Quantitative Imaging in Radiation Oncology: An Emerging Science and Clinical Service

Jaffray, David A.; Chung, Caroline; Coolens, Catherine; Foltz, Warren D.; Keller, Harald; Ménard, Cynthia; Milosevic, Michael; Publicover, Julia; Yeung, Ivan

doi:10.1016/j.semradonc.2015.05.002

Cited by 17 publications

(10 citation statements)

References 108 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Among qMRI techniques, functional imaging can play a relevant role in MR-guided workflows [77] and its use complemented with that of anatomical acquisition is being explored to provide multi-parametric analyses [78,79]. Specifically for functional qMRI protocols, dynamic contrast enhanced and diffusion weighted MRI have been widely explored [80][81][82] due to their sensitivity to vasculature architecture [83] and tissue structure [76,84], respectively. These sequences could improve any stage of the radiotherapy workflow [75,85,86]: from diagnosis and patient stratification [87,88], through contouring and dose optimization [89,90], to treatment monitoring and response assessment [83,91,92].…”

Section: Quantitative Imagingmentioning

confidence: 99%

Medical physics challenges in clinical MR-guided radiotherapy

et al. 2020

View full text Add to dashboard Cite

The integration of magnetic resonance imaging (MRI) for guidance in external beam radiotherapy has faced significant research and development efforts in recent years. The current availability of linear accelerators with an embedded MRI unit, providing volumetric imaging at excellent soft tissue contrast, is expected to provide novel possibilities in the implementation of image-guided adaptive radiotherapy (IGART) protocols. This study reviews open medical physics issues in MR-guided radiotherapy (MRgRT) implementation, with a focus on current approaches and on the potential for innovation in IGART. Daily imaging in MRgRT provides the ability to visualize the static anatomy, to capture internal tumor motion and to extract quantitative image features for treatment verification and monitoring. Those capabilities enable the use of treatment adaptation, with potential benefits in terms of personalized medicine. The use of online MRI requires dedicated efforts to perform accurate dose measurements and calculations, due to the presence of magnetic fields. Likewise, MRgRT requires dedicated quality assurance (QA) protocols for safe clinical implementation. Reaction to anatomical changes in MRgRT, as visualized on daily images, demands for treatment adaptation concepts, with stringent requirements in terms of fast and accurate validation before the treatment fraction can be delivered. This entails specific challenges in terms of treatment workflow optimization, QA, and verification of the expected delivered dose while the patient is in treatment position. Those challenges require specialized medical physics developments towards the aim of fully exploiting MRI capabilities. Conversely, the use of MRgRT allows for higher confidence in tumor targeting and organs-at-risk (OAR) sparing. The systematic use of MRgRT brings the possibility of leveraging IGART methods for the optimization of tumor targeting and quantitative treatment verification. Although several challenges exist, the intrinsic benefits of MRgRT will provide a deeper understanding of dose delivery effects on an individual basis, with the potential for further treatment personalization.

show abstract

Section: Quantitative Imagingmentioning

confidence: 99%

Medical physics challenges in clinical MR-guided radiotherapy

et al. 2020

View full text Add to dashboard Cite

show abstract

“…There are however, many advances in our understanding of the role of mpMRI in diagnosis, treatment planning, and post-treatment surveillance that offer increased confidence in introducing focal brachytherapy into the clinic. In particular, we suggest that advances in quantitative imaging (radiomics) provides many opportunities to not only better identify and target high-risk volumes, but also determine a better understanding of the biology and heterogeneity of the tumor(s), providing an opportunity to customize dose prescriptions to the individual patient [ 50 , 68 , 77 ]. For example, identifying regions of hypoxia provides an opportunity to dose escalate to overcome radioresistance in these areas [ 78 , 79 ].…”

Section: Discussion and Future Workmentioning

confidence: 99%

Focal therapy for prostate cancer: the technical challenges

Haworth¹,

Williams²

2017

jcb

View full text Add to dashboard Cite

Focal therapy for prostate cancer has been proposed as an alternative treatment to whole gland therapy, offering the opportunity for tumor dose escalation and/or reduced toxicity. Brachytherapy, either low-dose-rate or high-doserate, provides an ideal approach, offering both precision in dose delivery and opportunity for a highly conformal, non-uniform dose distribution. Whilst multiple consensus documents have published clinical guidelines for patient selection, there are insufficient data to provide clear guidelines on target volume delineation, treatment planning margins, treatment planning approaches, and many other technical issues that should be considered before implementing a focal brachytherapy program. Without consensus guidelines, there is the potential for a diversity of practices to develop, leading to challenges in interpreting outcome data from multiple centers. This article provides an overview of the technical considerations for the implementation of a clinical service, and discusses related topics that should be considered in the design of clinical trials to ensure precise and accurate methods are applied for focal brachytherapy treatments.

