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MINISTRY OF HEALTH AND SOCIAL SERVICES

Ministry of Health and Social ServicesP/ BAG 13198Ministerial BuildingHarvey StreetWindhoek 9000.Namibia

Tel: + 264 (61) 2032417Fax: 264 (61) 230 424

E-mail: [email protected]: aebofnamibia.org

NATIONAL RADIATION PROTECTION AUTHORITYCODE: DIAGNOSTIC X-RAY IMAGING SYSTEMS

QUALITY CONTROL

REPUBLIC OF NAMIBIANATIONAL RADIATION PROTECTION AUTHORITYCODE: DIAGNOSTIC X-RAY IMAGING SYSTEMS

QUALITY CONTROL

REPUBLIC OF NAMIBIANATIONAL RADIATION PROTECTION AUTHORITY

CODE: DIAGNOSTIC X-RAY IMAGING SYSTEMS QUALITY CONTROL

DIAGNOSTIC X-RAY IMAGING SYSTEMS QUALITY CONTROL

Table of Contents

1. Introduction.................................................................................................................................... 1

2. GENERAL REQUIREMENTS.............................................................................................................. 2

2. TABLE 1 INDIVIDUAL EQUIPMENT RECORD (IER).......................................................................... 3

3. Table 2: Quality control tests.......................................................................................................... 4

3.1 General tests.................................................................................................................................. 4

3.2 X-ray Tubes and Generators............................................................................................................ 4

3.3 Fluoroscopy Equipment.................................................................................................................. 6

3.4 Computed Tomography................................................................................................................... 7

3.5 Mammography Screen film........................................................................................................... 8

3.6 Mammography Digital.................................................................................................................... 11

3.7 Processor Monitoring..................................................................................................................... 14

3.8 Intensifying Screens and Darkroom................................................................................................ 14

3.9 Dental Radiography......................................................................................................................... 15

4. Table 3: HVL values......................................................................................................................... 16

5. REFERENCES.................................................................................................................................... 17

DIAGNOSTIC X-RAY IMAGING SYSTEMS QUALITY CONTROL1

1. Introduction

X-ray technology has developed extensively over the years with remarkable improvement in the quality of imaging, mainly due to improved technological adaptations. We must remain vigilant of our role as health care provider and the principles of primary health care. In the framework of imaging technology we are endeavouring to provide quality health care services through diagnostic imagining techniques while we should also be mindful to keep the deleterious effect to a minimum. At the centre of this approach is the concept of optimisation which is to derive maximum benefit from the technology while also keeping the potential harm to the minimum possible, taking into account economy, and social factors. Therefore any dose to any patient must be the minimum possible without compromising to achieve the desire diagnostic information. There are two parameters that are necessary to be optimised in order to achieve this objective.

The operator must have the competency to use the equipment, positions the patient, select the most appropriate parameters, deliver the exposure and process the image in a most effective and efficient manner to ensure that the patient derives maximum benefit from the service. The operator must also be equipped to monitor and observe discrepancies that may arise if the equipment is not performing optimally. Therefore the authority considers an important aspect that operators have the educational qualifications, experiences and skills to perform diagnostic imaging and shall continue to develop the means to equip them in terms of optimisation of protection.

The second parameter is that of the equipment which must conform to international standards and provide the optimal output necessary to obtain the desired diagnostic information. This output is dependent on a number of parameters such as the ma, Mas, kv, etc. These parameters must remain within recommended tolerance performance to ensure that the output remains constant and optimal. It is for this reason that this document is issues to all stakeholders to ensure that at all times during operation, after installation and maintenance that the tolerance levels are achieved and maintained.

In the context of the above I wish to re-iterate that the purpose of protecting the patient is to ensure that the radiation exposure remains low as reasonably achievable without compromising of the beneficial diagnostic information of the investigation. It is particularly the stochastic effect that we have in mind when we emphasis this concept. The immediate benefit should not be at the expenses of causing other major health effects later in life and thereby placing an extra burden on our health care system.

I trust that this document shall serve the purpose, for which it was formulated, especially by the manufacturers, suppliers, maintenance engineers and other professional who have a direct influence in the operation of devices that are used for patient exposures.

