I recently had the above scan for possible hyperparathyroidism. There were no results--nothing lit up. The radiologist wanted to know if I took medicines containing iodine or had had previous neck surgery. The answer to both questions is NO. My doctor said that it was extremely rare for nothing to light up on the scan but "not to worry about it." This was not very reassuring. What could cause a result like mine?
A Sestamibi scan is a nuclear medicine scan, of which I know very little about. Here's what I DO know:
In nuclear medicine, a radioactive substance is injected into your bloodstream. Over time, the radioactive material concentrates in the organs and bones of your body. A nuclear medicine scanner then detects the radioactivity coming out of your body and creates an image.
The doctor is usually looking for an area of concentrated radioactivity, i.e. an area that's "lit up". If nothing lights up on your scan, that's usually good news.
I think the reason he asked if you'd had neck surgery or took medications with iodine is probably due to a lack of signal in the neck. Medication with iodine or surgical alterations might affect the uptake of radioactive isotope by the thyroid.
If your doctor said it's nothing to worry about, then don't worry. If you question his advice, you could always get a second opinion.
Hope this helps,
Santa Barbara Extremity MRI