A steepest-descent gradient algorithm is developed to optimize the stepping of a 90Sr/90Y radiation source train (RST) for intravascular brachytherapy (IVB). The objective function is to deliver a uniform dose in a coronary target vessel and minimize the dose in adjacent normal vessel tissue at the proximal and distal edges of the coronary target vessel. Based on the target length and number of dwell points (number of steps), the algorithm modulates the dwell times and corresponding dwell positions that optimize the weighted addition of staggered EGS4 Monte Carlo (MC) calculated dose distribution from a single RST. Stepping treatment plans are generated for target vessel lengths of 3.0, 3.3, and 3.8 cm. For both the unoptimized and optimized plans, the dose heterogeneity in the target vessel wall, and length of nontarget vessel receiving 3 Gy, is assessed to compare plans. Optimization results show a 14% dose uniformity within the target is achievable for all vessel lengths. Further, the dose in the adjacent normal tissue is lower in the optimized plans than the unoptimized plans. The work presented in this paper provides a model to address the finite length of RST in IVB treatments. While the results presented are specific to the 90Sr/90Y RST, the methods should apply to other finite length RSTs.
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http://dx.doi.org/10.1118/1.1524169 | DOI Listing |
J Endovasc Ther
January 2025
Angiology, HFR Fribourg, Hôpital Universitaire et Cantonal, Fribourg, Switzerland.
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January 2025
Department of Electrical Engineering, Columbia University, New York, New York, USA.
Epicardial catheter ablation is necessary to address ventricular tachycardia targets located far from the endocardium, but epicardial adipose tissue and coronary blood vessels can complicate ablation. We demonstrate that catheter-based near-infrared spectroscopy (NIRS) can identify these obstacles to guide ablation. Eighteen human ventricles were mapped ex vivo using NIRS catheters with optical source-detector separations (SDSs) of 0.
View Article and Find Full Text PDFCureus
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Research, Clarity Science LLC, Narragansett, USA.
The recent identification of Piezo ion channels demonstrating a mechano-sensitive impact on neurons revealed distinct Piezo-1 and 2 types. While Piezo-1 predominates in neurons linked to non-sensory stimulation, such as pressure in blood vessels, Piezo-2 predominates in neurons linked to sensory stimulation, such as touch. Piezo-1 and 2 have a major bidirectional impact on transient receptor potential (TRP) ion channels, and TRPs also impact neurotransmitter release.
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Department of Internal Medicine, Division of Cardiology, Iwate Medical University, 2-1-1 Idaidori, Yahaba-Cho, Shiwa-Gun, Iwate, 028-3695, Japan.
In clinical practice, the impact of procedural or patient-related risk factors on 1-year clinical outcomes in patients receiving 1-month of dual antiplatelet therapy (DAPT) followed by P2Y12 inhibitor monotherapy after contemporary percutaneous coronary intervention (PCI) remains unclear. Using data from the multi-center REIWA registry which included patients treated with thin-strut biodegradable polymer drug-eluting stent (BP-DES) and 1-month DAPT followed by P2Y12 inhibitor monotherapy, we assessed the primary endpoint (a composite of cardiovascular death, myocardial infarction, definite stent thrombosis, ischemic or hemorrhagic stroke, and major or minor bleeding) in patients with and without procedural (treatment of three vessels, three or more lesions, three or more stents, bifurcation with two stents, long stenting, and target of chronic total occlusion) and patient-related risk factor (renal insufficiency, anemia, peripheral vascular disease, prior or current history of heart failure and advanced age of ≥ 75 years). Among the 1,202 patients who underwent complete revascularization by PCI, 276 (23.
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Department of Geriatrics, Medical Center on Aging of Shanghai Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
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