Download Y6 RD Radiographic Beam Filtration

Y6-RD Radiographic Beam Filtration
The first half-value layer in terms of mm of aluminum must be measured. The
measured values must not be less than the values shown in Safety Code 35
Appendix VI for a selected X-ray tube voltage. For most x-ray tubes which can be
activated in excess of 80 kVp the standard is HVL > 2.3 mm Al at 80 kVp.
Y6 RD
Radiographic
Beam
Filtration
Comments
Equipment: Dose meter, aluminium filters.
A convenient way to hold the filters in place is the use of a 1
mm Al filter with Velcro straps to hold it around the
collimator/tube assembly. Further filters can easily be added
without the likelihood of the filters falling on and damaging the
meter.
For radiographic systems only one HVL will need to be
measured – at 80 kVp.
Procedure

Place dose meter probe on table top at 100 cm.

Collimate to size of detector

For DR systems move detector out of the beam

On console choose Table Top exposure

Select 80 kVp; make exposure with no filter; record
reading

Repeat with additional Al filters until reading reduces to
less than half

Remove Filters from collimator
X-ray tube
filters
minimum 30 cm


Some newer x-ray meters have built-in filters and can
estimate the filtration directly. Use this method if you know
the calibration to be correct.