Nuclear medicine exposure in the United States, 2005-2007: preliminary results

Medical radiation exposure of the U.S. population has not been systematically evaluated for almost 25 years. In 1982, the per-capita dose was estimated to be 0.54 mSv and the collective dose 124,000 person-Sv. The preliminary estimates of the National Council on Radiation Protection and Measurements Scientific Committee 6-2 medical subgroup are that, in 2006, the per-capita dose from all medical exposure (not including radiotherapy) had increased almost 600% to 3.0 mSv and the collective dose had increased more than 700% to approximately 900,000 person-Sv. >Nuclear medicine accounted for only about 2% of all procedures but 26% of the total collective dose from diagnostic studies in medicine. In 1982, the estimated number of nuclear medicine procedures was about 7.5 million. The per-capita effective dose from nuclear medicine was 0.14 mSv and the collective dose was 32,000 person Sv. By 2005, the estimated number of procedures had increased to about 19.6 million. The per-caput effective dose increased to about 0.75 mSv and the collective dose to about 220,000 person Sv. There also has been a marked shift in the type of procedures being performed with cardiac scanning accounting for about 70% of procedures.     

UK nuclear medicine survey 2003-2004

OBJECTIVES: This survey was designed to assess the trends in the frequencies of nuclear medicine procedures in the UK and to determine their contributions to the annual collective effective dose to the UK population. The average activities administered by nuclear medicine departments were compared with guidance on diagnostic reference levels issued by the Administration of Radioactive Substances Advisory Committee. METHOD: The survey was carried out by e-mailing a questionnaire to every known nuclear medicine centre in the UK. RESULTS: The total number of procedures performed annually has increased by 36% over the last 10 years to a level of about 11 procedures per 1000 head of population in the financial year 2003-2004. Seventy-three per cent of all nuclear medicine administrations are for planar imaging, with single-photon emission computed tomography and positron emission tomography contributing 16% and 2%, respectively. Non-imaging diagnostic procedures represent 7% of all nuclear medicine administrations, and therapy 2%. Bone scans continue to be the most frequent procedure. The UK annual collective effective dose from diagnostic nuclear medicine is about 1600 man Sv, resulting in an annual per caput dose of nearly 0.03 mSv. Bone scans are the largest contributor to the collective dose, but myocardium scans are close behind. Planar imaging is responsible for 62% of the total collective effective dose from diagnostic nuclear medicine in the UK, with single-photon emission computed tomography, positron emission tomography and non-imaging contributing 33%, 5% and 0.3%, respectively. CONCLUSIONS: The practice of nuclear medicine is still expanding in the UK with single-photon emission computed tomography imaging of the myocardium rapidly approaching bone scans as the main contributor to population exposure. The activities administered for most procedures have remained substantially unchanged and adhere closely to those recommended by the Administration of Radioactive Substances Advisory Committee.     

2016年广东省临床核医学基本状况调查

目的 调查广东省各地区临床核医学诊疗基本情况,评估临床核医学应用过程中的职业人员与公众的辐射照射风险,探讨防控辐射风险对策。方法 成立广东省临床核医学基本信息调查组,采用问卷普查及现场抽查形式,对全省核医学科工作人员、设备、核医学诊疗核素和人次、工作人员个人剂量水平以及医院放射防护管理措施等进行了调查。结果 2016年广东省开展核医学放射诊疗单位共71家,从业人员733人,核医学科工作人员人均年有效剂量为（0.55±0.66） mSv/年。全省核医学设备189台,其中SPECT/CT 59台（含SPECT 5台）,PET/CT 28台,甲状腺功能仪54台。使用核素总量1.15×10⁸ MBq,其中⁹⁹Tc^m为7.39×10⁷ MBq,¹⁸F为2.38×10⁷ MBq,¹³¹I为1.70×10⁷ MBq。全年核素诊疗325 903人次,平均频度为2.97人次/千人口。结论 近20年,广东省临床核医学得到飞速发展,21个市中18个市设立了核医学科;核素使用量比1998年增长了414%,核素诊疗年频度比1998年增长了111%。临床核医学的发展增加了职业人群、公众的潜在辐射照射及环境污染的风险,规范核医学科放射性药品的使用及排污管理是将来医用辐射管理的关注重点。     

Radiation doses from nuclear medicine patients to an imaging technologist: relation to ICRP recommendations for pregnant workers.

