基于平板探测器的DR系统原理及使用维护

针对采用平板探测器技术做为数字化方案实现的直接数字化X线摄影系统，本文重点探讨了平板探测器特点，介绍了系统的工作原理和成像技术，以及系统日常在设备运行过程中的维护技术。     

液相分析仪紫外检测器标准物质的研制及不确定度评定

研制了液相分析仪紫外检测器检定用标准物质,简要介绍了标准物质的配制方法,重点介绍了标准物质的均匀性检验和稳定性检验,详细分析了标准物质不确定度的评定,对各级医疗机构药品检验具有重要的指导意义。     

免疫亲和柱净化光化学衍生高效液相色谱-荧光检测法测定动物类药材中黄曲霉毒素

目的建立动物类药材中黄曲霉毒素B1,B2,G1,G2的免疫亲和柱净化光化学衍生高效液相色谱-荧光检测(HPLC-FLD)法。方法样品经甲醇-水(80∶20)提取后,通过免疫亲和柱净化、柱后光化学衍生、高效液相色谱-荧光检测器测定。结果在优化条件下,黄曲霉毒素G2,G1,B2,B1的检出限分别为0.15,0.25,0.1,0.2μg/kg,回收率为78.8%～106.7%,RSD均低于7.1%。结论所用方法简便快速、灵敏度高、重现性好,可满足动物类药材中黄曲霉毒素检测的需要。     

HPLC-ELSD法同时测定知母药材中5种成分的含量

目的采用高效液相色谱-蒸发光散射检测方法(HPLC-ELSD)建立同时测定知母药材中新芒果苷、芒果苷、知母皂苷BⅡ、宝藿苷Ⅰ及知母皂苷AⅢ的含量测定方法。方法采用Agilent poroshell 120 EC-C₁₈柱,流动相采用乙腈-0.2%醋酸水系统,梯度洗脱;柱温为30℃,流速为0.7 ml/min;蒸发光散射检测器以氮气为雾化气,雾化气温度为40℃,漂移管温度为90℃,氮气体积流量为2.0 L/min;进样量为20μl。结果 5种成分均能达到基线分离,新芒果苷24.1～386μg/ml(r=0.999 3)、芒果苷23.2～371μg/ml(r=0.998 6)、知母皂苷BⅡ54.2～867.2μg/ml(r=0.995 6)、宝藿苷Ⅰ5.3～84.8μg/ml(r=0.996 8)、知母皂苷AⅢ10～160μg/ml(r=0.998 9)的浓度范围内呈现良好的线性关系。5种成分的平均加样回收率在101.8%～105.0%之间,重复性RSD小于2.4%,知母药材中上述5种成分含量分别为1.62%、0.82%、7.36%、0.07%、0.34%。结论该方法...     

Functionalized 1,4‐Benzothiazine: A Versatile Scaffold with Diverse Biological Properties

1,4‐Benzothiazines are known to represent a class of medicinally important heterocyclic compounds which are extensively used in drug design. They have wide biological properties which qualify them as excellent scaffolds in therapeutic and medicinal research. Thus, many derivatives of this compound have been synthesized as target structures in novel drug development. Hence, the motivation for this present review was the known widespread application of the 1,4‐benzothiazine scaffolds.     

Wireless amplified NMR detector for improved visibility of image contrast in heterogeneous lesions

To demonstrate the capability of a wireless amplified NMR detector (WAND) to improve the visibility of lesion heterogeneity without the use of exogenous contrast agents, a cylindrically symmetric WAND was constructed to sensitively detect and simultaneously amplify MR signals emitted from adjacent tissues. Based on a two‐leg high‐pass birdcage coil design, this WAND could be activated by a pumping field aligned along the main field (B₀), without perturbing MR signal reception. Compared with an equivalent pair of external detectors, the WAND could achieve more than 10‐fold gain for immediately adjacent regions. Even for regions with 3.4 radius distance separation from the detector's cylindrical center, the WAND was at least 1.4 times more sensitive than an equivalent pair of surface arrays or at least twice as sensitive as a single‐sided external surface detector. When the WAND was inserted into a rat's rectum to observe adjacent tumors implanted beneath the mucosa, it could enhance the detection sensitivity of lesion regions, and thus enlarge the observable signal difference between heterogeneous tissues and clearly identify lesion boundaries as continuous lines in the intensity gradient profile. Hyperintense regions observable by the WAND existed due to higher levels of blood supply, which was indicated by a similar pattern of signal enhancement after contrast agent administration. By better observing the endogenous signal contrast, the endoluminal WAND could characterize lesions without the use of exogenous contrast agents, and thus reduce contrast‐induced toxicity.     

