About Nuclear Medicine
Video, courtesy Loma Linda University Health
What is Nuclear Medicine?
Nuclear Medicine is an advanced imaging modality that uses radiopharmaceuticals to acquire images of organs of the body. Nuclear Medicine procedures assess how the organs work and can play an important role in early diagnosis. While X-rays, CT, MRI and ultrasound assess structure, nuclear medicine focuses on function. Unlike X-rays and CT's, the nuclear gamma camera does not emit radiation. Nuclear medicine procedures can be performed on virtually every organ of the body. One of the most common uses of nuclear medicine is in assessing cardiac disease. Other common uses are in diagnosis of pulmonary embolism for patients who are allergic to intravenous CT contrast, assessment of gall bladder disease, bone metastases, infection, gastroparesis and thyroid disease.
How do I prepare for a nuclear medicine procedure?
As a general rule of thumb, procedures that involve the stomach or gastrointestinal system require that you do not eat or drink anything after midnight prior to the day of the procedure. Nuclear stress tests also require that you do not eat or drink anything at least 6 hours prior to procedure. Depending on the specific method of stress, you may also be required to be off some blood pressure medications. Be sure to speak with your physician to receive instructions regarding medications.
Nuclear studies are generally not encouraged for pregnant patients, unless absolutely necessary. The radiopharmaceutical dose is typically reduced to minimize exposure to the fetus. If you are breast-feeding, let the technologist know prior to starting the procedure.
What happens during a nuclear medicine procedure?
A trace amount of radioactive material will be injected in the vein. It then travels through the bloodstream to the organ that needs to be imaged. For thyroid and gastric exams, the radiopharmaceutical is administered orally. The tracers emit a pattern of rays representing the organ size, shape and function. The rays are detected by a gamma camera, producing an image on a computer screen. The images are transferred to a work station where the technologist uses processing software to convert them to a format presented to the radiologist for review and interpretation.
Most nuclear medicine studies are performed with a radioisotope called Technetium which has a half life of 6hrs. This means that half the administered dose is out of the body in 6 hours and almost all is gone in 36 to 48 hours. When other higher energy isotopes are used, you will be given relevant special instructions that apply to those specific radioisotopes.
To get the best image quality, it is very important to stay still while images are being acquired. Nuclear Medicine studies are motion-sensitive and even slight motion could obscure the images and result in poor quality images and inaccurate diagnosis. Let the technologist know how he/she can help you get in a comfortable position prior to starting the scan. We want to do everything we can to ensure accurate diagnosis.
Links to instructions for Nuclear Medicine Procedures
Molecular breast imaging (MBI)
Renal flow & function with Lasix
Renal flow & function without Lasix Renal hypertension assessment with Captopril Renal morphology with DMSA
WBC Ceretec or Indium WBC Scan
Salivary gland scan (Parotid gland imaging)
Thyroid uptake & scan
Hepatobiliary (Gallbladder) or HIDA Scan
Gastric Emptying Scan
Liver and Spleen Scan Liver SPECT Scan (hemangioma) Meckel's Diverticulum Scan
Bone Marrow Scan