show abstract

“…A panel of RT experts proposed in a recent visionary paper that the role of MRI in RT should transit from visual inspection of anatomical changes, which is typically qualitative and subjective in nature, to quantitative measures of functional changes in tumors and critical organs in support of early detection and better assessment of treatment response through advanced quantitative analysis frameworks, such as radiomics and machine‐learning . Quantitative MRI, by its definition, should have three fundamental characteristics: (a) the intensity of MRI should accurately quantify intrinsic tissue properties in vivo , (b) measurements for these MRI measures should have high repeatability, and (c) measurements should have high reproducibility. These three properties enable quantitative MRI metrics as robust indicators of both normal biological and radiation‐induced pathological processes through rigorous statistical analyses with improved sensitivity and specificity.…”

Section: Introductionmentioning

confidence: 99%

Initial assessment of 3D magnetic resonance fingerprinting (MRF) towards quantitative brain imaging for radiation therapy

Chen

Shen

et al. 2019

Medical Physics

View full text Add to dashboard Cite

Purpose Magnetic resonance fingerprinting (MRF) provides quantitative T1/T2 maps, enabling applications in clinical radiotherapy such as large‐scale, multi‐center clinical trials for longitudinal assessment of therapy response. We evaluated the feasibility of a quantitative three‐dimensional‐MRF (3D‐MRF) towards its radiotherapy applications of primary brain tumors. Methods A fast whole‐brain 3D‐MRF sequence initially developed for diagnostic radiology was optimized using flexible body coils, which is the typical MR imaging setup for radiotherapy treatment planning and for MR imaging (MRI)‐guided treatment delivery. Optimization criteria included the accuracy and the precision of T1/T2 quantifications of polyvinylpyrrolidone (PVP) solutions, compared to those from the 3D‐MRF using a 32‐channel head coil. The accuracy of T1/T2 quantifications from the optimized MRF was first examined in healthy volunteers with two different coil setups. The intra‐ and inter‐scanner variations of image intensity from the optimized sequence were quantified by longitudinal scans of the PVP solutions on two 3T scanners. Using a 3D‐printed MRI geometry phantom, susceptibility‐induced distortion with the optimized 3D‐MRF was quantified as the Dice coefficient of phantom contours, compared to those from CT images. By introducing intentional head motion during 10% of the scan, the robustness of the optimized 3D‐MRF towards motion was evaluated through visual inspection of motion artifacts and through quantitative analysis of image sharpness in brain MRF maps. Results The optimized sequence acquired whole‐brain T1, T2 and proton density maps and with a resolution of 1.2 × 1.2 × 3 mm3 in 10 min, similar to the total acquisition time of 3D T1‐ and T2‐weighted images of the same resolution. In vivo T1 and T2 values of the white and gray matter were consistent with literature. The intra‐ and inter‐scanner variability of the intensity‐normalized MRF T1 was 1.0% ± 0.7% and 2.3% ± 1.0% respectively, in contrast to 5.3% ± 3.8% and 3.2% ± 1.6% from the normalized T1‐weighted MRI. Repeatability and reproducibility of MRF T1 were independent of intensity normalization. Both phantom and human data demonstrated that the optimized 3D‐MRF is more robust to subject motion and artifacts from subject‐specific susceptibility difference. Compared to CT contours, the Dice coefficient of phantom contours from 3D‐MRF was 0.93, improved from 0.87 from the T1‐weighted MRI. Conclusion Compared to conventional MRI, the optimized 3D‐MRF demonstrated improved repeatability across time points and reproducibility across scanners for better tissue quantification, as well as improved robustness to subject‐specific susceptibility and motion artifacts under a typical MR imaging setup for radiotherapy. More importantly, quantitative MRF T1/T2 measurements lead to promising potentials towards longitudinal quantitative assessment of treatment response for better adaptive therapy and for large‐scale, multi‐center clinical trials.

show abstract

Quantitative Imaging in Radiation Oncology: An Emerging Science and Clinical Service

Cited by 17 publications

References 108 publications

Medical physics challenges in clinical MR-guided radiotherapy

Medical physics challenges in clinical MR-guided radiotherapy

Focal therapy for prostate cancer: the technical challenges

Initial assessment of 3D magnetic resonance fingerprinting (MRF) towards quantitative brain imaging for radiation therapy

Contact Info

Product

Resources

About