Preparation, analysis and application of [99mTc]Human Albumin Microspheres ([99mTc]HAM) for lung scanning

Kits were developed for the sterile labelling of Human Albumin Microspheres with 99mTc. The microspheres were prepared, sieved to get the desired particle size and autoclaved for sterilization. The spheres were treated with stannous chloride and the pH of the suspension was adjusted to 3.7 with phosphate buffer. After freeze-drying the contents of single reaction vials from different batches were reacted with 99mTc and the radiochemical yield (higher than 97%) was determined. The HAM kits were stable and the stability of [99mTc]HAM was followed for 5 h. Lung and liver uptake in mice was determined to be about 90 and 1% respectively. The preparation of [99mTc]HAM is performed in a single step process and excellent human lung scans were obtained.