Looking Forward with Minimally Invasive Ultrasound

Minimally invasive procedures are increasingly replacing traditional open surgeries due to their shorter recovery time, reduced patient pain, reduced risk of infection and less trauma. However, since the physician has no direct view of the working field, visualization of these complex interventions is critical for success. Forward-looking (FL) ultrasound image guidance can aid minimally invasive procedures providing visual feedback of the working field, instrument location and treatment progress. Currently there are no clinically available devices that can provide minimally invasive 3D FL imaging. In this thesis we explored several innovative solutions towards miniaturized 3D FL imaging. We looked into methods to solve both hardware and image-related challenges resulting in mainly two approaches. The first approach consists in the realization of a complex multi-element transducer with an optimized design and an efficient interconnection and integration scheme. The second approach consists in the use of s

Structured ultrasound microscopy

We present a form of acoustic microscopy, called Structured Ultrasound Microscopy (SUM). It creates a volumetric image by recording reflected echoes of ultrasound waves with a structured phase front using a moving single-element transducer and co

Preparation of cellulosic fibers with biological activity by immobilization of trypsin on periodate oxidized viscose fibers

In this study, a biologically active fibrous material was designed by immobilizing trypsin on viscose fibers. The viscose yarn was first oxidized with sodium periodate to produce aldehyde groups and then employed as a support for subsequent immobilization of trypsin through bovine serum albumin. The oxidation by sodium periodate caused changes in the chemical and physical properties of the modified yarn samples, which were evaluated by determining the aldehyde group content, fineness and tensile strength of yarn. The viscose fibers oxidized under the most severe conditions (0.4 % NaIO4, 360 min) exhibited the maximum amount of introduced aldehyde groups (1.284 mmol/g), but also the highest decrease in tensile strength. The trypsin activity was assayed with N-alpha-benzoyl-DL-arginine p-nitroanilide hydrochloride, whereas the amount of bound trypsin was determined by Bradford method. Trypsin immobilized on oxidized viscose yarn retained 97.3 and 83.8 % of the initial activity over 60 days of storage at 4 and 25 A degrees C, respectively, and remained firmly attached to the carrier. The potential application of obtained bioactive fibers is in the treatment of wounds