Dosimetric outcomes of preoperative treatment planning with intraoperative optimization using stranded seeds in prostate brachytherapy.

This study aimed to evaluate the quality of low-dose-rate (LDR) prostate brachytherapy (BT) based on treatment-related dosimetric outcomes. Data of 100 patients treated using LDR BT with stranded seeds from November 2012 to November 2017 were collected. The prescription dose for the prostate was 145 Gy.

Microstructured Surfaces for Reducing Chances of Fomite Transmission via Virus-Containing Respiratory Droplets.

Evaporation-induced particle aggregation in drying droplets is of significant importance in the prevention of pathogen transfer due to the possibility of indirect fomite transmission of the infectious virus particles. In this study, particle aggregation was directionally controlled using contact line dynamics (pinned or slipping) and geometrical gradients on microstructured surfaces by the systematic investigation of the evaporation process on sessile droplets and sprayed microdroplets laden with virus-simulant nanoparticles. Using this mechanism, we designed robust particle capture surfaces by significantly inhibiting the contact transfer of particles from fomite surfaces.

Detailed evaluation of Mobius3D dose calculation accuracy for volumetric-modulated arc therapy.

Purpose: To perform a detailed evaluation of dose calculation accuracy and clinical feasibility of Mobius3D. Of particular importance, multileaf collimator (MLC) modeling accuracy in the Mobius3D dose calculation algorithm was investigated.

Methods: Mobius3D was fully commissioned by following the vendor-suggested procedures, including dosimetric leaf gap (DLG) optimization.

Clinical Evaluation of Commercial Atlas-Based Auto-Segmentation in the Head and Neck Region.

While atlas segmentation (AS) has proven to be a time-saving and promising method for radiation therapy contouring, optimal methods for its use have not been well-established. Therefore, we investigated the relationship between the size of the atlas patient population and the atlas segmentation auto contouring (AC) performance. A total of 110 patients' head planning CT images were selected.

Imaging heterogeneous nanostructures with a plasmonic resonant ridge aperture.

We introduce a plasmonic resonance ridge aperture capable of sensing changes in refractive index and absorption with nanoscale resolution. Using this aperture, we devised a plasmonic near-field scanning nanoscope (PNSN) to record images of heterogeneous nanostructures. Compared to a conventional near-field scanning optical microscope (NSOM) that measures light scattered by the sample, the PNSN directly measures the change in a beam reflected from the aperture to detect buried objects.

Plasmonic nano lithography with a high scan speed contact probe.

We demonstrate plasmonic lithography with an optical contact probe to achieve high speed patterning without external gap distance control between the probe and the photoresist. The bottom surface of the probe is covered with a 10 nm thickness silica glass film for the gap distance control and coated with self-assembled monolayer (SAM) to reduce friction between the probe and the photoresist. We achieve a patterning resolution of ~50 nm and a patterning speed of ~10 mm/s.

Modeling of three-dimensional photoresist profiles exposed by localized fields of high-transmission nano-apertures.

Using a simple theoretical model, we calculate three-dimensional profiles of photoresist exposed by arbitrarily shaped localized fields of high-transmission metal nano-apertures. We apply the finite difference time domain (FDTD) method to obtain the localized field distributions, which are generated by excitation of localized surface plasmon polaritons underneath a C-shaped or a bow-tie-shaped aperture. Incorporating the results of FDTD simulations with the theoretical model, we visualize three-dimensional exposure profiles of the photoresist as a function of the exposure dose and the gap distance between the aperture and the photoresist.