[Intl_DxMedPhys] Gafchromic film [EXTERNAL]

[Zhang, Da]

This is really cool, Nick! Thanks for sharing!

Da

I may send emails outside your work hours, but please reply whenever it works best for you.


From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces+da.zhang=childrens.harvard.edu at lists.osu.edu> On Behalf Of Bevins, Nick B via Intl_dxmedphys_wd_osu_list
Sent: Thursday, June 4, 2026 10:44
To: DxMedPhys List <intl_dxmedphys_wd_osu_list at lists.osu.edu>
Subject: Re: [Intl_DxMedPhys] Gafchromic film [EXTERNAL]

If you want to make your own rulers (different widths, lengths, film size, etc. ), here’s the script I used to generate the PDFs that Thor sent. You’ll need to download GLE to run the script. I strongly recommend using a few pieces of 11x17 paper
* External Email - Caution *

If you want to make your own rulers (different widths, lengths, film size, etc.), here’s the script I used to generate the PDFs that Thor sent. You’ll need to download GLE to run the script.

I strongly recommend using a few pieces of 11x17 paper cut down to match the film size and running a few test prints. The mammo-sized rulers fit nicely inside an Altoids Smalls tin (which also helps to shield them from light).

-Nick
Nicholas Bevins, Ph.D., FAAPM, DABR, CIIP
Imaging Physicist and Associate Radiation Safety Officer
Maine Medical Center
w 207-662-4276 | p 207-758-0292
nick.bevins at mainehealth.org<mailto:nick.bevins at mainehealth.org>

From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list-bounces at lists.osu.edu>> On Behalf Of Bjarnason, Thor [IH] via Intl_dxmedphys_wd_osu_list
Sent: Wednesday, June 3, 2026 6:19 PM
To: DxMedPhys List <intl_dxmedphys_wd_osu_list at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list at lists.osu.edu>>
Subject: Re: [Intl_DxMedPhys] Gafchromic film

Hi All, Someone posted these a while ago on this mailing list. I have printed one of these out (I forget which one now!) using a laser printer on the film and it came out as an accurate ruler! And then ya, I cut off strips as I need them. I

Hi All, Someone posted these a while ago on this mailing list. I have printed one of these out (I forget which one now!) using a laser printer on the film and it came out as an accurate ruler! And then ya, I cut off strips as I need them. I
Hi All,

Someone posted these a while ago on this mailing list. I have printed one of these out (I forget which one now!) using a laser printer on the film and it came out as an accurate ruler! And then ya, I cut off strips as I need them.

I have about 10 sheets and I think I should be good for the rest of my career … So my caution would only be to not order too big of a box…

Kind regards,

Thor Bjarnason, PhD, PEng, FCCPM
Medical Physicist
Interior Health, Kelowna, BC
Office: (250) 980-6157 | Mobile: (250) 826-0722
Thor.Bjarnason at interiorhealth.ca<mailto:Thor.Bjarnason at interiorhealth.ca>



From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list-bounces at lists.osu.edu>> On Behalf Of Peter Watson, Mr via Intl_dxmedphys_wd_osu_list
Sent: 03 June 2026 9:10 AM
To: Bob Kobistek <bob at rjkmedphys.com<mailto:bob at rjkmedphys.com>>; Douglas Pfeiffer <xraydoug at me.com<mailto:xraydoug at me.com>>
Cc: DxMedPhys List <intl_dxmedphys_wd_osu_list at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list at lists.osu.edu>>
Subject: Re: [Intl_DxMedPhys] Gafchromic film

Caution: This email originated from outside of Interior Health. Do not click links or open attachments unless you recognize the sender, their email address, and know the content is safe. If you suspect this is a phishing or fraudulent email please forward it to spam at interiorhealth.ca<mailto:spam at interiorhealth.ca>.

I've got some old XR-QA2 films that I've been parsimonious with, they are still quite dose sensitive after nearly a decade! I wish they still made this model (good contrast at ~1 mGy, vs the nearly 20 mGy needed for LD-V1). Peter Watson, PhD,
I've got some old XR-QA2 films that I've been parsimonious with, they are still quite dose sensitive after nearly a decade! I wish they still made this model (good contrast at ~1 mGy, vs the nearly 20 mGy needed for LD-V1).


