone helical tomotherapy.
abstract: OBJECTIVE
  To compare dosimetrically four different techniques of accelerated partial breast irradiation (APBI) in the same patient.
  
  
  METHODS
  Thirteen post-lumpectomy interstitial brachytherapy (IB) patients underwent imaging with preimplant computed tomography (CT) in the prone and supine position. These CT scans were then used to generate three-dimensional conformal radiotherapy (3D-CRT) and prone and supine helical tomotherapy (PT and ST, respectively) APBI plans and compared with the treated IB plans. Dose-volume histogram analysis and the mean dose (NTD(mean)) values were compared.
  
  
  RESULTS
  Planning target volume coverage was excellent for all methods. Statistical significance was considered to be a p value <0.05. The mean V100 was significantly lower for IB (12% vs. 15% for PT, 18% for ST, and 26% for 3D-CRT). A greater significant differential was seen when comparing V50 with mean values of 24%, 43%, 47%, and 52% for IB, PT, ST, and 3D-CRT, respectively. The IB and PT were similar and delivered an average lung NTD(mean) dose of 1.3 Gy(3) and 1.2 Gy(3), respectively. Both of these methods were statistically significantly lower than the supine external beam techniques. Overall, all four methods yielded similar low doses to the heart.
  
  
  CONCLUSIONS
  The use of IB and PT resulted in greater normal tissue sparing (especially ipsilateral breast and lung) than the use of supine external beam techniques of 3D-CRT or ST. However, the choice of APBI technique must be tailored to the patient's anatomy, lumpectomy cavity location, and overall treatment goals.
authors.affiliation: Department of Human Oncology, University of Wisconsin, Madison, WI, USA. patel@humonc.wisc.edu
authors.forename: Rakesh R
authors.initials: RR
authors.lastname: Patel
authors.forename: Stewart J
authors.initials: SJ
authors.lastname: Becker
authors.forename: Rupak K
authors.initials: RK
authors.lastname: Das
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Mackie
mesh_terms: D001918:Brachytherapy / Q000295:instrumentation / Q000379:methods*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000532:radiotherapy* / Q000601:surgery; D002404:Catheterization / Q000295:instrumentation / Q000379:methods; D006801:Humans; D015412:Mastectomy, Segmental; D016684:Prone Position; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D016683:Supine Position; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome