Enhanced Cytotoxicity against a Pancreatic Cancer Cell Line Combining Radiation and Gold Nanoparticles.

The present work consisted of an exploratory study aiming to evaluate in vitro the potential of AuNPs during Radiation Therapy (RT) in human pancreatic adenocarcinoma cells. AuNPs coated with hyaluronic and oleic acids (HAOA-AuNPs) or with bombesin peptides (BBN-AuNPs) were used. AuNPs were characterized by Atomic Force Microscopy (AFM) and Dynamic Light Scattering.

Reflections on beam configuration optimization for intensity-modulated proton therapy.

Presumably, intensity-modulated proton radiotherapy (IMPT) is the most powerful form of proton radiotherapy. In the current state of the art, IMPT beam configurations (i.e.

SPIDERplan: A tool to support decision-making in radiation therapy treatment plan assessment.

Aim: In this work, a graphical method for radiotherapy treatment plan assessment and comparison, named SPIDERplan, is proposed. It aims to support plan approval allowing independent and consistent comparisons of different treatment techniques, algorithms or treatment planning systems.

Background: Optimized plans from modern radiotherapy are not easy to evaluate and compare because of their inherent multicriterial nature.

Assessment and topographic characterization of locoregional recurrences in head and neck tumours.

Purpose: To evaluate the differences between three methods of classification of recurrences in patients with head and neck tumours treated with Radiation Therapy (RT).

Materials And Methods: 367 patients with head and neck tumours were included in the study. Tumour recurrences were delineated in the CT images taken during patient follow-up and deformable registration was used to transfer this volume into the planning CT.

[Secondary hypothyroidism after cervical irradiation: systematic evaluation of thyroid function in follow-up].

Introduction: Sometimes Thyroid dysfunction is an underestimated consequence of radiation exposure. The underlying mechanism is not clearly understood, but it is likely to be multifactorial. As so, the specific risk factors associated with the development of secondary radiotherapy hypothyroidism remain undefined.

Beam angle optimization for intensity-modulated radiation therapy using a guided pattern search method.

Generally, the inverse planning of radiation therapy consists mainly of the fluence optimization. The beam angle optimization (BAO) in intensity-modulated radiation therapy (IMRT) consists of selecting appropriate radiation incidence directions and may influence the quality of the IMRT plans, both to enhance better organ sparing and to improve tumor coverage. However, in clinical practice, most of the time, beam directions continue to be manually selected by the treatment planner without objective and rigorous criteria.

Analysis of fractionation correction methodologies for multiple phase treatment plans in radiation therapy.

Purpose: Radiation therapy is often delivered by multiple sequential treatment plans. For an accurate radiobiological evaluation of the overall treatment, fractionation corrections to each dose distribution must be applied before summing the three-dimensional dose matrix of each plan since the simpler approach of performing the fractionation correction to the total dose-volume histograms, obtained by the arithmetical sum of the different plans, becomes inaccurate for more heterogeneous dose patterns. In this study, the differences between these two fractionation correction methods, named here as exact (corrected before) and approximate (after summation), respectively, are assessed for different cancer types.

Response-probability volume histograms and iso-probability of response charts in treatment plan evaluation.

Purpose: This study aims at demonstrating a new method for treatment plan evaluation and comparison based on the radiobiological response of individual voxels. This is performed by applying them on three different cancer types and treatment plans of different conformalities. Furthermore, their usefulness is examined in conjunction with traditionally applied radiobiological and dosimetric treatment plan evaluation criteria.

Radiobiological evaluation of forward and inverse IMRT using different fractionations for head and neck tumours.

Purpose: To quantify the radiobiological advantages obtained by an Improved Forward Planning technique (IFP) and two IMRT techniques using different fractionation schemes for the irradiation of head and neck tumours. The conventional radiation therapy technique (CONVT) was used here as a benchmark.

Methods: Seven patients with head and neck tumours were selected for this retrospective planning study.

A graphic user interface toolkit for specification, report and comparison of dose-response relations and treatment plans using the biologically effective uniform dose.

A toolkit (BEUDcal) has been developed for evaluating the effectiveness and for predicting the outcome of treatment plans by calculating the biologically effective uniform dose (BEUD) and complication-free tumor control probability. The input for the BEUDcal is the differential dose-volume histograms of organs exported from the treatment planning system. A clinical database is built for the dose-response parameters of different tumors and normal tissues.

Comparison of the helical tomotherapy and MLC-based IMRT radiation modalities in treating brain and cranio-spinal tumors.

The investigation of the clinical efficacy and effectiveness of Intensity Modulated Radiotherapy (IMRT) using Multileaf Collimators (MLC) and Helical Tomotherapy (HT) has been an issue of increasing interest over the past few years. In order to assess the suitability of a treatment plan, dosimetric criteria such as dose-volume histograms (DVH), maximum, minimum, mean, and standard deviation of the dose distribution are typically used. Nevertheless, the radiobiological parameters of the different tumors and normal tissues are often not taken into account.

The impact of different dose-response parameters on biologically optimized IMRT in breast cancer.

The full potential of biologically optimized radiation therapy can only be maximized with the prediction of individual patient radiosensitivity prior to treatment. Unfortunately, the available biological parameters, derived from clinical trials, reflect an average radiosensitivity of the examined populations. In the present study, a breast cancer patient of stage I-II with positive lymph nodes was chosen in order to analyse the effect of the variation of individual radiosensitivity on the optimal dose distribution.

Treatment plan comparison between helical tomotherapy and MLC-based IMRT using radiobiological measures.

The rapid implementation of advanced treatment planning and delivery technologies for radiation therapy has brought new challenges in evaluating the most effective treatment modality. Intensity-modulated radiotherapy (IMRT) using multi-leaf collimators (MLC) and helical tomotherapy (HT) are becoming popular modes of treatment delivery and their application and effectiveness continues to be investigated. Presently, there are several treatment planning systems (TPS) that can generate and optimize IMRT plans based on user-defined objective functions for the internal target volume (ITV) and organs at risk (OAR).

Effective beam directions using radiobiologically optimized IMRT of node positive breast cancer.

The purpose of this study was to investigate the optimal coplanar beam directions when treating an early breast cancer with locoregional lymphatic spread with a few radiobiologically optimized intensity modulated beams. Also to determine the increase in the probability of complication-free cure with the number of beam portals and the smallest number required to perform a close to optimal treatment for this tumour site. Four test patients with stage II left-sided breast cancer were studied with heart, lung and contralateral breast as principal organs at risk.

The clinical value of non-coplanar photon beams in biologically optimized intensity modulated dose delivery on deep-seated tumours.

The aim of the present study is to compare the merits of different radiobiologically optimized treatment techniques using few-field planar and non-coplanar dose delivery on an advanced cancer of the cervix, with rectum and bladder as principal organs at risk. Classically, the rational for using non-coplanar beams is to minimize the overlap of beam entrance and exit regions and to find new beam directions avoiding organs at risk, in order to reduce damage to sensitive normal tissues. Two four-beam configurations have been extensively studied.