Film Processing Q & A

Robert L. Metzger, Ph.D.

RAPHEX 2001 Diagnostic Question D9

The imaging System which is best for visualizing small high contrast objects is:A. Computed tomographyB. Film-screen radiographyC. Image intensified fluoroscopyD. Magnetic resonance imagingE. Ultrasound

RAPHEX 2001 Diagnostic Answer D9

B. Film-screen radiography

An example is microcalcifications on mammography

RAPHEX 2002 Diagnostic Question D21

Failure to use adequate fixer for radiographic film processing will:A. Decrease the film contrast gradientB. Decrease film speedC. Increase quantum mottleD. Increase silver reclamationE. Decrease archival storage

RAPHEX 2001 Diagnostic Answer D21

E. Decrease archival storageFixer removes the undeveloped silver grains from the film base. Failure to remove all the silver grains will result in darkening the film with time. Improperly fixed films will have a brown appearance after a number of years. Silver reclamation will decrease, but the fixer has no effect on film contrast, speed or quantum motile.

RAPHEX 2002 Diagnostic Question D22

Low specific gravity of the developer solution (dilution of the chemistry) for film processing will:A. Increase film contrast gradientB. Increase “base + fog”C. Decrease film speedD. Decrease archival storageE. All of the above

RAPHEX 2002 Diagnostic Answer D22

C. Decrease film speed

Lowering the specific gravity of the developer is similar to diluting the chemistry with water, and results in a lower film speed and lower film average contrast gradient. The developer has no effect on archival storage. Dilution of the chemistry will also decrease “base + fog” to its lowest level.

RAPHEX 2002 Diagnostic Question D23

Consider the three characteristic curves in the diagram. Which statement is false?

D23 Answer ChoicesA. System B has the highest contrastB. System C has the widest latitudeC. System A has the highest maximum densityD. System B has the highest base-fog densityE. System C is the fastest

RAPHEX 2002 Diagnostic Answer D23

E. System C is the fastestSystem A is the fastest, I.e., requires the

lower exposure to give a net density (density minus base + fog) of 1.0

RAPHEX 2003 Diagnostic Question D25

A radiograph with an optical density (OD) of 3.0: A. Transmits 1/3 times as much light as a film with

an OD of 1.0 B. Has a combined OD of 6.0 when placed over

another film of OD 2.0 C. Looks “light gray” on a standard view box D.Transmits 0.1% of the light incident upon it

RAPHEX 2003 Diagnostic Answer D25

D. Transmits 0.1 % of the light incident upon it

Optical densities are additive, so the net OD of both films is 5.0. An OD of 3.0 looks black on a standard view box.

OD=log10(I/T), where I and T are the incident and transmitted light intensities. For OD=3.0, T=0.001, and for OD=1.0, T=0.1

RAPHEX 2003 Diagnostic Question D29

The following film processor parameters all affect mammography image quality except:A. Nitrate depletionB. Developer concentrationC. Developer temperatureD. Replenishment ratesE. Developer immersion time

RAPHEX 2003 Diagnostic Answer D29

A. Nitrate depletion

B-E directly influence the density and speed of the various film/screen systems. Although bromine concentration in the developer affect both speed and contrast, nitrate depletion has no effect on the development of mammography films.