Introduction to Nuclear Medicine
Nuclear Medicine is the branch of medicine that utilizes minimal quantities of disease-targeted radioactive probes called radiotracers for evaluating the function of various organs, diagnosing different cancers, and treating diseases. It assesses the functionality of tissue at the molecular and cellular level using special scanners like PET/CT and Gamma Camera. The main advantage of nuclear medicine lies in the early detection of different diseases at the molecular level before anatomical changes imaged by CT or MRI set in. Additionally, the physiological and metabolic information provided by these specific radiotracers enables us to assess early response to treatments which often alters the treatment strategy.
Therapeutic nuclear medicine uses very targeted alpha and beta particle emitting radioisotopes to specifically destroy diseased cells. They are used in the treatment of various cancers and non-cancerous conditions with minimal side effects.
At Globe Healthcare, we have a state-of-the-art Nuclear Medicine Department, complete with Digital PET-CT (first in the state of Uttar Pradesh), Dual head Gamma Camera and radionuclide therapy unit.
Nuclear medicine procedures are safe, easy to perform, non-invasive and impart minimal radiation. With digital PET-CT, we are further able to perform the scans at half the radiation dose and scan time for benefit of our patients.
Radionuclide therapies use very specific alpha and beta emitting radionuclides which specifically destroys the diseased cells without harming the normal tissue making them very safe and effective.
Positron Emission Tomography (PET)
Positron Emission Tomography (PET) is cutting-edge technology in the armamentarium of diagnostic nuclear medicine, particularly in cancer imaging. This modality uses the administration of tumor-specific ‘positron isotopes’, which emit annihilation photons imaged by PET/CT scanners. The most commonly used radiotracer is 18F-FDG which is a radioactive analog of glucose. Most cancer cells are glucose hungry and utilize more glucose compared to the normal tissue. Thus, FDG helps us to study the metabolic behavior of cancer cells earlier and more accurately than the conventional radiological modalities like CT scans and MRI.
PET scan combined with a whole-body diagnostic CT scan often serves the purpose of a “one-stop shop” for the cancer work-up.
There are many more new radiotracers; some of them are already in clinical use, and many others are in the pipeline at various stages of clinical trials, which can give us a better understanding of many disease processes.
- 18F-FDG: Most versatile radiotracer which tells about glucose metabolism in tumors/inflammation.
- Lymphoma, lung cancer, breast, large and small bowel, Paraneoplastic, multiple myeloma, melanoma
- 68Ga/18F-PSMA: Prostate cancer
- 68Ga-DOTATATE: Neuroendocrine tumors, paraganglioma, pheochromocytoma, opsoclonus myoclonus syndromes, meningiomas, Tumour induced Osteomalacia, Paraneoplastic, medullary thyroid cancer.
- Tumor microenvironment.
- 68Ga-exendin: for insulinoma
- 18F-DOPA: Neuroendocrine tumors, Medullary thyroid cancer
- 68Ga-PENTIXOFOR: multiple myeloma, lung cancer, brain tumors
Gamma camera procedures
Gamma camera helps to image different organs using various 99mTc labeled radiotracers. Some of the commonly used gamma camera procedures are:
- Renal scans: DTPA, DMSA, EC
- Stress Myocardial perfusion Imaging (stress MPI) or Stress Thallium
- Myocardial Viability scan
- Thyroid scan
- Parathyroid scan
- Bone scan
- Three-phase bone scan for bone infections
- Brain scans: Tro-DAT for movement disorders, ECD/ HMPAO for brain perfusion
- HIDA scan for hepatobiliary system
- Lymphoscintigraphy
- MUGA scan
- Meckel’s scan
- G.I Bleed scintigraphy
Radionuclide therapies
Nuclear medicine therapies use specific radionuclides, which emit Beta particles (131-Iodine, 177-Lutetium,153-Samarium) or Alpha particles (225-Actinium) to treat different diseases.
Commonly used radionuclides are:
- Radioactive Iodine (131-I): Graves’ disease, Toxic adenoma, Toxic MNG, Thyroid cancer
- 177-Lu/225-Ac DOTATATE: For Neuroendocrine Tumours
- 177-Lu/225-Ac PSMA: For Prostate cancer
- Radio synovectomy: 177-Lu colloid
- Trans arterial radioembolization (TARE): Hepatocellular carcinoma, liver metastases
- Bone pain palliation: 177-Lu EDTMP, 153-Samarium