Kidoh Masafumi, Utsunomiya Daisuke, Oda Seitaro, Nakaura Takeshi, Funama Yoshinori, Yuki Hideaki, Hirata Kenichiro, Namimoto Tomohiro, Sakabe Daisuke, Hatemura Masahiro, Yamashita Yasuyuki
Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, 1-1-1, Honjo, Kumamoto, 860-8556, Japan.
Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, 1-1-1, Honjo, Kumamoto, 860-8556, Japan.
Eur Radiol. 2017 Jun;27(6):2267-2274. doi: 10.1007/s00330-016-4618-6. Epub 2016 Oct 7.
To investigate the usefulness of modifying scanning parameters based on the size-specific dose estimate (SSDE) for a breast-dose reduction for chest CT.
We scanned 26 women with a fixed volume CT dose index (CTDI) (15 mGy) and another 26 with a fixed SSDE (15 mGy) protocol (protocol 1 and 2, respectively). In protocol 2, tube current was calculated based on the patient habitus obtained on scout images. We compared the mean breast dose and the inter-patient breast dose variability and performed linear regression analysis of the breast dose and the body mass index (BMI) of the two protocols.
The mean breast dose was about 35 % lower under protocol 2 than protocol 1 (10.9 mGy vs. 16.8 mGy, p < 0.01). The inter-patient breast dose variability was significantly lower under protocol 2 than 1 (1.2 mGy vs. 2.5 mGy, p < 0.01). We observed a moderate negative correlation between the breast dose and the BMI under protocol 1 (r = 0.43, p < 0.01); there was no significant correlation (r = 0.06, p = 0.35) under protocol 2.
The SSDE-based protocol achieved a reduction in breast dose and in inter-patient breast dose variability.
• CT scan parameters can be modified based on the pre-scan SSDE. • The pre-scan SSDE is useful for a breast dose reduction. • The fixed SSDE protocol reduced individual variations in the breast dose.
研究基于体型特异性剂量估算（SSDE）调整扫描参数对胸部CT扫描中降低乳腺剂量的作用。
我们对26名女性采用固定容积CT剂量指数（CTDI）（15 mGy）进行扫描，对另外26名女性采用固定SSDE（15 mGy）方案进行扫描（分别为方案1和方案2）。在方案2中，根据定位像上获得的患者体型计算管电流。我们比较了平均乳腺剂量以及患者间乳腺剂量的变异性，并对两种方案的乳腺剂量与体重指数（BMI）进行线性回归分析。
方案2下的平均乳腺剂量比方案1低约35%（10.9 mGy对16.8 mGy，p < 0.01）。方案2下患者间乳腺剂量变异性显著低于方案1（1.2 mGy对2.5 mGy，p < 0.01）。我们观察到方案1下乳腺剂量与BMI之间存在中度负相关（r = 0.43，p < 0.01）；方案2下无显著相关性（r = 0.06，p = 0.35）。
基于SSDE的方案实现了乳腺剂量及患者间乳腺剂量变异性的降低。
• CT扫描参数可根据扫描前的SSDE进行调整。• 扫描前的SSDE对降低乳腺剂量有用。• 固定SSDE方案减少了乳腺剂量的个体差异。
