Common problems with Ocular B-Scan machine and where to get it Repaired

There are two main types of ultrasound devices used in ophthalmology practice, A-Scan and B-scan machine. A-scan ultrasound is mainly used for measurement of axial length, critical for intraocular lens (IOL) calculations before cataract surgery. Read more about A-scan here.

B-scan machine is a two-dimensional, cross-section brightness scan. B-scan machine is used to evaluate posterior segment such as retina and orbital pathology, especially useful when a direct view is not possible due to complications or abnormalities. High frequency probes (20MHz)are used to produce high resolution B-scan. As the penetration of higher frequencies is lower, it is used to obtain provide clearer images of anterior segment structures, especially the iris, and ciliary body.

B-scan and A-scan imaging are together used in conjunction to determine the ultrasonic properties (i.e., high internal reflectivity, low internal reflectivity) and size of posterior segment masses, so as to detect different types of lesions.

How does a B-Scan machine work?

The principles of A-scan and B-scan machines used in ophthalmology are the same as other ultrasound-based technology. Sound waves, greater than audible frequency of 20,000 Hz (20 kHz) are generated and reflected back to a probe/transducer by the tissues under study. A piezo-electric crystal in the transducer vibrates based on the returning sound waves, resulting in electrical impulses that are translated into an image.

In B-scan or brightness scan, uses a small, thin ultrasound probe to scan the eye. The probe generates ultrasound waves at a frequency of approximately 10 MHz and receive the echo back from each interface in the eye under study. The received echo is used to produce 2-D images of the parts of eye such as retina, iris, cornea etc.

A B-scan can be performed directly on the anesthetized eye (Source: https://eyewiki.org/Ophthalmologic_Ultrasound). In cases of trauma or in children, B-scan can be performed over the eyelid with coupling jelly. Measurements derived from B-scan include visualization of the lesion, including anatomic location, shape, borders, and size.

Key Components of a B-Scan machine

A typical B-Scan machine has 3 key components:

Ultrasonic probe/ transducer – 10MHz B-Scan Probe is used for normal scans, 20MHz probe could be used for High resolution scans
Control Unit
1. B-Scan Software used to process the acquired images
1. Total Gain Control (TGC)
1. Mouse/ keyboard and Footswitch for operation
1. USB Cable to connect from control unit to display unit
Display unit to display the images

The 20MHz probe, Video Thermal Printer, DICOM Software Package etc. could be optionally available.

Modern B-scan machines or UBM machines could have a very compact form factor like a laptop combining several components.

Control Unit functions

A control unit is the main operating platform to which the probe and the display units are connected. The control unit is used to acquire images using the probe and various controls, such as gain control, independent velocities, automatic capture, automatic alignment indicators etc. A foot switch is used for the measurements. The images and data is transferred to the display screen of the B-scan unit or laptop/computer depending on the type of model. Results can be printed using a printer connected to the display unit.

Major Repair & Service issues in a B-scan machine

The majority of service issues in B-Scan machine are related to its key components such as the probe or transducer, display unit, printer, fault in power supply or mother board, gain control, key board and/ or foot switch. The probe is small and delicate and needs to be handled with care. The main probe issues include, lens damage, crystal damage, oil leakage, motor damage, broken connector, damaged cable etc., most of it repairable.

Ultrasound biomicroscopy

Ultrasound biomicroscopy (UBM) is a B-scan technology utilizing high-frequency (35-100 MHz) probes for high resolution imaging if the anterior segment. A single A/B scan device capable of performing both A-scan and B-Scan are also available.

Popular B-Scan machine models available in the India market are Accutome Keeler, Sonomed, Pirop, i-Orbit, Matronix, Tomey, Quantel, Akas, Nidek, Appasamy etc.

Where can I repair my B-scan machine?

PrimedeQ is an e-Marketplace for buying, selling, renting, servicing and spares of medical equipment. We offer all types of used / refurbished medical equipment , including A-Scan machine and other Ophthalmology equipment, We offer repair services for all types of medical equipment including A-Scan and B-scan repair service, microdebrider, laparoscope , rigid and flexible endoscopes as well as EUS (Endoscopic Ultrasound Units) and ultrasound probe etc.

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