Parathyroid scanning is a nuclear study performed to assist in diagnosing tumors or hyperplasia of the glands. The main function of the glands is to synthesize, secrete, and store parathyroid hormone, which regulates the level of calcium and phosphorus in the blood. Change in these levels indicates hyperparathyroidism. The radionuclide 201Tl as thallium chloride Tl 201 is administered IV, and scanning is performed in 20 minutes. This is followed by the administration of 99mTc as technetium Tc 99m pertechnetate, and additional scanning is performed. Computer subtraction of images is performed to complete the study and determine the amount of the radionuclide concentrated in the parathyroid glands as opposed to the thyroid gland (thallium chloride Tl 201 is taken up by normal thyroid tissue).⁴¹

• Normal size, position, number, weight, and function of the parathyroid glands with normal uptake of the radionuclide in the parathyroid and thyroid glands, no hyperplasia or adenoma of the parathyroids

• Inability of client to remain still during the procedure
• Recent intake of iodine-containing foods or medications, or recent tests and procedures using iodinated contrast media

• Differentiating between parathyroid hyperplasia and adenoma revealed by a larger sized gland in adenoma
• Identifying and locating ectopic glands to prevent missing a tumor during surgical excision

Contraindications

• Pregnancy, unless the benefits of performing the procedure greatly outweigh the risks to the fetus

Nursing Care Before the Procedure

Client teaching and physical preparation are the same as for any thyroid nuclear scan study (see section under "Brain Scanning" and preceding "Thyroid Scanning" section).

The client is placed on the examining table in a supine position with the neck slightly hyperextended. The client is requested to remain still during the scanning, and thallium chloride Tl 201 is administered IV. Scanning is performed in 5 to 30 minutes for mediastinal and neck views. Technetium Tc 99m pertechnetate is then injected, and scanning is performed for the same views. Computer subtraction of images is performed by the subtraction of the 99mTc imaged in the thyroid from the 201Tl uptake in the parathyroid glands.

Nursing Care After the Procedure

Care and assessment after the procedure are the same as for any nuclear scan study (see section under "Brain Scanning").