ESET 122
Chemistry Applications and
Climate
Lecture 7B
Nuclear Chemistry (Uses of Isotopes)
Dr. Jovan Stefanovic
Uses of Isotopes
Chemical Analysis
Isotopes, especially radioactive isotopes that are used to trace the
path of the atoms of an element in a chemical or biological process,
are called tracers.
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Uses of Isotopes
Isotopes in Medicine
Tracers are used for diagnosis in medicine:
• Sodium-24 injected into the bloodstream can detect possible
constrictions or obstructions in the circulatory system.
• Iodine-131 has been used to test the activity of the thyroid gland.
• Iodine-123 is used to image the brain.
• Technetium – 99m
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Uses of Isotopes
Isotopes in Medicine
Technetium is one of the most useful elements in nuclear
medicine.
All its isotopes are radioactive.
In the laboratory it is prepared by the nuclear reactions
“m” denotes that Tc is in its
98
99
1
42Mo + 0n → 42Mo
excited nuclear state .
Mo - Molybdenum
99
99m
0
When excited atomic states decay,
Mo
→
Tc
+
𝛽
−1
42
43
energy is released by fluorescence.
Or emits high-energy photons called gamma rays
Technetium 99m or 99mTc is injected intravenously into the arm and images of the thyroid are obtained with a
scintillation camera approximately 20 minutes later. The radionuclide emits gamma rays (photons) at a predictable rate.
The camera is set to detect a predetermined minimum number of photons. Also images for heart , liver and lungs.
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98
99
1
Mo
+
n
→
0
42
42Mo
99
99m
0
Mo
→
Tc
+
−1𝛽
42
43
Ground state is 99Tc
Molybdenum - 99 decay
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Uses of Isotopes
Boron Neutron Capture Therapy (BNCT)
Boron -10 compound is selectively taken up by tumor cells
and then applying beam of low energy neutrons to tumor side
10B capture a neutron to produce 11B , which disintegrates:
The highly energetic particles produced by this reaction
destroy the tumor cells in which the 10B is concentrated
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