Radiation brain surgery and fractioned stereotactic radiotherapy.
Introduction In general, oncologists have three weapons to fight against cancer: surgery, drugs chemotherapy, immunotherapyand radiation therapy. We have the same possibilities for the treatment of prostate volume normal radiopaedia tumours, but because of certain specialties of the prostate volume normal radiopaedia nervous system, the above-mentioned armamentarium is modified: The brain is locked into a rigid cave, thus growing of even benign tumours can cause life-threatening conditions because of the space occupation.
The damage of major portions of the brain is not compatible with life, or it results in significant deterioration of the quality of life. As a result of the blood-brain barrier system, the majority of classical chemotherapeutic drugs will not reach the cancer cells in a proper concentration.
On the other hand in some cases, chemotherapeutic agents are administered in the CSF to fight against cancer spreading via the CSF pathways.
Due to the fact that the majority of CNS cells do not divide, radiation therapy using the difference in sensitivity of normal and Tiberális a prosztatitisből cells against radiation can effectively be applied for the treatment of intracranial targets. Consequently, radiation therapy has become the most important and the most widely used tool in place of inoperable tumour or beside residual tumour or cavity surgery for a local control.
Furthermore, the radiosensitivity of different brain areas is considerably different: e. The rigidity of the scull, and the minor dislocation of the brain in the cranium make it possible to modify classical radiotherapy techniques when treating intracranial targets: Brain can be fixed through the scull with a precision of tenth of a millimeter… Thus we consider a little brain tissue dislocation the security margins of general radiation therapy and consequently the prostate volume normal radiopaedia of radiation load to normal tissue can be lowered.
In this chapter radiation therapy radiosurgery and fractionated stereotactic radiation therapy of the CNS mainly for intracranial targets is discussed.
First of all, the bases of fractionated radiation therapy are shown, then radiosurgery, fractionated stereotactic radiation therapy and the target diseases are discussed. Basic concepts 2.
Theoretically to determine the exact position of an object we need: A reference coordinate system A map, if the interrelation of the object is considered Prosztata adenoma táplálkozás the map has its own coordinate system, this one and the real coordinate system needs to be correlated to each other.
This procedure is the registration. In practice, there are frame based and frameless techniques. In the former case the stereotactic frame is the base of a 3D coordinate system. In case of frameless navigation the part of the body to be treated is immobilized in some way, and its position is compared to a reference system e. In both cases the CT, or MR picture data serve as reference maps for the navigation. The history of stereotaxy and surgical navigation The pioneers of intracranial neurosurgeons at the end of the 19th and the beginning of 20th centuries relied purely on their anatomical knowledge and clinical observations regarding the place, size and characteristics of certain brain structures and pathologies, since intracranial imaging was not yet available.
For the first time, a Russian professor, Zernov Dmitri Zernov,an anatomist in Moscow created and used a localization instrument encephalometer for anatomical studies and neurosurgical interventions. Prostate volume normal radiopaedia the help of this instrument he was able to determine the position of brain structures in polar coordinates.
He used the encephalometer to determine the position of the central sulcus, and revealing this place, he discovered a cerebral abscess. Figure 7. Figure 1. Kandel: Functional and stereotactic neurosurgery, Although clearly from above, he was the one who developed stereotaxy, his work was not known by the rest of the world, thus usually Sir Victor Horsley and his colleague Robert H.
Clarke are considered to build a stereotactic instrument first time in the world in for electrophysiological experiments in animals. Unfortunately they could not define the exact position of subcortical structures compared to bones in a humans, that is why this method did not spread for a long time.
During the next years and decades, procedures utilizing this technique developed rapidly but the transfer of image information to the given patient depended purely on the anatomical knowledge and power of spatial conception of the surgeon. The goal was to guide an instrument to a formerly defined point of the brain.
Home Epipharynx tumor The localisation of this tumor in the epipharynx is a rarity and unknown in the literature. Hátránya, hogy intubációkor zavarhatja a vizualizációt. A gastralis táplálás javasolt, ha a gyomorürülés biztosított, és nincs aspirációs veszély. The hypopharynx or laryngopharynx forms the most inferior portion of the pharynx, being the continuation of the oropharynx superiorly and both the larynx and esophagus inferiorly.
Frame based stereotaxy After all these, the stereotactic frames firmly attached to the scull spread widely. Initially, they have been used to guide discreet lesions in order to relive the symptoms of movement disorders, chronic pain, and epilepsy; and later to aspirate cysts, abscesses, to implant radio-isotopes, to make biopsies or for radiosurgery.
Epipharynx tumor - in presenting this study
The advantage of a stereotactic frame is its precise and reliable attachment and coordinate system. Its disadvantages in general neurosurgery : the frame is applied on the day of the surgery scala posterior structures can not be reached easily the frame may impede the surgeon the localization is feasible for single or a small number of targets it is hard to change target during surgery 2.
Frameless stereotaxy Recently called neuronavigation As a consequence of the exploding evolution of computation and imaging techniques DSA, CT, MR the possibility and quality of surgical planning also improved. On the other hand, the rich information collected prior to surgery should be transferred in some way to the operation field in order to use it during surgery.
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This task, requiring serious experience and orientation skills, was solved purely in mind of a traditional neurosurgeon. David Roberts developed a navigation system based on ultrasonography in This did not spread wide in clinical practice. InEiju Watanabe constructed a localization system that consisted of many joints and arms of given length.
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This instrument went into standardized production. At the early nineties, two further navigation systems emerged: the electromagnetic, and the optical.
The advantage of the electromagnetic system was that there was no need for direct optical contact between the machine and the surgical field, on the other hand the initial imprecision of 2 millimeters increased in vicinity of metals, which was its disadvantage. Thus optical systems spread wide their functioning is similar to GPS.