Abstract
We report new effective linear attenuation coefficients (μ eff) for refined gypsum for Co-60 and 18 MV x-rays. 6 MV and 10 MV μ eff agree with published data. For a 100 cm 2 field size (FS), tissue defect χ = 1.35 cm, target depth d = 1.65 cm beneath the tissue defect χ, μ eff is 0.123 cm -1 (Co-60) and 0.0934 cm -1 (6 MV). For 100 cm 2, χ = 1.35 cm, and d = 5.65 cm beneath χ, μ eff is 0.072 cm -1 (10 MV), and 0.0614 cm -1 (18 MV). For d, μ eff decreases about 10% from 25 to 400 cm 2. For a given FS, μ eff decreases with d by 3%-5% for Co-60, and 3% for 6 MV, 10 MV and 18 MV, but depends on (d - χ). For d, when χ is large (8 cm), depending on energy and FS, μ eff is 2%-4% less than when χ is small (2 cm). These data were used in a treatment-planning computer to design compensator filters for a step phantom. Compensation was to within 10% in the compensation plane (CP). Above and below CP, computer-calculated ratios of doses with and without filters were 0.75-1.13. Chamber dose ratios with and without filters were 0.75-1.12.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 63-71 |
| Number of pages | 9 |
| Journal | Physics in Medicine and Biology |
| Volume | 48 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 7 2003 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biomedical Engineering
- Physics and Astronomy (miscellaneous)
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology
Cite this
Refined gypsum effective attenuation coefficients for Co-60, 6 MV, 10 MV and 18 MV x-rays. / Glasgow, Glenn P.; Dogan, Nesrin; Sethi, Anil; Stanton, Jerry.
In: Physics in Medicine and Biology, Vol. 48, No. 1, 07.01.2003, p. 63-71.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Refined gypsum effective attenuation coefficients for Co-60, 6 MV, 10 MV and 18 MV x-rays
AU - Glasgow, Glenn P.
AU - Dogan, Nesrin
AU - Sethi, Anil
AU - Stanton, Jerry
PY - 2003/1/7
Y1 - 2003/1/7
N2 - We report new effective linear attenuation coefficients (μ eff) for refined gypsum for Co-60 and 18 MV x-rays. 6 MV and 10 MV μ eff agree with published data. For a 100 cm 2 field size (FS), tissue defect χ = 1.35 cm, target depth d = 1.65 cm beneath the tissue defect χ, μ eff is 0.123 cm -1 (Co-60) and 0.0934 cm -1 (6 MV). For 100 cm 2, χ = 1.35 cm, and d = 5.65 cm beneath χ, μ eff is 0.072 cm -1 (10 MV), and 0.0614 cm -1 (18 MV). For d, μ eff decreases about 10% from 25 to 400 cm 2. For a given FS, μ eff decreases with d by 3%-5% for Co-60, and 3% for 6 MV, 10 MV and 18 MV, but depends on (d - χ). For d, when χ is large (8 cm), depending on energy and FS, μ eff is 2%-4% less than when χ is small (2 cm). These data were used in a treatment-planning computer to design compensator filters for a step phantom. Compensation was to within 10% in the compensation plane (CP). Above and below CP, computer-calculated ratios of doses with and without filters were 0.75-1.13. Chamber dose ratios with and without filters were 0.75-1.12.
AB - We report new effective linear attenuation coefficients (μ eff) for refined gypsum for Co-60 and 18 MV x-rays. 6 MV and 10 MV μ eff agree with published data. For a 100 cm 2 field size (FS), tissue defect χ = 1.35 cm, target depth d = 1.65 cm beneath the tissue defect χ, μ eff is 0.123 cm -1 (Co-60) and 0.0934 cm -1 (6 MV). For 100 cm 2, χ = 1.35 cm, and d = 5.65 cm beneath χ, μ eff is 0.072 cm -1 (10 MV), and 0.0614 cm -1 (18 MV). For d, μ eff decreases about 10% from 25 to 400 cm 2. For a given FS, μ eff decreases with d by 3%-5% for Co-60, and 3% for 6 MV, 10 MV and 18 MV, but depends on (d - χ). For d, when χ is large (8 cm), depending on energy and FS, μ eff is 2%-4% less than when χ is small (2 cm). These data were used in a treatment-planning computer to design compensator filters for a step phantom. Compensation was to within 10% in the compensation plane (CP). Above and below CP, computer-calculated ratios of doses with and without filters were 0.75-1.13. Chamber dose ratios with and without filters were 0.75-1.12.
UR - http://www.scopus.com/inward/record.url?scp=0037422691&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0037422691&partnerID=8YFLogxK
U2 - 10.1088/0031-9155/48/1/305
DO - 10.1088/0031-9155/48/1/305
M3 - Article
VL - 48
SP - 63
EP - 71
JO - Physics in Medicine and Biology
JF - Physics in Medicine and Biology
SN - 0031-9155
IS - 1
ER -