A motion model-guided 4D dose reconstruction for pencil beam scanned proton therapy.

Objective.4D dose reconstruction in proton therapy with pencil beam scanning (PBS) typically relies on a single pre-treatment 4DCT (p4DCT). However, breathing motion during the fractionated treatment can vary considerably in both amplitude and frequency. We present a novel 4D dose reconstruction method combining delivery log files with patient-specific motion models, to account for the dosimetric effect of intra- and inter-fractional breathing variability.Approach.Correlation between an external breathing surrogate and anatomical deformations of the p4DCT is established using principal component analysis. Using motion trajectories of a surface marker acquired during the dose delivery by an optical tracking system, deformable motion fields are retrospectively reconstructed and used to generate time-resolved synthetic 4DCTs ('5DCTs') by warping a reference CT. For three abdominal/thoracic patients, treated with respiratory gating and rescanning, example fraction doses were reconstructed using the resulting 5DCTs and delivery log files. The motion model was validated beforehand using leave-one-out cross-validation (LOOCV) with subsequent 4D dose evaluations. Moreover, besides fractional motion, fractional anatomical changes were incorporated as proof of concept.Main results.For motion model validation, the comparison of 4D dose distributions for the original 4DCT and predicted LOOCV resulted in 3%/3 mm gamma pass rates above 96.2%. Prospective gating simulations on the p4DCT can overestimate the target dose coverage V95%by up to 2.1% compared to 4D dose reconstruction based on observed surrogate trajectories. Nevertheless, for the studied clinical cases treated with respiratory-gating and rescanning, an acceptable target coverage was maintained with V95%remaining above 98.8% for all studied fractions. For these gated treatments, larger dosimetric differences occurred due to CT changes than due to breathing variations.Significance.To gain a better estimate of the delivered dose, a retrospective 4D dose reconstruction workflow based on motion data acquired during PBS proton treatments was implemented and validated, thus considering both intra- and inter-fractional motion and anatomy changes.

Dynamic beam current control for improved dose accuracy in PBS proton therapy.

The step-and-shoot method of pencil beam scanning delivers the dose on a 3D grid in the target volume, with one dimension defined by the proton energy. While the dose per pencil beam may vary substantially within an iso-energy layer, the beam current typically remains constant. In this static operation mode, the inherent latency of the beam switch-off mechanism results in a lower limit for the deliverable spot dose, which may prevent the application of some of the low-weighted spots prescribed by the treatment planning system. To overcome this limitation, we introduced dynamic beam current control at the PSI Gantry 2, an innovative new approach successfully commissioned and in clinical operation since fall 2017. The control system was enhanced with a direct link to the vertical deflector located at the centre of the cyclotron. This connection allows much faster beam current changes (~0.1 ms) and hence opens up the possibility of dynamically reducing the current for individual low-dose spots. We demonstrate that with this new dynamic operation mode, all spots are delivered as planned without compromising treatment time. We show by two independent and complementary methods that the delivered dose distribution is improved.

Geriatric palliative care: a view of its concept, challenges and strategies.

In aging societies, the last phase of people's lives changes profoundly, challenging traditional care provision in geriatric medicine and palliative care. Both specialties have to collaborate closely and geriatric palliative care (GPC) should be conceptualized as an interdisciplinary field of care and research based on the synergies of the two and an ethics of care.Major challenges characterizing the emerging field of GPC concern (1) the development of methodologically creative and ethically sound research to promote evidence-based care and teaching; (2) the promotion of responsible care and treatment decision making in the face of multiple complicating factors related to decisional capacity, communication and behavioural problems, extended disease trajectories and complex social contexts; (3) the implementation of coordinated, continuous care despite the increasing fragmentation, sectorization and specialization in health care.Exemplary strategies to address these challenges are presented: (1) GPC research could be enhanced by specific funding programs, specific patient registries and anticipatory consent procedures; (2) treatment decision making can be significantly improved using advance care planning programs that include adequate decision aids, including those that address proxies of patient who have lost decisional capacity; (3) care coordination and continuity require multiple approaches, such as care transition programs, electronic solutions, and professionals who act as key integrators.

