RESUMO
Mammography is the most effective way to detect breast abnormality among women. However, mammography is believed to be able to cause radiation induced carcinogenesis. Therefore dose measurement is important to estimate the risk and to control the quality of the image. This study was conducted to compare the average glandular dose (AGD) acquired by the breast phantom with two different anode/filter combination which are tungsten/rhodium (W/Rh) and tungsten/argentum (W/Ag). CIRS 012A breast phantom was exposed in craniocaudal (CC) projection using Hologic Selenia digital mammography system. Entrance surface air kerma (ESAK) was measured using thermoluminescent dosimeter (TLD). AGD was obtained from basic calculation of ESAK with conversion factors according to Euref protocol. Independent t-test showed significant difference in the mean AGD. The AGD for W/Rh is higher as compared to the AGD for W/Ag (p = 0.002, 95% CI: 0.22, 0.53). In conclusion, the use of W/Ag contributes to dose reduction during mammography examination.
RESUMO
Objective To compared intensity modulated radiation therapy (IMRT) with conventional radiotherapy(CR) for the left side breast cancer after breast-conserving surgery in regard to the homogeneity of dose in the target area, cardiac dose and irradiation volume in the target area. Methods Thirty-eight patients received inverse planning of IMRT with dynamic multi-leaf collimation (dMLC). Prescription dose was 46Gy in breast volume with X-ray, and added electron boost dose was 14Gy in the tumor bed, with a total dose of 60Gy. Clinical target volume(CTV) and heart were evaluated with dose-volume histograms(DVH) in the two plans, with the t test taken with SPSS 11.0. Results Average received dose of 95% breast volume(D 95) was (4541?34),(4517?62)cGy, volume of 105% of dose prescription(V 105%) was 17.5%?17.6%,29.4%?26.3%, while V 110% was 0.3%?0.8%,3.7%?8.2% with IMRT and CR, respectively. Received 30Gy by the heart(V 30) was 4.6%?4.3%,18.8%?12.2%(P