The ICRP has now recommended that the dose limit to the surface of the mother's abdomen during the declared term of pregnancy is reduced to 2 mSv. Direct measurements of the radiation dose to technologists carrying out a variety of imaging studies were made. The average dose ranged from 0.3 micro Sv for a liver scan to 5.3 micro Sv for a brain scan. Using national data for the frequency of nuclear medicine studies, a weighted average figure of 1.5 micro Sv per study was derived. A technologist could therefore perform approximately eight imaging studies per day during the declared term of her pregnancy and remain within the proposed limit. Generally, there should be no need to alter a technologist's duties during her pregnancy, and these findings should be helpful in allaying any anxiety.     

Effective dose equivalent from radiopharmaceuticals

The concept of effective dose equivalent, which was introduced by the International Commission on Radiological Protection (ICRP) for occupationally exposed workers, has also created the possibility of expressing by means of a single figure, the radiation risk to patients undergoing different medical radiodiagnostic procedures. In this study, we present the effective dose equivalent for various nuclear-medicine investigations. The figures given are primarily based on a review of data contained in the literature on the mean absorbed dose to various organs. In many cases, however, our own calculations, using biokinetic data derived from the literature, have been used.It was found that for the different radiopharmaceuticals, the effective dose equivalent per activity unit administered extends over an interval of five orders of magnitude, from 0.00015 to 20 mSv/MBq. For the technetium-labelled compounds, the absorbed dose for 90% of the substances lies within the narrower interval between 0.0060 and 0.025 mSv/MBq. With the aid of the figures presented, each nuclear medicine department will be able to estimate the effective dose equivalent and, hence, the risk to patients undergoing different investigation.     

Nuclear medicine training and practice in the Czech Republic

Nuclear medicine in the Czech Republic is a full specialty with an exclusive practice. Since the training program was organized and structured in recent years, residents have had access to the specialty of nuclear medicine, starting with a two-year general internship (in internal medicine or radiology). At present, nuclear medicine services are provided in 45 departments. In total, 119 nuclear medicine specialists are currently registered. In order to obtain the title of Nuclear Medicine Specialist, five years of training are necessary; the first two years consist of a general internship in internal medicine or radiology. The remaining three years consist of training in the nuclear medicine specialty itself, but includes three months of practice in radiology. Twenty-one physicians are currently in nuclear medicine training and a mean of three specialists pass the final exam per year. The syllabus is very similar to that of the European Union of Medical Specialists (UEMS), namely concerning the minimum recommended numbers for diagnostic and therapeutic procedures. In principle, the Czech law requires continuous medical education for all practicing doctors. The Czech Medical Chamber has provided a continuing medical education (CME) system. Other national CMEs are not accepted in Czech Republic.     

Radiation dose rates from patients undergoing positron emission tomography: implications for technologists and waiting areas

