Isodoses-a set theory-based patient-specific QA measure to compare planned and delivered isodose distributions in photon radiotherapy.

Background: The gamma index and dose-volume histogram (DVH)-based patient-specific quality assurance (QA) measures commonly applied in radiotherapy planning are unable to simultaneously deliver detailed locations and magnitudes of discrepancy between isodoses of planned and delivered dose distributions. By exploiting statistical classification performance measures such as sensitivity or specificity, compliance between a planned and delivered isodose may be evaluated locally, both for organs-at-risk (OAR) and the planning target volume (PTV), at any specified isodose level. Thus, a patient-specific QA tool may be developed to supplement those presently available in clinical radiotherapy.

Are gamma passing rate and dose-volume histogram QA metrics correlated?

Purpose: The quality of a measured distribution of dose delivered against its corresponding radiotherapy plan is routinely assessed by gamma index (GI) and dose-volume histogram (DVH) metrics. Any correlation between error detection rates, as based on either of these approaches, while argued, has never been convincingly demonstrated. The dependence of the strength of correlation between the GI passing rate ( ) and DVH quality assurance (QA) metrics on various elements of the therapy plan has not been systematically investigated.

DeepBeam: a machine learning framework for tuning the primary electron beam of the PRIMO Monte Carlo software.

Background: Any Monte Carlo simulation of dose delivery using medical accelerator-generated megavolt photon beams begins by simulating electrons of the primary electron beam interacting with a target. Because the electron beam characteristics of any single accelerator are unique and generally unknown, an appropriate model of an electron beam must be assumed before MC simulations can be run. The purpose of the present study is to develop a flexible framework with suitable regression models for estimating parameters of the model of primary electron beam in simulators of medical linear accelerators using real reference dose profiles measured in a water phantom.

Analysis of Indoor Radon Data Using Bayesian, Random Binning, and Maximum Entropy Methods.

Three statistical methods: Bayesian, randomized data binning and Maximum Entropy Method (MEM) are described and applied in the analysis of US radon data taken from the US registry. Two confounding factors-elevation of inhabited dwellings, and UVB (ultra-violet B) radiation exposure-were considered to be most correlated with the frequency of lung cancer occurrence. MEM was found to be particularly useful in extracting meaningful results from epidemiology data containing such confounding factors.

National Professional Development Center on Autism Spectrum Disorders (NPDC) model - an integrated model of evidence-based practices for autism spectrum disorder.

Autism spectrum disorder (ASD) as a serious neurodevelopmental condition requires intensive and comprehensive interventions, particularly interventions found to be effective through rigorous research. The National Professional Development Center on Autism Spectrum Disorders (NPDC) was formed in the USAin order to conduct a comprehensive review of ASD-related evidence-based practices (EBPs) and to create amodelof implementing such practices for children, adolescents and young adults (from preschool to high school education level). The NPDC final review, being the most comprehensive to date (the initial search included 29,105 articles) identified 27 ASD-focused EBPs.

THE ROLE OF PARTICLE SPECTRA IN MODELING THE RELATIVE BIOLOGICAL EFFECTIVENESS OF PROTON RADIOTHERAPY BEAMS.

Radiotherapy beams of protons or heavier ions generate secondary particles through nuclear interactions over different patient tissues. The resulting particle spectra depend on the tissue composition and on charge and energy of the primary beam ions. In proton radiotherapy, predictive radiobiological models usually apply dose-averaged linear energy transfer (LET).

Ion recombination and polarity correction factors for a plane-parallel ionization chamber in a proton scanning beam.

Purpose: To evaluate the effect on charge collection in the ionization chamber (IC) in proton pencil beam scanning (PBS), where the local dose rate may exceed the dose rates encountered in conventional MV therapy by up to three orders of magnitude.

Methods: We measured values of the ion recombination (k ) and polarity (k ) correction factors in water, for a plane-parallel Markus TM23343 IC, using the cyclotron-based Proteus-235 therapy system with an active proton PBS of energies 30-230 MeV. Values of k were determined from extrapolation of the saturation curve and the Two-Voltage Method (TVM), for planar fields.

Measurement of stray neutron doses inside the treatment room from a proton pencil beam scanning system.

Purpose: To measure the environmental doses from stray neutrons in the vicinity of a solid slab phantom as a function of beam energy, field size and modulation width, using the proton pencil beam scanning (PBS) technique.

Method: Measurements were carried out using two extended range WENDI-II rem-counters and three tissue equivalent proportional counters. Detectors were suitably placed at different distances around the RW3 slab phantom.

Proton microbeam radiotherapy with scanned pencil-beams--Monte Carlo simulations.

Irradiation, delivered by a synchrotron facility, using a set of highly collimated, narrow and parallel photon beams spaced by 1 mm or less, has been termed Microbeam Radiation Therapy (MRT). The tolerance of healthy tissue after MRT was found to be better than after standard broad X-ray beams, together with a more pronounced response of malignant tissue. The microbeam spacing and transverse peak-to-valley dose ratio (PVDR) are considered to be relevant biological MRT parameters.

A numerical method to optimise the spatial dose distribution in carbon ion radiotherapy planning.

The authors describe a numerical algorithm to optimise the entrance spectra of a composition of pristine carbon ion beams which delivers a pre-assumed dose-depth profile over a given depth range within the spread-out Bragg peak. The physical beam transport model is based on tabularised data generated using the SHIELD-HIT10A Monte-Carlo code. Depth-dose profile optimisation is achieved by minimising the deviation from the pre-assumed profile evaluated on a regular grid of points over a given depth range.

A TPS kernel for calculating survival vs. depth: distributions in a carbon radiotherapy beam, based on Katz's cellular Track Structure Theory.

