Résumé
Objective To study the percentage depth dose difference (PDD) between Monte Carlo method and the measurement method.Methods Based on the detail treatment head structure designing by the manufacture,the BEAMnrc Monte Carlo code was used to simulate the 6 MV photon beams of a Siemens Primus linear accelerator.DOSXYZnrc program generated 6 MV X-ray parameters such as PDD,and it was measured by MP3 three-dimensional water of PTW corporation phantom.The deviation of PDD was calculated using formulas ((measured value-simulation algorithm value)/measured value × 100％).Results Distance from the surface of the water was less than 1.2 cm,the deviation of PDD was ＞ 2％.Distance from the surface greater than 1.2 cm,the deviation of PDD was ＜ 2％.Conclusion In the built-up areas,PDD obtained by the Monte Carlo simulation algorithm is more accurate.
Résumé
This study was performed to described morphology of mitral valve by observing and measuring anatomical structures of mitral valves in Korean which looked normal at autopsy, and to provided basic data the clinical application. The mean circumference of mitral valve annulus was 9.14±1.28cm in males and 8.14±1.18cm in females. The width of anterior cusp was 30.3±0.53cm in males and 2.80±0.53cm in females, and the height was 1.99±0.43cm in males and 1.51±0.39cm in females. The posterior cusp consisted of 3 scallops in 34 hearts and 4 scallops in 4 hearts, and 2 scallops in 2 hearts out of 40 hearts. The middle scallop was largest in 36 hearts out of 40 hearts. The width of posteromedial scallop was 1.18±0.37cm in males and 1.08±0.32cm in females, and the height was 0.97±0.31cm in males and 0.94±0.29cm in females. Thre width of midd1e scallop was 2.08±0.61cm in males and 1.84±0.63cm in feamales, and the height was 1.18±0.32cm in male and 1,11±0.25cm in females. The width of anterolateral scallop was 1.30±0.41cm in males and 1.10±0.43cm in females, and the height was 0.88±0.25cm in males and 0.94±0.33cm in females. In general, the values of male were greater than those of female, although there was no statistical significance. Measurements of this study were generally smaller than those of the Caucasian reported by other investigators. Measurements in male were generally larger than those in female and this result corresponded well to those of other authors.