Diagnostic and Interventional Radiology

Diagnostic and interventional radiology (DIR) constitutes a wide scope of medical imaging modalities: general radiography, mammography, diagnostic fluoroscopy, interventional radiology, interventional cardiology, computed tomography (CT), magnetic resonance imaging (MRI), ultrasound imaging (USI) and dental x-ray imaging.

Imaging is best described as a chained sequence of processes, starting with the x-ray detection system, followed by any image processing. The final link in the chain culminates with the display of the image calibrated to the visual response of the human optical system.

Medical physicists in this area play a role in each link of this chain as part of a quality assurance programme. The medical physicist is responsible for ensuring the precise and consistent production of x-rays across multiple systems and time; is responsible for the definition and assessment of various image quality parameters. Radiology display panels, whilst not being image acquisition devices, also form part of the physicist’s quality assurance programme, to ensure greyscale values are properly calibrated.

DIR medical physicists are responsible for the establishment and application of patient dose audits. These are used to determine typical patient doses for standard examinations and are useful metrics to evaluate performance, while also being a starting point for the optimisation of systems and clinical protocols.

DIR medical physicists work closely with radiologists and radiographers as well as with biomedical engineers to develop specifications and to conduct acceptance testing and commission new systems.

Incidents, whilst an unlikely occurrence, do from time to time occur. The medical physicist is informed of any cases to estimate the inadvertently administered radiation dose using state of the art computer simulations to obtain an estimate that is as accurate as possible. The events leading to the incident are investigated and in liaison with the radiation protection expert, steps are taken to mitigate similar incidents from occuring in future.