Principles and Practice of Electronic Brachytherapy Jessica Hiatt - PowerPoint PPT Presentation

Principles and Practice of Electronic Brachytherapy Jessica Hiatt MS IAEA ICARO, Vienna, Austria April 27, 2009

Brachytherapy: • Internal radiation therapy that involves placing radioactive sources inside the patient close to or in the tumor.

Electronic Brachytherapy: • Internal radiation therapy that involves placing a miniature x-ray source inside the patient close to or in the tumor.

HV Cable X-Ray Tube Xoft Tube (2006)

XOFT Axxent Electronic Brachytherapy System: Source Controller Applicators

X-ray Source • Tube diameter = 2.25 mm • Requires a cooling catheter – Assembly diameter = 5.4 mm • Nominal dose rate: – 0.6 Gy/min at 3 cm in water

Comparison of Dose Rate vs. Depth in Water for Various Sources 1.E+03 50 kV 1.E+02 50 kV MCNP5 Pd 103 I 125 1.E+01 Ir 192 Dose Rate (cGy/min) 1.E+00 1.E-01 1.E-02 1.E-03 1.E-04 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Radius (cm) Dose rate curve is quite similar to 192 Ir over region of interest Graph courtesy of Xoft

Axxent Controller: Touch Screen Display Controller Pullback Arm Barcode Reader USB Port Well Chamber SI Max 4000 Electrometer

Breast Applicator: Balloon Inflation NO CONTRAST!! Valve Drainage Holes Radiation Source Lumen Drainage Port Valves

Intracavity APBI: MammoSite HDR 192 Ir Xoft 50kV Dickler et al. Brachytherapy , 2007

Vaginal Applicator Set: • FDA clearance in May 2008 • Available in four diameters – 20, 25, 30 and 35 mm • Each set contains four vaginal cylinders, four source channels and a board & clamp assembly • Enhanced visibility with CT and fluoroscopic imaging

Vaginal Cylinder: EB IB

EB for Skin: • Applicator sizes: – 10, 20, 35, and 50 mm • Circular • Stainless steel • Flattening filter integrated in cone Scalp treatment with Leipzig applicator Images provided by Xoft

Advantages of EB: • Minimal shielding required • Capabilities for IORT • Can easily be turned ON/OFF • No isotope handling burden

AAPM TG-182 Recommendations on Electronic Brachytherapy Quality Management Chair: Bruce Thomadsen Axxent IntraBeam Clinical Michael Ringor Gene Cardarelli Chris Stacey Mark Rivard Jessica Hiatt Vendor/Vendor Frank Weigand Randall Holt Clinical Ben Smith Calibration/QA Tina Pike Larry DeWerd

EB Conclusions: • EB has many advantages over isotope-based brachytherapy • EB offers the potential to profoundly impact brachytherapy practice • EB QA procedures need to be defined • Clinical studies are necessary to prove EB’s efficacy