Cranial suture simulator for ultrasound diagnosis of craniosynostosis

Background: In evaluating the effectiveness of ultrasound as a screening tool for craniosynostosis it was discovered that sonologists and sonographers needed more experience scanning and visualizing cranial sutures on ultrasound. Objective: To create an ultrasound simulator to train radiologists and technologists to locate and recognize patent and fused cranial sutures in children. Materials and methods: The hypoechoic appearance of patent sutures was simulated by cutting lines into life-sized plastic doll heads and filling them with a commercial hypoechogenic material. Fused hyperechoic sutures were simulated by not cutting into the hard plastic region of a suture. The simulators teaching value was evaluated on three radiology residents and three fellows. Subjects performed pre-training scans on unknown simulators, received feedback and an opportunity to scan a training simulator, and then performed post-training scans on random unknown simulators. Accuracy was recorded as percentage of correctly demonstrated sutures. Results: The suture simulator reproduces the sonographic appearance of patent and fused cranial sutures. Accuracy of acquisition, interpretation, and overall diagnosis increased from 64 to 91%, 79 to 91%, 61 to 97%, respectively, between pre and post training scans. Conclusion: An ultrasound simulator can reproduce the appearance of patent and fused cranial sutures in children and can be used to train radiologists and technologists in the performance of a screening protocol.     

Tissue-mimicking materials for teaching sonographers and evaluation of their specifications after three years

In this paper, an algorithm is introduced for making breast phantoms and abnormal masses (cyst, fibroadenoma and cancer). The evaluation of ultrasonic properties (sound velocity and amplitude attenuation coefficient) of these normal breast phantoms and abnormal masses and their ultrasonic images shows that they are stable over 3 years. The measurement and evaluation results of ultrasonic images of our phantoms show that they behave like human breast tissues. Practicing with these phantoms for developing fine-needle aspiration (FNA) skills in sonographers shows that these phantoms reduce the time required for successful FNA. The ultrasonic phantoms have different ultrasonic applications, including ultrasonic medical imaging, the quality control of ultrasound (US) instruments, processing technique evaluation and US training; moreover, they are stable in room temperature and can keep their specifications for more than 3 years. (E-mail: Mokhtarm@modares.ac.ir)     

大转子髋关节融合术治疗全(半)髋关节置换后假体松动

目的:探讨针对人工全(半)髋关节置换术后因假体松动而采取补救性的关节融合手术的适应症与禁忌症。方法:6例人工全(半)髋关节置换术后假体松动的患者应用大转子髋关节融合术予以治疗。结果:经术后12~36个月,平均16个月随访,X线片示髋关节均获骨性融合,融合时间为5~8个月,平均6.5个月。Harris髋关节评分由术前的26~41分,平均31分,提高到术后56~80分,平均72分。结论:本手术是一种疗效可靠、简单实用、切实可行的补救性治疗方法。     

幻肢痛

幻肢现象不仅局限于四肢,身体其他部位被切除时也会发生,其中幻肢痛的发生率约占60%～70%。最近,其发病机制中大脑皮层功能重组和幻肢感、幻肢痛的相关性受到重视,认为很可能是幻肢痛产生的中枢性机制之一。幻肢痛的治疗极为困难,治疗方式多种多样,被证明行之有效的包括药物治疗、神经阻滞治疗、外科治疗、心理疗法等。治疗方案仍然没有统一和定论。     

双能CT在增强检查中的应用:体模研究

目的 探讨双能CT(DECT)成像技术在增强检查中的应用价值.方法 将浓度不同的碘乙醇溶液和碘水溶液封装于塑料试管中,按顺序固定后浸浴在装满水的截面近似椭圆、周长为86 cm的尼龙复合膜中制成体模原型.于Siemens Somatom Definition Flash扫描仪分别采用常规上腹部条件进行单能和DECT扫描.于专用图像工作站采用Liver VNC软件测量各溶液的碘浓度,并回顾性重建权重为0.5的线性混合图像、最优非线性混合图像(OCM)和CNR最大的单能量图像.结果 两种溶液碘浓度测量值与理论值均呈强相关(r=0.998、0.999,P均 <0.001),但相对误差较大(最大值25.00%).OCM图像和65 keV单能量图像的CNR碘浓度比均显著高于120 kVp图像(P <0.001).结论 DECT可准确区分不同碘溶液的浓度,应用于增强检查可提高图像质量.     

