Experimental Study On ^99mTc-HL91 And ¹⁸F-FDG Dual-isotope Imaging To Identification Benign Nodules

Objective: This study adopts ^99mTc-HL91 and ¹⁸F-FDG on tuberculosis, inflammation Kunming mice model of biological research, and the distribution of ^99mTc-HL91 and ¹⁸F-FDG on tuberculosis, inflammation, mouse model to explore the ^99mTc-HL91 and ¹⁸F-FDG dual-isotope imaging to identify benign nodules of feasibility. To minimize ¹⁸F-FDG PET/CT examination the false-positive rate, so as to improve the accuracy of cancer diagnosis.Methods and Materials:1. GroupChoose 8 Kunming mice whose nodule growed well and had no remarkable difference as tuberculosis group, and randomly drawn only 6 do bio-distribution, including 3 do bio-distribution of ^99mTc-HL91, 3 do bio-distribution of ¹⁸F-FDG, the other 2 do ^99mTc-HL91 and ¹⁸F-FDG dual-isotope SPECT/CT imaging; Choose 8 Kunming mice whose nodule growed well and had no remarkable difference as inflammation group, and randomly drawn only 6 do bio-distribution, including 3 do bio-distribution of ^99mTc-HL91, 3 do bio-distribution of ¹⁸F-FDG, the other 2 do ^99mTc-HL91 and ¹⁸F-FDG dual-isotope SPECT/CT imaging.2. Process2.1 Animal bio-distribution experiment: Randomly selected 6 from group of tuberculosis, then randomly choose 3 inject ¹⁸F-FDG 3.7MBq (0.1mCi)/0.2ml from the tail vein, the other 3 inject ^99mTc-HL91 3.7MBq (0.1mCi)/0.2ml from the tail vein; Randomly selected 6 from group of inflammation, then randomly choose 3 inject ¹⁸F-FDG 3.7MBq (0.1mCi)/0.2ml from the tail vein, the other 3 inject ^99mTc-HL91 3.7MBq (0.1mCi)/0.2ml from the tail vein. After 60 minutes, according to the sequence of injection, extracted blood from eyeballs, kill the mice separate the heart, liver, spleen, lung, kidney, stomach, small intestine, muscle, bone and tumor samples rapidly, after washing, weighing, measuring calculating the radioactive counts per gram of each tissue (%ID/g) and calculating the radioactive uptake of tumor and non-tumor (T/NT), then doing statistical analysis.2.2 ^99mTc-HL91 and ¹⁸F-FDG dual-isotope SPECT/CT imaging: Inject the ¹⁸F-FDG 37MBq (1mCi)/0.2ml from mice's tail vein, after 30 minutes according to the sequence of injection, inject ^99mTc-HL91 37MBq (1mCi)/0.2ml an other 30 minutes later, respectively in accordance with the order of injection do SPECT/CT imaging, observing uptake of imaging tissue, and using the region of interested (ROI) technology, drawing the outline of the areas which are interested. Last, calculating the radioactive uptake of tumor and non-tumor (T/NT).2.3 Pathological examination: Fix the tumor samples of each group into 100mmol/L formalin 24 hours, embed with paraffin wax, and shape the wax. Resect into 5μm, mounted on the slides, bake 60 degrees for 24h, after the temperature cooling, routine HE dyeing and observe the pathological changes from the optical microscope. The acid-faststain: after the smear fixed by flame, add phenolic solution, making fire slowly heating, the temperature do not over heat, maintain about 5 minute. After the smear cooling, use 3% hydrochloric alcohol to decolor 20-60 seconds, shake the slide lightly until it emerge colorless or pink, then wash the smear, dip it into 1:10 complex alkaline liquid 30-60 seconds, after the smear dry, observe it from the optical microscope.Results:1. Results of the bio-distribution1.1 Tumor's uptake of ¹⁸F-FDG: the uptake of tuberculosis