Assessment of organ and tissue doses from computed tomography examination

Computed tomography examinations greatly contribute to the collective dose from diagnostic radiology. This is caused by increase in CT examination frequency and relatively high level of patient irradiation. Advances in design of CT scanners give better quality images but at the cost of increased patient exposure. Organ and tissue doses from CT examinations are usually assessed by Monte Carlo method and mathematical phantom. In this work anthropomorphic Alderson phantom and thermoluminescent detectors were used. Particular attention was paid to brain examination. In many CT installations the gantry is tilted during brain examination in order to limit eye lens exposure. M C method can not simulate this and as the result the eye lens and thyroid doses obtained by both methods differ considerably. (author)