Research of Establishing of Standard Radiation Qualities and Radiation Conditions for Use in the Determination and Characteristics of Medical Diagnostic X-ray Equipment / 中国医疗器械杂志

The standard of YY/T 0481-2004 Medical diagnostic X-ray equipment-Radiation conditions for use in the determination and characteristics has been revised and replaced in 2012. This paper first introduces the key technical problems to be solved in establishing standard radiation quality and radiation conditions by comparing the main changes of the two versions standards, including the expression of radiation quality and radiation conditions, the measurement of X-ray tube voltage, and the measuring of the practical peak voltage. Then it introduces a procedure for establishing standard radiation quality and radiation conditions.

Simulation and measurement of diagnostic X-ray radiation qualities / 中华放射医学与防护杂志

Objective To validate the feasibility of the simulationmethod and the reliability of thesimulationresult through comparison between simulation and measurement of the energy spectrum from medical diagnostic X-ray (RQR-Radiation qualities in radiation beans emerging from the X-ray source assembly).Methods A simplified model of the medical diagnostic X-ray RQR radiation quality was established using code of BEAMnrc.The energy spectrum of the same RQR radiation quality were measured through a plane high-purity germanium spectrometer,and compared with the simulationresult.Results The difference of spectral distribution between measurement and simulation was less than 3％,in spite of the convolution processing not happened to the pulse height distribution measured by the spectrometer.And the spectral distribution,fluence,energy fluence,means energy distribution of the radiation was obtained using the code of BEAMDP.Conclusions As indicated above,it is possible to use the simulation of the energy distribution as a foundation for the establishment of X-ray RQR radiation quality.

Evaluation performance of calibration apparatus for dosimeters used in X-ray mammography / 中华放射医学与防护杂志

Objective To fulfill the requirements for uncertainty of the calibration apparatus for dosimeters used in X-ray mammography through setting standard radiation quality at the SSDL and developing calibration procedures.Methods According to IEC 61267-2005 and IAEA TRS No 457 to recommend RQR-M and RQA-M series standard radiation quality,the calibration apparatus was evaluated for long term stability of the radiation field over 8 years from 2006 to 2014,including 10 response quantities,such as field homogeneity,change rate of mean air kerma and scatter radiation contributions and so on.In addition,the reference dose instrument was traced back to the PSDL of PTB in Germany by post during 2008 and 2012.Results The field homogeneity (φ 40 mm) relative error was ± 1.4％.The long term stability of the calibration apparatus was less than ± 2％ (limits of variation).The scatter radiation contributions at their points of test were below 0.12％.The calibration factors traced to PTB were 0.999-1.000.As a result of the calibration apparatus,the expanded uncertainty was ± 3％ (k =2,95％ confidence interval).Conclusions The calibration apparatus may meet the requirements of IEC 61267-2005 and IAEA TRS No 457 and has obtained the license of metrology from national regulatory authority.The laboratory now performs very well to calibrate dosimeters used in X-ray mammography.

Crescimento vegetativo e produção de óleo essencial de plantas de alecrim cultivadas sob telas coloridas / Vegetative growth and yield of essential oil of the rosemary plants development when cultivated under colored screens

O alecrim é planta exótica e o interesse no seu cultivo tem crescido ao longo dos anos, pois pode ser utilizado tanto para fins medicinais como aromáticos e largamente utilizado na medicina popular; no entanto, o conhecimento fitotécnico sobre a espécie é bastante limitado. O objetivo deste trabalho foi avaliar o crescimento vegetativo, o teor e o rendimento de óleo essencial de plantas de alecrim, cultivadas sob telas com diferentes características espectrais. As plantas foram cultivadas em vasos distribuídos inteiramente ao acaso, com seis repetições, sob estruturas cobertas individualmente nas cores vermelha e azul, com sombreamento de 50% e a pleno sol (0%). Quatro meses depois, foram avaliadas as características de crescimento: altura do ramo principal, diâmetro do caule, número de folhas, área foliar, matéria seca das folhas, caule e raízes, os índices fisiológicos: razão de área foliar (RAF), área foliar específica (AFE) e a razão de peso foliar (RPF) e o teor e rendimento do óleo essencial. Plantas de alecrim cultivadas em pleno sol e sob malha azul produziram maior biomassa seca de folhas e maiores teores e rendimentos do óleo essencial. O ambiente a pleno sol influenciou o crescimento, a produção de biomassa e as variáveis AF, AFE, RAF e RPF de plantas de alecrim em relação às plantas cultivadas sob telas coloridas. As plantas submetidas às condições de sombreamento apresentaram maior massa seca foliar e caulinar. Porém, conclui-se que altas intensidades alteraram significativamente a distribuição de massa seca particionada e que o uso de diferentes telas não influenciou nas características fisiológicas das plantas de alecrim, independente da cor.

Rosemary is an exotic plant and the interest in its cultivation has been growing along the years, because it can be used for medicinal or aromatic ends used in popular medicine, however the agricultural knowledge about the species is quite limited. The objective of this study was to evaluate the growth and the content and yield of the essential oil of rosemary plant when grown under fabric screens with different spectral characteristics. Plants were grown in pots distributed in a completely randomized design with six replicates, under structures individually covered in red and blue fabric, with 50% shade and full sunlight (0%).Four months later, we assessed both growth characteristics: main branch height, stem diameter, leaf number, leaf area, dry matter of leaves, stems and roots and physiological indices: leaf area ratio (LAR), specific leaf area (SLA) and leaf weight ratio (LWR) content and yield of the essential oil. Rosemary plants grown under full sun and blu net produced higher dry leaf biomass and higher essential oil content and yield The full sun environment influenced the growth, biomass production and the variables LA, SLA, LAR and LWR in rosemary plants in comparison to plants grown under colored fabric screens. Plants under shading conditions showed higher leaf and stem dry mass. However, it is concluded that high intensity significantly alter the distribution of partitioned dr237y mass and that the use of different fabric screens did not affect the physiological characteristics of rosemary plants, regardless its color.

Comparison of the energy response for several dosimeters used in mammography / 中华放射医学与防护杂志

Objective To evaluate whether eight kinds of dosimeters satisfy the clinical mammography dose measurement through the comparison of energy response.Methods According to GB/T 19629-2005,the energy responses of eight available mammography dosimeters were determined for ten standard radiation qualities in the range 25-40 kVp at the SSDL using a refrence-class dosimeter.Results Except 2000S,the energy response factors of all the other dosimeters were consistent within ±5%.Conclusions The energy response of ionizing chamber type is better than other types of dosimeters.

A Study on the Effects of Wedge Filter in Peripheral Dose Distribution / 대한치료방사선과학회지

The peripheral dose distributions of wedge fields of Co-0 gamma-ay and 10MV x-ay were measured by the solid state detector controlled by means of semiautomatic water phentom system. The measurements were made on the principal plane parallel to the cross section of wedge filter (blade and ridge direction). For parallel motion of the detector to the beam axis the distance from the margin of radiation field at surface were 3, 5 and 10cm. For tranverse motion the depth of measurement were dm, 5, 10 and 15cm. The followings were drawn from the measurement. 1. The peripheral dose of the blade side of wedges was generally higher than that of the ridge side at symmetric point about beam axis. 2. In the superficial region phenomena of dose build-p appeared. 3. For Co-0 gamma-ay field, the peripheral dose did not monotonously decrease with the distance from the field margin but increase in some range, consequently showing a peak dose. 4. The peripheral dose did not only depend on radiation quality and field size, but also on wedge angle and wedge direction.