HITU FIELD CHARACTERIZATION USING TISSUE MIMICKING MATERIAL
Saletta Conferenze, edificio M, piano interrato
I dispositivi a ultrasuoni terapeutici ad alta intensità (HITU) possono essere sottoposti a diversi test preclinici. Per quello che riguarda la misurazione e lo sviluppo di modelli, molti metodi possono essere utilizzati. Uno di questi prevede di utilizzare materiali in grado di simulare il comportamento dei tessuti biologici (tissue-mimicking material, TMM). La relatrice illustrerà i risultati di uno studio comparativo tra simulazioni e misurazioni della distribuzione del campo acustico HITU in acqua e TMM e dell’aumento della temperatura in TMM.
Dott.ssa Subha Maruvada
FDA - Food and Drug Administration
For high intensity therapeutic ultrasound (HITU) devices, pre-clinical testing can include measurement of power, pressure/intensity and temperature distribution, acoustic and thermal simulations, and assessment of targeting accuracy and treatment monitoring. Though relevant standards are available, technical challenges remain because of the often focused, large amplitude pressure fields encountered. Measurement and modeling issues include using hydrophones and radiation force balances at HITU power levels, validation of simulation models, and a suitable tissue-mimicking material (TMM) for pre-clinical bench testing. To better understand these issues, a comparison study was undertaken between simulations and measurements of the HITU acoustic field distribution in water and TMM, and temperature rise in TMM. For the specific conditions of this study, the following results were obtained. In water, the simulated values for p+ and p- were 3% lower and 10% higher, respectively, than those measured by hydrophone. In TMM, the simulated values for p+ and p- were 2% and 10% higher than those measured by hydrophone, respectively. The simulated spatial-peak temporal-average intensity values in water and TMM were greater than those obtained by hydrophone by 3%. Simulated and measured end-of-sonication temperatures agreed to within their respective uncertainties (coefficients of variation of approximately 20% and 10%, respectively).
Subha Maruvada is the lead for the Therapeutic Ultrasound Program in the Division of Applied Mechanics which is a part of the Office of Science and Engineering Laboratories. With a background in Electrical and Acoustical Engineering and Acoustics, Dr. Maruvada has worked in the area of acoustics measurements and modeling for over 20 years.