[Intl_DxMedPhys] Dynamic CT Myelogram Protocol - What's a reasonable DLP?

[Tyler Fisher]

Hi Everyone,
Thank you for the thoughtful input on this issue.  I met with the CT team
at this site today and recommended we modify the protocol to 120 kVp with
Auto mA turned on.  We're also hoping to cut down on the number of passes,
rather than doing 4 passes as a default.

I learned this site has performed two of these procedures and I'm proud of
the fact that they raised concerns about the dose.  This is a busy,
medium-sized community hospital but they have a physician who wants to do
this procedure and if it can help patients, we have an obligation to try
and figure out a way to optimize the clinical benefit while keeping the
dose reasonable.  It's been nice for me to see a team of techs and
radiologists come together to figure this out and being able to reach out
to this community for help has been greatly appreciated.

Thank you.
Tyler Fisher

On Tue, Feb 17, 2026 at 8:03 AM Olav Christianson <
olav.christianson at gmail.com> wrote:

> Hi Tyler and all,
>
> This is a timely discussion. For those interested in a deeper dive into
> the clinical and technical aspects of CSF leak imaging, I'd like to
> recommend an episode of the Imalogix podcast, Frame by Frame: Rethink
> Imaging.
>
> The episode, "Why We Miss Spinal CSF Leaks (And What Doctors Do Instead),"
> features Dr. Andrew Callen from the University of Colorado's
> multidisciplinary CSF Leak Program. He covers a number of topics directly
> relevant to this thread, including dynamic CT myelography technique,
> patient positioning strategies, and the challenges of detecting CSF–venous
> fistulas with conventional imaging. For those short on time, the discussion
> around the 26-33 minute mark is particularly relevant to the questions
> raised here.
>
> https://urldefense.com/v3/__https://www.youtube.com/watch?v=Jxaw_pGODGg&t=1s__;!!KGKeukY!1mXMs8JFRJe0uLbjjd30mDQJPLMynMk409EcyGpHLzkW-lHF8WJhDjISdI7szJS8gl6WeqPauCTq4sR37RTmxyWD6kj_d7DJx0Tnww$ 
>
> Best regards,
> Olav
>
> On Mon, Feb 16, 2026 at 12:13 PM Francesco Ria via
> Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list at lists.osu.edu>
> wrote:
>
>> Hello Tyler, I second what Eric mentioned about the high benefit to the
>> patient. A couple years ago we compared, in terms of image quality and
>> radiation dose, myelography with standard energy-integrating detector CT
>> and photon-counting. Average
>> Hello Tyler,
>> I second what Eric mentioned about the high benefit to the patient.
>>
>> A couple years ago we compared, in terms of image quality and radiation
>> dose, myelography with standard energy-integrating detector CT and
>> photon-counting. Average DLP for EID-CT was about 3100mGy*cm; for PCCT it
>> was less than half.
>> I am attaching the article, there are some numbers you can use for
>> comparison.
>>
>> Let us know if you have any comments or questions.
>>
>> Thank you,
>>
>> Francesco
>> ------------------------------
>> *From:* Eric Gingold <Eric.Gingold at jefferson.edu>
>> *Sent:* Monday, February 16, 2026 8:34 AM
>> *To:* Tyler Fisher <sdtyler at gmail.com>;
>> intl_dxmedphys_wd_osu_list at lists.osu.edu <
>> intl_dxmedphys_wd_osu_list at lists.osu.edu>
>> *Subject:* Re: [Intl_DxMedPhys] Dynamic CT Myelogram Protocol - What's a
>> reasonable DLP?
>>
>> Hi Tyler, At my institution, they do CT myelograms as part of an
>> interventional procedure called epidural blood patch, which is used to
>> repair CSF leaks in the spinal cord. Apparently it's remarkably effective
>> at eliminating severe headaches
>> Hi Tyler,
>>
>> At my institution, they do CT myelograms as part of an interventional
>> procedure called epidural blood patch, which is used to repair CSF leaks in
>> the spinal cord.  Apparently it's remarkably effective at eliminating
>> severe headaches caused by these CSF leaks.  These are the highest DLP
>> procedures we have, commonly over 5000 mGycm, sometimes hitting 7000-8000
>> because of repeated long helical scans interspersed with lower dose CT
>> fluoro axial scans.  It's likely that you are looking at the same thing.
>> I've observed some of these and spoke to the neuroradiologist who does
>> them.  He understands that the DLP is high but assured me that the benefit
>> to the patient is extremely high.
>>
>> Eric
>> ------------------------------
>> *From:* Intl_dxmedphys_wd_osu_list <
>> intl_dxmedphys_wd_osu_list-bounces at lists.osu.edu> on behalf of Tyler
>> Fisher via Intl_dxmedphys_wd_osu_list <
>> intl_dxmedphys_wd_osu_list at lists.osu.edu>
>> *Sent:* Friday, February 13, 2026 4:43:13 PM
>> *To:* intl_dxmedphys_wd_osu_list at lists.osu.edu <
>> intl_dxmedphys_wd_osu_list at lists.osu.edu>
>> *Subject:* [Intl_DxMedPhys] Dynamic CT Myelogram Protocol - What's a
>> reasonable DLP?
>>
>>
>> *WARNING: * *External Email - *This email originated outside of
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>> Hi Everyone, A site that I recently began consulting for has a new
>> physician who wants to perform Dynamic CT Myelograms.   The goal of the
>> procedure is to look for CSF leaks in the spine.   The protocol that the
>> physician provided and put on the
>> Hi Everyone,
>> A site that I recently began consulting for has a new physician who wants
>> to perform Dynamic CT Myelograms.  The goal of the procedure is to look for
>> CSF leaks in the spine.  The protocol that the physician provided and put
>> on the scanner, simplified, is below:
>>
>>    1. Patient in Right lateral decubitus position.
>>    2. Prep the skin and advance a 22 gauge spinal needle under serial CT
>>    guidance.
>>    3. Inject 10 mL of Omnipaque-300.
>>    4. Perform 3 continuous passes from sacrum to skull base, then skull
>>    base to sacrum, and then sacrum to skull base.
>>    5. Rotate the patient to left lateral decubitus and do another single
>>    pass from sacrum to skull base.
>>
>> The acquisition parameters for the 4 passes is 140 kVp, 250 mA, 0.625 mm
>> slices.  They're using a GE Revolution scanner.
>>
>> This protocol was loaded and they did a patient.  The total exam DLP was
>> 7,871.89 mGy-cm.  The techs promptly freaked out and have since refused to
>> perform the procedure.
>>
>> So, for the group, what is a reasonable DLP limit for a case like this?
>> Are any of your sites doing this procedure and what doses are you seeing?
>> 140 kVp seems like the wrong kVp for optimizing iodine contrast - what kVp
>> are you using for the passes?
>>
>> Thanks in advance for the wisdom I'm sure someone has out there.
>>
>> Tyler Fisher
>>
>>
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