Nuclear medicine examinations use a small amount of radioactive material that is injected, most usually into the patient’s vein, in order to examine a particular organ. The patient is placed under a diagnostic device – a camera. The procedure is selected based on the organ that is to be examined, e.g., simple static imaging, dynamic imaging, or a whole-body scan.
Positron Emission Tomography (PET).
This is a type of imaging method that can reliably detect and localise serious development of a disease. It is a highly specialised diagnostic method of the nuclear medicine. The use of this imaging method has been a big step forward in the area of medicine and it has saved countless lives. If your specialist recommends a PET scan, there’s no need to worry. Your doctor will get a physiological profile of your body, thus be able to identify the location of the disease more precisely and subsequently choose the appropriate treatment.
Single Photon Emission Computed Tomography (SPECT).
(SPECT - Single Photon Emission Computer Tomography)
SPECT scan is a tomographic imaging that provides a three-dimensional image of the examined organ and shows the organ in various cross-sections. It allows for a more sensitive and precise imaging of the smaller focal points of disease. During the examination, there are usually two detectors circulating the patient’s body and continually recording it from different angles.
PET/CT is a PET imaging test combined with a simultaneous CT scan. During a CT scan, the patient’s body is exposed to X-rays that show detailed images of the shapes and structures of the particular organs. For a better distinction of the organs, it is sometimes necessary to administer the contrast material intravenously. A combined PET/CT scan represents one of the most prominent diagnostic tools of modern medicine. PET and PET/CT are mostly used in oncology diagnostics and in relation to neurological and cardiovascular diseases. It is a very effective method to confirm or exclude the presence of a tumour, assess its aggressiveness, and detect whether the tumour is spreading in the organism. It can also provide an answer to the question of how the disease is responding to the treatment or whether the patient has been healed completely.
What is Positron Emission Tomography?
The basis of this diagnostic method is formed by positrons emitted from a radioactive material. In order to explain the principle to the readers without the intricate medical terms, let’s have a more simplified look at the procedure, despite it being the result of many years of research.
Before the examination, the patient receives a glucose-based radioactive medicine, in other words a radiopharmaceutical, into the vein. In most cases, it is the Fluorodeoxyglucose (18F). The amount of radiation doesn’t pose a risk to you. It is usually compared to the amount of radiation used in two X-ray exams of the chest. In the human body, this material acts like a glucose, which means that the cells can absorb it as a source of energy. Once the cells absorb the “marked” glucose, the PET device is able to scan the level of positron radiation emitted from the cells using its rings (a big white tunnel). The positrons are emitted from the radioactive material that the cells have absorbed. Based on the levels of radiation in the particular tissues, doctors can diagnose the differences in the organ, tissue, and cell structures.
Which diseases can be detected by Positron Emission Tomography?
The radioactive material spreads via blood into the whole body. During the examination, the doctors are looking for any deviations from normal – that is, whether the cells have absorbed more or less of the modified glucose.
Positron Emission Tomography is mostly used for the oncology diagnostics and the assessment of the effects of the anticancer therapy. The cancer cells and tumours absorb a lot larger amount of glucose than healthy benign cells, so the radioactive material gathers in them and emits a larger number of positrons causing the area to clearly differentiate itself in the final image.
It can also be used for the diagnostics of heart diseases, especially when it comes to the blood supply to the heart. PET scan can detect scar tissue, lower heart function, and coronary artery diseases. It has also found its use in neurology, in particular in the mapping of brain activity and imaging of the developing inflammation in the body. These tissues consume glucose in higher amounts than healthy tissues.
In diagnostic centres, there are mostly PET/CT scans in use. Positron Emission Tomography can recognise the biological functions of the body, but it has a lower resolution for imaging. Therefore, in order to determine the precise location and shape of the affected area, we use the technology called Computer Tomography, also known as CT.