Intraoperative computed tomography imaging for dose calculation in intraoperative electron radiation therapy: Initial clinical observations

In intraoperative electron radiation therapy (IOERT) the energy of the electron beam is selected under the conventional assumption of water-equivalent tissues at the applicator end. However, the treatment field can deviate from the theoretic flat irradiation surface, thus altering dose profiles. This patient-based study explored the feasibility of acquiring intraoperative computed tomography (CT) studies for calculating three-dimensional dose distributions with two factors not included in the conventional assumption, namely the air gap from the applicator end to the irradiation surface and tissue heterogeneity. In addition, dose distributions under the conventional assumption and from preoperative CT studies (both also updated with intraoperative data) were calculated to explore whether there are other alternatives to intraoperative CT studies that can provide similar dose distributions. The IOERT protocol was modified to incorporate the acquisition of intraoperative CT studies before radiation delivery in six patients.This study was supported by Ministerio de Ciencia, Innovación y Universidades (http://www.ciencia.gob.es) [grant number TEC2013–48251-C2 to JP, VG-V and MJL-C], co-funded by European Regional Development Fund (ERDF), “A way of making Europe” (https://ec.europa.eu/regional_policy/en/funding/erdf); by Ministerio de Ciencia, Innovación y Universidades (http://www.ciencia.gob.es), Instituto de Salud Carlos III (https://www.isciii.es) [grant numbers DTS14/00192 to JP, VG-V and FAC; PI15/02121 to FAC and JC-H; PI18/01625 to JP], co-funded by European Regional Development Fund (ERDF), “A way of making Europe” (https://ec.europa.eu/regional_policy/en/funding/erdf); and by Comunidad de Madrid (http://www.comunidad.madrid) [grant number TOPUS-CM S2013/MIT3024 to JP], co-funded by European Structural and Investment Fund (https://ec.europa.eu/info/funding-tenders/funding-opportunities/funding-programmes/overview-funding-programmes_en). The CNIC is supported by the Ministerio de Ciencia, Innovación y Universidades (http://www.ciencia.gob.es) and the Pro CNIC Foundation (https://www.fundacionprocnic.es) [to MD], and is a Severo Ochoa Center of Excellence (SEV-2015-0505). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Valor pronóstico de la radioterapia externa en el tratamiento multidisciplinar de pacientes con cáncer oligo-recurrente loco-regional

En el contexto de la oligo-recurrencia loco-regional, se han investigado nuevos factores pronósticos y resultados de supervivencia a largo plazo en un amplio grupo de pacientes en instituciones académicas con cirugía resectiva seguida de radioterapia intraoperatoria (RIO) con haz de electrones administrada zonas de alto riesgo (lecho quirúrgico post-resección y pre-reconstrucción) con o sin radioterapia externa con fotones (RTE). La madurez evolutiva, el tamaño muestral de los distintos subtipos histológicos, la homogeneidad diagnóstica y de los componentes terapéuticos empleados en instituciones expertas en estrategias de rescate oncológico intensificado, convierten el presente análisis clínico-terapéutico en la experiencia oncológica más sistematizada y extensa de cáncer oligo-recurrente. Los pacientes con oligo-recurrencia loco- regional pertenecientes a diferentes modelos clínico-patológicos que recibieron RTE y RIO lograron mejores resultados oncológicos a largo plazo sin un aumento en la toxicidad. El dato más original evaluado respecto al riesgo de recidiva local es la fragmentación tumoral. Las resecciones R0 experimentaron el mayor beneficio con el tratamiento con RTE. No obstante, un cierto nivel de adversidad pronóstico (resecciones R1) puede ser compensada en un contexto de máxima intensidad terapéutica. Por último, la terapia sistémica adyuvante no contribuyó de forma relevante en el abordaje radical de estos pacientes en los períodos de tiempo evaluados. Sin embargo, debido a que las metástasis sistémicas son un patrón de progresión frecuente en pacientes oligo-recurrentes, el desarrollo de terapias sistémicas más efectivas jugará un papel decisivo en el progreso terapéutico de estos pacientes. La terapia sistémica neo-adyuvante, concomitante y adyuvante en diferentes combinaciones con terapia local intensificada tiene un fundamento conceptual que debe ser probado en el escenario metodológico de un ensayo clínico. El futuro de la investigación clínica debe centrarse en la intensificación loco-regional en sub-volúmenes de riesgo, en la promoción del resultado anatómico-funcional favorable y en la minimización de secuelas que comprometan la calidad de vida

