Quality Assurance and Quality Control of Equipment in Diagnostic Radiology Practice-The Ghanaian Experience

The World Health Organization (WHO) defines a quality assurance (QA) programme in diagnostic radiology as an organized effort by the staff operating a facility to ensure that the diagnostic images produced are of sufficiently high quality so that they consistently provide adequate diagnostic information at the lowest possible cost and with the least possible exposure of the patient to radiation: (World Health Organization [WHO], 1982). The nature and extent of this programme will vary with the size and type of the facility, the type of examinations conducted, and other factors. The determination of what constitutes high quality in any QA programme will be made by the diagnostic radiology facility producing the images. The QA programme must cover the entire X-ray system from machine, to processor, to view box. Quality assurance actions include both quality control (QC) techniques and quality administration procedures. QC is normally part of the QA programme and quality control techniques are those techniques used in the monitoring (or testing) and maintenance of the technical elements or components of an X-ray system. The quality control techniques thus are concerned directly with the equipment that can affect the quality of the image i.e. the part of the QA programme that deals with instrumentation and equipment. An X-ray system refers to an assemblage of components for the controlled production of diagnostic images with X-rays. It includes minimally an X-ray high voltage generator, an X-ray control device, a tube-housing assembly, a beam-limiting device and the necessary supporting structures. Other components that function with the system, such as image receptors, image processors, automatic exposure control devices, view boxes and darkrooms, are also parts of the system. The main goal of a QC programme is to ensure the accuracy of the diagnosis or the intervention (optimising the outcome) while minimising the radiation dose to achieve that objective In a typical diagnostic radiology facility, QC procedures may include the following: a. Acceptance test and commissioning Acceptance test is performed on new equipment to demonstrate that it is performing within the manufacturer’s specifications and criteria (and also to confirm that the equipment meets


Introduction
The World Health Organization (WHO) defines a quality assurance (QA) programme in diagnostic radiology as an organized effort by the staff operating a facility to ensure that the diagnostic images produced are of sufficiently high quality so that they consistently provide adequate diagnostic information at the lowest possible cost and with the least possible exposure of the patient to radiation: (World Health Organization [WHO], 1982). The nature and extent of this programme will vary with the size and type of the facility, the type of examinations conducted, and other factors. The determination of what constitutes high quality in any QA programme will be made by the diagnostic radiology facility producing the images. The QA programme must cover the entire X-ray system from machine, to processor, to view box. Quality assurance actions include both quality control (QC) techniques and quality administration procedures. QC is normally part of the QA programme and quality control techniques are those techniques used in the monitoring (or testing) and maintenance of the technical elements or components of an X-ray system. The quality control techniques thus are concerned directly with the equipment that can affect the quality of the image i.e. the part of the QA programme that deals with instrumentation and equipment. An X-ray system refers to an assemblage of components for the controlled production of diagnostic images with X-rays. It includes minimally an X-ray high voltage generator, an X-ray control device, a tube-housing assembly, a beam-limiting device and the necessary supporting structures. Other components that function with the system, such as image receptors, image processors, automatic exposure control devices, view boxes and darkrooms, are also parts of the system. The main goal of a QC programme is to ensure the accuracy of the diagnosis or the intervention (optimising the outcome) while minimising the radiation dose to achieve that objective In a typical diagnostic radiology facility, QC procedures may include the following: a. Acceptance test and commissioning Acceptance test is performed on new equipment to demonstrate that it is performing within the manufacturer's specifications and criteria (and also to confirm that the equipment meets Quality Assurance and Quality Control of Equipment in Diagnostic Radiology Practice -The Ghanaian Experience 293 variations of parameter values, but they may be subjective, e.g. the opinions of professional personnel, in cases where adequate objective standards cannot be adequately defined. These standards should be routinely reviewed and redefined as and when the need arises. 5. Evaluation. The facility quality assurance programme should make provisions for results of monitoring procedures to evaluate the performance of the X-ray system(s) to determine whether corrective actions are needed to adjust the equipment so that the image quality consistently meets the standards for image quality. Additionally, the facility quality assurance programme should also include means for evaluating the effectiveness of the programme itself. 6. Records. The programme should include provisions for the keeping of records on the results of the monitoring techniques, any difficulties detected, the corrective measures applied to these difficulties, and the effectiveness of these measures. Typically, records should contain the following: -Results of the calibration and verification of the measurement instruments, -Results of acceptance and quality control tests, -Patient dosimetry results and comparison with guidance or diagnostic reference levels (DRLs), -Inventory of X-ray systems. 7. Manual A quality assurance manual should be written in a format which permits convenient revision as needed and should be made readily available to all personnel. 8. Education and training. A quality assurance programme should make provisions for adequate training for all personnel with quality assurance responsibilities. The training should be specific to the facility and the equipment in use. 9. Setting up of committee. Large facilities such as teaching or referral or specialist hospitals should consider the establishment of a quality assurance committee whose primary function would be to maintain lines of communication among all groups with quality assurance and/or image production or interpretation responsibilities. The extent to which each of these elements of the quality assurance programme is implemented should be determined by an analysis of the facility's objectives and resources conducted by its qualified staff or by qualified outside consultants. Implementation should also be based on Regulatory requirements (Regulations, Codes or Guides), Health Service Policy as well as the Hospital's Local Rules on the application of ionising radiation. The expected benefits from any additional actions should be evaluated by comparing to the resources required for the programme. Several studies have indicated that many diagnostic radiological facilities produce poor quality images and give unnecessary radiation exposure to patients. Inkoom et al. recommends for the institution of regular assessment of QC parameters that affect patient dose and image quality at diagnostic facilities, since patient protection is an essential element for the overall management of patient undergoing X-ray examination (Inkoom et al., 2009). A QA programme should also address issues of radiation protection in the diagnostic radiology. This will ensure that the image quality of radiographs meet minimum quality criteria for confident diagnosis, patient doses are as low as reasonable achievable (ALARA) and exploration of optimisation options. For instance, the International Basic Safety Standards (BSS) (BSS, 1996) requires Licensee / Registrant to; • establish the Radiation Protection Programme (RPP), • provide the necessary resources to properly apply the RPP, • ensure that the RPP addresses all phases of diagnostic and interventional radiology from purchase, installation, maintenance, qualifications and training of users. etc. and • ensure appropriate protection for patients, staff and members of the public. This paper reviews the current QA programme and QC for diagnostic radiology practice in Ghana. The state of equipment in clinical use, QC measurements that are done, Regulatory Guidelines for QA/QC and what holds for the future are presented.

