15-13
Radiation Environment Survey
G990710 30 June 2008
Dose Profile
The dose profile was measured using ThermoLuminescent
Dosimeters (TLD) placed at 2cm intervals vertically in the central
column of the acrylic head phantom used for CTDI measurements,
starting at the bottom position. The TLD chips were 3mm x 3mm x
1mm thick in size and purchased from Global Dosimetry, Irvine,
California. 2cm acrylic plugs were placed between the TLDs to
space the TLDs and fill the space. The profile was measured for both
Landscape (D 8.5 - H 8.5) and Half-Beam (D 14 - H 8.5) scans for
standard scans of 8.9s. The TLDs were measured and the doses in
mrem were converted to µSv. The results are presented in the figure
and table below.
Scan Mode and Beam Size
CTDI
w
mGy
CTDI
Free air
mGy
EDS
14 x 8.5 cm
4.72 10.10
14 x 6 cm (maxilla)
6.38 9.76
14 x 6 cm (mandible)
6.35 9.88
Landscape
8.5 x 8.5 cm
5.58 14.01
8.5 x 6 cm (maxilla)
7.56 13.20
8.5 x 6 cm (mandible)
7.51 13.20
To Next Page
Loading...
