头颈部血管造影中采集野及附加滤过对受检者辐射剂量影响的体模研究

Impact on examinees dose with collection field and additional filtration in angiography of head and neck:Phantom study

目的探讨头颈部血管造影过程中采集野及附加滤过对受检者辐射剂量的影响。方法采用扫描仿真体模、热释光剂量计实测剂量,比较Philps Allura Xper FD20血管造影机的不同采集野(22、31、42、48cm)及附加滤过(0.1mmCu+1mmAl、0.4mmCu+1mmAl、0.9mmCu+1mmAl)组合下,2D-DSA及3D-DSA数据采集时的管电压、管电流、累积剂量面积乘积(DAP)、空气比释动能(AK)及各采集点的剂量值;并在单次曝光模式下,调整不同的采集野及附加滤过组合,分别对矩形波测试卡摄影,采集单幅图像,通过矩形波测试卡图像,探讨采集野及附加滤过与空间分辨率的相关性。结果 3D-DSA数据采集时采集野22cm,附加滤过0.1 mmCu+1 mmAl时,AK为103.90 mGy,垂体的吸收剂量为(13.48±0.12)mGy,枕骨入射皮肤剂量为(134.76±0.55)mGy,均为最大值;采集野48 cm,附加滤过0.9mmCu+1mmAl时,AK为15.00mGy,垂体的吸收剂量为(4.66±0.06)mGy,枕骨入射皮肤剂量为(21.30±0.26)mGy,均为最小值。3D-DSA数据采集时采集野为48cm,附加滤过为0.9mmCu+1mmAl和0.1mmCu+1mmAl时,矩形波测试卡显示值最低,为1.2Lp/mm;采集野为22cm,附加滤过为0.4 mmCu+1 mmAl时,矩形波测试卡显示值最高,为3.1Lp/mm。结论采用适中的采集野、适当增加附加滤过厚度,在保证图像空间分辨率的同时,可降低受检者辐射剂量。

Objective To investigate the impact on examinees dose with additional filtration and collection field in head and neck angiography. Methods Values of tube voltage, tube current, dose area product （DAP）, air kerma （AK） and radiation dose in each collection point with normal and three dimensional DSA model were collected and compared. All the data were measured in different combination of collection field （22, 31, 42, 48 cm）and additional filtration （0.1 mmCu＋1 mmAl, 0.4 mmCu＋1 mmAl, 0.9 mmCu＋1 mmAl） with scanning simulation model of Philps Allura Xper FD20 angiography machine. In a single exposure mode, the different gathering wild and additional filtration combination were adjusted respectively to the line to the photography, single image was collected, through the rectangular wave test card image, and the correlation of gathering wild and additional filtration with spatial resolution were discussed. Results In 3D-DSA scanning with 22 cm collecting wild and 0.1 mmCu＋1 mmAl additional filtration, the corresponding AK value and pituitary absorbed dose were 103.90 mGy and （13.48±0.12）mGy respectively, the entrance surface dose was （134.76±0.55）mGy, both were maximum value; 48 cm collecting wild and 0.9 mmCu＋1 mmAl additional filtration, the corresponding AK value and pituitary absorbed dose were 15.00 mGy and （4.66±0.06）mGy respectively, the entrance surface dose was （21.30±0.26） mGy, both were minimum value. In 3D-DSA scanning with 48 cm collecting wild, 0.9 mmCu＋1 mmAl or 0.1 mmCu＋1 mmAl additional filtration, rectangular wave test card display value showed the lowest value 1.2 Lp/mm, with 22 cm collecting wild, 0.4 mmCu＋1 mmAl, rectangular wave test card display value showed the highest value 3.1 Lp/mm. Conclusion This experiment showed that the moderate gathering wild and proper thickness of additional filtration would reduce the radiation dose while the space resolution of images was guaranteed.