NUCLEAR MEDICINE IMAGING (SPECT), or single photon emission computed tomography is a complex investigative method of nuclear medicine applied in clinical practice. This method is painless and is intended to visualise an organ, and, above all, to assess its function by means of small doses of radioactive isotopes (radiotracers). A radiotracer is a kind of contrast medium composed of an isotope emitting gamma radiation (most frequently technet Tc99m of T1/2 6 hours); scintigraphy is a recognised safe diagnostic method which helps doctors to undertake the correct treatment procedures.
The SPECT method is widely used in diagnostics such as endocrinology, oncology, as well as in some conditions of the nervous system, urinary or osteoarticular systems. It enables the examination of the cranial blood flow, the location of the cranial receptor, and enables the diagnostics of the brain by means of so-called oncophilic markers. It makes it possible to detect functional disorders of the investigated organs, frequently even before there is discernible evidence of morphological lesions, and facilitates accurate diagnoses. It helps to monitor the progression of the disease and the effectiveness of the treatment.
The isotope scan is not a dangerous examination. The absorbed dose does not exceed the double dose of the pulmonary x-ray, and in some cases is much lower. The radiotracer is administered intravenously through a cannula or needle, though some examinations require the oral administration of the isotope. During the scan the patient lies still for several minutes. The scan is carried out by means of a gamma camera. During this time the detector reads the location of the radiotracer in the patient’s body or its flow and excretion. The gamma cameras are the latest generation of nuclear medicine machines. The large head of this scanner covers the entire scanned organ (liver, heart, brain, kidneys), making the process is much shorter in comparison to traditional scintigraphy equipment. The result may be submitted as a computer picture depending on exact requirements - a change in colour scales, filtering, smoothing and examination of the functions of the organs are possible. The mobile (rotating) gamma cameras make it possible to obtain slice images (tomography), similar to computed tomography. These images are obtained from the circular movements of the machine head around the patient’s body.