Renal dynamic imaging Renal dynamic imaging includes renal artery perfusion imaging, which reflects renal blood flow, and renaldynamic imaging, which reflects renal function and upper urinary tract drainage. The imaging agent is injected intravenously into the renal parenchyma and is rapidly discharged with the urine stream, and the radiological images of both kidneys are rapidly and dynamically acquired by SPECT/CT. These sites are sequentially visualized. Methods (1) Subjects were fed as usual, drank 300 ml of water 30 min before imaging, and took a sitting position after urination, and acquired posterior renal images with the γ-camera probe on their backs, with the field of view including both kidneys and part of the bladder (Figure 1). Immediately after the “bullet” injection of the imaging agent at a rate of 1~2s per frame for 30~60s, the renal artery perfusion image is obtained; immediately followed by a rate of 1min per frame for 20~30min, the renal dynamic image is obtained. (2) The commonly used imaging agents are divided into two categories: ① Glomerular filtration type: the imaging agent is mainly filtered into the kidney by the glomerulus, not reabsorbed by the renal tubules, and then quickly excreted with the urine. Commonly used is Tc-DTPA (Tc-diethylenetriaminepentaacetic acid), the amount of 111-296MBq (3-8mCi), the volume is less than 1ml. ② tubular secretory type: when the imaging agent flows through the kidney with the blood, most of it is absorbed by the proximal epithelial cells of the tubule, then secreted into the lumen, and a small part is filtered by the glomerulus, and the two are collected in the lumen of the tubule and excreted with the urine. Commonly used are I-OIH (I-o-iodomalurate), dosage 7.4-11.1 MBq (200-300 μCi), volume less than 1 ml; TcCEC (Tc-bis-cysteine) or TcCMAG3 (Tc-mercaptoacetyltriglycine), dosage 111-296 MBq (3-8 mCi), volume less than 1 ml. Curve generation and quantitative analysis Using the computerized region of interest (ROI) technique, the time-radioactivity curve (timeactivitycurve) of the first time phase (the first 30-60 s) was the renal artery perfusion curve, and the parameter peaktime (peaktime) and peakvalue (peakvalue) could be obtained. The second time phase (20-30 min) of the time-radioactivity curve is the renogram. The renogram is normal. Take the Tc-DTPA renal dynamic imaging as an example: 1. About 2s after the renal perfusion image of the upper abdominal aorta is visualized, the bilateral renal shadow is faintly visible, followed by the obvious renal shadow, with the complete morphology of the bilateral renal shadow and basically uniform distribution of radioactivity. The time difference between the appearance of the two renal shadows was <2s, and the peak difference was <30%. 2, renal dynamic image after intravenous injection of developer, the first minute of the double kidney shadow has been developed, 2-4min when the double kidney shadow is the most dense, the image is complete and clear, uniform distribution of radioactivity, for the renal parenchyma image. 3-5min later, the radioactivity in the renal calyces and renal pelvis can be seen gradually concentrated. With the concentration of radioactivity in the renal pelvis, the renal cortical image gradually faded, and then the bladder image gradually became obvious, and by 20 min the renal image basically faded, and most of the imaging agent was concentrated in the bladder.