Nuclear Associates 07-706
Patient Phantom/Penetrometer System
March 2005
Manual No. 07-706-1 Rev. 2
©2004, 2005 Fluke Corporation, All rights reserved. Printed in U.S.A.
All product names are trademarks of their respective companies
Users Manual
Fluke Biomedical
Radiation Management Services
6045 Cochran Road
Cleveland, Ohio 44139
440.498.2564
www.flukebiomedical.com/rms
Table of Contents
Section 1: General Information................................................................................... 1-1
1.1 Introduction .................................................................................................. 1-1
i
(Blank page)
Introduction
Operators Manual
1
Section 1
Introduction
1.1 Introduction
The U.S. Department of Health, Education and Welfare have published standards of performance for
diagnostic x-ray systems, and most state and local agencies will probably follow the same guidelines.
The Code of Federal Regulations, Title 21, Subchapter J*, Part 1020, includes the following sections:
Entrance Exposure Rate Limits
1020.32 (d-1) Equipment with Automatic Exposure Rate Control
Fluoroscopic equipment, which is provided with automatic exposure rate control, shall not be operable at
any combination of tube potential and current which will result in an exposure rate in excess of 10 R/min
at the point where the center of the useful beam enters the patient.
1020.32 (d-2) Equipment without Automatic Exposure Rate Control
Fluoroscopic equipment, which is not provided with automatic exposure rate control, shall not be operable
at any combination of tube potential and current which will result in an exposure rate in excess of 5 R/min
at the point where the center of the useful beam enters the patient.
1020.32 (d-3)
(i) If the source is below the table, the exposure rate shall be measured 1 cm above the tabletop or
cradle.
(ii) If the source is above the table, the exposure rate shall be measured at 30 cm above the tabletop,
with the end of the beam-limiting device or spacer positioned as close as possible to the point of
measurement.
(iii) In a C-arm type of fluoroscope, the exposure rate shall be measured 30 cm from the input surface
of the fluoroscopic imaging assembly.
*Copies of the regulations are available from:
Bureau of Radiological Health, Food and Drug
Administration, 12720 Twinbrook Parkway,
Rockville, MD 20852.
Use of the Patient Phantom/Penetrometer in a
basic QA program is described in the AAPM Report
No. 4, “Basic Quality Assurance in Diagnostic
Radiology,” which is available from the American
Association of Physicists in Medicine, 111 East
Wacker Drive, Chicago, IL 60601.
NOTE
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Nuclear Associates 07-706
Operators Manual
Measuring the Patient Entrance Exposure Rate in Image-Intensified Fluoroscopic
Equipment
Equipment
07-706 Patient Phantom/Penetrometer
06-526 “Rad-Check Plus” X-Ray Exposure Meter
07-707 Stop Watch (or equivalent)
Figure 1-1
Procedure for Maximum Exposure Rate
A. Source Under Table
1. Position the “Rad-Check Plus” (detector side down) on the x-ray table so its sensitive volume is in
the center of the x-ray field. This is best done by viewing the fluoroscopic image of the “RadCheck Plus” and moving it or the x-ray tube as necessary. The detector presents a circular
shape in the fluoroscopic image. When properly centered, lock the tube carriage and mark the
position of the “Rad-Check Plus” on the table.
2. Place the Patient Phantom/Penetrometer (2 blue blocks plus lead block) on the “Rad-Check Plus”
(see Figure 1-2). Collimate the beam so it does not extend beyond the edges of the phantom.
Lower the image tube intensifier to its lowest height (but not less than 30 cm from the tabletop).
1-2
Introduction
Introduction
Figure 1-2
3. Turn on the “Rad-Check Plus” and press the “Reset” button. Set the fluoroscopic controls to
maximum, with the automatic brightness control on. Activate the controls for 10 seconds, and
multiply the “Rad-Check Plus” reading by 6 to obtain the tabletop exposure in R/min. Use a
stopwatch since the clock supplied with most fluoroscopes is usually not accurate for less than
one minute. The resulting exposure rate represents the maximum tabletop output for equipment
operating in the automatic brightness mode.
4. To determine the patient exposure rate for an adult abdomen, use the two aluminum blocks only.
For a child (about 13 cm tissue thickness) or an adult chest, repeat steps 1 to 3 with the top blue
block removed.
5. By repeating this procedure for various voltage brightness settings and the cine controls
(frames/sec), one can determine the patient exposure rate for a variety of operating conditions.
