Can thyroid cancer be detected with a blood test?
If the thyroid blood tests are normal, radioactive iodine scans are seldom used today in the evaluation of thyroid nodules. Radioactive iodine scans of the neck will document the location and general size of the isotope-concentrating thyroid but not as precisely as will an ultrasound. The portion of the gland which does not concentrate the radioisotope will not be visualized. It does provide a measure of the gland’s ability to “pick-up” or concentrate the radioactive isotope, a gross measure of thyroid function. Most thyroid tumors, benign and malignant, will not concentrate the isotope but, on the contrary, a small portion of tumors that do so may be malignant. Thus, the radioactive isotope scan provides little help in distinguishing between benign and malignant tumors.
