Analysis of CT doses to paediatric patients in four children′s hospitals in Shanghai / 中华放射医学与防护杂志

Objective:To study the distribution of CT doses to paediatric patients in Shanghai by investigating the CT dose parameters availiable in Shanghai′s children′s hospticals, and to provide the basis for establishing the diagnostic reference level for the paediatic patients subjected to CT scanning in Shanghai.Methods:In 2021, a general survey was carried out of the CT doses to the head, chest and abdomen of the scanned paediatric patients in four children′s hospitals in the municipality. The scanned paediatic patients were divided into four age groups of 0-, 1-, 5- and 10-15 years old, each with 30 subjects. The basic information were collected on the subjects, CT scanning parameters, volume CT dose index (CTDI vol) and dose length product (DLP). SPSS 16.0 was used to carry out statistical analysis of the differences in CTDI vol and DLP between different age groups at the same site and between different hospitals for the same age group at the same site. Results:The 75 th percentile values of CTDI vol and DLP for 0-, 1-, 5- and 10-15 age groups were 25, 25, 28, 43 mGy and 402, 477, 504, 752 mGy·cm, respectively, for head scanning; 2.7, 2.2, 2.8, 5.4 mGy and 40, 48, 75 and 176 mGy·cm for chest; and 4.9, 4.4, 8.2, 12 mGy and 106, 131, 273, 471 mGy·cm for abdomen. There were significant differences in CTDI vol and DLP between different age groups at the same site and between different hospitals for the same age group at the same site (head, chest and abdomen CTDI vol:χ2=221.68, 167.27, 127.07, DLP: χ2=220.63, 261.46, 216.61; for four age groups, CTDI vol: head χ2=30.46, 38.39, 25.21, 73.04, chest χ2=30.46, 35.69, 58.92, and 48.03, abdomen χ2=66.58, 41.62, 48.93, and 67.38; DLP: head χ2=28.82, 72.49, 47.72, 52.34, chest χ2=28.82, 35.95, 50.66, 41.64, abdomen χ2=45.53, 26.02 39.34, 44.24, P <0.05 ). Conclusions:The 75 th percentile values of CTDI vol and DLP for head, chest and abdomen in 4 children′s hospitals in Shanghai are lower or close to the values given in the relevant national standards and the diagnostic reference levels in some European countries, with higher DLP values on some scanning sites. The CT scanning procedures for paediatric patients needs to be further optimized.

Monitoring on individual dose among radiation workers in medical institutions in Shanghai from 2015 to 2019 / 上海预防医学

ObjectiveTo determine the individual dose level and changing trend in the occupational external exposure of radiation workers in Shanghai， and provide scientific evidence for health risk assessment for radiation workers. MethodsIn the Occupational Health Management System for Radiation Workers of the National Health Commission-External Exposure Personal Monitoring and Management Subsystem， we retrieved the monitoring data of 38 077 external exposure individual dose of all medical radiation workers in Shanghai from 2015 to 2019. Using clustered sampling method， a total of 11 370 radiation workers in medical institutions （including tertiary， secondary， and primary hospitals） were selected in the study. Statistical analyses were conducted using SPSS 22.0. ResultsThe collective annual effective dose of 11 370 radiation workers was determined to be 4.340 person Sv， including 2.270 man·mSv in diagnostic radiology， 1.112 man·mSv in interventional radiology， and <0.5 man·mSv in other categories. The average annual effective dose was 0.382 mSv， which was 0.482 mSv in nuclear medicine， 0.431 mSv in radiotherapy， and <0.5 mSv in other categories. Moreover， the average annual effective dose of 6 workers （0.05%） was higher than 5 mSv， whereas that of 10 453 workers （92%） were less than 1 mSv； in addition， the annual dose of 911 workers （8.0%） was between 1‒5 mSv. All workers had average annual effctive dose lower than 20 mSv. The annual effective dose differed significantly by years （F=161.1， P<0.01）， by occupational groups （F=13.5， P<0.01）， and by hospital levels （F=264.5， P<0.01）. ConclusionThe average annual effective dose of radiation workers in medical institutions in Shanghai is lower than the national standard limit， suggesting proper and adequate radiation protection system and measures in medical institutions.

An investigation of radiation dose to adult subjects in computed tomography scanning in Shanghai, China / 中国辐射卫生

@#<b>Objective</b> To investigate dose parameters in computed tomography (CT) scanning of common body parts inall public medical institutions in Shanghai, China, and analyze the dose distribution of CT scanning among adult subjects in Shanghai, and to provide a basis for establishing the diagnostic reference levels of CT scanning in Shanghai. <b>Methods</b> We selected at least one medical institution with CT services each from all 16 districts of Shanghai. In each medical institution, a piece of CT equipment with qualified annual inspection was sampled to investigate the doses to subjects in head, chest, abdomen, and lumbar spine scanning. We collected the basic information of the subjects, CT scanning parameters, volumetric CT dose index (CTDI_vol), and dose length product (DLP). <b>Results</b> The scanning data of 1475 subjects were obtained. The 75th percentiles of the CTDI_vol of the head, chest, abdomen, and lumbar spine were 57 mGy, 11 mGy, 16 mGy, and 23 mGy, respectively. The 75th percentiles of the DLP were 862 mGy·cm, 361 mGy·cm, 593 mGy·cm, and 550 mGy·cm, respectively. <b>Conclusion</b> CTDI_vol and DLP differed significantly at different body parts, and also differed greatly at the same body parts. The DLP of men was slightly higher than that of women.