Preliminary results on the feasibility of using ultrasound to monitor intrafractional motion during radiation therapy for pancreatic cancer

Abstract

Large intrafractional organ motion due to respiratory and/or bowel motion is a limiting factor in administering curative radiation doses to pancreatic tumors. The authors investigate the use of real-time ultrasound to track pancreas motion. Due to the poor visibility of the pancreas head on an ultrasound image, the portal vein is identified as a surrogate. The authors have demonstrated the feasibility of tracking HP motion through the localization of the PV using TAUS. This will potentially allow real-time tracking of intrafractional motion to justify small PTV-margins and to account for unusual motions, thus, improving normal tissue sparing.

Evaluation of the intra‐ and interfractional tumor motion and variability by fiducial‐based real‐time tracking in liver stereotactic body radiation therapy

“…Recently, real‐time observation of tumor movement during treatment is becoming more common,16, 17 and new apparatuses integrating this function are gradually being used by clinical facilities 18, 19. CyberKnife is the earliest commercial device for real‐time monitoring and tracking.…”

A Monte Carlo study of the effect of an ultrasound transducer on surface dose during intrafraction motion imaging for external beam radiation therapy

“…For the transperineal imaging configuration, it is assumed that all beam angles in the treatment plans avoid the probe . The Autoscan probe could also be used in a transabdominal imaging configuration, where treatment would need to be planned incorporating the attenuation and scattering from the probe …”

“…13 The Autoscan probe could also be used in a transabdominal imaging configuration, where treatment would need to be planned incorporating the attenuation and scattering from the probe. 14…”

Ionizing radiation‐induced acoustics for radiotherapy and diagnostic radiology applications

“…The integration of XACT into the clinical workflow will be aided by developments in intrafractional ultrasound imaging since many of the challenges arising from placing a transducer in contact with the patient during radiotherapy delivery have already been investigated in the literature. Intrafractional ultrasound imaging has been clinically demonstrated for tracking the target during prostate, liver and pancreas treatments. Due to the same requirements for acoustic wave propagation for both XACT and diagnostic ultrasound, XACT is expected to be applicable to the same clinical sites that are accessible by diagnostic ultrasound, namely the breast, liver, kidney, pancreas, prostate, cervix, uterus, bladder, and rectum …”