Equipment used in diagnostic radiology practice in Ghana
The inventory of number of items of diagnostic X-ray equipment in Ghana is compared with Health-care level III category of Zimbabwe (UNSCAER 2008Report, 2010

Advances in technology
The transition of film screen radiography to computed radiography (CR) and digital radiography (DR) is anticipated to increase in Ghana. Currently, DR and CR systems account for about 4% of conventional X-ray machines in Ghana. With the introduction of digital X-ray systems in medical imaging, QC is becoming increasingly more important. One of the reasons is that overexposed detectors, which provided a natural dose limitation for conventional image receptor systems are no longer observed in digital systems (Zoetelief et al., 2008). Also, such new technology brings with it new challenges in terms of its control and quality assurance management.  , 2006). The generators and X-ray tubes that are used in the radiographic systems for both CR and DR remain the same as their film screen system counterparts and QA of the X-ray tube and generators in digital systems follows the standard methods (IPEM, 2005). However, it must be noted that whenever automatic exposure control (AEC) system is selected, the X-ray output is linked (directly or indirectly) to the detector performance and this demands consideration. This can lead to an increase or decrease in patient dose when the X-ray system becomes faulty or changes in the output consistency occurs. The detectors that are currently available in CR and DR have a wide exposure dynamic range which means there is significant potential for the initial setup of such systems not to be optimised (  Another part of the radiographic chain which is often neglected is the performance of monitors. Subjective evaluations of image quality assessment are made at a workstation/review monitor and as such this must be part of the QA programme. In the era of CTs, there has also been a transition from single slice to multi-slice CT and Ghana's first 64 multi-slice CT together with other accessories like cardiac monitor and automatic contrast agent injector has been installed recently. Indications are that the transition from film screen technology to digital technology is expected to be very rapid in Ghana. This calls for reorganisation and re-alignment of current structures by all relevant stakeholders of the diagnostic imaging community so as to face the challenges that this new technology offers.

Regulatory guidelines for quality assurance/quality control measurements
In Ghana, the National Competent Regulatory Authority charged with the responsibility for Authorisation and Inspection of practices using radiation sources and radioactive materials is the Radiation Protection Board (RPB) (Radiation Protection Instrument LI 1559, 1993 promoting human resource development in radiation protection, safety and nuclear security by promoting training of regulatory staff and organising courses for registrants and licensees, • carrying out radiation and waste safety services, and • carrying out relevant research to enhance protection of workers, patients, the public and the environment from the harmful effects of ionising radiation and the safety and security of radiation sources. In exercise of the powers conferred by regulations 8 (2) and 11 (c & e) of the Legislative Instrument LI 1559 of 1993, RPB has issued the following Guides to ensure compliance with the Regulations intended to protect patients, workers and the general public from the risks associated with exposure to ionising radiation in the course of operating a practice in Ghana. In all, it has issued ten Guides which are listed below: 1. Radiation Protection and Safety Guide No. GRPB-G1-Qualificaiton and Certification of Radiation Protection Personnel .

