Radiation Protection

このレポートでは、過去5年間に東京電力福島第
一原発事故の影響を受けた地域で実施された多数
の調査の結果に基づき、2011年3月に起きた同
事故の結果として現在生じている生態学的状況を
明らかにする。これは福島県の森林、河川、氾濫
原、河口域の放射能汚染に関して現時点で判明し
ていることを記録にとどめようとする試みであ
る。福島県と全国の環境に放出された放射性核種
の半減期の長さを考えれば、それが生態系に与え
る影響を理解することは不可欠である。
また、このレポートでは、日本の今後数年、数十
年間について予測されることに関する洞察を提供
するために、キシュテムとチェルノブイリの放射
能事故で深刻な汚染を受けた森林・水生生態系の
研究を参考にした。

Radon isotopes (222, 220, 219) are radioactive gases produced by the disintegration of radium isotopes 226, 224 and 223, which are decay products of uranium238, thorium232 and uranium235 respectively. All are found in the earth's crust. Solid elements, also radioactive, are produced by radon disintegration. Radon is classed as a rare gas in the periodic table of elements, along with helium, argon, neon, krypton and xenon. When disintegrating, radon emits alpha particles and generates solid decay products, which are also radioactive (polonium, bismuth, lead etc.). The potential danger of radon lies in its solid decay products rather than the gas itself. Whether or not they are attached aerosols, radon decay products can be inhaled and deposited in the bronchopulmonary tree to varying depths according to their size. Radon today is considered to be the main source of human exposure to natural radiation. At the international level, radon accounts for 52% of global average exposure t...

In a working group of the Belgian Hospital Physicists Association (BHPA), a new protocol has been developed for comprehensive testing of computed tomography scanners. The tests were selected to verify if the scanner is technically adequate, if preprogrammed patient protocols are up-to-date, and if exposure values displayed at the console are sufficiently correct. In addition, they will ensure that the participating medical physics expert (MPE) gets a full understanding of the system to enable him/her to guide optimization processes and allow automated patient dosimetry. Several new test procedures had to be developed. The tests go beyond the criteria identified in the EC guidance document radiation protection (RP) 91 and its successor RP 162. The results of the tests of the BHPA protocol are discussed in the light of the acceptability criteria in RP 91 and RP 162. It is concluded that the ensemble of tests in the BHPA protocol and in RP 162 provide very useful information on the sca...

The marked increase in radiation exposure from medical imaging, especially in children, has caused considerable alarm and spurred efforts to preserve the benefits but reduce the risks of imaging. Applying the principles of the Image Gently campaign, data-driven process and quality improvement techniques such as process mapping and flowcharting, cause-and-effect diagrams, Pareto analysis, statistical process control (control charts), failure mode and effects analysis, "lean" or Six Sigma methodology, and closed feedback loops led to a multiyear program that has reduced overall computed tomographic (CT) examination volume by more than fourfold and concurrently decreased radiation exposure per CT study without compromising diagnostic utility. This systematic approach involving education, streamlining access to magnetic resonance imaging and ultrasonography, auditing with comparison with benchmarks, applying modern CT technology, and revising CT protocols has led to a more tha...

Der Aufsatz vergleicht die Strahlenschutzregime im Uranbergbau der DDR und der Bundesrepublik Deutschland nach dem Zweiten Weltkrieg bis in die achtziger Jahre. In beiden Systemen stellte sich das Problem, den Schutz der Beschäftigten mit einer möglichst effizienten Förderung von Uranerz im Kontext des Kalten Krieges zu vereinbaren. Unterschiede existierten im gesellschaftlichen und politischen Kontext des Bergbaus, weniger in der verwendeten Technik und in den zugrunde gelegten Strahlenschutznormen. Hinsichtlich letzterer orientierten sich die Ende der fünfziger Jahre einsetzenden Strahlenschutzmaßnahmen an Empfehlungen der Internationalen Strahlenschutzkommission (ICRP). Allerdings zeichnete sich der sächsisch-thüringische Uranbergbau nicht nur durch sein größeres Ausmaß (und entsprechend größeres Gefährdungspotential) aus, sondern auch durch quasi-militärische Geheimhaltung.

Prolonged exposure to radon, the largest source (69%) of natural radioactivity, may cause lung cancer and bronchial tissue damage. So monitoring of radon at places of high radioactivity and in underground mines is important to assess the radiological hazards to occupational workers. For these reasons radon measurements were carried out in some coal mines of Baluchistan, Pakistan. The measurements were based upon passive detection of radon using CN-85 track detectors in Box Type Dosimeters. The radon concentration varied from 121 to 408 Bq m−3 in the mines under study. The computed radon dose varied from 1.38 to 4.67 mSv yr−1 with an average of 2.19±0.5 mSv yr−1. These coal mines have been found to be safe from radon-related health hazards.

Aim
Data was collected to establish local Diagnostic Reference Levels (DRLs) for the CT component of our most common SPECT/CT studies.

Methods
432 SPECT/CT scans were analysed from Dec 2014 - Dec 2015. CT dose values of CTDIVol (mGy) and DLP (mGycm) were recorded as well as patient’s weight and the anatomical area, for different scan procedures.
Octreotide, MIBG and Lutetium scans, were grouped together as neuro-endocrine tumour (NET) studies.
DRLs for CTDIVol and DLP were calculated as the 75th percentile, from patients weighing 50-90kg following IPEM Report 88.

Results
CTDIVol and DLP DRLs are given below for:
• Hepato-Biliary scans: 2.2mGy and 93mGycm
• I131 post-ablative scans: 2.4mGy and 98mGycm
• Parathyroid scans: 2.6mGy and 107mGycm (with 2 SPECT/CT scans giving a total study DLP of 215mGycm)
• NET studies: 2.2mGy and 171mGycm (ranging from 2.0mGy and 84mGYcm for an Abdo, Pelvis to 2.43mGy and 279mGycm for Head, Chest, Abdo, Pelvis)
• All Bone scans: 11.8mGy and 461mGycm (ranging from 2.2mGy and 91mGycm for low-dose localisation CT of the torso to 16.0mGy and 574mGycm for diagnostic non-contrast CT of the lumbar spine)

Conclusion
Local DRLs were created and can be compared with initial data released by the IPEM working party on Hybrid CT DRLs.

Digital radiography systems based on flat-panel detectors have been introduced into clinical practice in the past few years. The high detective quantum efficiency of these detectors allows the radiation dose to be reduced while maintaining image quality, an issue particularly significant for pediatric radiography. Another important aspect for dose optimization and monitoring is the integration of the detector into a computer-controlled x-ray examination system. This enables full control and complete reporting of all dose-relevant exposure parameters, including the determination of the exposure indicator and the patient dose (kerma-area product). In this paper the implementation of these principles in the Philips Digital Diagnost DR system is described and their relevance for pediatric applications is discussed.