This document discusses the production and use of radiopharmaceuticals in nuclear medicine. It describes how the most commonly used radiopharmaceutical, Technetium-99m, is obtained from generators containing Molybdenum-99. Other radiopharmaceuticals like Iodine-131 are produced in reactors or cyclotrons. Radiopharmaceuticals consist of a radionuclide and a pharmaceutical designed to target specific organs for imaging or treatment. Their manufacture must follow strict good manufacturing practices and quality control procedures to ensure safety, purity and efficacy.

1. Radiopharmaceuticals

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Objective
To become familiar with the production and utilization of
radiopharmaceuticals used in nuclear medicine.

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Contents
• Production of radionuclides.
• 99Mo / 99mTc generators.
• Preparation of radiopharmaceuticals.
• Good manufacturing practice.

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• The primary radionuclide used for diagnostic nuclear
medicine procedures is Technetium-99m (99mTc).
• The primary radionuclide used for therapeutic nuclear
medicine procedures is Iodine-131 (131I).
Commonly used Radiopharmaceuticals

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• are constructed on the principle of the decay-growth
relationship between a long-lived parent and its short-lived
daughter radionuclide.
 i.e. a long-lived parent nuclide is allowed to decay to its
short-lived daughter nuclide and the latter is then
chemically separated.
e.g. 99Mo (T½ = 66.6 hours)  99mTc (T½ = 6 hours)
Radiopharmaceutical Generators
Radiopharmaceutical generators:

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• are easily transportable; and
• can serve as sources of short-lived radionuclides in
institutions located in remote areas where contracting the
services of a radiopharmacy is impracticable.
Radiopharmaceutical Generators (cont)
The importance of generators lies in the fact that they:

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Technetium 99m
99mTc labeled radiopharmaceuticals are easily produced
by simply adding 99mTcO4 to many choices of “cold kits”.

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In short, 99mTcO4 is added to a vial containing a chemical
compound that binds to the radionuclide. The result is a
radiopharmaceutical which will be taken up in the
designated organ for imaging (or analysis) with a gamma
camera.
Technetium 99m (cont)

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• is produced in a reactor;
Iodine 131
131Iodine:
• is used in diagnostic procedures
involving the thyroid and also for the
treatment of thyroid disorders;
• can be administered in capsule or liquid solution form;
• requires special precautions to be implemented during
administration.

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Industrial
cyclotron
Medical
Cyclotron
The production of other radionuclides for nuclear medicine
(e.g. PET) involves the use of a cyclotron.
Other Radionuclides

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• has two components; a radionuclide and a
pharmaceutical.
Principles of Uptake (localization)
A radiopharmaceutical:
In designing a radiopharmaceutical, a pharmaceutical is
first chosen on the basis of its preferential uptake
(localization) by a given organ or its participation in the
physiological function of the organ i.e. the morphology
and / or the physiology of the organ can be assessed.

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• As radiopharmaceuticals are intended for human
administration, it is essential that their manufacture is
subject to strict quality control procedures.
• These quality control procedures involve several specific
tests and measurements that ensure the purity, potency,
product identity, biologic safety, and efficacy of
radiopharmaceuticals.
Good Manufacturing Practice

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• physiochemical tests which indicate the level of radionuclide
and radiochemical impurities and determine the pH, ionic
strength, osmolality and physical state of the sample,
particularly if it is a colloid.
Good Manufacturing Practice (cont)
Radiopharmaceutical quality control tests fall into two categories:
• biologic tests which establish the sterility, non-pyrogenicity, and
toxicity of the material.

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• Quality control tests for the “kits” used to prepare
radiopharmaceuticals within a nuclear medicine
department are performed at the manufacturer’s facility.
• Generally, this is not an area of responsibility for the
regulator and therefore is not reviewed by the inspector
during a routine inspection.
Good Manufacturing Practice (cont)