Proposed DRLs for Mammography in Switzerland.

OBJECTIVES: The aim of this study is to propose Diagnostic Reference Levels (DRLs) values for mammography in Switzerland. Methods: For the data collection, a survey was conducted among a sufficient number of centres, including 5 University hospitals, several cantonal hospitals, and large private clinics, covering all linguistic regions of Switzerland to be representative of the clinical practice. The data gathered contained the mean glandular dose (MGD), the compressed breast thickness (CBT), the mammography model and the examination parameters for each acquisition. The data collected was sorted into the following categories: 2D or digital breast tomosynthesis (DBT) examination, craniocaudal (CC) or mediolateral oblique (MLO) projection, and 8 categories of compressed breast thickness (CBT) ranging from 20mm to 100mm in 10mm intervals. Results: 24762 acquisitions acquired in 31 centres on 36 mammography units from 6 different manufacturers were collected. The analysis showed that the data reflects the practice in Switzerland.The results revealed that the MGD is larger for DBT than for 2D acquisitions for the same CBT. From 20-30mm to 90-100mm of CBT, the 75th percentile of the MGD values obtained increased from 0.81mGy to 2.55mGy for 2D CC acquisitions, from 0.83mGy to 2.96mGy for 2D MLO acquisitions, from 1.22mGy to 3.66mGy for DBT CC acquisitions and from 1.33mGy to 4.04mGy for DBT MLO acquisitions. Conclusion: The results of the survey allow us to propose Swiss DRLs for mammography according to the examination type (2D/DBT), projection (CC/MLO) and CBT. The proposed values are very satisfactory in comparison with other studies. .

ANNUAL EXPOSURE OF THE SWISS POPULATION FROM MEDICAL IMAGING IN 2018.

Nationwide surveys on radiation dose to the population from medical imaging are recommended in order to follow trends in population exposure. The goal of the 2018 survey was to investigate the current exposure. The invoice coding information was collected in five university hospitals and large clinics. To improve the estimation of the effective dose delivered in computed tomography (CT), we collected dose data from different Dose Archiving Communication Systems. On average, we found that 1.2 radiological examinations per year and per inhabitant were performed. Dental radiography was the most frequent examination (48% of all the X-ray examinations), followed by conventional radiography (36%) and CT (11%). The average annual effective dose was estimated to be 1.48 mSv per inhabitant, with CT representing 64% of that dose. Our results show that the exposure of the Swiss population from medical imaging has remained stable since 2013, despite a 15% increase in the number of CT examinations.

Derivation of new diagnostic reference levels for neuro-paediatric computed tomography examinations in Switzerland.

PURPOSE: Definition of new national diagnostic reference levels (DRLs) for volume computed tomography dose index (CTDIvol) and dose length product (DLP) for neuro-paediatric CT examinations depending on the medical indication. METHODS: Paediatric cranial CT data sets acquired between January 2013 and December 2016 were retrospectively collected between July 2016 and March 2017 from eight of the largest university and cantonal hospitals that perform most of the neuro-paediatric CTs in Switzerland. A consensus review of CTDIvol and DLP was undertaken for three defined anatomical regions: brain, facial bone, and petrous bone, each with and without contrast medium application. All indications for cranial CT imaging in paediatrics were assigned to one of these three regions. Descriptive statistical analysis of the distribution of the median values for CTDIvol and DLP yielded values in the minimum, maximum, 25th percentile (1st quartile), median (2nd quartile), and 75th percentile (3rd quartile). New DRLs for neuro-paediatric CT examinations in Switzerland were based on the 75th percentiles of the distributions of the median values of all eight centres. Where appropriate, values were rounded such that the DRLs increase or at least remain constant as the age of the patient increases. RESULTS: Our results revealed DRLs for CTDIvol and DLP up to 20% lower than the DRLs used so far in Switzerland and elsewhere in Europe. CONCLUSIONS: This study provides Swiss neuro-paediatric CT DRL values to establish optimum conditions for paediatric cranial CT examinations. Periodic national updates of DRLs, following international comparisons, are essential.

