A catheter for delivering ultrasonic energy and therapeutic compounds to a treatment site within a patient’s vasculature comprises a tubular body. An isochronous data channel is established within the computer system between a first subset of the plurality of nodes. In accordance with the present invention, a 3-methylthiopropanal with high quality is produced while suppressing the production of by-products having high boiling points. The contact member has an elastic membrane for being brought into contact with the elastic pad.