This technical report is relevant to the measurement and specification of ultrasound fields intended for medical therapeutic purposes. Lithotripsy and physiotherapy are excluded, since there are existing International Standards for these applications. It establishes: • topics where there is a consensus that the development of International Standards would benefit the industries and/or patients; • topics where the writing of standards should start immediately; • topics where the writing of technical specifications should start immediately in order to gain practical experience and establish consensus prior to standardisation; • topics which require future standardisation but where further research is required before initiating the writing of standards or technical specifications. This report addresses primarily the requirements for measurement standards related to high intensity therapeutic ultrasound (HITU) [also known as high intensity focused ultrasound (HIFU)] fields which are both high intensity and focused and where the main mechanism for action is thermal. However, aspects of the discussion, conclusions and any resulting standards or technical specifications may also be relevant to therapeutic applications which are either focused or high intensity or where the main mechanism is not thermal. Scientific literature has been reviewed and responses to a questionnaire which was sent to experts around the world are reported.