To find the maximum recommended exposure rate, see Table 2 (taken from National Council on
Radiation Protection Report No. 33). *
NOTE
*The National Council on Radiation Protection and
Measurements consists of recognized authorities
acting in the public interest. In liaison with other
national and international organizations, the
N.C.R.P. collects, analyzes, develops and
disseminates information and recommendations on
the many facets of radiation protection. Available
from N.C.R.P. Publications, P.O. Box 4867,
Washington, DC 20008.
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Nuclear Associates 07-706
Operators Manual
B. Source Over the Table
1. To obtain the entrance exposure for fluoroscopes that use overhead x-ray tubes, raise the
phantom 30 cm above the tabletop, using the long legs (Figure 1-1). Place the “Rad-Check Plus”
on the phantom to obtain the exposure rate at the position where the beam enters the patient.
2. Follow the same procedure as in steps 3, 4, and 5 of Section A.
Consists of 4 metal plates.
(a) Two 7” x 7” x ¾” blocks of high-purity aluminum, which represent the equivalent absorption of
26 cms of water and simulate a thick or heavy-set patient at 90 kVp. A single block is the
equivalent of a child or adult chest. Aluminum simulates the scatter characteristics of the
human body.
(b) One 7” x 7” x 1/8” lead beam-stop plate. When placed in the beam, this plate allows
automatic brightness-control machines to deliver maximum output.
A 7” x 7” x 1/32” thick aluminum penetrometer plate with ¼”, 0.176”, 1/8”, 0.088” and 1/16” holes are
provided. The area of each hole is twice the area of the next smaller one. Place this plate between the
two aluminum blocks to ascertain the contrast gradient of the penetrometer on the image-amplified
systems.
Size 7” x 7” x 1 7/8” high (17.8 cm x 4.7 cm)
Net 9 ½ lbs (4.3 kg)
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Introduction
Introduction
Table 2 Effect of Tube Potential, Distance and Filtration on Air Exposure Rate at Panel of
Fluoroscopes*
1
Source to
Potential
kVp
Panel
Distance
cm inches
30 12
70
38 15
46 18
30 12
80
38 15
46 18
30 12
90
38 15
46 18
30 12
100
38 15
46 18
30 12
110
38 15
46 18
30 12
120
130
140
150
* Typical exposure rates produced by equipment with medium length cables, derived from references (8) and (14)
by interpolation and extrapolation. Filtration includes that of the tabletop and the x-ray tube with its inherent and
added filter. As used above, panel means either panel or tabletop.
38 15
46 18
38 15
46 18
38 15
46 18
38 15
46 18
Equivalent Total Aluminum Filtration
1 mm 2 mm 2.5 mm 3 mm 4 mm
Roentgens per Milliampere Minute
5.3 2.7 2.2* 1.8 1.3
3.5 1.7 1.4† 1.2 0.8
2.4 1.2 1.0 0.8 0.6
7.0 3.9 3.2* 2.6 2.0
4.6 2.5 2.1† 1.7 1.3
3.2 1.8 1.4 1.2 0.9
9.0 5.2 4.3* 3.6 2.8
5.8 3.3 2.8† 2.3 1.8
4.0 2.3 1.9 1.6 1.2
11.0 6.6 5.5* 4.7 3.7
7.0 4.2 3.5† 3.0 2.3
4.9 2.9 2.5 2.1 1.6
13.1 8.0 6.8* 5.9 4.6
8.4 5.1 4.4† 3.8 3.0
5.8 3.5 3.0 2.6 2.0
14.7 9.3 8.0* 7.0 5.5
9.5 6.0 5.1† 4.5 3.6
6.5 4.1 3.6 3.1 2.5
-- 6.8 5.9
-- 4.7 4.1 3.6 2.9
-- 7.6 6.6
-- 5.3 4.6 4.1 3.3
-- 8.5 7.5
-- 5.8 5.2 4.6 3.7
†
5.2 4.2
†
5.9 4.8
†
6.7 5.4
Section 3.1.2(a) When the fluoroscope is operated at 80 kVp, the exposure rate in air at the position
where the beam enters the patient shall not exceed 3.2 R/mA-min at 30 cm and should not exceed 2.1
R/mA-min at 38 cm. For other tube potentials, the exposure per unit charge shall not exceed the values
marked with an asterisk (*) or a dagger (
†).
1-5
Fluke Biomedical
Radiation Management Services
6045 Cochran Road
Cleveland, Ohio 44139
440.498.2564
www.flukebiomedical.com/rms
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