HDR Prostate Planning | HMH Medical Physics Resident Resources

Phase 1. Treatment Prescription

1. Navigate to Treatment Management

Navigate to Quicklinks > Treatment Management > Prescribe Treatment

2. Create a New Course

Click the drop down arrow and select New

3. Enter Course Details

Course name: C1a (first HDR treatment) or C2a (second HDR treatment)

4. Select Treatment Template

HDR Prostate Boost (Shared) for boost treatment
HDR Prostate\SV (Shared) for monotherapy
This auto-populates the Treatment Prescription pane (e.g., One Fraction)

Phase 2. Contouring

5. Rename CT Image

Right-click on the CT Image box (top left) > Properties
Change ID to CT HDR Prost Fx1 (adjust fraction number as needed)

6. Add HDR Prostate Treatment Structures

Navigate to Structure > New Structure from Template > Dunn HDR Prostate
- This adds: PTV, Prostate, Rectum, Urethra, and Bladder

7. Contour Structures

General Contouring Tips

Quality of life: Hover over the CT display to see protocol structures. To show the structure names permanently, right click the small icon near the top left corner of the display and uncheck Auto-hide Structure list
Efficiency: Contour every 3-4 slices, then click Interpolate Structure on the vertical toolbar and Apply
Quality Check: Scroll through all slices to verify interpolated contours and adjust as needed

Contrast Agent Considerations

We use Iodine-based contrast agents to improve visualization of the urethra and bladder. However, if the patient has a contrast allergy, imaging will be performed without contrast. In non-contrast cases:

Sagittal views become essential for accurate urethra contouring
Physician input and guidance is particularly important
Fused MRI (if available) can help due to better soft tissue contrast

Rectum

CT Identification:

Tubular structure posterior to the prostate
May contain air (dark/black) or soft tissue density (gray)

Contouring Guidelines:

Inferior boundary: Anorectal junction (where puborectalis sling creates posterior angulation)
Superior boundary: Rectosigmoid junction (where bowel deviates laterally/anteriorly, typically S2-S3 level)
Wall: Include entire rectal wall circumferentially
Key point: Maintain clear tissue plane between rectal wall and prostate

CT Tips:

Use abdominal windowing to distinguish wall from contents
Contour entire structure despite air-fluid levels
Verify continuity on coronal and sagittal views

Hydrogel Spacers (SpaceOAR, Barrigel)

Some patients may have hydrogel spacers between the prostate and rectum from prior external beam treatment. These spacers can be difficult to discern on CT and may appear similar to soft tissue. If uncertain, review prior treatment records or MRI images to identify spacer boundaries.

Urethra

CT Identification:

Runs through prostate center from base to apex
Slightly lower density on CT; better visualized on MRI
With contrast: appears as bright structure due to Iodine uptake

Contouring Guidelines:

Superior boundary: At least extend up to the internal urethral sphincter (you can continue into the foley)
Inferior boundary: Anterior tracking section, at least 2 cm away from the closest applicator
Diameter: Typically 5-8mm
Path: Follows natural anterior concavity through prostate

Tips:

If Foley catheter present, contour around it
Verify continuity on sagittal views
Without contrast: rely heavily on sagittal/coronal views

Bladder

CT Identification:

Large pelvic organ superior and anterior to prostate
Fluid-filled with low CT density; thin soft tissue wall

Contouring Guidelines:

Inferior boundary: Bladder base/neck (superior prostate aspect)
Superior boundary: Bladder dome (extend above high-dose region)
Include wall only, not just lumen

CT Tips:

Filling varies—adapt to patient anatomy
Wall typically 3-5mm when moderately filled
Use coronal views to verify extent and wall continuity

Needles in Bladder

If your digitized needles appear to pass through the bladder contour, this indicates an incorrect bladder contour—not an actual needle placement issue. Needles should never be placed through the bladder. Review and adjust your bladder contour to ensure anatomical accuracy.

Non-Prostate Cases

Some patients treated with this protocol may not have a prostate (e.g., post-prostatectomy with local recurrence). In these cases, anatomical landmarks and contours will not follow typical appearance. Exercise additional caution and consult with the physician for guidance on target and OAR delineation.

