IHERO 2007UseCase Residual Dose Optimization

'IHERO 2007 Use Case Residual Dose Optimization'

1. Proposed Workitem: <Residual Dose Optimization> Proposal Editor: <Nick Linton> Editor: <Nick Linton> Date: N/A (Wiki keeps history) Version: N/A (Wiki keeps history) Domain: <Radiation Oncology>

2. The Problem <Summarize the integration problem. What doesn’t work, or what needs to work.> Goal: Provide a mechanism for repeated courses of radiation therapy while taking the accumulated dose(s) from previous courses into account. Summary: A patient arrives for a second (or subsequent) course of radiation therapy, dose has already been delivered to the treatment volume, and radiation oncologist desires to account for previously delivered radiation dose.

Retrieves (planned or delivered?) dose distribution, CT image, RTSS, and Prescription (out of band). Residual Dose Optimization (“Dosimetric planner with prior dose”)

• Base dose input
• Single, multiple FOR; registration
• Display composite, new dose (radiobiological issues)
• Need RTSS, (RT Plan) for existing dose
• Merging vs. augmenting structure sets
• Maintain three dose matrices: existing, new, composite

3. Key Use Case <Describe a short use case scenario from the user perspective. The use case should demonstrate the integration/workflow problem.> Actors: Patient, Radiation Oncologist, Treatment Planner (Dosimetrist or Medical Physicist). Preconditions: Patient has completed radiation therapy course with planned dose distribution or has aborted treatment at known time and delivered dose distribution can be calculated. Original therapy is any modality from photons and/or electrons, brachytherapy (LDR, HDR, or PDR), particle therapy (protons or ions; scanned or scatted beams). Electronic retrieval and transfer of 3-D dose grid from storage in treatment planning system or DICOM (RT) archive is possible. Triggers: Patient arrives at same institution for subsequent treatment. Or/ Patient transfers to alternate institution for subsequent treatment. Basic course of events: Patient has Prescription, image studies, contouring (manual) and segmentation (manual and/or automatic); treatment planning and dose calculation for first treatment course. Treatment course is completed according to plan. (Therefore the planned dose distribution is assumed to be the best representation of the delivered dose distribution). or/ treatment course is interrupted or abandoned such that remaining Prescription, new image studies, new contouring and segmentation, new treatment planning and dose calculation is required Then/ patient requires subsequent radiation therapy and radiation oncologist desires to account for already delivered dose, physical or radiobiological The existing 3D dose grid (DICOM RT DOSE), anatomical structures (DICOM RT Structure Set) and Image Studies (assuming for all modalities that CT remains that for dose calculation purposes) are available for import into the treatment planning system. Alternate paths: (Included with Or/) Postconditions: New treatment plan is completed and ready for delivery. Business Rules: Assumes that the Use Case for ‘Dose Compositing’ has been implemented. Notes: In theory, all statements above for 3D data could be applied to 4D data (respiratory correlated image studies from CT or CT + PET) ? What if a treatment planning system can accumulate the dose for each fraction using the image data for IGRT (such as kV or MV image studies) ? Authors, Date: Nick Linton & Richard Popple; 7/24/2009

<Feel free to add a second use case scenario demonstrating how it “should” work. Try to indicate the people/systems, the tasks they are doing, the information they need, and hopefully where the information should come from.>

4. Standards & Systems <List existing systems that are/could be involved in the problem/solution.> Treatment Planning Systems, Oncology Information Systems, DICOM RT Archive

<If known, list standards which might be relevant to the solution> DICOM (RT), HIPAA, IEC 62083

5. Discussion <Include additional discussion or consider a few details which might be useful for the detailed proposal>

<Why IHE would be a good venue to solve the problem and what you think IHE should do to solve it.> Many patients have more than a single course of Radiation Therapy. Evern with rigid body registration (research groups and vendors are working on deformable registration) the ability to take previously delivered dose into account is a must. This issue will be even more common when cone beam CT can be used for dose calculation and dose accumuation.

<What might the IHE technical approach be? Existing Actors? New Transactions? Additional Profiles?> A profile with multi- vendor treatment planning seems appropriate.

<What are some of the risks or open issues to be addressed?> Assumption: The plan (DICOM RT PLAN) is required as a link between dose and structure set but is not relevant to the summation – all dose information is in the 3D dose grid. Assumption: the Prescription is not required as the treatment intent. Assumption: for Radiobiological summation, the fractionation and time sequence for prior radiation therapy must be known. It must be clear to the new Treatment Planner which structures are relevant to the original Prescription (the imported Structure Set may include anatomical structures, ‘Helper’ or ‘Avoid’ structures from IMRT plans, and/or IGRT structures such as ‘masks’ or ‘clip regions’). The new Treatment Planning System must be able to import the prior data, register the prior image study (at least, that which is associated with the 3D dose grid) to new data, combine (merge) or augment the structures, account for the delivered dose in the new plan/optimization, create and maintain the single dose matrices and the summed (by physical or radiobiological weighting) doses, display single and composite 3D dose grids Assumption: the new TPS must be able to perform rigid body image registration (i.e. there is not a requirement for deformable registration in this Use Case). Assumption: that the new treatment plan requires some form of automatic optimization (depending upon delivery modality, inverse planning for photon IMRT, could also be for brachytherapy or proton therapy) as accounting for delivered dose by manual re-planning is complicated and unlikely.

<This is the brief proposal. Try to keep it to 1 or at most 2 pages>