1. Prescription to a Isodose : This essentially means that you have a given dose prescribed at a given isodose. The way of choosing this was arbitrary but in my early IMRT days where we were worried about failures we normalized to a percent isodose that covered more than 99.5% (we were looking for 100% though). That meant that if the 95% isodose covers the target we would prescribe to that.
2. No Plan normalization: Allowing IMRT to do the leg work.

Is there any data on this. I could find a paper in medical dosimetry here
The essence of the conclusion is that you can have unexpected high dose or low dose with plan normalization to a percent isodose. To quote the final conclusion of the paper:

….these normalizations help meet the volume coverage goals, but unlike 3D planning situations, may result in avoidable delivery of additional doses to the normal tissues. The focus of this study is to evaluate the effect of application of normalization for IMRT planning using multiple patient situations. Recommendations would favor re-optimization over normalization in most planning situations.

In have seen this situation crop up in SIB IMRT particularly where there was the dilemma of which target volume you select .. usually plan normalization to say 97% for the HRCTV will not imply the same coverage for LRCTV. The OAR doses also tend to increase and that increase needs to be looked after too which I think the authors highlighted in the paper. Having seen the optimization done here at Calgary (i.e. no plan optimization) - I am inclined towards that solution .. if you feel the coverage is not coming reoptimize and get the oncologist involved .. usually the target volume may not have been drawn correctly. Often changing the constraints according to the input of the oncologist and physicist can get a better plan ready.
Optimization to mean and median ? - I guess the result would mean a higher or lower dose depending on where the mean and median is. Then again the question comes which mean and median you choose if you are doing SIB IMRT. Even in simple IMRT the mean or median being measures of central tendency would tend to be affected by the extremes in the dose distribution (particularly for mean). Although it will standardize the plan normalization method it will not standardize the dose distribution I think. Particularly for mean I have seen that it can really show some strange values and the median dose is usually higher than the prescribed dose .. so you would tend to give lesser dose to the PTV if you prescribed to the median than you would if you had no plan normalization or normalization to a isodose.
That said I am not a physicist and input from some of the physicists is welcome here.

Commercial Treatment Planning Systems contain various plan normalization options

e.g

1. No Plan Normalization
2. Plan Normalization at Isocenter
3. Plan Normalization at Target Mean
4. Plan normalization at Target Minimum
5. Plan normalization at Target Maximum
6. % of Volume should Receive _ % of dose
7. Etc.,

Normalization at Isocenter is no long applicable to IMRT

Most of the institute uses no plan normalization. But the pitfall of this normalization method is it may be under dose / over dose to target if the constraints are not properly handled by the planner. So, it is purely depends on the planner constraints & priorities.

I personally would like to use plan "normalization at target mean / Median", which can standardize the plan normalization method in IMRT and it is “independent” of the Planner / user dose constraints & priorities.

I will appreciate if the forum further discuss about plan normalization in IMRT and their institute protocols of IMRT Plan normalization.

1.Do you use Gamma Histograms to evaluate calculated dose distributions against measured ( Portal Dosimetry)?
2.Do you use Gamma Histograms to validate your planning systems ?
3.Is it acceptable to use an acceptance criteria of 3% Dose Difference & 3mm Distance To Agreement (DTA) for all sites?
4.Is it a valid concern that commercially available planning systems bundling different algorithms for Treatment Planning & Dose Calculation and a Monte Carlo for inter-comparison using Gamma Histograms OR Portal Dosimetry licenses for inter-comparison using Gamma Histograms might give a false sense of security during IMRT QA since they are on the same platform and from the same vendor?

Thanking You
Das

We also have a Plugin Development Guide located here: http://code.google.com/p/dicompyler/wiki/PluginDevelopmentGuide

Once you get the hang of things, we should flesh out some more concrete ideas and goals here so that we can decide what toolkits you may need to get this working, i.e. networking, HTTP access, etc.

Currently you cannot contour in dicompyler, however, we plan to get that working this year. We have other things on the priority list i.e. independent DVH calculation, but it is on the roadmap.

Bastula: can you contour/volume on DICOMPYLER?

While this gets away from the whole web idea, we could have the plugin ping a page on the website whenever someone wants to start a contouring session so that others could be notified.

Please see http://en.wikipedia.org/wiki/Collaborative_real-time_editor for more prior art.

I have done this before with http://www.subethaedit.net/ for editing source code and text files and it works great.

You might approach the owner of educase and ask them if they will allow you to place their software on your site. If it is not being used on their site, they might be happy to do this. Alternatively, why is educase not the answer?

Because I have emailed educase guys several times but did not hear back from them . Infact contouring on their site is an option too but i could not find an option to upload my own dicom files. I can anonimyze them before upload so they are available for public use.

This is only a DICOM-RT viewer at present. We might use that by providing a DICOM-RT file without contours on www.isocentre.org and then uploading your contoured DICOM-RT file to a site like Dropbox on a public directory.

I contacted Aditya Panchal the developer of DICOMPYLER. He is still working on the software getting features into it. It coded in python and I am hopeful we will be able to integrate it sometime in future.

The SSH Tunnel and XDMCP software are an interesting suggestion. Supposing I host a TPS on a server do you think XDMCP can allow access to remote users from say a windows machine using a web login interface. I am not too knowledgeable about these things but recently we have started wondering if we should shift the site backbone to a CMS like drupal so I am investigating options like these

There is also a R&V/TPS open source system called "open RADART" from Austria that runs Elekta machines. It is a very large installation and instructions are in German.

DICOMPYLER

This is only a DICOM-RT viewer at present. We might use that by providing a DICOM-RT file without contours on www.isocentre.org and then uploading your contoured DICOM-RT file to a site like Dropbox on a public directory.

TPS

Getting a TPS on line may just be a case of setting a machine up for VPN access. Also Linux machines have software called XDMCP (X Display Manager Control Protocol) which can be accessed over a SSH tunnel to use software remotely.

EDUCASE

You might approach the owner of educase and ask them if they will allow you to place their software on your site. If it is not being used on their site, they might be happy to do this. Alternatively, why is educase not the answer?

1. http://www.radonc.washington.edu/medinfo/prism/
2. http://planunc.radonc.unc.edu/about/

Both are open source solutions doing a lot more than what we require. What I want is some help from any of you guys for any ideas on how to itegrate them with us. What I have in mind is hosting them from a webserver and allowing users to login remotely via internet and using it for contouring purposes. We need an online collaborative environement so a given number of users may contour on the same patient at the same time
Any ideas guys?

Got any ideas about how this might happen?

Anyone got any potential for research with a nanotechnology team?