8. Perform Image Fusion (Optional but Recommended)

Image Fusion for Contouring

Locate relevant imaging studies (MRI, PET) to assist the physician with target delineation. Image fusion can be performed before or after contouring, depending on workflow preferences.

Navigate to Quicklinks > Imaging > Image Registration
Check the horizontal chronological image display for available studies

When Imaging is Not Available

Check Epic for available imaging studies and treatment planning notes
Review patient notes to identify which imaging study was used for disease identification
Import that specific study if available
Best practice: Import the most recent study of the same modality as the one used for disease identification for anatomical relevance

Create Image Registration Link

Double-click the CT study to select it and display in all views
Right-click on desired source image (e.g., MRI study) and select Manual Match
In the New Rigid Registration window that appears, verify:
- Source Image: Secondary imaging (e.g., MRI or previous fraction CT)
- Target Image: Planning CT with existing contours

Click OK, you should see a line connecting your Source and Target images (A)
Obtain approximate alignment using the Manual Match tool
- This involves translating and rotating the images until a reasonable alignment is achieved
Click Auto Matching in the toolbar
Configure Auto Matching Region:
- Adjust the registration region dimensions to focus on the prostate and surrounding anatomy (C-D)
- Click Start to begin automatic registration (B)

Second Fraction Workflow

For second fractions, you must fuse the CT from the first fraction to the new CT to import the prostate contour. These structures (Prostate and PTV) are needed for optimization and will be reviewed by the physician.

Steps for Second Fraction Structure Import:

First, align the current CT with the previous fraction CT using the image registration workflow described above
Once aligned, import the prostate structure from the previous fraction
Use the Margin for Structure tool to expand the imported prostate with the following values:

The physician will verify and adjust these imported structures as needed before proceeding with planning

Phase 3. Planning

Plan Naming Convention

When creating your plan, use the following naming conventions:

HDR_Prst_Fx1 (or Fx2) for the first (or second) fraction
HDR_Prst_Boost for boost treatments
The naming should reflect whether the treatment is boost or monotherapy

3.1 Creating a Plan

9. Navigate to Brachytherapy Planning

Navigate to Quicklinks > Treatment Planning > Brachytherapy Planning

10. Open the relevant course and imaging set

11. Create new plan

Insert > New Plan > Select your Brachytherapy Course (e.g., C1a) > Next >

12. Select RT Prescription

Select the prescription from Phase 1 > Next >

13. Select Plan Target

Choose Prostate > Next >

14. Configure Plan Properties

ID: HDR_Prost_FX1 (adjust fraction number as needed)
Target Volume: Prostate
Technique: INTERSTITIAL
Number of Fractions: 1
Treatment Percentage: 100 %
Dose per Fraction: 1350 cGy (boost) or 1500 cGy (monotherapy)

Fraction count

Prostate plans are always 1 fraction since we create a new plan for each fraction. In HDR Cylinder, the plan uses 5 (or 3) fractions, changed to 1 when sending to Mobius.

3.2 Insert Applicators

15. Create First Applicator

Insert > New Applicator... > Select Treatment Unit (e.g., Bravos - Dunn) > OK

Treatment Unit Selection

Ensure you select the correct afterloader (Treatment Unit) for the clinic where the treatment will be delivered. Using the wrong afterloader can cause delivery errors and treatment delays.

16. Configure Applicator Properties

Double-click applicator icon in data tree:

ID: Needle_1
Channel length (cm): 125
Step size (cm): 0.50
First source position (cm): 0.1
Last source position (cm): 4.00 (adjust later as needed)
Dead space (cm): 0.4

17. Duplicate for Additional Channels

Copy and paste applicator once per expected channel

3.3 Digitize Applicators

Template-Based Cases

For template-based implants, use the assisted digitization method (3.3.1). For freehand implants without a template, manual digitization (3.3.2) may be more appropriate.

Channel Numbering

During digitization, select channel numbers based on your template sheet, which records the grid locations and assigned labels for each applicator/needle.

