Probability of receiving a high cumulative radiation dose and primary clinical indication of CT examinations: a 5-year observational cohort study

Abstract

ObjectiveHigh radiation exposure is a concern because of the association with cancer. The objective was to determine the probability of receiving a high radiation dose from CT (from one or more examinations within a 5-year period) and to assess the clinical context by evaluating clinical indications in the high-dose patient group.DesignObservational cohort study. Effective radiation dose received from one or more CT examinations within a predefined 5-year calendar period was assessed for each patient.SettingHospital setting.ParticipantsAll patients undergoing a diagnostic CT examination between July 2013 and July 2018 at the Maastricht University Medical Center.Primary and secondary outcome measuresThe primary outcome was the probability of receiving a high effective dose, defined as ≥100 mSv, from one or more CT examinations within 5 years as derived from a time-to-event analysis. Secondary outcomes were the clinical indication for the initial scan of patients receiving a high effective dose.Results100 672 CT examinations were performed among 49 978 patients including 482 (1%) who received a high radiation dose. The estimated probability of a high effective dose from a single examination is low (0.002% (95% CI 0.00% to 0.01%)). The 4.5-year probability of receiving a high cumulative effective dose was 1.9% (95% CI 1.6% to 2.2%) for women and 1.5% (95% CI 1.3% to 1.7%) for men. The probability was highest in age categories between 51 and 74 years. A total of 2711 (5.5%) of patients underwent more than six CT examinations, and the probability of receiving a high effective dose was 16%. Among patients who received a high effective dose, most indications (80%) were oncology related.ConclusionsThe probability of receiving a high radiation dose from CT examinations is small but not negligible. In the majority (80%) of high effective dose receiving patients, the indication for the initial CT scan was oncology related.

Analysis of repeated computed tomography scans and cumulative effective dose of patients in a hospital

“…A cumulative effective dose superior to 100 mSv represents a greater probability of causing effects due to radiation exposure [4,5]. When comparing this group of patients with the literature, the result is similar, with approximately 1% of patients fitting into these conditions (Table 1) [21][22][23][24]. Frequent repetitive CT scans for the same patient in a short period indicate the need for a more specific and individualized analysis to characterize this behavior.…”

A New Algorithm for Automatically Calculating Noise, Spatial Resolution, and Contrast Image Quality Metrics

“…3 A drawback of CT is the use of ionizing radiation, exposure to which may become high, in particular when accumulating from multiple scans. [4][5][6] Radiation dose optimization is necessary and even mandatory: radiation exposure per CT scan needs to be reduced while maintaining sufficient diagnostic image quality (IQ). 7,8 Finding the optimum balance between patient radiation exposure and IQ for each CT procedure is time consuming and not straightforward, particularly as there is no universal measure for clinical IQ.…”

“…Computed tomography (CT) has become an indispensable diagnostic tool in daily clinical practice, 1,2 and advances in the technology are ongoing 3 . A drawback of CT is the use of ionizing radiation, exposure to which may become high, in particular when accumulating from multiple scans 4–6 . Radiation dose optimization is necessary and even mandatory: radiation exposure per CT scan needs to be reduced while maintaining sufficient diagnostic image quality (IQ) 7,8 .…”