Good morning! I built a "simulator" for a mobile radiography unit console. To "simulate" an exposure, the "preparation" button must be pressed and held until the filament LED turns on; then a simple click on the "exposing" button triggers the emission of "radiation". The "simulator" aims to help biomedical electronics students in their imaging module. I would be grateful if you could test it (link below) and give me suggestions to enhance it, especially on the following points: 1) the idea itself, 2) does it really help, 3) further enhancements.
The URL:

https://alitronic-lab.github.io/Xraytrainer1/

 

Its difficult to assess how 'correctlt' the simulator actually simulates the machine without knowing quite a lot more detail. However, things seem to function as I would expect, and the execution is neat. The one problem is that, when more than one line of diagnostic data is shown in the panel above the adjustment buttons, then rest of the diagram jumps downwards. You need to put a blank line after the initial condition (Ready to prepare...) so that the display area stays a consistent size.

 

Its difficult to assess how 'correctlt' the simulator actually simulates the machine without knowing quite a lot more detail. However, things seem to function as I would expect, and the execution is neat. The one problem is that, when more than one line of diagnostic data is shown in the panel above the adjustment buttons, then rest of the diagram jumps downwards. You need to put a blank line after the initial condition (Ready to prepare...) so that the display area stays a consistent size.

Thank you! I will try to fix that.

 

Ahh, this brings me back to when I worked for Phillips Medical Systems, and we were designing a diagnostic X-ray generator. Admittedly, this was 50 years ago. The simulation seems generally pretty nice for function and features. It seems like a it would help a student to make sure he sets all parameters before making an exposure on a patient.

On the X-ray generator we were designing the "Prep" button was part of a two-stage pushbutton exposure switch. The prep button was a raised central button surrounded by the ‘exposure’ pushbutton. In its use, the X-ray technician would partially press the “Prep” button and hold it until the “Ready” light came on. At this point, the technician would fully depress the prep/exposure button to initiate the exposure. The exposure timer (“Time” on your simulator) controlled the exposure time according to the parameters set.

When the technician released both buttons, another timer would be initiated that would prevent an additional exposure being made. This timer as I recall was around 5 minutes. The purpose of this timer was to prevent the patient from receiving a double-exposure and to give the rotating anode time to cool down.

The purpose of the ‘Prep’ sequence was to give the rotating anode of the X-ray tube time to come up to full speed (about 25,000 RPM) so it would not melt or cause pitting from the 10 KW or so of power being applied. This would typically take about 3-5 seconds but did vary with the exact X-ray tube that was being used. The required time for the “Ready” light (not ‘Filament ready’) to come on was set by the installation team and would not be changed unless the X-ray tube was changed.

I have used the term “Prep” instead of Prepare because that is how the panel was marked. It was also how virtually every person, engineer, doctor, technician referred to it in speech. I don’t believe there was a “Reset” button either. Timers and switch settings negated the need for having one. It might be useful strictly in a simulator application though.

With the above procedure in mind, for your simulator you could perhaps make a 3-position ‘slide’ switch (Standby / Prep / Expose) that would initiate the appropriate timers. The student would HAVE to return the switch to the “Standby” position which would initiate the “Reset” function. Additionally, I would make the prep and post-exposure timers in real time so that students learn to wait for the required timers in real time.

While I have used 3 seconds for the prep time and 5 minutes for the anode cooling time, I would consult actual X-ray tube data sheets to finalize the required times.

A normal sequence (and exceptions) would be as follows:

Switch Position​	Student Action​	Results​
Standby	Student sets up exposure parameters A/R.	Display as you currently have (allowing for 2 lines of text).
Preparation	Student moves switch to the Prep position. They should be encouraged to wait for the “Ready” light, giving them time to review the parameters. If the student moved the switch to the Expose position, the 3-second timer MUST count down before the exposure can occur.	The 3-second timer counts down until the “Ready” light come on. If the student moved to switch to the Expose position, the exposure would occur after the 3-second timer times out.
Expose	Student moves switch to the Expose position.	After the 3-second timer counts down AND the exposure switch is in position, the exposure occurs according to the parameters entered.
Standby	Student returns the switch to the Standby position.	This simulates the student removing their finger from the Prep/Expose button. This action initiates the 5-minute timer only if the Expose position was entered.

Depending on your desired training goals, the exact console actions and results could be varied based on how and when the student moves the switch position. It could quickly make a much more complex and potentially inaccurate simulator if you are not careful. I would suggest the above as a minimum though.

I have a couple of additional comments on your simulation which may improve the overall simulator realism.

• I would like to see the settings buttons for kV and possibly, mA and Time automatically count up or down if you just hold the button. (I personally found one separate push per step for kV very annoying.)
• This may or may not apply to a more modern design of generator, but as an Engineering tech at PMI I spend a lot of time taking data on the mains current and voltage drop so that an accurate prediction of the actual X-rays produced could be anticipated. I was essentially measuring the circuit resistance so that losses could be predicted and compensated for. Perhaps the modern-day equivalent of could be added to your QA/Calibration tab.

Overall, a very nice job on your Trainer Consol simulator.

 

Overall, a very nice job on your Trainer Consol simulator.

Thank you for taking the time to review my project. Coming from someone with your experience, your feedback is really appreciated.

 

I suggest that if the TS is able, to get a copy of the manufacturer's operators manual. Then make copies of the portion about safe use of the system.
( I see the link, maybe the TS did that already)

My concern is that the damage done by X-RAYS is not visible right away, unless the over-exposure is massive.
Like from an older X-ray machine, sometimes available quite cheap. It is very simple to bypass all of the radiation safety portion, and do lots of damage.

 

My concern is that the damage done by X-RAYS is not visible right away, unless the over-exposure is massive.
Like from an older X-ray machine, sometimes available quite cheap. It is very simple to bypass all of the radiation safety portion, and do lots of damage.

All true statements. From the simulator panel design, this would seem to be a training panel for what is known as a Diagnostic X-ray machine (as opposed to a Dental X-ray machine).

Diagnostic machines are versitile machines designed to X-ray any part of the body that a doctor needs information about, and therefore quite powerful. The one I worked on could be set anywhere from 40 kV to 120 kV, 1 mA to 1.2 amperes, and I believe up to 1.2 second exposures could be made. The maximum power was 100 kW. At that time (mid-70's) the primary "sensor" was film. Today, electronic sensors are exclusively used and have a MUCH higher sensitivity than any film ever did.

I'm not an X-ray technician, but generally more dense tissues (i.e. the liver) require higher tube current and thicker body areas (i.e. the chest) require higher voltage to get a proper exposure with minimum X-ray energy. Exposure time is the variable that is used depending on area exposed and to compensate for the sensitivity of the sensor used. It can also be used to make a 'deeper' part of the anatomy become visible. To minimize tissue damage, the lowest possible voltage and the lowest "mAs" should be used consistant with image quality.

It is the responsibility of the technician to set up the machine parameters appropriate to the doctor's request for information. The technician has to take into account the patients body weight, build, etc. There is some judgement call because voltage, current and time are somewhat interactive not only on the clarity of the X-ray, but also on the potential damage caused to the body by X-rays. But that is why you go to school to become an X-ray Technician.

 

My single effort toenter the medical technology sector was dismissed by the preliminary assertion that ENTRY required a "Doctorate Level" degree in the area.
I am not even interested in working with those who hold that sort of attitude.