Lung imaging

Lung imaging includes pulmonary perfusion imaging (Pulmonary Perfusion lmaging), pulmonary ventilation imaging (Pulmonary Ventilation lmaging) and lung tumor imaging. Pulmonary perfusion imaging shows the blood flow perfusion of lung tissue. The commonly used imaging agent is Tc-labeled macroalbumin (Tc-MAA). After intravenous injection of Tc-MAA37MBq (containing 0.5 mg of MAA, about 200,000 to 500,000 particles with a diameter of 10-60 μm), it can be temporarily and temporarily embolized in the pulmonary capillary bed. In direct proportion, because the capillaries of the embolism only account for one hundred thousandth of the total number of capillaries, it will not cause changes in cardiopulmonary hemodynamics and pulmonary function. Usually immediately after injection, normal people's lungs have clear images, the radioactive distribution is basically uniform, the blood flow in the apex of the lungs is affected by gravity, and the radioactivity is relatively sparse. Lung ventilation imaging reflects the gas filling of the alveoli in the respiratory tract and throughout the lungs. The subject inhaled radioactive gas such as Xe or Tc aerosol in the closed system, and imaging was performed after filling the airway and alveoli. Normal people show a uniform distribution of radioactivity in the airways and lungs. When the airway is narrow or blocked, or there is exudate or collapse in the alveoli, the ventilation volume or ventilation space is reduced, and the radioactivity is reduced or abnormal. Lung tumor imaging uses imaging agents such as Tc-glucose hydrochloric acid or Ca that are less concentrated in normal lung tissue but can be concentrated in lung cancer cells. After intravenous injection, lung cancer lesions can be clearly visualized. Benign tumors are also slightly concentrated, but the amount of aggregation is lower than that of malignant tumors.