Evaluation of a Model to Assess X-Ray Radiation Dose and Compare different Imaging Technologies in Congenital Heart Diseases

Objective: The effective radiation dose in diagnostic and interventional catheter investigations is difficult to compare in patients with congenital heart defects. This is caused by a high variability in patient size and weight, different angles, the use of monoplane or biplane equipment, the change in fluoroscopy only and image acquisition, and finally different frame rates used for image acquisition. Usually total fluoroscopy times and dose area products are used to provide some information and comparability, a standardized model however that enables a comparison between different X-ray devices is missing.

Method: We developed a phantom to enable a relatively simple comparability between different imaging technologies. First, we measured the chest diameters (AP and left-right) in 100 consecutive patients to characterize typical body composition phantoms. Then we analyzed typical diagnostic and interventional catheter procedures in patients with congenital heart defects regarding the fluoroscopy and image acquisition times and angles used. Thereafter we simulated these procedures in our models using different body shapes (i.e., chest diameters) and three weight classes (< 10 kg, 10–40 kg, > 40 kg). Finally we compared the Results with the Results obtained in 1000 consecutive patients, 500 with a state of the art Philips Xper system and 500 with the new Philips Allura Clarity system.

Result We analyzed typical catheter investigations for the following cardiac defects and procedures: PDA closure, ASD closure, balloon dilatation of a coarctation of the aorta, balloon dilatation of a valvular aortic stenosis, balloon dilatation of a pulmonary stenosis, diagnostic catheter pre bidirectional Glenn procedure and diagnostic catheter before Fontan completion. When comparing the Results of radiation (DAP) used obtained in real life with the data calculated by the phantom there was a relatively good comparison between patient data and the phantom, especially in models < 40 kg.

Conclusion: The model presented here allows a reasonable comparison of different X-ray imaging technologies in simulated procedures for patients with congenital heart defects. In addition by applying these Results training of medical staff as well as the evaluation of ALARA principles in different scenarios may be easily applicable.