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.     

Effects of Muslims praying (Salat) on EEG gamma activity

This study investigates the difference of mean gamma EEG power between actual and mimic Salat practices in twenty healthy Muslim subjects. In the actual Salat practice, the participants were asked to recite and performing the physical steps in all four stages of Salat; whereas in the mimic Salat practice, they were instructed to perform only the physical steps without recitation. The gamma power during actual Salat was statistically higher than during mimic Salat in the frontal and parietal regions in all stages. In the actual Salat practice, the left hemisphere exhibited significantly higher mean gamma power in all cerebral regions and all stages, except the central-parietal region in the sitting position, and the frontal area in the bowing position. Increased gamma power during Salat, possibly related to an increase in cognitive and attentional processing, supports the concept of Salat as a focus attention meditation.     

Oscillatory gamma and theta activity during repeated mental manipulations of a visual image

Previous studies on mental manipulation have dealt with direct manipulation of a presented stimulus or a maintained image of a previously presented stimulus. Here, we investigated brain activity differences between successive maintenance and manipulation of the visual stimulus and the once transformed representations using electroencephalography (EEG) in a multi-stage sequential manipulation task. The task required the subjects to memorize a presented object which possessed four features (color, shape, direction and speed of motion) and transform the feature of the representation twice. Wavelet analysis showed strong gamma-band (>30 Hz) activity elicited in the frontal and parietal regions during two successive mental manipulation tasks of the visual stimulus. Interestingly, gamma activity in the frontal and parietal regions was stronger during the second manipulation. Our results suggest that successive mental manipulations of the once transformed representation may impose higher demand on the fronto-parietal networks. On the other hand, while the frontal theta activity was enhanced throughout maintenance and manipulation periods, the activity during maintenance of one-time manipulated representation was higher than that of the physically presented stimulus, suggesting that the frontal regions are further recruited in maintenance of manipulated images.     

Study pharmacologic of the GABAergic and glutamatergic drugs on seizures and status epilepticus induced by pilocarpine in adult Wistar rats

This work was designed to study the influence of drugs during seizures and status epilepticus (SE) induced by pilocarpine and mortality in adult rats. Glutamate (10 and 20 mg/kg), N-methyl-d-aspartate (NMDA, 5 and 10 mg/kg), ketamine (1.5 and 2.0 mg/kg), gabapentin (200 and 250 mg/kg), phenobarbital (50 and 100 mg/kg) and vigabatrin (250 and 500 mg/kg) were administered intraperitoneally, 30 min prior to pilocarpine (400 mg/kg, i.p.). The animals were observed (24 h) to determine: number of peripheral cholinergic signs, tremors, stereotyped movements, seizures, SE, latency to first seizure and number of deaths after pilocarpine treatment. NMDA and glutamate had pro-convulsive effects in both doses tested. Smaller and higher doses of these drugs no protected and increased pilocarpine-induced seizures and/or mortality. Gabapentin, vigabatrin, phenobarbital and ketamine protected against seizures and increased the latency to first seizure. Thus, these results suggest that caution should be taken in the selection of pharmacotherapy and dosages for patients with seizures and SE because of the possibility of facility the convulsive process toxicity, SE and the mortality of adult animals in this seizures model that is similar temporal lobo epilepsy in humans.     

广西糖厂放射源应用辐射环境影响监测与评价

目的 掌握广西辖区内糖厂密封放射源的使用分布情况,评价密封放射源对周围环境、职业人员、公众成员产生的辐射影响,为今后糖厂放射源的使用管理提供科学依据。方法 按监测规范合理布点,利用γ辐射剂量率仪对广西区内所有使用密封放射源的糖厂开展辐射环境现场测量,根据监测结果进行估算,并结合个人剂量监测结果进行分析。结果 密封放射源使用场所周围辐射剂量率高于环境本底水平,职业人员、公众成员会受到一定的辐射剂量。结论 职业人员及公众成员年有效剂量结果符合相关要求。     

Fatal glioblastoma after Gamma Knife radiosurgery for arteriovenous malformation in a child

We describe a fatal case of glioblastoma multiforme that was induced by Gamma Knife radiosurgery (GKS; Elekta AB, Stockholm, Sweden) for an arteriovenous malformation (AVM). A 4-year-old girl presented with repeated convulsions. Imaging studies revealed an AVM located in the right thalamus. One year after initial symptoms, GKS was performed to obliterate the nidus. The maximum and marginal radiation doses were 32 and 16 Gy, respectively. Seventy months after GKS, the patient represented with severe headache. MRI showed a poorly demarcated tumor with heterogeneous gadolinium enhancement in the right thalamus and adjacent to the white matter of the temporal lobe. After a generalised convulsion, the patient deteriorated into a deep coma. CT scans showed severe brain swelling with intratumoral hemorrhage. An emergency craniotomy was performed, and the hematoma was removed. During this surgery, a tumor mass, which was found adjacent to the hematoma, was resected. Microscopic examination revealed glioblastoma multiforme. Despite intensive treatment, the patient died 1 month after surgery. A GKS-induced secondary tumor is a rare but serious complication. It is important to be aware of the adverse effects of GKS, including secondary neoplasms, before its clinical application, especially in young patients.     

伽玛刀治疗听神经瘤疗效观察

目的探讨伽玛刀治疗听神经瘤的疗效。方法应用玛西普伽玛刀治疗听神经瘤152例,其中84例获得完整随访资料,随访时间为12～89个月。结果肿瘤体积缩小57例（67．9％）、不变23例（27．3％）、增大4例。听力保留率为70．6％（36／51）,出现患侧面神经一过性受损4例（5．3％）,出现三叉神经功能受损症状3例（2例为一过性,1例经治疗后缓解）。结论伽玛刀治疗听神经瘤有较高的肿瘤生长控制率,对相关颅神经损伤小,并发症少,是一种安全有效的治疗方法。