All of the following are indications for Gamma Knife Radiosurgery EXCEPT
Correct Answer: Brain tumours or lesions 4 cm or larger in diameter
Description: (D) Brain tumors or lesions 4 cm or larger in diameter# GAMMA KNIFE RADIOSURGERY or Stereotactic Radiosurgery (SRS), is a very precise form of therapeutic radiology. Even though it is called surgery, a Gamma Knife procedure does not involve actual surgery, nor is the Gamma Knife really a knife at all. It uses beams of highly-focused gamma rays to treat small to medium size lesions, usually in the brain. Many beams of gamma radiation join to focus on the lesion under treatment, providing a very intense dose of radiation without a surgical incision or opening.> Gamma Knife radiosurgery has shown some promise for treating conditions such as tremor and rigidity related to Parkinson's disease, epilepsy, and chronic pain.# Gamma Knife Radiosurgery Indications:1. Arteriovenous malformation (AVM) can be managed by microsurgery, endovascular embolization, or SRS.2. Trigeminal neuralgia (TN): Treatment options include medications, surgical procedures including microvascular decompression, radiofrequency rhizotomy, glycerol rhizolysis and balloon compression, and SRS (Gamma Knife- or linear accelerator-basedradiosurgery). SRS targets the proximal trigeminal root3. Meningioma: SRS can deliver a single, high dose of radiation to a localized area in the brain for the treatment of meningiomas that are unresectable, recurrent, or residual after surgery.4. Acoustic neuroma or acoustic schwannoma, acoustic neurinoma, vestibular schwannoma, and vestibular neurilemoma: It is a Schwann cell-derived tumor arising from the vestibular portion of the eighth cranial nerve. Treatment options include observation, microsurgery, SRS, and stereotactic radiotherapy.5. Pituitary adenoma.Treatment options include microresection, medical therapy, fractionated radiotherapy, SRS, and stereotactic radiotherapy. SRS has been used in the treatment of endocrine-inactive as well as secretory pituitary adenomas.6. Brain metastases: Brain metastases tend to be spherical and have a sharp demarcation from normal brain parenchyma. These characteristics are ideal for SRS because spherical dose distributions can readily be generated by the radio surgical systems and the use of tight margins is feasible.7. Malignant glioma is highly lethal. Multiple strategies, including SRS, have been used to execute dose escalation8. Glomus tumors are ideal targets for SRS since they are well demarcated and are readily identified on MRI.9. Low-grade astrocytoma: The standard treatment for low-grade astrocytoma is surgery and/or conventional radiotherapy. SRS has been used to treat low-grade astrocytoma in the recurrent, boost, and primary setting10. Ependymoma: The standard treatment for intracranial ependymoma is maximal safe resection followed by postoperative radiotherapy.11. Uveal melanoma: Historically, uveal melanomas were primarily managed by enucleation. Eye plaques (using iodine-125) and proton beam therapy have since been established as treatment alternatives for the disease. Use of Gamma Knife-based SRS has been explored in uveal melanoma.12. Epilepsy: SRS has been used to manage seizure disorders such as mesial temporal epilepsy (MTE) and seizures caused by AVMs, cavernomas, and hypothalamic hamartomas.> GAMMA KNIFE Radiosurgery Contraindications:1. Gamma Knife-based SRS is not suitable for tumors or lesions 4 cm or larger in diameter or immediately adjacent to eloquent structures such as the optic apparatus and brainstem if a dose of higher than 12 Gy is needed to control the tumor.2. In the pediatric age group, Gamma Knife-based SRS is, in general, not suitable for patients whose skulls are not completely fused, because invasive pin placement for securing the stereotactic head frame is required in Gamma Knife surgery.3. In circumstances in which the tumor is located inferior to the skull base to a degree that the stereotactic head frame cannot be placed to enable adequate stereotactic localization, a frameless system such as Cyber Knife can be used.
Category:
Radiology
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