In all, 32 radioisotopes of gadolinium have been characterized, with the three most stable being alpha emitters: 152Gd (naturally occurring) with a half-life of 1.08×1014 years, 150Gd with a half-life of 1.79×106 years, and 148Gd (theoretically not beta-stable) with a half-life of 86.9 years. All of the remaining radioactive isotopes have half-lives less than a year, the majority of these having half-lives less than two minutes. There are also 16 metastable isomers, with the most stable being 143mGd (t1/2 = 110 seconds), 145mGd (t1/2 = 85 seconds) and 141mGd (t1/2 = 24.5 seconds).
↑()– Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
↑#– Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
↑Bold half-life– nearly stable, half-life longer than age of universe.
123#– Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
↑Believed to undergo β−β− decay to 160Dy with a half-life over 3.1×1019 years
Gadolinium-148
As a pure alpha emitter with a half-life of 86.9±3.9years (the same as plutonium-238 within error),[2] gadolinium-148 would be ideal for radioisotope thermoelectric generators. However, gadolinium-148 cannot be economically synthesized in sufficient quantities to power a RTG.[11]
Gadolinium-153
Gadolinium-153 has a half-life of 240.6days and emits gamma radiation with strong peaks at 41 keV and 102keV. It is used as a gamma ray source for X-ray absorptiometry and fluorescence, for bone density gauges for osteoporosis screening, and for radiometric profiling in the Lixiscope portable x-ray imaging system, also known as the Lixi Profiler. In nuclear medicine, it serves to calibrate the equipment needed like single-photon emission computed tomography systems (SPECT) to make x-rays. It ensures that the machines work correctly to produce images of radioisotope distribution inside the patient. This isotope is produced in a nuclear reactor from europium or enriched gadolinium.[12] It can also detect the loss of calcium in the hip and back bones, allowing the ability to diagnose osteoporosis.[13]
↑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.
↑Sumikama, Toshiyuki; Fukuda, Naoki; Kubo, Toshiyuki; Suzuki, Hiroshi; Takeda, Hiroyuki; Inabe, Naohito; Kameda, Daisuke; Ahn, Deuk Soon; Murai, Daichi; Yoshida, Koichi; Kusaka, Kensuke; Yanagisawa, Yoshiyuki; Ohtake, Masao; Shimizu, Yohei; Sato, Yuki; Sato, Hiromi; Otsu, Hideaki; Baba, Hidetada; Lorusso, Giuseppe; Söderström, Pär-Anders; Isobe, Tadaaki; Imai, Nobuaki; Mukai, Momo; Kimura, Sota; Miyatake, Hiroari; Iwasa, Naohito; Yagi, Ayumi; Yokoyama, Rin; Tarasov, Oleg Borisovich; Geissel, Hans (15 February 2026). "Expanding the Isotopic Frontier: Seven New Neutron-Rich Rare-Earth Isotopes Observed at RIKEN RI Beam Factory". Journal of the Physical Society of Japan. 95 (2). doi:10.7566/JPSJ.95.024202.
↑National Research Council of the National Academies; Division on Engineering Physical Sciences; Aeronautics Space Engineering Board; Space Studies Board; Radioisotope Power Systems Committee (2009). Radioisotope Power Systems: An Imperative for Maintaining U.S. Leadership in Space Exploration. CiteSeerX10.1.1.367.4042. doi:10.17226/12653. ISBN978-0-309-13857-4.
↑"Gadolinium". BCIT Chemistry Resource Center. British Columbia Institute of Technology. Archived from the original on 23 August 2011. Retrieved 30 March 2011.
