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More often the embolic materials in the brain create artefacts in the planning CT images that could lead to a dose variation in planned and delivered dose. The aim of the study was to evaluate the dosimetric effect of artefacts generated by the Onyx™ embolization material during Stereotactic Radiosurgery/Radiotherapy (SRS/SRT) planning. An in-house made novel Polymethyl Methacrylate (PMMA) head phantom (specially designed for SRS/SRT plans) was used for this purpose. For the evaluation process, we have created concentric ring structures around the central Onyx materials on both the CT sets (with and without Onyx material). The verification plans were generated using different algorithms namely Analytical Anisotropic Algorithm (AAA), Acuros XB and Monaco based Monte Carlo on both CT sets. Mean integral dose over the region of interest were calculated in both CT sets. The dosimetric results shows, due to the presence of Onyx material, relative variation in mean integral dose to the proximal structure (Ring 1) were −4.02%, −2.98%, and −2.49% for Monte Carlo, Acuros XB, and AAA respectively. Observed variations are attributed to the presence of artefacts due to Onyx material. Artefacts influence the accuracy of dose calculation during the planning. All the calculation algorithms are not equally capable to account such variations. Special cares are to be taken while choosing the calculation algorithms as it impacts the results of treatment outcome.

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Background:Indian-Asian multiple sclerosis behaves somewhat differently from Western disease. It is not known if the response to β-interferon is also different.Aim:To demonstrate the decrease in relapses with β-interferon in Indian patients with multiple sclerosis.Patients and Methods:Patients with relapsing–remitting or secondary progressive multiple sclerosis with at least two relapses were started on β-interferon.Results:Sixteen patients were followed up for a period of 1–3 years. Fifteen had relapsing–remitting multiple sclerosis (MS). The mean number of relapses in these patients before interferons were started was 3.4. The mean yearly relapse rate was 1.3. The mean Kurtzke Expanded Disability Status Scale (EDSS) at the start of β-interferon therapy in relapsing–remitting MS was 1.7. Ten of these patients were on Avonex® (interferon β1a) and six (including the patient with secondary progressive MS) were on Betaferon® (interferon β1b). On follow-up, three patients (two on Avonex® and one on Betaferon® ) had relapses. The respective β-interferon being received by these patients was continued, with no further relapses. The remaining patients had no relapse or clinical or MRI progression after starting the drug. The side effect profile of the drug in these patients was favorable; although nearly all developed fever on the first day of the injection, only 50% of the patients continued to have fever after 3 months. Two patients developed psychiatric symptoms, requiring discontinuation of the drug.Conclusion:Our prospective follow-up study shows that β-interferons are safe and effective in Indian patients with relapsing–remitting or secondary progressive MS.