RTOG H-0022                Corvus Data Transmission to ITC                         April, 2003

Procedures for Sending both CTV and PTV Structures, based upon the TJU approach.

 

The user must independently define on two separate plans, one containing user defined the CTV and  the other containing the user defined PTV, as the ITC is not able to read the Corvus defined PTV’s.  The first plan will be a standard plan and will be the plan used to insure that the protocol requirements are met.  This plan will be used by the ITC to read the CTV’s.  The second plan will contain the PTV’s and will be a phantom plan using the same patient CT data set.

 

The following procedures assume that the contours have been defined external to Corvus, e.g. on AcQsim or some other virtual simulation platform.  If the contours are being defined on Corvus, it will be necessary for the oncologist to define the appropriate structures on both the standard plan, which contains the user defined CTV’s, and the phantom plan, which contains the user defined PTV’s.

 

Each Corvus institution is asked to define an H-0022 structure set, which contains the following structure names:

 

Standard Name                                     Description

 

Brain_stem                                            Brain stem

Larynx                                                    Larynx

Mandible                                               Mandible

Mandible_Lt                                         Left Mandible

Mandible_Rt                                         Right Mandible

Parotid_Lt                                             Left parotid

Paroitd_Rt                                             Right Parotid

Skin                                                        External patient contour

Spinal_cord                                           Spinal cord

PTV66_1                                                Planning target volume 66 Gy

PTV66_2                                                Planning target volume 66 Gy (assuming a second 66 Gy PTV)

PTV60_1                                                Planning target volume 60 Gy

PTV60_2                                                Planning target volume 60 Gy (assuming a second 60 Gy PTV)

PTV54_1                                                Planning target volume 54 Gy

PTV54_2                                                Planning target volume 54 Gy (assuming a second 54 Gy Gy PTV)

GTV                                                        Gross Tumor Volume

GTV_PTV                                              Gross Tumor Volume grown to PTV

 

 

1.        Generate a treatment plan, beginning with the patient info mode.  Enter all appropriate information.  Enter “Patient” as the treatment plan type.  In the Image Registration mode, identify and process the pertinent items.  Set the ROI such that it encompasses the entire CT data set, i.e. 512 x 512.  (In Version 5 and above, the data sets are automatically made square.)

 

2.        After image registration, enter the Anatomy Mode and edit tissue (skin).  Exit the plan and copy the plan.  The purpose of this is to generate two data sets with identical external contours.  For the second data set, enter “Phantom” as the treatment plan type and modify the name to include PTV.

 

3.        Return to the patient plan type (the first data set).  In the Anatomy mode, use the DICOM-RT structure association tool to associate the GTV and all CTV’s.  Remember to associate in order of small organs to large organs and higher dose to lower dose volumes.  The parotids should be associated before the nodal chains.  The cord, mandible, and brainstem should be associated before the skin.  Do not associate any user defined PTV’s.

 

4.        After the associations have been made, enter the Prescription mode.  Set the localization uncertainty to 5 mm or greater.  As Corvus’ users know, this will define the Corvus PTV’s.  Define all prescription parameters such that the H-0022 protocol requirements are met.

 

5.        Review the final plan to insure that all H-0022 specifications are met.  (When this plan is sent to the ITC, they will read the all CTV’s, the parotids, the mandible, and the brainstem.)

 

6.        Now exit and enter the second phantom plan.  (Remember that you must first run a simple plan in order for any phantom plan to included on the list of phantoms.)  This second phantom plan will have the same external contour as the first plan.

 

7.        Enter the anatomy mode and use the DICOM-RT structure tool to associate the GTV with the GTV-PTV.  Use the Grow Filled Structure Operator to grow the GTV_PTV by 5 to 10 mm, depending upon clinical judgement.  Do this for all slices which contain the GTV_PTV.    For the most superior and inferior slices, the growth the GTV_PTV is left to the judgement of the user.  The user can copy the previous contour to the superior or inferior slice and then shrink it by 3 mm.

 

8.        Use the DICOM-RT structure tool to associate the CTV66 with the PTV66_1.   Grow this by 5 mm.  Please remember to start with the highest dose smallest volumes.  Do the association and then the growth one volume at a time. 

 

9.        After all of the volumes have been associated, calculate a simple plan so that this phantom will appear on the list of phantoms.  Wait for this simple plan to be calculated.

 

10.     Exit from the second phantom plan and go to the Select Plan Screen.  Highlight the first plan and go to the Create hybrid Phantom Plan from Study.  Select the second plan as the phantom plan.  Enter the coordinates of the selected study’s calculation point and the coordinates of the phantom document’s measurement point.  (These two sets of coordinates should be the same.)  Perform the calculation on the phantom plan.  

 

11.     After review, send both plans to the ITC.  As noted above, the ITC will extract the CTV contours from the patient plan and the PTV contours from the phantom plan.