Liao Eric A, Quint Leslie E, Goodsitt Mitchell M, Francis Isaac R, Khalatbari Shokoufeh, Myles James D
Department of Radiology, University of Michigan Health System, Ann Arbor, MI 48109-5030, USA.
J Comput Assist Tomogr. 2011 Jan-Feb;35(1):50-6. doi: 10.1097/RCT.0b013e3181f5a652.
To assess the degree of extra scanning beyond the prescribed anatomic boundaries for thoracic and body computed tomographic (CT) scans and to identify associated factors.
For 442 consecutive chest, abdomen, and/or pelvis CT examinations, the length of extra scanning beyond the prescribed anatomic boundaries was determined. Examinations were grouped according to the locations/types of the prescribed boundaries and compared with regard to length of extra scanning.
Of 442 CT examinations, 438 (99%) included extraneous imaging, showing a mean excess scanning length of 43.2 mm per examination (range, 0-180 mm). Significantly more extraneous imaging was performed when soft tissue or vascular structures defined anatomic boundaries compared to when osseous (P < 0.001) or air/soft tissue interfaces (P < 0.0001) defined the boundaries. The average percent of total scan dose attributable to extra imaging was 8.64% to 10.38%.
Computed tomographic scanning beyond the prescribed anatomic boundaries occurs commonly, resulting in moderate extra radiation dose.
评估胸部和体部计算机断层扫描（CT）超出规定解剖边界的额外扫描程度，并确定相关因素。
对连续442例胸部、腹部和/或骨盆CT检查，确定超出规定解剖边界的额外扫描长度。根据规定边界的位置/类型对检查进行分组，并比较额外扫描的长度。
在442例CT检查中，438例（99%）包含额外成像，每次检查的平均额外扫描长度为43.2mm（范围为0 - 180mm）。与骨结构（P < 0.001）或空气/软组织界面（P < 0.0001）定义边界时相比，当软组织或血管结构定义解剖边界时，进行的额外成像明显更多。额外成像所致总扫描剂量的平均百分比为8.64%至10.38%。
超出规定解剖边界的计算机断层扫描很常见，会导致适度的额外辐射剂量。
