Visual demonstration of aliasing in planar nuclear medicine imaging: The importance of correct collimator selection by nuclear medicine practitioners

Aliasing artefact is an imaging distortion phenomenon experienced in a wide variety of medical imaging modalities. This case report illustrates its occurrence during planar gamma camera nuclear medicine imaging under non-clinical conditions using experimental incorrect selection of collimators. In accordance with provision of an optimal service, nuclear medicine practitioners are recommended to have sufficient technical expertise along with knowledge of gamma camera operation. The purpose, construction and interaction of collimators used during planar imaging are presented herein with specific regards to the aliasing phenomenon. Furthermore, this case report recommends the careful planning of worklists to avoid frequent collimator changes to reduce the risk of human error.     

Radioiodination and bioevaluation of rolipram as a tracer for brain imaging: In silico study,molecular modeling and gamma scintigraphy

Brain imaging is considered one of the most fruitful applications of radioisotope scanning. Rolipram, a selective phospodiesterase‐4 inhibitor, has been labeled using [¹²⁵I] with chloramine‐T (Ch‐T) as an oxidizing agent. Factors, such as the amount of substrate, pH, the amount of oxidizing agent, temperature, and the reaction time, have been systematically studied to optimize the iodination process. In addition, bio‐distribution studies have indicated that the brain uptake of [¹²⁵I]iodorolipram is 7.6 ± 0.33 injected dose/g organ at 10 minutes post‐injection, which cleared from the brain with time until it reaches 1.30 ± 0.17% at 1 hour post‐injection. Therefore, iodorolipram could be considered as a potential, new selective radiotracer for brain imaging.     

学习风格特征对腹腔镜扶镜技能训练的影响

目的 分析医学生的学习风格特征,探讨不同的学习风格特征对腹腔镜扶镜助手技能训练的影响。方法 在腹腔镜扶镜助手扶镜技能训练前采用Kolb学习风格量表于2020年9月至12月对哈尔滨医科大学附属第四医院60名实习医生和40名专硕研究生学习风格特征进行评估;然后分析比较实习医生和专硕研究生学习风格特征的差异,以及不同学习风格特征对腹腔镜扶镜技能训练效果的影响。结果 实习医生和专硕研究生学习风格特征差异有统计学意义(P<0.001)。实习生群体中以发散型学习风格为主,研究生群体中以聚合型学习风格为主。学习风格特征对腹腔镜扶镜技能效果有显著影响。实习医生和专硕研究生聚合型学习风格受试者在扶镜技能训练中,视野居中、水平位、最佳视野每个周期平均失误数均明显少于发散、同化和调节型学习风格的受试者。结论 医学生中不同学习群体有着不同的学习风格特征。在腹腔镜扶镜技能训练中学习风格特征对训练效果有显著影响。医学教育中应该充分兼顾不同学习风格特征的特点,充分发挥学生学习风格优势。     

On the Applicability of Camera Lens Protectors in Emergency Luminescence Dosimetry

In this work, the optically stimulated luminescence (OSL) properties of camera lens protectors and their potential use in emergency dosimetry were investigated. Camera lens protectors can be attached to mobile phones, which are commonly carried by individuals and may be useful in estimating an emergency dose. The presented results confirm the great potential of this type of glass material for dose determination. The glass protectors exhibit advantageous properties, such as linear dose dependence in the range of at least 0.6–10 Gy, minimum detectable dose at the level of tens of mGy, and good measurement repeatability for samples of the same type. Significant fading during the first day after exposure is an undesirable feature of tested glass. Nevertheless, the application of the correction for fading shows promising results in the dose recovery process.     

Hydrogen sulfide is a novel prosecretory neuromodulator in the Guinea-pig and human colon

