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Nuclear Data Sheets for A = 209

The experimental data are evaluated for known nuclides of mass number A = 209 (Au,Hg,Tl,Pb,Bi,Po,At,Rn, Fr,Ra,Ac,Th). Detailed evaluated level properties and related nuclear structure information are presented, with the best values recommended for level energies, half-lives, γ–ray energies and intensities, decay data (energies, intensities and placement of radiations), and other spectroscopic data. This work supersedes the earlier full evaluation of A = 209 by M.J. Martin (1991Ma16)

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Sci-Thur AM: YIS – 01: New technologies for astatine-211 targeted alpha therapy research

Purpose: The short-range, densely ionizing α-particles emitted by {sup 211}At (t{sub 1/2}=7.2h) are well suited for the treatment of diffuse microscopic disease, using cancer targeting biomolecules. {sup 211}At availability is limited by the rarity of α-cyclotrons required for standard production. Image-based dosimetry is also limited for {sup 211}At, which emits low intensity X-rays. Our goal was to leverage state-of-the-art infrastructure at TRIUMF to produce and evaluate two related isotopes, {sup 211}Rn (t{sub 1/2}=14.6h, 73% decay to {sup 211}At) as a generator for {sup 211}At, and {sup 209}At (t{sub 1/2}=5.4h, X-ray/gamma-ray emitter) as a novel 211At surrogate for preclinical imaging studies. Methods: Produced by spallation of uranium with 480 MeV protons, mass separated ion beams of short-lived francium isotopes were implanted into NaCl targets where {sup 211}Rn or {sup 209}At were produced by radioactive decay, in situ. {sup 211}Rn was transferred to dodecane from which {sup 211}At was efficiently extracted and evaluated for clinical applicability. High energy SPECT/CT was evaluated for measuring {sup 209}At activity distributions in mice and phantoms. Results: Our small scale {sup 211}Rn/{sup 211}At generator system provided high purity {sup 211}At samples. The methods are immediately scalable to the level of radioactivity required for in vivo experiments with {sup 211}At. {sup 209}At-based high energy SPECT imaging was determined suitable for pursuing image-based dosimetry in mouse tumour models. In the future, we will utilize quantitative {sup 209}At-SPECT for image-based dose calculations. Conclusion: These early studies provided a foundation for future endeavours with {sup 211}At-based α-therapy. Canada is now significantly closer to clinical targeted α-therapy of cancer.

60 APPLIED LIFE SCIENCES↗