Adaptive biokinetic modelling of iodine-131 in thyroid cancer treatments: implications on individualised internal dosimetry.

Nowadays therapies involving radioiodine (I-131) represent 84% of the total metabolic treatments in Europe, according to the last report of the European Association of Nuclear Medicine in relation to treatment planning for molecular radiotherapy. Last recommendations of the European Council, i.e. 2013/59/Euroatom, mandates that metabolic treatments should be planned according to the radiation doses delivered to individual patients, analogous to external beam radiotherapy. In this work, we present a novel biokinetic model for I-131 that allows on to obtain realistic activity distributions for particular patients with thyroid cancer in absence of metastasis. Other models existing in the literature present either a too simple metabolic description to obtain realistic results or a too complex one for adapting the model to individual patients, and many of these models are not indicated for metabolic treatments. The individualisation of activity distribution is obtained by an optimisation method that adjusts our model to a set of experimental measurements. Significant differences in terms of absorbed doses are observed between our model and the standard generalist models, especially in terms of red marrow absorbed dose.

Characterising endourologist learning curve during percutaneous nephrolithotomy: implications on occupational dose and patients.

In this study we have characterised the learning curve for percutaneous nephrolithotomy procedures over 301 cases for six years. Different surrogate parameters of clinical expertise have been used, such as dose area product, total procedure time, fluoroscopy time and personal equivalent doses. In addition, two different endourologists have been monitored; one of whom had specific Radiation Protection training (ICRP 85). Eye lens dose was estimated from thermoluminescent dosimeters. Significant differences were observed between both endourologists, especially in the fluoroscopy time. Finally, both entrance skin dose and effective doses of patients have been determined.

Evaluation and optimization of occupational eye lens dosimetry during positron emission tomography (PET) procedures.

The last recommendations of the International Commission on Radiological Protection for eye lens dose suggest an important reduction on the radiation limits associated with early and late tissue reactions. The aim of this work is to quantify and optimize the eye lens dose associated to nurse staff during positron emission tomography (PET) procedures. PET is one of the most important diagnostic methods of oncological and neurological cancer disease involving an important number of workers exposed to the high energy isotope F-18. We characterize the relevant stages as preparation and administration of monodose syringes in terms of occupational dose. A direct reading silicon dosimeter was used to measure the lens dose to staff. The highest dose of radiation was observed during preparation of the fluorodesoxyglucose (FDG) syringes. By optimizing a suitable vials' distribution of FDG we find an important reduction in occupational doses. Extrapolation of our data to other clinical scenarios indicates that, depending on the work load and/or syringes activity, safety limits of the dose might be exceeded.

Monte Carlo verification of IMRT treatment plans on grid.

The eIMRT project is producing new remote computational tools for helping radiotherapists to plan and deliver treatments. The first available tool will be the IMRT treatment verification using Monte Carlo, which is a computational expensive problem that can be executed remotely on a GRID. In this paper, the current implementation of this process using GRID and SOA technologies is presented, describing the remote execution environment and the client.

Remote radiotherapy planning: the eIMRT project.

In this paper, we present the eIMRT project which is currently carried out by diverse institutions in Galicia (Spain) and the USA. The eIMRT project will offer radiotherapists a set of algorithms to optimize and validate radiotherapy treatments, both CRT- and IMRT-based, hiding the complexity of the computer infrastructure needed to solve the problem using GRID technologies. The new platform is designed to be independent from the medical accelerator models, scalable and open. Having a web portal as client, it is designed in three layers using web services, which will allow users to access the platform directly from any front-end and client. It has three main components, namely remote characterization of linear accelerators for Monte Carlo and convolution/superposition (C/S) dose-calculation techniques, remote Grid-enabled radiotherapy treatment planning optimization and verification and data depository.