Correction of frequency and phase variations induced by eddy currents in localized spectroscopy with multiple echo times.

As a consequence of the time-varying magnetic field induced by eddy currents, frequency drifting occurs when the sampling window of localized spectroscopy continuously shifts. The frequency drifting and the concomitant phase variations can severely affect spectroscopy results when data are acquired with multiple echo times (TEs), such as in the measurement of glutamate (Glu) concentration using the TE-averaged method. Specifically, the averaged spectra are further broadened and distorted in the presence of residual eddy currents, and editing of the coupled spins of Glu C4 protons is affected, resulting in errors in the measured relative intensity ratio. Postacquisition correction using unsuppressed water as reference can effectively minimize this detrimental effect, as manifested by the significantly enhanced signal intensity. Also, it is demonstrated that the methyl signals of creatine (Cr) at 3.0 ppm and choline (Cho) at 3.2 ppm can be used as internal references in finding frequency and phase disparities between different TEs.     

主动呼吸控制技术(ABC)在肺癌放射治疗中的应用

目的：使用主动呼吸控制技术（aetive brething control,ABC）治疗非小细胞肺癌患者，评价呼吸运动时肺部肿瘤动度的影响及ABC技术的优势和可行性，并评价近期疗效和急性放射反应。方法：选择9例使用ABC技术联合三维造型放疗技术治疗的非小细胞系癌患者进行分析。CT定位扫描时分别采集ABC和自由呼吸（free breath.FB）状态下的图像，评价呼吸运动对肺部肿瘤动度和PTV边界的影响唾弃；并比较两种计划的DVH，放疗剂量为54-60Gy/18-20次。3Gy/次，1次/天，5天/周，定期随访，评价近期疗效及急性放射反应。结果：应用ABC技术后，隔肌的平均位移从FB时的43.5mm（20.0-32.0mm）降低为3.6mm（0.5-72.mm）,胸壁的侧方位移从FB时的3.2mm（2.8-4.0mm）降低为1.2mm（0.5-1.6mm）.PTV边界可以从FB时的1.5mm减少为0.75cm;肺的V20从21.8%降低为15.0%,减少了30.6%.中位随访6个月时,9例患者中有6例CR,3例PR.急性放射副反应都很轻微,仅为I-II.结论：在肺癌的精确放射治疗中,呼吸动度的影响不可忽视.而ABC系统可以有效的降低呼吸运动时治疗的影响,提高放疗的精确性,减少副反应.,但该系统使用较为复杂,延长了治疗的时间,个别患者不能忍受.     

166Ho-DOTMP radiation-absorbed dose estimation for skeletal targeted radiotherapy.

166Ho-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene-phosphonate (DOTMP) is a tetraphosphonate molecule radiolabeled with 166Ho that localizes to bone surfaces. This study evaluated pharmacokinetics and radiation-absorbed dose to all organs from this beta-emitting radiopharmaceutical. METHODS: After two 1.1-GBq administrations of 166Ho-DOTMP, data from whole-body counting using a gamma-camera or uptake probe were assessed for reproducibility of whole-body retention in 12 patients with multiple myeloma. The radiation-absorbed dose to normal organs was estimated using MIRD methodology, applying residence times and S values for 166Ho. Marrow dose was estimated from measured activity retained after 18 h. The activity to deliver a therapeutic dose of 25 Gy to the marrow was determined. Methods based on region-of-interest (ROI) and whole-body clearance were evaluated to estimate kidney activity, because the radiotracer is rapidly excreted in the urine. The dose to the surface of the bladder wall was estimated using a dynamic bladder model. RESULTS: In clinical practice, gamma-camera methods were more reliable than uptake probe-based methods for whole-body counting. The intrapatient variability of dose calculations was less than 10% between the 2 tracer studies. Skeletal uptake of 166Ho-DOTMP varied from 19% to 39% (mean, 28%). The activity of 166Ho prescribed for therapy ranged from 38 to 67 GBq (1,030-1,810 mCi). After high-dose therapy, the estimates of absorbed dose to the kidney varied from 1.6 to 4 Gy using the whole-body clearance-based method and from 8.3 to 17.3 Gy using the ROI-based method. Bladder dose ranged from 10 to 20 Gy, bone surface dose ranged from 39 to 57 Gy, and doses to other organs were less than 2 Gy for all patients. Repetitive administration had no impact on tracer biodistribution, pharmacokinetics, or organ dose. CONCLUSION: Pharmacokinetics analysis validated gamma-camera whole-body counting of 166Ho as an appropriate approach to assess clearance and to estimate radiation-absorbed dose to normal organs except the kidneys. Quantitative gamma-camera imaging is difficult and requires scatter subtraction because of the multiple energy emissions of 166Ho. Kidney dose estimates were approximately 5-fold higher when the ROI-based method was used rather than the clearance-based model, and neither appeared reliable. In future clinical trials with 166Ho-DOTMP, we recommend that dose estimation based on the methods described here be used for all organs except the kidneys. Assumptions for the kidney dose require further evaluation.     

