A pilot study is underway to inventory the existing useful methods of dose assessment in diagnostic radiology (DR). The actual entrance dose in standard conditions of different hospitals will be compared by thermoluminescent dosimetry (TLD) and some ionization chamber measurements. 2 diagnostic groups are to start the pilot study. The first is the lumbar hernia discalis diagnosis. A protocol for inclusion has been defined and a number of patients with sufficient technical details already selected.
TLD at radiation levels encountered in diagnostic radiology was tested and a reproducibility of +/- 2% was achieved. Discussions were started on the proceudure to be followed and the phantoms that will be used in computerized tomography (CT) and diagnostic radiology examinations and on the way to link film density and image quality to entrance dose.
The project will be carried out jointly by a Belgian and a Dutch research team. One part of the study will be devoted to the inventory of existing useful methods of dose assessment in diagnostic radiology; the actual entrance dose under standard conditions of different hospitals will be compared by thermoluminescent dosimetry and ionization chamber measurements. This dosimetry will be based on the work done by the cooperative group, Dose Assessment and Evaluation of Risk, coordinated by B.F. Wall (NRPB, UK). A few DGs will be selected for the pilot study : the medical teams will evaluate the existing work done in the field, define relevant DGs and test them in the participating hospitals. Once the procedure is established, a number of relevant patient files will be analyzed; an inventory will be made of the different radiological examinations performed before the diagnosis; the corresponding dose per examination will be calculated.
The physical and technical details and the medical parameters will together allow the received dose per DG for each participating hospital to be assessed. Finally, the applicability and validity of the total procedure will be tested by analyzing the different data sets per DG. The first question to be answered will be : is it possible to collect the relevant medical and technical data with this procedure for a sufficient number of patients? Secondly, which other elements are detectable within diagnostic procedures that are related to the doses per diagnosis, such as organization of health services and other? This study can contribute to elaborating recommendations or guidelines for the optimization of diagnostic radiology procedure to reduce the exposure of the European population to ionizing radiation and lead to a better use of national health resources.
Two contractors are involved in this project, and will share the tasks (physical and radiological).
The group of the Vrije Universiteit Brussels will be responsible for the coordination and the preparation of the progress reports, and the coordination of the work on DGs. A medical doctor of Akademische Ziekenhuis - VUB will contribute to the definition of relevant DGs. The work in Brussels will be performed with external consultancy by Dr. Lemort (Radiology) and Dr. Piron (Medical Physics) of the Bordet Institute and Dr. Perlmutter of Reine Fabiola Hospital's Radiology Department in Brussels.
The group of the Akademische Ziekenhuis Nijmegen will coordinate the assessment of dose per examination by thermoluminescent dosemeters. This team will use its equipment and calculation programmes for the technical analysis. Seven physicists of the Department of Radiology, Nijmegen, will collaborate. The NRPB protocol will be analyzed on applicability in this project, in cooperation with the NRPB.