The SAVI TM Applicator: Breast Brachytherapy Training

Transcription

1 The SAVI TM Applicator: Breast Brachytherapy Training

2 SAVI Breast Brachytherapy Greater flexibility Treats the widest array of cavity & breast sizes Enhanced performance Eliminates skin spacing restrictions Better outcomes Lowers toxicity & risk of persistent seroma Exceptional precision Sculpt dose with selective radiation Added convenience Simple, secure placement and removal

3 SAVI Product Line SAVI Applicator 6-1Mini SAVI Prep Catheter

4 SAVI Applicator Details

5 Ideal SAVI Procedure Flow Chart Pre-Implant CT Evaluation SAVI Implanted CT Simulation Treatment Planning Pre-Fraction QA and Treatment Delivery

6 SAVI Procedures Pre-Implant CT Evaluation

7 Pre-Implant CT Evaluation (w/o SPC) Performed 72 hours prior to implant 1. Obtain CT scan of breast to be treated - 3 mm slices - no gaps between slices - Patient arms up or down - Scan with breath hold if possible - Scan 2 cm superiorly and inferiorly beyond the cavity - Send CT data set to planning software 2. Have MD evaluate cavity and record data - Outline cavity margins on axial images - Determine volume (cc) of cavity - Measure the long axis (cm) and short axis (cm) - Assess the best insertion site and entry angle

8 Pre-Implant CT Evaluation 4. Using that data, determine the most appropriate SAVI applicator size using the SAVI Size Reference Chart 5. Communicate SAVI size and cavity/insertion parameters to SAVI Representative and the Physician who will implant SAVI

9 SAVI Size Reference Chart

10 Size Reference Chart

11 SAVI Procedures CT Simulation

12 CT Simulation of SAVI Implant CT Simulation is performed hours post-implant When patient arrives for the CT simulation: 1. Ask the patient for the expansion tool (surgeon should have given it to her). 2. Create an immobilization device. (e.g. Vac-Lock, alpha cradle) 3. Position patient on CT scanner and remove bandages. Patient should be supine Arms can be; above head (typical), akimbo or by her sides (if more comfortable)

13 CT Simulation of SAVI Implant 4. Place CT laser alignment marks on patient and immobilization device (for repositioning). 5. Remove the Catheter Protector from catheter #1 Insert expansion tool over catheter #1 Place in safe location to avoid damage and loss (e.g., emesis basin) The expansion tool is used for each fraction, thus insertion for planning CT provides more exact reproduction of treatment setup. Optional step: Insert a marker wire into catheter #1 (this will help identify its physical end) 6. Acquire AP and lateral scouts (print or save)

14 CT Simulation of SAVI Implant 7. Acquire planning CT data set: Use contiguous slices (e.g., no gaps) mm slice thickness Planning position must be used for treatment! Scan 2 cm superiorly and inferiorly beyond the cavity (or whole breast) 8. Evaluate implant in all three planes on CT console 9. If significant air pockets are present the device should be collapsed by the physician (left in situ), the air pockets massaged out and the device re-expanded and the CT repeated. 10. Remove expansion tool & marker wire from the SAVI (if used) 11. Replace the Catheter Protector in catheter #1

15 CT Simulation of SAVI Implant 12. Measure and record* distance from skin surface to catheter handle or use the scale on catheter 1 (depth assessment) 13. Mark white ring and skin in continuous line and fill in the "clock" diagram of the SAVI template provided (rotational assessment) *Record measurement on SAVI Prescription and Treatment Summary Template

16 CT Simulation of SAVI Implant 14. Attach transfer guide tubes & measure the catheter lengths and record. (this length is NOT the treatment length) VariSource expected treatment lengths (not measured lengths) #1 length: to cm All others: to cm GammaMed lengths should be checked with the Acceptance Length wire. 15. Retain the AP & lateral scouts as reference images for pre-fraction evaluation 16. Export CT to Treatment Planning Software

17 SAVI Procedures Treatment Planning

18 Treatment Planning Contouring anatomy Identifying applicators Dose prescription and optimization DVH & Isodose Analysis

