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Basic radiopharmacy 1
1. Basic Radiopharmacy-1
M.R.A. Pillai Ph.D.; D.Sc.
Molecular Cyclotrons Pvt. Ltd
Cochin, India
Pillai.m.r.a@gmail.com
“Continuing Medical Education in Nuclear Medicine”
Christian Medical College
Vellore, Tamilnadu
23-24 April, 2021
2. Contents
• Milestones of Nuclear Medcine
• Radiopharmacy: PECT, PET and Therapy
• SPECT
• 99Mo/99mTc Generator
• Technetium Chemistry
• Different technetium radiopharmaceuticals
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3. In US, CT and MRI, the quality of
the image depends on the quality
of the machine..
In Nuclear Medicine, the quality
of the Image depends on the
Radiopharmaceuticals and the
machine
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5. Major Milestones in Nuclear Medicine
• 1940: Use of iodine-131 for therapy
• 1950: Use of different radiopharmaceuticals based on
isotopes such as 131I, 51Cr,57Co, 198Au,203Hg etc.
• 1960: Introduction of 99Mo/99mTc generator
• 1970: Freeze dried kits for 99mTc radiopharmaceuticals
• 1980: SPECT with 67Ga, 111In, 123I, 201Tl
• 1990: PET imaging using FDG
• 2000: Targeted therapy with 177Lu
• 2010: Gallium Radiopharmaceuticals
• 2020: Alpha therapy
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6. How to make the
radiopharmaceuticals?
• SPECT
• Use a generator and formulate radiopharmaceuticals
using lyophilized cold kits
• PET
• Use ready to use FDG or other F-18
Radiopharmaceuticals
• Preparation of 68Ga radiopharmaceuticals using
68Ge/68Ga generator and reagents either using synthesis
module or manually
• Therapy
• Use of ready to use radiopharmaceuticals
• Preparation of therapeutic radiopharmaceuticals using
radioisotopes and peptides
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7. SPECT Radiopharmacy
•Elution of 99Mo/99mTc generator
•Formulation of radiopharmaceuticals
using kits
•QC of the radiopharmaceuticals
•Stability of the radiopharmaceuticals
•Administration protocols
•Imaging protocols
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9. Why do we need a generator?
• Technetium-99m has a short half life, 6 hours
• Difficult to transport
• Most of the of the isotope will decay during
transport
• Better to buy the parent radionuclide
Molybdenum-99 having a half life of 67 hours
• Two different elements and hence 99mTc can be
easily separated
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10. 99Mo/99mTc generator
b- b- b-
99Mo 99mTc 99gTc 99Ru
T1/2 67 hrs T1/2 6 hrs T1/2 2.1x105 y Stable
• T1/2 of daughter< T1/2 of Parent
• If the ratio is less than 10, it is transient
equilibrium
• If the ratio is more than 10, it is secular
equilibrium
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16. 99Mo/99mTc generator
• The generator can be used for one week by which
time the activity will come to one fourth of the load
• The generator can be eluted every 24 hours by
which time about 94% saturation takes place
• A repeat elution after 6 hours will yield about
50% of activity 99Mo load
• Generator yields 99mTcO4
-
• Sodium pertechnetate is a radiopharmaceutical
used for thyroid uptake studies
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17. How come the same 99mTc gets
into different organs?
18. Chemistry of technetium
• Man made element
• Z=43
• Group VII element
• 1S2, 2S2,P6 d10, 3S2P6d10, 4S2P6 d5, 5S2
• Technetium can exist in 8 oxidation states
• -1 to +7
• Forms complexes with different Oxidation states
• Octahedral complexes
• Complexes with a variety of chelating agents
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25. Problems in Kit Formulation
•Poor complexation yields
• Ligand is insufficient
• Reducing agent insufficient
• Poor adjustment of pH
• Insufficient heating
• Insufficient time of reaction
• Generator not eluted for long time
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26. Problems in Kit Formulation
•Radiochemical purity will be poor
•QC check by TLC, PC etc.
•Poor quality images
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27. Good Radiopharmacy Practices
• Radiopharmaceuticals are injectable
products
• They need to be prepared under aseptic
conditions
• Free from pyrogens and microorganisms
• At most care is needed while preparing
radiopharmaceuticals
• Use freshly formulated products
• Prepare as and when needed
• Do a Quality control check
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28. Take care of Radiation Safety of self,
patients and bystanders
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