Pediatric Nuclear Medicine Examinations and Subsequent Risk of Neoplasm: A Nationwide Population-Based Cohort Study.

Objective: To evaluate the association between radiation exposure from repeated nuclear medicine (NM) examinations and the subsequent risk of neoplasm in pediatric patients. Methods: From 2000 to 2017, participants under 18 years of age who underwent NM scanning were identified using the Health and Welfare Data Science Center (HWDC) dataset, which was extracted from the Taiwan National Health Insurance Research Database (NHIRD). Both the exposed cohort and unexposed subjects were followed up with until the presence of any malignancy arose, including malignant brain, lymphoid and hematopoietic tumors and benign brain or other central nervous tumors. Results: There were 35,292 patients in the exposed cohort and 141,152 matched subjects in the non-exposed group. The exposed cohort had an overall higher IR (IR: incidence rate, per 100,000 person-years) of any malignancy and benign central nervous tumor than the non-exposed group [IR, 16.9 vs. 1.54; adjusted hazard ratio (HR), 10.9; 95% CI, 6.53-18.2]. Further stratifying the number of NM examinations into 1-2, 3-4, and 5 or more times revealed that the IR of pediatric neoplasms increased gradually with the increased frequency of NM examinations (IR, 11.5; adjusted HR, 7.5; 95% CI, 4.29-13.1; IR, 25.8; adjusted HR, 15.9; 95% CI, 7.00-36.1; IR, 93.8; adjusted HR, 56.4; 95% CI, 28.8-110.3). Conclusion: NM examination is significantly associated with a higher risk of pediatric neoplasms, according to our population-based data. Thorough radiation protection and dose reduction in pediatric NM procedures should be an issue of concern.

The risk of cataract associated with repeated head and neck CT studies: a nationwide population-based study.

OBJECTIVE: Medical radiation-induced cataracts, especially those resulting from head and neck CT studies, are an issue of concern. The current study aimed to determine the risk of cataract associated with repeated radiation exposure from head and neck CT. MATERIALS AND METHODS: This study used information from a random sample of 2 million persons enrolled in the nationally representative Taiwan National Health Insurance Research Database. Exposed cases consisted of patients with head and neck tumor 10-50 years old who underwent at least one CT between 2000 and 2009. The nonexposed control group was composed of subjects who were never exposed to CT studies but who were matched by time of enrollment, age, sex, history of coronary artery disease, hypertension, and diabetes. RESULTS: There were 2776 patients in the exposed group and 27,761 matched subjects in the nonexposed group. The exposed group had higher overall incidence of cataracts (0.97% vs 0.72%; adjusted hazard ratio [HR], 1.76; 95% CI, 1.18-2.63). Further stratifying the number of CT studies in the exposed group into one or two, three or four, and five or more revealed that cataract incidence increased gradually with increasing frequency of CT studies (0.79%, 0.93%, and 1.45%, respectively) (p=0.001, adjusted for trend). Radiation exposure due to repeated head and neck CT studies was independently associated with an increased risk of developing cataracts when the cumulative CT exposure frequency involved more than four studies (adjusted HR, 2.12; 95% CI, 1.09-4.14). CONCLUSION: Repeated exposure to head and neck CT is significantly associated with increased risk of cataract.