Röntgenuntersuchungen von Frühgeborenen in modernen Inkubatoren : Eine dosimetrische und qualitative Evaluation

Advancing therapeutic measurements in current neonatal intensive care units have pushed the limits of premature birth weight to less than 1500g and 22 weeks of gestation. Due to their immature immune system and organs these patients have a high susceptibility to infections and need an intensive care treatment. This includes frequent X-ray-imaging. As each manipulation provokes unfavorable distress, modern incubators have a X-ray-tray for the imaging plate underneath the matress to faciliate the handling. From a strictly radiological point of view this situation has some disadvantages due to the layers in the X-ray-beam which influence the dose and imaging quality negatively. This work investigates the technical and dosimetric circumstances in X-ray-imaging in modern incubators. To assess these information first dosimetric experiments with a dummy were performed in four different types of incubators. In a second step the dimensions of the incubators were transmitted into a virtual 3D-model and a Monte-Carlo-simulation was performed. The influence of the different layers concerning the imaging quality, defined as the signal-to-noise-ratio, were evaluated and the dosimetric aspects were furthermore explored. The results showed, that posing the imaging plate in the build-in tray causes an average decrease of 49% in the signal-to-noise-ratio compared to the position directly underneath the neonate, mainly influenced by the absorption of the mattress. The use of the tray should therefore be put into question according to the physical constitution of the patients.