[Nuclear medicine today]

This paper deals with those nuclear medicine investigations, which, in spite of development of other diagnostic methods and imaging procedures, remain important and in some cases, exclusive diagnostic tool in differential diagnostics of certain disorders and diseases.

Examination of myocardial perfusion with radiotracers is the only non-invasive imaging method. Typically two sets of images are acquired. The first one reflecting myocardial perfusion at peak stress (exercise) and the second set reflecting perfusion at rest. Fixed defects in the scintigrams show infarcted myocardiac regions. Thallium-201 exercise-rest perfusion imaging has a strong prognostic value for coronary artery disease.

Lung perfusion-ventilation scanning is an essentially non-invasive method of evaluating pulmonary embolism. Normal lung scan excludes clinically significant pulmonary embolism and patients with normal or very low probability perfusion scintigrams do not require therapy for pulmonary embolism.

Radioisotopes play an important role in the diagnosis of malignant bone lesions. Bone scanning is commonly used to detect metastases from malignant tumours, because it is more sensitive than x-rays. In benign bone diseases, scintigraphy is used to evaluate sports injuries, avascular necrosis and infection of joint prostheses.

Methods of nuclear medicine are useful for evaluating renal outflow obstructions, cortical and renovascular dysfunction. Normal finding of dynamic renography excludes an obstructive disease, whereas loss of radionuclide elimination after stimulation with furosemide is characteristic for it. In patients with suspected renovascular hypertension dynamic renography combined with captopril is a useful diagnostic test.

In patients with fever of unknown origin imaging with labelled autologous leukocytes may be used to establish the location in gastrointestinal, neurological, psychiatric and other disorders. Radionuclide investigations are helpful in diagnostics of some gastrointestinal disorders, such as diagnosis of malabsorption of vitamin B-12, malabsorption of bile acids or diagnosis of gastrointestinal bleeding caused by ectopic gastric mucosa in persisting Meckel's diverticulum. Cerebral blood flow studies and positron emission tomography are widely used in diagnostics of various neurological and psychiatric diseases. Thyroid scintigraphy is commonly used to assess a thyroid nodule. Radioisotopes are used to localize primary malignant tumors in oncology, and also they are used in therapy of certain disorders.

Nuclear medicine must remain an integral part of health care. Dental of nuclear medicine services, from professional point of view, is therefore unjustified.