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Cyth’s Frequency Controller Assists Tomotherapy Cancer Treatment

Circaflex embedded controls.
Circaflex embedded controls.

The Challenge

A developer of a cancer treatment machine approached us with the need for a system to control the frequency output and function of a newly designed tomotherapy device.

The Solution

Using Circaflex embedded control hardware and LabVIEW software, we provided the client with an automated frequency controller accelerating their product’s path to market.

Cancer Treatment

  • Tomotherapy is the targeted use of high-energy gamma rays to fire photons directly into a tumor to kill cancer cells without harming surrounding tissue.

  • A tomotherapy device functions by emitting several thousand X-Ray pulses per second, which are then directionally controlled.

  • Our Automated Frequency Controller (AFC) controls the pulse’s power, frequency, and focus.

  • Our engineering team designed a Circaflex mezzanine board paired with an NI Single-Board RIO (NI sbRIO-9606) to provide the high-speed I/O and programmable control required for the device.

Left: Automated Frequency Controller, Right: Tomotherapy Machine

Patient Process

  • A 3D CT (Computed Tomography) scan is conducted on a patient to help gain 3-dimensional image data of the cancer location and surrounding tissue.

  • The operator transfers the images to the tomotherapy machine wirelessly and within the system control software selects the cancer target location within the patient.

  • The patient is laid on the platform which linearly positions them in the linac machine’s arc.

  • The machine then rotates 360 degrees around the patient and moves in unison with a device called a multi-leaf collimator. The multi-leaf collimator opens and closes quickly to permit or block radiation beams. Different radiation doses go to different parts of the tumor, with less damage to surrounding healthy tissues. The pattern of movement is precisely calculated before treatment starts, so the radiation beams always conform to or are "shaped to" the patient's tumor. In this way, the treatment is personalized to the patient’s cancer.

  • After the machine runs through a set of function diagnostic checks, it once again scans the patient to gain data on their positioning, posture, and breathing patterns.


  • Our Circaflex board paired with the NI Single-Board RIO (NI sbRIO-9606) achieved a data acquisition rate of 20MS/s.

  • The Circaflex mezzanine board provided the MHz Analog Input (Analog-to-Digital conversion or ADC) for monitoring the pulse behavior for the NI sbRIO it was paired with.

  • Pulses arrived at 40 Kilohertz rates from the customer’s pulse generator.

  • With a pulse arriving every 250us, and with a pulse duration of only 400 us, we were required to digitize with 1000 pulses.

  • The Circaflex provided triggering, and the analog I/O was used to control 3 stepper motors which directed the frequency, power, and focus of the pulse generator.

  • After a 10-week design and build period, our team was able to deliver and deploy the system onsite during a 2-day visit.

  • Tomography treatment is delivered continuously from 360 degrees around you. Doctors can also deliver radiation beams from specific, fixed angles. This flexibility gives doctors more control in how they plan treatments — and more assurance that doses will be confined to the tumor.


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