Summary Understanding the spectrum of neurological manifestations of COVID-19 and the impact of COVID-19 on patients with underlying neurological conditions might help to improve outcomes.Background Recent studies have reported observing antioxidant, anti-inflammatory, and anti-aging properties of α-L-Guluronic acid (G2013) in animal and human studies. It has been theorized that the antioxidant and anti-inflammatory properties of G2013 might be beneficial in epilepsy treatment. Objective We sought to determine G2013's effects on epileptic activity in a kindling-induced animal model. Methods Thirty rats were randomly divided evenly into three groups (10 rats in each group) 1) the G2013 group, which was treated with daily injections of G2013 for five days prior to the start of the study; during the 14-day study period, the G2013 rats were given single, daily injections of G2013 that preceded single daily injections of pentylenetetrazole (PTZ), a compound used to induce seizures; 2) the Normal group, which only received injections of saline during the 14-day study, with no seizure induction; and 3) the Control group, which received PTZ injections alone (for seizure induction) for the 14-day studyceived PTZ alone, suggesting that G2013's epileptogenic property overshadows its anti-inflammatory effects when applied to a kindled animal model of study.Idiopathic glossopharyngeal neuralgia (GPN) is a rare disorder of the ninth cranial nerve characterized by severe paroxysmal pain affecting the ear, tongue and throat. Frame-based radiosurgery (SRS) has been shown to be an effective option. We report the first successful pain alleviation by frameless SRS in a GPN patient that failed both medical and surgical interventions.We present the case of radiation myonecrosis of the iliopsoas muscle, identified five months after stereotactic body radiation therapy (SBRT, 21 Gy in three fractions) to a metastatic lesion in the right iliac bone of a patient with leiomyosarcoma. The patient had been treated with various chemotherapeutic agents, most notably docetaxel and gemcitabine for five cycles 10 months prior to SBRT. As skeletal muscle is a radio-resistant organ, myonecrosis is rare, but previous case reports suggest that the administration of gemcitabine may increase the likelihood of radiation toxicity, including radiation myonecrosis. Physicians may consider conventional fractionation, rather than a hypofractionated course, in patients who have received or will receive gemcitabine.Purpose A major factor in dose-fractionation selection for intracranial metastases in stereotactic radiosurgery (SRS) is the size of the target lesion and consequently the dose-volume to the surrounding normal brain tissue (NTV), as this has been correlated with brain radiation necrosis (RN). This study outlines the development and validation of a predictive model that can estimate the NTV for a range of dose-fractionation schemes based on target diameter from a patient's MRI. Methods Data from a cohort of historical SRS clinical treatment plans were used to extract three key input parameters for the model - conformity index, gradient index, and a scaling factor which were then defined as a function of target volume. The relationship between the measured tumour diameter and the NTV was established by approximating the target to a spherical volume covered by the prescription dose. A scaling factor (λNTV) describes the non-linear fall-off of dose beyond the target. This was then used to provide a first-order approximation of the resulting NTV. The predictive model was retrospectively validated using linear regression against actual NTV values from 39 historical SRS plans which were independent to the derivation process. read more The model was validated for both three-dimensional (3D) target diameter and axial-only two-dimensional (2D) estimates of target diameter values. Results The prediction model directly relates lesion diameter to NTV volume (cc) and thus RN risk for a given dose-fractionation. The predicted NTV (cc) for both 3D- and 2D-based volume estimates could statistically significantly predict the actual NTV (cc) R2=0.942 (p less then .0005) for 3D-based estimate, and R2=0.911 (p= less then .0005) for axial-only 2D-based estimate. Conclusion This knowledge-based method for NTV prediction in intracranial SRS provides the clinician with a decision support tool to appropriately select dose-fractionation prior to treatment planning.Early stage lung cancer is increasingly being treated using stereotactic body radiation therapy (SBRT). Several advanced treatment planning algorithms are now available in various commercial treatment planning systems. This work compares the dose distributions calculated for the same treatment plan using, five algorithms, in three different treatment planning systems. All plans were normalized to ensure the prescription dose covers 95% of the planning target volume (PTV). Dose to the planning target volume (PTV) was compared using near-minimum dose (D98%), near-maximum dose (D2%) and dose homogeneity, while dose fall-off was compared using D2cm and R50. Dose to the lung was compared using V5Gy, V20Gy and mean lung dose. Statistical analysis shows that dose distributions calculated using Eclipse's Acuros XB and RayStation's Monte Carlo were significantly different from the other dose distributions for the PTV dose parameters investigated. For lung dosimetric parameters, this difference persisted for volumetric modulated arc therapy (VMAT) plans but not for conformal arc plans. While normal tissue complication probability (NTCP) differences were significant for some of the algorithms for VMAT delivery approaches, they were not significantly different for any algorithm for conformal arc plans. All parameters investigated here were within 5% between all algorithms. The results show that, while some small dosimetric differences can be expected around the PTV, the dose distribution to the rest of the treatment area, especially the lungs, should not be clinically-relevant when switching between one of the five algorithms investigated.The Gamma Knife® Icon™ CBCT facilitates frameless radiosurgery. In the vendor-recommended workflow, MRI is co-registered directly to CBCT for planning. Alternatively, MRI is co-registered to a diagnostic CT, which is then co-registered to CBCT. Our objective is to evaluate if this additional CT is necessary for more accurate registrations. Nine small spherical targets were generated onto 14 patient data-sets. Single-shot treatment plans were created. Geometric and dosimetric differences between the two workflows were determined. Mean target displacement was 0.5±0.3mm; average PTV coverage loss was 4.3±5.0%. For 19 clinical targets in 14 patients, the mean displacement and coverage change was 0.6±0.4mm and 1.3±1.6%. Eleven surrogate landmarks were contoured on a phantom MRI and registered to the CBCT using both workflows. The registration uncertainty was 0.50±0.65mm and 0.32±0.47mm for the MRI-CT-CBCT and MRI-CBCT respectively. As neither workflow was significantly more accurate, the additional CT is unnecessary for most cases.