F30-ⅡD型X线机限时器电路故障维修

故障现象:摄影准备工作就绪后,按下手闸,X线管球产生X线对胶片进行曝光.但经冲洗加工后,照片密度明显偏低.在对X线管球进行外观检验、真空度试验、灯丝加热试验、负荷试验等各种性能测定后,再次进行曝光试验,照片密度仍然存在偏低现象.     

F30-ⅡB型X线机检修

故障现象 在拍摄腰椎正位片时，突然闻及球管头方向啪!啪!放电声，几乎同时墙上闸刀的三相保险丝也熔断。此时，我们意识到高压部分有严重地漏电或短路的可能，故停用。     

F30-ⅡG型X线机限时器故障一则

故障现象开机各指示表指示正常,床上球管照像时,按下两档手闸曝光,瞬间曝光结束,重复曝光时曝光不止。     

F99-Ⅰ型X线机限时电路的调整

一台F99-Ⅰ型X线机已工作十余年，经放射科技术投照人员介绍，近年来在给定的摄影条件内曝光，X线逐渐出现不足的现象。经在不同条件下测试，KV和mA均无差异，由此确认限时电路可能出现误差。为此参照图纸及有关资料对限时电路进行了仔细调整。调整后各条件下的曝光量都取得了满意的效果。     

F30-ⅡD型X线机电子管限时器故障的检修

故障现象 摄影时，按下手闸，机器曝光不止，只好强行关机。     

F78—11型X线机限时电路故障

故障现象 X线机曝光不截止，调整时间选择各档不起作用。     

F30-ⅢB型X线机控制电路二点改进

本文对Ｆ３０－ⅢＢ型Ｘ线机控制电路作了如下二点改进。（１）灯丝加热稳压源控制电路的改进：该部分电路与许多国产Ｘ线机灯丝加热稳压源电路差别较大，采用全自动电子交流稳压器电路结构较复杂，有些元器件易损坏，其中小型继电器ＪＤ４、ＪＤ５，不能正常工作就很常见...     

F30-30 mA移动式X线机加装无线遥控曝光及电子限时装置

利用移动式X线机进行床边摄片 ,在放射科投照工作中占一定的比重 ,F3 0 -3 0mA移动式X线机 ,采用手持机械限时器 ,控制曝光时间。我们体会到 ,此限时方式存在以下缺点 :①限时不精确 ,致使X线量不准 ,不利于提高照片质量 ,也不符合质量控制的标准化要求 ;②因为机器移动频繁 ,易人为损坏。我们采用无线遥控装置和JBS2 3 电子限时器加装在X线机上 ,经 2年使用 ,机器性能稳定 ,效果满意 ,可弥补以上缺陷 ,介绍如下。1　材料①选用上海无线电八厂生产的JBS2 3 限时器 1件 ;②上海无线电八厂生产的JTX型普通继电器 1只 ;③选用南京中和医…     

改良阴式全切术治疗非脱垂子宫的临床分析

目的探讨改良阴式全切术治疗非脱垂子宫的优点、手术要点、适应证及在基层医院的临床应用价值。方法对30例非脱垂子宫良性病变患者实施改良阴式全子宫切除术,与同期30例非脱垂子宫良性病变患者行经腹全子宫切除术进行对比研究。结果30例改良阴式全切者,无中转开腹、无盆腔脏器损伤,无1例发生术后尿潴留;两组术中出血、手术时间差异无显著性,阴式组排气时间,住院时间显著低于经腹组。结论改良阴式全子宫切除术具有手术时间短、创伤小、术后疼痛轻、并发症少、恢复快、住院时间短、腹部无瘢痕、费用低等优点,是在基层医院值得推广的理想术式。     

Contamination of 2-deoxy-2-[18F]fluoro-d-mannose in the 2-deoxy-2-[18F]fluoro-d-glucose preparations synthesized from [18F]acetyl hypofluorite and [18F]F2

