Prostate scintigraphy is a method of non-invasive examination of the gland using radioisotopes, the radiation of which is recorded in a special gamma camera. The technique allows you to evaluate the shape and size of the organ, as well as get an idea of the function of the gland. It is prescribed for the detection of local and diffuse pathologies of the structure, is used in the differential diagnosis of benign and malignant formations. Prostate scintigraphy is performed on an outpatient basis after preliminary injection of a radiopharmaceutical into the blood. Images in the front and rear projections are taken after 30 minutes and a day later. The technique can be combined with CT of the prostate gland to clarify the topography of the organ.
The main indication for the study is the presence of prostate cancer with suspected metastasis. In addition, this technique can be used to differentiate between benign and malignant tumor processes in the prostate.
Leading indications for prostate scintigraphy:
- diagnosis of prostate adenoma;
- differential diagnosis in the detection of a volumetric neoplasm of the prostate;
- detection of residual tumor cells in the presence of highly differentiated cancer;
- detection of residual cells after chemotherapy;
- diagnosis of the prevalence of metastases;
- diagnosis of prostate cancer recurrence.
Method of execution
At the preparatory stage of the study, the patient is injected with the drug. This is done 2-3 hours before the start of the scan. After intravenous administration, the patient can be free for three hours. During this period, doctors recommend drinking more fluids and going to the toilet to quickly remove the remnants of radioisotopes from the body. In addition, after intravenous administration, it is recommended to move more, which will reduce the radioactivity of isotopes and improve the quality of the study.
After the radionuclide substance has spread through the bone tissue, scanning begins using a gamma camera. This device evaluates the degree of accumulation of radioisotopes in tissues. For scanning, the patient is moved inside a special chamber to perform the study. The scanning stage takes no more than an hour. During this period, the patient should lie still so that the device can take as clear and informative pictures as possible. Scanning is done in several projections, which makes it possible to reliably detect areas of increased accumulation of radioactive substances. Those areas in which there is an increased content of the drug are called hot. They are the signs of metastasis and the development of the inflammatory process.
Radiopharmaceutical for prostate scintigraphy
To assess the intensity of accumulation of radionuclide isotopes during scintigraphy, a special radiopharmaceutical consisting of two components was developed. The main component is a radio marker, the radiation of which is read by a gamma camera. In addition to the radiomarker, the composition of the radioisotope preparation includes a special vector, the elements of which have certain chemical and biological characteristics. Thanks to these components, the radiopharmaceutical can accumulate in certain organs, for example, in bone tissue, lymph nodes, liver, and so on. To assess the presence and prevalence of metastases in prostate cancer, skeletal bone scintigraphy is used. Here, biphosphonate compounds are used as a guiding vector, which quickly enter the bone tissue.
Against the background of inflammation and actively growing metastases, the intensity of tissue processes increases, the intensity of accumulation of radionuclide drugs in bone tissue increases. Technetium-99m isotope is mainly used to detect bone metastases in prostate cancer. Radionuclide drugs can reach target organs in a certain period of time. Therefore, with scintigraphy of different zones, the time spent on conducting the study may vary. Skeletal scintigraphy takes the longest, which is necessary for prostate cancer. The time for this procedure is at least 2-3 hours from the moment of intravenous administration of the radiopharmaceutical.
The main contraindication to performing prostate scintigraphy is the presence of allergic reactions to the introduction of a radiopharmaceutical. However, allergy to the administration of these substances is relatively rare, so scintigraphy can be performed in almost all patients. The intensity of radiation exposure during prostate scintigraphy is much lower than during traditional radiography. Therefore, it can be carried out monthly, which makes this method very informative for evaluating the effectiveness of treatment and the dynamics of the course of the pathological process.