Abstract
Basic dosimetric properties of 6 MV and 18 MV photon beams from a Varian Clinac 21EX accelerator operating without the flattening filter have been measured. These include dose rate data, depth dose dependencies and lateral profiles in a water phantom, total scatter factors and transmission factors of a multileaf collimator. The data are reviewed and compared with measurements for the flattened beams. The unflattened beams have the following: a higher dose rate by factors of 2.3 (6 MV) and 5.5 (18 MV) on the central axis; lower out-of-field dose due to reduced head scatter and softer spectra; less variation of the total scatter factor with field size; and less variation of the shape of lateral dose profiles with depth. The findings suggest that with a flattening filter free accelerator better radiation treatments can be developed, with shorter delivery times and lower doses to normal tissues and organs.
Original language | English (US) |
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Pages (from-to) | 1907-1917 |
Number of pages | 11 |
Journal | Physics in medicine and biology |
Volume | 51 |
Issue number | 7 |
DOIs | |
State | Published - Apr 7 2006 |
ASJC Scopus subject areas
- Radiological and Ultrasound Technology
- Radiology Nuclear Medicine and imaging