Nuclear medicine is a field of medicine in which diagnose and treatment of human diseases are investigated by the help of chemical molecules and biological meterials. Radioactivity, which is used for the benefit of humans for more than a century, is increasingly applied to the diagnoses and treatments of humans and provide data which could not be gained by any other method along with maintaining easier and more comfortable treatment options. Clinical nuclear medicine applications are generally grouped in three categories:

1. Radionuclide Therapy: This method is based on applying an ionized radiation to tissues and cells located at a limited distance and provide successful results in hyperthyroid and thyroid cancers, romatoid arthritis, lymphoma cases which do not respond to other therapies, and pain relief in bone metastases.

2. Non-imaging Diagnose Methods: Radioactive materials within the body are oriented to a target and subsequently measured from outside the body. For example, when iodine is introduced within the body, it accumulates in thyroid gland. By applying analyzes and measurements on thyroid gland at certain intervals, digital data about iodine metabolism can be obtained. Moreover, lately it has become extensively encountered that, many tissues which are very hard to detect by naked eye, may be determined by applying radioactive material and measurement devices during operations such as applied in breast cancer, parathyroid or colon cancer.

3. Imaging Diagnose Methods: Certain materials are directed to a certain target and those materials are imaged from outside the body. Three groups can be mentioned in terms of applied material and devices:

1. Planar Imaging: Frequently applied examples are thyroid scintigraphy, renal scintigraphy, whole-body bone scintigraphy. In planar imaging, gamma elucidating radioactive materials and gamma cameras are used for producing 2D images and many of the routine procedures are of this character.

   Whole-body Bone Scintigraphy	Thyroid Scintigraphy

   
   

2. a. SPECT (Single Photon Emission Computed Tomography) : The 3D imaging (or tomographic in other words) of the distribution of radioactive material inside the body. Myocardial perfusion scintigraphy (heart scintigraphy) and brain scintigraphy are such studies which are used frequently nowadays. This method, in which gamma radiation materials and tomographic gamma cameras are used; bone, kidney, lung scintigraphies may be applied tomographically as well.

   Myocardial Perfusion Scintigraphy	Brain Perfusion Scintigraphy

   
   

3. b. PET (Positron Emission Tomography) : The name of the tomographic imaging realized by special imaging devices and radioactive molecules which emit positron radiation. Today, it is most frequently used in imaging of the distribution of radioactive sugar (FDG). ?t is still known as the most sensitive method in determining tissues with cancer.

   Lung Cancer	Malignant Melanoma

Why are radioactive materials required for diagnose and treatment of diseases?

In order to investigate the events happening inside the human body before they cause a damage and/or discomfort, an agent which sends signal from inside the body is required. The gamma and positron radiations of the given radioactive materials can be determined and measured from outside the body; thus, the movements of the molecules labeled with a radioactive material can be tracked and reflected as images. Due to the mentioned characteristics of the radioactive materials, Nuclear Medicine applications; (i) are non-invasive (i.e. do not harm the patient or inflict any kind of discomfort), do not inflict any side effect or allergy; (ii) are very sensitive methods; (iii) are purpose-customized methods; (iv) provide data at physiological, metabolic, and molecular levels which can not be obtained by any other methods; (v) provide datas which are digital, so they can be compared and when repeated, those applications provide a great facility for determining normal and abnormal values

Do the materials used in nuclear medicine inflict any harm?

First of all, the radioactive drugs used in nuclear medicine cause no side effects or allergies. These materials can be used at age-spesific doses on patients of all ages including children. Patients receive a very low amount of radiation in nuclear applications. This amount is lower than the amount received during a routine x-ray application. In studies performed through a period of 60 years, no temporary or permanent damage induced by nuclear medicine applications was encountered yet.