Dose reduction to radiosensitive tissues in CT. Do commercially available shields meet the users' needs?
OBJECTIVE
To assess the effectiveness and economy of routinely using commercially available in-plane bismuth shielding during CT scanning of the chest and brain.


METHODS
Forty patients were scanned with thermoluminescent dosemeters (TLDs) in situ to measure the radiation dose to the thyroid and eye during CT scanning of the brain and chest. Half of the patients had the "AttenuRad" shield in place during scanning.


RESULTS
Use of the shielding reduced the mean dose to the eye from 6.0 +/- 0.3 mGy to 4.9 mGy +/- 0.2 mGy and the thyroid dose from 16.4 mGy +/- 1.2 mGy to 7.1 mGy +/- 0.5 mGy.


CONCLUSIONS
Use of the thyroid shield is recommended for all CT scanning of the chest. The eye shield does not produce as marked a reduction in radiation dose to the lens of the eye, when an angled gantry is used, since the eyes are not in the primary beam. Use of the eyeshield is justifiable where irradiation of the orbit is unavoidable, although whether artifacts would be a problem if the shield was used in this way was not assessed.
McLaughlin
D J
DJ
Altnagelvin Area Hospital, Londonderry, Northern Ireland BT47 6SB, UK.
Mooney
R B
RB
D004307:Dose-Response Relationship, Radiation; D004867:Equipment Design; D006801:Humans; D007908:Lens, Crystalline / Q000528:radiation effects*; D011482:Protective Devices / Q000592:standards; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000517:prevention & control*; D011835:Radiation Protection / Q000295:instrumentation*; D013819:Thermoluminescent Dosimetry; D013961:Thyroid Gland / Q000528:radiation effects*