~ Motors enabling medical imaging ~
Since their discovery in 1895, X-rays have helped us see the world in entirely new ways. Their uses stretch beyond broken bones — even helping us examine ancient Egyptian artifacts and discover the structure of human DNA. While X-ray remains one of the oldest and most used forms of medical imaging, several other imaging technologies have also found their place in the field. Here, Dave Walsha, sales manager at EMS, explores the technology behind precision medical imaging and the drive systems that power them.
Medical imaging is the process of imaging the inside of a body for clinical analysis, most often to look for injuries and disease. Between September 2021 and August 2022, the NHS carried out more than 43 million imaging tests. While X-rays are one of the most common types of test, there are several other procedures a patient may undergo to ensure accurate diagnosis. Many of these rely on small, yet highly accurate, micromotors.
Delivering contrast dyes
For many scans, including X-ray and CT scans, a contrast dye may be used to help the radiologist see organs and tissues more clearly. These dyes are typically iodine or barium-based compounds and limit the ability of the radiation to pass through, changing the resultant image.
Depending on the target area for imaging, the way the dye is delivered can differ. For examination of the gastrointestinal system, it may be preferable to have the patient ingest the compound. For analysis of other areas, it’s often better to inject the patient with the dye.
This can be done using a power injector, which can administer contrast dyes at precise flow rates. This level of precision means that injection parameters such as flow rate and injection volume can be adjusted for each patient and their specific needs. By offering this level of optimisation a better-quality scan can be produced, which can be invaluable when making a diagnosis.
Micromotors enable the motion in these injectors. These motors must maintain a high precision to ensure only the specified amount of fluid is delivered, and run as quietly as possible to reduce disruption to the patient. Space can be an issue for portable injector units, but there are solutions. For example, opting for a flat motor such as those in FAULHABER’s BXT range, which can provide a short drive solution while maintaining high torque, can help save on space without compromising on power.
Taking a look inside
Often used for prenatal scans and diagnostic imaging, ultrasonography uses ultrasound to produce images of the inside of the body. A transducer emits ultrasound waves, which are reflected back when they hit boundaries such as those between tissues. The reflected waves or ‘echoes’ come back to the transducer to generate an electrical signal. Based on how long it takes each wave to return, a picture is slowly built up of internal tissues and organs, allowing imaging to be done in real-time.
The images generated by ultrasonography are usually 2D, using a stationery probe to direct the beam of sound waves. But the view provided by 2D ultrasounds can be limiting, especially as small changes in the angle of the transducer can affect the apparent size of objects. This could alter or hinder a diagnosis.
To prevent this from happening and to improve the quality of the scan, 3D ultrasounds can be carried out instead. In 3D ultrasounds, micromotors are used to manipulate the position of the transducer, which ‘sweeps’ the beam back and forth. By moving the beam while accurately recording each position, the recorded images can be combined to generate the 3D image.
Handheld ultrasonography provides a challenge for manufacturers, with an extremely tight installation space. Stepper motors are ideal for these applications, as they are able to move in tiny increments while maintaining high precision and accuracy. Choosing a motor with high acceleration and the ability to quickly change direction helps to speed up the scanning process.
Whether it’s administering a substance through an IV or directing ultrasound waves, choosing the right electronic components is vital. When the quality of an image can make a direct impact on the diagnosis and resulting treatment of a patient, there’s a demand for drives and motors that can maintain a high precision even under harsh operating conditions and within limited space envelopes.
