Radiopharmacy Flashcards

1
Q

What is radiopharmacy?​

A

Involves preparation of radioactive materials for patient administration that will be used to diagnose and treat specific diseases in nuclear medicine.

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2
Q

What are the roles of a radiopharmacist​?

A

Activities/responsibilities:​

Formulation and stability of radiopharmaceuticals (RPs)​.
Managing the production of RPs​.
Health and safety for individuals dealing with RPs​

Clinical role: ​

Give advice on use of RPs​.
Give input to patient care​.

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3
Q

What is alpha decay?

A

A type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms or decays into a different atomic nucleus, with a mass number that is reduced by four and an atomic number that is reduced by two.

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4
Q

What is beta decay?

A

A type of radioactive decay in which a beta particle is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide.

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5
Q

What factors should be considered when radiopharmacy is carried out?

A

Location: near Nuclear Medicine Department ​

Layout: smooth orderly flow of work - separate rooms for separate purposes​.

​Budget: building costs, equipment, running costs, maintenance costs​.

Either (for a centralised facility):​

Full suite of rooms - clean room facilities​ - contained workstation​.

Or (local operation):​

Isolator - small workloads​.

RPs are sterile products, so must be in a sterile area e.g. at positive pressure. But, production area should be at negative pressure relative to the outside world.

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6
Q

What working practices should be followed?

A

Appropriate shielding - lead, tungsten, aluminium, perspex​.

Protective clothing / gloves​.

Contained workstation​.

Tray with absorbent tissue​.

Non-absorbent surfaces​.

Eating, drinking etc forbidden​.

Frequent monitoring​.

Use of fume cupboards for gaseous or volatile materials​.

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7
Q

What are radiopharmaceuticals​?

A

These are medicinal products which are radioactive.

Radiopharmaceuticals may consist of various chemical forms, contained in a variety of dosage forms.

A radiopharmaceutical is made by reacting the radionuclide with various ligands.

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8
Q

What are the advantages of the radionuclide (Technetium-99m​)?

A

Ideal physical properties for imaging (140keV)​.

Decays by pure gamma radiation​.

Technetium-99m​ decay to Tc rapid (short half-life, 6hrs). ​
Versatile coordination chemistry (forms complexes easily)​.

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9
Q

What is the mechanism of radiolabelling​?

A

Incorporation of a radionuclide into a molecule​:

Commonest method; join a radionuclide with a compound with desired biological properties, usually by covalent bonding (eg 99mTc labelled RPs, blood cells labelled with Tc, Cr or In). ​

Bifunctional chelates​:

Used for proteins/peptides.

A complex is formed between protein & a chelate, which is then labelled with radionuclide.

Isotope exchange reactions:

When compound of interest has an element which has a radioactive isotope – so replace a proportion of atoms with this isotope. Used to label with 14C, 32S, 3H, iodine​ ​

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10
Q

Why is technetium-99m used for radiolabelling​?

A

One reason that Tc is widely used is its diverse chemistry; it can exist in oxidation states from -1 to +7 (has 7 electrons in outer shells available for bonding).​

However, Tc in the various possible reduced states (+1, +3, +5) is relatively reactive, will readily bond to ligands, chelating agents.​

To lower the oxidation state of the Tc atom, (which can then bind to ligands) –​ a reducing agent is added (to reduce oxidation state of Tc). ​

The most common means of achieving this is by adding a stannous (tin) salt​.

Wide variety of bonding possibilities using all the reduced states of Tc – hence the popularity.

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11
Q

How are cold kits prepared?

A

Radioactive concentration of generator eluate is calculated, then appropriate volume of eluate is added to ‘cold kit’ using a syringe​.

Invert several times to mix​.

Incubate according to instruction for a few minutes (room temperature, or may require heat)​.

Individual doses are taken from the stock for named patients – syringe plus suitable shielding are sent for immediate administration​.

Each patient activity must be measured and recorded in the radiopharmacy log​.

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12
Q

How can quality assurance of radiopharmaceuticals​ be carried out?

A

Documentation: Guide to GMP – logs for receipt of materials, elution of generator. SOPs for preparation and supply of RPs. Tests on equipment, environment, radiation safety​.

Operator technique: broth transfer tests every 3 months​.

Equipment: regular checks on calibrators etc.​

Environment: contamination - particulate, microbial. Radioactive contamination of surfaces. Overpressures in sterile suite. Air flow rates, efficiency of filters​.

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13
Q

What tests should be carried out on the final product?

A
Radioactivity. 
Radionuclide identity​.
Radionuclide purity​.
Radiochemical purity.
Chemical purity.
Foreign particulate matter (use polarised light)​.
Particle size.
Sterility.
Pyrogens.
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14
Q

What are the different ways localisation occurs?

A

Physical - aggregates can get trapped in capillaries (eg in lung, pulmonary embolism)​.

Chemical - certain RPs are hydrophilic, localise in kidney​.

Biological - receptor imaging agents or antibodies bind to receptors or tumour-associated antigens​.

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15
Q

What are the methods of localisation​?

A
Capillary trapping.
Ion-exchange.
Aerosol deposition.
Transport mechanisms.
Phagocytosis and pinocytosis.
Metabolic incorporation.
Autologous products.
Immunological mechanisms.
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16
Q

What are erythrocytes used to investigate?

A

Blood volume, red cell volume​.

Site of red cell destruction, GI bleeding​.

Spleen activity, cardiac and vascular imaging​.

17
Q

What are leucocytes used to investigate?

A

Spleen, bone marrow, liver; sites of inflammation and infection (e.g. abscesses, lung infections)​.

Osteomyelitis, infections after hip surgery.

Inflammatory bowel disease​.

18
Q

What are platelets used to investigate?

A

Thrombosis, platelet life span. ​

Kidney transplants.

Heart imaging​.