r/MedicalPhysics

I am pleased to announce the Gold release for QATrack+ 4.0! This release signifies a return to form for a predictable update cadence, with modernized features. I would like to highlight a few significant aspects of this release:

• On-site installation, upgrade and troubleshooting support is available for Canadian cancer centers courtesy of the CNSC Innovation Grant.
• Remote support, including cloud resources for upgrade testing are also available
• The tools QATrack+ sit on have been upgraded to ensure OS compatibility going forward!  
• Docker install pathway!
• Multiple languages - Draft French and Spanish are included. Professional Canadian French translation is coming.
• A simplified update strategy. Going forward, the update path for patches and non-breaking changes will be:
  1. Stop the site server (Apache/CherryPy)
  2. Run git fetch and git pull
  3. Restart the site server

I need to give a huge shout-out to Nathan Smela at BC Cancer (Prince George) for significant contributions and pressuring me to keep up with the release schedule! Ethan Sutherland from the U of Regina did most of the heavy lifting for being able to support Localization, including the Django 4.2 rebase. 

What's next, and what do I need:

• There will be a poster, and possibly a meet-up at AAPM|COMP 2026 in Vancouver. Come say Hi.
• Community contributions for additional languages!
• A pathway for transferring from one SQL Database type to another.
• We need moderators/community coordinators.
• Get more contributors on board!

Documentation

GitHub

This is the place to ask questions about graduate school, training programs, or general basic career topics. If you are just learning about the field and want to know if it is something you should explore, this thread is probably the correct place for those first few questions on your mind.

Examples:

• "I majored in Surf Science and Technology in undergrad, is Medical Physics right for me?"
• "I can't decide between Biomedical Engineering and Medical Physics..."
• "Do Medical Physicists get free CT scans for life?"
• "Masters vs. PhD"
• "How do I prepare for Residency interviews?"

KLTV (East Texas) recently interviewed Fritz Hager, the medical physicist at the East Texas Cancer Center who investigated the 1986 radiation overdoses with the Therac-25 radiotherapy machine. Although the technical causes of the Therac-25 have been documented for decades, this interview adds valuable first-hand historical detail from one of the key people involved.

A few things that stood out to me:

• Hager describes how he and a technician spent hours after work trying to reproduce the infamous "Malfunction 54" error.
• After successfully reproducing it, he measured a dose of about 15,000 centigray delivered in one-tenth of a second (far beyond a therapeutic dose.)
• He then asked MD Anderson's Dr. Robert Shalit to independently verify the measurement before reporting the findings.
• Rather than waiting for a coordinated response, Hager personally called every known Therac-25 site in the U.S. to warn them. Within hours, physicists at other hospitals were able to reproduce the same fault and connect it to injuries they had already seen.
• The article also includes what appears to be a photograph of the brief Cherenkov flash observed during one of the reproduction tests. I'd never seen that image published before.

One detail I found particularly striking is Hager's explanation that the earlier Therac-20 would simply blow a fuse if a similar operator sequence occurred because it still had hardware interlocks. The Therac-25's reliance on software in place of those interlocks is, of course, one of the central lessons of the case.

If you've only read Nancy Leveson's classic paper or watched the various YouTube explainers, this interview is a worthwhile complement.

I'd be interested to hear from anyone in medical physics or radiation oncology: is the Cherenkov photograph included in this article already well known within the field, or is this the first time it's been published so prominently?

I'm budgeting for an improved CT Density phantom for later this year, currently I just use a CatPhan. I'm seeing offerings from SunNuclear, CIRS, Phantom Lab. Preferably something that works with DoseLab -- I'd prefer not to add any more proprietary software for analysis.

Does anyone have a favorite?

TIA!

