Evaluation of the occupational X-rays dose of the medical staff in a cardiac catheterization laboratory using an acrylic phantom and semiconductor dosimeter.

OBJECTIVE: The occupational X-rays doses of medical staff in a cardiac catheterization laboratory were evaluated.

METHODS: Four customized acrylic phantoms were used to simulate a patient, medical doctor, assistant, and radiologist to evaluate the in-situ X-rays exposure dose using semiconductor dosimeters. The exposure dose was measured under three scenarios that were preset to imply: no shielding, moderate shielding and complete shielding for the medical staff in the laboratory. The doses were applied by changing the dose area product (DAP) from 11,000 to 500,000mGy·cm(2) in 14 increments.

RESULTS: The estimated annual occupational doses for doctors, assistants and radiologists in scenarios I, II, and III were: I) 35.03, 7.78, 1.95; II) 1.95, 0.78, 0.06; and III) 0.19, 0.10, 0.05cSv, respectively. The derived linear regression line of the exposure dose with respect to the DAP were extrapolated to obtain the minimum detectable level (MDL) of DAP for triggering the staff dosimeters. Accordingly, the minimum annual dose was estimated as 0.05cSv. Additional shielding provided measurable protection to the staff. The protective clothing used in scenarios II and III can reduce the original dose from scenario I to ∼3% (scenario II) and ∼0.5% (scenario III). The annual occupational dose also changed with the various X-rays energy settings. The annual dose increased to 126% when the preset X-rays energy was changed from 70 to 100kVp.

CONCLUSION: The semiconductor dosimeter proved to be an adequate tool for measuring low doses and low dose rates under these circumstances. The dose can be reduce of I) 35.03, 7.78, 1.95; to II) 1.95, 0.78, 0.06 (∼3%); or III) 0.19, 0.10, 0.05 (∼0.5%)cSv, respectively according to different protective scenarios.