How do you contour the cauda equina for a lumbar spine SBRT case below the spinal cord?
Do you add a PRV on this?
Community PollStarted
For spine SBRT below the cord, do you routinely utilize a PRV for the cauda equina or lumbosacral plexus, and if so, what is your PRV margin?
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2 Answers
Mednet Member
Radiation Oncology · Lynn Cancer Institute - Baptist Health City, Baptist Health South Florida
Answered on
I typically contour the cauda equina at the level of the upper lumbar spine just below the spinal cord based on T2-weighted MRI and utilize a 2 mm PRV. If the entire spinal canal is instead contoured just below the cord, this may lead to underdosing of the posterior aspect of the vertebral body.
At t...
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Mednet MemberInvited Expert
Radiation Oncology · Memorial Sloan Kettering Cancer Center
Answered on
I typically use a 1 mm PRV for cauda and 0 mm/no PRV for lumbosacral plexus.
There are a variety of constraints you can use.
Robert Timmerman, PMID 34919882
- 1-Fraction
- Cauda: D0.03cc < 16 Gy; D5cc < 14 Gy
- Sacral Plexus: D0.03cc < 16 Gy; D5cc <14.4 Gy
- 3-Fraction
- Cauda: D0.03cc < 25.5 Gy; D5cc < 21....
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