For Elekta users who perform the Hancock MLC test on Agility: have you noticed a lack of reproducibility with variations close to 1 mm in some positions between sucesive executions of the test? Like, you do it the first time and one of the segments appears with -0.4 mm absolute deviation, you repeat it after a while and you get about +0.4 mm in the same region, but in other segments the position does not change...

https://preview.redd.it/c6k4cw0mceah1.png?width=1194&format=png&auto=webp&s=58f719e923ec6860fd9b7ef7a910b98a74d7df90

Since each one of the three bands is actually the combination of two images, small differences between the upper and the lower half are not surprising, but differences between consecutive tests seem higher than desirable (even although the absolute deviation is within 0.5 mm for most leaves). I have seen this in three linacs.

Hello,

I am an F-1 rising senior in a Physics BA. I am interested in doing a PhD in medical physics. Due to financial restrictions, I may have to leave the US to pursue an affordable masters elsewhere first then reapply for PhD. I know that if I want to be accredited in the US, one option is to attend an accredited program.

1-But how does residency in the US work if your most recent degree is not from the US, so you can't be on OPT. Is residency then contingent on getting a H1-B sponsorship?

2-If so can international residents share their experience or what they know about how often people in this case get admitted to and attend residencies?

Hi everyone, I’m an undergraduate student interested in pursuing medical dosimetry and applying to graduate school. I’m looking for an opportunity to shadow a medical dosimetrist to learn more about the field and gain firsthand experience. I’m based on Long Island, NY, and would really appreciate any leads or advice. Thank you!

Just curious what everything thinks about not offering a physicist an actual office? I've seen a few clinics where there is just a room, and they throw dosimetry, physics and maybe a few others in there. Not a big fan of this, honestly, but maybe it's more common than I think?

edit Also, how do you feel about timeclocks??

Has anyone else observed a decrease in physicist staffing at their radonc clinic, as in a decrease in the number of physicists per machine? (In the USA in particular.)

I have experienced it at a clinic where the number of physicists per machine decreased from 1 to 2/3. With special procedures, it can be challenging to balance clinic coverage and projects especially when vacation is considered.

Though, an ACR surveyor remarked to me that this is a trend they are seeing.

Has anyone else here experienced this?

Hi everyone,
I’m based in the UK, set to graduate with a masters in medical physics this year. I have been looking at the NHS jobs board for the last year and a bit, and the lack of entry level positions threw me off. I have seen a handful job listings around Band 6/7 level, one or two every month or so. Some people in my masters course have gotten STP or route 2 interviews, however most are graduating without a job.

However, I shadowed a few medical departments and all have told me that they are looking to expand and hire more. If this is the case, then where are the job listings?

Could I ask for guidance from professionals working in the UK?

This is the place to ask questions about graduate school, training programs, or general basic career topics. If you are just learning about the field and want to know if it is something you should explore, this thread is probably the correct place for those first few questions on your mind.

Examples:

• "I majored in Surf Science and Technology in undergrad, is Medical Physics right for me?"
• "I can't decide between Biomedical Engineering and Medical Physics..."
• "Do Medical Physicists get free CT scans for life?"
• "Masters vs. PhD"
• "How do I prepare for Residency interviews?"

Hi
I’m at the beginning of my career in medical physics and I’m interested in measuring dose on skin with and without bolus using gafchromic films.
How do you do it in practice? What software do you use to analyze the films? Is special software necessary or can it be done with free tools?
I’d really appreciate hearing about your workflow and any tips for a begginer :)

Can anyone explain why people use different CT values for the bolus we added for making flash? I have noticed some are using 0, while others use -500 or -200. What is your practice, and what are the pitfalls of using incorrect values? I observed that -500 provides a very stable dose Calculation value from optimisation to the final dose calculation.

Hi,

In Eclipse, do you use virtual or with location reference point ? And why ?

I would personnally use only a virtual one since it’s just a security, but my facility still want to use a point with location.

Please give me your thoughts !

Hi Everyone,

was looking on eBay for inexpensive survey meters (fluke 451) but they are fairly expensive (more than I was hoping). this would be used to measure RLT patients 24 & 48 hours post injection by some Nurses (for Trial purposes). yes the nurses will receive training and be badged, but they need to measure the dose. it's really just for the purpose, and we will only need it for a few months (at this location) so I don't want to spend a ton of money.

Thoughts on accurate'ish 'cheap' survey meters?