Page 19 - Cellular Imaging in Regenerative Medicine, Cancer and Osteoarthritis

Radionuclides
A radionuclide is a radioactive form of an element. Some of them exist in nature, while others are man-made. Radioactivity can be used for many different purposes, i.e. to study living organisms, to diagnose and treat diseases, to produce energy for heat and electric power and it can be used to sterilize medical instruments and food, etc. Half-life is the time required for half of the radioactive atoms present to decay. The radiation that is emitted by a radionuclide does this at its own specific rate (https://www.epa.gov/radiation/ radionuclideswww.epa.gov/radiation/radionuclides). The half-life can range from milliseconds to millions of years, but clinically a half-life between 20 minutes and 10 days is most often used.
Two radionuclides have been applied in this thesis work. The first one is Indium-111, which is being applied for diagnostic imaging. It decays with a half-life of 67,9 h, emitting gamma-rays of 171 and 245 keV. Lutetium-177 is the second one and is being used for radiotherapeutic applications; it decays with a half-life of 161 h, emitting β− particles with a maximum energy of 498 keV. Also, low energy γ-rays of 113 and 210 keV are emitted, making this radionuclide suitable for theragnostic applications. Other radionuclides applied in nuclear medicine are presented in Table 1 (66) (https://www.nndc. bnl.gov/nudat2).
Table 1 Specifics and applications of some radionuclides frequently used in nuclear medicine.
Bismuth-213 0,76 Copper-64 12,7 Copper-67 61,9 Fluor-18 1,83 Gallium-68 1,13 Indium-111 67,9 Lutetium-177 161
Technetium-99m 6,02 Yttrium-90 64,1 Zirkonium-89 78,4
α (2), β− (98)
β+ (19), β− (40), Ɛ (41) β− (100), ɣ
β+ (97), Ɛ (3)
β+ (89), Ɛ (11)
Ɛ (100), Auger,ɣ
β− (100), ɣ
IT (99.99), ɣ (0,01) β− (100)
Ɛ (77), β+ (23)
225Ac/213Bi generator Cyclotron Accelerator Cyclotron
68Ge/68Ga generator Cyclotron
Reactor
99Mo/99mTc generator 90Sr/90Y generator Cyclotron
Therapy
PET imaging
Therapy
PET imaging
PET imaging
SPECT imaging
Therapy
+ SPECT imaging
SPECT imaging Therapy
PET Imaging
Introduction
Radionuclide
Half-life (h)
Type of decay (%)
Production mode
Used for
Ɛ = electron capture, IT= isomeric transition
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