Implementation of a comprehensive set of optimised CBCT protocols and validation through imaging quality and dose audit.

OBJECTIVES: Cone-beam computed tomography (CBCT) for radiotherapy treatment verification has increased in frequency; therefore, it is crucial to optimise image quality and radiation dose to patients. The aim of this study was to implement optimised CBCT protocols for the Varian TrueBeams for most tumour sites in adult patients. METHODS: A combination of patient size-specific CBCT protocols from the literature and developed in-house was used. Scans taken before and after optimisation were compared by senior radiographers and physicists to evaluate how changes affected image quality and clinical usability for online image registration. The change in dose for each new CBCT protocol was compared to the Varian default. A clinical audit was performed following implementation to evaluate the changes in imaging dose for all patients receiving a CBCT during that period. RESULTS: Ten CBCT protocols were introduced including head and neck and patient-size-specific thorax and pelvis/abdomen protocols. Scans from 102 patients with images before and after optimisation were assessed, none of the scans showed image quality changes compromising clinical usability and for some image quality was improved. Between November 2020 and June 2021, 1185 patients had CBCTs using the new protocols. The imaging dose was reduced for 52% of patients, remained the same for 37% and increased for 12%. CONCLUSIONS: This study showed that substantial dose reductions and image quality improvements can be achieved with simple changes in the default settings of the Varian TrueBeam CBCT without affecting the radiographers' confidence in online image registration. ADVANCES IN KNOWLEDGE: This study represents a comprehensive assessment and optimisation of CBCT protocols for most sites, validated on a large cohort of patients.

Occupational radiation exposure in doctors: an analysis of exposure rates over 25 years.

OBJECTIVES: Healthcare professionals' occupational exposure to ionising radiation may be increasing due to increasing use of imaging and image-guided intervention. This study aims to assess the occupational exposure of doctors over a 25-year period at an NHS teaching hospital. METHODS: Dosemeter measurements were collected prospectively from 1995 to 2019. Two retrospective analyses were performed over time (first including all measurements, second excluding "zero-dose" measurements), and by speciality. Group comparisons were undertaken using multilevel linear regression; a p-value <0.05 was deemed significant. RESULTS: 8,892 measurements (3,983 body, 1,514 collar, 649 eye, 2,846 hand), of which 3,350 were non-zero measurements (1,541 body, 883 collar, 155 eye, 771 hand), were included. Whole dataset analysis found a significant decrease in exposure for radiologists and cardiologists, as measured by body, hand and collar dosemeters over the last 25 years (p < 0.01 for all). The non-zero readings reflect the whole cohort analysis except in the case of eye dosemeters, which showed a significant decrease in exposure for cardiologists (p < 0.01), but a significant increase for radiologists and surgeons/anaesthetists (p < 0.01 for both). CONCLUSIONS: Whilst ionising radiation remains an occupational risk for doctors, the overall decreasing trend in occupational exposure is reassuring. However, a significant rise in eye dose for radiologists, surgeons and anaesthetists is concerning, and close monitoring is required to prevent future issues. ADVANCES IN KNOWLEDGE: This paper is one of few evaluating the occupational radiation exposure to doctors over a 25-year period, showing that although most dosemeter measurements reflect decreasing exposure, the increase in eye exposure warrants caution.

Radiation Safety Culture in the UK Medical Sector: A Top to Bottom Strategy.

UK professional bodies have established a number of sectorial working parties to provide guidance on the improvement of radiation safety (RS) culture in the workplace. The medical sector provides unique challenges in this regard, and the remit of the medical group was to review the current state of RS culture and to develop a framework for improvement. The review of current RS culture was based on measurable indicators, including data from regulatory inspections, personal monitoring data and incident data. An online survey to capture the RS-related views and experience of hospital staff at all levels was carried out, and the responses provided a wealth of information on RS awareness and implementation across the country. The framework for improving RS culture includes both 'top-down' initiatives to engage management and regulators, and 'bottom-up' initiatives relating to engagement and training of different staff groups. A 'Ten-point Assessment' on what constitutes a good approach to medical RS culture has been proposed, which provides a tool for management to assess RS culture in the workplace and has potential use in regulatory inspections in the UK.

Sociodemographic factors and utilization of eye care services: is there an association with patients presenting to a tertiary referral hospital in acute angle-closure?

BACKGROUND: The aim of this study is to examine the relationship between sociodemographic factors and utilization of eye care services in patients presenting in acute angle-closure (AAC). DESIGN: A hospital-based retrospective, case-control study. PARTICIPANTS: Fifty-five patients consecutively presenting to the emergency department of the Royal Victorian Eye and Ear Hospital with AAC (cases), and 43 patients consecutively referred to the outpatient department for prophylactic laser peripheral iridotomy (controls) over a 3-year period. METHODS: Standardized telephone questionnaires. MAIN OUTCOME MEASURES: Comparisons were made for sociodemographic factors, utilization of eye care services and provision of information on glaucoma and premonitory symptoms of AAC. RESULTS: No significant differences across a range of socioeconomic and demographic factors were found. Fewer cases reported having attended an eye care professional ever (P = 0.02), or in the 12 months preceding their acute hospital attendance (P = 0.002), and had less awareness of angle closure glaucoma (P = 0.001). Logistic regression modelling demonstrated premonitory symptoms of AAC (odds ratio 3.96, [95% confidence interval 1.52-10.32], P < 0.001) and a period of greater than 12 months since the last eye examination (odds ratio 3.89, [95% confidence interval 1.64-9.21]) were significantly associated with the risk of AAC. CONCLUSIONS: No significant differences in socioeconomic or demographic parameters between cases and controls were identified. Control subjects had a history of more frequent and recent access to eye care services than cases. The finding that more than one-third of patients presenting with AAC had consulted an eye care provider in the preceding year suggests that a significant proportion of individuals at risk of AAC remain undetected.