Department of Clinical Radiology, Ludwig-Maximilians-University Munich, Munich, Germany.
Br J Radiol. 2013 Jan;86(1021):20120224. doi: 10.1259/bjr.20120224.
To compare radiation exposure and image quality of oncological staging multidetector CT (MDCT) examinations of the chest, abdomen and pelvis with and without iterative reconstruction (IR).
40 patients with known malignancy underwent staging CT examinations at two time points. Both CT scans were performed on the same scanner (SOMATOM® Definition Flash, Siemens Healthcare, Forchheim, Germany). For the baseline scan, the tube current-time product was set to 250 mAs [image reconstruction: filtered back projection (FBP)] and for the follow-up scan to 150 mAs [reconstruction: iterative reconstruction (IR)]. Effective radiation doses were estimated based on dose-length products for both baseline and follow-up. Noise measurements in defined regions were compared for FBP and IR. Images were also subjectively evaluated for image quality by three radiologists with different levels of experience.
Dose reduction was 44.4±8.2% for reduced-dose CT scans with IR compared with baseline with FBP. Image noise was not significantly different between images reconstructed with FBP and IR. The subjective quality of standard-dose FBP images and reduced-dose iteratively reconstructed CT images were identical.
Our results show the dose-reducing potential of IR of CT image data in oncological patients.
The algorithm tested in the present scientific study allows a >45% dose reduction at maintained image quality.
比较胸部、腹部和骨盆多排螺旋 CT(MDCT)肿瘤分期检查中使用和不使用迭代重建(IR)的辐射剂量和图像质量。
40 名已知患有恶性肿瘤的患者在两个时间点进行了分期 CT 检查。两次 CT 扫描均在同一台扫描仪(SOMATOM® Definition Flash,西门子医疗,Forchheim,德国)上进行。基线扫描的管电流-时间乘积设置为 250 mAs[图像重建:滤波反投影(FBP)],后续扫描设置为 150 mAs[重建:迭代重建(IR)]。根据基线和后续的剂量长度乘积估计有效辐射剂量。比较 FBP 和 IR 时,在定义的区域内进行噪声测量。由三位具有不同经验水平的放射科医生对图像质量进行主观评估。
与使用 FBP 的基线扫描相比,使用 IR 的低剂量 CT 扫描的剂量降低了 44.4±8.2%。使用 FBP 和 IR 重建的图像之间的噪声没有显著差异。标准剂量 FBP 图像和低剂量迭代重建 CT 图像的主观质量相同。
我们的研究结果表明,IR 算法可以降低肿瘤患者 CT 图像数据的辐射剂量。
本研究中测试的算法允许在保持图像质量的同时降低超过 45%的剂量。