Diagnostic heart scans such as CT angiograms can lead to cancer, kidney damage, false positives and overtreatment -- and they don't even improve outcomes in healthy patients.

If that's not enough to scare you away from any doc who orders up a scan "just in case," consider this: These tests can also cause lasting or even permanent damage to the very gland that helps control everything from weight and blood pressure to heart health and sexual function.

The scans use iodide dye, and not just a little bit. They use hundreds of times the daily limit for iodide -- and the reason there's a limit at all is that iodide can knock your thyroid gland down for the count.

Now, a new study of 1,800 Boston-area heart patients lays out the risk in black and white: Patients with thyroid problems are up to three times more likely to have had a scan involving iodide dye than those without.

Out in the real world, that adds up to one extra patient battling an overactive thyroid (hyperthyroidism) for every 33 given the dye, and one extra patient with an underactive one (hypothyroidism) for every 36 given the dye.

That's nearly six out of every 100 patients with one form of thyroid problem or another, according to the study in the Archives of Internal Medicine.

That's a risk you don't have to face -- because there are much better, safer and far more accurate ways to check on your cardiovascular health.

One leading naturopath, Dr. Mark Stengler, recommends a simple blood test to measure levels of an enzyme that shows up whenever your arteries are battling the ravages of inflammation.

The enzyme is called lipoprotein-associated phospholipase A2, or Lp-PLA2, but don't worry about trying to memorize any of that. The only name you need to remember is PLAC, which is the test that checks for those levels -- and you don't even have to "go alternative" to get it.

The PLAC test is actually approved by the FDA as a means of testing both heart and stroke risk -- but you might have to point that out to your own doc if he still wants to pump you full of dye and blast you with radiation.

If your Lp-PLA2 levels top 235 ng/mL, you're at risk. Some docs will tell you to take statins, but who wants to face all the risks of those meds? Dr. Stengler offers a much better solution: antioxidant vitamins and a sensible Mediterranean-style diet.

Sounds like a good plan to me even if you're not facing heart risk.