XMI-MSIM 5.0

<p>XMI-MSIM is an open source tool designed for predicting the spectral response of energy-dispersive X-ray fluorescence spectrometers using Monte-Carlo simulations. It comes with a fully functional graphical user interface in order to make it as user friendly as possible. Considerable effort has been taken to ensure easy installation on all major platforms.</p> <p>Development of this package was part of my PhD thesis. The algorithms were inspired by the work of my promotor Prof. Laszlo Vincze of Ghent University. Links to his and my own publications can be found in our manual.</p> <p>A manuscript has been published in Spectrochimica Acta Part B that covers the algorithms that power XMI-MSIM. Please include a reference to this publication in your own work if you decide to use XMI-MSIM for academic purposes.</p> <p>A second manuscript was published that covers our XMI-MSIM based quantification plug-in for PyMca. Soon information on using this plug-in will be added to the manual.</p> <p>XMI-MSIM is released under the terms of the GPLv3.</p> <p>Development occurs at Github: http://github.com/tschoonj/xmimsim<br> Downloads are hosted by the X-ray Micro-spectroscopy and Imaging research group of Ghent University: http://lvserver.ugent.be/xmi-msim</p> <p>Version 5.0 release notes:</p> <p>Changes:</p> <ol> <li>Custom detector response function: build a own plug-in containing your own detector response function and load it at run-time to override the builtin routines. Instructions can be found in the manual.</li> <li>Escape peak improvements: new algorithm is used to calculate the escape peak ratios based on a combined brute-force and variance-reduction approach. Ensures high accuracy even at high incoming photon energies and thin detector crystals. Downside: it's slower…</li> <li>Removed maximum convolution energy option. Was a bit confusing anyway.</li> <li>Number of channels: moved from simulation controls into input-file</li> <li>Radionuclide support added: Now you can select one or more commonly used radionuclide sources from the X-ray sources widget.</li> <li>Advanced Compton scattering simulation: a new alternative implementation of the Compton scattering has been implemented based on the work of Fernandez and Scot (http://dx.doi.org/10.1016/j.nimb.2007.04.203), which takes into account unpopulated atomic orbitals. Provides an improved simulation of the Compton profile, as well as fluorescence contributions due to Compton effect (extremely low!), but slows the code down considerably. Advanced users only. Default: OFF</li> <li>Plot spectra before convolution in results</li> <li>Windows: new Inno Setup installers. Contains the headers and import libraries</li> <li>Windows: compilers changed to GCC 4.8.1 (TDM-GCC)</li> <li>Windows: rand_s used to generate seeds on 64-bit version (requires Vista or later)</li> <li>Windows: new gtk runtime for the 64-bit version (see also https://github.com/tschoonj/GTK-for-Windows-Runtime-Environment-Installer)</li> <li>Mac OS X: compilers changed to clang 5.1 (Xcode) and gfortran 4.9.1 (MacPorts)</li> <li>Original input-files from our 2012 publication (http://dx.doi.org/10.1016/j.sab.2012.03.011) added to examples</li> <li>Updater performs checksum verification after download</li> <li>X-ray sources last used values stored in preferences.ini</li> <li>xmimsimdata.h5 modified: even bigger now...</li> </ol> <p> </p> <p>Bugfixes:</p> <ol> <li>Windows: support for usernames with unicode characters. Fixed using customized builds of HDF5. Thanks to Takashi Omori of Techno-X for the report!</li> <li>Spectrum import from file fixes. Was never properly tested apparently</li> </ol> <p> </p> <p>Note:<br> For those that compiled XMI-MSIM from source: you will need to regenerate the xmimsimdata.h5 file with xmimsim-db. Old versions of this file will not work with XMI-MSIM 5.0.</p> <p> </p> <p> </p

Assessment of intraoperative 3D imaging alternatives for IOERT dose estimation

Intraoperative electron radiation therapy (IOERT) involves irradiation of an unresected tumour or a post-resection tumour bed. The dose distribution is calculated from a preoperative computed tomography (CT) study acquired using a CT simulator. However, differences between the actual IOERT field and that calculated from the preoperative study arise as a result of patient position, surgical access, tumour resection and the IOERT set-up. Intraoperative CT imaging may then enable a more accurate estimation of dose distribution. In this study, we evaluated three kilovoltage (kV) CT scanners with the ability to acquire intraoperative images. Our findings indicate that current IOERT plans may be improved using data based on actual anatomical conditions during radiation. The systems studied were two portable systems (“O-arm”, a cone-beam CT [CBCT] system, and “BodyTom”, a multislice CT [MSCT] system) and one CBCT integrated in a conventional linear accelerator (LINAC) (“TrueBeam”). TrueBeam and BodyTom showed good results, as the gamma pass rates of their dose distributions compared to the gold standard (dose distributions calculated from images acquired with a CT simulator) were above 97% in most cases. The O-arm yielded a lower percentage of voxels fulfilling gamma criteria owing to its reduced field of view (which left it prone to truncation artefacts). Our results show that the images acquired using a portable CT or even a LINAC with on-board kV CBCT could be used to estimate the dose of IOERT and improve the possibility to evaluate and register the treatment administered to the patient