Precision Photometer

©JRT Associates 2008

• The luminance of view boxes for interpretation or QC of mammography images meets or exceeds minimum levels
• Ambient illuminance levels are below prescribed levels
• Viewing conditions have been optimized
• NIST-traceable
• Performs required ACR (NITS) measurements

Photometers are required for medical, scientific, and laboratory applications. This Precision Photometer utilizes a filtered sensor with spectral response tightly calibrated to the CIE photo pic response. The illuminance receptors closely follow the Cosine Law relative sensitivity versus angle of illuminance.

The Precision Photometer is a highly accurate instrument designed to measure both illuminance (the amount of light falling on a surface) in lux (lumens per m2) and luminance (the amount of light emitted from a surface) in nit (candela per m2).

Key Features

• Easy to read digital display
• Small...convenient to carry and supplied with its own carrying case
• Rugged construction
• Measure button- press it to get continuously updated readings. Releasing the measure button freezes the last reading for convenient reference
• Range button- adjusts the measurement display for the resolution desired
• LED display- visible in very dim light, as well as direct sunlight. LED displays are inherently robust in comparison to liquid crystal displays (LCDs)
• The battery-powered photometer provides tens of thousands of readings

The Precision Photometer easily and quickly verifies that an x-ray collimator light and/or CT system light source used for patient alignment and localization is in accordance with regulations and guidelines. It also measures the brightness and uniformity of an x-ray view box, quickly detecting non-uniformity (which may appear as artifacts, causing misdiagnosis). This battery-operated photometer has a bright LED display and only two operating controls: “Measure” for taking a reading, and “Range” to adjust the meter display to the light level being measured.

07-621 Precision Photometer
07-621-6341 Precision Photometer with rotating illuminance receptor
07-621-6342 Precision Photometer with rigid 1 inch fiber-optic probe
07-621-6343 Precision Photometer with flexible 12 inch fiber-optic probe

89-621 Carrying Case

07-634 Fiber-optic Probe, Flexible 12 inch (must be calibrated with meter)
07-634-1000 Fiber-optic Probe, Rigid 1 inch (must be calibrated with meter)
07-634-1100 Rotating Illuminance Receptor (must be calibrated with meter)

The flexible 12” fiber-optic probe is designed for measuring relative densities of areas on radiographs, or luminance of video screens and view boxes

Frigid 1-inch fiber-optic probe: designed
for readings taken against a monitor
or view box

Rotating illuminance receptor is designed for reading background light and field light