This document provides an agenda and information for a breast IORT symposium. The agenda includes presentations on IORT and Xoft system physics, as well as experience using IORT at two hospitals. Statistics on breast cancer incidence and treatment in the US are presented showing that over 20% of potential lumpectomy patients do not receive radiation therapy. The Xoft Axxent electronic brachytherapy system is introduced as a solution for delivering IORT using a miniaturized x-ray source in applicators. Physics details include comparable dose profiles to radioactive sources and rapid dose fall-off away from the applicator.

1. Welcome to the
Breast IORT Symposium
Clinical and Practice Perspectives

2. Agenda
6:00 – 6:10 Introduction D. Francescatti, MD
Xoft System Overview
6:10 – 6:20 IORT/Xoft System Physics R. Holt, PhD
6:20 – 7:00 IORT Experience at M. Silverstein, MD
Hoag Hospital
7:00 – 7:30 IORT Experience at B. Schwartzberg, MD
Rose Medical Center
7:30 – 7:45 IORT Reimbursement K. Francisco, Pinnacle
Health Group
7:45 – 8:00 Discussion

3. Intraoperative Radiation Therapy (IORT)
Radiation Therapy at the Time of Lumpectomy

4. Breast Cancer: Radiation Therapy Advancement
6 - 7 weeks
of treatment
5 days
twice a day
As little as 8 min.
during surgery
WBRT APBI IORT
1950 - Present 1992 - Present 2000 - Future
MC418R1 4/12

5. Breast Cancer
U.S. Incidence
MC418R1 4/12

6. (1)Combined New Invasive, DCIS, LCIS and Regional (2)Combined localized 60% of DCIS patients with unicentric disease
Sources: American Cancer Society; Cancer Facts and Figures 2010 NIH, SEER Incidence Data, 2007. BCT = Breast Conserving Therapy
Lumpectomy
w/ RT
43%
Lumpectomy
w/o RT
20%
Mastectomy
w/o RT
37%
Localized Stage
54%
Regional or
Distant Stage
25%
DCIS
18%
LCIS
3%
Breast Cancer Statistics – U.S.
Breast Cancer Cases Eligible for Lumpectomy
261,100 Cases 168,000 Eligible Patients
>20% of Potential BCT Patients
NEVER
Receive Radiation Therapy

7. 0%
10%
20%
30%
40%
50%
60%
≤10 10 to 25 25 to 50 >50
Miles from RT Facility
*Impact of Patient Distance to Radiation Therapy on Mastectomy Use in Early Stage Breast Cancer Patients, A.
Schroen et al., Journal of Clinical Oncology, October 1, 2005
% Patients
Opting for
Mastectomy
Mastectomies increase almost 50% for patients living
more than 50 miles from radiation therapy center
Socioeconomic Factors
MC418R1 4/12

8. **Journal of National Cancer Institute, February 2, 2000 New Mexico Statistics following Breast Conserving Surgery
Socioeconomic Factors
Distance to Radiation Therapy Reduces Patient Compliance
30%
40%
50%
60%
70%
80%
90%
<10 10-24 25-49 50-75 75-100 >100
% of Patients
Receiving
Radiation
Therapy
Miles Patient Travelled

9. Xoft Axxent®
eBx®
System

10. Xoft Axxent®
eBx®
System
A Platform and System of Care
 REST OF BODY
 BREAST

11. Miniaturized X-ray Tube
The Electronic Brachytherapy Source
The Source Operates
at 50 kV and 300
microamps
(15 Watts)

12. One System. Multiple Solutions
The Xoft Axxent®
Controller is FDA cleared
for use anywhere in the body

13. Display Screen/
Touch Screen
Control
Well Chamber
Handheld
Barcode
Scanner
Adjustable arm
(in storage
position)
Wheel Brakes
Xoft Axxent®
eBx ®
Controller Components

14. Controller Components
Applicator
hub
attachment
Source
connected
to source nest
Source high voltage
cable attachment

15. Balloon Inflation Valve
Drainage Port Valve
Drainage Holes x 7
Balloon Applicator
Drainage holes
• Seroma management -
potentially reduce infection
• Improve dosimetry
Radiolucent Balloon Wall for
improved visibility while imaging
Sizes:
3-4 cm spherical
4-5 cm spherical
5-6 cm spherical
5x7 cm ellipsoidal

16. Treatment Times for 20 Gy to Surface are 2 - 2.5X Faster with Xoft
Xoft data computed for all balloons by Pacific Crest Medical Physics, May 2010. Plans were optimized to deliver 20 Gy to the surface using TG-43 data on BrachyVision
from CT scans of all possible balloon sizes and including a 6% latex wall BaSO4 correction.
40 uA Tx time data and median diameter used in IORT comes from “IORT for Breast Cancer using the Intrabeam system”, Tumori, 91: 339-345, Kraus-
Tiefenbacher, et al
Balloon Diam.
(cm) *
Xoft 300 µA source (min) 40 µA source (min)
3.0 4.9 24.9
3.5 7.6 18.6
4.0 10.9 26.8
4.5 15.2 36.6
5.0 20.3 48.9
Median (4.2) 12.5 32.4
More Efficient Operating Room - Faster Turnover

