鞍旁靶病灶X—刀治疗剂量分布的实验研究

通过仿真人体模模拟鞍旁靶病灶Ｘ－刀照射，探讨照射方式对剂量分布的影响。结果表明，避免射线束直接投照视神经、视交叉和脑干是减少治疗后并发症的关键技术之一，增加照射弧的度数将明显改善剂量分布。Ｘ－刀是鞍旁肿瘤富有吸引力的治疗手段。     

X—刀治疗垂体腺瘤的方法及疗效评价

目的 探讨Ｘ－刀治疗垂体腺瘤的临床价值。方法 采用德国ＢｒａｉｎＳｃａｎＸ刀治疗系统治疗了垂体腺瘤病人３５例，肿周边剂量平均为１２．３２Ｇｙ，视神经和视交叉的最大照射剂量小于８￣１０Ｇｙ，治疗后每三个月随访一次ＣＴ和激素检查，所有病例随访时间均１年以上。     

X-刀治疗颅内疾患26例报告

Ｘ－刀治疗颅内疾患２６例报告徐培坤，李汉杰，陈功达，余永强，高世明Ｘ－刀作为立体定向放射外科的重要部分，近１０多年来发展很快。它和γ－刀相比，其优点在于能够治疗较大体积病灶；可行分次治疗；能使剂量分布最大限度地与病灶形态相一致。作者总结２６例Ｘ－刀治...     

微型多叶光栅系统与传统X—刀系统的比较

目：颅内病灶常常是不规则的或体积较大，传统Ｘ－刀系统需采用多个等中心达到覆盖靶灶的目的，但使靶灶内剂量分布不均一，而且计划、治疗难。本文比较了微型多叶光栅系统与传统Ｘ－刀系统在剂量分布上的不同。材料和方法：取颅内球形、不规则形病灶、分别使用微型多叶光栅系统与传统Ｘ－刀系统制定治疗计划，通过DVH、RTOG的放射外科指标coverage,HI,CI进行计划评价。结果：从DVH和RTOG的3项指标表明，对于小球形靶灶，微型多叶光栅系统与传统X－刀系统差别不大；不规则形病灶，微型多叶光栅系统比传统X－刀系统更有优势，使用5－7个射束即可以有较好的剂量分布。结论：微型多叶光栅系统作为直线加速器放射外科的一种方法，比传统X－刀系统有更好的剂量分布，靶灶内部剂量均匀，剂量线适形好，并且计划、治疗简单。     

颅内肿瘤X-刀治疗近期疗效观察

目的：探讨Ｘ－刀对颅内肿瘤的治疗作用。方法：观察Ｘ－刀治疗９３例颅内肿瘤患者的近期治疗效果。７１例得到随访，平均随访４．６５月。结果：肿瘤局部控制率９６．３０％，病情稳定好转率８０．３０％。大病灶和小病灶的肿瘤控制率相近，但大病灶术后脑组织反应多而严重，患者的生存质量也差。结论：Ｘ－刀对颅内肿瘤有肯定治疗作用，严格选择病变大小，正确选择限光筒、照射弧和剂量，合理使用低剂量分次治疗是减少并发症，提高疗效的有效措施     

X刀分次照射头环的研制

Ｘ刀分次照射头环的研制陈超敏周凌宏于晓宝陈运钦Ｘ刀是立体定向放射外科治疗系统的俗称，它是利用直线加速器的Ｘ射线进行立体定向放射外科治疗的系统。通过直线加速器机架的旋转和治疗床角度的变化，使受照射的靶区始终接受高剂量的Ｘ射线，靶区周围Ｘ线的放射剂量呈锐...     

关于X-刀治疗的照射剂量

关于Ｘ－刀治疗的照射剂量王所亭张纪陈国雄自立体定向放射外科（ＳＲＳ）技术（Ｘ，γ刀）问世以来，由于它使用了与常规放疗根本不同的单次特大剂量，那么“究竟该用多大剂量”一直受人关注。由于对此涉及到的因素很多，不能一概而论，但也并非无规律可循。本文拟通过国...     