An algorithm was developed of a treatment planning system (TPS) kernel for carbon radiotherapy in which Katz's Track Structure Theory of cellular survival (TST) is applied as its radiobiology component. The physical beam model is based on available tabularised data, prepared by Monte Carlo simulations of a set of pristine carbon beams of different input energies. An optimisation tool developed for this purpose is used to find the composition of pristine carbon beams of input energies and fluences which delivers a pre-selected depth-dose distribution profile over the spread-out Bragg peak (SOBP) region.

The principles of Katz's cellular track structure radiobiological model.

The cellular track structure theory (TST), introduced by Katz in 1968, applies the concept of action cross section as the probability of targets in the radiation detector being activated to elicit the observed endpoint (e.g. cell killing).

Does microwave interstitial hyperthermia prior to high-dose-rate brachytherapy change prostate volume or therapy plan parameters?

Purpose: In this prospective preliminary study we evaluated changes of prostate volume and changes of brachytherapy treatment plan parameters due to interstitial hyperthermia (IHT) applied prior to high-dose-rate brachytherapy (HDRBT), compared to our standard HDRBT procedure.

Material And Methods: In a group of 60 consecutive patients with prostate adenocarcinoma, 30 were treated with HDRBT alone and 30 with IHT preceding HDRBT. Prior to catheter implantation, a 'virtual' treatment plan (VP) was complied, a 'live' plan (LP) was prepared before patient irradiation, and a 'post' plan (PP) was drawn up after completing the irradiation procedure.

Performance of two commercial electron beam algorithms over regions close to the lung-mediastinum interface, against Monte Carlo simulation and point dosimetry in virtual and anthropomorphic phantoms.

Electron radiotherapy is applied to treat the chest wall close to the mediastinum. The performance of the GGPB and eMC algorithms implemented in the Varian Eclipse treatment planning system (TPS) was studied in this region for 9 and 16 MeV beams, against Monte Carlo (MC) simulations, point dosimetry in a water phantom and dose distributions calculated in virtual phantoms. For the 16 MeV beam, the accuracy of these algorithms was also compared over the lung-mediastinum interface region of an anthropomorphic phantom, against MC calculations and thermoluminescence dosimetry (TLD).

AutismPro system in supporting treatment of children with autism in Poland.

Background: The efficacy of early intervention programs for children with autism has been emphasized in many studies. However, access for people with autism to professional services in Poland is very limited and the burden of supporting a child's development often falls on parents, especially in families with low socioeconomic status and families living far away from big cities. Using Internet resources in planning and delivering individualized intervention may be useful.

The updated ESTRO core curricula 2011 for clinicians, medical physicists and RTTs in radiotherapy/radiation oncology.

Introduction: In 2007 ESTRO proposed a revision and harmonisation of the core curricula for radiation oncologists, medical physicists and RTTs to encourage harmonised education programmes for the professional disciplines, to facilitate mobility between EU member states, to reflect the rapid development of the professions and to secure the best evidence-based education across Europe.

Material And Methods: Working parties for each core curriculum were established and included a broad representation with geographic spread and different experience with education from the ESTRO Educational Committee, local representatives appointed by the National Societies and support from ESTRO staff.

Results: The revised curricula have been presented for the ESTRO community and endorsement is ongoing.

The application of amorphous track models to study cell survival in heavy ions beams.

In a study of amorphous track models, in the local effect model (LEM), the Kellerer algorithm was used, which folds radial dose distributions from different ion tracks. In representative set of 10 experimental cell survival curves of normal human skin fibroblast cells irradiated with carbon ions, the method that applies the Kellerer algorithm was found to be more accurate and 10(4) times faster than the usual Monte Carlo summation method based on a regular grid.

Application of IMRT in adjuvant treatment of soft tissue sarcomas of the thigh-Preliminary results.

Background: Fracture of the femur is the most frequent late complication in patients with soft tissue sarcomas (STS) who receive external beam radiotherapy after limb-sparing surgery.

Aim: To reduce the risk of bone fracture following radiotherapy of STS of the thigh, we minimized the dose to the femur and to surrounding normal tissues by applying intensity modulated radiation therapy (IMRT). We report preliminary results of post-surgery IMRT of the thigh in patients with STS in this extremity.

Track structure effects in a study of cell killing in normal human skin fibroblasts.

Purpose: To study track structure effects in cells irradiated by heavy ions, we have performed a model analysis of an extensive recently published data set of over 40 survival curves of normal human skin fibroblast cells irradiated in vitro by energetic carbon, neon, silicon and iron ions measured in track-segment conditions.

Materials And Methods: Having derived the required track-segment descriptions of the ion bombardments from the published data, we fitted four parameters of the cellular track structure theory (Katz model) to the whole data set.

Results: Using track structure calculations with the best-fitted parameters, we demonstrate a systematic interpretation of this data set, highlighting effects specific to track structure.

Two-dimensional dosimetry of radiotherapeutical proton beams using thermoluminescence foils.

In modern radiation therapy such as intensity modulated radiation therapy or proton therapy, one is able to cover the target volume with improved dose conformation and to spare surrounding tissue with help of modern measurement techniques. Novel thermoluminescence dosimetry (TLD) foils, developed from the hot-pressed mixture of LiF:Mg,Cu,P (MCP TL) powder and ethylene-tetrafluoroethylene (ETFE) copolymer, have been applied for 2-D dosimetry of radiotherapeutical proton beams at INFN Catania and IFJ Krakow. A TLD reader with 70 mm heating plate and CCD camera was used to read the 2-D emission pattern of irradiated foils.