一种低成本、高仿真的自制模型用于超声引导下甲状腺细针穿刺住院医师培训

目的超声引导下甲状腺细针穿刺是诊断甲状腺结节良恶性的一种准确的方法。因为缺少廉价、高仿真的模型,所以绝大多数住院医师都没有在模型上进行充分的练习。笔者的目的是制作一个低成本、高仿真的模型用于住院医师的培训。 方法魔芋、明胶、玉米淀粉、试管、鱼油胶囊等经过简单的过程制作成一个高仿真的模型。20名超声专业的住院医师参加了甲状腺细针穿刺的培训,并在培训前后填写了问卷调查。 结果该模型成功、逼真地模拟了甲状腺解剖和超声声像图。所有参加训练的住院医师均认为这个培训课程有价值。调查的问题均有显著的提高。对技术的信心显著提高,而焦虑明显降低。 结论这个魔芋-明胶模型是一个用于超声引导下甲状腺结节细针穿刺住院医师培训的低成本、高仿真的模型。     

Neuroimaging the pain network – Implications for treatment

In this chapter, we provide an overview of neuroimaging studies in chronic pain. We start with an introduction about the phenomenology of pain. In the following section, the application of functional and structural imaging techniques is shown in selected chronic pain syndromes (chronic back pain, fibromyalgia syndrome (FMS), phantom limb pain, and complex regional pain syndrome (CRPS)), and commonalities and peculiarities of imaging correlates across different types of chronic pain are discussed. We conclude this chapter with implications for treatments, with focus on behavioral interventions, sensory and motor trainings, and mirror and motor imagery trainings.     

A phantom study of the accuracy of CT, MR and PET image registrations with a block matching-based algorithm

PURPOSE: The aim of the present study was to quantitatively assess the performance of a block matching-based automatic registration algorithm integrated within the commercial treatment planning system designated ISOgray from Dosisoft. The accuracy of the process was evaluated by a phantom study on computed tomography (CT), magnetic resonance (MR) and positron emission tomography (PET) images. MATERIALS AND METHODS: Two phantoms were used to carry out this study: the cylindrical Jaszczak phantom and the anthropomorphic Liqui-Phil Head Phantom (the Phantom Laboratory), containing fillable spheres. External fiducial markers were used to quantify the accuracy of 41 CT/CT, MR/CT and PET/CT automatic registrations with images of the rotated and tilted phantoms. RESULTS: The study first showed that a cylindrical phantom was not adapted for the evaluation of the performance of a block matching-based registration software. Secondly, the Liqui-Phil Head Phantom study showed that the algorithm was able to perform automatic registrations of CT/CT and MR/CT images with differences of up to 40 degrees in phantom rotation and of up to 20-30 degrees for PET/CT with accuracy below the image voxel size. CONCLUSION: The study showed that the block matching-based automatic registration software under investigation was robust, reliable and yielded very satisfactory results. This phantom-based test can be integrated into a periodical quality assurance process and used for any commissioning of image registration software for radiation therapy.     

The determination of phantom and collimator scatter components of the output of megavoltage photon beams: measurement of the collimator scatter part with a beam-coaxial narrow cylindrical phantom

The separation of the total scatter correction factor S_{c, p} in a collimator scatter component, S_c, and a phantom scatter component, S_p, has proven to be an useful concept in megavoltage photon beam dose calculations in situations which differ from the standard treatment geometry. A clinically applicable method to determine S_c is described. Measurements are carried out with an ionization chamber, placed at a depth beyond the range of contaminant electrons, in a narrow cylindrical polystyrene phantom with a diameter of 4 cm of which the axis coincides with the beam axis. S_{c, p} is measured in a full-scatter phantom and S_p can be derived from S_{c, p} and S_c. In order to obtain a reliable separation, i.e. excluding the influence of contaminant electrons, measurements of S_{c, p} have been carried out at depths of 5 cm for photon beams with a quality index (QI) up to and including 0.75 and a depth of 10 cm with QI larger than 0.75. These depths are in accordance with recommendations given in recent dosimetry protocols. The consistency of the method was checked by comparing calculated and measured values of S_{c, p} for a set of blocked fields for a range of photon beam energies from ⁶⁰Co up to 25 MV showing a maximum deviation of 2%. The method can easily be implemented in existing procedures for the calculation of the number of monitor units to deliver a specified dose to a target volume.     

Estimating the absorbed dose to critical organs during dual X-ray absorptiometry.

OBJECTIVE: The purpose of this study is to estimate a patient's organ dose (effective dose) during performance of dual X-ray absorptiometry by using the correlations derived from the surface dose and the depth doses in an anthropomorphic phantom. MATERIALS AND METHODS: An anthropomorphic phantom was designed and TLDs (Thermoluminescent Dosimeters) were placed at the surface and these were also inserted at different depths of the thyroid and uterus of the anthropomorphic phantom. The absorbed doses were measured on the phantom for the spine and femur scan modes. The correlation coefficients and regression functions between the absorbed surface dose and the depth dose were determined. The derived correlation was then applied for 40 women patients to estimate the depth doses to the thyroid and uterus. RESULTS: There was a correlation between the surface dose and depth dose of the thyroid and uterus in both scan modes. For the women's dosimetry, the average surface doses of the thyroid and uterus were 1.88 microGy and 1.81 microGy, respectively. Also, the scan center dose in the women was 5.70 microGy. There was correlation between the thyroid and uterus surface doses, and the scan center dose. CONCLUSION: We concluded that the effective dose to the patient's critical organs during dual X-ray absorptiometry can be estimated by the correlation derived from phantom dosimetry.