AERB/RSD/MDX/CT/ATR/2009
ACCEPTANCE / PERFORMANCE TEST FOR
COMPUTED TOMOGRAPHY (CT) SCANNER
RADIOLOGICAL SAFETY DIVISION
ATOMIC ENERGY REGULATORY BOARD,
NIYAMAK BHAVAN, ANUSHAKTINAGAR
MUMBAI-400 094
TESTS TO BE CARRIED OUT FOR THE TYPE APPROVAL OF THE COMPUTED
TOMOGRAPHY(CT) SCANNER
PART-I
1.1. Name & Address of the
manufacturer
:
1.2 Name and Address of local
agent/supplier
:
1.3. Name and address of the
institution, where the CT scanner
is tested
:
1.4 Model name of the scanner
:
1.5 Type Approval No.
:
1.6 Features of the scanner
: Conventional / Spiral
Single slice/ Multiple slice
1.7 Tests conducted by
Date:
:
Signature
Name
Designation
Company seal
PART-II
SPECIFICATIONS & TECHNICAL DETAILS OF THE SCANNER
A.
X-RAY GENERATOR
1. Make & Model
2. Operating potential
:
(kVp)
3. Operating current (mA)
:
4. Mains Requirement
:
5. Generator Capacity (power)
:
6. Scan time per rotation
:
7. Scan time for full helical scan
:
8. Type of rectification
B.
:
: Full wave/ Multi-pulse
X-RAY TUBE
1. Make & model of the tube
:
2. Type of anode/material/angle
: Rotating/Stationary
2. No. of focal spots
: One/ Two
Focal spot dimensions
C.
:
Focus-1
------------- mm
X
----------- mm
Focus-2
------------- mm
X
----------- mm
BEAM COLLIMATION SYSTEM
1. Selectable slice thickness in mm/
Slice acquisition mode
:
2. Pre-patient/post-patient collimator
(collimator width)/(detector width)
3. Fan angle of scan beam
:
D.
:
GANTRY
1. Type of the scan motion
: Rotate-Rotate/ Stationary-Rotate
2. Continuous rotation
: available
(Limits :
)
: not available
3. Rotation mechanism
: slip ring/ other
4. Gantry aperture diameter
: ---------------- cm
5. Gantry tilt (maximum)
Gantry top towards couch
: -------------
Gantry top away from the couch
: -------------
Angular accuracy
:
6. Light-field localizer type
Position of light field localizer
:Laser/focussed light beam
: At scan plane/ external to scan aperture
7. Focus-isocentre distance
:
8. Focus-detector distance
:
9. Maximum Field of View (FOV)
:
10. Bi-way patient communication system
:
E.
PATIENT SCANNING TABLE
1. Maximum movements
(Full out to full in scan table length)
: ---------- cm
Minimum table incrementation available:
-------- mm
Indexing accuracy
:  --------- mm
Minimum table height
:  --------- cm
Maximum table height
: ± --------- cm
2. Location of table position indicators
3.
Gantry
Table
Control console
Scan Image
: Yes/No
: Yes/No
: Yes/No
: Yes/No
Table tilt
: Possible/ Not possible
a. If possible
F.
Head end up
: -------------
Head end down
: -------------
Angulation accuracy
: -------------
DETECTORS
1. Type
: Scintillator/Photodiode
Scintillator/PM tube
Pressurised xenon chamber
Other (specify)
Type of scintillator
2. Number of detectors(Total)
Number of Reference Detectors
Number of Measuring Detectors
Total No. of Detector rows
Number of measuring channels
:
:
:
:
:
:
3. Recommended calibration frequency
Air calibration scans
:
Water calibration scans
:
4. Availability of imaging phantom
:
Yes / No
PART-III
A.
A.1
MECHANICAL TESTS
Alignment of table to gantry
Check the congruence between the gantry midline and table midline using plumb
Line.
Result (Gantry midline to table midline)
Tolerance
A.2
:
:  5 mm
Scan localization light accuracy (use film without screen)
Exposure parameters: kVp :
mAs :
Slice thickness (min) :
Result
:
Alignment error
: Internal laser light :------------ mm
External laser light:------------ mm
Tolerance
A.3.
:  2.0 mm
Gantry tilt
Exposure parameters : kVp :
Result
Actual gantry tilt
:
Measured gantry tilt :
Tolerance
:  30
mAs :
A.4.
Table position /incrementation ( same film can be used for tests A2, A3, and A4)
Initial table position (arbitrary):
Load on couch
:
Exposure parameters : kVp :
mAs :
Slice thickness :
Applied table incrementation :
Table position from reference
position
1cm
2 cm
Expected
Measured
Tolerance
B.
:  2.0 mm
COLLIMATION TEST
B.1.
