- 學位論文
郵寄玻璃劑量計方法計量乳房攝影劑量品保之可行性評估
The evaluation of mammographic dosage with RPLGD by mailing delivery
摘要
在台灣，女性因罹患乳癌之死亡人數高居十大死因之首，因應政府政策積極推廣45歲至69歲女性進行乳房攝影篩檢，架構精確之劑量驗證系統儼然成為一項重要議題。本研究使用新型照射發光玻璃劑量計(Radiophotoluminescent Glass Dosimeter, RPLGD)，型號為MMG-QC，經改良後體積變小，並且加載不同厚度鋁片，減少臨床操作的時間，因此本研究擬將玻璃劑量計運用在乳房攝影儀器的輻射品保工作，利用玻璃計量計架構建全的輻射品管制度。然郵寄玻璃劑量計至他國是否造成劑量之銳減與其他風險評估乃為此研究之課題。本研究亦搭配PMMA假體和乳房X光攝影之常用曝露條件，使用玻璃劑量計作為半值層測量工具，並且探討透過航空郵件委由日本千代田科技測量中心執行計讀劑量輸出值之可行性。在測量入射劑量時，MMG-QC和游離腔測量值的p-value小於0.001，兩者之間沒有顯著性差異。對於射束半值層評估的結果，熱發光劑量計有明顯低估的情形，而MMG-QC和游離腔之間的誤差範圍為0.41 %至0.63 %。在平均乳腺劑量的測量實驗中，當能量為30 kVp和32 kVp時，MMG-QC和游離腔之間的誤差始高於10%。由實驗結果顯示，MMG-QC能達到游離腔的準確度，且操作便利，價格相對低廉，適合作為乳房X光攝影劑量驗證工具。
並列摘要
Breast cancer was the fourth common form of cancer in women in Taiwan. The government recently had been trying to invite women who aged from 45 to 69 for mammography screening every two years. It had become an important issue to set an accurate dose verification system. Radiophotoluminescent glass dosimeter (RPLGD), MMG-QC, which had been smaller and loaded aluminum to reduce the time of clinical operations. We intended to use MMG-QC in medical exposure quality control in this study, estimated whether postal dosimetry audit caused reduction of the dose, and assess risk. We also used RPLGD to measure half-value layer with PMMA phantom and discussed the feasibility of commissioning to Chiyoda Technol Corporation for readout of dose by air mail. There was no significant measurement deviation of entrance surface dose (ESD) between MMG-QC and ionization chamber, and therefore the p-value was less than 0.001. Thermoluminescent dosimeters (TLDs) significantly underestimated for half-value layer measurement, but the deviation between MMG-QC and ionization chamber was 0.41 % to 0.63 %. When the energy was 30 kVp and 32 kVp, the measurement deviation of mean glandular dose between MMG-QC and ionization chamber was higher than 10%. MMG-QC could achieve the accuracy as well as ionization chamber, more convenient operation, and its price was relatively low, so that it was a sui表 tool for mammographic quality control.