SIMULATION AND COMPARISON OF X-RAY SPECTRA IN DIAGNOSTIC RADIOGRAPHY BY IPEM 78, SPEKPY, XPECGEN, SPEKTR 3.0, AND EGSNRC MONTE CARLO

Abstract

This study presents the simulation results of the X-ray spectra of the
general diagnostic radiography unit by using five computer codes.

The general diagnostic machine was assessed by quality assurance testing.
The half-value layer (HVL), mean energy (E_mean),  and Air kerma per mAs (K_air/mAs) have been measured and compared with those obtained from five computer codes. The heel effect and target material composition were investigated. The IPEM report No.78 was used as a reference to compare with other computer codes. 

The HVL, E_mean, K_air/mAs, and spectra were caused by five computer codes
and the measurements showed that all have good agreement with the IPEM report
No.78 and IEC 60601-1-3. The percentage differences (Diff, %) for HVL comparison
vary between 1,16 to 3,71% for 70kVp, 0,64 to 3,61% for 80kVp, 0,11 to 3,13% for
90kVp. The Diff, % in E_mean comparison vary between 0,24 to 8,95% for 70kVp,
0,07 to 6,29% for 80kVp, 0,08 to 7,0% for 90kVp. The Diff, % in K_air/mAs
comparison vary between 2,60 to 8,12% for 70kVp, 1,70 to 7,90% for 80kVp, 2,40
to 7,84% for 90kVp. For the anode heel effect, K_air/mAs is higher towards the cathode
side and lower towards the anode side, and the difference is lower when aluminium
filters are added.

The X-ray spectrum obtained by SpekPy is in the best agreement with
IPEM report No.78 while Xpecgen, Spektr 3.0, EGSnrc MC show a significantly lower
K-peaks intensity for 80 and 90kVp. The comparative assessment showed that the
HVL, E_mean and K_air/mAs were well-matched between the five codes and physical
measurements.