Does the lead apron and collar always reduce radiation dose?

Area of Science:

• Medical Physics
• Radiological Protection
• Radiation Dosimetry

Background:

• Personal lead shielding devices are routinely used in medical imaging to minimize radiation exposure.
• The potential for these devices to inadvertently increase radiation absorption, particularly to sensitive organs like the pituitary gland, has not been thoroughly investigated.

Purpose of the Study:

• To determine if the use of lead aprons and thyroid collars increases the absorbed radiation dose to the pituitary gland.
• To investigate the impact of standard lead shielding on pituitary gland dosimetry in radiological procedures.

Main Methods:

• Thermoluminescent dosimeters (TLDs) were calibrated and used to measure absorbed dose in the pituitary region of a Rando-Alderson phantom.
• Experiments were conducted with and without a 0.25 mm lead equivalent apron and thyroid collar, simulating clinical transpharyngeal exposures.
• Statistical analysis compared pituitary dose between shielded and unshielded conditions, with results replicated using a different dosimetry system and a male phantom.

Main Results:

• A statistically significant increase (P < 0.05) in absorbed dose to the pituitary gland was observed when lead shielding (apron and collar) was used.
• Both female and male phantoms demonstrated significantly higher pituitary region doses under shielded conditions compared to unshielded conditions.
• These findings were consistent across different phantom types and dosimetry systems.

Conclusions:

• The use of lead aprons and thyroid collars can significantly increase, rather than decrease, the radiation dose absorbed by the pituitary gland.
• Current practices of personal lead shielding may lead to unintended dose escalation to the pituitary gland.
• Further research is warranted to understand the mechanisms behind this phenomenon and to revise radiation protection guidelines accordingly.