Developing IGRT protocols

Summary:

Need to develop/ agree on protocols for imaging in IGRT considering the different sites, techniques, type of registeration, landmarks, use of fiducials, correction strategy, thresholds, and frequancy of imaging for different vendor solutions

Developing IGRT protocols

sandeep jain 26 Dec 2010 14:37

Dear Collegues,
There is a need to develop/ agree on protocols for imaging in IGRT considering the following issues:
1. Differences with different sites and technique employed
2. The type of registeration/ fusion (manual or automated)
3. Bony vs soft tissue vs fiducial matching
4. Which bony, soft tissue landmarks to take
5. The correction strategy (offline, daily online corrections)
6. When to do autoshift vs shift on markers
7. Threshold for calling physician and physicist
8. Frequancy of imaging in different sites
These issues may be different for different vendor solutions with different resolutions.
Like to get peoples experience utilizing literature information.

Re: Developing IGRT protocols

adjuvant 26 Dec 2010 16:19

I have a question about cone beam ct,
What is the main difference between CBCT and diagnostic CT?
Is the energy always KV?
And which sites are best imaged with CBCT?
Thanks,

Re: Developing IGRT protocols

Santam Chakraborty 26 Dec 2010 21:21

Hi,
CBCT need not be always KV as MV CBCT technology is available. The pdf here gives a nice overview of MVCBCT http://www.aapm.org/meetings/amos2/pdf/26-4423-93268-365.pdf
As far as differences in between conventional MDCT and KV CBCT are concerned there are many. I have provided some of them in a tabular format in the attached file. CBCT technology was first used for dental work so much of the info is taken from dental specific CBCT systems.
KVCBCT vs MDCT
As far as sites go the limitations of the CBCT make it apparent:

1. You can image an area with good contrast difference accurately eg. bone soft tissue interface
2. You can image an area with little motion better
3. You can image a smaller area better

So typically CBCT can give a good picture in head and neck region and prostate region.

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Re: Developing IGRT protocols

adjuvant 26 Dec 2010 21:52

Thank you very much. It was very helpful