Increasingly hospitals are showing an interest in developing their imaging services to include positron emission tomography (PET). There is therefore a need to be aware of the radiation doses to critical groups. To assess the effective whole-body dose received by technologists within our dedicated PET centre, each staff member was issued with a dose rate meter, and was instructed to record the time spent in contact with any radioactive source, the dose received per working day and the daily injected activity. On average each technologist administered 831 MBq per day. The mean whole-body dose per MBq injected was 0.02 μSv/MBq^–1. The average time of close contact (<2.0 m) with a radioactive source per day was 32 min. The average effective dose per minute close contact was 0.5 μSv/min^–1, which resulted in a mean daily effective dose of 14.4 μSv. No technologist received greater than 60 μSv (the current UK limit for non-classified workers) in any one day, and in general doses received were less than 24 μSv, the daily dose corresponding to the proposed new annual limit for non-classified workers of 6.0 mSv per annum. However, we recognise that the layout of nuclear medicine departments will not mirror our own. We therefore measured the instantaneous dose rates at 0.1, 0.5, 1.0 and 2.0 m from the mid-thorax on 115 patients immediately after injection, to provide estimates of the likely effective doses that might be received by technologists operating dual-headed coincidence detectionsystems, and others coming into contact in the waiting room with patients who have been injected with fluorine-18 fluorodeoxyglucose. The mean (95th percentile) dose rates measured at the four aforementioned distances were 391.7 (549.5), 127.0 (199.8), 45.3 (70.0) and 17.1 (30.0) μSv/h^–1, respectively. A number of situations have been modelled showing that, with correct planning, FDG studies should not significantly increase the effective doses to technologists. However, one possible area of concern is that, depending on the number of patients in a waiting area at any one time, accompanying persons may approach the limits set by the new UK IRR 1999 regulations for members of the public. Received 30 September and in revised form 27 December 1999     

Pattern of radiopharmaceutical administration to patients between 1982 and 1986

Analysis of the workload of a nuclear medicine department over the period 1982 to 1986 has shown the prevalence of repeated investigations in individual patients. Records from 23,152 investigations on 17,063 patients indicated that 88.5% received a single administration and only 0.5% received more than four doses of the same radiopharmaceutical. Patterns of usage of a wide range of radiopharmaceuticals are presented and show that the technetium bone imaging agent is the radiopharmaceutical most commonly used for repeated administrations. Analysis of the radiation dose to individual patients arising from radiopharmaceutical administration has shown that only two patients in the survey exceeded 50 mSv per annum and approximately 25% of patients exceeded 5 mSv per annum.     

Dose to patients through nuclear medicine procedures in a department in northern Greece

Diagnostic nuclear medicine procedures in a large hospital in northern Greece during 1984-1988 have been surveyed in order to estimate the radiation burden to the patients. The mean effective dose equivalent (EDE) was found to be 1.96 mSv/examination and 2.46 mSv/patient, allowing for the fact that a number of patients underwent more than one examination. Apart from EDE, absorbed dose has been calculated for bone marrow, thyroid, gonads, kidneys and bladder. Patients undergoing multiple examinations have been used to calculate true 'patient dose distribution' as well as 'patient time-weighted dose distribution'. Because of the predominance of renal examinations, 8.5 fatal renal malignancies are expected per 100,000 patients.     

江苏省2011-2018年放射工作人员职业性外照射个人剂量监测结果分析

目的 了解江苏省2011-2018年放射工作人员个人剂量监测基本情况,分析其变化趋势,为保护放射工作人员健康管理提供理论基础和科学依据.方法 通过国家个人剂量登记系统,采集我省放射工作人员职业外照射个人剂量监测结果等相关数据,对其进行回顾分析.结果 2011-2018年监测江苏省放射工作人员共176 134人,总年集体...     

Estimation of close contact doses to young infants from surface dose rates on radioactive adults

A general method is given to estimate the dose to an infant held in close contact to a radioactive parent. Calculated values of effective exposure times are given for various radiopharmaceuticals corresponding to a simplified sequence of periods of close contact. When multiplied by a measurement of the dose rate on the surface of an adult, these times can be used to give a quick upper estimate of a close contact dose. This allows a decision whether it is necessary to issue instructions for restricting the duration of close contact to an adult patient, before the patient leaves a nuclear medicine department. Estimates of close contact dose have been made from measurements of surface dose rate using these effective exposure times. Doses to infants from adults who have undergone diagnostic radiopharmaceutical procedures can be kept below 1 mSv without imposing restrictions in close contact. A close contact dose of 1 mSv will be exceeded by activities of 131-I iodide greater than 112 MBq.     

Comparison of three cold kit reconstitution techniques for the reduction of hand radiation dose.