EXPOSURE OF THE SWISS POPULATION BY RADIODIAGNOSTICS: 2013 REVIEW.

In 2013, a nationwide investigation was conducted in Switzerland to establish the population's exposure from medical X rays. A hybrid approach was used combining the Raddose database accessible on-line by the participating practices and the Swiss medical tariffication system for hospitals. This study revealed that the average annual number of examinations is 1.2 per inhabitant, and the associated annual effective dose is 1.4 mSv. It also showed that computed tomography is the most irradiating modality and that it delivers 70 % of the total dose. The annual effective dose per inhabitant registered a 17 % increase in 5 y and is comparable with what was recently reported in neighbouring countries.

Exposure of the Swiss population by medical x-rays: 2008 review.

Nationwide surveys on radiation dose to the population from medical radiology are recommended in order to follow the trends in population exposure and ensure radiation protection.The last survey in Switzerland was conducted in 1998,and the annual effective dose from medical radiology was estimated to be 1 mSv y j(-1) per capita. The purpose of this work was to follow the trends in diagnostic radiology between 1998 and 2008 in Switzerland and determine the contribution of different modalities and types of examinations to the collective effective dose from medical x-rays. For this reason, an online database(www.raddose.ch) was developed. All healthcare providers who hold a license to run an x-ray unit in the country were invited to participate in the survey. More than 225 examinations, covering eight radiological modalities, were included in the survey. The average effective dose for each examination was reassessed. Data from about 3,500 users were collected (42% response rate). The survey showed that the annual effective dose was 1.2 mSv/capita in 2008. The most frequent examinations are conventional and dental radiographies (88%). The contribution of computed tomography was only 6% in terms of examination frequency but 68% in terms of effective dose. The comparison with other countries showed that the effective dose per capita in Switzerland was in the same range as in other countries with similar healthcare systems, although the annual number of examinations performed in Switzerland was higher.

An education and training programme for radiological institutes: impact on the reduction of the CT radiation dose.

OBJECTIVES: To establish an education and training programme for the reduction of CT radiation doses and to assess this programme's efficacy. METHODS: Ten radiological institutes were counselled. The optimisation programme included a small group workshop and a lecture on radiation dose reduction strategies. The radiation dose used for five CT protocols (paranasal sinuses, brain, chest, pulmonary angiography and abdomen) was assessed using the dose-length product (DLP) before and after the optimisation programme. The mean DLP values were compared with national diagnostic reference levels (DRLs). RESULTS: The average reduction of the DLP after optimisation was 37% for the sinuses (180 vs. 113 mGycm, P < 0.001), 9% for the brain (982 vs. 896 mGycm, P < 0.05), 24% for the chest (425 vs. 322 mGycm, P < 0.05) and 42% for the pulmonary arteries (352 vs. 203 mGycm, P < 0.001). No significant change in DLP was found for abdominal CT. The post-optimisation DLP values of the sinuses, brain, chest, pulmonary arteries and abdomen were 68%, 10%, 20%, 55% and 15% below the DRL, respectively. CONCLUSIONS: The education and training programme for radiological institutes is effective in achieving a substantial reduction in CT radiation dose.

[State of measures of quality assurance for radiotherapy units in Switzerland]. / Zum Stand der Qualitätssicherungsmassnahmen an Röntgentherapieanlagen in der Schweiz.

In Switzerland 57 X-ray therapy units are in operation at present. According to the Swiss Ordinance on Radiation Protection, a quality-assurance program must regularly be applied in to these units. However, as the Swiss X-ray Ordinance gives explicit control parameters only for diagnostic units, the present article issues proposals for the realization of a quality-assurance program for the therapy units. In this regard, it is distinguished between checks performed by technical personnel of the X-ray manufacturers and checks performed by a medical physicist with corresponding qualification, or under his supervision. The so-called mentor project for the performance of annual constancy checks in institutes without medical physicists is also taken into account. These proposals should be helpful for the discussion and clarification of competencies, hence contributing to standardization of control practices in Switzerland.