A beam monitoring and validation system for continuous line scanning in proton therapy.

Line scanning represents a faster and potentially more flexible form of pencil beam scanning than conventional step-and-shoot irradiations. It seeks to minimize dead times in beam delivery whilst preserving the possibility of modulating the dose at any point in the target volume. Our second generation proton gantry features irradiations in line scanning mode, but it still lacks a dedicated monitoring and validation system that guarantees patient safety throughout the irradiation. We report on its design and implementation in this paper. In line scanning, we steer the proton beam continuously along straight lines while adapting the speed and/or current frequently to modulate the delivered dose. We intend to prevent delivery errors that could be clinically relevant through a two-stage system: safety level 1 monitors the beam current and position every 10 µs. We demonstrate that direct readings from ionization chambers in the gantry nozzle and Hall probes in the scanner magnets provide required information on current and position, respectively. Interlocks will be raised when measured signals exceed their predefined tolerance bands. Even in case of an erroneous delivery, safety level 1 restricts hot and cold spots of the physically delivered fraction dose to ±[Formula: see text] (±[Formula: see text] of [Formula: see text] biologically). In safety level 2-an additional, partly redundant validation step-we compare the integral line profile measured with a strip monitor in the nozzle to a forward-calculated prediction. The comparison is performed between two line applications to detect amplifying inaccuracies in speed and current modulation. This level can be regarded as an online quality assurance of the machine. Both safety levels use devices and functionalities already installed along the beamline. Hence, the presented monitoring and validation system preserves full compatibility of discrete and continuous delivery mode on a single gantry, with the possibility of switching between modes during the application of a single field.

Universal screening and decolonization for control of MRSA in nursing homes: follow-up of a cluster randomized controlled trial.

In 2010-11, a trial conducted in nursing homes showed no benefit of meticillin-resistant Staphylococcus aureus (MRSA) universal screening and decolonization over standard precautions to reduce the prevalence of MRSA carriage. Accordingly, no routine screening was performed from 2012. A five-year follow-up shows no new evidence supporting the intervention. Recommendations issued after trial (no screening and decolonization of MRSA residents) were retained.

Association between Physical Frailty and Quality of Life in a Representative Sample of Community-Dwelling Swiss Older People.

OBJECTIVE: Though the association between physical frailty and health is well established, little is known about its association with other domains of quality of life (QoL). This study investigated the association between physical frailty and multiple domains of QoL in community-dwelling older people. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: Data of the 2011 annual assessment of 927 older people (age 73-77 years) from the Lc65+ cohort study were used. MEASUREMENTS: Physical frailty was assessed by Fried's five criteria: 'shrinking'; 'weakness'; 'poor endurance, exhaustion'; 'slowness'; and 'low activity'. QoL was assessed using 28 items yielding a QoL score and seven domain-specific QoL subscores (Feeling of safety; Health and mobility; Autonomy; Close entourage; Material resources; Esteem and recognition; and Social and cultural life). Low QoL (QoL score or QoL subscores in the lowest quintile) was used as dependent variable in logistic regression analyses adjusted for age and sex (model 1), and additionally for socioeconomic (model 2) and health (model 3) covariates. RESULTS: Physical frailty was associated with a low QoL score, as well as decreased QoL subscores in all seven specific domains, even after adjusting for socio-economic covariates. However, when performing additional adjustment for health covariates, only the domain Health and mobility remained significantly associated with physical frailty. Among each specific Fried's criteria, 'slowness' had the strongest association with a low QoL score. CONCLUSION: Physical frailty is associated with all QoL domains, but these associations are largely explained by poor health characteristics. Longitudinal studies are needed to better understand temporal relationships between physical frailty, health and QoL.

[Urinary incontinence in older women: what can a GP do?]. / Incontinence urinaire chez la femme âgée: que faire au cabinet?

Urinary incontinence (UI) is frequent in older women but remains often neglected when they consult their physician. It is associated with numerous health and social consequences that impact on these older persons' quality of life, as well as on their health care costs. Primary care physicians should become more familiar with this frequent condition. A clinical pathway is proposed to guide them in diagnosing and managing of this debilitating condition.

