System Description

During minimally-invasive surgery (cardiac, vascular and neurological), surgeons need technology to be able to see what they are doing. Interventional X-ray systems provide real-time visual images based on X-rays. The patient lies on a table and is positioned between an X-ray tube and an X-ray detector. Based on the detected X-ray, the system reconstructs a visual image and displays this to the surgeon on a screen.

Outside Perspective

In this subsection, we describe the system as a surgeon sees it and uses it.

Hardware components

• Table to support the patient (the patient lies on top of the table);
• Pedal board with 3 or 6 pedals for the surgeon to control the system;
• 1 or 2 X-ray planes, each consisting of one X-ray tube and one X-ray detector that are physically aligned to each other (the two planes are called Frontal and Lateral, respectively);
• Screen to display visual images to the surgeon;
• Tablet for the surgeon to configure the system by selecting a medical procedure.

Interaction

During a medical procedure, the surgeon uses the pedals to select the type of X-ray generated by the whole system in terms of the following notions:

• Dose (= amount of X-ray): low or high
• Projection (= which X-ray plane(s)): Frontal, Lateral, or Biplane (= Frontal + Lateral)

A system with 1 plane has 3 pedals:

• 1 pedal for low-dose X-ray streaming video
  • Press = start
  • Release = stop
• 1 pedal for high-dose X-ray streaming video
  • Press = start
  • Release = stop
• 1 pedal for something outside the scope of this assignment

A system with 2 planes has 6 pedals:

• 3 pedals for low-dose X-ray streaming video (one for each projection)
  • Press = start
  • Release = stop
• 1 pedal to select the high dose projection
  • Press = select the next projection in a round-robin fashion
• 1 pedal for high-dose X-ray streaming video (on the selected projection)
  • Press = start
  • Release = stop
• 1 pedal for something outside the scope of this assignment

While using low-dose streaming video, surgeons need to be able to temporarily switch to high-dose streaming video, without releasing the low-dose streaming video pedal.

Inside Perspective

In this subsection, we describe some of the internal components that this system may be composed of.

Software/electronic components

• PedalMapper: Mapping pedal actions (press/release for a specific pedal) into X-ray requests (e.g., start/stop for a specific type of X-ray).
• ActionLogic: Resolution of (possibly conflicting) X-ray requests, thus transforming X-ray requests (e.g., start/stop for a specific type of X-ray) into X-ray commands (e.g., activate/deactivate for a specific type of X-ray).
• XrayController: Control and synchronization of the X-ray tubes and detectors based on X-ray commands (e.g., activate/deactivate for a specific type of X-ray). The XrayController expects an alternation of activate and deactivate commands. At activation, it first prepares the X-ray tubes and detectors. Then, it synchronizes their execution using timed pulses and receives X-ray images from the X-ray detector until deactivation.
• ImageProcessor: Processing of the X-ray images into highly readable visual images.
• SystemConfigurator: Configuring the settings of the XrayController and ImageProcessor components based on the current system configuration and a selected medical procedure.
• ProcedureDatabase: Database with all possible system configurations and component settings for various medical procedures. Each system configuration consists of a combination of specific system components.