GE HEALTHCARE
D
IRECTION 5141177-100, REVISION 14 BRIGHTSPEED ELITE, EDGE, EXCEL: PRE-INSTALLATION
Chapter 4 - Room Planning Page 91
4 – Room Planning
Section 10.0
Radiation Protection
NOTICE Scanner-room shielding requirements should be reviewed by a qualified radiological health
physicist taking into consideration:
• Scatter radiation levels within the scanning room (see Figure 4-23)
• Equipment placement
• Weekly projected work-loads (# patient/day technique (kvp*ma))
• Materials used for construction of walls, floors, ceiling, doors, and windows
• Access to surrounding scan room areas
• Equipment in surrounding scan room areas (e.g., film developer, film storage)
Figure 4-22 depicts measurable radiation levels within the scanning room while scanning a 32 cm
CTDI phantom (body) and a 20 cm water phantom (head) with the technique shown. The mAs, kV
and aperture scaling factors shown in Table 4-11 can be used to adjust exposure levels to the scan
technique used at the site.
Note: Actual measurements can vary. All measurements have an accuracy of ± 20% because of
measurement equipment, technique, and system-to-system variation.
Use the correction factors shown in Table 4-11 to adjust exposure levels to the usual scan
technique at your site.
NOTICE The units of measure used for radiation levels have been changed in this publication, from
mR (millirads) to Gy (micrograys). The conversion factor is:
1 mR = 8.69 Gy
CHANGED PARAMETER MULTIPLICATION FACTOR
mAs new mAs/100
80 kV 0.21
120 kV 0.71
140 kV 1.0
4 x 3.75mm images 0.82
16 x 0.625 LD
8 x 1.25 LD
4 X 2.5 LD
Fluro 5mm
0.59
4 x 1.25 LD
5mm (1i)
Fluro 2.5 mm
0.40
1 x 1.25mm images 0.20
2 x 0.625 LD
1 x 1.25
0.10
Table 4-11 Shielding Requirements Scaling
To Next Page
Loading...
Need help?
General