[Nutritional assessment in primary practice in elderly patients]. / Approche ambulatoire de la dénutrition chez la personne âgée.

Undernutrition is frequent and often underdiagnosed among older adults in every setting (home, nursing home, hospital), and is associated with increased morbidity and mortality. In this context, a systematic periodical nutritional assessment is proposed in patients aged 75 years and over. Without a consensus, the most widely used diagnostic criteria is an unintentional weight loss of 5% over a month or 10% over 6 months. When undernutrition is present, multimodal interventions are provided to address each potentially contributing comorbid condition and to promote increased caloric intake. Follow-up and adaptation of interventions after 3 months are required.

[Vulnerable older patients in primary care how to identify them? Which ressources to mobilize? ]. / Patients âgées vulnérables au cabinet: comment les identifier et quelles ressources mobiliser?

Trust is essential to foster and preserve a long-term relationship between primary care physicians and their patients suffering from chronic diseases. However, this relation remains insufficient to successfully manage more complex situations, such as those of older patients with multiple diseases and disability. For the primary care physician, a significant limitation is the time required to plan and coordinate interventions supplied by different health and social care providers. This article describes a structured approach to support primary care physicians in this difficult task and help them to identify vulnerable older patients requiring to mobilize and coordinate health and social care resources. Current and future resources available to family physicians to complete this challenging task are further described.

[Diabetes and dementia: the dangerous liaisons? ]. / Diabéte et démence: tes liaisons dangereuses?

As population ages, a growing number of older patients present the constellation of diabetes and dementia. Numerous recent studies highlight that diabetes may increase the risk for Alzheimer and vascular dementia. Among patients with previous severe hypoglycemia, that risk may even double. Inversely demented patients have about three times higher risk of hypoglycemia. Given that spiral link between hypoglycemia and dementia, the latter should be considered as a possible complication of diabetes and consistently be screened for among older diabetic patients. Furthermore, the American Diabetes Association and American Geriatric Society consensus recommends a more flexible glycemic treatment goal of AIC among demented patients, with a target range between 8 and 9%.

[Preoperative assessment in elderly patients]. / Evaluation préopératoire des patients ages.

Age-related physiological changes and comorbidities affect older patients' tolerance to surgery. Pre-operative assessment in these patients requires, beside the usual physical evaluation, the systematic screening of common geriatric syndromes. Cognitive, gait and balance, nutritional, and functional impairments, all flag patients at higher risk for per- and postoperative complications. Preoperative assessment is an opportunity to detect these syndromes and propose preventative interventions (physical therapy, nutritional and cognitive support measures) likely to reduce the incidence of postoperative morbidity.

Alcohol Use and Frailty in Community-Dwelling Older Persons Aged 65 to 70 Years.

BACKGROUND: Alcohol use has beneficial as well as adverse consequences on health, but few studies examined its role in the development of age-related frailty. OBJECTIVES: To describe the cross-sectional and longitudinal association between alcohol intake and frailty in older persons. DESIGN: The Lausanne cohort 65+ population-based study, launched in 2004. SETTING: Community. PARTICIPANTS: One thousand five hundred sixty-four persons aged 65-70 years. MEASUREMENTS: Annual data collection included demographics, health and functional status, extended by a physical examination every 3 years. Alcohol use (AUDIT-C), and Fried's frailty criteria were measured at baseline and 3-year follow-up. Participants were categorized into robust (0 frailty criterion) and vulnerable (1+ criteria). RESULTS: Few participants (13.0%) reported no alcohol consumption over the past year, 57.8% were light-to-moderate drinkers, while 29.3% drank above recommended thresholds (18.7% "at risk" and 10.5% "heavy" drinkers). At baseline, vulnerability was most frequent in non-drinkers (43.0%), least frequent in light-to-moderate drinkers (26.2%), and amounted to 31.9% in "heavy" drinkers showing a reverse J-curve pattern. In multivariate analysis, compared to light-to-moderate drinkers, non-drinkers had twice higher odds of prevalent (adjOR: 2.24; 95%CI:1.39-3.59; p=.001), as well as 3-year incident vulnerability (adjOR: 2.00; 95%CI:1.02-3.91; p=.043). No significant association was observed among "at risk" and "heavy" drinkers. CONCLUSION: Non-drinkers had two-times higher odds of prevalent and 3-year incident vulnerability, even after adjusting for their baseline poorer health status. Although residual confounding is still possible, these results likely reflect a healthy survival effect among drinkers while those who experienced health- or alcohol-related problems stopped drinking earlier.

