Ultrasound phantom material

I am writing this letter in response to an article which appeared in the BJR in 1982 (Lerski et al), and which has recently come to my attention. We invented an ultrasound tissue-mimicking phantom utilising polyurethane reticulated foam in the late 1970's. We filed a United States Letters Patent application on May 4, 1979, and subsequently a U.S. Patent was issued to us on September 1, 1981 (Ophir et al). As a matter of record, this device has been manufactured under licence and sold worldwide by Acoustic Standards Corporation since mid 1979, under the trade name Ecobloc™.