Abstract
An examination was made of the effect upon the minimum tumor dose of a limit placed on the variation of dose across target. If the required level of target dose uniformity is slightly relaxed, a substantial improvement in the minimum tumor dose might appear. It was conjectured that this effect could be seen with treatments optimally planned and evaluated in three-dimensions. A model of advanced carcinoma of the lung treated with a computer controlled accelerator was used to test this hypothesis. A mathematical program for optimizing beam weights was used to determine the largest minimum tumor dose possible. In the six cases tested, a minimum tumor dose of > 80 Gy could be delivered if a 20% inhomogeneity limit was accepted. The minimum tumor dose fell to the range 44-64 Gy when the inhomogeneity limit was tightened to 13-17%. The results imply a need to examine the choice of a required level of dose uniformity from the range of values suggested in the 2-dimensional planning literature. If a strict bound-on-dose uniformity is preserved, mechanisms - such as formal optimization - which can reduce target dose inhomogeneity will be valuable.
Original language | English (US) |
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Pages (from-to) | 245-256 |
Number of pages | 12 |
Journal | Radiotherapy and Oncology |
Volume | 21 |
Issue number | 4 |
DOIs | |
State | Published - Aug 1991 |
Externally published | Yes |
Keywords
- Computer controlled radiotherapy
- Lung cancer
- Optimized three-dimensional treatment
- Target dose
ASJC Scopus subject areas
- Hematology
- Oncology
- Radiology Nuclear Medicine and imaging