Effectiveness of protective patient equipment for CT: an anthropomorphic phantom study

Protective patient equipment for CT examinations is not routinely provided. The aim of this study was to determine whether, and if so what, specific protective equipment is beneficial during CT scans. The absorbed organ doses and the effective doses for thorax, abdomen/pelvis and brain CT investigation with and without the use of protective patient equipment have been determined and compared. All measurements were carried out on modern multislice CT scanner using an anthropomorphic phantom and thermoluminescence dosemeters. The measurements show that protective equipment reduces the dose within the scattered beam area. The highest organ dose reduction was found in organs that protrude from the trunk like the testes or the female breasts that can largely be covered by the protective equipment. The most reduction of the effective dose was found in the male abdomen/pelvis examination (0.32 mSv), followed by the brain (0.11 mSv) and the thorax (0.06 mSv). It is concluded that the use of protective equipment can reduce the applied dose to the patient.

Radiation exposure of patients who undergo CT of the trunk

PURPOSE: To determine the radiation dose delivered to organs during standard computed tomographic (CT) examination of the trunk. MATERIALS AND METHODS: In vivo locations and sizes of specific body organs were determined from CT images of patients who underwent examinations. The corresponding CT investigations were then simulated on an anthropomorphic phantom. The resulting doses were measured at 70 different sites inside the phantom by using thermoluminescent dosimeters. On the basis of measurements of free-in-air air kerma at the rotation axis of the CT gantry, conversion factors were calculated so that measurements could be used with different models of CT equipment. RESULTS: Starting from the dose values recorded, the mean organ doses were determined for 21 organs. The skin received 22-36 mGy; the lungs, less than 1-18 mGy; the kidneys, 7-24 mGy; and the ovaries, less than 1-19 mGy, depending on the type of CT examination performed. CONCLUSION: These values are high compared with other x-ray examinations and should be minimized as much as possible. The number of tomographic sections obtained should be kept as low as possible according to diagnostic need.

[Radiation protection in diagnostic radiology]

For every diagnostical X-ray radiation exposure the applied dose has to be limited to the smallest possible value. Within the scope of a general Swiss survey it has been found that in the various medical practices and hospitals the applied doses varied quite strongly. The main reasons leading to an overdose were the operating conditions of the X-ray and film processing equipment, the film and foil materials and improper filming techniques. The applied single dose served as a measure for the radiation protection assessment of diagnostical X-ray exposures. To prevent this in the future, individual patients who are exposed to unnecessary radiation loads should be regularly checked in quality-ensuring tests.