Radiation Protection and Safety Guide No. GRPB-G2-Notificaiton and Authorisation by
Registration or Licensing, . 3. Radiation Protection and Safety Guide No. GRPB-G3-Dose Limits, . 4. Radiation Protection and Safety Guide No. GRPB-G4-Inspection, . 5. Radiation Protection and Safety Guide No. GRPB-G5-Safe Use of X-Rays, (Schandorf et al., 1998). 6. Radiation Protection and Safety Guide No. GRPB-G6-Safe Transport of Radioactive Material, . 7. Radiation Protection and Safety Guide No. GRPB-G7-Enforcement, . 8. Radiation Protection and Safety Guide No. GRPB-G8-Occupational Radiation Protection, . 9. Radiation Protection and Safety Guide No. GRPB-G9-Medical Exposure, . 10. Radiation Protection and Safety Guide No. GRPB-G10-Safe Application of Industrial Radiography, . Currently there are Institutional reforms to establish an independent Regulatory Body to regulate the peaceful uses of nuclear energy which will be known as Ghana Nuclear Regulatory Authority (GNRA), independent from Ghana Atomic Energy Commission as it is currently. The current Regulatory functions of RPB will then be transferred to the new Regulatory Authority (GNRA).

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Present trend of quality assurance/quality control of diagnostic radiology in Ghana
For the present trend, the Regulatory Authority is still largely in charge of QA/QC of diagnostic radiology in Ghana, which ideally is supposed to be an external audit. This practice has been so due to the non-availability of qualified personnel (medical physicists, radiation protection experts, health physicists, etc.) to man diagnostic facilities, and also this requirement not being a major one for granting of authorisation as is in radiotherapy practice in which qualified personnel availability is mandatory. The QA/QC is done through Regulatory inspections that are undertaken by the Radiation Protection Institute to conduct safety assessment for the issuance of authorisations. The safety assessment includes detailed inventory of X-ray equipment, availability of skilled and trained operators, adequacy of personal monitoring, health status and structural shielding adequacy with respect to actual practice, usage of personal protective devices for staff and comforters, usage of radiation protection devices for patients, etc. All these parameters which are related to radiation protection are verified and checked. The inspections are conducted every one to three years depending upon the risk classification of practice and also, whenever there is a major maintenance or change of some key components of the X-ray system. Some quality control measurements that are supposed to be done (because not all parameters listed under each measurement is currently carried out) to monitor the following key components of the X-ray system are: a. Film-processing. b. Basic performance characteristics of the X-ray unit. c. Cassettes and grids. d. Darkroom. e. For specialised equipment. f. View boxes. Some parameters of the above-named components and of more specialised equipment that are supposed to be monitored are as follows: a. For film processing: An index of speed.

Ghana's participation in IAEA project
Ghana is involved in several IAEA Technical Cooperation Projects, but one of significant importance to the subject matter under discussion is on Strengthening Radiological Protection of the Patient and Medical Exposure Control. The main objectives of this Project are to upgrade / strengthen radiological protection of the patient in medical exposures due to: i. Diagnostic Radiology and Interventional Radiological procedures, ii. Nuclear Medicine procedures and iii. Radiotherapy practice. Ghana is participating in four tasks of the Project which are: 1. Surveys of image quality and patient doses in simple radiographic examinations; establishing guidance levels and comparison with international standards. 2. Survey of mammography practice from the optimisation of radiation protection view point. 3. Patient dose management in computed tomography with special emphasis to paediatric patients. 4. Taking steps to avoiding accidental exposure in radiotherapy. For task (1) above, the entrance surface air kerma (ESAK) in some selected X-ray rooms were estimated from output data of the X-ray machine. A calibrated Ionisation chamber was used to measure air kerma (in mGy) at 1 m focus-detector-distance for different kVp settings. The values of X-ray tube output (in mGy/mAs) were plotted against tube potential (kVp) and the resulting output-kVp curve fitted to a square function. Then at the indicted kVp, the analytical equation (1) was used to evaluate the ESAK.
where Y(kVp, FFD) is tube output for actual kVp used during examination (derived from mGy/mAs-kVp curve) at 1 m, mAs is actual tube current-time product used during examination, FSD is the difference between the focus-to-film distance (FFD) and patient thickness (in m) in the anatomic region of interest, BSF is the backscatter factor. The mean entrance surface air kerma estimates from six X-ray rooms from Ghana and other African countries that participated in the IAEA project is shown in   For Task (3) above, the CT dose descriptors that were used were weighted and volume computed tomography dose index (CTDI w , CTDI vol ) and dose length product (DLP). Computed Tomography Dose Index (CTDI) is the patient CT dose defined as the integrated dose profile (in z-direction) for a single slice, normalised to the nominal slice thickness and the DLP for a complete examination. The DLP takes into account the scan length and number of sequences. Standard methods were used to determine the CT dose descriptors [European Commission 1999, McNitt-Gray 2002, Wall 2004. The summary of the mean CTDI w values for adults from four participating hospitals in Ghana for each CT procedure is shown in Table 6 together with other countries that participated in the project (Muhogora et al., 2009 (Muhogora et al., 2009) The summary of the mean DLP values for adults from four participating hospitals in Ghana for each CT procedure is shown in Table 7 together with other countries that participated in the project (Muhogora et al., 2009

