During a parathyroid scan, a radiologist or technologist passes a handheld ultrasonic device over the neck to produce an image of the parathyroid glands, as described by WebMD. The test takes about 30 minutes to complete.
In preparation for a parathyroid scan, the patient needs to undress above the waist and remove jewelry from the head and neck, according to WebMD. The patient then lies on his back on a high table with a pillow under the shoulders to stretch out the neck. The radiologist spreads gel on the neck to facilitate the passage of the sound waves through the patient's body. The radiologist may also place a small bag of water or a gelatin sponge on the neck to improve the transmission further. He then passes the ultrasound transducer over the neck to create a picture of the parathyroid glands and surrounding tissue. The patient may need to turn the head during the test to move the jawbone out of the way.
A parathyroid scan is not painful and does not impede breathing, although some patients find it uncomfortable to keep the neck extended, according to WebMD. The gel applied at the beginning of the test can feel cold. A parathyroid scan has a very low risk of side effects, and it is safe for use during pregnancy.