What is the purpose of E-CT examination?

For your question, please refer to the following information:

Computerized tomography

ECT (Emission Computed tomography) is a single photon emission computed tomography scanner, which is the abbreviation of isotope emission computed tomography. Its principle is to detect the dynamic distribution of steady state in human body and image with instruments; Characterized by its function and metabolism. ECT is a high-tech technology that combines the principles of computed tomography (CT) and nuclear medicine tracing. ECT includes SPECT and PET.

E-CT is an emission computerized tomography method. Different from the usual CT, the radioactive source is in the imaging volume. E-CT imaging is to let the human body receive some radioactive drugs, which gather in an organ of the human body or participate in a metabolic process in the body, and then image the concentration distribution and metabolism of radionuclides in organs and tissues. Therefore, E-CT can not only obtain anatomical images of human organs, but also obtain physiological, biochemical, pathological process and functional images. E-CT includes three imaging devices: γ camera, SPECT and PET.

gamma camera

Gamma camera is a primary imaging medical equipment, which is mainly composed of detectors (including collimators, scintillation crystals, photomultiplier tubes, etc.). ), electronic reading system and image display and recording device.

Single photon emission tomography

The basic principle of single photon emission computed tomography (SPECT) is to inject or inhale radionuclides or drugs that can emit pure alpha photons into the human body, aim the probe of the imager at the examined organ, receive the radiation emitted by the examined part, then amplify the photoelectric pulse into signals through the photomultiplier tube, and the computer continuously absorbs the information for image processing and reconstruction. Finally, the examined organ is imaged through three-stage imaging technology. SPECT is mainly used to examine epilepsy with technetium 99 labeled compounds HM-PAO and CED. These radionuclides can selectively enter the brain and reverse cerebral blood perfusion. During the seizure of epileptic focus, the hypoxia of neurons during local discharge leads to the increase of lactic acid, which leads to the increase of regional cerebral blood flow and the decrease of cerebral blood flow between seizures. Compared with PET, the two imaging methods have similar effects and overcome the shortcomings of high price and complicated operation, so they are widely used in clinic.

Positron emission computed tomography (positron emission computed tomography)

Positron emission computed tomography (PET) is the most advanced medical diagnostic equipment at present. When the human body contains nuclides emitting positrons, the positrons can annihilate the surrounding negative electrons in a short distance (less than a few millimeters), resulting in a pair of γ photons, which move in opposite directions and have an energy of 0.5 1 1Mev. Therefore, human organs can be imaged by using two detectors with opposite positions.

Positron emission tomography (PET) system is a nuclear medical imaging equipment that has been widely paid attention to in clinic in recent years. It is regarded as one of the major developments of world medicine in 1990s and an epoch-making milestone in the history of nuclear medicine. Compared with other imaging technologies, PET imaging agent can be consistent with naturally occurring active molecules in the body to the greatest extent. In a sense, PET is the best imaging method connecting molecular biology and clinical medicine.

Compared with SPECT, PET has the advantage of high sensitivity and can be used for more accurate quantitative analysis. In addition, most of the radionuclides used are isotopes of natural elements in human tissues, which can be used for real tracing research. Therefore, PET has become the most ideal quantitative metabolic imaging technology and made many unique contributions to the progress of medicine. However, it is expensive, and it is difficult to popularize and apply because of the need to equip an accelerator and a labeling hot chamber for generating positron nuclides nearby (because the physical half-life of commonly used positron emitters is short). return