Design and Development of Single Element Focused Ultrasound Transducers

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dc.contributor.authorDodoo, Neffisah Fadillah Naa Darkuaen
dc.contributor.committeechairVlaisavljevich, Elien
dc.contributor.committeememberMaxwell, Adamen
dc.contributor.committeememberShahab, Shimaen
dc.contributor.departmentDepartment of Biomedical Engineering and Mechanicsen
dc.date.accessioned2024-06-12T08:01:28Zen
dc.date.available2024-06-12T08:01:28Zen
dc.date.issued2024-06-11en
dc.description.abstractHistotripsy is a non-invasive, non-thermal, and non-ionizing therapy that utilizes converging high-pressure ultrasound waves at a focal point to produce cavitation and induce mechanical tissue destruction. Currently, rapid prototyped histotripsy transducers consist of multiple elements and are made using 3D printing methods. Multi-element transducers introduce size constraints and 3D printing has limitations in material choice, cost, and time for larger scale manufacturing. This thesis investigates the development of rapid prototyped single element histotripsy transducers and the use of injection molding for transducer fabrication, utilizing an in-house metal CNC mill for mold manufacturing and a desktop injection molding machine. Nylon 101 and 30% glass-filled nylon were chosen as the plastics to inject as these were found to have the most similar acoustic properties to WaterShed, an ABS-like plastic currently used. Six single-element transducers were constructed with a 2 MHz curved Pz26 piezoceramic disc: two with SLA 3D printed housing, two with SLS 3D printed housing, and two with injection molded housing. Electrical impedance, beam dimensions, focal pressure output, and cavitation were characterized for each element. The results show that rapid prototyped single element transducers can generate enough pressure to perform histotripsy. This marks the development of the first rapid prototyped single element histotripsy transducer and further confirms that injection molding can produce transducers comparable, if not identical or potentially superior, to 3D printed counterparts. Future work aims to further characterize these transducers, explore more material options, and apply injection molding to various transducer designs while optimizing both CNC and injection molding parameters.en
dc.description.abstractgeneralHistotripsy is a form of cancer therapy that can non-invasively treat tumors using focused ultrasound waves. Focused ultrasound transducers are used to achieve this and are currently prototyped using 3D printing. However, these methods are limiting in material options and upscale manufacturing. Many of these devices currently used tend to be larger in size, comparable to the size of a mixing bowl, which limits its applications. This thesis investigates the development of single element histotripsy transducers and the use of injection molding for transducer fabrication, using an in-house metal CNC mill for mold manufacturing and desktop injection molding machine. Nylon 101 and 30% glass-filled nylon were chosen as the plastics to inject due to their ideal acoustic properties. Six single-element transducers were constructed: two with SLA 3D printing, two with SLS 3D printing, and two with injection molding. All transducers were tested and compared against each other. The results show that 3D printed single element transducers can perform histotripsy and that injection molding can produce comparable results. Future work should continue to test and characterize these transducers, explore more material options for injection molding, apply injection molding to other transducer designs, and optimize CNC and injection molding parameters.en
dc.description.degreeMaster of Scienceen
dc.format.mediumETDen
dc.identifier.othervt_gsexam:40712en
dc.identifier.urihttps://hdl.handle.net/10919/119401en
dc.language.isoenen
dc.publisherVirginia Techen
dc.rightsCreative Commons Attribution-ShareAlike 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by-sa/4.0/en
dc.subjectfocused ultrasounden
dc.subjecthistotripsyen
dc.subjectprototypingen
dc.subject3D printingen
dc.subjectinjection moldingen
dc.subjecttransduceren
dc.titleDesign and Development of Single Element Focused Ultrasound Transducersen
dc.typeThesisen
thesis.degree.disciplineBiomedical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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