Yb 175
4.16 d
β- 0.5...
γ 396, 283, 114...

Chemical properties

Yb-175 is a radiolanthanide, most often in trivalent state and chemically very similar to lutetium. The ionic radius of Yb3+ is 87 pm, i.e. differing by less than 1% from that of Lu3+, which explains that macrocyclic chelators suitable for Lu-177 can be directly employed for Yb-175 too, in particular DOTA. The ionic radius is 86.8 pm.

Nuclear properties

Yb-175 decays by beta-minus emission with a half-life of 4.1615(30) days to stable Lu-175. In addition to low-energy beta-minus emission (mean energy 113 keV, maximum energy 470 keV) it shows emission of low energy conversion and Auger electrons , thus emitting in total about 1.17 electrons (with energies above 6 keV) per decay.

Moreover Yb-175 emits gamma- and X-rays, notably 396.3 keV (13.2(3)%) and 282.5 keV (6.13(8)%). These make Yb-175 suitable for SPECT imaging with high energy collimators.

The mean electron energy emitted per decay is 120 keV, the mean photon energy per decay is 80 keV.


Yb-175 is produced by thermal neutron irradiation of enriched Yb-174 oxide targets in the high flux reactors of the PRISMAP production facilities: RHF at ILL or BR2 at SCK CEN.


Off-line mass separation is performed at the PRISMAP production facility MEDICIS (CERN, Geneva, Switzerland). Activity will be shipped from there to the users in form of YbCl3 solution or in solid form, implanted into an Al, Zn or NaCl layer.

Purity grades available


No carrier added (n.c.a.)

Available in n.c.a form (but not in theoretical specific activity)
Half-life4.16 d
DaughterStable Lu-175
Branching Ratio/Decay100% β-
ProductionYb-174(n,𝛾) Yb-175
PurificationOff-line mass separation + 2-steps column separation
Chemical FormIn 0.05 M HCl
Specific Activityn.a.
Radionuclidic Purity>99.9%
Radiochemical PuritySuitable for radiolabelling
Chemical Purityn.a.
IdentificationPresence of 396.3 keV and 282.5 keV gamma lines
AppearanceClear solution
Activity availableUp to 200 MBq
AvailabilityFew times per year (planning in advance), depends on reactor and MEDICIS schedule
Gradepreclinical, n.c.a.
Other informationResearch grade implanted in Al, Zn or NaCl layer on gold foil also possible


  • β-therapy

Point of supply

  • Geneva, Switzerland

Involved production facilities

ILL, France
SCK CEN, Belgium
CERN, International