Radiation Profile Width
Exposure parameters : kVp :
Result :
Applied Slice
thickness (mm)
mAs :
Measured density
profile width (FWHM)
Tolerance :  1.0 mm (without post patient collimator)
C. TESTS ON X-RAY GENERATOR
C.1
Set kV
Measurement of operating potential
Measured kVp
3 cm
4 cm
5 cm
mA station
I
mA station
III
mA station
IV
Ave kVp
:  2 kVp
Tolerance
C.2 4.
mA station
II
Timer Accuracy
Set Time
Observed Time
% Error
Tolerance: Tolerance :  10 %
C.3.
Measurement of mA linearity
Operating parameters : kVp :
Slice thickness :
mA settings
Output in Gy
II
mAs
I
Xmax – Xmin
Coefficient of linearity (COL) = -------------Xmax+ Xmin
Tolerance in COL
:  0.1
Time:
III
Gy/mAs
(X)
C.5
Output Consistency
Operating parameters : mAs :
kVp
1
2
Slice thickness :
Output
3
Mean (X)
4
COV
5
Coefficient of Variation (COV) = X-1 (  [Xi -X ]2/n-1)½
Tolerance in COV
D.1.
:  0.05
Low contrast resolution
Use low contrast resolution test phantom.
Operating parameters : kVp :
mAs :
Window width :
Result :
Slice thickness
Low contrast resolution : ---------- mm at -------- % contrast difference
Tolerance
D.2.
: 5.0 mm at 1% contrast difference (minimum)
2.5 mm at 0.5 % contrast difference (expected)
High contrast resolution
Use high contrast resolution test phantom.
Operating parameters : kVp :
Window width :
mAs :
Slice thickness :
Use high resolution algorithm.
Result :
Size of the smallest resolvable bar/hole pattern : -----------mm (-------- lp/cm)
Tolerance : At 10% contrast difference the size of the bar/hole pattern that could
be resolvable should be 1.6 mm ( 3.12 lp/cm).
Expected high contrast resolution : 0.8 mm (  6.25 lp/cm)
F.
RADIATION DOSE TESTS
F.1.
Measurement of Computed Tomography Dose Index (CTDI)
Use pencil ionization chamber connected to a suitable electrometer or TLD, in
conjunction with a head/body phantom. Measure the dose in the axial and peripheral
cavities of the phantom for typical techniques.
Operating parameters : kVp : 80 / 100 / 140 mAs : 100
Result:
Head
Slice thickness :
Body
Axial dose
: --------- mGy/mAs
-----------mGy/mAs
Peripheral dose
: --------- mGy/mAs
-----------mGy/mAs
: --------- mGy/mAs
-----------mGy/mAs
: ---------mGy/mAs
-----------mGy/mAs
: ---------m Gy/mAs
-----------mGy/mAs
Peripheral dose(Mean): ---------mGy/mAs
-----------mGy/mAs
CTDIc
: --------- mGy/mAs
----------mGy/mAs
CTDIp (mean)
: --------- mGy/mAs
----------mGy/mAs
Weighted CTDI (CTDIw) = 1/3 CTDIc + 2/3 CTDIp
CTDIw
: ----------- mGy/mAs
Tolerance
:  20% of the quoted value (Expected)
 40% of the quoted value (maximum)
G. Radiation leakage levels from X-ray tube housing at 1 M from the focus
Operating Potential:
kV,
mAs:
mA X
Sec
( use maximum kV available in the machine for leakage measurement)
Radiation Leakage Level (mR/hr)
Front(Cathode) Back (Anode)
Max leakage =
Left
Right
--------- mAmin X ----Max leakage mR/hr
60 X -----mA used for measurement
Maximum radiation leakage from tube = ------------- mR in one hour
Result:
Maximum radiation leakage at 1 meter from the focus for workload of 180
mAmin in one hour is
mR.
Recommended upper limit:
Leakage radiation level at 1 meter from the focus should be  115 mR in one hour.
Date:
Tested by:
Signature
Name
Designation
Company
Signature of customer/user
Seal of the institution
Compilation of QA test results of Computed Tomography equipment
Model Name:
Sr.
No.
Parameters tested
Specific
values
1
Alignment of table to
gantry
±5 mm
2
Gantry tilt
±30
3
Table indexing accuracy
(mm)
±2 mm
4
Slice thickness (mm)
±1 mm
5
Accuracy of Operating
Potential (kV)
±2 kV
6
Accuracy of Timer
< 10 %
7
Linearity of tube current
(CoL)
± 0.1
8
Reproducibility of output
(CoV)
CoV < 0.05
9
Radiation dose test
CTDI –( mGy/100 mAs)
at 120 kV
± 20 %
10
Low contrast resolution
5.0 mm at 1%
contrast
11
High contrast resolution
3.12 lp/cm
12
Radiation Leakage level
from X-Ray tube housing
140 kV at 100 mA
< 1mGy in one
hour
Measured values
Tolerance
Remarks
I hereby undertake that all the information provided above is correct and in accordance with the
detailed Quality Assurance report enclosed herewith.
Date:
Tested by:
Signature
Name
Designation
Company
Signature of customer/user
Seal of the institution