To Evaluate The Effect Of Radiotherapy On Rats' Pulmonary Tumor Model With PET-CT

ObjectiveTo observe the effect of radiotherapy on Wistar Rats' Pulmonary Tumor Model for different stages , and then study how to select the best time of observation. Provide theoretical evidence for observing the effect of radiotherapy with PET-CT.Methods30 Wistar inbred strain rats(6-8weeks,weighed180-280kg,female,ordinary) were made into Lewis pulmonary tumor model rats. After 4-6 weeks that tumor model rats were made, when the greatest diameter of the tumor reached 1.5-2.0 cm, use PET-CT to gather the image; after imaging studies, carry out single time part therapy on tumor-bearing rats with the dose of 5Gy each time. After 3days,1 W,2W,3W,4W tumor-bearing rats receive PET-CT imaging for different stages. The aim is to observe and then evaluate the effect of radiotherapy. After that we take out the tissue of tumor, make one part of which into monoplast suspension, and make another part of which into chips of immunohistochemistry, in order to observe the expression of Glut-1.ResultsDifferent stages for radiotherapy on on Wistar Rats' Pulmonary Tumor Model have different ¹⁸F-FDG metabolism appearances of PET-CT. With the prolonged time of observation after the radiotherapy, the uptake of ¹⁸F-FDG reduces gradually, the activity of metabolism decreases by degrees too. Four weeks after the radiotherapy, the index of Semi-quantitation of SUV descent to 0.18±0.10 from 1.28±0.31 before radiotherapy.The result of flow cytometry detection: With the past time of observation after the radiotherapy , the percentage of apoptosis cell increases gradually . Four weeks after the radiotherapy, the percentage of apoptosis and dead increases from (4.26±3.04) % before radiotherapy to (70.39±7.13) %.The result of immunohistochemistry: The expression of Glut-1 is mainly located in the endochylema and the cell membrane. With the time past after the radiotherapy, the expression of Glut-1 (glucose transporter) for tumor tissue decreases gradually. The value of average optical density that Glut-1 expresses, decrease from 0.2558±0.03 before radiotherapy to 0.1320±0.04 after four weeks of radiotherapy.Pathology: Paraffin section display tumor cells analosis, fragmentation, necrosis increase gradually.ConclusionsThe effect of radiotherapy in Wistar rat's pulmonary tumor model using PET-CT is more better than that of use CT, moreover at the time of four weeks after radiotherapy, the effect of display of the radiotherapy is best.