Ra 224
3.63 d
α 5.685, 5.449
γ 241...

Chemical properties

Ra-224 is usually in divalent state.

Nuclear properties

Ra-224 decays by ɑ decay with a half-life of 3.6316(23) days. Its decay chain involving Rn-220 (T1/2 = 55.6(1) s), Po-216 (T1/2 = 145(2) ms), Pb-212 (T1/2 = 10.622(7) h), Bi-212 (T1/2= 60.55(6) min), either Po-212 (T1/2 = 0.29 µs) or Tl-208 (T1/2 = 3.053(4) min) leads to stable Pb-208. Including its decay chain, the cumulative ɑ emission is 400% per Ra-224 decay with an average ɑ energy of 6.75 MeV.

Ra-224 and daughters emit γ-rays and X-rays. Notable emissions are from Ra-224 at 241.0 keV (4.10(5)%), Pb-212 at 238.6 keV (43.6(5)%), Bi-212 at 727.3 keV (6.67(9)%) and Tl-208 at 2614.5 keV (99.754(4)%) and 583.2 keV (85.0(3)%).


Ra-224 is produced by high energy proton induced spallation of thorium targets at MEDICIS (CERN) followed by an off-line mass separation in order to get a pure Ra-224 sample. The mass-separated ions are implanted into a NaCl layer.


Ra-224 is produced at MEDICIS. Activity will be shipped from there to the users in liquid (0.5 M HCl) or dry form.

Examples of use

  • Ra-224 can serve in Pb-212 generators to provide Pb-212 that is used in turn as in-vivo Pb-212/Bi-212 generator. Different Ra-224/Pb-212 generator designs have been studied , , , etc.
  • Free Ra2+ ions act, analogously to Ca2+, as bone seekers. Ra-224 administered as chloride has been used clinically to treat ankylosing spondylitis
  • Ra-224 sources can serve for “Diffusing Alpha-Emitter Radiation Therapy”
  • Ra-224 has been labelled to micro- or nanoparticles. Ongoing clinical trials study treatment of peritoneal metastases , , ,
  • Stable chelation of Ra2+ with the chelator macropa has been reported E
  • SPECT imaging of Ra-224 in equilibrium with daughters has been reported

Purity grades available


No carrier added (n.c.a.)

Production routeTh-232(p,spallation)
DaughterDecay chain involving radioactive Rn-220, Po-216, Pb-212, Bi-212, Po-212 or Tl-208 leading to stable Pb-208: cumulative 400% α, 200% β-
Half-life3.6316 days
ProcessingOff-line mass separation
Primary Container
Product GradeResearch, n.c.a.
Physical FormLiquid or solid
Chemical FormDissolved in maximum 0.2 mL 0.5 M HCl, implanted in solid NaCl layer or deposited on a glass wool
Radioactive Concentration (gamma spectrometry)n.a.
AppearanceSee chemical forms available above
Radionuclide identification (gamma spectrometry)241 keV (Ra-224), 238 keV (Pb-212)
Radionuclidic Purity (gamma spectrometry)>99% (possibility of presence of small Ra-223/Ra-225 fraction)
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 available100 MBq, few times per year (planning several months in advance)
Activity limit for UN2910 (excepted package) shipment20 MBq (solid form) or 2 MBq (liquid form)
Other informationOther forms of delivery to be discussed


  • α-therapy
  • generator

Point of supply

  • Geneva, Switzerland

Involved production facilities

CERN, International

Involved biomedical facilities

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