group is (72.47±11.64)%ID/g; the uptake of inflammation group is (9.77±0.12)%ID/g. tuberculosis and inflammation groups statistically significant (P=0.000<0.05), that means the uptake of ¹⁸F-FDG in tuberculosis group is obviously higher than inflammation.1.2 Tumor's uptake of ^99mTc-HL91: the uptake of tuberculosis group is (15.31±2.64)%ID/g; the uptake of inflammation group is (6.49±0.7)%ID/g. tuberculosis and inflammation groups statistically significant (P=0.000<0.05), that means the uptake of ¹⁸F-FDG in tuberculosis group is obviously higher than inflammation.1.3 The radioactive uptake of tumor and non-tumor (T/NT): in tuberculosis group the uptake of radioactive of ¹⁸F-FDG is (4.86±0.42),the uptake of radioactive of ^99mTc-HL91 is (1.25±0.03);In inflammation group the uptake of radioactive of ¹⁸F-FDG is (1.25±0.06),the uptake of radioactive of ^99mTc-HL91 is (1.20±0.49). Compare the uptake of ¹⁸F-FDG with the uptake of ^99mTc-HL91 in tuberculosis group, have statistically significant (p=0.023<0.05); Compare the uptake of ¹⁸F-FDG with the uptake of ^99mTc-HL91 in inflammation group, have no statistically significant differences (p=0.1>0.05); Compare the uptake of ¹⁸F-FDG in tuberculosis group with in inflammation group, have no statistically significant differences (p=0.079>0.05); Compare the uptake of ^99mTc-HL91 in tuberculosis group with in inflammation group, have no statistically significant differences (p=0.356>0.05)2. ^99mTc-HL91 and ¹⁸F-FDG dual-isotope SPECT/CT imaging2.1 ^99mTc-HL91 and ¹⁸F-FDG dual-isotope SPECT/CT imaging of tuberculosis group: The uptake of ¹⁸F-FDG is obvious; for ^99mTc-HL91 is not obvious. In the image of ^99mTc-HL91 SPECT/CT imaging, it is too difficult to distinguish between tuberculosis and normal tissue.2.2 ^99mTc-HL91 and ¹⁸F-FDG dual-isotope SPECT/CT imaging of inflammation group: The uptake of ¹⁸F-FDG is only a little, compared with the contralateral normal tissue, is no obvious difference; the uptake of ^99mTc-HL91 is not obvious, compared with the contralateral normal tissue, and is no obvious difference.3. The uptake of ^99mTc-HL91 in both tuberculosis group and inflammation group are not obvious.Conclusions:1. Tuberculosis has a higher uptake rate of ¹⁸F-FDG, and obviously higher than the contralateral normal tissue; for ^99mTc-HL91, it has a lower uptake, compared with the contralateral normal tissue, has no obvious difference. When doing ^99mTc-HL91 and ¹⁸F-FDG dual-isotope SPECT/CT imaging, because of the higher uptake of ¹⁸F-FDG, the tuberculosis's outline is imaged clearly. And because of the lower uptake of ^99mTc-HL91, the tuberculosis is not imaged, compared with the contralateral normal tissue, has no significant difference. We could conclude that ^99mTc-HL91 and ¹⁸F-FDG dual-isotope imaging can be applied to identify the benign nodules.2. Inflammation has a lower uptake rate of ¹⁸F-FDG, compared with the contralateral normal tissue has no obvious difference; for ^99mTc-HL91, it has a lower uptake, compared with the contralateral normal tissue, has no obvious difference. When doing ^99mTc-HL91 and ¹⁸F-FDG dual-isotope SPECT/CT imaging, because of the lower uptake of ¹⁸F-FDG and ^99mTc-HL91, the inflammation's outline is not imaged. Compared with the contralateral normal tissue, has no significant difference. We could conclude that ^99mTc-HL91 and ¹⁸F-FDG dual-isotope imaging can be applied to identify the benign nodules.