Peter Watson, PhD, MCCPM
(masculine pronouns)

Medical Physicist, McGill University Health Centre

Assistant Professor, Medical Physics Unit and Department of Oncology, McGill University

________________________________
From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces+peter.watson=mcgill.ca at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list-bounces+peter.watson=mcgill.ca at lists.osu.edu>> on behalf of Douglas Pfeiffer via Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list at lists.osu.edu>>
Sent: June 3, 2026 11:32 AM
To: Bob Kobistek <bob at rjkmedphys.com<mailto:bob at rjkmedphys.com>>
Cc: DxMedPhys List <intl_dxmedphys_wd_osu_list at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list at lists.osu.edu>>
Subject: Re: [Intl_DxMedPhys] Gafchromic film

Precisely. In mammography, just need to remember to protect the detector. Best regards, Doug Douglas Pfeiffer, MS, DABR FACR, FAAPM (he/him) Medical Physicist, Radiation Safety Officer Boulder Community Health xraydoug@ me. com 303. 415. 7515 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
Precisely. In mammography, just need to remember to protect the detector.

Best regards,
Doug



Douglas Pfeiffer, MS, DABR FACR, FAAPM (he/him)
Medical Physicist, Radiation Safety Officer
Boulder Community Health
xraydoug at me.com<mailto:xraydoug at me.com>
303.415.7515

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The opinions expressed in this message are the product of the gray and white matter loitering in my cranium. I speak for myself and no one else, unless I say otherwise.

On Jun 3, 2026, at 9:31 AM, Bob Kobistek <bob at rjkmedphys.com<mailto:bob at rjkmedphys.com>> wrote:

Yep, but for stuff like measuring CT beam collimation it doesn't matter. Crank up the mAs to get a good image, then take an image at half the mAs to use as a reference for FWHM. Sensitivity and fog level shouldn't matter


Robert J. Kobistek, MS, FACR, DABR, MRSE(MRSC™)
Medical Physicist
RJK Medical Physics, Inc.
440-463-7879

-----Original Message-----
From: Douglas Pfeiffer <xraydoug at me.com<mailto:xraydoug at me.com>>
Sent: Wednesday, June 3, 2026 11:06 AM
To: Nicole Ranger <nicoletranger at yahoo.com<mailto:nicoletranger at yahoo.com>>
Cc: Bob Kobistek <bob at rjkmedphys.com<mailto:bob at rjkmedphys.com>>; DxMedPhys List <intl_dxmedphys_wd_osu_list at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list at lists.osu.edu>>
Subject: Re: [Intl_DxMedPhys] Gafchromic film

Yup. It just loses sensitivity, in my experience.


Doug
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Sent from my iPhone - please excuse any typos that slip through!
On Jun 3, 2026, at 9:01 AM, Nicole Ranger via Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list at lists.osu.edu>> wrote:

Thanks Bob.  I used large sheets in the past to assess skin dose distributions in fluoro procedures and the results were informative but baselines mattered there.  Glad to know the consensus is that they can be used almost indefinitely for QC.

Nicole


Sent from my iPhone
On Jun 3, 2026, at 11:55 AM, Bob Kobistek <bob at rjkmedphys.com<mailto:bob at rjkmedphys.com>> wrote:

I'd say as long as you can see a useable image, keep using the film. I left some sheets in my hot car over last summer. The sheets are much darker than new sheets, but I'm still using them for CT collimation testing. I can even scan and locate the FWHM with no problems.


Robert J. Kobistek, MS, FACR, DABR, MRSE(MRSC™) Medical Physicist RJK
Medical Physics, Inc.
440-463-7879

-----Original Message-----
From: Intl_dxmedphys_wd_osu_list
<intl_dxmedphys_wd_osu_list-bounces+bob=rjkmedphys.com at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list-bounces+bob=rjkmedphys.com at lists.osu.edu>>
On Behalf Of Nicole Ranger via Intl_dxmedphys_wd_osu_list
Sent: Wednesday, June 3, 2026 9:33 AM
To: DxMedPhys List <intl_dxmedphys_wd_osu_list at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list at lists.osu.edu>>
Subject: [Intl_DxMedPhys] Gafchromic film

Good morning list,

I’ve used Gafchromic film extensively in the past in a dosimetry context where cumulative exposure during storage was important but for the Gafchromic that you use for imaging QC purposes (CT, Mammo, etc…) where the baseline exposure is less important so long as there is adequate contrast, what would you consider to be a useful timeframe before the film is less useful?  Just wondering if there is any downside when buying a box. We have relatively fewer devices here than I have had to support in the past so I’m not sure how quickly I will go through this stuff.

TIA
Nicole


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