18. Align CT to Template

Rotate axial plane parallel to template's flat face
This ensures high-intensity points match the template pattern

19. Orient for Template Comparison

Adjust the viewing orientation so that the needle arrangement on screen closely resembles the template sheet from the OR
The goal is to make channel identification straightforward by matching the visual pattern
This allows easy verification that each digitized needle corresponds to the correct template position and label

3.3.1 Assisted Digitization (Template Cases)

20. Select Appropriate Axial Slice

Navigate just beyond the template where needle arrangement still matches template sheet

Slice selection

Avoid navigating too far from the template—bending can distort positions. Select a slice beyond the template for better detection while maintaining easy channel identification.

21. Optimize CT Display for Needle Visualization

Set window/level to Abdomen range
Increase upper HU limit to better visualize metal needles and dead space (bright tips)

22. Detect First Applicator

Select first channel in data tree (Applicators folder)
Click Detect applicator from volume image
Click on needle location in image
Configure settings: Metal and Straight for Ti needles
Adjust Threshold until applicator region appears green in Detection Threshold window
Click Detect Selected

23. Detect Remaining Applicators

With Detect Applicator window still open, select next applicator (e.g., Needle_2)
Click corresponding needle on axial slice—should turn green if threshold is correct
Click Detect Selected
Repeat for all remaining applicators following steps (1) - (4) below, where (1) involves checking your template sheet

Digitization activation

Detected digitizations are not active until modified using the edit, rotate, or translate tools

3.3.1.1 Adjust Tips and Source Positions

24. Adjust Needle Tips

Right-click applicator name in data tree > Move Viewing Planes to Tip
With Contour Editor tool selected, adjust the last point (tip)

No undo available

You cannot undo in this module. If you accidentally add a new point (added from the end, not tip), left-click to remove it. For more serious distortions to the applicator, it may be easier to re-digitize the applicator.

25. Update Last Source Position

Physician-Drawn Contours

The prostate contour must be drawn by the physician before you can accurately adjust the last source position to match target margins. Coordinate with the physician to ensure the prostate structure is finalized before proceeding with source position optimization.

For each needle, adjust Last source position property to prevent dwell positions from extending beyond target margins
Extend value if initial 4 cm is insufficient

26. Inspect and Refine

Review digitization using Draw applicator-plane intersections with given diameter
Verify the following quality checks:
- Continuity: Each applicator appears as a continuous line without breaks or jumps
- Template accuracy: Needle positions match the expected template grid locations
- Tip position: Tips are positioned appropriately relative to target anatomy
- Dwell position count: Number of source positions is appropriate for target size

3.3.2 Manual Digitization

27. Optimize CT Display

Refer to step 21 above for CT window/level optimization to visualize needles

28. Align Viewing Planes

Rotate viewing planes so needle's central axis is approximately coplanar with sagittal and coronal planes

29. Digitize Using Contour Editor

Select Contour Editor tool
On sagittal or coronal plane, click along applicator length to add points
Continue until all potential dwell positions are included
Click and drag orange squares to adjust digitization
Right-click orange square to remove a point

30. Adjust Tips and Source Positions

Follow steps 24-26 above to refine tip positions and update last source position values

3.4 Dose Optimization

3.4.1 Add Clinical Goals

31. Navigate to Clinical Goals

Planning > Add or Edit Clinical Goals...
From Select Clinical Goal Template dropdown, select HDR Prostate
Click Ok

3.4.2 TG-43 Volume Optimization

Clinical Goals Required

Clinical goals must be assigned to the plan before performing VEGO TG-43 optimization. If you encounter an error during optimization, verify that clinical goals have been added by navigating to Planning > Add or Edit Clinical Goals... and following the steps in section 3.4.1 above.

32. Initiate Optimization

Planning > Modify Dose > VEGO TG-43 Volume Optimization
Click OK when prompted about normal tissue structure creation

Start with Current Dwell Times

Ensure that the "Start with current dwell times" checkbox remains unchecked unless you are refining an existing optimization. Starting with a fresh optimization typically produces better results for initial planning.

33. Configure Optimization Parameters

Click Add from clinical goals button (1)
Set Max (s) dwell time to 5-15 seconds (2)
Slide Smooth bar to MAX (3) to regulate dose distribution smoothness
Set the Max basal dose to 115% of the prescription dose to control maximum dose within the target (4)
Click Optimize, then OK
Inspect resulting dwell times (5) to ensure the distribution is reasonable (e.g., no large spikes showing long dwell times concentrated in a few positions)

34. Add Upper and Lower Objectives (Optional)

Optional Optimization Refinement

Adding upper and lower objectives can provide additional control over the dose distribution. This step is optional but may improve plan quality in certain cases.

