<sup>99m</sup>Tc-1-Thio-D-Glucose in Lymphoma Patients: Safety, Pharmacokinetics and Dosimetric Characteristics

Abstract

Purpose : To study the safety of 99m Tc-1-Thio-D-Glucose ( 99m Tc-TG) using, as well as its pharmacokinetics and dosimetric characteristics. Material and methods : The pharmacokinetics of 99mTc-TG was studied in 12 patients with lymphomas. The study was performed after a bolus injection of 729 ± 102 MBq 99m Tc-TG. Whole body anterior and posterior planar imaging was performed at 2, 4, 6, and 24 hours post-injection. In addition, all patients underwent SPECT/CT scanning at 2 hours and only SPECT at 4 and 6 hours after injection. To determine the dynamics of 99m Tc-TG accumulation in organs and tissues, the corresponding regions of interest (ROI) were outlined on each of the scans. Absorbed doses were calculated using a specialized OLINDA/EXM 1.1 program using phantoms of adult women and men. Results : The study showed that the administration of 99m Tc-TG is well tolerated by patients and is not accompanied by any side effects. The specified radiopharmaceutical has favorable dosimetric properties. Thus, in the present study, effective doses ranged from 5.0 to 9.8 mSv. SPECT/CT revealed high uptake of 99m Tc-TG in all nodular lesions detected according to standard diagnostic methods. There was also agreement between visualization of extranodal lesions using 99m Tc-TG SPECT/CT and standard diagnostic methods in all cases of the brain, neck, chest and abdomen lesions. In our study, the use of 99m Tc-TG SPECT/CT allowed us to detect a bone lesion that was not visualized on CT. This finding was an indication for an additional MRI examination, which confirmed a lymphoma lesion of the humerus. 2 hours after the injection of 99m Tc-TG, the tumor-background ratio reached 3.3 ± 1.2, then decreased to 2.30 ± 1.42 after 4 hours and then did not change significantly, so the optimal time for performing SPECT is 2 hours after the introduction of 99m Tc-TG. Conclusion : 99m Tc-TG is well tolerated by patients and has favorable dosimetric properties. 99m Tc-TG SPECT/CT may become the only method for molecular imaging of lymphoma in patients living in countries and regions with limited or no access to PET.