19 Contouring Anatomy Create new body structures. Consider a structure template for efficiency. SAVI = this will be the margin of the cavity in all slices PTV_Opt = this will be a 1.0 cm positive expansion of the Cavity (short for PTV for Optimization) Body = this is the surface of the skin Lung = lung-chest wall interface Chest = this surface is defined as the chest wall or pectoralis PTV_Eval = PTV_Opt minus SAVI. Also subtract Body, Lung and/or Chest as needed Other structures as needed: Cavity for air or seroma pockets outside SAVI Invag for tissue invaginating into the SAVI per MD choice

20 Case A Slice 12 Slice 15 Slice 17 Slice 22 Slice 25

21 Creating Planning Structures Create the SAVI structure using the convert isodose to structure Define PTV_Opt as 1-cm expansion of SAVI, minus Portion of expansion outside Body or Skin Portion of expansion extending into Chest and/or Lung Contour air & seroma pockets outside SAVI Name nonconforming pockets Cavity Apply 10% nonconformance rule, or Add Cavity to SAVI & redo 1-cm expansion Contour invaginated tissue PTV_Eval = PTV_Opt minus SAVI plus Invag The order of Boolean operations above is critical!

22 Contouring SAVI another way Utilize the Brush set options to 3D and Static 22

23 Draw the structure in either the Sag or Coronal view initial brush Diam 6 mm-6-1, 8 mm-8-1, & 10mm

24 24

25 Post Processing smooting level 3 - Before After 25

26 Invaginated Tissue

27 Identifying Catheters Use MPR to rotate the views until the axis of the applicator is seen clearly in 2 orthogonal views. The third view should be a head-on view of the applicator. Move through the stack of images in the head-on view from the applicator s most distal tip to the proximal end where the struts rejoin the central lumen.

28 Catheter 1 Central Lumen Catheter 1 was defined already must check that it starts in correct location Move to one of the views showing the full length of the applicator. The distal tip of #1 should be ~1.3 cm beyond the bright metal band. The final (proximal) point of #1 should be at least 1 cm past the point where the proximal ends of the struts rejoin the central channel.

29 Catheter 2, etc. Go to the head-on view window and determine which catheter is #2. Rotate the images in this window until catheter #2 is visualized fully in one of the orthogonal view windows Turn on PTV structure Insert Catheter2 defining the distal tip ~0.5 cm past the distal end of the bright band Continue to define Catheter2 in the orthogonal view that best shows the source channel Draw the applicator outside the strut Catheter3 is easiest found after locating Catheter4 which has the equatorial marker. Use the head-on view. This establishes the rotational orientation for remaining struts

30 Find Catheter 4 by adjusting Axis 30

31 Rotate to Catheter 4 31

32 Rotate to Catheter 2 32

33 Measure distance to 1 st catheter 11.3mm 33

34 Move back ruler to 2.9mm and insert 1 st catheter 34

35 Move axis to ruler (2.9mm) and insert 2 reference lines on axis to mark start of delineation of peripheral catheters 35

36 Insert Catheter 2 36

37 Catheter 4 as drawn Catheter 4 as drawn Catheter 6 37

38 Source Lumens

39 Setting dwell positions Dwell positions can be set by: Manually setting start and end lengths Populating dwells inside a structure (i.e., the PTV-Opt, not the PTV-Eval) Recall that Catheter1 already has dwell times Reset all dwells to zero otherwise optimizer will start with heavy center channel loading. This will reduce your ability to modulate dose later by limiting dwells in peripheral catheters.

40 Loading Dwells Fill dwells inside PTV ONLY 40

41 Optimize Dose 41

42 Dose prescription and optimization Rx is 3.4 Gy/fx to surface of PTV_Opt (chose surface option in volume optimization window of BV) Add objective to PTV-Opt for 100% +/- 5% (e.g., 3.4 Gy +/ Gy) Dose optimization goals are as follows: PTV_Eval; 95% of volume receives 95% of prescribed dose PTV_Eval receiving 200% of dose must be < 20 cc PTV_Eval receiving 150% of dose must be < 50 cc Skin and chest wall limits met Evaluate DVH of the optimized plan Review DVH for clinical adequacy with MD With MD input, manually optimize dose to skin & chest wall Perform second check After approval by physician, follow standard operating and QA procedures for recording, documenting and exporting plan to HDR afterloader

