不同年齡層擬人型假體常規攝影劑量差異與探討

Evaluation different age groups anthropomorphic phantom organ dose with conventional Radiography procedure

林哲宇(Che-Yu Lin)

指導教授 ： 邵佳和

中山醫學大學/醫學科技學院/醫學影像暨放射科學系/碩士(2019年)

https://doi.org/10.6834/CSMU201900083

摘要

研究目的：
本研究的主要目的為觀察不同年齡之患者於一般診斷攝影中所得到的劑量差異，我們使用臨床上常見的攝影法並透過擬人型假體進行攝影曝露，以觀察不同假體在攝影法變化與合併性腺擋片置放下，對器官劑量及有效劑量所造成的影響。

材料與方法：
本研究使用三種不同年齡層之擬人型假體，分別為5歲兒童、10歲兒童以及成人，依據臨床上各年齡層患者較常使用的頸椎、胸部、腹部、腰椎以及全椎體等攝影法，透過TLD-100H測量所有攝影法對於各假體造成的器官劑量與有效劑量，同時測量所有攝影法的入射表面劑量(Entrance surface dose, ESD)，將器官劑量與有效劑量除上ESD去除攝影條件的影響，以觀察不同假體間劑量的差異。

結果與討論：
在所有攝影法中對於輻射照野內的器官之器官劑量，所得到的趨勢為成人假體最大，其次為10歲假體，最小為5歲假體。有效劑量方面，在成人假體中最大有效劑量為Abdomen 559.75/610.42 μSv(♂/♀)，最小為C-spine RAO 43.72 μSv(♂&♀)；在10歲假體中最大有效劑量為Chest Lateral 291.12 μSv(♂&♀)，最小為C-spine Lateral 27.31 μSv(♂&♀)；在5歲假體中最大有效劑量為Whole spine AP 107.22/110.27 μSv(♂/♀)，最小為C-spine Lateral 9.81 μSv(♂&♀)。每單位ESD造成的器官劑量與有效劑量方面，除了C-spine Lateral與Chest Lateral，其餘攝影法中兩具兒童假體都有大於成人假體的趨勢。
於合併使用性腺擋片之腹部檢查中，性腺擋片對10歲假體有最佳的性腺保護效果，其女性性腺器官劑量降低了58.5%；而對於成人假體的保護效果次之，其女性性腺器官劑量降低了40%；在5歲兒童假體保護效果最差，其女性性腺器官劑量僅降低了20.4%。

結論：
對於大部分的攝影法，每單位曝露量造成兒童假體的劑量均有大於成人假體的趨勢，這表示了即使兒童使用的攝影條件低而造成較低的劑量，但調整攝影條件造成兒童的劑量增加幅度卻是比較大的，因此建議於臨床上必須更加小心調控兒童的攝影參數。

關鍵字

一般診斷 ； 擬人型假體 ； 入射表面劑量 ； 器官劑量 ； 有效劑量

並列摘要

Purpose：
The purpose of this study is to observe the difference in dose between patients of different ages in diagnostic radiography. We use clinical radiography and expose through anthropomorphic phantom. To observe the effects of the organ dose and effective dose of different phantom during different radiography and using gonads shield.

Material & Method：
This study used anthropomorphic phantom of three different age groups, 5 years old, 10 years old, and adult respectively. According to the clinical radiography of C-spine, Chest, Abdomen, L-spine and Whole spine radiography and using TLD-100H to measure the organ dose and effective dose of all radiography for each phantom. At the same time, we measure Entrance surface dose(ESD) of all radiography and the organ dose and effective dose are divided by ESD to remove the effects of radiography to observe differences in doses between different phantom.

Result & discussion：
In all radiography, the organ dose for organs in the radiation field is the largest for adult phantom, followed by 10 y/o phantom and the least for 5 y/o phantom.
In terms of effective dose, the maximum effective dose in adult phantom is Abdomen 559.75/610.42 μSv (♂/♀), and the minimum is C-spine RAO 43.72 μSv (♂·♀); the maximum effective dose in 10 y/o phantom is Chest Lateral 291.12 μSv (♂ & ♀), the minimum is C-spine Lateral 27.31 μSv (♂ & ♀); the maximum effective dose in 5 y/o phantom is Whole spine AP 107.22/110.27 μSv (♂ / ♀), the minimum is C-spine Lateral 9.81 μSv (♂ & ♀).
In terms of organ dose and effective dose per unit of ESD, in addition to C-spine Lateral and Chest Lateral, the two pediatric phantom in the other radiography have a tendency to be larger than adult phantom.
In the Abdomen with using gonad shield, 10 y/o phantom has the best gonad protection effect, and the female gonad organ dose is reduced by 58.5%; while the protective effect on the adult phantom is second, the female gonad organ dose was reduced by 40%; the 5 y/o phantom has the worst gonad protection effect , and the female gonadal dose was only reduced by 20.4%.

Conclusion：
For most radiography, the dose per unit exposure has a tendency for pediatric phantom to be larger than adult phantom. This indicates that even if the radiographic parameters used by children are low, resulting in lower doses, the adjustment of radiographic parameters causes the dose increase of children to be relatively large. Therefore, it is recommended to be more careful in clinical regulation of children's radiographic parameters.

並列關鍵字

general diagnosis radiography ； anthropomorphic phantom ； entrance surface dose ； organ dose ； effective dose

參考文獻

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