Current status of medical radiation exposure in Korea – recent efforts to develop a radiation exposure control system focussed on justification and optimisation

Abstract

Radiation exposure from diagnostic medical imaging has increased in Korea. Radiological societies play a key role in radiation safety issues in Korea, including guidelines, accreditation, advocacy, scientific activity, and education. Any medical radiation exposure must be justified, and examinations using ionising radiation must be optimised. Education of referring physicians and radiologists is also important for justification. Medical physicists and radiographers have an important role to play in quality management and optimisation. Regulations are essential to control medical radiation exposure. Therefore, national organisations have made a significant effort to regulate and monitor medical radiation exposure using guidelines, accreditation, and even the law. Medical radiation exposure must be controlled, and this could be achieved by continuous interest from health professionals and organisations.

Keywords

Medical exposure Radiological protection Healthcare

1. INTRODUCTION

1.1. Healthcare system in Korea

Korea has a public healthcare insurance system with mandatory registration of all healthcare providers and residents providing universal coverage. The public health system mainly relies on privately owned hospitals and is very extensive, covering a large range of medical situations. Nearly all aspects of the healthcare system are regulated by the Korean Government (Chun et al., 2009). Step-by-step expansion of coverage, coupled with demand for a higher quantity and quality of healthcare, have increased investment and resources, and placed heavy financial pressures on the system. Hospitals develop services that are not covered by national health insurance (NHI) in order to increase revenue. Medical services not covered by NHI are also regulated by the Korean Government (Fig. 1).

Fig. 1.

Overview of healthcare system in Korea. IHA, individual health assessment.

1.2. Current status of radiation exposure in Korea

Korea has two separate control systems for medical radiation exposure. Firstly, diagnostic radiation control falls under the Medical Services Act, under the responsibility of the Ministry of Health and Welfare (MOHW). Secondly, therapeutic radiation and nuclear medicine control falls under the Nuclear Safety Act, under the responsibility of the Nuclear Safety and Security Commission (Table 1).

Table 1.

Medical radiation exposure control system in Korea.

	Diagnostic radiation equipment	Therapeutic radiation equipment
Act	Medical Services Act	Nuclear Safety Act
Responsible ministry	Ministry of Health and Welfare	Nuclear Safety and Security Commission

There are two components to the rules under the Medical Services Act: (1) safety control of diagnostic x-ray-generating equipment, and management of equipment and radiological protection facilities, regulated by the Korean Centre for Disease Control; and (2) installation and operation of quality assurance systems for computed tomography (CT), magnetic resonance imaging (MRI), and mammography. These cover the management of equipment, occupational exposure, and radiological protection facilities, but the current regulation is not focussed on patient safety.

Given the size of the population of South Korea, the country has many items of medical imaging equipment, which is indicative of the high number of imaging procedures being undertaken. The number of imaging procedures performed in Korea is comparable, or even higher, compared with the numbers of imaging procedures performed in Organization for Economic Cooperation and Development (OECD) countries. Korea has a very high rate of medical imaging equipment adoption. In 2011, Korea ranked fifth and sixth in the world in terms of the number of MRI and CT units per million population, respectively. However, the number of MRI and CT examinations per 1000 population in Korea seems to be relatively low (OECD, 2013). This is because examinations that are privately funded are not included, yet these represent the majority of examinations in Korea. As these privately funded examinations are highly commercial, quality control is very important in order to prevent abuse.

The annual number of diagnostic radiological examinations in Korea increased rapidly from 2006 to 2011; the total number of diagnostic radiological examinations and CT scans increased by an average of 8% and 14% y⁻¹, respectively. The annual per-caput effective dose in the Korean population increased by 10% from 2007 to 2011. In 2011, the estimated annual per-caput effective dose was 1.4 mSv. The data in this study are probably underestimated because the main data source was NHI data, and did not include out-of-pocket procedures, such as voluntary health screening programmes (Kim, 2013).

Professional organisations are actively collaborating with many national agencies regarding quality and safety. In Korea, national agencies interested in medical radiation exposure include the MOHW; the Ministry of Science, ICT, and Future Planning; and the Ministry of Food and Drug Safety. The National Evidence-based Healthcare Collaborating Agency (NECA) and the Health Insurance Review and Assessment Service (HIRA) exist under MOHW. NECA and HIRA are creating guidelines together with the Korean Society of Radiology (KSR).

2. RADIATION EXPOSURE CONTROL SYSTEM FOR IMAGING STUDIES

2.1. Efforts for justification

Any medical radiation exposure must be justified, and examinations using ionising radiation must be optimised. The first principle is justification of medical exposures. Justification goes beyond optimisation, where awareness, appropriateness, and audit are used for the implementation of justification. Practically, knowledgeable and effective communication with patients (informed consent) and with healthcare professionals (education and training) is needed for awareness. It is vital to raise awareness about safety among health professionals. Communication with patients includes the provision of information about risks and benefits, and gaining informed consent. Appropriate criteria and referral guidelines can be used by physicians to make decisions regarding justification. Lastly, the importance of clinical audits to improve justification is emphasised. The adoption of clinical audits is encouraged through payment systems, accreditation programmes, etc.

