Which of the following is NOT considered a diagnostic test for cancer?

Scintigraphy is primarily used in nuclear medicine to visualize functionality and physiological processes within the body, rather than directly diagnosing cancer itself. It involves the use of radioactive substances to produce images of areas of the body where cancer may or may not be present. While scintigraphy can indicate abnormalities or areas of concern, it does not provide definitive information about the presence of cancer tissue itself.

In contrast, a biopsy involves taking a tissue sample for microscopic examination, which is crucial for a definitive cancer diagnosis. Lab tests for tumor markers measure specific substances in the blood or tissues that can indicate the presence of cancer. Magnetic Resonance Imaging (MRI) provides detailed images of soft tissues and can reveal tumor size, location, and characteristics, aiding in the assessment and diagnosis of cancer.

Thus, the identification of scintigraphy as not being a diagnostic test for cancer reflects its role more as a complementary imaging technique rather than a definitive diagnostic procedure.