Premium
Sci‐Fri PM: Radiation Therapy, Planning, Imaging, and Special Techniques ‐ 07: Transitioning from extended‐distance total body irradiation to optimized VMAT total marrow irradiation
Author(s) -
Cherpak Amanda,
ChytykPraznik Krista,
Yewondwossen Mammo,
Schella Jason,
Davis CarolAnne,
Day Allan,
DeGiobbi Jennifer,
McAloney Dave,
Mulroy Liam
Publication year - 2016
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4961850
Subject(s) - contouring , medicine , nuclear medicine , bolus (digestion) , radiation treatment planning , radiation therapy , bone marrow , total body irradiation , radiology , surgery , chemotherapy , computer science , computer graphics (images) , cyclophosphamide
Purpose: TMI targets only the bone marrow, with the intent of sparing normal tissues. The NSCC has recently implemented a TMI protocol which includes VMAT fields to treat the bone marrow from head to mid‐thigh and extended SSD POP fields to treat the lower legs. This work describes the commissioning and initial clinical results of the first reported VMAT TMI treatments in Canada. Methods: Detailed CT simulation, imaging, planning and treatment procedures were developed by a multi‐disciplinary team. Patients have 1 cm of bolus over the lower legs and 0.5 cm of bolus around the lower arms. The PTV includes all bone, except mandible, facial bones and hands, with the objective of V(12 Gy) > 90%. Detailed analysis of the influence of field overlap was performed to determine optimal field placement and image‐guidance tolerances. Results: PTV coverage was achieved for all cases as V(12 Gy) ranged from 90.4–96.3%. The minimum dose to the PTV, D(99%), ranged from 91.4–97.87% and V(90%Rx=10.8 Gy) ranged from 99.1–100.0%. The lungs, liver and heart had an average D mean of (7.8±0.3)Gy/(65±2)%, (7.6±0.7)Gy/(63±5)%, and (6.8±0.4)Gy/(56±4)% respectively. Conclusions: Commissioning required input and collaboration from all team members. Transitioning from TBI to TMI requires additional time for contouring, treatment planning, QA, and treatment. Patient benefit can however be seen in the quality of OAR sparing.