Medical Physics Seminar – Monday, April 10, 2023
Assessment of Fetal Arrhythmias via Simultaneous Fetal Echocardiography and Fetal Magnetocardiography
Tan Phan
Graduate Research Assistant
There is currently no comprehensive method to assess heart rhythm and function in utero. Postnatally, electrocardiography (ECG) and echocardiography are recorded simultaneously to obtain electrical and mechanical information; however, fetal ECG is unreliable prenatally. Fetal magnetocardiography (fMCG) is an effective technique for evaluating fetal arrhythmias but cannot assess mechanical function and requires magnetic shielding. Conversely, fetal echocardiography (fEcho) cannot directly assess electrical conduction issues. This work demonstrates the advantages of optically pumped magnetometers (OPMs) for simultaneous fMCG and fEcho. A person-sized magnetic shield was modified to allow a sonographer to scan inside the shield while the OPM sensors remained shielded from the ultrasound scanner interference. Signal post-processing of the fMCG was performed to remove maternal and environmental interference. The fMCG was time-aligned with the fEcho with a timing signal. The combined fMCG-fEcho technique allows for direct comparison between the magnetic and mechanical fetal rhythms and allows for assessment of fetal electromechanical function.
Development and Testing of a Dosimeter Compatible SPECT/CT Phantom for Beta Emitting Radiopharmaceutical Therapy Agents
Andrew Bertinetti
Graduate Research Assistant
Radiopharmaceutical therapy (RPT) is a rapidly growing field of radiation therapy capable of delivering localized doses of radiation in a systemic fashion and is currently used in the treatment of numerous cancers ranging from neuroendocrine tumors and pheochromocytomas to non Hodgkins lymphoma and castrate-resistant prostate cancer.
Most current forms of radiation therapy (RT) have well-defined dosimetry protocols utilizing detectors with NIST-traceable calibrations to absorbed dose to water. While advancements in imaging and computational efficiency have improved personalized RPT dosimetry through Monte Carlo (MC) based techniques, performing measurements on liquid solutions of RPT agents with common RT detectors remains challenging. This work aims to design, construct, and test a SPECT/CT phantom compatible with multiple active detectors and passive dosimeters to compare dosimetric measurements of beta-emitting RPT radionuclides in solution to MC based dosimetry estimates.