DIAGNOSTIC X-RAY IMAGING SYSTEMS QUALITY CONTROL 2

2. GENERAL REQUIREMENTS

THE LICENCE HOLDER SHALL:

1. Display the product licence number of equipment.

2. Compile an Individual Equipment Record (IER) containing the information as listed in table1 (column 2)

a. IER is for example a ring binder containing all the information as prescribed in table 1 for each piece of

equipment.

3. Perform the prescribed Acceptance- and Quality Control (QC) tests listed in this document

4. Acquire the relevant quality control manuals or compile in-house written protocols, which describe each

test step by step to ensure that QC tests listed in this document are correctly performed.

5. Ensure that radiographers that perform routine tests listed in the document are competent to execute

the tests.

6. Ensure that the required acceptance tests are performed before the diagnostic x-ray equipment is

put into clinical service when: Acquired or substantially upgraded. Acceptance tests are the initial tests

performed directly after installation and before the equipment is being put into clinical service. Acceptance

tests have three purposes, namely:

a. To ensure that the unit meets stated specifications,

b. To establish baseline parameters for the future quality control program,

c. And To familiarize the customer with operation of the unit.

7. Ensure that all the quality control tests are performed at the prescribed frequencies as listed.

QC tests may be performed more frequently than specified, influenced by the age, stability, make, model,

etc., of the equipment.

8. Ensure that image display monitors and reporting monitors comply with the requirements in this

document.

9. Establish a program to ensure that the radiation dose administered to a patient for diagnostic purposes is

optimised.


2.1 TABLE 1 INDIVIDUAL EQUIPMENT RECORD (IER)

General Radiography Equipment

Proccessor & Hard copy

device

CR Reader

DDR System

Film Viewer

Reporting Monitor

Fluoroscopy Equipment

Computed Tomography Equipment

Mammography equipment

a) Unit-make, model and serial number

x x x x x x x

b) Generator-make, model and serial number

x x x x

c) Product license number, date of the latest license

x x x x

d) Date of installation

x x x x x x x x x

e) Operators manual- (indication that the operator’s manual is available and reference where it is kept

x x x x x x x

f) Results of acceptance tests

x x x x x x x x

g) Results of routine quality control tests

x x x x x x x x x

h) Date of tube replacement

x x x x

i) Details of repairs/maintenance and/or modifications

x x x x x x x x x

j) Details of the company that perform the test(s)

x x x x x x x x

• Please note: for new equipment acceptance tests is the responsibility of the company that installed the equipment.

The x in each cell for each category of equipment indicates which information must be available in the IER.


3.Table 2: Quality control testsPhysical parameter (required test)

Frequency Acceptance Standard

Responsible person

References

3.1 General tests

3.1.1 Safety of premises

On acceptance & and when the workload increase or technique factors change that may jeopardise premises safety

Controlled areas ≤ 5mSv/year, for uncontrolled areas ≤ 1mSv/year

NRPA inspectors

3.1.2 Indicators, mechanical and other safety checks & warm-up

On acceptance & Daily

Results must be documented at least once every 3 months

Radiographer/RSO

3.1.3 Gonad shields, lead rubber aprons and gloves

3 monthly Available and free from holes or cracks (Visual check and if suspect perform an x-ray test)

Radiographer/RSO

Ref 2, 12

2.1.4 Appropriate technique chart displayed at x-ray

6 monthly unit Available, applicable and compliant with ALARA principle

Radiographer/RSO

Ref 11

3.2 X-ray Tubes and Generators

3.2.1 Accuracy of the source (focal spot)-to-image distance (SID) indicators

On acceptance & 12 monthly

The difference between the indicated focus to film distance (FFD) and the actual FFD must be ≤ 2%

Medical physicist/ Qualified service provider

Ref 2, 12


3.2.2 Brightness of the light field, which defines the x-ray field


Average illuminance must be ≥ 100 lux at 100 centimetres or at the maximum FFD, whichever is less


Ref 2, 12

3.2.3 Alignment of the centre of the X-ray field and the centre of the bucky


Deviation must be ≤ ±1 cm @1m


Ref 2, 12

3.2.4 The X-ray field dimensions in the plane of the image receptor must correspond with those indicated by the beam-limiting device