颅内肿瘤X—刀治疗近期疗效观察

目的：探讨Ｘ－刀地颅内肿瘤的治疗作用。方法：观察Ｘ－刀治疗９３例颅内肿瘤患者的近期治疗效果。７１例得到随访，平均随访４．６５月。结果：肿瘤局部控制率９６．３０％，病情稳定好转率８０．３０％。大病灶和小病灶的肿瘤控制率相近，但大病灶术后脑组织反应多而严重，患者的生存质量差。结论：Ｘ－刀对颅内肿瘤有肯定治疗作用，严格选择病变大小，正确选择限光筒、照射弧和剂量，合理使用低剂量分次治疗是减少并发症，提高疗     

X-刀治疗144例患者的配合及护理

Ｘ－刀治疗１４４例患者的配合及护理严利春李开慧本文总结１４４例颅脑疾病患者行Ｘ－刀治疗术前、术中、术后的配合及护理。重点应放在心理护理和对一次大剂量聚焦照射后急性反应的观察和护理，指出护理人员不仅要有扎实的护理理论基础和熟练的专科技能，而且还应具备相...     

微型多叶光栅系统与传统X-刀系统的比较

目的：颅内病灶常常是不规则的或体积较大,传统Ｘ－刀系统需采用多个等中心达到覆盖靶灶的目的,但使靶灶内剂量分布不均一,而且计划、治疗难。本文比较了微型多叶光栅系统与传统Ｘ－刀系统在剂量分布上的不同。材料和方法：取颅内球形、不规则形病灶,分别使用微型多叶光栅系统与传统Ｘ－刀系统制定治疗计划,通过ＤＶＨ,ＲＴＯＧ的放射外科指标ｃｏｖｅｒａｇｅ,ＨＩ,ＣＩ进行计划评价。结果：从ＤＶＨ和ＲＴＯＧ的３项指标表明,对于小球形靶灶,微型多叶光栅系统与传统Ｘ－刀系统差别不大;不规则形病灶,微型多叶光栅系统比传统Ｘ－刀系统更有优势,使用５－７个射束即可以有较好的剂量分布。结论：微型多叶光栅系统作为直线加速器放射外科的一种方法,比传统Ｘ－刀系统有更好的剂量分布,靶灶内部剂量均匀,剂量线适形好,并且计划、治疗简单。     

Hepatic Considerations in the Use of Antiepileptic Drugs

Summary: Virtually all of the major antiepileptic drugs (AEDs) can cause hepatotoxicity, although fatal hepatic reactions are rare. The mechanisms, incidences, and risk profiles for such reactions differ from drug to drug. With carbamazepine and phenytoin, hepatotoxicity may be due to drug hypersensitivity. Although the profiles of patients at risk have not been well-defined for these two antiepileptic drugs, it would appear from reports in the literature that older adolescents and adults are at higher risk than children of developing serious or fatal hepatotoxicity. Once hepatotoxicity develops, mortality rates are 10–38% with phenytoin and 25% for carbamazepine. The risk profile for valproate fatal hepatotoxicity has been more clearly defined. Those at primary risk of fatal hepatic dysfunction are children under the age of 2 years who are receiving multiple anticonvulsants and also have significant medical problems in addition to severe epilepsy. The risk is considerably lower for patients over the age of 2 years on valproate monotherapy. In contrast to the risk profile with other AEDs, adults receiving valproate as monotherapy have the lowest risk of hepatotoxicity. Fatal hepatic dysfunction coincident with valproate may be the result of aberrant drug metabolism. Concomitant use of AEDs that induce microsomal P450 enzymes (e.g., phenytoin and phenobarbital) may enhance the production of a toxic metabolite, and hence the greater risk of hepatotoxicity with polypharmacy.     

Vascular Malformations and Epilepsy: Clinical Considerations and Basic Mechanisms

Summary: Vascular malformations (VMs) are associated with epilepsy. The natural history of the various VMs, clinical presentation, and tendency to provoke epilepsy determine treatment strategies. Investigations have probed the mechanisms of epileptogenesis associated with these lesions. Electrophysiologic changes are associated with epileptogenic cortex adjacent to VMs. Putative pathophysiologic mechanisms of epileptogenesis include neuronal cell loss, glial proliferation and abnormal glial physiology, altered neurotransmitter levels, free radical formation, and aberrant second messenger physiology.     