43 Planned Case

44 DVH Analysis Comparison V90 V95 Interstitial (RTOG B-39) MammoSite (RTOG B-39) SAVI Ø 90% > 90% >90% >95% V cc 50 cc 50 cc V cc 10 cc 20 cc

45 SAVI Procedure Pre-Fraction QA and Treatment Delivery

46 Pre-Fraction QA 1. Remove all dressings 2. Position patient on CT table to match original positioning 3. Align marks on patient with CT simulator lasers 4. Measure distance from skin to central channel handle a. Compare to reference value taken at planning CT 5. Check for rotation 6. Record data on SAVI Prescription and Treatment Summary Template 6-1 and 6-1 Mini

47 Pre-Fraction QA 7. Acquire AP and lateral scouts and axial images 8. Evaluate scouts for movement or rotation of SAVI by measuring the 2, 4 and 6 markers with respect to patient anatomy. 9. If changes are noted notify Physician to re-plan/ reposition device if needed

48 Accessing Rotation How to access Rotation Look for major differences between the relative positions of the markers - AP Scouts 48

49 Accessing Rotation How to access Rotation Look for major differences between the relative positions of the markers L Lat Scouts 49

50 Scouts: Baseline & Fraction 1 Laterals Patient setup assessment Black: gap between tip and sternum is ~10 mm Patient setup assessment Black: gap between tip and sternum is ~6-7 mm (close setup) Device assessment Red: #2 is almost on center Blue: #4 at outer edge of device Yellow: 2 center have ~ 4mm gap Green: #6 is slightly inside an outer strut Fx1 Device assessment Red: #2 is almost on center (same) Blue: #4 at outer edge of device (same) Yellow: 2 center have ~ 3mm gap Green: #6 is slightly inside an outer strut (almost same)

51 Scouts: Baseline & Fraction 1 AP Scouts Patient setup assessment Red: distal tip at lateral edge of ribs Green: #2 is at center of ribs Patient setup assessment Red: distal tip in middle of ribs (slight setup difference) Green: #2 is at inner edge of ribs (slight setup difference) Device assessment Blue: #4 slightly inside the outer edge of device Yellow: #6 outer edge and ~1mm from touching center Green: #2 is at outer edge of device Device assessment Blue: #4 at outer edge of device (very slight difference) Yellow: #6 outer edge and almost touching center (very slight difference) Green: #2 is at outer edge of device (same) Impression: Patient setup shows slight rotation, right-side slightly towards posterior. SAVI appears almost perfectly reproduced in AP & laterals. Slight changes in SAVI markers consistent with slight changes in patient rotation, not SAVI rotation.

52 HDR Fraction Delivery 1. In the HDR suite, position patient as for the CT Simulation 2. Remove the Catheter Protectors and store in safe location 3. Insert the Expansion Tool over the center catheter until properly engaged into the fitting of the SAVI applicator (NOTE: important for potential emergency response) 3. Obtain requisite number of transfer tubes SAVI 6-1 requires seven transfer tubes (#1-7) SAVI 8-1 requires nine transfer tubes (#1-9) SAVI 10-1 requires eleven transfer tubes (#1-11) 4. Insert proximal end of SAVI catheter #1 into the catheter connector on the distal end of transfer tube #1 5. Insert the proximal end of transfer tube #1 into the HDR unit turret s #1 opening.

53 HDR Fraction Delivery 6. Repeat step 5 until all transfer guide tubes are connected 7. Double-check the connection numbers of the SAVI applicator, transfer guide tubes and at the turret. 8. Reposition HDR unit to maintain straightness of transfer guide tubes (as much as possible) 9. Verify each transfer guide tube connection is connected properly, and that indexer is locked

54 HDR Fraction Delivery 10. Follow SOPs for fraction delivery 11. Disconnect patient from HDR unit, disconnect transfer guide tubes from SAVI 12. Insert purple Catheter Protectors. 13. Re-bandage or dress the SAVI-skin entrance site using standard techniques

55 Inverted Strut

56 Inverted Strut Inverted Strut

57 Inverted Strut - Planned

58 Thank you!