On acceptance &12 monthly

Deviation must be ≤ ±1 cm @1m SID


Ref 2, 12

3.2.5 Congruence between the X-ray field and light field


For any one side deviation must be ≤ ±1 cm isalignment @1 m SID

Radiographer/RSO

Ref 2, 12

3.2.6 Radiation output: reproducibility


Baseline ± 10% Medical physicist/ Qualified service provider

Ref 2, 12

3.2.7 The accuracy of the timer for different settings


Manufacturers’ specifications for specific model or if not available ≤ 5 %


Ref 2, 12

3.2.8 The accuracy of the kV for different settings


Manufacturers’ specifications for specific model or if not available ≤ 5%


Ref 2, 12

3.2.9 Beam quality( (half value layer (HVL)

On acceptance & and annually

Limiting values are shown in table 3


Ref 2, 12

3.2.10 Leakage radiation from the diagnostic source assembly (x-ray tube)

At acceptance and annually

< 1 mGy in 1 hour at 1 m from the focus


Ref 2, 12


3.3 Fluoroscopy Equipment (in addition to tests in no 3.2)3.3.1 Display monitor

set–up On acceptance & 12 monthly

All steps visible and black/white circles using the SMEPT pattern test


Ref 13

3.3.2 Minimum requirements for monitors


Comply with manufacturers recommendation


Ref 13

3.3.3 Field limitation requirement X-Ray field/Image intensifier


The ratio of the areas ≤ 1.15


Ref 13

3.3.4 Dose rate at entrance surface of phantom (Skin dose)


≤ 50 mGy/min (entrance air kerma) and baseline ± 25% or manufacturers specification


Ref 13

3.3.5 Entrance exposure rate to image intensifier


Baseline ± 25% of manufacturers specification


Ref 13

3.3.6 Dose rate reproducibility ( under automatic exposure control )

On acceptance & annually

manufacturers specification


Ref 13

3.3.7 Radiation warning light at entrance, excluding theatres


Must work when beam is activated

Radiographer

3.3.8 Check of Dose area product meter (DAP/KAP meter) or the device that provides a dose read-out during fluoroscopy (total dose)


DAP/KAP meter or dose read out device according to manufacturer’s specifications

Medical physicist/ Service provider

Ref 4

3.3.9 Overall Image quality


Manufacturer’s specifications for a specific model

Medical Physicist/ Service provider

Ref 13


3.4 Computed Tomography3.4.1 Image noise On acceptance

& 12 monthly Baseline ± 10% Inter –slice variation; Mean ± 10%

Medical Physicist/ Service Provider

Ref 12

3.4.2 CT number values


Water baseline ± 5 HU Other materials: baseline ± 10HU


Ref 12

3.4.3 CT number uniformity


Head phantom: ≤±10HU Body phantom: ≤±20HU


Ref 12

3.4.4 Laser Alignment On acceptance & 12 monthly

Allowed misalignment ± 1mm

Radiographer/RSO Ref 12

3.4.5 Couch travel On acceptance & 12 monthly

Allowed misalignment ± 1mm


3.4.6 High contrast spatial resolution


Baseline ±20% Medical Physicist/ Service Provider

Ref 12

3.4.7 Computed tomography dose index (CTDI)


Baseline ±15% Medical Physicist/ Service Provider

Ref 12

3.4.8 Image slice thickness


Baseline ±20% or ± 1mm, whichever is greater


Ref 12

3.4.9 CTDIvol for single slice or rotation

On acceptance & 3 yearly

≤ Reference dose - table 3 of reference 1.2


Ref 12

3.4.10 CT warm up test Daily manufacturers specification

Radiographer Ref 12

3.4.11 Indicators, radiation warning light at entrance, mechanical and other safety checks


Must work properly Radiographer/RSO Ref 12


3.5 Mammography Screen film3.5.1 Image quality

evaluation (phantom images)

1 monthly or weekly

At a minimum, the 4 largest fibers, the 3 largest speck groups, and the 3 largest masses must be visible.

The background optical density must be at least 1.4 and the density difference should be at least 0.4 for a 4-mm thick acrylic disk.