Diagnostic Difficulties and Treatment Implications

Summary: Differentiation between types of epileptic seizures has been aided in recent years by the introduction of intensive neurodiagnostic techniques and the development of increasingly detailed classification systems. Paradoxically, these developments have not simplified the task of matching the appropriate antiepileptic drug to a particular seizure type. It is reasonable to assume that anticonvulsant drugs will have different effects on different types of seizures, but faulty, circular reasoning can enter the picture if one also assumes that responses of seizures to different drugs signify different seizure types. There are several examples of differential diagnoses that can fall prey to this problem, including the diagnosis between partial seizures with secondary generalization and generalized tonic-clonic seizures, and the diagnosis between complex partial seizures and absence seizures with automatisms, among others. Considerations of etiology in future classification systems can further complicate the problem: should one then choose an anticonvulsant drug on the basis of individual seizure type or on the basis of the type of epilepsy? Ramifications of this issue extend even to the drug approval process. Official sanction is not given for use of a drug for a seizure type not included in the original efficacy studies, even if later scientific evidence shows that seizure type to be related to a type that is included. New trials must be undertaken. These problems arise from how we choose to classify seizures.     

Cognitive Dysfunction Associated with Antiepileptic Drug Therapy

Summary: Epilepsy is frequently associated with cognitive dysfunction. However, the reasons for this correlation are unclear. Possible influential factors include patient age; duration, frequency, etiology, and type of seizures; hereditary factors; psychosocial issues; and antiepileptic drug (AED) therapy. Whereas many of these factors are beyond the physician's control, AED therapy is one element that can be addressed in treatment decisions by recognizing the potential cognitive effects of particular AEDs. For example, phenobarbital impairs memory and concentration; phenytoin affects attention, problem solving ability, and performance of visuomotor tasks. In contrast, carbamazepine may affect concentration, while valproate would appear to have minimal effects on cognition. Moreover, cognitive effects of AEDs are amplified with coadministration of multiple anticonvulsants (polytherapy). A review of studies on the cognitive effects of monotherapy with AEDs, as opposed to those of polytherapy, provides evidence that drug-related cognitive dysfunction can be reversed if patients are switched to a simpler therapeutic regimen. Future research should be directed toward developing reliable measures for assessing and monitoring cognition, and understanding the particular cognitive side effects of each AED. Physicians also need to revise their opinions about which side effects are "tolerable" for epileptic patients.     

Epilepsy and anomalies of neuronal migration: MRI and clinical aspects

Neuronal migration disorders are the result of disturbed brain development. In such disorders, neurons are abnormally located. In diagnosing these conditions, magnetic resonance imaging is superior to any other imaging technique. This enables us to improve our knowledge of the clinical correlates of neuronal migration. With reference to migrational disorder, a retrospective study of all 303 patients with epileptic seizures referred for magnetic resonance imaging during a 3-year period was performed, 13 patients (aged 12-41, mean age 27) were identified. They represent 4.3% of the entire study group. Of the patients with known epilepsy, 6.7% and of the mentally retarded, 13.7% had migrational disorders. Four patients had schizencephaly as the dominant finding, one was classified as hemimegalencephaly, 2 had isolated heterotopias, and 6 had localized pachy- and/or poly-microgyria. The clinical pictures are complex. Ectopias of grey matter are recognised foci of epilepsy, but from an epileptological and a clinical viewpoint little attention has been given to these disorders. The present study shows that malmigration is not rare in epilepsy patients, especially not in the mentally retarded.     

Carbamazepine Efficacy and Utilization in Children

Summary: Carbamazepine is effective for preventing partial and generalized tonic-clonic seizures in children. Although absence epilepsies are more common in children than adults, an estimated 80% of children with epilepsy have seizure types or epilepsies that are potentially responsive to carbamazepine. The differential diagnosis of ictal staring is an especially important issue in children because absence and atypical absence seizures are more prevalent in children than adults. Age-related pharmacokinetic differences and drug interactions are major considerations in children. On average, children have higher clearance rates of carbamazepine, shorter half-lives, and higher ratios of carbamazepine-10, 11-epoxide to carbamazepine than adults. In addition, children with severe epilepsy are more likely to require multiple-drug therapy, which can lead to complex drug interactions. When carbamazepine is administered along with valproate, drug protein binding interactions can cause intermittent side effects.     

