GGEMS-Brachy: GPU GEant4-based Monte Carlo simulation for brachytherapy applications.

In brachytherapy, plans are routinely calculated using the AAPM TG43 formalism which considers the patient as a simple water object. An accurate modeling of the physical processes considering patient heterogeneity using Monte Carlo simulation (MCS) methods is currently too time-consuming and computationally demanding to be routinely used. In this work we implemented and evaluated an accurate and fast MCS on Graphics Processing Units (GPU) for brachytherapy low dose rate (LDR) applications.

[Acute coronary syndrome: guidelines and geriatrics specificity].

Acute coronary syndrome (ACS) includes unstable angina pectoris, myocardial infarction without ST elevation and myocardial infarction with ST elevation. ACS is more frequent in the elderly than in the general population and is associated with very high morbidity and mortality. As older individuals are often excluded from clinical trials, the geriatrician needs to take care of these subjects without specific guidelines.

[Prescribing psychotropic drugs to patients aged 80 and over].

The management of psychotropic drugs is a daily preoccupation for geriatric psychiatrists and geriatricians alike. The lack of controlled clinical trials in very old patients (over 80 years old) often leads to empirical therapy. The multiple somatic co-morbidities of old patients, the high prevalence of potential drug-drug interactions and a wish to implement an increasingly patient centered approach all influence psychotropic drug prescription which tends to be simplified and individualized.

[Amiodarone: treatment or cause of atrial fibrillation?].

Amiodarone has long been the anti-arrhythmic drug of choice for the treatment of atrial fibrillation. We use a clinical case report to illustrate the difficulty of treating this arrhythmia, which is frequent in older adults, by explaining the physiopathology of one of its side effects: hyperthyroidism. TSH should be measured in patients with recurrent atrial fibrillation under treatment in order to exclude an amiodarone-induced thyroid dysfunction.

[QT prolongation and inhibition of the P glycoprotein: presentation of 2 geriatric cases].

Two cases with QT prolongation associated with the administration of standard drug doses are reported. Drug effects are determined by pharmacological and biological parameters. Drugs may be metabolized or transported by two systems: the cytochrome enzymes or the less well-known but nevertheless relevant P-glycoprotein system.