Final answer:
The medical imaging modality that uses radioactive decay of radiopharmaceuticals is the Positron Emission Tomography (PET) scan, which is essential for imaging physiologic processes and diagnosing various diseases.
Step-by-step explanation:
The medical imaging technology that uses the radioactive decay of radiopharmaceuticals in the diagnosis and treatment of disease is Positron Emission Tomography (PET) scan. Distinct from other imaging modalities, a PET scan utilizes radioactive substances that are administered to the patient prior to the scan. These substances emit radiation that is detected by the scanner to create images of the body's physiologic activity, revealing areas with increased metabolism such as cancerous growths, due to their higher glucose consumption. Unlike CT scans and MRI, which provide static images, PET scans can show active blood flow and the functioning of various organs, thus being a powerful tool for diagnosing conditions including heart disease, cancer spread, infections, brain abnormalities, bone disease, and thyroid disease.