SPECT is unique in dynamic functional examination or early diagnosis, which can reflect the tracer gamma-ray imaging emitted by patients. Common items include thyroid imaging, renal dynamic imaging, whole body bone imaging and myocardial imaging. SPECT is usually combined with CT and MRI to form higher-end PET/CT and PET/MR, which can more accurately find early tumors and tiny lesions.
PET is suitable for the physiological and functional detection of subjects, especially for the study of metabolic function. PET can reflect the metabolism of positron tracer drugs in human cells at the molecular level and observe the early functional changes of cells or tissues, which has the characteristics of high sensitivity, strong specificity and good quantification. PET equipment is usually combined with CT and MRI to form PET/CT and PET/MR, which can find lesions more accurately.
SPECT focuses more on functional examination and early diagnosis, while PET focuses more on the study of metabolic function and the display of lesions.
Imaging principles of SPECT and PET;
Imaging principle: SPECT images by detecting gamma rays emitted from patients, while PET detects annihilation radiation generated by the interaction between positrons and electrons in tissues, and then displays the internal structure and function of human body by detecting these annihilation radiation and reconstructing images.
Scope of application: SPECT is mainly used for thyroid imaging, renal dynamic imaging, whole body bone imaging, myocardial imaging and so on. Especially in the early diagnosis of cardiovascular diseases and tumors. PET is widely used in tumor, nervous system, cardiovascular system, endocrine system and other fields, especially in tumor diagnosis and staging.
Cost of use: SPECT equipment is relatively cheap, simple to operate and relatively low in inspection cost, which is suitable for use in primary hospitals. However, PET equipment is relatively expensive, complicated to operate and expensive to check. Generally, it is only used in tertiary hospitals or high-end physical examination centers.
In addition, there are some differences between SPECT and PET in image resolution, inspection time and radiopharmaceutical use, which will affect their application scope and use cost.