“Week 5”: Expensive Machinery

Eugene j -

Hey Everyone! Here is the special post I alluded to, but in what case would I have known that it would be special ahead of time, and what is it about?

This is an image of a 2008 Varian 21iX Linear Accelerator.

This machine can accelerate electrons to near the speed of light to create a beam of radiation precisely shaped to kill cancer tumors. It would cost 3.68 million dollars if sold today, but it is no longer being sold, which means many of the parts to repair it are also no longer being sold. Flagstaff’s hospital has one, and another site has one. In my “Spring Break” post, I mentioned that we can’t open up and repair the expensive machinery because the manufacturers don’t allow us to or it’s too risky. This Friday, I am so fortunate to have encountered a “loophole.”

We bought our linear accelerator in 2013, and after 12 years of running, it is at the end of its lifespan. We will be getting a new linear accelerator. The other site’s accelerator still has a few more years of use, but what if a part breaks down? We likely can’t buy the part, but we need a replacement.

We took apart our linear accelerator for parts.

 

 

 

Look inside and witness forbidden technology.

(And yes, this will be another very technical post now with lots of pictures and some videos.)

I’m sorry for the weird formatting and font sizes. The post looks very different from my editing POV. I tried to fix some of the problems.

 

 

 

 

First, it can spin.

The Varian rotates around a point with an accuracy of less than a millimeter.

For the internal parts of the Varian.

This is the right side of the Varian. I have numbered the parts whose function I understand.

1. This is the main generator. It keeps all essential functions running even if the building loses power. The Varian still needs active building power sent to run the spinning and the linear accelerator, but it will never just lose power mid-function.

2. This is the CPU for the generator.

3. This routes power from the generator to making and keeping a vacuum. The linear accelerator beam must run through a vacuum to avoid collisions with air molecules.

4. This routes microwaves into another part on the other side of the machine to be amplified.

5. This is the RF (radio frequency) driver. It generates electromagnetic waves, which are then amplified to make the linear accelerator beam.

6. This holds multiple sideways circuit boards to run 4 and 5.

7. This is a bucket that is draining out the coolant.

The rest of the wires and such do more stuff. I don’t know the exacts, but they are less specialized.

Here is a better view of the wires.

I presume the gauges and lit number screen are for the internal temperature and cooling system. The red number indicates that the cooling system is currently 39.6°C or 103.28°F out of a max temp of 40°C or 104°F. This is probably because we were draining the coolant.

Posting images and videos to the blog reduces the quality compared to my phone, so that is how I know that it is in Celsius.

Here is a closer look.

Part of me is glad we didn’t need to take this apart.

 

 

 

 

 

 

 

 

 

Here are the systems being pulled out. They have wires at the back that need to be disconnected before they can be rolled out from the railing that they are held in.

These three parts alone easily cost more than $100,000!
Also, in the back is the casing of the Varian and a fake screen window.
This is the left side of the Varian.
Here is where the linear accelerator beam is amplified and moved around.
A beam is made by getting free electrons following a strong electromagnetic wave.
The Klystron Amplifier releases electrons and uses vacuum tubes to amplify the electromagnetic waves.

There is a canister of Sulfur Hexafloride (SF6), a dense, non-flammable gas used for insulation. It is also known as the deep voice gas because breathing it has the reverse effect on the voice as helium.
The golden pathway is where the electron beam is sent through. It is oriented around using magnets. The inside is filled with SF6 to stop the possibility of electrical arcing from the turns.
The beam is sent through a waveguide to become more precise and powerful, but we didn’t remove that part, and I have no photos of it.
Alternatively, this large transformer can amplify the electromagnetic waves.
Then, it is sent out through the x-ray tube. This way, the Varian can do regular X-rays.
The x-rays are released out the right side.
Also, this alone costs $67,000.

This is where the linear accelerator releases the cancer-killing X-rays.

The electron beam runs into a tungsten target and converts it into X-rays.

A plane with an opening in the tumor’s shape is placed on the lens, so the radiation is only aimed at the cancer. The beam would run as the machine spins around the patient, so the tumor at the center gets the most radiation for the longest while the surrounding body gets less radiation.

 

This imaging panel, on the other side of the radiation beam, blocks the resulting radiation. It is made of semiconductors that detect energy, which can be used to see how much radiation is absorbed by the tumor.
Here is the 3.5-inch lead door to the linear accelerator.
The machine is run from another room with the door closed. There are cameras and a speaker, so we can talk to the patient while they are in the room.
Below is what the 2008 Varian 21iX Linear Accelerator looked like at the end.
I know this isn’t directly connected to my project, but I hope you enjoyed seeing this amazing thing!
Thank you for reading this second and (probably) final long post!

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Comments:

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    mae_b
    Wow Eugene! This is really cool. I have a few questions. Firstly, since this one is no longer manufactured, what models are now used to treat cancer tumors instead? And secondly, approximately how many procedures did this machine perform before it was retired?
    April 7, 2025 at 8:49 am - Reply
      eugene_j
      There are many newer models that treat cancer tumors. I don't know exactly what new model the hospital is going to get, but one of them might be the Varian TrueBeam because it is the same type of model that rotates around the patient. For the number of procedures, I don't have an exact number, but linear accelerators are normally used daily. Since it has been in use for 12 years, and assuming it is used seven times a week, it would have performed approximately 4,380 procedures.
      April 22, 2025 at 9:13 am - Reply
    samantha_g
    The pictures and videos are really cool. Were you able to work on the machines and actively take it apart?
    April 8, 2025 at 3:07 pm - Reply
      eugene_j
      Yes! In this case, I was able to actively take it apart. Although that was mainly done by taking out parts and placing them on carts. The other technicians were the ones to unplug the parts from the system. However, I did get to cut a ground wire at the top of the machine, which was surprisingly difficult.
      April 22, 2025 at 9:17 am - Reply

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