In this section...
In the lab...
Types: Many different types of radioactive substances are used. Two radioactive materials that are commonly used are thallium and technetium. Each material has advantages. Thallium is less expensive and can detect lack of oxygen to an organ while a patient is at rest. Technetium produces clearer images and is faster.
Safety Precautions: A patient should avoid caffeine, abstain from alcohol and smoking a day before the imaging. No food should be eaten three hours before the test.
Orientation of Patient: The patient should lie down while the intravenous (IV) infusion is started. The radioactive tracer is injected into the bloodstream of the patient. Then, the patient is told to exercise on a treadmill or on a stationary bike. After the test, the patient lies down in order to let the gamma ray camera to detect the radioactivity. Images of the heart are obtained after the IV administration of the tracer, during the resting condition and again after the exercise. These images are then compared to assess if there is adequate perfusion of the heart during exercise.
Length of Scan: The entire examination (exercise, imaging, etc.) can take three hours. The gamma ray camera scans for approximately 20 minutes.
1896: Henri Becquerel was the first scientist to discover radiation.
Early 1900s: Georg von Hevesy used radioactive tracers to study the uptake of radioactive lead by plants. Georg also studied the movement of phosphorous in the human body by using radioactive tracers.
1929: Ernest Lawrence invented the cyclotron. The cyclotron was the first particle accelerator. With this invention, radioactive substances could be produced easily. These substances could be used as radioactive tracers for medical purposes.
1938: Glenn Seaborg along with Emilio Segre, discovered technetium-99. Technetium-99 is a common radioactive tracer used in nuclear medicine. Because of all the upcoming research at the time, a new organization was created. Marshall Brucer headed the Society of Nuclear Medicine.
1943: Georg won the Nobel Prize for the development of the radioactive tracer.
1958: Hal Anger invented the gamma camera. The gamma camera absorbs gamma radiation with a crystal. The absorption produces a flash of light, which is picked up by a computer that constructs an image from these flashes.