Monitor unit verification for Varian TrueBeam VMAT plans using Monte Carlo calculations and phase space data.

To use the open-source Monte Carlo (MC) software calculations for TPS monitor unit verification of VMAT plans, delivered with the Varian TrueBeam linear accelerator, and compare the results with a commercial software product, following the guidelines set in AAPM Task Group 219. The TrueBeam is modeled in EGSnrc using the Varian-provided phase-space files. Thirteen VMAT TrueBeam treatment plans representing various anatomical regions were evaluated, comprising 37 treatment arcs.

Blinding of Residency Applications in Medical Physics: Promises and Pitfalls.

Purpose: The feasibility of blinding applications for a medical physics residency program has yet to be demonstrated in the literature. We explore the application of an automated approach with human review and intervention to blind applications during the annual medical physics residency review cycle.

Methods And Materials: Applications were blinded using an automated process and used for the first phase of residency review in the program.

Hypertensive emergency and seizures in a 30-year-old man with anti-glomerular basement membrane disease.

Anti-glomerular basement membrane disease can rapidly lead to renal failure and blood pressure dysregulation. A rare complication is hypertensive encephalopathy in the form of seizures. Patients who have a negative initial seizure workup should have an MRI.

A Hamiltonian Engine for Radiotherapy Optimization.

We apply a new hardware and software platform called the Hamiltonian Engine for Radiotherapy Optimization (HERO) to the problem of Intensity-Modulated Radiation Therapy (IMRT) treatment planning. HERO solves large general-form binary optimization problems by decomposing them into sub-problems and approximating them using a quadratic pseudo-boolean function. Optimizing the resulting function becomes a quadratic unconstrained binary optimization (QUBO) problem, which has been widely studied and has numerous applications in various fields.

Enhanced optimization of volumetric modulated arc therapy plans using Monte Carlo generated beamlets.

Purpose: A treatment planning system (TPS) produces volumetric modulated arc therapy (VMAT) plans by applying an optimization process to an objective function, followed by an accurate calculation of the final, deliverable dose. However, during the optimization step, a rapid dose calculation algorithm is required, which reduces its accuracy and its representation of the objective function space. Monte Carlo (MC) routines, considered the gold standard in accuracy, are currently too slow for practical comprehensive VMAT optimization.

Secondary monitor unit calculations for VMAT using parallelized Monte Carlo simulations.

We have developed a fast and accurate in-house Monte Carlo (MC) secondary monitor unit (MU) check method, based on the EGSnrc system, for independent verification of volumetric modulated arc therapy (VMAT) treatment planning system dose calculations, in accordance with TG-114 recommendations. For a VMAT treatment plan created for a Varian Trilogy linac, DICOM information was exported from Eclipse. An open-source platform was used to generate input files for dose calculations using the EGSnrc framework.

A juvenile subfossil crocodylian from Anjohibe Cave, Northwestern Madagascar.

Madagascar's subfossil record preserves a diverse community of animals including elephant birds, pygmy hippopotamus, giant lemurs, turtles, crocodiles, bats, rodents, and carnivorans. These fossil accumulations give us a window into the island's past from 80,000 years ago to a mere few hundred years ago, recording the extinction of some groups and the persistence of others. The crocodylian subfossil record is limited to two taxa, Voay robustus and Crocodylus niloticus, found at sites distributed throughout the island.