ISSN 1004-4140
CN 11-3017/P

X射线能量对剂量计测量CT辐射剂量的影响

The Effect of X-ray Energy on Dosimeter Measurements of CT Radiation Dose

  • 摘要: 目的:使用Raysafe-X2空气电离室(简称“RX2”)、piranha CT dose profiler半导体电离室(简称“CDP”)和30013 Farmer 空气电离室(简称“PT3”)测量不同X射线能量下的点剂量和容积CT剂量指数(CTDIvol),探讨X射线能量对不同剂量计评估辐射剂量的影响。方法:逐层扫描管电压设置:单能量模式包括:80 kV、90 kV、100 kV、120 kV、140 kV和150 kV(Sn),双能量模式包括:70/150 kV(Sn)、80/150 kV(Sn)、90/150 kV(Sn)、100/150 kV(Sn)和80/140 kV。通过手动调节管电流,保证各组CTDIvol约为20 mGy,记录显示CTDIvol与DLP。使用CDP和PT3测量32 cm模体中心、0点、3点、6点和9点位点剂量值。使用RX2、CDP和PT3测量并计算实际CTDIvol。结果:(1)点剂量:①单能量模式(除Sn150 kV)时CDP在中心位置测得点剂量高于PT3。低能量时非中心位置,CDP测得的75%点剂量高于PT3;高能量时PT3测得的88%的点剂量高于CDP。②双能量模式(除90+Sn150 kV)时CDP在中心位置测得点剂量均高于PT3。除80+140 kV,非中心位置PT3测得点剂量高于CDP。(2)CTDIvol:RX2测量值为(18.89±0.38)mGy,CDP测量值为18.31(19.25,20.84)mGy,PT3测量值为(20.35±0.38)mGy。除使用CDP在150 kV(Sn)的射线能量下,余射线能量下三种剂量计测得CTDIvol均在16 mGy~24 mGy之间。结论:不同剂量计对射线能量的响应特性存在差异,因此在不同测量条件和测量目的下,选择合适的剂量计至关重要。

     

    Abstract: Objective: The point dose and volume CT dosimetry index (CTDIvol) at different X-ray energies were measured using the Raysafe-X2 air ionization chamber (referred to as “RX2”), the Piranha CT dose profiler semiconductor ionization chamber (referred to as “CDP”), and the 30013 Farmer air ionization chamber (referred to as “PT3”), in order to explore the effect of X-ray energy on the radiation dose evaluation by different dose meters. Methods : The tube voltage settings for each layer were as follows: single energy mode included 80 kV, 90 kV, 100 kV, 120 kV, 140 kV, and 150 kV (Sn); dual energy mode included 70/150 kV (Sn), 80/150 kV (Sn), 90/150 kV (Sn), 100/150 kV (Sn), and 80/140 kV. The tube current was manually adjusted to ensure that the CTDIvol for each group was approximately 20 mGy, and the displayed CTDIvol and DLP were recorded. Point dose values were measured at the center, 0-point, 3-point, 6-point, and 9-point positions of the 32 cm phantom using CDP and PT3. The actual CTDIvol was measured and calculated using RX2, CDP, and PT3. Results: (1) Point Dose:①in single energy mode (except for Sn150 kV), CDP measured higher point doses at the center compared to PT3. At low energies, the point dose measured by CDP at non-center positions was 75% higher than that of PT3, while at high energies, 88% of the point doses measured by PT3 were higher than those measured by CDP. ②In dual energy mode (except for 90+Sn150 kV), CDP measured higher point doses at the center compared to PT3. However, except for 80+140 kV, PT3 measured higher point doses than CDP at non-center positions. (2) As for CTDIvol, the measured values were as follows: RX2 measured (18.89 ± 0.38) mGy, CDP measured 18.31 (19.25, 20.84) mGy, and PT3 measured (20.35 ± 0.38) mGy. Except when CDP was used at 150 kV (Sn), the CTDIvol measured by all three dose meters for other X-ray energies ranged between 16 mGy and 24 mGy. Conclusion: Different dosimeters exhibit varying responses to X-ray energy. Therefore, selecting an appropriate dosimeter is crucial depending on the measurement conditions and objectives.

     

/

返回文章
返回