Abstract An ultrasonic transducer is improved, particularly for use in perivascular blood flow measurement, by the provision of a coupling member made of a hydrogel. The hydrogel is suitably acrylic based; has a water content in the range from 75 to 90% by weight and preferably about 85%; and has acoustic attenuation of less than 2 dBcm -1 at 5 MHz, with longitudinal velocity of sound and acoustic impedance of similar order to those for tissue. The crystals of the transducer are preferably sealed from the coupling member by a water resistant coating, the member suitably has an exposed face of part cylindrical shape to accommodate a vascular vessel, and the member is preferably releasably mounted to allow size interchange for different vessels.
An ultrasonic transducer comprising a coupling member made of a hydrogel which is mechanically stable in a wet surgical field.
Claim 2
Dependent Claim
20 words
An ultrasonic transducer comprising a coupling member made of a hydrogel which is mechanically stable in a wet surgical field.
Claim 3
Dependent Claim
22 words
A transducer according to claim 1 wherein said hydrogel has a water content in the range from 75 to 90% by weight.
Claim 4
Dependent Claim
15 words
A transducer according to claim 2 wherein said water content is about 85% by weight.
Claim 5
Dependent Claim
51 words
A transducer according to claim 2 wherein said hydrogel has at least one of the following properties: acoustic attenuation of less than 2dBcm -1 at a frequency of 5MHz, longitudinal velocity of sound of approximately 1500ms -1 , and acoustic impedance of about 1.5×10 -6 kg m -2 s -1 .
Claim 6
Dependent Claim
14 words
A transducer according to claim 2 wherein said hydrogel is of acrylic based form.
Claim 7
Dependent Claim
18 words
A transducer according to claim 5 wherein said hydrogel is a copolymer of vinyl pyrrolidone and phenethyl methacrylate.
Claim 8
Dependent Claim
20 words
A transducer according to claim 1 having adjacent said coupling member a crystal component which has a water resistant coating.
Claim 9
Dependent Claim
14 words
A transducer according to claim 7 wherein said coating is of a polyester resin.
Claim 10
Dependent Claim
21 words
A transducer according to claim 1 wherein said coupling has an exposed face concavely profiled to a substantially part cylindrical shape.
Claim 11
Dependent Claim
13 words
A transducer according to claim 1 wherein said coupling is releasably mounted therewith.