In the performance of conventional nuclear pharmacy work, personnel usually receive the highest hand radiation dose during reconstitution of 99Tcm-labelled radiopharmaceuticals. This study was conducted to compare the hand radiation doses incurred during the preparation of 99Tcm-labelled radiopharmaceuticals using three different reconstitution procedures: (1) the standard reconstitution method (i.e. withdrawing 99Tcm activity and normal saline [NS] into the same syringe before adding to the cold kit) (standard); (2) an alternative reconstitution procedure using two syringes to add normal saline separately before 99Tcm activity to the cold kit (NS/Tc); and (3) a standard reconstitution procedure using a robotic system (Amercare Syringe Fill Station, model NuMed SFS 3a, Amercare Ltd, Oxon, UK) (robot). Radiation doses were monitored by thermoluminescent dosimeters (Landauer Inc., Glenwood, IL, USA) on the base of the fourth finger (i.e. ring finger) of the non-dominant hand and on the mid-portion of the second finger (i.e. index finger) of the dominant hand. Three sets of ring badges were measured for each procedure, with 10 stimulated or real reconstitutions per set. Two different radiopharmaceutical kits were evaluated: 99Tcm-MDP, as it is the most frequently used radiopharmaceutical in the majority of nuclear medicine departments (all three reconstitution methods; i.e. standard, NS/Tc and robot), and 99Tcm-sestamibi, as it is not only reconstituted with the highest amount of radioactivity but is also the most frequently dispensed radiopharmaceutical in our laboratory (standard and robot). All kits were prepared from an elution vial containing a standardized amount of 99Tcm activity (i.e. 104.4 +/- 3.6 GBq). To each of the cold MDP and sestamibi kits, 20.7 +/- 1.2 GBq and 44.2 +/- 0.7 GBq of 99Tcm activity were added, respectively. Average accumulated radiation doses for 10 reconstitutions to the fingers (non-dominant/dominant) for the preparations of 99Tcm-MDP were as follows: 14.2 +/- 0.9 mSv/2.8 +/- 0.8 mSv (standard), 10.0 +/- 0.6 mSv/2.7 +/- 0.2 mSv (NS/Tc), and 0.6 +/- 0.1 mSv/1.3 +/- 0.1 mSv (robot). For 99Tcm-sestamibi, the average accumulated radiation doses for 10 reconstitutions to the fingers (non-dominant/dominant) were 6.7 +/- 0.7 mSv/4.6 +/- 0.5 mSv (standard) and 1.1 +/- 0.1 mSv/3.1 +/- 0.4 mSv (robot). When compared to the standard reconstitution method, our results show that the NS/Tc method slightly reduced radiation dose to the non-dominant hand, without any significant reduction for the dominant hand. However, the robot has proved to be the most effective method to considerably reduce radiation dose to both hands. A robotic system should be a useful ALARA (as low as reasonably achievable) tool to prepare other high-activity 99Tcm-labelled radiopharmaceuticals, as well as therapeutic and PET radiopharmaceuticals.     

Effective dose equivalents to patients undergoing cerebral angiography.

PURPOSE: To determine values of the effective dose equivalent, HE, for patients undergoing diagnostic cerebral angiography and compare these values with radiation doses received by patients undergoing other diagnostic examinations of the head. METHODS: The radiographic techniques for ten patients undergoing cerebral angiography were recorded and used to obtain the product of the entrance skin dose and the x-ray beam cross-sectional area. These measured dose-area product data were converted into effective dose equivalents employing published conversion factors which take into account the part of the patient anatomy irradiated and the radiographic technique factors employed. RESULTS: The average patient HE value was 10.6 mSv, with a range of 2.7-23.4 mSv. Fluoroscopy contributed approximately 67% of the total HE, with cut films and digital subtraction angiography contributing 26% and 7%, respectively. CONCLUSIONS: The radiation doses (HE) to patients undergoing diagnostic cerebral angiography are comparable to the patient doses in nuclear medicine brain studies where the typical HE is approximately 10 mSv. In CT, the patient dose is approximately 2 mSv, whereas in plain skull x-ray examinations, the patient dose is much lower at approximately 0.15 mSv.     

