Genetic alterations of TP53 and OTX2 indicate increased risk of relapse in WNT medulloblastomas.

This study aimed to re-evaluate the prognostic impact of TP53 mutations and to identify specific chromosomal aberrations as possible prognostic markers in WNT-activated medulloblastoma (WNT-MB). In a cohort of 191 patients with WNT-MBs, mutations in CTNNB1, APC, and TP53 were analyzed by DNA sequencing. Chromosomal copy-number aberrations were assessed by molecular inversion probe technology (MIP), SNP6, or 850k methylation array hybridization.

Medulloblastoma in Adults: Cytogenetic Phenotypes Identify Prognostic Subgroups.

Adult medulloblastomas (MB) are rare. We investigated the genetic landscape and prognostic impact of genetic aberrations in a cohort of 117 adult medulloblastomas. Histological features and pathway activation were evaluated at the protein level; 14.

Study of out-of-field dose in photon radiotherapy: A commercial treatment planning system versus measurements and Monte Carlo simulations.

Purpose: An accurate assessment of out-of-field dose is necessary to estimate the risk of second cancer after radiotherapy and the damage to the organs at risk surrounding the planning target volume. Although treatment planning systems (TPSs) calculate dose distributions outside the treatment field, little is known about the accuracy of these calculations. The aim of this work is to thoroughly compare the out-of-field dose distributions given by two algorithms implemented in the Monaco TPS, with measurements and full Monte Carlo simulations.

Technical Note: An hybrid parallel implementation for EGSnrc Monte Carlo user codes.

Purpose: The purpose of this study was to present a parallel solution for the EGSnrc Monte Carlo code system combining MPI and OpenMP programming models as an alternative to the provided implementation, based on the use of a batch-queueing system (BQS).

Methods: Relying on a previous implementation based on OpenMP by E. Doerner and P.

Technical Note: Parallel implementation of the EGSnrc Monte Carlo simulation of ionizing radiation transport using OpenMP.

Purpose: To present the implementation of a new option for parallel processing of the EGSnrc Monte Carlo system using the OpenMP API, as an alternative to the provided method based on the use of a batch queuing system (BQS).

Methods: The parallel solution presented, called OMP_EGS, makes use of OpenMP features to control the workload distribution between the compute units. These features were inserted into the original EGSnrc source code through properly defined macros.

Implementation of a double Gaussian source model for the BEAMnrc Monte Carlo code and its influence on small fields dose distributions.

The shape of the radiation source of a linac has a direct impact on the delivered dose distributions, especially in the case of small radiation fields. Traditionally, a single Gaussian source model is used to describe the electron beam hitting the target, although different studies have shown that the shape of the electron source can be better described by a mixed distribution consisting of two Gaussian components. Therefore, this study presents the implementation of a double Gaussian source model into the BEAMnrc Monte Carlo code.

Genetic Analysis of Diffuse High-Grade Astrocytomas in Infancy Defines a Novel Molecular Entity.

Pediatric high-grade gliomas are considered to be different when compared to adult high-grade gliomas in their pathogenesis and biological behavior. Recently, common genetic alterations, including mutations in the H3F3A/ATRX/DAXX pathway, have been described in approximately 30% of the pediatric cases. However, only few cases of infant high-grade gliomas have been analyzed so far.

Development and application of a dose verification tool using a small field model for TomoTherapy.

Helical TomoTherapy® is a radiation delivery technique that uses the superposition of many small fields to precisely deliver the prescribed dose to the patient. This work presents a dose verification tool that can be used as part of a quality assurance program for a tomotherapy system. This tool is based on a small field model that takes into account the two main effects that influence the dose distribution in small fields: the extended shape of the radiation source and the loss of lateral charged particle equilibrium (CPE) within the field.

Development and validation of a BEAMnrc component module for a miniature multileaf collimator.

A new component module (CM) named mini multileaf collimator (mMLC) was developed for the Monte Carlo code BEAMnrc. It models the geometry of the add-on miniature multileaf collimator ModuLeaf (MRC Systems GmbH, Heidelberg, Germany, now part of Siemens, Erlangen, Germany). The new CM is partly based on the existing CM called DYNVMLC.