Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA.
Med Phys. 2011 Feb;38(2):736-42. doi: 10.1118/1.3533685.
Effective dose (E) is useful as a dose index for patient exposures in interventional radiology; therefore, the authors estimated E from the kerma-area product (P(KA)) utilized during hepatic embolization interventional radiology cases performed at a cancer center and determined the variation of such doses over a representative patient population.
A single-center, IRB-approved retrospective study was performed to estimate doses from consecutive hepatic embolization procedures performed during 2006. Organ doses E and E/P(KA) were determined from patient height, weight, P(KA), procedure geometry factors, beam quality, the PCXMC Monte Carlo model, and the International Commission on Radiological Protection organ weighting factors.
One hundred thirteen patients were included in the study population, 72 males and 41 females, with a median age of 63 yr (29-89 yr), weight of 79 kg (42-111 kg), height of 170 cm (147-188 cm), and P(KA) of 233 Gy cm2 (9-1020 Gy cm2). E was directly correlated with P(KA) r2 = 0.8 (p < 0.01), with a median E/P(KA) of 0.18 mSv Gy(-1) cm(-2) (0.12-0.33 mSv Gy(-1) cm(-2)). The E/P(KA) ratio was inversely and exponentially correlated with weight r2 = 0.9 (p < 0.001). The median E (mSv) for the study patient population was 44 mSv (2.0-255 mSv).
Values of E can be estimated utilizing patient-specific and procedure-specific parameters. The strong inverse correlation of E/P(KA) with patient weight allows simple estimation of E from P(KA) and patient weight. There is a wide variation in effective dose in oncologic hepatic embolizations with doses up to an order of magnitude higher than diagnostic imaging of the abdomen by CT radiology. Variation is likely due to patient geometry, clinical technique factors, and procedure complexity.
有效剂量（E）可用作介入放射学中患者照射的剂量指标；因此，作者从在癌症中心进行的肝栓塞介入放射学病例中使用的比释动能面积产物（P(KA)）估算 E，并确定在代表性患者人群中这些剂量的变化。
进行了一项单中心、IRB 批准的回顾性研究，以估算 2006 年连续进行的肝栓塞程序的剂量。从患者身高、体重、P(KA)、程序几何因素、束质、PCXMC 蒙特卡罗模型和国际放射防护委员会器官加权因子确定器官剂量 E 和 E/P(KA)。
研究人群包括 113 例患者，72 例男性和 41 例女性，中位年龄为 63 岁（29-89 岁），体重为 79kg（42-111kg），身高为 170cm（147-188cm），P(KA)为 233Gy·cm2（9-1020Gy·cm2）。E 与 P(KA)直接相关 r2=0.8（p<0.01），中位 E/P(KA)为 0.18mSv·Gy-1·cm-2（0.12-0.33mSv·Gy-1·cm-2）。E/P(KA)比值与体重呈负指数相关 r2=0.9（p<0.001）。研究人群的中位 E（mSv）为 44mSv（2.0-255mSv）。
可以利用患者特异性和程序特异性参数估算 E 值。E/P(KA)与患者体重的强烈负相关允许从 P(KA)和患者体重简单估算 E。在肿瘤性肝栓塞中，有效剂量存在很大差异，剂量比 CT 放射学腹部诊断成像高一个数量级。这种差异可能是由于患者的几何形状、临床技术因素和程序的复杂性。
