Risks of Thallium in Stress Testing

Posted By  CCF Cardio MD-SGM on March 23, 1998 at 09:51:53:

In Reply to: Risks of Thallium  in Stress Testing posted by Murray Rose on March 15, 1998 at 23:47:09:

: Dear Sirs:
       What are the risks of thallium injections in stress testing versus
  standard stress testing? I know the former gives better results. However
  doesn't introducing radioactive materials into the body increase the
  incidence of cancer, especially if done yearly. I had an angioplasty
  of the RCA, 3 years ago,am taking suitable medications,exercise & diet
  and have had no symptoms since. Thank you.
                                            ***@****

[CCF Cardio MD-SGM]

Dear Mr. Rose,
Nuclear medicine physicians in conjunction with federal regulators have determined safe levels of exposure to radioactivity.  You are correct that thallium, a radio- pharmaceutical used for perfusion imaging studies of the heart, carries some risk.  However, the risk to a patient who undergoes one or several studies a year is negligible.   In determining risk from radiation exposure,  federal standards have established maximum levels of cumulative exposure above which the risk is considered to be excessive.   Many sources contribute to ones radiation exposure, including natural background radiation, standard X-rays, other diagnostic studies such as CT scans, and radiopharmaceuticals such as Thallium and others.  
I'm happy to reassure you that an intermittent thallium study will not increase your risk of cancer appreciably.    Such testing will fall well within maximum exposure guidelines, and is thus considered safe.  Most importantly, apart from the exposure issue we've discussed, you'll need to review the medical indications for performing such a study.  This should be discussed with your physician.
I hope this has been helpful.  Information in the Heart Forum is for general purposes only.  Specific diagnoses and therapies can only be provided by your physician.