17. Benefits of Selecting Xoft
• Economical
• Mobile
• Versatile - platform technology
• Treat area at greatest risk of tumor recurrence
• Less time in the OR
• Convenient for patient
• Green technology/isotope free

18. Xoft Axxent ®
eBx ®
System
Physics

19. Xoft Miniaturized X-ray Source
 Fully disposable device
 Rapid treatment times
Miniaturized X-ray Source:
Detailed View
Miniaturized X-ray Source
Cooling
connections
HV connection
X-ray Tube HV Cable

20. Radiation Safety: Time, Distance, Shielding
Distance 1 meter 2 meters
Shielding none
1 mm rolling
shield
none
1 mm rolling
shield
C-arm OR
Fluoroscopy
(50 – 120 kV)
120 mR/hr 0.32 mR/hr 30 mR/hr 0.08 mR/hr
50 kV source
w/FlexiShield
15 mR/hr 0.04 mR/hr 3.8 mR/hr 0.01 mR/hr
Radiation Safety

21. TG43 formalism accurately represents the actual source characteristics
34 Red
17 Orange
10.2 Yellow
6.8 Green
5.1 Blue
3.4 Dark Blue
1.7 Magenta
Film 40A01
D (Gy)
34 Red
17 Orange
10.2 Yellow
6.8 Green
5.1 Blue
3.4 Dark Blue
1.7 Magenta
Film 40A01
34 Red
17 Orange
10.2 Yellow
6.8 Green
5.1 Blue
3.4 Dark Blue
1.7 Magenta
Film 40A01
D (Gy)
34 Red
17 Orange
10.2 Yellow
6.8 Green
5.1 Blue
3.4 Dark Blue
1.7 Magenta
40 kV Probe in
BrachyVision®
D (Gy)
34 Red
17 Orange
10.2 Yellow
6.8 Green
5.1 Blue
3.4 Dark Blue
1.7 Magenta
 X-ray distribution described mathematically in AAPM TG-43 format
 Film measurements compare parameterization to actual
X-ray Source Distribution Pattern
X-ray Distribution On Film
Predicted Distribution From Planning System

22.  Same dose as Iridium-
192 at the prescription
point
 Higher dose inside
applicator (absorbed by
saline)
 Rapid dose fall off
requires less shielding
Xoft eBx®
Radiation
Depth-dose curve similar to 192Ir over region of interest
Illustrated for 5 cm diameter applicator

23. High Dose, Low Energy Delivers Less
Radiation to Critical Structures (heart, lung, ribs)
Dickler, et al. “A dosimetric comparison of MammoSite high dose rate brachytherapy and Xoft Axxent electronic brachytherapy,”
Brachytherapy (6) 2007, 164-168.. Slide courtesy of Dr. David Wazer

24. Dose shaping capabilities: Not limited to spherical applicators
• Multiple dwell points allow optimal dose to be shaped as needed
• Typical planning method
– Pre-planned Atlas for all possible balloons, pre-validated by physics
– Appropriate plan chosen during surgery
IORT Dose Shaping Capabilities:
Spherical and Ellipsoidal Applicators
6 cm long x 4 cm ellipsoidal4 cm spherical

25. Dose-Volume Histogram (DVH) Comparison of
IORT Plans for Two 50 kV Systems
1. Nairz O, et al. “A dosimetric comparison of IORT techniques in limited-stage breast cancer”. Strahlenther Onkol 2006. 182: 342-348
Intrabeam DVH of PTV: from Nairz
Xoft DVH of PTV, plan A: optimized to match Nairz
Xoft DVH, plan B: opt. to maximize 1 cm dose
PTV = CTV+1 cm
CTV = 4 cm
diameter sphere,
with lumen

26. Energy Spectra of 50 kV Tungsten and Gold X-rays
0
50
100
150
200
250
300
0
500
1000
1500
2000
2500
0 10 20 30 40 50 60
After 2 cm Water Filtration
Xoft Nist
Amptex Au50
0
2000
4000
6000
8000
10000
0 10 20 30 40 50 60
Xoft Tungsten
0cm
1cm
2cm
3cm
4cm
0
200
400
600
800
1000
1200
1400
0 20 40 60
Amptek Au
0cm
1cm
2cm
3cm
4cm
Energy (kV)
Counts(arbitrary)
Counts(arbitrary)
Energy (kV)
Energy (kV)