Medical Physicist/ Radiographer

Ref 5, 9

3.5.2 Compression (force and alignment)

On acceptance & annually

manufacturers specification Radiographer/ RSO

Ref 5

3.5.3 Repeat and reject analysis

3 monthly May not increase with more than 2% from the previous determined rate and total rate shall not exceed 5%

Radiographer/RSO

Ref 5

3.5.4 Appropriate exposure technique chart (automatic and manual exposures) displayed near the control panel of the unit

6 monthly Available and applicable Radiographer/RSO

Ref 11

3.5.5 Analysis of fixer retention in film

6 monthly The residual fixer retention shall be ≤ 5 micrograms per square cm

Radiographer/RSO

Ref 5, 9

3.5.6 Assessment of locks, detents, angulations indicators, and mechanical support devices for X-ray tube and image receptor holder assembly


Must function properly Medical Physicist/ Service Provider

Ref 5, 9

3.5.7 Collimation assessment: Deviation between X-ray field and light field


The sum of left plus right edge deviations or anterior plus chest edge deviations must be ≤ 2% of SID


Ref 5, 9

3.5.8 Collimation assessment: Deviation between X-ray field and edges of the image receptor


The X-ray field may not exceed the image receptor at any side by more than 2% of SID and the X-ray field may not fall within the image receptor on the chest wall side


Ref 5, 9


3.5.9 Collimation assessment: Alignment of chest-wall edges of compression paddle and film


The chest-wall edge of the compression paddle may not fall within the image receptor or project beyond the chest-wall edge of the image receptor by more than 1% of SID


Ref 5, 9

3.5.10 Evaluation of system resolution


The resolution with the bars parallel to the anode-cathode axis must be ≥ 13 line–pairs/mm or with the bars perpendicular to the anode-cathode axis must be ≥ 11 line–pairs/mm


Ref 5, 9

3.5.11

Automatic exposure control (AEC) : system performance


Equipment sold prior to 01/01/2003:

The AEC system must maintain the film optical density within ±0.3 of the mean when the thickness of the phantom is varied over 2-6 cm and the kVp is varied over the range of those used clinically for these thickness. If this requirement cannot be met, a technique chart shall be developed showing appropriate techniques (kVp and density control settings) for different breast thickness and compositions that must be used so that optical densities within±0.3 of the average can be produced under photo timed conditions.

Equipment sold after 01/01/2003: The AEC system must maintain the film optical density within ±0.15 of the mean when the thickness of the phantom is varied over 2-6 cm and the kVp is varied over the range of those used clinically for these thickness.


Ref 5, 9


3.5.12 Automatic exposure control (AEC) system performance: Density control


Each step (density setting) shall result in a 12-15% change in mAs, or approximately a 0.15 change in film optical density


Ref 5, 9

3.5.13 AEC reproducibility On acceptance & 12 monthly

The coefficient of variation for R (exposure) or mAs must be ≤ 0.05


Ref 5, 9

3.5.14 Artefact evaluation On acceptance & 12 monthly

No significant artefacts must be visible

Radiographer/RSO

Ref 5, 9

3.5.15 kVp accuracy and reproducibility


The mean kVp may not differ from the nominal kVp (set value) with more than ±5%, or the coefficient of variation may not exceed 0.02


Ref 5, 9

3.5.16 Beam quality (HVL) measurement


The measured HVL must be ≥ kVp/100 (mm Al) (Please note 0.03 must be added when filtration is performed with compression paddle


Ref 5, 9

3.5.17 Average glandular dose


The dose must be ≤ 300 mRad (3 mGy) for 4.2 cm effective breast thickness

Medical Physicist/ NRPA

Ref 5, 9

3.5.18 View box luminance, room illuminance and masking


Luminance of the view box shall be ≥ 3000 cd/m2 and iluminance of the room shall be ≤ 50 lux Viewboxes must be masked to the exposed area of the film

Radiographer/RSO

Ref 5, 9


3.6 Mammography Digital 3.6.1 Repeat and

reject analysis 3 monthly May not increase with more

than 2% from the previous determined rate and total rate shall not exceed 5%


3.6.2 AEC device: Long term reproducibility


Variation of SNR in the reference ROI and dose < ± 10%.


Ref 5

3.6.3 Image receptor homogeneity

On acceptance & 12 monthly Weekly ≤ ± 10%

Variation in mean pixel value < ± 15% (on images); Maximum deviation in SNR < ± 15% of mean SNR (on images); Maximum variation of the mean SNR between weekly images ≤± 10% (between images); Entrance surface air kerma OR tube loading (mAs) between monthly images


3.6.4 Image quality evaluation (phantom images )

12 monthly At a minimum, the 5 largest fibers, the 4 largest speck groups, and the 4 largest masses must be visible. The background optical density must be at least 1.4 for hard copy.

