Hvor mye stråling attenuerer et ytre fettlag ved CT undersøkelser av pasienter med ulik BMI.

Project summary

The objective of this project is to calculate the extent to which subcutaneous fat attenuates the radiation dose delivered to tissues beneath the fat layer and to internal organs during CT examinations of the thorax–abdomen–pelvis, abdomen–pelvis, and thorax in patients with varying BMI values. The organs considered in this study are the heart, liver, intestines, and ovaries. Background: Due to automatic tube current modulation techniques, CT scanners automatically generate a higher radiation output when patients with elevated BMI undergo CT examinations compared to individuals with lower BMI. This means that the mAs product is adjusted according to patient size to maintain adequate image quality, and in some cases, kV values are also modulated. The key question is how much of this increased radiation exposure actually penetrates the patient’s subcutaneous fat layer, and how much is attenuated by the outer fat layer. By quantifying this, we can gain a clearer understanding of the true impact of increased radiation exposure on dose beneath the external fat layer, and consequently on organ doses to internal organs—potentially informing whether this represents an increased risk for future cancer development. Method: This will be a laboratory experiment conducted at the CT laboratory at Western Norway University of Applied Sciences (Høgskulen på Vestlandet). The CT scanner used will be a Siemens Somatom Perspective. Tissue equivalent additional plates corresponding to BMI values of 32 and 40 will be employed. These plates will be placed on an anthropomorphic phantom from Kyoto Kagaku. Dose measurements will be performed using a Piranha dosimeter from RTI. For internal organ dose estimation, a software program for virtual organ dose calculation is planned for use.