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DIFFERENCE BETWEEN 'WET' COLUMN AND 'DRY' COLUMN 99mTc…
DIFFERENCE BETWEEN 'WET' COLUMN AND 'DRY' COLUMN 99mTc GENERATORS
Built design
problems and solution of the design
How elution is performed
The elution is performed with a set volume of saline provided each time by attaching a vial to an inlet to the generator.
The saline is pulled through the column by a vacuum provided by an empty evacuated vial attached to the outlet of the column.
The liquid pulled through the column is followed by an additional volume of air to effectively remove most of the liquid from the column.
Each elution pulls liquid from the column by a vacuum in an evacuated vial attached to the outlet of the chromatography column
This liquid is replaced by a volume of saline from the reservoir.
Thus the column remains full of saline between elutions
Radiation can cause radiolysis of water in a wet
generator resulting in the formation of H2O2 and HO2 free radicles
These species are oxidants and, if present in
the 99mTc, eluate can interfere with the technetium chemistry
The solution to the problem is by designing the dry column generator
Problems
The design was built to ensure the column stays dried
This causes the column to make contact with the water only during the elution process
Ensure the column remain dry after the process
Will not providing an environment for the formation of H2O2 and free radicles
Solution
Wet column
Has a large built-in reservoir permanently attached to the inlet for saline solution
Enough saline solution for all elutions
Low RCP
Effects
Gives unnecessary radiation exposure to patient
Results in suboptimal images due to the presence of radioactive impurities
Causes ?
Higher likelihood of production of H2O2 and free radicles
Water is continuously present in the column, enhancing the possibility for radiolysis of water
Dry column
Has a separate container of saline solution
The saline solution can be changed everytime when a new elution is made
High RCP
causes ?
Water is separated from the generator column
Decrease the probability of the radiolysis of water that generates H2O2 and free radicles
because of the Al2O3 column is in dried condition and not contact in water
Effects
Less radiation exposure to patient compare to wet column
Improved image qualities because lower impurities are present
The amount of saline used
Effects design on Radiochemical Purity (RCP)
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