Medical Physicist/ Radiographer

Ref 5

3.6.5 Assessment of locks, detents, angulations indicators, and mechanical support devices for X-ray tube and image receptor holder assembly


Items that are hazardous, inoperative or fail to operate correctly should be repaired by the appropriate equipment manufacturer.


Ref 5

3.6.6 X-ray source: Source-to-image distance – Only if adjustable


Manufacturers specification, typical 600-650 mm


Ref 5

3.6.7 X-ray source: Alignment of X-ray field/image receptor


All sides: X-rays must cover the film by no more than 5 mm outside the film. On chest wall edge: distance between film edge and edge of the bucky must be ≤ 5 mm.


Ref 5


3.6.8 X-ray source: Radiation leakage

On acceptance and after intervention on the tube housing.

≤ 1 mGy in 1 hour at 1 m from the focus


Ref 5

3.6.9 X-ray source: Tube output


>30 µGy/mAs at 1 metre and > 70% of value at acceptance


Ref 5

3.6.10 Tube voltage reproducibility and accuracy


Accuracy for the range of clinically used tube voltages: < ± 1 kV


Ref 5

3.6.11 Half Value Layer (HVL)

On acceptance and after intervention on the tube

For 28 kV Mo/Mo the HVL must be over 0.30 mm Al equivalent


Ref 5

3.6.12 AEC-system: Optical density control setting: central value and difference per step (if applicable)


5 - 15% increase in exposure per step


Ref 5

3.6.13 AEC-system: Short term reproducibility


< ± 5% Medical Physicist/ Service Provider

Ref 5

3.6.14 AEC-system: Object thickness and tube voltage compensation


Thickness indicator < ± 0.5 cm and density < ± 0.15 OD.


Ref 5

3.6.15 Compression force


130 - 200 N (13-20 kg) maintained unchanged for at least 1 minute and indicated compression force should be within ± 20 N of the measured value

Radiographer/RSO Ref 5, 12

3.6.16 Compression plate alignment


≤ 5 mm Radiographer/RSO Ref 5, 12

3.6.17 Grid system factor (if present)

On acceptance, or if faulty

Manufacturer’s specification, typical value < 3.


Ref 5

3.6.18 Grid imaging On acceptance & 12 monthly

No significant non uniformity Medical Physicist/ Service Provider

Ref 5

3.6.19 Image receptor response function


R2 > 0.99, results at acceptance are used as reference


Ref 5

3.6.20 Image receptor Noise evaluation


Results at acceptance are used as reference


Ref 5


3.6.21 Missed tissue at chest wall side

On acceptance Width of missed tissue at chest wall side ≤ 5 mm


Ref 5

3.6.22 Image receptor homogeneity and Image receptor detector element failure (DR systems)


Variation in mean pixel value < ± 15% (on images); Maximum deviation in SNR < ± 15% of mean SNR (on images); Maximum variation of the mean SNR between weekly images ≤± 10% (between images); Entrance surface air kerma OR tube loading (mAs) between annual images ≤ ± 10% .Limits of the manufacturer


Ref 5

3.6.23 Inter plate sensitivity variations (CR systems)


SNR variation ≤ ± 15%. Variation in entrance surface air kerma OR tube loading (mAs)≤± 10%.


Ref 5

3.6.24 Influence of other sources of radiation (CR)

On acceptance The coins should not be visible.


Ref 5

3.6.25 Fading of latent image (CR)

On acceptance Results at acceptance are used as reference.

Ref 5

3.6.26 Dosimetry On acceptance & 12 monthly

< 2.5 mGy for 4.5 cm PMMA Medical Physicist/ Service Provider

Ref 5, 12

3.6.27 Threshold contrast visibility (use contrast line pair test)


manufacturers specification Medical Physicist/ Service Provider

Ref 5

3.6.28 Exposure time On acceptance & 12 monthly

manufacturers specification Medical Physicist/ Service Provider

Ref 5

3.6.29 Geometric distortion and artefact evaluation


No disturbing artefacts, no visible distortion.


