National Entry Level Dental Assistant (NELDA) 1 Practice Test

In dental radiography, some tissues are much more radiosensitive than others, especially those with rapid cell turnover. The tissue that sits in the path of the primary X-ray beam and is highly radiosensitive is the thyroid gland in the neck. Because the beam can pass through that region during head-and-tooth imaging, the thyroid is at higher risk of receiving a substantial dose unless shielding is used. The cornea is not typically within the primary beam in routine dental views, and bone is relatively less radiosensitive compared with soft tissues like the thyroid. So the thyroid gland is the tissue most at risk in this context, which is why shielding there is emphasized.