There are three stages of radiation exposure control for imaging studies. The first stage is equipment control. In Korea, there are strict regulations regarding radiological protection of patients, implemented as the Radiation Protection Act of the Ministry of Food and Drug Safety in 1995 and the accreditation programme in 2004. The second stage is imaging quality control. In Korea, an accreditation programme exists for phantom test and clinical imaging evaluation; the Medical Act for CT, MRI, and mammography. This accreditation programme is similar to the Mammography Quality Standards Act of the USA.

As of January 2015, Korea has not organised guidelines comparable to the appropriateness criteria of the USA, or iRefer of the UK. Currently, KSR is actively developing clinical diagnostic imaging guidelines adapted from other guidelines. Over the last 2 or 3 y, several guidelines have been published using government funding, and several more guidelines are currently in development. Since 2011, KSR has published many guidelines for radiological imaging and quality management, and contrast management. In 2016, work commenced on the development of comprehensive clinical imaging guidelines. This is a collaborative project between KSR and NECA.

KSR is fully aware of the importance of justification of these studies, and has made many contributions to the project (Table 2). KSR has played a significant role in improving healthcare in Korea. KSR largely consists of regional societies, a board of directors, and subspecialty societies. Many committees focus on quality and safety (e.g. health policy and practice, health insurance, radiation safety, accreditation, and clinical practice guidelines). KSR has recently created a subcommittee called the ‘Radiology Advocacy Network of Korea for Quality and Safety’ (RANK-QS). This started as a voluntary organisation (Korean Advocacy Group for Radiation Protection and Quality Management) in 2013. Currently, the subcommittee hold monthly meetings and an annual symposium for radiation safety, contrast media, quality management for imaging facilities and radiologists, clinical imaging guidelines, etc.

Table 2.

Major efforts for quality and safety made by the Korean Society of Radiology (KSR).

2004	Establishment of Korean Institute for Accreditation of Medical Imaging (CT, MRI, and mammography)
2005	Certification for diagnostic imaging centre of excellence by KSR
2008∼	Assessment and education for national health screening (mammography boot camp, e-learning programme for mammography interpretation)
2008∼	Set national diagnostic reference level with Korean CDC (mammography, CT, x rays, paediatrics, dental x rays, and fluoroscopic examinations)
2012	2012 KSR Committee for Clinical Guidelines → development of comprehensive clinical imaging guidelines (referral guidelines)
2013	Korean Advocacy Group of Radiation Protection and Quality → 2015 Radiology Advocacy Network of Korea for Quality and Safety

CDC, Centre for Disease Control and Prevention. CT, computed tomography. MRI, magnetic resonance imaging.

2.2. Efforts for optimisation

The as low as reasonably achievable (ALARA) principle is a basic philosophy for the optimisation of radiological protection and safety. First, appropriate equipment, software, technique, and parameters must be used for radiological protection. Dosimetry must be performed and documented to determine typical doses to patients for common procedures for diagnostic radiological procedures. Diagnostic reference levels (DRLs) are used to review whether the optimisation is adequate, or if corrective action is required if the typical doses/activities exceed or fall below the DRL. Quality assurance programmes, including standard operating procedures, equipment quality control and clinical audits, must be established (IAEA, 2014).

After the separation of pharmacy distribution from medical practice in 2000 in order to reduce medical fees, the rate of self-referral increased. Self-referral in diagnostic imaging inevitably leads to overuse. If untrained physicians operate radiological equipment or try to interpret images, the number of poor-quality examinations will increase. On 19 January 2001, the National Assembly of Korea approved various acts, including quality management for specific medical equipment. By this law, quality management of specific medical equipment such as CT, MRI and mammography was launched by MOHW. In collaboration with MOHW, KSR developed guidelines and standards of quality management for mammography, CT and MRI equipment. KSR established the Korean Institute for Accreditation of Medical Imaging (KIAMI) as a relevant professional foundation, and MOHW authorised KIAMI to serve as an organisation for quality inspection. All CT, MRI and mammography equipment must have quality control tests mandated by the Medical Service Act Article 38 [installation and operation of special medical equipment (Do et al., 2007)].

In 2005, 3773 units of medical equipment underwent quality inspection, and 7% failed to meet the required standard. Given that the failure rate was much higher in the pilot study performed before inauguration of quality management, this result shows that the quality of medical imaging performed at certified units is improving, and public health in Korea has benefited from these improvements (Fig. 2).

Fig. 2.

Failure rates for equipment on quality control tests. CT, computed tomography. Mammo, mammography. MRI, magnetic resonance imaging.