Ref 5

3.6.30 Ghost image/erasure thoroughness


“Ghost image”-factor < 0.3 Medical Physicist/ Service Provider

Ref 5

3.6.31 Monitors : Ambient light


< 10 lux or manufacturers specification


Ref 5

3.6.32 Monitors: Resolution


All line patterns should be discernible.

Medical Physicist/ service Provider

Ref 5

3.6.33 Monitors: Luminance range: Maximum to minimum luminance ratio


Primary display devices ≥ 250 Secondary display devices ≥ 100; Displays belonging to one displaying station should not exceed 5% of the lowest


Ref 5


3.6.34 Monitors: Greyscale Display Function


<± 10% of the GSDF for primary class displays and <± 20% of the GSDF for secondary class displays (default test pattern to be used)


Ref 5

3.6.35 Monitors: Luminance uniformity


Maximum luminance deviation of a display device should be less than 30% for CRT displays and LCD displays ((Lmax-Lmin)/Lcentre < 0.3).


Ref 5

3.6.37 Monitors: Density uniformity


Maximum optical density deviation should be less than 10% ((Dmax -Dmin)/Dcentre < 0.1)

SMEPT pattern


Ref 5

3.7 Processor MonitoringTests must be performed before diagnostic films are processed. All measurements must be plotted on graph paper 3.7.1 Processing

temperature Daily Baseline ±1ºC Radiographer Ref 12

3.7.2 Base + Fog (B+F)

Daily Variance ≤ +0.03 OD. Maximum OD < 0.3

Radiographer Ref 12

3.7.3 Mid-density (MD) step (speed index)

Daily Variance ≤ ± 0.15 OD

Radiographer Ref 12

3.7.4 Density difference (DD) (contrast index)

Daily Variance ≤ ± 0.15 OD

Radiographer Ref 12

3.8 Intensifying Screens and Darkroom

3.8.1 Cleanliness of darkroom and screens

Written protocol for maintaining darkroom cleanliness, cassettes and screens clean, free from blemishes

Radiographer Ref 12

3.8.2 Condition of cassettes and screens

12 monthly Screen type, speed and date of installation Identification (cassette no.) and light tightness

Radiographer Ref 12

3.8.3 Darkroom fog Acceptance, 6 monthly & when fault reported

Density difference ≤ 0.05 for 2 minutes

Radiographer Ref 12

3.8.4 Relative speed of intensifying screens

Before initial use & 24 monthly

Baseline minus 10% Radiographer Ref 12


3.9 Dental RadiographyIntral oral, Panaromic and Cephalometric3.9.1 Filtration (HVL) Acceptance and

after equipment service

Table 3 Medical Physicist/ Service Provider

Ref 6, 12

3.9.2 Radiation output repeatability

Acceptance and 24 monthly

The actual peak X-ray tube voltage should not deviate from the indicated or selected value by more than 5%, or by the value specified by the manufacturer. It must not be possible to set or operate the X-ray tube with the tube voltage below 50 kilovolts (peak).


Ref 6, 12

3.9.3 Beam alignment and collimation


The primary radiation beam must be collimated in size at the end of the applicator to a circle not more than 7 cm in diameter


Ref 6,12

3.9.4 Irradiation switch Acceptance and 24 monthly

There must be an irradiation switch to start and terminate X-ray production. This switch must be of a type that requires continuous pressure by the operator to produce X-rays. Where the irradiation switch is a foot switch it must be so constructed that operation of the X-ray tube cannot occur inadvertently should the foot switch be overturned. Where the irradiation switch is mounted at the end of a cable, the cable must be of sufficient length to enable the operator to stand at least 3 metres from the tube housing and the patient. If the switch is in a fixed location, it must be at least 3 metres from the tube housing


Ref 6, 12

3.9.5 Focal spot to skin distance


A position-indicating device must be provided to limit the minimum focal spot to skin distance to not less than 18 cm. The applicator must be an open-ended type. Pointed cone or close-ended applicators must not be used


Ref 6, 12

3.9.6 Exposure timer reproducibility


coefficient of variation ≤5% Medical Physicist/ Service Provider

Ref 6, 12

3.9.7 Exposure timer accuracy


Limit: ≤10 % error for I-O units ≤ 5% error for all other units


Ref 6, 12


3.9.8 X-ray tube leakage

Acceptance At every rating specified by the manufacturer, the air kerma from leakage radiation at a distance of 1 m from the focal spot, averaged over an area not exceeding 100 cm2, does not exceed 1mGy in one hour


