This protocol describes the use of a fully automated system, the Radiation Planning Assistant, to create high-quality radiation treatment plans. So the Radiation Planning Assistant, or RPA, can improve treatment planning workflow, should be especially useful for clinics that have limited resources. The RPA also automates most of the contouring process.
This should significantly reduce the amount of time that the radiation oncologist needs to spend on the treatment plan. The algorithms used by the RPA have been extensively evaluated by experienced radiation oncologists, including quantitative evaluation of dose distributions. Many parts of the RPA, including contouring of normal tissue for head and neck plans, are now in routine use in our clinical practice.
I'm also using the automatic field creation for cervical cancer in my daily practice. The user needs to get used to some new interfaces, including plan approval and CT approval interfaces. The visual demonstration provided here should help with this.
Open the Plan Order workspace using the standalone icon or from the Radiation Planning Assistant control center workspace. To create a new Plan Order, first click New. Complete section one, Demographics.
Enter the medical record number and patient name. Select the appropriate Treatment Site. Choose from head and neck, cervix, breast, and others.
Next, complete section two, general treatment. Complete the questions on sex/pregnancy status, prior radiation, pacemaker, and other implants. Complete the question on auto start or technician.
Then, complete section three, Treatment Specific. Select the head and neck primary site and positive lymph involvement by selecting the appropriate radio button. Subsequent sections are automatically selected based on these choices.
Confirm or change the sections on cervical neck and retropharyngeal lymph node coverage by selecting the appropriate radio button. Then, select the appropriate radio button to indicate whether these correspond to CTV1 or CTV2. Next, select treatment machine and treatment technique.
Select the treatment approach by clicking on the appropriate radio button. Confirm or change the treatment prescription. To change the prescription, enter the required fraction doses into the text boxes.
Then, confirm the appropriateness of the normal tissue dose constraints. Save the Plan Order, and a PDF of the Plan Order will be generated. Review the final Plan Order.
If the final Plan Order is correct, click on Approve. To approve CT images, click on the CT Approval icon. Click on the CT scan that is to be approved.
Review the CT slices centered on the isocenter. Click on Load All to review all CT images. Review isocenter location and CT image quality.
If the CT images, number of slices, orientation, and data are correct, click on approved. Wait for the patient data status to indicate W in the control center. It is now ready for contouring review.
Click on the W icon or on ROI Approval. The contouring review and approval workspace will open. Review all contoured tissues and targets.
To edit structures, first select the structure of interest from the pull-down list. Then, click on the nudge icon, and edit the contour on each CT slice. If necessary, manually delineate the gross tumor volume and positive lymph nodes.
To do this, select the structure of interest from the pull-down list. Click on the manual delineation icon, and draw the structure on each CT slice. Next, create clinical target volume for head and neck cases.
To expand the GTV in positive lymph nodes, click on GTV to CTV. To manually draw CTV1, select CTV1 from the list of structures. Click on the manual delineation icon, and draw the structure on each CT slice.
Review and edit CTV1 as necessary. Click on CTV to PTV and review. Edit if necessary, but remember these expansions account for the many uncertainties in both contouring and patient setup.
To edit the PTV, select the appropriate PTV from the pull-down list. Click on the nudge icon or one of the other editing icons. Review all the contours and then click on Approve ROI.
Once the ROIs are approved, the treatment planning process will proceed automatically. Pay attention to any warning messages and add explanatory notes as necessary. Review the treatment plan when it is ready.
It appears as a plan review document in the control center. Perform the technical review and the final plan transfer as described in the text protocol. The dose distribution for an automatically generated VMAT plan for a patient with a base of tongue squamous cell carcinoma is shown here.
A review by an attending radiation oncologist confirmed that this plan was acceptable for treatment. The shaded regions show the planning target volumes. Red corresponds to PTV1, blue to PTV2, and yellow to PTV3.
The lines show the isodose distribution of the automatically generated plan. Shown here are automatically generated field apertures for a four-field box treatment for a patient with cervical cancer. Review by an experienced radiation oncologist confirmed the clinical appropriateness of 90 to 96%of these fields.
On average, these plans took 21 minutes. Shown here are illustrated instructions designed to aid a chart review for radiotherapy plans automatically generated using the RPA. This example page is for the review of the automatically generated body contour.
It includes the results of the primary algorithm, some questions for the user, and a Library Case for the user to review. After watching this video, you should have a good understanding of how to create radiotherapy treatment plans using the Radiation Planning Assistant. It's important to remember that plans generated by the RPA must be reviewed by qualified staffs, including radiation oncologists and medical physicists.
In order to help initial plan quality, the RPA includes extensive internal and independent calculations. These are used to automatically verify the quality of the individual aspects of the treatment plan, that including those calculations, field apertures, and the contours. Currently, the RPA can automatically create VMAT plans for head and neck treatments and four-field box plans for cervical cancer treatments.
We are actively adding additional anatomic sites, including chest wall.