Click the objectives icon in the optimization window
A dialog box will appear asking for the desired dose for normal tissue, pre-populated with the prescription dose
Click OK to accept the default value
In the objectives list, modify both upper and lower constraints:
- Set Volume [%] to 0
- Set Dose [%] to 100
- Set Priority to 400
The optimization constraints shown in the image above reflect these settings

3.4.3 Configure Isodose Levels

35. Set Standard Isodose Levels

Before dose shaping, configure the four standard isodose levels:

Navigate to isodose level settings (typically in the display or dose visualization menu)
Ensure exactly four levels are displayed: 200%, 115%, 100%, 50%
Verify line thicknesses: All isodose lines should have consistent thickness for clear visualization
Set color scheme and thickness:
- 200%: Yellow, 2
- 115%: Cyan, 2
- 100%: Red, 3
- 50%: Deep Blue, 2
These settings should be configured before proceeding to dose shaping

3.4.4 Dose Shaper Refinement

36. Adjust Dose Distribution with Dose Shaper

After initial optimization, use Dose Shaper tool to fine-tune dose distribution
Access via the icon on the tool bar or Planning > Modify Dose > Dose Shaper

Adjusting Dose Shaping Effect

For more localized control, right-click on a view (e.g., axial view) and slide the Dose shaping effect slider all the way to Local. This gives you finer control over dose sculpting in specific regions.

While holding Ctrl, click and drag isodose lines to manually sculpt dose around target
Focus on:
- Reducing hot spots in urethra and rectum
- Ensuring adequate target coverage
- Minimizing dose to bladder
Changes update dwell times in real-time
Click Calculate 3D Dose to see the impact of the dose on the Clinical Goals

Dose Shaper use case

Dose Shaper is particularly useful for addressing localized hot spots that automated optimization may not fully resolve, especially near critical structures like the urethra.

Changing Dose Per Fraction

If you need to change the dose per fraction value after optimization (e.g., you initially used the boost dose but meant to use monotherapy dose), BrachyVision will prompt you with a warning and automatically rescale the dwell times accordingly. This means you can correct the dose per fraction without re-optimizing from scratch—the system will proportionally adjust all dwell times to meet the new prescription.

Phase 4. Post-Planning Review and Approval

Physician Review

The physician will modify and finalize the dose distribution. The physician's final dose is what we use to proceed. We make changes as described below with the aim to not induce significant changes to the dose modified by the physician.

4.1 Review and Adjust Dwell Times

37. Inspect Dwell Time Distribution

Navigate to Window > Dwell Control Window
Inspect dwell times for each position in each applicator/needle to ensure values are acceptable (1)

38. Adjust Short Dwell Times

Review all dwell time values to ensure they are above 0.5 seconds
Make the following adjustments:
- Set dwell times ≤0.3 seconds to 0 (remove)
- Set dwell times of 0.4 seconds to 0.5 (minimum acceptable)
These modifications ensure reliable source positioning and delivery

39. Recalculate Dose

After making dwell time adjustments, click Calculate 3D Dose button (2)
Verify that clinical goals are still met
Ensure changes did not significantly alter the dose distribution
If clinical goals are no longer satisfied, make minor adjustments and recalculate

Quality Assurance

The main objective is to ensure that clinical goals remain met and do not change significantly after small modifications to dwell times. Once acceptable, proceed to Mobius verification.

4.2 Mobius Secondary Calculation

40. Create Mobius Reference Point

Move the axial plane to a central region of the target volume
Right-click Reference Points in the left panel
Select New Reference Point And Location
Click anywhere on the images in the right panel to place the point initially

41. Configure Reference Point Properties

In the properties dialog:
- Name: Mobius Fx1 (assuming first fraction)
- Type: Target
Click OK

42. Position the Calculation Point

Position the point on the 100% isodose surface
Place the point away from needle positions to ensure accurate dose calculation

Mobius Calculation Point Purpose

This reference point is used for independent dose calculation verification in Mobius. It should be positioned in a representative location within the target volume where dose can be reliably calculated and compared.