Ref 10

3.9.9 Total filtration Acceptance < 2.5 mmAl or less then manufacturers recommendation


Ref 10

3.9.10 Slice thickness Acceptance and 12 monthly

±20% or 1mm (whichever is greater) Medical Physicist/ Service Provider

Ref 10

3.9.11 High contrast spatial resolution


As per manufacturers recommendation


Ref 10

3.9.12 Image uniformity Acceptance and 12 monthly



Ref 10

3.9.13 Radiation output accuracy


The actual peak X-ray tube voltage should not deviate from the indicated or selected value by more than 5%, or by the value specified by the manufacturer

Medical Physicist/ service Provider

Ref 10

3.9.14 Radiation output reproducibility


±5 % Medical Physicist/ Service Provider

Ref 10

3.9.15 Radiation field size


Maximum 2 mm deviation between the light field and the radiation field


Ref 10

3.9.16 Dental cone beam CT: DAP




Ref 10

4. Table 3: HVL values (IAEA Material)X-ray tube voltage (kVp) 71 80 90 100 110 120 130 140 150

Minimum HVL (mmAL) 2.1 2.3 2.5 2.7 3.0 3.2 3.5 3.8 4.1

HALF-VALUE LAYERS for intermediate selected voltages are to be obtained by linear interpolation.DentalX-ray tube voltage (kVp) 60 70 80 2.3 90

Minimum HVL (mmAL) Intra Oral 1.5 1.5 2.3 2.5

Minimum HVL (mmAL) Panaromic and Cephalometric 1.8 2.1 2.3 2.5


5. REFERENCES

1. AAPM report 29, Equipment requirement and quality control for mammography, 1990.

2. AAPM report 74, quality control in Diagnostic Radiology, 2002.

3. Department of health (DOH), Code diagnostic QC, version7, https://sites.google.com/site/

radiationcontroldoh.

4. Dosimetry in Diagnostic Radiology: An international code of practice. IAEA TRS 457.

5. European guidelines for quality assurance in breast cancer screening and diagnosis – fourth edition,

European Communities, 2006,

6. Health Canada’s Recommendations for a quality assurance program in Dental Radiography, sites.google.

com/site/introdentalradiographyi/page

7. IMAGING QUALITY ASSURANCE MANUAL Published by the Radiation Safety Office for the University of

Rochester Medical Center, Revision 1, Dated 3/05, http://extranet.urmc.rochester.edu/radiationSafety/ Î

Forms, Manuals & Posters Î Radiology QA Manual

8. KCARE; Protocols for QA of CR System – Routine and Annual; Protocols for QA of DDR Systems – Routine

and Annual, http://www.kcare.co.uk Î Education Î Protocols, CR system: Commissioning & Annual tests;

CR system: Routine QA tests; DDR system: Commissioning & Annual tests, and DDR system: Routine QA

tests.

9. Quality assurance programme for screen film mammography, IAEA Human Health series No.2, 2009.

10. Recommendation for the design of x-ray facilities and quality assurance in dental cone beam (CT) system,

J Holroyd and A Walker, North Western Physics, HPA-RPD-065

11. Ministry of Health and Social Services, Radiation Protection and Waste Disposal Regulations, 2011.

12. www.rpop.iaea/training material/ Radiation protection in Diagnostic and Interventional Radiology

13. www.IPEM.org.uk (institute of Physics and Engineering in Medicen) Recommended standards for routine

performance testing of diasnostic X-ray imaging systems report 91, 2005

Edition 1

New Creation Printing & Design 2015+264 61 256 294

Ministry of Health & Social Services 1st & 2nd floors Mandume Office ParkCnr Dr W Kults and Teinert StreetHochland ParkWindhoekNamibia

Tel: +264 61 203 2417 Fax: +263 61 230 424

E-mail:[email protected] www.aebofnamibia.org

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DIAGNOSTIC X-RAY IMAGING SYSTEMS QUALITY …aebofnamibia.org/wp-content/uploads/pdf/2016/code_diagnostic_x-ray...3.8 Intensifying Screens and Darkroom ... test step by step to ensure