| Literature DB >> 29353666 |
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Abstract
Entities:
Year: 2018 PMID: 29353666 PMCID: PMC6859496 DOI: 10.1016/j.ijrobp.2017.11.005
Source DB: PubMed Journal: Int J Radiat Oncol Biol Phys ISSN: 0360-3016 Impact factor: 7.038
Dose constraints guidance used for 3D conformal planning for total prescription dose of 36Gy in 6 fractions
| Organ | Constraint | ||
|---|---|---|---|
| Rectum | 17Gy | 80% | |
| 28Gy | 60% | ||
| 33Gy | 50% | ||
| 36Gy | 30% | ||
| Femoral heads | 28Gy | 50% | |
| Other bowel | optimal | mandatory | |
| V25 | 139cc | 208cc | |
| V28 | 122cc | 183cc | |
| V31 | 105cc | 157cc | |
| V33 | 84cc | 126cc | |
| V36 | 26cc | 39cc | |
Proposed constraints are based on total prescription dose of 36Gy prescribed to 100% at the International Commission on Radiation Units and Measurements reference point. In those with advanced disease or limited performance status 30Gy in 5 fractions was considered (three patients planned to 30Gy in 5 fractions). Dose constraints were derived from previously recruited phase III studies (CHHIP and BC2001) using linear quadratic model assuming α/β of 10 for tumor control and 3 for normal tissue 2, 3, 4, 5. Organs at risk were contoured as solid structures by defining their outer wall on CT0. Other bowel constraints were specified only for the small plan and medium plan as it was expected that the large plan would exceed above constraints given the position of bowel on the planning CT scan is not reflective of true bowel position at treatment delivery when large plan would be selected for treatment.