227Th

Th 227

18.7 d

α 6.038, 5.978...

γ 236, 50, 256...

Chemical properties

Th-227 is usually in tetravalent state.

Nuclear properties

Th-227 decays by ɑ decay with a half-life of 18.68(9) days. Its decay chain involving Ra-223 (T_1/2 = 11.4 d), Rn-219 (T_1/2 = 4 s), Po-215 (T_1/2 = 1.8 ms), Pb-211 (T_1/2 = 36 min), Bi-211 (T_1/2 = 2.2 min) and Tl-207 (T_1/2 = 4.8 min) leads to stable Pb-207. Including its short-lived decay chain, the cumulative ɑ emission is 500% per Th-227 decay.

Th-227 emits γ-rays, notably at 236 (12.9%), its daughter Ra-223 emits X-rays from 81 to 98 keV (49.6%) and γ-rays, notably 269 keV (13.3%), its grand-daughter Rn-219 emits γ-rays at 271 keV (10.8%) and Bi-211 emits γ-rays at 351 keV (13%). These are the principal photon emissions of the decay chain that enable SPECT-imaging .

Production

Th-227 is produced at JRC Karlsruhe by chemical separation from an Ac-227 source.

Distribution

Radiochemical separations are performed at the production facility JRC Karlsruhe (JRC, Karlsruhe, International). Activity will be shipped from there to the users in dry form.

Examples of use

Antibodies were radiolabeled with Th-227 using DOTA as chelator , .
The octadentate chelator Me-3,2-HOPO enables chelation of Th⁴⁺ at ambient temperature, suited for radiolabeling of monoclonal antibodies with Th-227 , ,.

Purity grades available

research

preclinical

No carrier added (n.c.a.)

Yes

Parameter	Specifications
Production route	Ac-227→Th-227 generator
Daughter	Decay chain involving radioactive Ra-223, Rn-219, Po-215, Pb-211, Bi-211, Tl-207 leading to stable Pb-207: cumulative 500% α, 200% β^-
Half-life	18.7 d
Processing
Primary Container	2.5 mL borosilicate glass V-vial with silicon rubber screw cap
Product Grade	Preclinical, n.c.a.
Physical Form	Solid
Chemical Form	Dried nitric or chloridic form
Radioactive Concentration (gamma spectrometry)	n.a.
Appearance	Dried solid
Radionuclide identification (gamma spectrometry)	236 keV and 256 keV gamma lines present
Radionuclidic Purity (gamma spectrometry)	n.a.
Chemical purity (ICP-OES)	n.a.
Molar activity (ICP-OES)	n.a.
Apparent Molar Activity	n.a.
Microbiological quality	n.a.
Bacterial endotoxin	n.a.
pH (pH strips)	n.a.
Additional information
Activity available	Few MBq upon request
Activity limit for UN2910 (excepted package) shipment	5 MBq in dry state (consider also grow-in of Ra-223!)
Other information