Studying Factors Affecting Indoor Gamma-radiation Dose using Mcnp5 Simulation Software-revisited: Adding Two More Factors.

The main factors that affect the gamma-radiation dose rate inside a room are defined in a simulation model. Some previously studied factors are the point of detection inside the room, the dimensions of the room, the thicknesses of the different parts of the room, and the density of the building material. The model is meant to ease the dose-rate estimation. Relative dose rates are calculated for different values of the different factors. The calculations are made using Monte Carlo n-particle simulation software. In this study two new factors are being added: the existence of a neighboring room and the split of a wall into two portions.

Studying factors affecting the indoor gamma radiation dose using the MCNP5 simulation software.

Different factors and parameters affecting the indoor gamma radiation dose are considered and investigated. The change of the dose with different positions inside the room is discussed. The relative doses are also calculated for different changes; with different room dimensions, different wall thicknesses, and different building material densities. Some other factors are also discussed. The study is carried out by executing some models designed by the MCNP version 5 simulation software. The calculations of the dose rates are performed by adopting a simple and convenient calculation model which is based on the obtained relative changes of the dose rates with the different factors.

[Chordoma]. / Les chordomes.

PURPOSES: To review in the literature, all the epidemiological, clinical, radiological, histological and therapeutic data regarding chordomas as well as various notochordal entities: ecchordosis physaliphora, intradural and intraparenchymatous chordomas, benign notochordal cell tumors, parachordomas and extra-axial chordomas. To identify different types of chordomas, including familial forms, associations with tuberous sclerosis, Ollier's disease and Maffucci's syndrome, forms with metastasis and seeding. To assess the recent data regarding molecular biology and progress in targeted therapy. To compare the different types of radiotherapy, especially protontherapy and their therapeutic effects. To review the largest series of chordomas in their different localizations (skull base, sacrum and mobile spine) from the literature. MATERIALS: The series of 136 chordomas treated and followed up over 20 years (1972-2012) in the department of neurosurgery at Lariboisière hospital is reviewed. It includes: 58 chordomas of the skull base, 47 of the craniocervical junction, 23 of the cervical spine and 8 from the lombosacral region. Similarly, 31 chordomas in children (less than 18 years of age), observed in the departments of neurosurgery of les Enfants-Malades and Lariboisière hospitals, are presented. They were observed between 1976 and 2010 and were located intracranially (n=22 including 13 with cervical extension), 4 at the craniocervical junction level and 5 in the cervical spine. METHODS: In the entire Lariboisière series and in the different groups of localization, different parameters were analyzed: the delay of diagnosis, of follow-up, of occurrence of metastasis, recurrence and death, the number of primary patients and patients referred to us after progression or recurrence and the number of deaths, recurrences and metastases. The influence of the quality of resection (total, subtotal and partial) on the prognosis is also presented. Kaplan-Meier actuarial curves of overall survival and disease free survival were performed in the entire series, including the different groups of localization based on the following 4 parameters: age, primary and secondary patients, quality of resection and protontherapy. In the pediatric series, a similar analysis was carried-out but was limited by the small number of patients in the subgroups. RESULTS: In the Lariboisière series, the mean delay of diagnosis is 10 months and the mean follow-up is 80 months in each group. The delay before recurrence, metastasis and death is always better for the skull base chordomas and worse for those of the craniocervical junction, which have similar results to those of the cervical spine. Similar figures were observed as regards the number of deaths, metastases and recurrences. Quality of resection is the major factor of prognosis with 20.5 % of deaths and 28 % of recurrences after total resection as compared to 52.5 % and 47.5 % after subtotal resection. This is still more obvious in the group of skull base chordomas. Adding protontherapy to a total resection can still improve the results but there is no change after subtotal resection. The actuarial curve of overall survival shows a clear cut in the slope with some chordomas having a fast evolution towards recurrence and death in less than 4 years and others having a long survival of sometimes more than 20 years. Also, age has no influence on the prognosis. In primary patients, disease free survival is better than in secondary patients but not in overall survival. Protontherapy only improves the overall survival in the entire series and in the skull base group. Total resection improves both the overall and disease free survival in each group. Finally, the adjunct of protontherapy after total resection is clearly demonstrated. In the pediatric series, the median follow-up is 5.7 years. Overall survival and disease free survival are respectively 63 % and 54.3 %. Factors of prognosis are the histological type (atypical forms), localization (worse for the cervical spine and better for the clivus) and again it will depend on the quality of resection. CONCLUSIONS: Many different pathologies derived from the notochord can be observed: some are remnants, some may be precursors of chordomas and some have similar features but are probably not genuine chordomas. To-day, immuno-histological studies should permit to differentiate them from real chordomas. Improving knowledge of molecular biology raises hopes for complementary treatments but to date the quality of surgical resection is still the main factor of prognosis. Complementary protontherapy seems useful, especially in skull base chordomas, which have better overall results than those of the craniocervical junction and of the cervical spine. However, we are still lacking an intrinsic marker of evolution to differentiate the slow growing chordomas with an indolent evolution from aggressive types leading rapidly to recurrence and death on which more aggressive treatments should be applied.

