ULTRASOUND IMAGE DIAGNOSTIC EQUIPMENT
Rogelio Leyva Ochoa Eng., M.Sc
The word image used here to name the Ultrasound Image Diagnostic Equipment is to differentiate this equipment from the Therapeutic Ultrasound Equipment, but in this paper we´re going to call it ultrasound equipment or UIDE.
This paper is intended to share experience and knowledge regarding Ultrasound Image Diagnostic Equipment for helping the ones who are engaged in servicing this medical technology, and giving some aid to the students. That´s why we try to focus the explanation of the hardware installed in most ultrasound image diagnostic equipment. Years ago to explain the complete hardware of an UIDE it was required knowledge, experience of this technology, and intellectual effort, the service manuals were like a book to acquire knowledge, in which you would learned how to repair the equipment, learn about the technology and it´s physic principles, it happened because it was needed for repairing the equipment, you had to deal with each transistor, resistor, IC etc., that´s why the manual were so explicit. but now because in most medical equipment like in others technologies the repairing work is limited to change boards or the use of some software, so the manufacturer only need to give a brief explanation of the blocks shown on the service manuals, the TGC amplifier or the logarithmic amplifier are shown as blocks , it impossible to show in a service manual one by one all their components as it was done formerly, it is on account of the technology development, that nobody can reject it´s benefits, furthermore the repairing by changing boards save money and time. For the biomed community is so difficult to find a bibliography which treat about the physic principles of most medical equipment and the electronic applied to this equipment, in a book you can find the explanation of an logarithmic amplifier, but it´s application on the ultrasound imaging, so the ones that want to know more than the service manuals offer have to look for another sources, which are not so easy to find, that´s why we try to offer an alternative, it is not possible for us to explain the hole hardware of an UIDE, but we are going to try our best, in some blocks we´re going explain what is inside of some blocks and how they work, like the TGC and Logarithmic amplifiers, other blocks are not possible to be explained by the hardware like the Digital Scan Converter, but an explanation regarding the theory of this block is going to do. We think that even today, as more as you know about the theory of the equipment, the better service you can offer, and more respect you deserve as a professional, because it is not possible for you to repair a logarithmic amplifier, but you have to have a minimum of culture regarding the technology you work with.
As previous papers our purpose is not to use complex mathematical equations, just the needed, while emphasizing on the physical aspects for the better understanding, we´re going to begin with a low level explanation for the beginners better understanding. The explanation begin with of a blocks diagram of an UIDE, this diagram does not go with a specific equipment, it is an attempt to encompass most of the physics and electronics applications these equipment use; latter the hardware of each block will be explained in detail in others coming papers.