COMPUTATIONAL MODELS EMPLOYED FOR DOSE ASSESSMENT IN DIAGNOSTIC-RADIOLOGY

Optimisation in diagnostic radiology means achieving a reasonable comp romise between high image quality and low dose to the patient. A conve nient method to evaluate the influence of an examination technique on patient dose is the calculation of organ doses using radiation transpo rt codes together with computational human models. A brief history of the computational models is given and the differences between mathemat ical and tomographic models are described. Dose calculations performed in nuclear medicine and diagnostic radiology are briefly summarised; the limitations of calculated organ doses with respect to accuracy and applicability to individual situations are discussed. Finally, the po ssible use of dose calculations for optimisation procedures in diagnos tic radiology, due to quantification of the effects of measures aimed at dose reduction or limitation on single organ doses, is illustrated.