chapter 11, (7 th ed) equipment design for radiation protection

Chapter 11, (7th ed)

Equipment Design for Radiation Protection

Radiographic equipment which is designed to protect the Rt and the patient

Collimation is always important for the Pt. as well as the RT

This is known as a diaphragm

Seldom used currently due to computerized imaging systems

Filter (The best thing ever invented to reduce Pt. dose)

Moly anodes used in Mammo to create a more monochromatic beam

Are grids radiation dose reduction devices?

CR VS Film

Pt. and Rt. protection

Image intensification

Dose reduction—What do you do?

Fluoro dose reduction

• Time• Collimate• Where do you stand?• Last image hold• Pulsed fluoro• High-level control VERY high dose to Pt & RT• See p. 236-8 box & table

List of dose reduction measuresX-ray housing/tube assembly:3 phase & high frequency generatorsStable high voltage generatorsCollimator on tube housing window to stop off focus radiationFiltration & heavy metal filtersAdequate collimationImage Receptor:CR / DR systems allow for higher KVP & total dose reductionReduction of repeatsWindowing and leveling allow for less images being produced.Fluoro Image ingtensifier, 5 minute timer, dead man switch, filter on fluoro tube, lead in table to protect Rad.Last image holdPulsed fluoroCTProtocols that reduce doseTHERE IS GREAT INTEREST IN DOSE REDUCTION IN ALL AREAS OF DIAGNOSTIC IMAGING TODAY.

(THERE ARE MORE. WHAT CAN YOU THINK OF?)

End Ch. 11 (7th ed.)

For an x-ray photon to be of any diagnostic value, what three things must happen to it?

Originate for close to a point source

Travel in a straight line

Stop in the pt. or continue on to the IR