Vascular damage is one of the therapeutic mechanisms of photodynamic therapy (PDT). In particular, short-term PDT treatments can effectively destroy malignant lesions while minimizing damage to nonmalignant tissue. In this study, we investigate the feasibility of label-free quantitative photoacoustic microscopy (PAM) for monitoring the vasculature changes under the effect of PDT in mouse ear melanoma tumors. In particular, quantitative vasculature evaluation was conducted based on Hessian filter segmentation. Three-dimensional morphological PAM and depth-resolved images before and after PDT treatment were acquired. In addition, five quantitative vasculature parameters, including the PA signal, vessel diameter, vessel density, perfused vessel density, and vessel complexity, were analyzed to evaluate the influence of PDT on four different areas: Two melanoma tumors, and control and normal vessel areas. The quantitative and qualitative results successfully demonstrated the potential of the proposed PAM-based quantitative approach to evaluate the effectiveness of the PDT method.

Correct guiding of the catheter is a critical issue in almost all balloon catheter applications, including arterial stenosis expansion, coronary arterial diseases, and gastrointestinal tracking. To achieve safe and precise guiding of the balloon catheter, a novel imaging method with high-resolution, sufficient depth of penetration, and real-time display is required. Here, we present a new balloon catheter guiding method using fast photoacoustic microscopy (PAM) technique for precise balloon catheter tracking and visualization as a feasibility study. We implemented ex vivo and in vivo experiments with three different medium conditions of balloon catheter: no air, air, and water. Acquired cross-sectional, maximum amplitude projection (MAP), and volumetric 3D PAM images demonstrated its capability as a new imaging guiding tool for balloon catheter tracking and visualization.

Carfilzomib is mainly used to treat multiple myeloma. Several side effects have been reported in patients treated with carfilzomib, especially those associated with cardiovascular events, such as hypertension, congestive heart failure, and coronary artery disease. However, the side effects, especially the manifestation of cardiovascular events through capillaries, have not been fully investigated. Here, we performed a pilot experiment to monitor peripheral vascular dynamics in a mouse ear under the effects of carfilzomib using a quantitative photoacoustic vascular evaluation method. Before and after injecting the carfilzomib, bortezomib, and PBS solutions, we acquired high-resolution three-dimensional PAM data of the peripheral vasculature of the mouse ear during each experiment for 10 h. Then, the PAM maximum amplitude projection (MAP) images and five quantitative vascular parameters, i.e., photoacoustic (PA) signal, diameter, density, length fraction, and fractal dimension, were estimated. Quantitative results showed that carfilzomib induces a strong effect on the peripheral vascular system through a significant increase in all vascular parameters up to 50%, especially during the first 30 min after injection. Meanwhile, bortezomib and PBS do not have much impact on the peripheral vascular system. This pilot study verified PAM as a comprehensive method to investigate peripheral vasculature, along with the effects of carfilzomib. Therefore, we expect that PAM may be useful to predict cardiovascular events caused by carfilzomib.

Background: This study was designed as a dosimetric feasibility analysis to compare hippocampal-avoidance whole-brain radiotherapy (HA-WBRT) using 3D-CRT, IMRT, and VMAT techniques, with particular attention to clinical applicability in resource-limited settings. While 3D-CRT was used as a reference for conventional WBRT, the primary aim was to determine whether IMRT can serve as an effective and accessible alternative to VMAT for HA-WBRT in centers without advanced technology infrastructure. Methods: Fifteen patients undergoing WBRT for symptom relief were planned using 3D-CRT, IMRT, and VMAT on the Elekta Monaco 6.1.4.0 system. Key organs at risk (OARs) such as the optic nerves, chiasm, eyes, and lenses were considered in the treatment planning. Plans were evaluated based on PTV dose distribution, Conformity Index (CI), Homogeneity Index (HI), and OAR dose constraints (RTOG 0933, NRG-CC001). Gamma pass rate analysis (3%/3 mm) was performed for the IMRT and VMAT plans. Results: IMRT and VMAT significantly reduced the hippocampal dose compared to 3D-CRT, with similar PTV coverage and OAR sparing. The mean D_max for the hippocampus was 15.4 Gy for IMRT and 15.5 Gy for VMAT compared to 31.2 Gy for 3D-CRT. The D100% for the hippocampus was 7.5 Gy for IMRT and 7.6 Gy for VMAT, both well below the RTOG 0933 threshold of 9 Gy, while 3D-CRT delivered 30.3 Gy. Additionally, IMRT and VMAT delivered lower doses to the optic nerves and chiasm. QA results showed gamma pass rates above 96% for all plans. This study focused solely on treatment-planning and dosimetric feasibility without evaluating patient outcomes or clinical follow-up. Conclusions: HA-WBRT with IMRT and VMAT significantly reduced the hippocampal dose while maintaining optimal PTV coverage. VMAT is preferred for its balance of efficacy, protection, and treatment time, while IMRT represents a feasible approach for facilities without VMAT, though it requires stricter dose control and longer treatment times.