Ultraschall Emissionen: Thermische (TI) und mechanische (MI) Indizes

Abstract

Link to publication Citation for published version (APA): Kollmann, C., ter Haar, G., Dolezal, L., Hennerici, M., Salvesen, K. A., & Valentin, L. (2013). Ultrasound Output: Thermal (TI) and Mechanical (MI) Indices. Ultraschall in der Medizin, 34(5), 422-434. DOI: 10.1055/s-0033-1335843 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Affiliations:Authors: Key words:Ultrasound, output, safety, thermal index, mechanical index Educational objectives-to know the general exposure concept and its application -to recognise the concept´s limitations and drawbacks -to get to know related safety implications -to be familiar with TI/MI limits that require user action during scanning Ultrasound output: Thermal (TI) and Mechanical (MI) IndicesBasic Terminology ALARA -As Low As Reasonable Achievablea principle that should be followed whenever possible. The aim is use the lowest machine settings that are compatible with obtaining the required diagnostic information during an ultrasound investigation, and thus to reduce the patient´s exposure to ultrasound. FDA -U.S. Food and Drug AdministrationAmerican agency that is responsible for protecting public health by assuring the safety, efficacy and security of human and veterinary drugs, biological products, medical devices, the nation's food supply, cosmetics, and products that emit radiation. MI -Mechanical Index -a unitless parameter that is calculated online to give a rough estimate of the risk, from mechanical causes, associated with the ultrasound beam. This is dependent on the actual settings of the device and is indicative of non-thermal bio-effects. ODS -Output Display Standard -an American Standard that describes the calculation and display of TI and MI. TI -Thermal Index -a unitless parameter that is calculated online to give a rough estimate of the risk, from thermal causes, associated with the ultrasound beam. This is dependent on the actual settings of the device and is indicative for the potential for temperature rise. A higher TI meaning that the temperature rise might be higher than with a lower TI. Depending on the tissue path involved for the application there are 3 different indices defined:TIS -Thermal Index for soft tissue TIB -Thermal Index with bone near the focus TIC -Thermal Index for cranial applications

Ultrasound-mediated microbubbles cavitation enhanced chemotherapy of advanced prostate cancer by increasing the permeability of blood-prostate barrier

“…Thermal effect is another important effect induced by ultrasound, and previous literature has reported that elevated temperature can induce tumor death or apoptosis [35] . Thermal effect is related to the intensity of ultrasound and the Thermischer Index (TI) [36] . In this study, the acoustic power of the US instrument was less than 720 mW/cm 2 and TI was approximately 0.1.…”

Ultrasound‐controlled drug release and drug activation for cancer therapy

“…To this end, the FDA has formulated two criteria to quantify the tissue effects induced by US, namely thermal index (TI) and mechanical index (MI). [ 135 ] The former represents the energy required to raise the tissue temperature by 1 °C, while the latter refers to a combination of ultrasonic parameters such as frequency and amplitude. On these grounds, current efforts should focus on the widespread use of US with high frequency, low amplitude, short irradiation time, and few duty cycles to achieve drug release and drug activity safely.…”

Therapeutic Assessment of High-Intensity Focused Ultrasound for Vulvar Lichen Sclerosus by Active Dynamic Thermal Imaging and Hyperspectral Imaging—A Preliminary Study

“…A lower MI indicates a lower degree of cavitation effect. A value lower than 0.5 is considered to indicate no bubble growth [37,38], whereas 1.9 is considered to be the maximal threshold of no bioeffects, which is a value that is also adopted by the Food and Drug administration in its regulation for diagnostic ultrasound [37]. In regular HIFU treatment for cancers, which utilizes a high intensity of ultrasound, the cavitation effect plays an important role in curing lesions.…”