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Evan Altenhof, Rapid Prototyping for custom cancer treatments

Meet the interviewee: Evan Altenhof Evan is a Design Machinist at the Tom Baker Cancer Treatment Centre design lab, a dedicated workshop for medical physics. At the TBCC, he leverages his a broad skillset in rapid prototyping to develop custom solutions for simulating treatments, positioning patients, and delivering therapies most effectively and safely, using a wide variety of additive and subtractive manufacturing techniques on a daily basis. Key words: additive/subtractive manufacturing, radiation therapy, medical physics, tissue phantom

Evan stands next to a 3-axis computer-numerically controlled (CNC) mill used for manufacturing metal products.

What does the TBCC do, and how does the Design Lab contribute to that goal? The Tom Baker Cancer Treatment Centre uses radiation therapy and chemotherapy to treat cancer patients. [The Design Lab] builds phantoms for testing prior to clinical use, as well as machine calibration and setups. We also build patient mobilization equipment to constrain the patient during the radiation or imaging applications. We also build and repair anything the radiation therapists bring to us; we modify existing products to suit their needs. We’re really encouraged to challenge ourselves in how to build things, and think outside the box, experiment… which is quite nice!

What tools do you find you’re using on a daily basis?

  • Hands! Hands are the #1 tool.

  • Your brain.

  • 3D printers: have a lot of use in the medical space. I think medical is actually the largest [application space] of 3D printing technology. I think automotive is second, but all industries are getting into it.

  • CNC router/CNC milling machine: For subtractive manufacturing.

Every tool in that shop gets used quite a bit!

What’s the advantage of having the Design Lab on -site, rather than having to work with a contractor or outsource this work? What does the TBCC gain by having the Design Lab so close by?

Well first of all, you get a better relationship between the physicist and the people working in the design lab, which contributes to greater quality product, revisions on the fly, faster turnaround times. You’re able to actually interact with these people on a daily basis; you’re able to design and build things that are exactly tailored to their needs. With outsourcing you wouldn’t get those kinds of interactions.

In a situation in which cancer is progressing quickly, that’s life or death, that delay time?

Yeah. And ensuring people get that radiation therapy when they’re scheduled.

Linear accelerator under preventative maintenance.

Would every hospital have a design lab like this? Or is this unique in Alberta? That’s a great question, I’m not entirely sure. I know for a fact that the Foothills Medical Centre has a machine shop/welding shop, and it’s to build and repair hospital equipment. We’re more focused on the cancer treatment side. As for other hospitals, I can see them having a maintenance facility, I’m not so sure about a dedicated medical physics design lab.

What are some projects that you’re working on right now?

(Chuckles) Well I actually just finished building some “foot guards” for a child’s total body irradiation bed. It’s so that the therapist’s feet don’t get run over by the wheels. That’s an example of a day-to-day modifications of existing equipment that doesn’t have a clinical application.

We also machined materials that have the same density as human bone, and foam that has the same desnity as human lung. We build these “phantoms” - that’s what we call them - because they’re better for testing radiation delivery than on a person.

We’ve built models that mimics human tissue, on which they practice brachytherapy. Brachytherapy is still radiation therapy, but instead of the linear accelerators delivering the dose, it’s a series of tiny, rice-sized titanium-coated iridium seeds that are placed near the tumour, that emit the radiation, and then they are removed. We build these phantoms so that they can practice these more invasive surgical techniques.

We’re also in the midst of building catheters for gynebrachy therapy. These catheters are placed in the patient, and they’re able to direct the dose for an asymmetric dose distribution. The catheter is placed inside the patient with the radioactive seed. They’re also able to remove [the inside portion] and place a 3-dimensional ultrasound down the tube, and make sure that the needles with these radioactive seeds in them are in the correct place.

With this device, physicists will move the patient to the OR, install the catheter and and position needles containing the radioactive source. And they want to make sure that they’re in the right spot, but in order to do that they previously would have had to install them, move the patient down to the CT room, CT scan them, then they’d find out the needles aren’t in the right spot, take them back to the OR, adjust… So they’d have to move the patient lots of time, and you have needles in there, you don’t really want to be moving that much! So this solution allows for a 3d ultrasound without having the move the patient during the procedure.

So it’s really quite different stuff than the Oil and Energy industry.

Definitely [and solutions like these] come out with needing to do things quickly, have information when you need it, and the fact that there is this relationship with the clinician who can see what the problems are and work with you guys to develop a solution.

Definitely. I always wished that I was the “what guy”. I’m the “how guy” but not the “what”. I need other people to be the “what”.

How did you get into this career, in this role?

I got out of highschool, my parents made the recommendation that I go to college. Thankfully they did, and thankfully I did. So I picked Mechanical Design Technology at SAIT. It was primarily product design, building, etc. Once I was done that I was looking for a job I couldn’t find anything in the industry, mostly because I was so green. I found a job at a small family-run manufacturing facility just east of Calgary. I started in Shipping and Receiving, and then I worked my way up to Assembly, and then they threw me on computer-controlled machines, (which I had no idea about, but at that time I was just pressing the green button, making them run, and loading and unloading the parts).

During that time, I was going to school for computer-numeric controlled programming. Then I got a job at TransCanada; I worked there for 7 years in the machine shop, as the repair/development machinist. So i’d design all their fixtures, write all the programs, do all the first-off repairs. Then I worked in field service for a little bit, as the admin person (which wasn’t very fun - I like to get my hands on stuff).

One day, I just needed a change and I saw (on Indeed or some website like that) that the TBCC was looking for a machinist. And I thought “Why are they looking for a machinist? What could they be doing here that they’d need a machinist?’ Like, you don’t think about that stuff. And in the meantime, luckily, I had bought a 3D printer - stereolithography, Formlabs Form 2 - and i had been playing with that at home making, molds with that for urethane casting. And I’m glad I was doing that because I think that’s what set me apart in the interview. I wasn’t just a machinist that knew how to program the machines, I was also experimenting with additive manufacturing, and what tool had to offer, so it gave me a leg up.

The need for flexibility in that shop really comes across - you’re using one machine day - or one minute, and another the next. Knowing how everything works is pretty critical.

And being able to use them safely, yeah.

How does working here fit into your career plan?

I quite like working here. Everyone is super-friendly. Most of the shapes that we have to reproduce or manufacture are organic - no two people are the same, so one size doesn’t always fit all. The material that we’re asked to also comes with their challenges. Not all materials act the same when being machined, or poured, or printed. They do encourage experimentation - thoughtful experimentation - which gives me an opportunity to challenge myself knowing that I’m not going to get into huge trouble for trying something new.

I love making stuff - whether it’s programming, electronics, 3D printing, making something out of wood, I don’t care - The more stuff like that I can learn, the more versatile I am, and the greater success I’ll have to be able to build that product for someone who needs it.

The TBCC is equipped with a objet stereolithography 3D printer, shown here printing bite blocks. What are some exciting things to watch for in radiation therapy? Proton-beam therapy. Conventionally, electrons and photons are used. The electrons are accelerated and they hit the plate, and the photons emitted are used for deeper-tissue therapy. The electrons, if they’re not hitting that target, aren’t used because they don’t penetrate deeply enough. But photons have their drawbacks: there’s lots of scatter, photons don’t lose their energy when they hit their target, they carry on and can give secondary cancers from the radiation treatment. So now instead of electrons they’re using protons. From what I’ve heard they’re harder to ‘steer’, but they’ll travel through the skin, travel to the site, and when they hit the target they dump all of their energy so you don’t have any backscatter of the radiation. This makes it better for applications where you’re treating near sensitive areas like the optic nerve, in the brain, and the spine.

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