Carbamazepine Efficacy in Adults With Partial and Generalized Tonic-Clonic Seizures

Summary: Carbamazepine and phenytoin are drugs of choice in initial monotherapy for adult partial and secondarily generalized tonic-clonic seizures. These designations reflect the results of the Veterans Administration Epilepsy Cooperative Study Group of 1985. An earlier comparative study of carbamazepine and phenytoin by Ramsay and associates found both drugs equally effective in controlling new-onset seizures. Among the advantages of carbamazepine is that it causes relatively few cognitive and dysmorphic side effects. Its disadvantages are its unavailability in parenteral formulation and its metabolic autoinduction. The latter must be compensated for by planned dosage increases to maintain therapeutic plasma steady-state levels during the first 2 or 3 months of treatment. Carbamazepine is judged a drug of choice in the treatment of these secondarily generalized tonic-clonic seizures, and the drug of choice in children, adolescents, and women susceptible to the dysmorphic side effects associated with other anticonvulsant agents.     

Etiologic and Preventive Aspects of Epilepsy in the Child–Bridging the Gap Between Laboratory and Clinic

Summary: Four broad categories of basic phenomena are pertinent to developing ways to prevent epilepsy. These include mechanisms of epileptogenesis, ictal initiation and temporary entrainment by the seizure discharge of normally functioning brain, seizure propagation, and control mechanisms that function both to restrain the cascade of epileptic events culminating in a seizure and to arrest the epileptic event and restore the interictal state. In newborns and children, hypoxia-ischemia is a major factor leading to epileptogenesis, and several schemes are proposed to classify, quantify, and prevent hypoxic-ischemic encephalopathy. Control mechanisms must be better understood in order to develop prophylactic recommendations for epilepsy, and an experimental model of "kindling antagonism" may increase our understanding of these. Programs of prevention of seizures in children will evolve only if basic researchers and clinicians work productively together to develop an adequate understanding of factors important in epileptogenesis and antiepileptogenic control mechanisms.     

Predisposing and Causative Factors in Childhood Epilepsy

Summary: We review information from large studies of defined populations, examining the role of known factors and especially of prenatal and perinatal factors in contributing to nonfebrile seizure disorders of early childhood. We depend especially, but not exclusively, on the recently completed analyses from the Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke, the NCPP. About 4% of children in the NCPP who had at least one non-febrile nonsymptomatic seizure by the age of 7 years had a previous seizure during acute neurologic illness, such as meningitis or during the acute illness after trauma. Many such seizures should potentially be preventable. Of children with seizures, 10% had had a neonatal seizure and 13% had had a febrile seizure. Among the hundreds of prenatal and perinatal factors explored as predictors of childhood seizure disorders, the principal predictors identified were congenital malformations of the fetus, cerebral and noncerebral; family history of certain neurologic disorders; and neonatal seizures. In agreement with the British National Child Development Study, labor and delivery factors in the NCPP appeared to contribute very little to childhood seizure disorders. Maldevelopment, rather than damage at birth to an initially intact nervous system, appeared to be the more common mechanism. Most seizure disorders of early childhood remained unexplained by the large set of prenatal and perinatal characteristics examined.     

Treatment Considerations in Anticonvulsant Monotherapy

Summary: The long-standing practice of polypharmacy in treating epilepsy is giving way to use of monotherapy. Monotherapy can improve seizure control as well as reduce the risk of serious idiosyncratic reactions, dose-related side effects, and complex drug interactions. Monotherapy also offers improved compliance and cost-effectiveness. The basis of monotherapy is accurate diagnosis and assessment of the patient's seizure type(s), followed by selection of a single appropriate anticonvulsant drug. Many patients currently treated with multiple anticonvulsants can be successfully converted to monotherapy with a carefully monitored program in which troublesome and redundant drugs are gradually withdrawn from the therapeutic regimen.