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 (T1/2 = 11.4 d), Rn-219 (T1/2 = 4 s), Po-215 (T1/2 = 1.8 ms), Pb-211 (T1/2 = 36 min), Bi-211 (T1/2 = 2.2 min) and Tl-207 (T1/2 = 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 .


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


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


No carrier added (n.c.a.)

Production routeAc-227→Th-227 generator
DaughterDecay 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-life18.7 d
Primary Container2.5 mL borosilicate glass V-vial with silicon rubber screw cap
Product GradePreclinical, n.c.a.
Physical FormSolid
Chemical FormDried nitric or chloridic form
Radioactive Concentration (gamma spectrometry)n.a.
AppearanceDried 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 Activityn.a.
Microbiological qualityn.a.
Bacterial endotoxinn.a.
pH (pH strips)n.a.
Additional information
Activity availableFew MBq upon request
Activity limit for UN2910 (excepted package) shipment5 MBq in dry state (consider also grow-in of Ra-223!)
Other information


  • α-therapy

Point of supply

  • Karlsruhe, Germany

Involved production facilities

JRC, International

Involved biomedical facilities

To find out in which biomedical facilities you can use this radionuclide, contact the helpdesk.