Dosimetry of chimeric TNT in lung tumor patients

The purpose of this study was to assess the absorbed dose of tumor and main critical organs in 131I labeled chimeric tumor necrotic treatment (chTNT). In 9 patients, a single intravenous dose of (29.6 ± 3.7) MBq/kg was administered. Blood samples were drawn at different time intervals, and urine was collected for up to one week. Tissue distribution of 131I-chTNT was followed for up to one week by gamma camera imaging. Absorbed doses to the whole body and to normal organs were computed according to the MIRD scheme using Mirdose-3 software. S-factors for lung tumors were estimated by comparison with lungs of similar mass and position in the body. It was found that mean serum disappearance half time values for 131I-chTNT were (4.93 ± 9.36) h and (61.7 ± 21.2) h for α, β respectively, while that for whole body was(99 ± 10) h. Mean urine biological clearance half time value was (90 ± 10) h. The absorbed dose to tumor was (8.28 ± 2.65) Gy, and the tumor-to-nontumor dose ratio was 3.95 ± 1.55. And the mean effective dose to patients was (1.02 ± 0.29) mSv/MBq.