Commissioning of a RayStation structure template for the iBEAM evo Couchtop.

Accurate radiotherapy treatment planning requires attenuation through the treatment couch to be accounted for in dose calculation. This is commonly performed by using contouring tools to add a virtual structure in the shape of the treatment couch and assigning the preferred absorption properties. The RayStation treatment planning system (TPS) allows users to assign a material that comprises both an elemental structure and a physical density.

Targeting of externalized αB-crystallin on irradiated endothelial cells with pro-thrombotic vascular targeting agents: Potential applications for brain arteriovenous malformations.

Background: Vascular targeting uses molecular markers on the surface of diseased vasculature for ligand-directed drug delivery to induce vessel occlusion or destruction. In the absence of discriminatory markers, such as in brain arteriovenous malformations (AVMs), stereotactic radiosurgery may be used to prime molecular changes on the endothelial surface. This study explored αB-crystallin (CRYAB) as a radiation induced target and pre-tested the specificity and efficacy of a CRYAB-targeting coaguligand for in vitro thrombus induction.

Occlusion of Animal Model Arteriovenous Malformations Using Vascular Targeting.

Brain arteriovenous malformations (AVMs) are a significant cause of intracerebral hemorrhage in children and young adults. Currently, one third of patients have no viable treatment options. Vascular targeting agents (VTAs) are being designed to deliver pro-thrombotic molecules to the abnormal AVM vessels for rapid occlusion and cure.

Radiation-Stimulated Translocation of CD166 and CRYAB to the Endothelial Surface Provides Potential Vascular Targets on Irradiated Brain Arteriovenous Malformations.

Vascular targeting with pro-thrombotic antibody-conjugates is a promising biological treatment for brain arteriovenous malformations (bAVMs). However, targeted drug delivery relies on the identification of unique or overexpressed markers on the surface of a target cell. In the absence of inherent biological markers, stereotactic radiosurgery may be used to prime induction of site-specific and targetable molecular changes on the endothelial surface.

Volume not number of metastases: Gamma Knife radiosurgery management of intracranial lesions from an Australian perspective.

Background And Purpose: To assess the response of the first cohort of patients treated with Gamma Knife radiosurgery in Australia.

Materials And Methods: A prospectively collected cohort of 180 patients with intracranial metastases from different primaries was treated between August 2010 and July 2017. Survival was calculated using the Kaplan-Meier's method.

The Elekta Fraxion™ system is not suitable for maxillary fixation in canine conformal radiation therapy techniques.

In this prospective, exploratory study, we evaluated the positioning accuracy in a group of 15 dogs undergoing fractionated stereotactic radiotherapy for tumors affecting the head, using a modified human maxillary fixation device (Elekta Fraxion™ system). Positioning was assessed using on-board volumetric imaging, with a six-degrees-of-freedom image registration technique. Prior to treatment delivery, CBCT images were obtained and patient alignment was corrected, in both translational and rotational planes, using a six-degrees-of-freedom robotic patient positioning system (HexaPOD Evo RT System).

Effects of FOXM1 inhibition and ionizing radiation on melanoma cells.

Metastatic melanoma can be highly refractory to conventional radiotherapy and chemotherapy but combinatorial-targeted therapeutics are showing greater promise on improving treatment efficacy. Previous studies have shown that knockdown of Forkhead box M1 () can sensitize various tumor types to radiation-induced cell death. The effect of combining radiation with a small molecule FOXM1 inhibitor, Siomycin A, on growth, death and migration of a metastatic melanoma cell line (SK-MEL-28) that overexpresses this pleiotropic cell cycle regulator was investigated.

Ionizing radiation reduces ADAM10 expression in brain microvascular endothelial cells undergoing stress-induced senescence.

Cellular senescence is associated with aging and is considered a potential contributor to age-associated neurodegenerative disease. Exposure to ionizing radiation increases the risk of developing premature neurovascular degeneration and dementia but also induces premature senescence. As cells of the cerebrovascular endothelium are particularly susceptible to radiation and play an important role in brain homeostasis, we investigated radiation-induced senescence in brain microvascular endothelial cells (EC).

Radiosurgery Alters the Endothelial Surface Proteome: Externalized Intracellular Molecules as Potential Vascular Targets in Irradiated Brain Arteriovenous Malformations.

Stereotactic radiosurgery (SRS) is an established treatment for brain arteriovenous malformations (AVMs) that drives blood vessel closure through cellular proliferation, thrombosis and fibrosis, but is limited by a delay to occlusion of 2-3 years and a maximum treatable size of 3 cm. In this current study we used SRS as a priming tool to elicit novel protein expression on the endothelium of irradiated AVM vessels, and these proteins were then targeted with prothrombotic conjugates to induce rapid thrombosis and vessel closure. SRS-induced protein changes on the endothelium in an animal model of AVM were examined using in vivo biotin labeling of surface-accessible proteins and comparative proteomics.

Evaluation of accuracy and reproducibility of a relocatable maxillary fixation system for fractionated intracranial stereotactic radiation therapy.

Introduction: Accurate localisation is an essential component for the delivery of intracranial stereotactic treatment. For fractionated stereotactic radiotherapy, we compared the daily localisation accuracy of a standard thermoplastic mask with a new maxillary fixation device (MFD).

Methods: Daily pre-treatment kV cone-beam computed tomography (CBCT) scans of 23 patients (12 localised in the MFD and 11 in the mask) with benign skull-based lesions were reviewed retrospectively.

Use of a megavoltage electronic portal imaging device to identify prosthetic materials.

To achieve accurate dose calculations in radiation therapy the electron density of patient tissues must be known. This information is ordinarily gained from a computed tomography (CT) image that has been calibrated to allow relative electron density (RED) to be determined from CT number. When high density objects such as metallic prostheses are involved, direct use of the CT data can become problematic due to the artefacts introduced by high attenuation of the beam.

The dependence of computed tomography number to relative electron density conversion on phantom geometry and its impact on planned dose.

A computed tomography number to relative electron density (CT-RED) calibration is performed when commissioning a radiotherapy CT scanner by imaging a calibration phantom with inserts of specified RED and recording the CT number displayed. In this work, CT-RED calibrations were generated using several commercially available phantoms to observe the effect of phantom geometry on conversion to electron density and, ultimately, the dose calculation in a treatment planning system. Using an anthropomorphic phantom as a gold standard, the CT number of a material was found to depend strongly on the amount and type of scattering material surrounding the volume of interest, with the largest variation observed for the highest density material tested, cortical bone.