Assessing the Impact of Patient Lung Volume Variations on Absorbed Lung Doses at Y-90 Therapy Using GATE Toolkit

In Y-90 treatment, the dose values received by the target organ and tumour, as well as the dose values received by critical organs, have a significant impact on the treatment planning process and ultimately determine the amount of activity to be used in the treatment. To this end, 10 different phantoms containing lung volumes ranging from small to large for the same activity values in the liver have been designed to evaluate the risk of lung toxicity in Y-90 treatment. Utilizing the GATE toolkit, a 10 mm diameter tumour volume containing 10 mCi activity has been positioned within the liver geometry, and the absorbed dose values have been calculated in lung volumes ranging from 3,103E+06 to 4,727E+06 mm³ in the right lung and from 2,021E+06 to 3,080E+06 mm³ in the left lung. Absorbed dose values have been calculated as maximum 3,046E-071,607E-08 Gy/s, minimum 1,868E-071,177E-08 Gy/s in left lung, maximum 8,772E-086,905E-09 Gy/s, minimum 5,164E-084,963E-09 Gy/s in right lung and maximum 3,923E-071,14852E-08 Gy/s , minimum 2,384E-078,36556E-09 Gy/s in total lung. The results of this study may indicate that the absorbed dose value in the lung increases with an increase in lung volume. A comparison has been made with existing studies in the literature.