Multicentric study of patients receiving 50 or 100 mSv in a single day through CT imaging-frequency determination and imaging protocols involved

Abstract

Objectives To assess the magnitude and characterization of CT imaging protocols of patients receiving 50 or 100 mSv in a single day. Methods In this multicentric retrospective study covering up to 279 hospitals from January 2015 to December 2019, the effective dose (E) as estimated by dose management system from dose length product of patients was filtered and grouped into per-day dose bands (<= 20, > 20-50, > 50-70, > 70-100, > 100-200, > 200 mSv). Information on patient's age and imaging protocol was noted. The data were analyzed to determine the frequency of occurrence in each dose band. Top 20 CT imaging protocols that led to patients with a dose of >= 50 mSv in a single acquisition were identified and their relative frequency was estimated. Results A total of approx. 4.3 million (4,283,738) CT exams were performed in approx. 3.9 million (3,880,524) patient-days indicating 9.41% had more than one CT exam in a single day. There were 31,058 (0.8%) patient-days with >= 50 mSv and 1191 (0.03%) with >= 100 mSv. Nearly 1/3(rd) patient-days reaching >= 50 mSv were of patients aged 50 years or younger. The top 20 CT imaging protocols that led to >= 50 mSv in a single day belonged to the body region (chest or abdomen and pelvis) and nearly one-third were angiographic studies. Conclusions In the first study of its kind, we report that patients with 50 mSv+ in a single day or a single exam are not rare. The information on imaging protocols leading to such doses and their frequency has been provided to help develop dose management strategies.