BACKGROUND & AIMS: Hydrogen sulfide (H(2)S) has been suggested as a novel gasomediator. We explored its unknown neuromodulatory role in human and guinea-pig colon. METHODS: We used immunohistochemistry to detect H(2)S-producing enzymes cystathionine gamma-lyase (CSE) and cystathionine beta-synthase (CBS) in enteric neurons, Ussing chambers to measure mucosal ion secretion, and neuroimaging with voltage- and Ca(++)-sensitive dyes to record H(2)S effects on guinea-pig and human enteric neurons. RESULTS: More than 90% of guinea-pig and human submucous and myenteric neurons were colabeled for CSE and CBS. Myenteric interstitial cells of Cajal were CSE-immunoreactive. The exogenous H(2)S donor NaHS (0.2-2.5 mmol/L) concentration-dependently increased chloride secretion in human and guinea-pig submucosa/mucosa preparations, but not in the colonic epithelial cell line T84. The secretory response was reduced significantly by tetrodotoxin (0.5 micromol/L), capsaicin desensitization (10 micromol/L), and the transient receptor potentials vanilloid receptor 1 antagonist capsazepine (10 micromol/L). The endogenous H(2)S donor L-cysteine also induced secretion that was diminished significantly by capsaicin desensitization, the CBS inhibitor amino-oxyacetic acid, and the CSE inhibitor propargylglycine. NaHS increased spike discharge in 23% of guinea-pig and 36% of human submucous neurons, but had no effect on Ca(++) mobilization in cultured guinea-pig enteric neurons. This excitatory response was reduced significantly by capsaicin desensitization and capsazepine, but not by glibenclamide (10 micromol/L). CONCLUSIONS: The presence of H(2)S-producing enzymes in human and guinea-pig enteric neurons, the excitatory action on enteric neurons, and the prosecretory effects of NaHS suggest H(2)S as a novel gut-signaling molecule. Its action mainly involves transient receptor potentials vanilloid receptor 1 receptors on extrinsic afferent terminals, which in turn activate enteric neurons.     

激光衍射法测量肌节长度动态特性

本文首次在国内用激光衍射法测量了肌节长度的动态变化。测量装置主要由光电耦合元件与单板机构成。采样频率在每秒100到200次之间可调,测量范围为1.5～3.0μm,绝对精度为0.02μm。用600条/mm的理想光学衍射光栅随机标定20次,相对误差为2.4±1.2％,20条爪蟾缝匠肌等张收缩的测量表明本装置可以满足一般测量的要求,其中两组典型结果在文中进行了讨论。该方法价廉实用,可为心血管、药理、电生理等研究提供细胞水平的动态参数。     

Magnesium ascorbyl phosphate vesicular carriers for topical delivery; preparation,in-vitro and ex-vivo evaluation,factorial optimization and clinical assessment in melasma patients

Ascorbic acid (vitamin C) is an antioxidant that is widely used in cosmetics in skincare products. Due to the excessive low stability of ascorbic acid in cosmetic formulations, the stabilized ascorbic acid derivative, magnesium ascorbyl phosphate (MAP) was formulated as vesicular carriers; ethosomes and niosomes. The aim was to deliver MAP at the intended site of action, the skin, for sufficient time with enhanced permeation to get an effective response. Ethosomes were formulated using a full 3² factorial design to study ethanol and phospholipid concentration effect on ethosomes properties. Niosomes were formulated using 2³ factorial designs to study the effect of surfactant type, surfactant concentration and cholesterol concentration on niosomes properties. The prepared formulations were evaluated for their Entrapment efficiency, particle size, polydispersity index, zeta potential and % drug permeated. The optimized ethosomal and niosomal formulations were incorporated into carbopol gel and evaluated for their permeation, skin retention and stability. A comparative split-face clinical study was done between the ethosomal and niosomal formulations for melasma treatment using Antera 3 D^® camera. The optimized ethosomal and niosomal gels showed comparable controlled permeation and higher skin retention over their ethosomes and niosomes formulations respectively. Magnesium ascorbyl phosphate ethosomal gel showed clinically and statistically significant melanin level decrease after one month while MAP niosomal gel showed clinically and statistically significant melanin level decrease after six months. A combination of MAP ethosomes and niosomes could be promising skincare formulations for melasma and hyperpigmentation short and long-term treatment.     

积分时间和频率同时可调的线阵CCD驱动

电荷耦合器件（CCD）的应用越来越广泛，在生物医学图像的获取方面也不例外。而CCD驱动电路的设计是CCD应用的关键问题之一。介绍了一种利用可编程逻辑器件（CPLD）实现积分时间和频率同时可调的线阵CCD驱动方法。实验结果表明，具有电路简单、集成度高以及调试方便等优点。     

数码相机在设备维修工作中的应用

主要总结了在医疗设备维修领域中使用数码相机的一些技巧及心得。