Patient and staff dosimetry in diagnostic and interventional radiology

This work evaluated radiation doses for a selection of x-ray examinations in diagnostic and interventional radiology (IR) that offer unusual challenges to radiation protection. For IR applications, doses were evaluated during endoscopic retrograde cholangiopancreatography (ERCP) and during procedures that applied CT Fluoroscopy (CTF). Results demonstrated the risk for high patient skin doses and identified that the eye of the interventionalist is the organ at most risk. A drastic dose reduction in CTF was achieved due the combination of utilising a low tube current technique in combination with intermittent fluoroscopy and a system that interrupts x-ray tube exposure when it travels above the patient. In the diagnostic radiology field, a multi-centre study was performed of doses to children from CT scans, and an assessment was performed of dose and risk from prospective health screening programmes with CT. Results demonstrated that children may be exposed to unnecessarily high radiation doses when scan parameters are not optimised. Excess mortality risk factors are demonstrated for potential health screening programmes with CT. They indicate that dose should be considered as a fundamental parameter for outlining a screening strategy. Screening with CT could be justified for a targeted population with an elevated predisposed mortality risk. Patient dose optimisation also involves quality assurance of the total imaging chain in radiology. We identified physical properties of medical display devices that influenced diagnostic performance and suggest a quality assurance programme to detect non-optimised systems.