Supplementary values of the dosimetric parameters kNR and Em for various types of detectors in 6 and 15 MV photon fields

The present communication broadens the data base for determinations of the non-reference condition correction factor k_NR needed in high-energy photon dosimetry to accomplish the use of various detectors under non-reference conditions. Following our previous strategy of calculating semiempirical values of k_NR and correlating them with the mean photon energy E_m at the point of measurement in a large water phantom, the values of E_m are now stated for 6 and 15 MV photon radiations of accelerators with and without flattening filters, square field sizes from 1 to 30 cm side length and depths from 0 to 28 cm. The unambiguity of the k_NR-E_m correlation is again confirmed and is quantified by fitting formulae for air-filled ionization chambers, TLD detectors and Si diodes. This survey provides a practicable access to the k_NR values, particularly for the non-water equivalent detectors to be used in small-field dosimetry     

The effect of uranium migration on radionuclide distributions for soil samples at the El-Gor area,Sinai, Egypt

The concentrations and distributions of the activity of natural radionuclides in soil samples were investigated in fifteen soil samples at El-Gor area representing two profiles (A and B) using a HP–Ge detector and alpha counting by SSNTD (CR-39), respectively. The average concentrations of the radionuclides ²³⁸U, ²²⁶Ra, ²³⁵U, ²³²Th and ⁴⁰K are 203.4, 177.23, 9.77, 43.33 and 386.22 Bq kg⁻¹ (dry weight), respectively, and profile A and ²³⁸U, ²²⁶Ra, ²³⁵U, ²³²Th and ⁴⁰K have average concentrations of 232.58, 246, 11.7, 31.7, and 277.07 Bq kg⁻¹ for profile B, respectively. The eTh and eU were estimated to detect the migration process of uranium into or out of an area or uranium to or from the studied profiles. The results indicate a migration of uranium by 29% for profile A and 65.37% for profile B. The activity ratio (²³⁸U/²²⁶Ra) was found to be 0.9 in profile A and 1.15 in profile B. These ratios coincide with the uranium migration processes. The responsible mass corresponding to the measured ²²⁶Ra activity was also calculated. The radon activity concentrations for the two profiles are nearly 300 Bq m⁻³. The emanation coefficient (η) was calculated from the ratio of the expected radon activity to the measured radon for the studied soil samples. The value of η was found to depend only on the radium activity regardless to soil formation.     

Double waffle-cone technique using twin Solitaire detachable stents for treatment of an ultra-wide necked aneurysm

Several stent-supported coiling techniques have been devised for treating wide-necked bifurcation aneurysms including the Y-stent and waffle-cone constructs. The Y-stent technique is not technically possible with obtusely oriented daughter vessels, and the waffle-cone method is inadequate for aneurysms with necks exceeding the stent’s maximal expansion diameter. We describe here the novel use of the Solitaire electrolytically detachable slotted stent (Solitaire, ev3, Irvine, CA, USA) featuring large-sized cells to fashion a concentric “double waffle-cone” construct. This method enabled the doubling of the neck coverage to treat an ultra-wide necked middle cerebral aneurysm with obtusely oriented daughter branches. The technique relies on the intra-cell crossing of the first stent using the second stent delivery microcatheter and fine tuning the relative position with the aid of cross-sectional cone-beam computed tomographic angiography to achieve optimal coverage of the neck prior to detachment of the stents in position. A retrievable stent with large cells such as the Solitaire device is optimal for this application given the need for relative adjustment of the deployment before final stent release to avoid under- or over-penetration of the distal stent struts into the aneurysm dome. An additional advantage of this approach over the kissing-stent technique is the absence of intraluminal stent struts, which was confirmed here by down-the-barrel cross-sectional imaging. The double waffle-cone construct enabled the successful coiling of the aneurysm with no post-procedural ischemic events detected on diffusion-weighted MRI and with stable complete embolization and no residual filling or in-stent stenosis at 6 month follow-up.     

Natural and anthropogenic radioactivity levels and the associated radiation hazard in the soil of Oodalia Tea Estate in the hilly region of Fatickchari in Chittagong,Bangladesh

Radioactivity in the soil of a tea garden in the Fatickchari area in Chittagong, Bangladesh, was measured using a high-resolution HPGe detector. The soil samples were collected from depths of up to 20 cm beneath the soil surface. The activity concentrations of naturally occurring ²³⁸U and ²³²Th were observed to be in the range of 27 ± 7 to 53 ± 8 Bq kg⁻¹ and 36 ± 11 to 72 ± 11 Bq kg⁻¹, respectively. The activity concentration of ⁴⁰K ranged from 201 ± 78 to 672 ± 81 Bq kg⁻¹, and the highest activity of fallout ¹³⁷Cs observed was 10 ± 1 Bq kg⁻¹. The average activity concentration observed for ²³⁸U was 39 ± 8 Bq kg⁻¹, for ²³²Th was 57 ± 11 Bq kg⁻¹, for ⁴⁰K was 384 ± 79 Bq kg⁻¹ and for ¹³⁷Cs was 5 ± 0.5 Bq kg⁻¹. The radiological hazard parameters (representative level index, radium equivalent activity, outdoor and indoor dose rates, outdoor and indoor annual effective dose equivalents, and radiation hazard index) were calculated from the radioactivity in the soil.