Radiographs are taken in the neonatal period most commonly to assist in the diagnosis and management of respiratory difficulties. Frequent accurate radiographic assessment is required and a knowledge of the radiation dose is necessary to justify such exposures. A survey of radiation doses to neonates from diagnostic radiography (chest and abdomen) has been carried out in the special care baby unit of the Royal Free Hospital. Entrance surface dose (ESD) was calculated from quality control measurements on the X-ray unit itself. Direct measurement of radiation doses was also performed using highly sensitive thermoluminescent dosemeters (TLDs) (LiF:Mg,Cu,P), calibrated and tested for consistency in sensitivity. ESD, as calculated from exposure parameters, was found to range from 28 microGy to 58 microGy, with a mean ESD per radiograph of 36+/-6 microGy averaged over 95 examinations. ESDs as derived from TLD crystals ranged from 18 microGy to 58 microGy for 30 radiographic examinations. The mean energy imparted, the mean whole body dose per radiograph and the mean effective dose were estimated to be 14+/-8 microJ, 10+/-4 microGy and 8+/-2 microSv, respectively. Assuming that neonates and fetuses are equally susceptible to carcinogenic effects of radiation, which involve an overestimation of risk, the radiation risk of childhood cancer from a single radiograph was estimated to be of the order (0.3-1.3) x 10(-6). Radiation doses compared favourably with the reference values of 80 microGy ESD published by the Commission of the European Communities in 1996, and 50 microGy published by the National Radiological Protection Board in 2000.

Naturally occurring isotopes of radon in indoor air are identified as the second leading cause of lung cancer after tobacco smoking. Winnipeg had the highest radon ((222)Rn) concentration among 18 Canadian cities surveyed in the past. There is great interest to know the current radon as well as thoron ((220)Rn) concentrations in Winnipeg homes. Therefore, radon-thoron discrimination detectors were deployed in 117 houses for a period of 3 months. The results confirmed that thoron is present at detectable levels in about half of the Winnipeg homes and radon remains significantly higher than the national average. In this study, radon concentrations ranged from 20 to 483 Bq m(-3) with a geometric mean of 112 Bq m(-3) and a geometric standard deviation of 2.07. It is estimated that 20% of Winnipeg homes could have radon concentrations above the Canadian indoor radon guideline of 200 Bq m(-3). This conclusion is similar to the previous estimation made 20 y ago. Thoron concentrations were below the detection limit in 60 homes. Among the homes with detectable thoron concentrations, the values varied from 5 to 297 Bq m(-3), the geometric mean and standard deviation were 21 Bq m(-3) and 2.53, respectively.

X‐ray regulations and room design methodology vary widely across Canada. The Canadian Organization of Medical Physicists (COMP) conducted a survey in 2016/2017 to provide a useful snapshot of existing variations in rules and methodologies for human patient medical imaging facilities. Some jurisdictions no longer have radiation safety regulatory requirements and COMP is concerned that lack of regulatory oversight might erode safe practices. Harmonized standards will facilitate oversight that will ensure continued attention is given to public safety and to control workplace exposure. COMP encourages all Canadian jurisdictions to adopt the dose limits and constraints outlined in Health Canada Safety Code 35 with the codicil that the design standards be updated to those outlined in NCRP 147 and BIR 2012.

A survey of entrance surface doses on 40 patients undergoing hysterosalpingography (HSG) has been undertaken. HSG is performed on women primarily of child-bearing age, with the dose to the gonads of these patients being of significant interest. Four lithium fluoride thermoluminescent dosimeters (TLDs) were attached to anatomical landmarks on the patient's skin to measure entrance surface doses. The results ranged from 0.5 mGy to 38.6 mGy with an average entrance surface dose of 13.3 mGy measured at the symphysis pubis. A correlation was observed between the entrance surface dose and imaging technique. Higher doses were measured when 24 x 30 cm film-screen radiography was used as opposed to fluoroscopy using 100 mm cut film for hard copy. Estimates of the organ dose to the ovaries were derived for both techniques yielding 2.8 mGy for 24 x 30 cm film-screen radiography and 1.7 mGy for 100 mm cut film.