x -ray system

have you tried google or any other search engine? i came up with 1,160,000 answers.

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1-what is HF x ray system?

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There is no such thing in X-Rays. X-rays are not WAVES [Frequency] but are RAYs too-higher to be named as wave.

There are types of X-Rays generated in different applied Voltage:

Soft X-rays normally generated at <35KV. These rays are absorbed by human-body mostly & are dangerous for Human exposure.

Hard X-rays generated at >100KV - they pass through human-body & used now-a-days as standard for Human Exposure as these are not absorbed at all

Indusrial X-rays >500KV for material flaw testing

Do not hesitate to ask more.

For info: In which Institute are you studying

BE(bio medical equipment)from pakistan?

I am Biomedical Engr trained at Siemens Institutes in Germany & worked 35 years as Service & Installatins Engr,

Refer to:

http://health.howstuffworks.com/x-ray1.htm

The PCX HF high frequency generator family matches the needs of busy radiology departments with today's technology. The coherence of touch screen and color LCD display offers a unique generator control with great flexibility in powering a variety radiographic and fluoroscopic applications. The integrated self diagnostic ensures trouble free operation and comprehensive service

Specifications

Power Rating

30-80 kW

kV range

40-150 kVp

mA range

20-1000 mA (depending on the generator power)

mAs range

0.4-600 mAs

Exposure time

3 ms-6 sec.

Fluoroscopic kV

40-120 kV

Fluoroscopic mA

0.5-10 mA (25 mA in Pulse Fluoroscopy)

Power Requirements

From 240 VAC single to 480 three phase

Features

• Microcontroller and computer integration deliver reliability and accurate exposure parameter management.
• APR operating mode with 160 examination distributed across 8 anatomical regions. Simple and user-friendly technique reprogramming on site.
• Automatic parameter correction for patient thickness, tissue density, film.screen speed and source image distance.
• Manual override technology permits the operator to modify the recommended kV, mA and time.
• Sophisticated self-diagnostic capability and descriptive error messaged allow for fast and well-defined initial diagnostics.
• Compact display console is ideally suited for small control rooms.
• Comprehensive service program provides accurate troubleshooting and minimize downtime.
• Automatic tube overload protection, selectable 80% or 100%.
• Automatic Exposure Control can support either four solid state detectors or ion chambers.
• Automatic Brightness Stabilizer produces optimal fluoroscopic images.
• Supports one or two x-ray tubes in either radiographic or radiographic and fluoroscopic mode.

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simply speaking, hf x ray system---- high frequency x ray system.
the generator is linking to a high frequency voltage source.
which is higher than 10khz corrresponding to 5ohz voltage source.
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Equipment is not designated by Mains Power Source but according to their FUNCTION.

It could be "The HF Generator Operated; X-Ray Unit or Plant" and not "HF X-Ray Unit or Plant"

Power Source in KW above 400 Hz [for Avionics like Aviation uthorities] is not known to me.
Foundries use MF [around 5 KHz self Resonating Power Furnaces] but those cannot be used as power source for X-Ray set-up.
Though the requirement is for mS.

It is correct that @ higher freqs size & bulk of Load [HV Generator ] is much smaller than @ 50/60 Hz

Any how thanks for clarifications, though I doubt if Hi-Power X-Ray exposure can be attained @ Single Ph Power Line.
Flouroscopy can be be done OK

One Piont to be noted that:

1.) Power-lod of X-Ray Plants are not like Continuous Loads. These are Very Fast & need such responce-times from Mains-Lines

So
2.) Power-Line's Impedance should match the I/P Impedance of "HV Generator" otherwise Exposure @ 150KVA [150Kv x 1A]for approx 4mS will be too ideal.
A well conditioned line is arranged with the co-operation of Power-Agency which is damn difficult to be arranged.

