title: Three-dimensional dose distribution of total body irradiation by a dual source total body irradiator.
abstract: This study describes the three-dimensional dosimetric characteristics of total body irradiation by our dedicated irradiation unit, which consists of two modified 4-MV linear accelerators mounted opposite each other, providing a field size of 220 cm x 80 cm at the midplane. Our dose calculation algorithm considers the three-dimensional contour of the patient to evaluate the primary and scatter doses. The data base for the calculation includes tissue-to-maximum ratios measured for the large fields. The lung dose correction was calculated using the methods of Batho or ratio of TMR. The accuracy of the calculated dose distributions was verified by measurements with ionization chambers in a humanoid phantom. We also describe and verified a technique to achieve desirable midline lung doses using lead shields. The flexibility and the accuracy of the planning system offers the potential in optimizing the therapeutic ratio for total body treatments.
authors.affiliation: Department of Radiation Therapy, Harvard Medical School, Boston, MA.
authors.forename: C H
authors.initials: CH
authors.lastname: Obcemea
authors.forename: R K
authors.initials: RK
authors.lastname: Rice
authors.forename: B J
authors.initials: BJ
authors.lastname: Mijnheer
authors.forename: R L
authors.initials: RL
authors.lastname: Siddon
authors.forename: N J
authors.initials: NJ
authors.lastname: Tarbell
authors.forename: P
authors.initials: P
authors.lastname: Mauch
authors.forename: L M
authors.initials: LM
authors.lastname: Chin
mesh_terms: D000465:Algorithms; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008168:Lung / Q000528:radiation effects; D011829:Radiation Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D014916:Whole-Body Irradiation