The National Institute of Food and Safety Evaluation is executing a national survey on radiation doses in Korea. A Korean database of patient radiation exposure in radiological examinations has been established for CT, fluoroscopy, angiography, mammography and radiography. DRLs were published for chest postero-anterior scanning and mammography in 2008, for CT scanning in 2009, for paediatric chest radiography in 2010, for general radiography in 2012, and for dental imaging in 2013. Korean DRLs of these examinations are summarised in Table 3.

Table 3.

Diagnostic reference levels in Korea.

X ray
Examination type	ESD (mGy)	Examination type	ESD (mGy)	Examination type	ESD (mGy)
Head (AP)	2.7	Neck (AP)	1.98	Clavicle (AP)	1.92
Head (LAT)	3.11	Neck (LAT)	0.97	Shoulder (AP)	1.84
Chest (PA)	0.58	T-spine (AP)	4.09	Forearm (AP)	0.6
Chest (AP)	1.75	T-spine (LAT)	9.22	Elbow (AP)	0.35
Chest (LAT)	3.08	L-spine (AP)	4.74	Wrist (AP)	0.27
Abdomen (AP)	3.9	L-spine (LAT)	12.17	Hip joint (AP)	3.68
Pelvis (AP)	3.94	L-spine (OBL)	6.7	Knee (AP)	0.6
				Ankle (AP)	0.39
Fluoroscopy

Examination type	DAP (mGy cm²)	Examination type	DAP (mGy cm²)
Barium enema	46.4	Intravenous pyelogram	13.1
Upper gastrointestinal series	29.3	Endoscopic retrograde cholangiopancreatography	56.9
Swallowing study	9.1	Hysterosalpingogram	17.4
Small bowel series	33.8

Intervention
Examination type	ESD (mGy)	DAP (mGy cm²)	Time (min)	Number
Transcatheter arterial chemoembolisation	511.75	209.94	16.61	4.51
Arteriovenous fistula	31.77	27.69	18.76	3.62
Percutaneous transhepatic biliary drainage	58.6	18.45	4.21	0
Cerebral angiography	404.85	226.03	9.31	7.3
Guglielmi detachable coil embolisation	2264		51.1	6.57

Computed tomography			Dental x ray
	CTDI_vol (mGy)	DLP (mGy cm)		Entrance dose (mGy)	DAP (mGy cm²)
Head	60	1000	Intra-oral	3.07	87.4
Chest	20	700	Panorama		110.9
Abdomen	15	550	Cephalo		161.1
Mammography
Average glandular dose 1.36 mGy

AP, antero-posterior. CTDI_vol, computed tomography dose index volume. DAP, dose-area product. DLP, dose length product. ESD, entrance skin dose. LAT, lateral. OBL, oblique. PA, postero-anterior.

3. ISSUES AND CHALLENGES

The first issue and challenge concern diagnostic radiation dose measurement. Dosimetry will have to contribute fundamentally to patient protection, and a clear purpose is required. CT dose index volume and dose length product would be required in the case of CT performance monitoring, and effective dose would be needed for risk assessment purposes. Secondly, there is a need to determine whether it is necessary to measure the radiation dose for every diagnostic radiological examination, or only for relatively high-dose examinations. In some state governments in the USA, dose reporting is required for CT and fluoroscopy. Finally, there is a need to determine the level of enforcement.

Regarding the direction for diagnostic radiation control, there is an issue regarding personal dose tracking in Korea. Some groups believe that it must be necessary for reducing radiation dose. Other groups including radiology professionals do not agree with that idea because it is not applicable for justification and optimisation. Procedure tracking could be a substitute for personal dose tracking. However, there are several issues to consider, such as legal problems with the protection of personal information. HIRA had tried to establish a sharing system for imaging information. There is a need for practical implementation of justification for each diagnostic procedure. The first step affecting patient dose is the clinical decision to expose a patient to radiation, and this is the scope of justification. Education of referring physicians and radiologists is also important for justification.

Although medical radiation is clearly beneficial, there are potential risks, and it is necessary to distinguish between real risks and calculated/theoretical risks. Physicians should work with patient advocacy organisations to communicate the potential radiation risks and health benefits of imaging procedures more effectively (Amis et al., 2007). The dose equivalent should be expressed as the equivalent number of chest radiographs, and the risk of cancers should be expressed as the number of additional cases in the exposed population (BEIR VII, 2006). Patients must be protected from unnecessary and unintended radiation exposure. Understanding, communication, and cooperation of relevant stakeholders will be needed for patient protection. Medical physicists and radiographers play an important role in quality management and optimisation.

4. CONCLUSIONS

Radiation exposure from diagnostic medical imaging has increased in Korea. Each stakeholder plays a unique and complementary role for each patient-centred care system regarding radiological safety. Radiological societies play a key role in radiation safety issues in Korea, including guidelines, accreditation, advocacy, scientific activity, and education. Regulations are essential to control medical radiation exposure. Therefore, national organisations have made a significant effort to regulate and monitor medical radiation exposure using guidelines, accreditation, and even the law.

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