Therefore, digital
radiography systems require a special quality control phantom.
The Digital and Conventional Chest Radiography Phantom was developed in response
to the need for objective testing of digital image quality in clinical
radiographs. It will provide quantitative measurements for an evaluation of
image quality and performance of the complete integrated digital system.
The Digital and
Conventional Chest Radiography Phantom is unique in that it yields an image that
is similar enough to an actual chest radiograph to cause the imaging system to
respond normally (i.e., as if the system were processing a true chest image).
It also contains image components that can be visually evaluated to provide a
quantitative assessment of clinical image quality.
Results of
validation tests of the phantom show it to be useful in:
The
QC Phantom for Digital and Conventional Chest Radiography Ensures Consistency
in:
Phantom
Construction
The phantom is constructed
from sheets of copper and aluminum shapes resembling frontal
radiographic projections of human thoracic structures (lungs, heart, ribs,
abdomen, etc).
The components are oriented
and arranged to simulate a projection of a complete thorax, and are then
sandwiched between additional sheets of aluminum and acrylic. The top two
corners of the phantom form “shoulders,” which provide a region for direct x-ray
exposure of the image receptor. This phantom is of rugged construction and
features a handle for easy transport.
Specifications:
Regional Test
Objects are incorporated into the chest
phantom for quantitative image quality assessment in the lung-, heart-, and
subdiaphragm- equivalent image areas. Each test object contains a defined site
for measurement of optical density and a matrix of low-contrast objects for
contrast detail assessment. The phantom is designed such that no irregular
structures (e.g. rigs or wire mesh) obscure the regional test sites.
Contrast
Detail Test Pattern:
The contrast detail
test pattern in each regional test object is comprised of a 5 by 5 matrix of
copper disks of decreasing size and thickness. The copper disks in each column
of the matrix, are of uniform thickness and decreasing size, ranging from 6mm to
0.5 mm in diameter. In each same-size row of the matrix, the copper disks vary
in thickness, with the range of thicknesses selected appropriately for each of
the three chest regions, to yield radiographic contrast spanning the perceptible
range in each region.
Line Pair
Test Pattern: (0.1 mm-thick lead-foil)
This component is included in the lung-equivalent region for assessment of
spatial resolution. The line pairs are oriented diagonally in the phantom to
avoid coincidence with the raster lines in the acquired and displayed images.
Line Spacing (inLP/mm): 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 3.0, 4.0, 5.0.
Stainless
Steel Wire Mesh:
(0.4 mm thick; 8
wires/cm overlays the entire chest area except at the regional test object
sites.
Dimensions: 17” L X 14” W
X 2.5” Thick (43cm X 36cm X 6 cm)
Weight: 30 lbs (13.6 kg)
Item Number: 07-646
Optional Case: 07-646C Wheeled case
with protective inner foam,
and telescoping handle
