A columnar mini phantom is designed as recommended by ESTRO to measure the Head Scatter Factor (S C ) for 6 MV beam of two linear accelerators. The measurement of S C at different orientations of the chamber, parallel and perpendicular at 1.5 cm depth predicts the deviation of 2.05% and 1.9% for Elekta and Siemens linear accelerators respectively. The measurement of S C at 1.5 cm is higher compared to 10 cm depth for both the linear accelerators suggesting the electron contamination at 1.5 cm depth. The effect of wedges on S C yields a significant contribution of 3.5% and 5% for Siemens and Elekta linear accelerators respectively. The collimator exchange effect reveals the opening of upper jaw increases the S C irrespective of the linear accelerator. The result emphasizes the need of S C measurement at 10 cm. The presence of wedge influences the S C value and the SSD has no influence on S C . The measured S C values are in good agreement with the published data.

Radiotherapy is an integral part of a well-defined cancer management program. Bangladesh is a fast-growing East Asian country with 161 million population, and approximately 2 lakh cancer patients are diagnosed newly ever year. Though there are several modern treatment facilities to deliver radiotherapy, only limited facilities were available to deliver stereotactic radiotherapy (SRS) programs for needy patients. Evercare Hospitals Dhaka has recently started SRS and stereotactic therapy (SRT) with a dedicated team of trained people. The hospital is equipped with modern linear accelerator capable of delivering high dose rate mode and micro multileaf collimators with 2.45-mm thickness at isocenter to deliver larger doses of radiation precisely. This paper summarizes patient selection criteria and workflow for the SRS/SRT treatment established, including patient preparation, image data acquisition, target and organ at risk delineation on CT (computed tomography) and MRI (magnetic resonance imaging) images, treatment planning process, and quality assurance. Each stage of the process is explained in detail, with specific emphasis on certain areas to achieve a higher degree of accuracy. This article also highlights the need for dedicated timeout procedures to be followed to avoid drastic errors in treatment delivery. We also summarized demographics data of patients treated in the first 6 months, including diagnosis, sizes of lesions, and dose fraction. The dosimetric and setup uncertainties encountered during SRS/SRT treatment delivery are also described. Though, initially, we faced challenges, SRS/SRT treatment was successfully implemented and more than 35 patients were treated, with appreciable clinical outcomes.

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Purpose: To present first case of refractory trigeminal Neuralgia treated with SRS in Bangladesh, procedural technique, and outcomes in terms of pain relief. Background: Trigeminal neuralgia (TN), classically known as tic doloureaux is a chronic and recurrent disabling pain syndrome, which described as episodes of lancinating pain over the face along the sensory distribution of trigeminal nerve. First line management of TN is medical with different permutation & combination to control the pain. After the failure of medical management, non-invasive SRS is an established modality to achieve long term pain control. Here, we are reporting a case of TN treated with LINAC based SRS. Case Presentation: A 61 years old, gentleman who developed piercing pain inside his left eye for a duration 1-1.5 sec, precipitated while shaving, brushing teeth in year 2015, occurred 4-5 time a day. He was diagnosed as left TN of V1, started on Carbamazepine, Pregabalin. In 3 years, pain progressed to involve all 3 branches. Even combination Carbamazepine, Gabapentin, Tramadol, Amitriptyline, Clonazepam, & Morphine could not control the pain. Pain was persisting all over the day and he also developed suicidal tendency. Later he has been referred to us for SRS. SRS was done in April-2019, a dose of 90Gy was delivered to the Distal Retrogasserian (RG) also called Marseille point of trigeminal nerve root. Eight months after the SRS patient is almost free of pain without any Medicine. Conclusions: LINAC based SRS is a non-invasive, frameless, and safe procedure with excellent pain control for refractory Trigeminal neuralgia. Bang. J Neurosurgery 2020; 10(1): 123-129

Stereotactic Radiosurgery has been widely utilized for the treatment of intracranial lesions, and this paper presents our experience in treating schwannomas in Bangladesh. This case series was described to present our institutional experience and procedural technique adapted for treating intracranial schwannomas using stereotactic Radiosurgery (SRS) by Linear accelerators. This case series since starting our radiosurgery program in March 2019, we have treated three patients of intracranial schwannoma. Two patients had vestibular schwannoma, and one had Trigeminal Schwannoma. All three patients first underwent surgical intervention and on recurrence/progression treated with stereotactic Radiosurgery. Tumor volume ranged from 4.47 to 10.22 cm3. The dose prescription ranges from 13 to 14Gy in one or two fractions, which was subject to tumor volume, its proximity to a critical structure, existing neurologic deficit, and optimal balance between prescribed dose and predicted complications. All three procedure was free of any immediate adverse event. LINAC based Stereotactic Radiosurgery was found to be a safe and effective option for the treatment of schwannomas. All three patients have a very good clinical outcome, and one patient who has more than one-year post-SRS revealed a significant regression in the size of the tumor. Journal of National Institute of Neurosciences Bangladesh, July 2021, Vol. 7, No. 2, pp. 181-189