Communicating radiation exposure: a simple approach

OBJECTIVE: The aim of this article is to provide a general method to help explain radiation exposure to patients presenting for nuclear medicine procedures. The concept is to convert the effective dose from any nuclear medicine procedure to the equivalent time in months or years to obtain the same effective dose from background radiation. METHODS: The effective dose of each common diagnostic nuclear medicine procedure was obtained from the literature and the corresponding background equivalent radiation time (BERT) was calculated assuming an average background radiation of 3 mSv/y. RESULTS: A table of the BERT has been compiled for common nuclear medicine procedures. CONCLUSION: The BERT table provides a simple approach to help physicians and technologists effectively communicate radiation exposure information and perhaps potential radiation risk.     

Diagnostic reference value. Critical evaluation of the term with the example of nuclear medicine studies in Austria

The aim of this study was to collect administered activities of important nuclear medicine diagnostic examinations and to identify frequencies as well as age distributions in the light of hybrid devices in Austria. Based on the survey data a re-evaluation of dose reference levels for nuclear medicine has been published in June 2010 in the novella of the Austrian Medical Radiation Protection Regulation (MedStrSchV) (8), also an estimate of the average individual doses of the total population. Accurate data on nuclear medicine studies of 34% of all Austrian nuclear medicine units could be collected. RESULTS: Extrapolated there are about 150000 nuclear medicine examinations per year performed in Austria. The median age of patients is thereby 62 years. The results of this study resulted in 65% of the dose reference values to change, whereas 48% had to be revised downwards and 17% upwards. Additionally, 5 new reference values were included in the list; three more were taken out, however. The estimation of the individual effective patient dose for each offered examination was on average 4.7 mSv. An extrapolation based on the total exposure of the population with regard to uninvolved persons and children led to 0.07 mSv per year by nuclear medicine examinations. CONCLUSION: The published diagnostic reference values correspond to the normal investigative practice in Austria and are compliant with most international recommendations. The term "optimal value" has been removed from the text of the law, because such wording would be misleading.     

Doses and population irradiation factors for Canadian radiation technologists (1978 to 1988)

Individual and collective radiation doses received by Canadian radiation technologists (RTs) working in diagnostic radiology, nuclear medicine and radiotherapy are summarized for the period 1978 to 1988. The data were obtained directly from the National Dose Registry, Department of National Health and Welfare. Over the 11-year study period the mean annual dose equivalent fluctuated around 0.2, 1.8 and 1.1 mSv for RTs working in diagnostic radiology, nuclear medicine and radiotherapy respectively. Over the same period the occupational collective dose equivalent decreased in diagnostic radiology (by 44%) and radiotherapy (by 35%) and increased in nuclear medicine (by 45%). Approximately 10,000 RTs are monitored each year, with an estimated total occupational collective dose equivalent of about 3.6 person-sieverts. Analysis of dose distribution data showed that only 1.3% of all monitored RTs received an annual whole-body dose equivalent greater than the current legal limit for members of the public (5 mSv). Approximately half of the RTs working in nuclear medicine and radiotherapy received an annual dose equivalent in excess of 0.5 mSv; only 7.3% of their diagnostic radiology counterparts exceeded this level. Demographic data showed a high preponderance of young women in all three RT classifications, and an analysis of the radiation risks to this occupational group revealed increases of up to 12% above the risk associated with a "standard" adult working population exposed to the same collective dose equivalent.     

