Accurate, repeatable, and geometrically precise diffusion-weighted imaging on a 0.35 T magnetic resonance imaging-guided linear accelerator.

Autor:	Weygand J; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA., Armstrong T; ViewRay Inc., Cleveland, OH, USA., Bryant JM; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA., Andreozzi JM; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA., Oraiqat IM; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA., Nichols S; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA., Liveringhouse CL; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA., Latifi K; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA., Yamoah K; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA., Costello JR; Department of Radiology, Moffitt Cancer Center, Tampa, FL, USA., Frakes JM; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA., Moros EG; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA., El Naqa IM; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA.; Department of Machine Learning, Moffitt Cancer Center, Tampa, FL, USA., Naghavi AO; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA., Rosenberg SA; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA., Redler G; Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA.
Jazyk:	angličtina
Zdroj:	Physics and imaging in radiation oncology [Phys Imaging Radiat Oncol] 2023 Nov 08; Vol. 28, pp. 100505. Date of Electronic Publication: 2023 Nov 08 (Print Publication: 2023).
DOI:	10.1016/j.phro.2023.100505
Abstrakt:	Background and Purpose: Diffusion weighted imaging (DWI) allows for the interrogation of tissue cellularity, which is a surrogate for cellular proliferation. Previous attempts to incorporate DWI into the workflow of a 0.35 T MR-linac (MRL) have lacked quantitative accuracy. In this study, accuracy, repeatability, and geometric precision of apparent diffusion coefficient (ADC) maps produced using an echo planar imaging (EPI)-based DWI protocol on the MRL system is illustrated, and in vivo potential for longitudinal patient imaging is demonstrated. Materials and Methods: Accuracy and repeatability were assessed by measuring ADC values in a diffusion phantom at three timepoints and comparing to reference ADC values. System-dependent geometric distortion was quantified by measuring the distance between 93 pairs of phantom features on ADC maps acquired on a 0.35 T MRL and a 3.0 T diagnostic scanner and comparing to spatially precise CT images. Additionally, for five sarcoma patients receiving radiotherapy on the MRL, same-day in vivo ADC maps were acquired on both systems, one of which at multiple timepoints. Results: Phantom ADC quantification was accurate on the 0.35 T MRL with significant discrepancies only seen at high ADC. Average geometric distortions were 0.35 (±0.02) mm and 0.85 (±0.02) mm in the central slice and 0.66 (±0.04) mm and 2.14 (±0.07) mm at 5.4 cm off-center for the MRL and diagnostic system, respectively. In the sarcoma patients, a mean pretreatment ADC of 910x10 -6 (±100x10 -6 ) mm 2 /s was measured on the MRL. Conclusions: The acquisition of accurate, repeatable, and geometrically precise ADC maps is possible at 0.35 T with an EPI approach. Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: JW, the first and corresponding author, has nothing to declare. Amongst the coauthors, TA was an employee of ViewRay, Inc at the time this work was performed and owned ViewRay, Inc stocks at that time. EGM, JMF, and SAR have been supported by a grant/contract from ViewRay, Inc. KL and SAR have consulted for ViewRay, Inc. (© 2023 The Author(s).)
Databáze:	MEDLINE
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