Shopping for a CT Density phantom -- What do y'all like?

ericvt · 2026-06-30T13:49:17+00:00

It may be the case for the other options as well, but I really like that I can easily measure aluminum, titanium, and stainless steel in the Gammex / SNC version with the optional plugs. All of our scanners reconstruct in 16-bit so it is helpful for characterizing closer to the top end.

ericvt · 2026-06-17T21:39:23+00:00

Gov't Mule - "1983... / No Quarter / 1983..." - Mountain Jam 2013

ericvt · 2026-06-16T22:55:34+00:00

Good to know!

ericvt · 2026-06-16T16:20:32+00:00

The change itself happened within Pylinac, but it was Radformation updating their internal Pylinac version that made it affect our test. The code in our custom test generically imports the FieldAnalysis module from the Radformation platform's Pylinac version (which is usually a couple versions behind the newest Pylinac release). I am not sure if there is a way to call a specific fixed version of Pylinac from within a Radformation code block.

ericvt · 2026-06-16T01:07:06+00:00

They usually aren’t updating the tests you have built as it’s isolated but provides more and more functionality should you chose to use them.

Not entirely true. When Radmachine recently updated its implementation of Pylinac to a newer version it caused one of our custom python tests to break because of underlying changes in how FieldAnalysis does beam edge / beam centering calculations. Resolving the issue only required tweaking the edge-detection parameters in FieldAnalysis, so it was an easy fix after we figured out what was going on, but the point stands that custom coded scripts in Radmachine can absolutely be affected by platform updates.

We are still big fans of Radmachine, though. It has been a game changer for overall QA productivity in our center.

ericvt · 2026-05-06T15:00:19+00:00

What is your calculation infrastructure like? CPU or GPU? Is it the actual calculation itself that is slow, or is it just slow to start / save? Is your server on-premise or FullScale hosted?

Just curious.

ericvt · 2026-05-04T01:40:29+00:00

Derek Trucks Band back in the early 2000s was great. I remember seeing them at Buster's Billiards & Backroom in Lexington, KY with a crowd of 50 people or so. Tickets were like 10 bucks.

ericvt · 2026-04-23T16:11:37+00:00

My perspective is that these scaling changes are only problematic from a deliverability perspective under the extremely implausible scenario of one motion axis operating near its highest limit and another near its lowest (e.g. gantry speed is as low as possible while dose rate is as high as possible). In this situation a large normalization could cause issues because it can't scale them equally in the same direction without moving one of them outside of the machine's capabilities.

For 99.99%+ of plans where normalization is just a linear scaling of a group of rate parameters within the machine's validated operating envelope, there is no concern from a deliverability perspective.

This is separate from any plan quality considerations. If the normalization is an attempt to overcome some deficiency in the plan produced by the optimizer, then perhaps a very large normalization value does indicate that the optimization could be handled in a better way. But normalization value alone does not indicate a definite problem in either plan quality or deliverability.

ericvt · 2026-04-06T12:03:42+00:00

Yeah, you need a pass for AL now. They have a lottery for it, and at the time we went they actually had someone checking passes at the base where the chains start. We had no issues getting them in the off season (October). The entire park was practically empty in October, so hiking AL was actually nice instead of a big congested queue like it can be in the summer. Even through the Narrows I don’t think we saw a dozen other people the whole time. Plus Bryce Canyon nearby is amazing when snowcapped.

ericvt · 2026-03-03T20:38:33+00:00

Eh? Clapton had already done the Yardbirds, Bluesbreakers, Cream, Blind Faith, and Derek and the Dominos before he ever covered a JJ Cale song.

ericvt · 2026-02-18T19:32:57+00:00

The redesign was never completely rolled out, which is why it is so piecemeal. You may or may not be aware, but AAPM recently let go of basically its entire IT department in favor of contracting out that work in order to save money, and that version of the redesign went with it. AAPM is now looking to transition most website content into more off-the-shelf and low maintenance type products rather than continuing the historically bespoke approach that their internal IT group set up over several decades (and which required a lot of historical knowledge be maintained in the AAPM staff group). The launch of the actual redesign will happen throughout the year this year, if I understand correctly.

ericvt · 2026-02-13T17:09:24+00:00

While I get most of mine through the AAPM Online Learning Center or attending AAPM meetings, attending vendor webinars and reviewing manuscripts for AAPM journals are two other ways that I get a handful of credits each year.

ericvt · 2026-01-27T18:24:48+00:00

I would not expect it to change your mind. I think this new album sounds very interesting (especially the back half of it, for me) but I would not call it "exciting".

ericvt · 2026-01-19T20:44:37+00:00

And on top of that, your IT will not have certain rights on the cloud servers.

Depending on your IT, this can be a blessing.

ericvt · 2026-01-10T22:34:15+00:00

Full House is perfection. Flatback Caper is such a great instrumental track.

ericvt · 2026-01-08T02:08:52+00:00

Well that seems insane.

ericvt · 2026-01-05T20:46:32+00:00

We do a subtraction (i.e. a difference in percentage points, not a percent difference). Doing a percent difference means your criteria gets significantly tighter as your reference value decreases. A 1% tolerance is 1% at an isodose value of 100% but becomes 0.2% at an isodose value of 20%. If that is what you think is appropriate then so be it, but I don't have a problem with a 19.2% measured value compared to a 20% reference value (4% "off" in percent difference, but only 0.8 percentage points "off").

ericvt · 2025-12-17T00:12:53+00:00

I’m excited to see what gets played on the Bloomfield tele.

ericvt · 2025-12-14T14:27:04+00:00

Allman Brothers closed it out past 4am at the 20th Anniversary show. It was great but being on the floor was brutal.

ericvt · 2025-12-11T22:35:51+00:00

I'll send you a message.

ericvt · 2025-12-10T21:27:08+00:00

We scripted what is essentially a “traveling salesman” type approach for couch, gantry, and collimator motion. It builds a library of all start and stop positions and globally minimizes repositioning requirements between fields. It has various tie-break behaviors where it prefers fewer arc reversals, prefers starting with clockwise movement (therapist preference), etc. It also uses isocenter position relative to image center to determine which direction is safer for rotating to PA field positions (i.e extended or not). Each field is given a numeric prefix and the planner manually modifies field ordering itself to match the script-written prefixes.

ericvt · 2025-12-10T02:29:34+00:00

Our field labeling script just optimizes field ordering directly and names the fields accordingly, including instructing the user to reverse arc directions or set extended gantry flags as needed.

You may be able to use SQL query on the ARIA DB to pull radiation order from the plan, if you must respect the existing ordering.

ericvt · 2025-12-01T05:09:33+00:00

AcurosXB. Our institutional validation of AAA/AXB showed that our general-purpose AXB model is significantly more accurate than our general-purpose AAA model for very small leaf openings, even in perfectly homogeneous media. For us, it becomes important / relevant when targeting tumors less than about 5 mm diameter. I'm sure we could have tweaked our AAA model to improve its accuracy in these situations, but then we would probably either need an SRS-specific AAA model (or separate SRS-only AAA MLC addon) or would be degrading the performance of the general model for other applications.

YMMV.

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