Medicosocial outcome after admission in post-intensive care unit at PRM St-Hélier, Rennes

IntroductionPost-Intensive Care Units (PICU) are PRM structures aiming to start the appropriated rehabilitative care as early as possible even though persistent complex medical issues.ObjectiveTo assess medicosocial outcomes of patients away from their admission in PICU.MethodsA retrospective descriptive study that included 81 consecutive patients (mean age 51 years) admitted from 2008 to 2012 in the PICU of Pôle St-Helier Rennes based on called semi-structured interviews between March 2014 and March 2015. Exhaustive data (only 4 lost, 5%) by the patient himself and/or a member of family on autonomy, place of life, structures since the release and reintegration, of patients for 85% of them brain damaged.ResultsThere is 29% (21/77) of death (post-exit life: 1,6 years±1.18). Eighty percent live at home (46/56) of which only 5 without family environment, 10% (5/56) in medicosocial structures (foster or nursing homes…), 10% in hospital (hospital at home, persistent vegetative units…). Fourteen percent (8/56) are completely autonomous and work, all with adaptations. Twenty-three percent (13/56) had a significant dependence for activities of daily life and instrumental ones. Forty percent (22/56) have no hobby. Use of different downstream structures, long-term readaptative monitoring, legal and families’ feelings were also analyzed.Discussion and ConclusionMedical and social outcome of patients in the aftermath of a stay in PICU is disparate, depending on the pathology involved, but also the pre-social situation that seems to be the main predictor of returning home. Most patients have regained a relatively large autonomy for the daily life activities but are embarrassed to complex instrumental activities impeding social inclusion. These results are consistent with those of the literature on head trauma patients but no other study has focused for the moment on the specific population of patients admitted to the PICU. We see the value of such early rehabilitative care units with a real impact on the subsequent independence and opportunities back home

Design of experiments in medical physics: Application to the AAA beam model validation

Purpose The purpose of this study is to evaluate the usefulness of the design of experiments in the analysis of multiparametric problems related to the quality assurance in radiotherapy. The main motivation is to use this statistical method to optimize the quality assurance processes in the validation of beam models. Method Considering the Varian Eclipse system, eight parameters with several levels were selected: energy, MLC, depth, X, Y1 and Y2 jaw dimensions, wedge and wedge jaw. A Taguchi table was used to define 72 validation tests. Measurements were conducted in water using a CC04 on a TrueBeam STx, a TrueBeam Tx, a Trilogy and a 2300IX accelerator matched by the vendor. Dose was computed using the AAA algorithm. The same raw data was used for all accelerators during the beam modelling. Results The mean difference between computed and measured doses was 0.1 ± 0.5% for all beams and all accelerators with a maximum difference of 2.4% (under the 3% tolerance level). For all beams, the measured doses were within 0.6% for all accelerators. The energy was found to be an influencing parameter but the deviations observed were smaller than 1% and not considered clinically significant. Conclusion Designs of experiment can help define the optimal measurement set to validate a beam model. The proposed method can be used to identify the prognostic factors of dose accuracy. The beam models were validated for the 4 accelerators which were found dosimetrically equivalent even though the accelerator characteristics differ

Mise en place de la Maîtrise Statistique des Procédés pour les contrôles pré-traitement par imagerie portale pour la technique VMAT

National audienc

A new robust statistical method for treatment planning systems validation using experimental designs

Introduction Dose computation verification is an important part of acceptance testing. The IAEA Tecdoc 1540 and 1583 suggest comparing computed dose to measurements for several beam configurations. However, this process is time-consuming and results out of tolerance are often left unexplained. Purpose To validate a treatment planning system using experimental designs which allow evaluating several parameters in a few tests selected by a robust statistical method. Materials and methods The Taguchi table L36 (211 × 312) was used to determine the 72 beams needed to test the 7 parameters chosen: energy, MLC, depth, jaw field size in X, Y1 and Y2 directions and wedge. Measurements were conducted in water using a CC04 (IBA) on a TrueBeam STx, a TrueBeam Tx, a Trilogy and a C-serie clinac (Varian). Dose was computed using the AAA algorithm (Eclipse, version 11). The same raw data was used for all accelerators during the algorithm configuration. Results The mean difference between computed and measured doses was 0.1 ±± 0.5% for all tested beams and all linacs with a maximum difference of 2.4% (under the 3% tolerance level). For all beams, the measured doses were within 0.6% for all linacs. No studied parameter led to statistically significant deviation between computed and measured doses. Conclusion Experimental design is a robust statistical method to validate an algorithm. Only 2 h of measurements were needed to evaluate 7 parameters. Furthermore, the commissioned accelerators were found dosimetrically equivalent even though the linac characteristics differ