Imaging Sciences i-Cat 17-19 - Dose Profile

990400 Rev C 2010 May 1
Radiation Environment Survey
13-9
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. Two cm acrylic plugs were placed between the TLDs to
space the TLDs and fill the space. The profile was measured for both
Diameter 23cm and Diameter 16cm 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.
Acq.
Time
(sec)
Diameter
16 cm
Diameter
23 cm
13 cm 11 cm 10 cm 8 cm
6 cm
maxilla
6 cm
mandible 4 cm 17 cm
CTDI
w
CTDI
Free
air
CTDI
w
CTDI
Free
air
CTDI
w
CTDI
Free
air
CTDI
w
CTDI
Free
air
CTDI
w
CTDI
Free
air
CTDI
w
CTDI
Free
air
CTDI
w
CTDI
Free
air
CTDI
w
CTDI
Free
air
8.9 2 2.5 2.5 3.15 2.5 3.15 2.5 3.15 3.15 4 2.5 2 3.15 4 1 1.25
26.9 4 5 5 6.3 5 6.3 5 6.3 6.3 8 5 4 6.3 8
4.8 1.25 1.25 1.25 1.6 1.25 1.6 1.25 1.6 1.6 2 1.25 1 1.6 2
14.7 2.5 2.5 2.5 3.15 2.5 3.15 2.5 3.15 3.15 4 2.5 2.5 3.15 4