Measuring local RF heating in MRI: Simulating perfusion in a perfusionless phantom

Purpose: To overcome conflicting methods of local RF heating measurements by proposing a simple technique for predicting in vivo temperature rise by using a gel phantom experiment. Materials and Methods: In vivo temperature measurements are difficult to conduct reproducibly; fluid phantoms introduce convection, and gel phantom lacks perfusion. In the proposed method the local temperature rise is measured in a gel phantom at a timepoint that the phantom temperature would be equal to the perfused body steady-state temperature value. The idea comes from the fact that the steady-state temperature rise in a perfused body is smaller than the steady-state temperature increase in a perfusionless phantom. Therefore, when measuring the temperature on a phantom there will be the timepoint that corresponds to the perfusion time constant of the body part. Results: The proposed method was tested with several phantom and in vivo experiments. Instead, an overall average of 30.8% error can be given as the amount of underestimation with the proposed method. This error is within the variability of in vivo experiments (45%). Conclusion: With the aid of this reliable temperature rise prediction the amount of power delivered by the scanner can be controlled, enabling safe MRI examinations of patients with implants. © 2007 Wiley-Liss, Inc

Activity of venetoclax in patients with relapsed or refractory chronic lymphocytic leukaemia: analysis of the VENICE-1 multicentre, open-label, single-arm, phase 3b trial

Background: Most patients with chronic lymphocytic leukaemia progress after treatment or retreatment with targeted therapy or chemoimmunotherapy and have limited subsequent treatment options. Response levels to the single-agent venetoclax in the relapsed setting is unknown. We aimed to assess venetoclax activity in patients with or without previous B-cell receptor-associated kinase inhibitor (BCRi) treatment. Methods: This multicentre, open-label, single-arm, phase 3b trial (VENICE-1) assessed activity and safety of venetoclax monotherapy in adults with relapsed or refractory chronic lymphocytic leukaemia, stratified by previous exposure to a BCRi. Eligible participants were aged 18 years or older with previously treated relapsed or refractory chronic lymphocytic leukaemia. Presence of del(17p) or TP53 aberrations and previous BCRi treatment were permitted. Patients received 5-week ramp-up to 400 mg of oral venetoclax once daily and were treated for up to 108 weeks, with 2 years follow-up after discontinuation, or optional extended access. The primary activity endpoint was complete remission rate (complete remission or complete remission with incomplete marrow recovery) in BCRi-naive patients. Analyses used the intent-to-treat (ie, all enrolled patients, which coincided with those who received at least one dose of venetoclax). This study was registered with ClinicalTrials.gov, NCT02756611, and is complete. Findings: Between June 22, 2016, and March 11, 2022, we enrolled 258 patients with relapsed or refractory chronic lymphocytic leukaemia (180 [70%] were male; 252 [98%] were White; 191 were BCRi-naive and 67 were BCRi-pretreated). Median follow-up in the overall cohort was 49·5 months (IQR 47·2–54·1), 49·2 months (47·2–53·2) in the BCRi-naive group, and 49·7 months (47·4–54·3) in the BCRi-pretreated group. Of 191 BCRi-naive patients, 66 (35%; 95% CI 27·8−41·8) had complete remission or complete remission with incomplete marrow recovery. 18 (27%; 95% CI 16·8–39·1) of 67 patients in the BCRi-pretreated group had complete remission or complete remission with incomplete marrow recovery. Grade 3 or worse treatment-emergent adverse events were reported in 203 (79%) and serious adverse events were reported in 136 (53%) of 258 patients in the overall cohort. The most common treatment-emergent adverse event was neutropenia (96 [37%]) and the most common and serious adverse event was pneumonia (21 [8%]). There were 13 (5%) deaths reported due to adverse events; one of these deaths (autoimmune haemolytic anaemia) was possibly related to venetoclax. No new safety signals were identified. Interpretation: These data demonstrate deep and durable responses with venetoclax monotherapy in patients with relapsed or refractory chronic lymphocytic leukaemia, including BCRi-pretreated patients, suggesting that venetoclax monotherapy is an effective strategy for treating BCRi-naive and BCRi-pretreated patients. Funding: AbbVie

Design and implementation of a low-cost high-performance syringe pump system

21st National Biomedical Engineering Meeting, BIYOMUT 2017 -- 24 November 2017 through 26 November 2017 -- -- 140363This study describes design and implementation of a high- performance, low-cost, syringe pump device. Proposed device can be used with different injectors having volumes that are ranging from a common 0.5 mL to a larger 60 mL. This adaptable and programmable syringe pump provides high accuracy and adjustable flow rate in a simple mechanical manner and costs approximately $200. Developed system was tested on an optical table in lab conditions. It is measured that system can provide rates up to 0.05 mL/h, when used on a 0.5 mL syringe whereas the maximum volume 60 mL injector can provide a flow rate of 5.8 mL/h. Mean flow rate error of the system is calculated as 1.33%. Time-distance plots reveal a high degree of linearity and negligible hysteresis. Thus, the manufactured syringe pump is an excellent candidate as a high-precision liquid delivery system for low-resource settings. © 2017 IEEE

Two-wavelength grating interferometry for extended range MEMS metrology

Diffraction gratings integrated with MEMS has many applications as they can offer shot noise limited sub-nm displacement detection sensitivities but are limited in range. A two-wavelength readout method is developed that maintains high sensitivity while increasing the detection range from 105nm to 1.7um assuming sensitivity is maintained at > 50% of the maximum sensitivity.IM

A 3D Polymer Based Printed Two-Dimensional Laser Scanner

27th Micromechanics and Microsystems Europe (MME) Workshop -- AUG 28-30, 2016 -- Cork, IRELANDA two-dimensional (2D) polymer based scanning mirror with magnetic actuation is developed for imaging applications. Proposed device consists of a circular suspension holding a rectangular mirror and can generate a 2D scan pattern. Three dimensional (3D) printing technology which is used for implementation of the device, offers added flexibility in controlling the cross-sectional profile as well as the stress distribution compared to the traditional planar process technologies. The mirror device is developed to meet a portable, miniaturized confocal microscope application in mind, delivering 4.5 and 4.8 degrees of optical scan angles at 111 and 267 Hz, respectively. As a result of this mechanical performance, the resulting microscope incorporating the mirror is estimated to accomplish a field of view (FOV) of 350 mu m x 350 mu m