43. Export Plan to Mobius

Right-click plan name > Export > Mobius3D - Server 3
Click blue arrow > Authorize
Verify all files transferred successfully

Fraction count before export

Ensure number of fractions is set to 1 before export.

44. Access Mobius Report

In your browser, navigate to Mobius Server by typing the IP as your URL (e.g., 10.110.16.21)
Log in with credentials
Click patient name > Open PDF Report

45. Verify Agreement

Scroll to bottom of plan data
Confirm percent difference shows green checkmark (Mobius 2nd Check & Eclipse agree within tolerance)
Save report to P-drive as 4-mobius
- Navigate to P:\1. Methodist Dunn\3B. HDR Bravos Dunn\1. HDR Patient QA
- Create a folder using the patient's name if it doesn't exist
- Save the PDF in the patient's QA folder

Patient QA Folder Organization

Each patient should have a QA folder where you place files for each fraction, including:

Scanned template form from OR
Mobius calculation report
Other QA documentation as needed

46. Clean Up Eclipse Plan

Return to Eclipse plan
Delete Mobius Fx1 reference point before proceeding with plan approval

Reference Point Cleanup

Mobius point only needed for calculation documentation; removing improves screenshot clarity for final documents.

4.3 Plan Approval and Documentation

47. Approve HDR Plan

Right-click plan > Plan Approval > Planning Approved
Acknowledge minor warnings (unapproved/rejected structures)
Enter credentials for verification

Plan Approval Required Before Printing

The plan must be in Planning Approved status before generating treatment documents. During approval, you will need to specify the dose limits for the prostate reference point (target). Ensure these values are correctly entered as shown below:

48. Create Plan Report

File > Print > Report
Printer: Adobe PDF or Microsoft Print to PDF
Layout: BrachyFull.tml
Ensure the Layout in Properties is set to Portrait > Click OK
Save to patient path as 1-report

49. Create Orthogonal Views Screenshot (With Clinical Goals)

Double-click User Origin
Display Clinical Goals tab in bottom panel
File > Print > Screen
Properties > Layout: Change to Landscape
Click OK
Save to patient path as 2-iso-with-goals

50. Create Orthogonal Views Screenshot (Without Clinical Goals)

Hide Clinical Goals panel
Right-click top-right window > Select Show 3D View
Adjust 3D view to show a clear perspective of the needle arrangement
File > Print > Screen
Properties > Layout: Change to Landscape
Click OK
Save to patient path as 2-iso-3d-view

3D View Setup

The screenshot without clinical goals should showcase the 3D needle arrangement for physician review and documentation purposes. Ensure the view clearly displays the spatial relationship of needles relative to the target and critical structures.

51. Create DVH Report

Dose Statistics tab: Check all structures for DVH display
Click DVH panel (Above top-right or "3D" window)
Right-click > Print DVH Report
Ensure the Layout in Properties is set to Landscape > Click OK

DVH axis format

Ensure the DVH x-axis displays absolute dose (Gy) rather than percentage. This provides clearer clinical interpretation of the dose distribution.

Save to patient path as 3-dvh

52. Combine Documents

Select all files (1-report, 2-iso-with-goals, 2-iso-3d-view, 3-dvh, 4-mobius)
Right-click > Combine files in Acrobat
Save combined PDF in patient folder

53. Upload Combined Plan Document

In Aria, use the Import button (not the New button )
Select the combined PDF created in step 52
Set the template name to:
- HDR Prostate Fx1 (or Fx2) for monotherapy fractions
- HDR Prostate Boost for boost treatments

Import vs New Button

The Import button is used for uploading existing documents (like your combined PDF), while the New button creates new documents from templates. Always use Import for the combined plan document.

54. Create Special Physics Consultation

Click the New button
Select template: HDR Prostate Consult
Complete the required fields:
- Number of needles implanted: Total needles placed during the procedure
- Number of needles used: Needles included in the final treatment plan
- D90 value: The dose covering 90% of the target volume (from clinical goals)

55. Create Tx Plan HDR Note

Click the New button
Select template: Tx Plan HDR Note
Complete the required fields:
- Number of channels (needles): Enter the number of needles used in the plan
- Number of dosimetry calculations: Enter 1 (corresponds to the single Mobius secondary calculation)