Caudate nucleus volume and cognitive performance: Are they related in childhood psychopathology?

BACKGROUND: Impaired neuropsychological test performance, especially on tests of executive function and attention, is often seen in children diagnosed with autism spectrum disorders (ASD). Structures involved in fronto-striatal circuitry, such as the caudate nucleus, may support these cognitive abilities. However, few studies have examined caudate volumes specifically in children with ASD, or correlated caudate volumes to cognitive ability. METHODS: Neuropsychological test scores and caudate volumes of children with ASD were compared to those of children with bipolar disorder (BD) and of typically developing (TD) children. The relationship between test performance and caudate volumes was analyzed. RESULTS: The ASD group displayed larger right and left caudate volumes, and modest executive deficits, compared to TD controls. While caudate volume inversely predicted performance on the Wisconsin Card Sorting Test in all participants, it differentially predicted performance on measures of attention across the ASD, BD and TD groups. CONCLUSIONS: Larger caudate volumes were related to impaired problem solving. On a test of attention, larger left caudate volumes predicted increased impulsivity and more omission errors in the ASD group as compared to the TD group, however smaller volume predicted poorer discriminant responding as compared to the BD group.     

变温培养对泰乐菌素发酵的影响

在泰乐菌素发酵过程中的不同阶段采用不同的培养温度,通过实验考察其对泰乐菌素发酵的影响。实验结果表明,变温培养的发酵水平要高于其它恒温培养的发酵水平。     

The Web of Internet Dependency: Search Results for the Mental Health Professional

Some researchers speculate that as many as 10% of users worldwide suffer from “problematic” use of the internet, possibly stemming from an internet dependency. Research is in its early stages, making it an uncertain issue for mental health professionals. This paper provides: (1) a critical review of research on problematic internet use for the mental health and addictions professional; and (2) practical implications, including suggestions on treatment and prevention, given its uncertain clinical classification.     

4110例肝炎分型分析

[目的]探讨各型肝炎的感染率。[方法]研究对象为我院住院及门诊患者，共计4110例。采用微粒子酶免分析法（MEIA）及酶联免疫吸附法（ELISA）进行肝炎分型（甲、乙、丙、丁、戊、庚肝）检测。[结果]4110例受检者中，单纯乙肝感染者133例，占3．24％；单纯丙肝感染者134例，占3．26％；单纯戊肝感染者2例，占0．05％；乙肝合并丙肝感染者3例，占0．07％；丙肝合并戊肝感染者1例，占0．02％；HAV、HDV、HGV无一例感染，感染率为0。另外，男性受检者2088人，乙肝感染者88人，占4．21％；丙肝感染者48人，占2．30％；女性受检者2022人，乙肝感染45人，占2．23％；丙肝感染86人，占4．25％。[结论]除丙肝外，各型感染率均低于全国平均感染率，与相关资料报道相差甚远。乙肝及丙肝仍以单纯感染多见。另，本组资料还显示，男性较女性更易感染乙肝病毒，而女性感染丙肝者远远高于男性，对于丙肝感染的性别差异，尚无报道，需进一步探讨。