Notes

Myopic loss aversion or perhaps equate-to-differentiate heuristic? A new heuristic decisions style for both single and also aggregated takes on.
High-frame-rate volume imaging (HFR-VI) aims to provide high-quality images with high-temporal information. Despite its potential, HFR-VI translation into clinical applications has been challenging due to the high cost of the equipment required to drive matrix probes with a large number of elements. The goal of this study is to introduce and test sparse-random-aperture compounding (SRAC), a technique that allows use of matrix probes with an ultrasound system that has fewer channels while maintaining high frame rates. Four scanning methods were implemented with a 256-channel system using a 4-to-1 multiplexer and a 3-MHz matrix probe with 1024 elements. These methods used three types of waves, either single-diverging waves (SDW), multiplane-diverging waves (MDW) or wide beams (WB); and were driven using one to four SRAC. All methods were also implemented in a 1024-channel multisystem. The main-lobe-to-side-lobe ratio (MLSLR) and the contrast ratio (CR) were studied using a string phantom and a CIRS phantom, respectively. The results showed an increase in the MLSLR and CR as a function of the number of SRAC. The multisystem provided the best results for the MLSLR. However, four SRAC outperformed the multisystem with respect to CR. The method using SDW provided the highest frame rates (i.e., 1875 and 7500 Hz for four and one SRAC, respectively), however it provided the lowest image quality. The two methods using MDWs showed a good compromise between image quality and frame rate (i.e., 187 to 750 Hz for four and one SRAC). WB provided the best image quality at the expense of frame rate (i.e., 18 to 75 Hz for four and one SRAC). Our results suggest that SRAC in combination with the tested scanning methods can provide a low-channel count alternative for HFR-VI systems and allows a tunable tradeoff between image quality and frame rate guided by the desired application.Objectives To analyze the association between dose-volume relationships and adverse effects in brainstem lesions treated with Gamma Knife radiosurgery (GKRS). Methods Treatment plans were generated on BrainLab Elements and GammaPlan software. Dosimetric data were analyzed as continuous variables for patients who received GKRS to brain metastases or arteriovenous malformations (AVM) within or abutting the brainstem. Adverse effects were classified as clinical and/or radiographic. Logistic and cox regression were used to assess the relationship between dosimetric variables and adverse effects. Results Sixty-one patients who underwent single fraction GKRS for brain metastases or AVM were retrospectively analyzed. Median age was 62 years (range 12-92 years) and median prescription dose was 18 Gy (range 13-25 Gy). Median follow-up was 6 months. Clinical and radiographic complications were seen in ten (16.4%) and 17 (27.9%) of patients, respectively. On logistic regression, D05% was found to be associated with an increased probability of developing a clinical complication post-GKRS (OR 1.18; 95% CI 1.01-1.39; p=0.04). Furthermore, mean brainstem dose (HR 1.43; 95% CI 1.05-1.94; p less then 0.02), D05% (HR 1.09; 95% CI 1.01-1.18; p=0.03), and D95% (HR 2.37; 95% CI 0.99-5.67; p=0.05) were associated with an increased hazard of experiencing post-GKRS over time. Conclusions Increasing D05% to the brainstem is associated with an increased risk of developing clinical complications. Clinicians may consider this parameter in addition to fractionated stereotactic radiation therapy when well-established dose constraints are not met in this patient population. Additional data are needed to further validate these findings.Right anterior minithoracotomy is gaining larger acceptance for isolated aortic valve replacement. In some patients however, surgical exposure during the intervention may be challenging even for experienced surgeons or centers. see more In our opinion, a proper preoperative selection of the patients by a CT-scan seems mandatory. We routinely perform right anterior minithoracotomy and over time we have found that the angle between the right border of the sternum and the left side of the aorta, at the level of the pulmonary artery, helps with patients' selection.Purpose Custom-fabricated lead shields are often used for superficial radiation treatments to reduce radiation doses to adjacent healthy tissue. However, the process for fabricating these lead shields is time-consuming, labor-intensive, and uncomfortable for patients. Alternatively, patient-specific shields can be 3D-printed from a high-density bronze-based filament to address these concerns. This study was performed to assess the shielding characteristics of 3D-printed bronze (3DPB) shields, demonstrate their clinical viability, and report the first ever published case of a patient treated with a 3DPB shield. Methods and materials The transmission of 6 and 9 MeV electron beams through varying thicknesses of 3DPB was first measured. Percent depth doses (PDD) and beam profiles were measured with flat 3DPB shields and equivalent lead shields to determine surface dose enhancement, output factors, and field widths. Two 3DPB shields were designed and fabricated for an anthropomorphic phantom, and phantom measurements were performed using optically stimulated luminescence dosimeters (OSLD) and film. Finally, 3DPB shields have been used during the treatment of seven patients' skin lesions. Results 10 and 15 mm of 3DPB were sufficient to shield 6 and 9 MeV electrons by 95%, respectively. The 3DPB and lead shields had nearly identical beam widths (within 1%). Output factors were on average within 0.8% for bronze shields and 1.2% for lead shields relative to an unshielded field. The skin enhancement for bronze was higher than for lead by an average of 6.3%. Phantom measurements using 3DPB shields generally showed less than 3% transmission of the primary beam under the 3DPB shield. The patients' shields fit as designed and were all deemed clinically acceptable by their physicians. Conclusions The 3DPB shields fit better than lead shields, are easier to design and manufacture, and have similar dosimetric properties. 3DPB shields are a viable clinical option for patient-specific superficial shielding.
Read More: https://www.selleckchem.com/products/pco371.html