How shall I explain it? there are many denomination different from textbooks in pratice.
X-ray tube, as a vaccum tube, has a large inner capacitor and cannt be applied with high frequency voltage on it. if you do it, that means short circuit. so we used to rectify to DC by a rectifier to apply on it to produce x-ray. ( the filament can be applied by hfv)
hf is only a vltage generator.

simply speaking,

hf x ray system---- high frequency x ray system.

the generator is linking to a high frequency voltage source.

which is higher than 10khz.

corrresponding to 5ohz voltage source.

Welcome to biomed, Rasheed! I have been in the field since '82 and it has been good to me. Practical benefits of an HF generator system is a more compact generator and use of much smaller high voltage transformers.

Dave Meador

Morning, Dave,

your description is right, hf method can use smaller transformer, which can reduce weight, size and increase facility!

you must be very experience at the field for you make it so long time. Can I ask several questions?

How hight frequency do you ususal use? 20k, 33k or 50k or higher than 200kc?

how much voltage do you generate? power? or ma?

cnpower--

Normal range for HF generators is 5 to 100 KHz. The Siemens engineer, Haajee has a good handle on the specifics and is familiar with more modalities than just medical x-ray.

The most valuable things to know in the medical field x-ray are the most common failure causes. For instance, Haajee commented on incoming power. If you don't have good steady voltage coming in a well-maintained and tight distribution system, the dropouts and transients (also called power events) will kill the x-ray system. Transients will kill off anything using microprocessors for control. I favor using Sine-Control products on the distribution panel to control transients.

Another problem that kills systems is too much heat. Without proper air conditioning, the electronics will overheat and rapidly deteriorate--ususally failing intermittently and driving engineers crazy. I use an overheat prevention maintenance procedure that is done monthly that cleans out all filters and air inlet grilles and checks that all air fans are running. This simple procedure can prevent 50% of system problems. Some engineers have an attitude that they do not touch dirt and filter cleaning is dirty. These engineers usually have equipment that doesn't work well--because their equipment is dirty and overheated. For instance, $250,000.00 USD ultrasound units and echocardiography ultrasound equipment will run great if all the filters are clean. If the filters are dirty and the units overheat, they will not work right and will cost an average of $10,000.00 a board to repair. The most valuable tool in electronics maintenance is the vacuum cleaner. The second most valuable is the air compressor (to be used in conjunction with the vacuum cleaner).

The one thing that drives succesful medical maintenance is failure analysis. Why did the device fail? Do enough failure analysis and you find that there are about 20 things that cause electronics to fail. If you control for these things, you have almost no problems. It also makes troubleshooting much simpler. Using a 20 item check list, most people can troubleshoot 80% of problems in any device in 20 minutes (and do it without fancy test equipment).

Biomed is a fun and challenging field. Enjoy!

Dave Meador

Thanks & Regards for your ralavent comments.

Hi, Dave,

I dont agree to you somewhat. I agree that most fail is at ppower supply, but the very most of mordern, especially medical x-ray apparatus are made of HF power.

Backward last 80's, many of CT are supplied by HF. from supplied to control system to generator. I hve ever repaired some CT, which is failed at power and they were all in way of HF.

I know htat in china now, almost all CT are supplied by HF at 33Khz or 50Khz.

They can be zvs or zcs power supply and have higher efficiency.

HF can offer very steady voltage and lower ripper more than LF or MF voltage, they can use little capacitor and inductor. Its obviously.

siemens is a very famous company, their equipments are all supplied by HF.

Like them, our safe equipments are all supplied with HF as well.

I admit the industry frequency equiment is less fail than HF.

but you can only see them in musium. and I can only see one of them in our service shop corner.

sometimes, hf is not very difficulty to repair. change mosfet or igbt, enough.

hf is only a vltage generator.
industrial x-ray apparatus can be up to 1000kv but medical is less than 150kv with large current, say 1.5A or 3A etc at very instant time. most of them are around 60--75kv.
Both of them can be sused HF of 33kc or 50kc, now up to 100Khz etc.