Results and analysis of examination doses for paediatric CT procedures based on a nationwide survey in China.

OBJECTIVE: To report the results of a dose survey conducted across 31 provinces in mainland China from 2017 to 2018 and to analyse the dose level to determine the national diagnostic reference levels (DRLs) for paediatric CT procedures. METHODS: At least ten patients for each age group (0- < 1, 1- < 5, 5- < 10, 10- < 15 years) and each procedure (head, chest and abdomen) for each CT scanner were selected from four to eight hospitals in each province. The dose information (CTDIvol and DLP) was collected from the HIS or RIS-PACS systems. The median values in each CT scanner were considered the representative dose values for the paediatric patients in CT scanning. The national DRLs were estimated based on the 75th percentile distribution of the median values. RESULTS: A total of 24,395 patients and 319 CT scanners were investigated across 262 hospitals. For paediatric CT scanning in 4 different age groups, the median (P50) and the 75th percentile (P75) of CTDIvol and DLP for each scanning procedure were calculated and reported. National DRLs were then proposed for each procedure and age group. CONCLUSION: The dose level of CT scanning for children in mainland China was reported for the first time. The DRLs for paediatric CT in the present study are similar to those in some Asian countries but higher than those in European countries. CLINICAL RELEVANCE STATEMENT: The paediatric CT is an extensively used tool in diagnosing paediatric disease; however, children are more sensitive to radiation. Establishing the diagnostic reference level of paediatric CT examination is necessary to reduce the dose of CT in children and promote the optimisation of medical exposure. KEY POINTS: • The DRLs for 3 paediatric CT procedures (head, chest and abdomen) and 4 age groups (0- < 1, 1- < 5, 5- < 10, 10- < 15 years) were proposed in mainland China first time. • The examination parameter and dose for children need to be further optimised in China, especially to lower the tube voltage in paediatric CT.

Perioperative Measurement of Radiation Exposure to Radiation-Sensitive Organs of Patients Undergoing Lumbar Surgeries Using a Thermoluminescent Dosimeter.

OBJECTIVE: To introduce a method of accurately measuring the equivalent dose received by radiation-sensitive organs using the thermoluminescent dosimeter (TLD) and to provide reference values for future studies associated with radiation protection in patients undergoing lumbar spine surgeries. METHODS: After careful selection and preparation, TLD chips were used to obtain measurements from the eyes, thyroid glands, breasts, and gonads of 20 patients undergoing lumbar spine surgeries. The results were obtained via air kerma conversion-related calculations. RESULTS: The overall radiation exposures absorbed perioperatively by the eyes, thyroid glands, right breasts, left breasts, right ovaries, left ovaries, and testes were 0.41 ± 0.13, 1.43 ± 0.45, 6.95 ± 3.63, 9.50 ± 6.14, 29.86 ± 28.62, 23.47 ± 22.10, and 5.41 ± 1.86 mSv, respectively. A single computed tomography (CT) scan contributed to more than 75% of the overall dose received regardless of the position used. CONCLUSIONS: Patients received significantly higher radiation doses from CT scans than from regular digital radiograph examinations. These radiation doses were concentrated in the regional area of scanning. Our results indicate the necessity and benefits of radiation protection measures, especially for the organs researched herein, when patients undergoing lumbar surgeries require radiographic diagnostic examinations.