| Автор | Stefan A Johnsson |
| Автор | Crister P Ceberg |
| Автор | Per Nilsson |
| Дата выпуска | 2002-11-21 |
| dc.description | A calculation engine for independent checking of the delivered dose to the prescription point has been developed and tested in an earlier work by our group. One drawback with the present system is the inability to accurately predict the absorbed dose at the depth of dose maximum, d<sub>max</sub>, where calculations may deviate by as much as 6–7. Accurate dose values at d<sub>max</sub> are necessary in order to make comparisons with in vivo dose measurements. The aim of this work is to extend the present model to predict dose values at d<sub>max</sub> to within ±2. Depth dose measurements at different SSD (80, 90 and 100 cm) and field sizes (5 × 5 to 40 × 40 cm<sup>2</sup>) are made at photon energies in the range from 4 to 18 MV. The effect of an acrylic block tray present in the beam is also studied. Wedged beams are handled as separate beam qualities. An entrance dose factor is defined to correct the effect of electronic disequilibrium at d<sub>max</sub>. The entrance dose factor is found to be independent of SSD and tray, but it varies with beam quality and field size. After applying the entrance dose factor, the dose at d<sub>max</sub> can be predicted to within 1.7 (2 SD). |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | A simplistic formalism for calculating entrance dose in high-energy x-ray beams |
| Тип | paper |
| DOI | 10.1088/0031-9155/47/22/306 |
| Electronic ISSN | 1361-6560 |
| Print ISSN | 0031-9155 |
| Журнал | Physics in Medicine and Biology |
| Том | 47 |
| Первая страница | 3985 |
| Последняя страница | 3995 |
| Аффилиация | Stefan A Johnsson; Radiation Physics Department, Lund University Hospital, SE-221 85 Lund, Sweden |
| Аффилиация | Crister P Ceberg; Radiation Physics Department, Lund University Hospital, SE-221 85 Lund, Sweden |
| Аффилиация | Per Nilsson; Radiation Physics Department, Lund University Hospital, SE-221 85 Lund, Sweden |
| Выпуск | 22 |
