@article {Kodaira497, author = {Satoshi Kodaira and Yukie Morokoshi and Huizi Keiko Li and Teruaki Konishi and Mieko Kurano and Sumitaka Hasegawa}, title = {Evidence of Local Concentration of α-Particles from 211At-Labeled Antibodies in Liver Metastasis Tissue}, volume = {60}, number = {4}, pages = {497--501}, year = {2019}, doi = {10.2967/jnumed.118.216853}, publisher = {Society of Nuclear Medicine}, abstract = {We investigated the local concentration of α-particles from 211At-labeled trastuzumab antibodies against human epidermal growth factor receptor type 2 antigens in liver metastasis tissue of mice. Methods: Mice carrying metastatic cancer in their liver were injected with 211At-agent. After 12 h, the liver was removed and sliced, and 2 tissue samples of liver tissues without lesions and one containing metastatic lesions were mounted on the CR-39 plastic nuclear track detector. Microscope images of the tissues on the CR-39 were acquired. After irradiation for 31 h, the tissues were removed from the CR-39. A microscope image of α-particle tracks on the CR-39 was acquired after chemical etching. The positions of each tissue sample and the emitted α-particle tracks were adjusted to the same coordinates. Results: The positional distribution of α-particle tracks emitted from 211At was consistent within the tissue. The α-particle tracks were mainly allocated in the tumor region of the tissue. The absorbed dose in individual cells segmented by 10-μm intervals was obtained by the spectroscopic analysis of the linear-energy-transfer spectrum. The concentration efficiency{\textemdash}the track density ratio of α-particle tracks in the necrotized tissue, which was the tumor region, to the normal tissue{\textemdash}was found to be 6.0 {\textpm} 0.2. In the tumor region, the high{\textendash}linear-energy-transfer α-particles deposited a large enough dose to cause lethal damage to the cancer cells. Conclusion: The total absorbed dose ranged from 1 to 7 Gy with a peak at around 2 Gy, which would correspond to a 2{\textendash}3 times higher biologically equivalent dose because of the high relative biological effectiveness of the α-particles emitted from 211At.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/60/4/497}, eprint = {https://jnm.snmjournals.org/content/60/4/497.full.pdf}, journal = {Journal of Nuclear Medicine} }