Extracorporeal shock wave lithotripsy therapy treatment uses vary from the most widely known and commonly performed kidney stone treatment to other less common uses like heel spurs, tennis elbow, and even gallstones.
The original first generation lithotripter designs had the patient submerged in a bath of water enabling hydrodynamic waves produced by a shock wave generator to have adequate unhindered propagation through water, the patient’s body, and into the kidney stone. Newer second- and third-generation lithotripter designs have the patient apply mineral oil on and around skin in the pathway of the shock wave, a mineral oil coated water bag filled with de-ionized, de-gassed, and distilled water can also be placed between the patient and the shock wave generator. The operator must be continually conscientious regarding air bubbles in the mineral oil and/or the water bag to insure the optimum amount of therapy is delivered.
The smaller portable type systems are typically used for the non-kidney stone procedures. Their fundamental theory of operation is similar, with the exception of the usage of lower levels of KV in the shock wave generator and variations in the coupling medium(s) between the patient and the shock wave generator.
Extracorporeal shock wave lithotripter systems cross the boundary between the skill sets of both an in-house biomedical equipment technology generalist and a radiology equipment specialist. A BMET, radiology equipment specialist or a field engineer should have a fundamental understanding of the individual sections of the lithotripter system to be able to proceed with any type of major repair and/or testing of these devices. These sections include: ellipse F2 analysis, knowledge of water filtration systems, knowledge of ECG monitors, knowledge of high-voltage systems, knowledge of human anatomy, knowledge of computers and electronics, in-depth knowledge of X-rays, and in some cases an in-depth knowledge of ultrasound and 3D positioning systems.
Having worked with these machines in the past, it is quite clear to me that a hospital BMET or Radiology Equipment Specialist would do well to have an adequate amount of research and training under his/her belt before trying to tackle a major repair on one of these devices. The types of problems you can encounter with these machines is extensive especially with the older systems.
Some examples of major problems include:
Some examples of minor problems include:
For various reasons, many healthcare facilities are choosing to lease or pay a fee per usage with many of the lithotripter manufacturers, distributors, and/or dealers in business today. By not purchasing the machine it is very likely that the manufacturer will provide service for these machines. Unfortunately, as those who have been in this industry for some time know, the company’s Field Engineer cannot always make it to the site in the next five minutes. When you have a patient on the table, therapy is in session, and there is that infamous overhead or phone page to the HTM, clinical engineering and/or biomed department you may wish you had touched up on your extracorporeal shock wave lithotripter repair skills.
So, although you may not be personally responsible for these devices at your facility, having a basic understanding of a Lithotripter’s individual sections and some of its common problems may result in you saving the day, getting a well deserved pat on the back from the treating physician and/or staff, or just getting the regular “thank you” from the operator.
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