[Consensus 2012--diagnosis and treatment of patients with dementia in Switzerland]. / Consensus 2012 sur le diagnostic et le traitement des patients atteints de démence en Suisse.

The 2012 Swiss consensus paper on diagnosis and management of patients suffering from dementia resulted from the work of an expert panel who met on March 23d to 25th in Luzem. Based on a literature review, panel members wrote a first draft that was subsequently circulated among multiple dementia experts in Switzerland. After adaptation and revisions according to comments, all consulted dementia specialists and panel members fully endorse the consensus content. The conference was financed by the Swiss Alzheimer Forum.

[Review in geriatric medicine 2012]. / Gériatrie.

2012 brought additional evidence regarding the benefits of exercise in older persons in showing morbidity compression in those most active. Several studies invite to revise therapeutic targets in older diabetics, especially those with cognitive impairment or dementia where a value of 8 to 9% for HbAlc might be a good compromise. On the dementia side, a study suggests that biological and structural abnormalities associated with Alzheimer's disease might occur as early as 25 years before its first clinical manifestations. On the therapeutic side, ginkgo and the double therapy with memantine and donepezil did not make it in RCTs, and two studies about treatments for behavioral symptoms of dementia showed that interruption could be deleterious.

[Older patients at the emergency department: current and future challenges]. / Personnes âgées aux urgences: défis actuels et futurs.

Emergency departments are and will be at the front line to face the forthcoming increased use of the health care system by the aging baby boomers cohort. Emergency department services will need to adjust on a quantitative as well as on a qualitative basis to manage the impact of these demographic changes. Various models of care have been developed to improve the care of older geriatric patients in the Emergency department that resulted in favorable results on functional, health, as well as health services utilization outcomes. Key components of these successful models have been identified that require a high level of integration between geriatric and emergency teams.

[Older people admitted to the emergency department after a fall: what to do?]. / Patients âgés admis aux urgences suite à une chute: que faire?

Falls in older people are frequent. Falls may lead to serious injuries and are associated with greater morbidity, mortality, and reduced overall functioning in the older population. Evidences exist regarding the beneficial effects of fall prevention programs. However, these interventions are rarely implemented in our health system. Older people admitted to the emergency department after a fall should get careful attention in order to initiate specific interventions to prevent new falls. This article provides a clinical assessment strategy to evaluate older persons after a fall and proposes an algorithm for discharge planning decision.

[Promotion of exercise in older people: issues and strategies]. / Promotion de l'activité physique chez les aînés: enjeux et stratégies spécifiques.

Regular physical activity is among the most effective interventions to prevent or delay functional decline and disability, even in older persons. Despite relatively strong scientific evidence supporting these benefits, the majority of older persons remain mostly sedentary. For these persons, concerns about injury or fear of negative consequences on their chronic diseases are among the most powerful barriers to participation in regular physical activity. Promotion of physical activity among older persons has therefore become one of the five main themes of the health promotion project "Via", a project that aims at promoting good practice in prevention and health promotion directed toward older adults in Switzerland. This paper summarizes the main recommendations issued from this national project supported by the Swiss Health Promotion Foundation.

[Review in geriatric medicine 2011]. / Gériatrie.

In 2011, new tools to evaluate life expectancy are available. Controversy about PSA-based screening for prostate cancer is still going on, with new data from the US Preventive services task force. A brief behavioral treatment for insomnia can be efficient and durable. Gliptines are be useful to avoid treatment-induced hypoglycemia in diabetic patients. New Alzheimer diagnostic criteria, including biomarkers, have been published.