LATERAL ELECTRON EQUILIBRIUM AND ELECTRON CONTAMINATION IN MEASUREMENTS OF HEAD-SCATTER FACTORS USING MINIPHANTOMS AND BRASS CAPS

被引：74

作者：

LI, XA ^{[1
]}

SOUBRA, M ^{[1
]}

SZANTO, J ^{[1
]}

GERIG, LH ^{[1
]}

机构：

[1] UNIV OTTAWA,DEPT RADIOL,OTTAWA,ON,CANADA

来源：

MEDICAL PHYSICS | 1995年 / 22卷 / 07期

关键词：

D O I：

10.1118/1.597508

中图分类号：

R8 [特种医学]; R445 [影像诊断学];

学科分类号：

1002 ; 100207 ; 1009 ;

摘要：

The head-scatter factor (S-h) can be measured with a narrow miniphantom or a metal cap provided it is completely covered by the photon beam and its lateral size is thick enough to prevent electron contamination contributions. The effects of lateral electron equilibrium (LEE) and electron contamination on the S-h values were studied. The EGS4 Monte Carlo technique was used to calculate the minimum beam radii (gamma(LEE)) required to achieve complete LEE for photon beams ranging from Co-60 to 24 MV. The measurement shows that the error introduced to the S-h value due to lateral electron disequilibrium is negligible. The radii of the miniphantoms or the sidewall thicknesses of the caps can be reduced below gamma(LEE) provided they are thick enough to prevent the effect of electron contamination.

引用

页码：1167 / 1170

页数：4

共 21 条

[1]

[Anonymous], 1983, MED PHYS, V10, P741

[2]

[Anonymous], [No title captured]

[3]

BIELAJEW AF, 1987, NUCL INSTRUM METH B, V18, P165

[4]

BJARNGARD BE, 1993, MED PHYS, V20, P357, DOI 10.1118/1.597076