Program Information
MR Safety Assessment of a Novel Prototype DMBT Tandem Applicator at 3T for HDR Cervical Cancer Brachytherapy
A Soliman1,2*, S Davidson3, W Song1,2,4 , (1) Sunnybrook Research Institute, Toronto, ON, (2) Medical Physics, Sunnybrook Health Sciences Centre,Toronto, ON, (3) Techna Institute, University Health Network, Toronto, ON, (4) Radiation Oncology, University of Toronto, Toronto, ON
Presentations
MO-L-GePD-IT-2 (Monday, July 31, 2017) 1:15 PM - 1:45 PM Room: Imaging ePoster Theater
Purpose: To monitor the temperature induced by a novel prototype direction modulated brachytherapy (DMBT) tandem applicator at 3T in clinical settings.
Methods: The tandem applicator was placed in a plastic container filled with a conductivity-mimicking solution consisting of 7g/L NaCl dissolved in 8L of water. This concentration is assumed to represent tissue with high conductivity. The phantom was scanned on a 3T Philips Achieva with the body coil as transmit coil. A fiberoptic thermometer (LumaSense® Technologies Inc.) was used to monitor the temperature during the scan. The tandem is composed of three connected parts, a PEEK tip, a tungsten alloy in which 6 channels for the sources are grooved, and a brass handle. The whole tandem was coated with ~0.3mm of FEP plastic, on which three temperatures probes were taped at the tip of the tandem, the tungsten alloy and the brass handle, respectively. A fourth probe was placed inside the solution to measure the ambient temperature rise. Three clinical 2D fast-spin echo sequences (coronal, sagittal and axial) were applied in addition to a 3D FSE sequence. The number of averages was increased to achieve a total scan time of approximately 75 minutes. The temperature was recorded before, during and after the scan.
Results: Neither displacement nor torque from the tandem were observed during the experiment. The baseline temperature was 24.6±0.07, 24.5±0.06, 24.0±0.06 and 25.1±0.07 ᵒC at the PEEK tip, tungsten alloy, brass and in the solution, respectively. Maximum temperature rise occurred during the scan and recorded an increase of 0.5, 0.4, 0.3 and 0.4 ᵒC, respectively, over baseline. It is worth noting that all peak temperature rise occurred during the 3D FSE acquisition.
Conclusion: The tungsten-based DMBT tandem applicator did not exhibit significant temperature rise at 3T during and after long exposure to RF pulses from clinical FSE sequences.
Contact Email: