|
KMID : 0857020060210010256
|
|
Kosin Medical Journal
2006 Volume.21 No. 1 p.256 ~ p.259
|
|
|
Thyroid Dose During Thoracic Irradiation in Lung Cancer
|
|
Kim Soo-Kil
|
|
|
Abstract
|
|
|
Background: To determine the radiation dose received to the thyroid gland as a result of thoracic irradiation in the patients with lung cancers, and the factors influencing that dose.
Methods: The dose to the thyroid resulting from the simulated irradiation of the chest of an adult anthropomorphic(humanoid) phantom with 6MV X-rays was measured using thermoluminescent dosimeters (TLDs). The dependence of dose on the distance of the x-ray source was measured. The effects of a bolus was also determined.
Results: Using shielded field, the thyroid region received 13-16% of the prescribed dose on the surface of phantom and 32-33% in phantom for 6MV X-rays. The dose increased as the measurement point on skin closer to the x-ray source due to tissue scatter. Placement of a bolus around the neck increase the thyroid dose by 30% compared to the thyroid dose without bolus.
Conclusion: For prophylactic irradiatiion doses of 2000 cGy in the adult phantom, the dose to the thyroid was about 300 cGy(15%). As the thyroid is very sensitive to radiation and the dose-response curve for thyroid tumor induction is linear, attempts to shield the thyroid during prophylactic irradiation are mandatory. The use of shielding block and bolus were important factors in determining thyroid dose.
|
|
|
KEYWORD
|
|
|
prophylactic irradiation, TLD, humanoid phantom, thyroid dose, bolus
|
|
|
FullTexts / Linksout information
|
|
|
|
|
Listed journal information
|
|
|