Future of quality assurance/quality control
Optimisation of patient dose and image quality is of primary concern in the field of diagnostic imaging. It is recognised that comprehensive quality assurance programmes are a vital component of the optimisation process. Due to the importance of quality control in diagnostic imaging, it is recommended that the appropriate facility personnel review the control tests, data and images periodically (eg. quarterly reviews).
With the availability of training institutions like the School of Allied Health Sciences and the Post-Graduate School of Nuclear and Allied Sciences, more radiologic staff are expected to be churned out to meet the manpower needs of the diagnostic imaging community. For instance, the next 10-15 years, it is projected that about 100 Medical Physicists / Engineers are expected to be trained. There are also plans for the registration of Ghana Society for Medical Physics (GSMP) association. GSMP will draw out necessary modalities to streamline the Education and Training of Medical Physicists and other professionals since Medical Physics experts are identified as one of the professional groups for whom training is mandatory. GSMP will also work on the accreditation and recognition of Medical Physics Profession in Ghana and job placement of Medical Physicists in Hospitals in Ghana, starting with the Teaching Hospitals. It is expected that the human resources trained locally will be employed to establish Physics Units or Departments in the hospitals for the establishment of quality assurance programmes and quality control services that meets regulatory requirements and international best practices. The Medical Physicists will take charge of the routine QC procedures at their departments, undertake periodic dose audits and assist in the establishment of local reference levels and national guidance levels. These levels are to be compared with diagnostic reference levels and other international recommendations which are internationally recognised as a practical tool in the optimisation of radiological protection. The independent GNRA when it becomes operational will put in place regulatory control system including authorisation, inspection and enforcement for the beneficial and peaceful uses of nuclear energy for all practices in Ghana. The GRNA is expected to revise/update the protocols that are currently being used to conduct safety assessment to authorise diagnostic radiology departments in order to keep pace with the emergence of modern medical equipment, and also due to the transition from screen-film technology to digital technology in the country. Additional equipment and test protocols will be needed in this regard. When the country attains the necessary critical mass of expertises, the RA may have to consider licensing some Technical Support Organizations (TSO) including Radiation Protection Institute, which will undertake some of the regulatory inspections of facilities on behalf of the Authority, and submit reports to the RA to issue the necessary authorisation.
A comprehensive review of all the RPB Guides that have been issued since 1995 to 2003 is necessary. This will address current challenges of diagnostic radiology practice due to rapid advances in technology. For instance current regulatory guidelines do not cover the application of non-ionising radiaion such as ultrasound and magnetic resonance imaging (MRI). Quality control for view boxes conditions must be incorporated in the QA programme as this is also part of the radiographic chain. Parameters such as consistency of light output with time, consistency of light output from one box to another and view box surface conditions can be incorporated in the QC measurements. When all appropriate QA programmes are put in place, these will enable the facility to recognise when parameters are out of limits, which could result in poor quality images and can increase the radiation exposure to patients (Compliance Guidance of Radiographic Quality Control, 2003).

Conclusion
It has been increasingly recognised that quality assurance programmes directed at equipment and operator performance can be of great value in improving the diagnostic information content, reducing radiation exposure, reducing medical costs, and improving departmental management. Quality assurance programmes thus contribute to the provision of high quality health care.
There are strong indications that access to diagnostic radiological services will increase in Ghana in the near future. This comes with complex challenges of QA, QC, radiation protection and patient dose management. In all this, the ultimate goal should aim at achieving a diagnostic image that meets clinical requirements with doses to patients as low as possible. Now is the time for all stakeholders (Regulatory Authority, Heath Authorities, Universities and other Training Institutions, Physicists, Hospital or Biomedical Engineers, Radiologists, General Physicians, etc.) to work together to improve the quality of patient protection and management.