Temperature measurements under ultrasound exposure: e-learning course

This course will cover the fundamentals of temperature measurements under ultrasound exposures. The course is addressed to medical physics researchers, students, industry and clinicians working in medical ultrasound. The course is composed of 12 lectures divided in 4 modules. The lectures are provided by international experts in the field, coming from academia, clinics and metrology.

The videos have an average duration of 8 minutes. Although the whole course will provide a wide overview of the topic, the videos are independent and can be watched separately. At the end of each module there is a questionnaire which covers the most relevant aspects discussed in the videos.

The first module is introductory and discusses the general questions on why it is important to have an understanding of temperature increase during ultrasound exposure, and the main technical challenges to measure the temperature.

The second module covers the background with discussions about the regulatory framework, the exploitation of temperature increases in clinics and the role of simulations.

The third module covers laboratory measurements, using tissue mimicking materials as phantom components and as temperature sensors themselves. The
use of thermocouples and infrared camera, the two most common methods to measure temperature under ultrasound exposure.

The forth and last module introduces the two methods currently employed to measure temperature increase in clinics under ultrasound exposure, namely
magnetic resonance thermometry and ultrasound thermography.

The course was developed in the framework of the EURAMET EMPIR 18HLT06 RaCHy Project: Radiotherapy coupled with hyperthermia. This project has
received funding from the EMPIR programme co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation

Enjoy the view and feel free to contact the owners or the authors for comments or questions.

Module 1

- Take the Module 1 Questionnaire

In this module the problem of measuring temperature under ultrasound exposure is presented. Dr. Piero Miloro from the National Physical Laboratory (UK) will introduce the topic of why temperature increases in tissues when exposed to ultrasound waves and why is it important to quantify the temperature. Professor Gail ter Haar from the Institute of Cancer Research will talk about the effects ultrasound has on biological tissues, of which temperature is one of the most relevant. These effects can be beneficial or dangerous depending on the intended scope. Finally, Dr Piero Miloro will give an overview of the current methods to measure temperature increase, with their advantages and drawbacks.

Why we need temperature measurements – Author Piero Miloro
Partner NPL

Bioeffects/Thermal dose – Author Gail ter Haar

Partner ICR

Measurement challenges/The ideal sensor – Author Piero Miloro
Partner NPL

Module 2

- Take the Module 2 Questionnaire

In this module a background of the problem will be provided. Dr Gianni Durando from the Istituto Nazionale di Ricerca Metrologica (IT) will provide regulatory background, mostly addressing requirements for diagnostic ultrasound scanners, while Dr Antonello Spinelli from Ospedale San Raffaele (IT) and Professor Gail ter Haar will discuss the exploitation of temperature increase for therapeutic purposes, addressing hyperthermia (often in combination with radiotherapy) and thermal ablation respectively. Finally Dr Silvia Pozzi from the Istituto Superiore di Sanità (IT) will provide the background on the use of simulations to predict temperature increase in tissues.

Diagnostic ultrasound – Author Gianni Durando
Partner INRIM

Hyperthermia – Author Antonello Spinelli
Partner OSR

Therapy – Author Gail ter Haar
Partner ICR

Simulations – Author Silvia Pozzi
Partner ISS

Module 3
Technical Solutions for laboratory measurements

- Take the Module 3 Questionnaire

In this module temperature measurements in laboratory environment are discussed. The measurements are made on phantoms, generally composed of tissue mimicking materials. Dr. Aoife Ivory from the National Physical Laboratory (UK) will introduce these materials, their properties and use. Thermochromic materials as temperature sensors will also be discussed. Dr. Raphaela Baesso from the National Physical Laboratory (UK) will discuss about thermocouples as commonly used point sensors to measure temperature. An example of use of thermocouples for High Intensity Focused Ultrasound temperature measurements is provided by Dr Baki Karaboce from Tubitak (TR) as a separate annex to this lesson. Finally, Dr. Piero Miloro will talk about the use of infrared thermography to measure surface temperature.

Ultrasonic TMMs and phantoms/Thermochromic materials – Author Aoife Ivory
Partner NPL

Thermocouple measurements – Author Raphaela Baesso
Partner NPL

Thermocouple measurements demo – Author Baki Karaboce

Infrared measurements – Author Piero Miloro

Partner NPL

Module 4
Technical Solutions for clinical measurements

- Take the Module 4 Questionnaire

The last module will introduce the two basic techniques in use in clinics for the measurement of temperature increase during ultrasound exposure, namely ultrasound thermography, presented by Dr. Nazmul Hossain from the Physikalisch-Technische Bundesanstalt (DE) and Professor Ahmet Baş’s from the İstanbul University-Cerrahpaşa (TR) respectively.

Ultrasound thermography – Author Nazmul Hossain
Partner PTB

MR Thermometry – Author Baki Karaboce