Developing a Web 2.0 telemedical education system: the AJAX-Cocoon portal.

Web 2.0 technologies such as wikis, podcasts/vodcasting, blogs and semantic portals could be quite effective tools in e-learning for health professionals. If effectively deployed, such tools can offer a way to enhance students', clinicians' and patients' learning experiences, and deepens levels of learners' engagement and collaboration within medical learning environments. However, Web 2.0 requires simplicity of use as well as integration with modern web technologies. This article presents a Web 2.0 telemedical portal, which provides a social community-learning paradigm from the desk of the physician, the student, the hospital administrator, or the insurer. The presented portal utilises RESTful web services and techniques like content syndication, mushups and Asynchronous JavaScript API and XML (AJAX). The designed portal is based on the Apache Cocoon RESTful framework for sharing Digital Imaging and Communications in Medicine (DICOM) medical case studies. Central to this article is the integration between Cocoon and AJAX. The proposed AJAX-Cocoon portal utilises a JSP portlet architecture, which manages the interaction dynamics and overcomes the shortcomings of the JSR 168 and WSRP 1.0 standards.

Double-door laminoplasty in managing multilevel myelopathy: technique description and literature review.

Cervical laminoplasty has become a popular technique for the treatment of cervical myelopathy resulting from multilevel canal stenosis. The goal of this technique is to increase the spinal canal space and to reconstruct the posterior bony arch at the same time. The most common reason for laminoplasty failure is restenosis because of hinge closure. In the present report, the authors describe a variation of the double-door laminoplasty using a specifically tailored plate. The present technique is a modification of the double-door laminoplasty by using a specifically developed plate (Senegas' Plate--by Stryker Technology, Kalamazoo, MI), which allows to fix the two hemilamina in an open and expanded position re-establishing also the posterior canal arch. This procedure was implemented in a series of 22 patients. The device has been successfully implanted in all patients. At a mean follow-up of 21.1 months all patients showed a remarkable neurological improvement documented by serial clinical and radiological investigations. The present study indicates that this specific device effectively preserves the postoperative sagittal cervical canal diameter and provides a rigid construct, and in addition, it is very easy and fast to apply minimizing the risk of iatrogenic injuries, blood loss, and operative time.

Spinal subdural hematoma.

The authors report a case of spinal subdural hematoma in a 51-year-old man who experienced a sudden onset of back pain accompanied by vomiting and headache without paralysis or paraparesis. CT Scan, myelography and MRI revealed a subdural hematoma at the levels of 6th, 7th and 8th thoracic vertebrales. Laminectomy allowed the removal of an encapsulated cyst formation filled with xanthochromic fluid and some blood clots. The follow-up was uneventful.

[Cerebrospinal fluid fistula--indications for treatment with lumbar puncture and drainage. Report of 66 cases]. / Die Liquorfistel--Indikationen zur Behandlung mit Lumbalpunktion und Drainage. Bericht über 66 Fälle.

The authors present a series of 66 cases of cerebrospinal fluid fistulas. Ways of localizing the fistula as well as different therapeutic methods are studied. They insist on the efficiency of external lumbar drainage of the cerebro-spinal fluid which permits a fair number of patients to recover without surgery.