The presence of 2-deoxy-2-[¹⁸F]fluoro-d-mannose ([¹⁸F]FDM) in 2-deoxy-2-[¹⁸F]fluoro-d-glucose ([¹⁸F]FDG) prepared by the reaction of 3,4,6-tri-O-acetyl-d-glucal (TAG) with [¹⁸F]acetyl hypofluorite ([¹⁸F]CH₃COOF) or [¹⁸F]F₂ was quantified by radio HPLC analysis of reacetylated [¹⁸F]FDG. The solvent effects on the stereoselectivity of the reaction of TAG with [¹⁸F]CH₃COOF were examined in six kinds of solvent.Reaction of TAG with [¹⁸F]CH₃COOF in Freon-11 results in the least contamination of [¹⁸F]FDM (4–5%). The presence of [¹⁸F]FDM in the [¹⁸F]FDG prepared from TAG with [¹⁸F]F₂ was also indicated, but by careful chromatographic separation of hexopyranosyl difluorides the amount was reduced to nearly that resulting from the [¹⁸F]CH₃COOF method.     

Improvement in PET myocardial perfusion image quality and quantification with flurpiridaz F 18

Rubidium-82 (⁸²Rb), the currently commercially available radiotracer for positron emission tomography (PET) myocardial perfusion imaging (MPI), has led to wide availability of PET-MPI for stress-rest imaging. Compared to SPECT MPI, myocardial perfusion PET images have higher spatial and contrast resolution, are less affected by radiotracer scatter, benefit from more precise attenuation correction, and allow dynamic first pass imaging. In addition, PET imaging allows assessment of myocardial function at peak stress and measurement of absolute myocardial blood flow, thus providing critical data not available with SPECT imaging. Further enhancements of the high quality of PET perfusion images may be realized by technologies under development such as respiratory gating, combined respiratory, and ECG gating to generate “motion-frozen” cardiac images, automated patient motion correction software, and high-definition PET, which reduces distortions introduced by the circular geometry of the scanner. Early studies indicate that the experimental PET radiopharmaceutical flurpiridaz F 18 provides high-quality, high-resolution myocardial perfusion images that may enable improved clinical MPI, and has properties well suited to optimized performance by application of these quantitative analytic technologies.     

Synthesis and tumour-localizing properties of [18F]-5-fluorocytosine-arabinoside and [18F]-5-fluorocyclocytidine

[¹⁸F]-5-fluorocytosine-arabinoside (2) and [¹⁸F]-5-fluorocyclocytidine (4) were prepared by reaction of [¹⁸F]-acetylhypofluorite with cytosine-arabinoside (1) or cyclocytidine (3) in acetic acid and were isolated in an overall radiochemical yield of 20% and 9%, respectively. The biodistribution of both radiopharmaceuticals was determined in melanoma bearing Syrian golden hamsters. It was found that 2 is a good tumour-localizing agent for pigmented and non-pigmented Greene melanoma.     

Synthesis and tumour-localizing properties of [18F]-5-fluorocytosine-arabinoside and [18F]-5-fluorocyclocytidine

[18F]-5-fluorocytosine-arabinoside (2) and [18F]-5-fluorocyclocytidine (4) were prepared by reaction of [18F]-acetylhypofluorite with cytosine-arabinoside (1) or cyclocytidine (3) in acetic acid and were isolated in an overall radiochemical yield of 20% and 9%, respectively. The biodistribution of both radiopharmaceuticals was determined in melanoma bearing Syrian golden hamsters. It was found that 2 is a good tumour-localizing agent for pigmented and non-pigmented Greene melanoma.     

Synthesis of 2-(1,1-dicyanopropen-2-yl)-6-(2-[18F]-fluoroethyl)-methylamino-naphthalene ([18F]FDDNP).

2-(1,1-dicyanopropen-2-yl)-6-(2-[18F]-fluoroethyl)-methylamino-naphthalene ([18F]FDDNP) was synthesized in a single step labeling procedure. The precursor, 2-(1,1-dicyanopropen-2-yl)-6-(2-tosyloxyoethyl)-methylamino-naphthalene, was fluorinated with 18F in acetonitrile. After 15 min the reaction mixture was subjected to preparative HPLC purification. The product was isolated from the HPLC eluent with solid-phase extraction, and formulated in an ascorbic acid solution to prevent formation of side products during formulation. Quantitative sticking to tubing and filters was overcome by the addition of polysorbatum-80. This formulation yielded an isotonic, pyrogen-free and sterile solution of [18F]FDDNP. The overall decay-corrected radiochemical yield was 41+/-11% (n=22). Radiochemical purity was >98% and the specific activity was 102+/-56 GBq/micromol at the end of synthesis.