Electron microscopy of biological, polymeric, and other beam-sensitive structures is often hampered by deleterious electron beam interactions. In fact, imaging of such beam-sensitive materials is limited by the allowable radiation dosage rather that capabilities of the microscope itself, which has been compounded by the availability of high brightness electron sources. Reducing dwell times to overcome dose-related artifacts, such as radiolysis and electrostatic charging, is challenging due to the inherently low contrast in imaging of many such materials. These challenges are particularly exacerbated during dynamic time-resolved, fluidic cell imaging, or three-dimensional tomographic reconstruction—all of which undergo additional dosage. Thus, there is a pressing need for the development of techniques to produce high-quality images at ever lower electron doses. In this contribution, we demonstrate direct dose reduction and suppression of beam-induced artifacts through under-sampling pixels, by as much as 80% reduction in dosage, using a commercial scanning electron microscope with an electrostatic beam blanker and a dictionary learning in-painting algorithm. This allows for multiple sparse recoverable images to be acquired at the cost of one fully sampled image. We believe this approach may open new ways to conduct imaging, which otherwise require compromising beam current and/or exposure conditions.

CT scanning technology is a valuable tool to diagnose many diseases; however, the levelof the radiation dose is a source of concern, especially for children. CT scan systems anddose measurement methods have evolved over the years; but reported pediatric effectivedoses (EDs) have sometimes exceeded the annual dose limit recommended by the ICRP (1 mSvper year for persons under 18 years) (ICRP, 2007a).Efforts have been made to reduce organ doses and EDs by adjusting the scan parameters.This paper describes the determinants of the ED, and the dose reduction techniques inpediatric imaging from the early age of CT examinations until now. The firstepidemiological results regarding the associated risk of cancer are also brieflypresented.

Objectives: To explore the cost-effectiveness of early biologic treatment, followed by dose-reduction in the case of remission, of active rheumatoid arthritis (RA), compared with standard treatment with methotrexate (MTX) in Sweden.

Methods: Effectiveness (function, disease activity, erosions) in early RA for both alternatives was taken from a clinical trial comparing etanercept (ETA) combined with MTX to MTX alone. Patients discontinuing treatment can switch to another or their first biologic treatment. For patients in remission (Disease Activity Score [DAS28] < 2.6), ETA is reduced to half the dose. Return to full dose occurs when DAS28 reaches ≥ 3.2 again. Costs and utilities by level of functional capacity from an observational study are used. The model is analyzed as a micro-simulation and results are presented from the societal perspective for Sweden, for 10 years; costs (€2008) and effects are discounted at 3 percent. Sensitivity analysis was performed for the perspective, the time horizon, switching, and dose-reduction.

Results: The main analysis conservatively assumes 50 percent switching at discontinuation. The cost per quality-adjusted life-year (QALY) gained with early ETA/MTX treatment is €13,500 (societal perspective, incremental cost of €15,500 and incremental QALYs of 1.15). With 75 percent switching, the cost per QALY gained was €10,400. Over 20 years, the cost per QALY gained was €8,200. Results were further sensitive to the time patients remained on half dose and the perspective.

Conclusions and Policy Implications: This study combines clinical trial and clinical practice data to explore cost-effective treatment scenarios in early RA, including the use of biologics. Our results indicate that a situation where a considerable proportion of patients achieve remission, dose-adjustments will increase the cost-effectiveness of treatment.