Abstract
This study compared the variations of depth and surface dose on beam angle between the unflattened and flattened photon beams. Monte Carlo simulation based on the EGSnrc code was used in dose calculation. Phase-space files of the 6 MV photon beams (field size = 10 × 10 cm2) were generated with and without the flattening filter based on a Varian TrueBeam Linac. Depth and surface doses were calculated in a water phantom with angles of the photon beams turning from 0° to 15°, 30°, 45°, 60°, 75° and 90°. Our results showed that compared to the flattened photon beam, the unflattened beam had a higher dose in the build-up region but lower dose beyond the depth of maximum dose. With the Monte Carlo beams cross-calibrated to the machine monitor unit in simulations, dose ratios of the unflattened to flattened beams were in the range of 1.6 – 2.6 with beam angles varying from 0° to 90° in water. In addition, higher surface doses of about 2.5 times were found with beam angles equal to 0o and 15o. However, surface dose deviation between the unflattened and flattened beam became smaller with an increase of beam angle. Using the photon fluence incorporated to the monitor unit, variations of depth and surface dose on the beam angle were investigated and compared. For the unflattened and flattened photon beams, the surface dose and range of depth dose ratios (unflattened to flattened beam) decreased with an increase of beam angle.
| Original language | English (US) |
|---|---|
| Title of host publication | World Congress on Medical Physics and Biomedical Engineering, 2015 |
| Publisher | Springer Verlag |
| Pages | 637-640 |
| Number of pages | 4 |
| Volume | 51 |
| ISBN (Print) | 9783319193878 |
| DOIs | |
| State | Published - Jan 1 2015 |
| Event | World Congress on Medical Physics and Biomedical Engineering, 2015 - Toronto, Canada Duration: Jun 7 2015 → Jun 12 2015 |
Other
| Other | World Congress on Medical Physics and Biomedical Engineering, 2015 |
|---|---|
| Country | Canada |
| City | Toronto |
| Period | 6/7/15 → 6/12/15 |
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Keywords
- Beam obliquity
- Dose calculation
- Flattening filter
- Monte Carlo simulation
- Skin dose
- Unflattened photon beam
ASJC Scopus subject areas
- Bioengineering
- Biomedical Engineering
Cite this
Dosimetric effect of beam angle on the unflattened and flattened photon beams : A monte carlo study. / Chow, James C.L.; Owrangi, Amir M.
World Congress on Medical Physics and Biomedical Engineering, 2015. Vol. 51 Springer Verlag, 2015. p. 637-640.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Dosimetric effect of beam angle on the unflattened and flattened photon beams
T2 - A monte carlo study
AU - Chow, James C.L.
AU - Owrangi, Amir M.
PY - 2015/1/1
Y1 - 2015/1/1
N2 - This study compared the variations of depth and surface dose on beam angle between the unflattened and flattened photon beams. Monte Carlo simulation based on the EGSnrc code was used in dose calculation. Phase-space files of the 6 MV photon beams (field size = 10 × 10 cm2) were generated with and without the flattening filter based on a Varian TrueBeam Linac. Depth and surface doses were calculated in a water phantom with angles of the photon beams turning from 0° to 15°, 30°, 45°, 60°, 75° and 90°. Our results showed that compared to the flattened photon beam, the unflattened beam had a higher dose in the build-up region but lower dose beyond the depth of maximum dose. With the Monte Carlo beams cross-calibrated to the machine monitor unit in simulations, dose ratios of the unflattened to flattened beams were in the range of 1.6 – 2.6 with beam angles varying from 0° to 90° in water. In addition, higher surface doses of about 2.5 times were found with beam angles equal to 0o and 15o. However, surface dose deviation between the unflattened and flattened beam became smaller with an increase of beam angle. Using the photon fluence incorporated to the monitor unit, variations of depth and surface dose on the beam angle were investigated and compared. For the unflattened and flattened photon beams, the surface dose and range of depth dose ratios (unflattened to flattened beam) decreased with an increase of beam angle.
AB - This study compared the variations of depth and surface dose on beam angle between the unflattened and flattened photon beams. Monte Carlo simulation based on the EGSnrc code was used in dose calculation. Phase-space files of the 6 MV photon beams (field size = 10 × 10 cm2) were generated with and without the flattening filter based on a Varian TrueBeam Linac. Depth and surface doses were calculated in a water phantom with angles of the photon beams turning from 0° to 15°, 30°, 45°, 60°, 75° and 90°. Our results showed that compared to the flattened photon beam, the unflattened beam had a higher dose in the build-up region but lower dose beyond the depth of maximum dose. With the Monte Carlo beams cross-calibrated to the machine monitor unit in simulations, dose ratios of the unflattened to flattened beams were in the range of 1.6 – 2.6 with beam angles varying from 0° to 90° in water. In addition, higher surface doses of about 2.5 times were found with beam angles equal to 0o and 15o. However, surface dose deviation between the unflattened and flattened beam became smaller with an increase of beam angle. Using the photon fluence incorporated to the monitor unit, variations of depth and surface dose on the beam angle were investigated and compared. For the unflattened and flattened photon beams, the surface dose and range of depth dose ratios (unflattened to flattened beam) decreased with an increase of beam angle.
KW - Beam obliquity
KW - Dose calculation
KW - Flattening filter
KW - Monte Carlo simulation
KW - Skin dose
KW - Unflattened photon beam
UR - http://www.scopus.com/inward/record.url?scp=84944322986&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84944322986&partnerID=8YFLogxK
U2 - 10.1007/978-3-319-19387-8_155
DO - 10.1007/978-3-319-19387-8_155
M3 - Conference contribution
AN - SCOPUS:84944322986
SN - 9783319193878
VL - 51
SP - 637
EP - 640
BT - World Congress on Medical Physics and Biomedical Engineering, 2015
PB - Springer Verlag
ER -