Comparison of foetus organ dose and cancer risks in sequential and helical modes in CT pelvimetry for pregnant patients: A Monte Carlo simulation study

Abstract

Author(s): Yassine Benameur*, Mohammed Najeh, Maroine Tahiri, Mounir Mkimel, Redouane El Baydaoui, Bouazza El Hariri, Mohammed Reda Mesradi, Abderaouf Hilali and Elmadani Saad

A pelvic CT scan may be recommended for a pregnant woman in the later stages of pregnancy if there is a possibility that the baby's head may be too large to fit through the pelvis during delivery. This examination assesses the size of the pelvis by measuring different bone diameters and provides information on the pelvis's morphology. Additionally, physicists and doctors frequently worry about ionizing radiation exposure might have a detrimental effect on the foetus. In this study, GATE Monte Carlo toolkit was used to model the SOMATOM EMOTION 16 CT scanner (Siemens Medical Solutions, Erlangen, Germany). The CTDI measurement was used to validate the simulated scanner model for energies 80 kV, 110 kV, and 130 kV. A voxelized phantom in the third trimester was scanned in sequential and helical modes. Organ foetal doses and mean doses were compared at 80 kV, in order to determine the foetal risks associated for each protocol's.

The mean foetal doses for sequential and helical mode are 0.74 mGy and 0.90 mGy, respectively. The risks of childhood cancer were 1 in 16,000 and 1 in 17,000 for sequential and helical modes respectively. The risks of hereditary disease were one in 220,000 and other in 270,000 for sequential and helical modes respectively. Although the cumulative dose to the foetus is thought to be less than 100 mGy, the foetal doses were considered acceptable.

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