Final answer:
Nuclear Medicine is the technique where radioactive materials are used to gather information about the function of organs and tissues. It employs radiopharmaceuticals that are absorbed differently by different types of tissues, which is beneficial in diagnosing various diseases such as heart disease and cancer.
Step-by-step explanation:
The imaging method in which radioactive materials are injected into the body or ingested to provide information about the function of organs and tissues is known as Nuclear Medicine.
In nuclear medicine, radiopharmaceuticals are traced in the body to reveal metabolic and physiological functions in tissues. This technique can be used to assess various conditions, including cardiovascular diseases with thallium scans for the coronary arteries, thyroid function using iodine, and cancer imaging with isotopes like Gallium-67. Unlike other imaging techniques such as MRI that use magnetic fields or ultrasound which uses sound waves, nuclear medicine involves the administration of radioactive substances (radiopharmaceuticals) to diagnose and treat diseases.
For instance, when iodine is used to image the thyroid, the most active thyroid cells—including cancerous cells—absorb more iodine and therefore emit more radiation. Similarly, Gallium-67 is accumulated in areas of rapid cell growth and is therefore useful in cancer imaging.