Thulium-170

Last updated
Thulium-170
General
Symbol 170Tm
Names Thulium-170
Protons (Z)69
Neutrons (N)101
Nuclide data
Natural abundance Synthetic
Half-life (t1/2)128.6±0.3 d [1]
Isotope mass 169.93580709(79) [2] Da
Spin 1 [1]
Binding energy 1377937.45±0.73 [1] keV
Decay products 170Yb
170Er
Decay modes
Decay mode Decay energy (MeV)
β 0.968 [3]
EC 0.312 [3]
Isotopes of thulium
Complete table of nuclides

Thulium-170 (170Tm or Tm-170) is a radioactive isotope of thulium proposed for use in radiotherapy and in radioisotope thermoelectric generators.

Contents

Properties

Thulium-170 has a half-life of 128.6 days, decaying by β to 170Yb about 99.87% of the time, and by electron capture to 170Er about 0.13% of the time. [1] About 18.1% of β decays populate an excited state of 170Yb at 84.25474(8) keV and this produces the main gamma ray emission from 170Tm; lower-energy photons are also produced through X-ray fluorescence at 7.42, 51.354, 52.389, 59.159, 59.383, and 60.962 keV. [3] [4]

The ground state of thulium-170 has a spin of 1. The charge radius is 5.2303(36)  fm , the magnetic moment is 0.2458(17)  μN , and the electric quadrupole moment is 0.72(5)  eb . [5]

Proposed applications

As a rare-earth element, thulium-170 can be used as the pure metal or thulium hydride, but the most common form is as thulium oxide (Tm2O3) due to the refractory properties of that compound. [6] [7] The isotope can be prepared in a reactor by neutron irradiation of natural thulium, which has a high neutron capture cross section of 103 barns. [4] [7]

Medicine

In 1953, the Atomic Energy Research Establishment introduced thulium-170 as a candidate for radiography in medical and steelmaking contexts, [8] but this was deemed unsuitable due to the predominant high-energy bremsstrahlung radiation, poor results on thin specimens, and long exposure times. [9] However, 170Tm has been proposed for radiotherapy because the isotope is simple to prepare into a biocompatible form, and the low-energy radiation can selectively irradiate diseased tissue without causing collateral damage. [4] [10]

Radiothermal generator

170Tm2O3 has been proposed as a radiothermal source due to it being safer, cheaper, and more environmentally friendly than commonly used materials that contain isotopes such as plutonium-238. [11] [12] The heat output from a 170Tm source is initially much greater than from a 238Pu source relative to mass, but it declines rapidly due to its shorter half-life. [7]

References

  1. 1 2 3 4 Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  2. Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
  3. 1 2 3 "NuDat 3". www.nndc.bnl.gov.
  4. 1 2 3 Polyak, Andras; Das, Tapas; Chakraborty, Sudipta; Kiraly, Reka; Dabasi, Gabriella; Joba, Robert Peter; Jakab, Csaba; Thuroczy, Julianna; Postenyi, Zita; Haasz, Veronika; Janoki, Gergely; Janoki, Gyozo A.; Pillai, Maroor R.A.; Balogh, Lajos (October 2014). "Thulium-170-Labeled Microparticles for Local Radiotherapy: Preliminary Studies". Cancer Biotherapy and Radiopharmaceuticals. 29 (8): 330–338. doi:10.1089/cbr.2014.1680. ISSN   1084-9785. PMID   25226213 via Academia.edu.
  5. Mertzimekis, Theo J. "NUMOR | Nuclear Moments and Radii | University of Athens | since 2007". magneticmoments.info. Retrieved 12 November 2023.
  6. Walter, C.E.; Van Konynenburg, R.; VanSant, J.H. (6 September 1990). "Thulium-170 heat source". doi:10.2172/10156110. OSTI   10156110.
  7. 1 2 3 Dustin, J. Seth; Borrelli, R.A. (December 2021). "Assessment of alternative radionuclides for use in a radioisotope thermoelectric generator". Nuclear Engineering and Design. 385: 111475. doi: 10.1016/j.nucengdes.2021.111475 . S2CID   240476644.
  8. Hilbish, Theodore F. (November 1954). "Developments in diagnostic radiology". Public Health Reports. 69 (11): 1017–1027. doi:10.2307/4588947. ISSN   0094-6214. JSTOR   4588947. PMC   2024396 . PMID   13215708.
  9. Halmshaw, Ronald (1995). Industrial radiology: theory and practice (2. ed.). London: Chapman & Hall. pp. 59–60. ISBN   0412627809.
  10. Vats, Kusum; Das, Tapas; Sarma, Haladhar D.; Banerjee, Sharmila; Pillai, M.r.a. (December 2013). "Radiolabeling, Stability Studies, and Pharmacokinetic Evaluation of Thulium-170-Labeled Acyclic and Cyclic Polyaminopolyphosphonic Acids" (PDF). Cancer Biotherapy and Radiopharmaceuticals. 28 (10): 737–745. doi:10.1089/cbr.2013.1475. ISSN   1084-9785. PMID   23931111. Archived from the original (PDF) on 2023-11-12.
  11. Walter, C. E. (1 July 1991). "Infrastructure for thulium-170 isotope power systems for autonomous underwater vehicle fleets". Lawrence Livermore National Lab., CA (United States). OSTI   5491258.
  12. Alderman, Carol J. (1993). "Thulium heat sources for space power application". AIP Conference Proceedings. Vol. 271. pp. 1085–1091. doi:10.1063/1.43194.
Lighter:
thulium-169
Thulium-170 is an
isotope of thulium
Heavier:
thulium-171
Decay product of:
Decay chain
of thulium-170
Decays to:
erbium-170
ytterbium-170