A survey of PET activity in Germany during 1999

Positron emission tomography (PET) is the most powerful molecular imaging technique currently available for clinical use. The aim of this study was to provide public health information on PET procedures carried out in Germany - a country with a very high number of PET installations. To this end, all facilities that in 1999 were running at least one dedicated PET system were contacted and requested to provide information in a questionnaire on the radiopharmaceuticals applied, the total number and age distribution of patients and volunteers examined, the main diagnostic applications and the range of administered activities. Based on the information provided by 48 of the 60 PET facilities in Germany, an annual frequency of about 0.34 PET procedures per 1,000 inhabitants was estimated, associated with an annual per capita effective dose of about 1.9 micro Sv. Averaged over all PET procedures, the mean effective dose to patients was 5.6 mSv. The age distribution of patients and volunteers was skewed markedly towards higher ages; only a very small fraction (<3%) of patients were children younger than 15 years while older patients, and especially those in the age group between 41 and 65 years, were overrepresented relative to the general population. In total, 28 different PET radiopharmaceuticals were used, with only half of these having been administered to more than 20 patients each. The most frequently applied radiotracer was the glucose analogue 2-[(18)F]fluoro-2-deoxy- D-glucose (FDG), which was utilised in more than 84% of all PET procedures. For this tracer, the median value for activities applied for examinations in the three-dimensional (3D) acquisition mode was only half of that used for two-dimensional (2D) measurements. Based on a statistical analysis of the distribution of mean FDG activities administered to patients in the 48 PET facilities who responded to our inquiry, diagnostic reference levels of 370 and 200 MBq are proposed for the 2D and the 3D mode, respectively.     

广东省放射诊疗工作人员个人剂量监测调查水平的探讨

目的 探讨广东省放射诊疗工作人员个人剂量监测调查水平.方法 采用方便抽样方法,以2016-2019年委托广东省职业病防治院个人剂量监测室进行个人剂量监测的广东省放射诊疗工作人员为调查对象,对其个人剂量进行监测与分析.结果 2016-2019年分别监测诊断放射学、牙科放射学、核医学、放射治疗、介入放射学和其他应用工作人员...     

Radiation exposure of medical staff from interventional x-ray procedures: a multicentre study

The purpose of this study was to analyse the radiation exposure of medical staff from interventional x-ray procedures. Partial-body dose measurements were performed with thermoluminescent dosimeters (TLD) in 39 physicians and nine assistants conducting 73 interventional procedures of nine different types in 14 hospitals in Germany. Fluoroscopy time and the dose–area product (DAP) were recorded too. The median (maximum) equivalent body dose per procedure was 16 (2,500) μSv for an unshielded person; the partial-body dose per procedure was 2.8 (240) μSv to the eye lens, 4.1 (730) μSv to the thyroid, 44 (1,800) μSv to one of the feet and 75 (13,000) μSv to one of the hands. A weak correlation between fluoroscopy time or DAP and the mean TLD dose was observed. Generally, the doses were within an acceptable range from a radiation hygiene point of view. However, relatively high exposures were measured to the hand in some cases and could cause a partial-body dose above the annual dose limit of 500 mSv. Thus, the use of finger dosimeters is strongly recommended.     

Effective doses to members of the public from the diagnostic application of ionizing radiation in Germany

The exposure of the German population to man-made radiation results mainly from diagnostic X-ray and nuclear medical examinations. Data are presented about the annual frequency and the average dose of the various examination types for West Germany in the years 1990–1992. According to these data a yearly average of approximately 1550 diagnostic examinations using ionizing radiation were performed per 1000 inhabitants resulting in an annual per caput effective dose of 1.9 mSv. Despite the frequent use of alternative examination techniques, such as sonography, nuclear magnetic resonance and endoscopy, the frequency of X-ray and nuclear medical examinations is still increasing. If collective risk assessments are done using the per caput effective dose, at least the age distribution of the patients must be considered. This leads to a “risk-modifying factor“ of 0.6–0.7 for patients to be applied to the ICRP risk coefficient of 5 % per Sv valid for the general population. However, radiation risk must always be viewed in context with disease- and therapy-related risks and balanced against the benefit of the diagnostic examination, which should always exceed the risk for a well-indicated procedure. Received 12 June 1996; Revision received 21 October 1996; Accepted 8 November 1996