CT-on-Rails Versus In-Room CBCT for Online Daily Adaptive Proton Therapy of Head-and-Neck Cancers

Nesteruk, Konrad Pawel; Bobić, Mislav; Lalonde, Arthur; Winey, Brian; Lomax, Anthony; Paganetti, Harald

doi:10.3390/cancers13235991

Cited by 21 publications

(27 citation statements)

References 36 publications

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“…The patient cohort and treatment plans used for this study were identical to those used in our previous works [ 8 , 15 , 19 ]. The dataset includes 10 H&N patients with the planning CT image and daily acquired CBCT images.…”

Section: Methodsmentioning

confidence: 99%

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Low-Dose Computed Tomography Scanning Protocols for Online Adaptive Proton Therapy of Head-and-Neck Cancers

Nesteruk

Bobić

Sharp

et al. 2022

Cancers

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Purpose: To evaluate the suitability of low-dose CT protocols for online plan adaptation of head-and-neck patients. Methods: We acquired CT scans of a head phantom with protocols corresponding to CT dose index volume CTDIvol in the range of 4.2–165.9 mGy. The highest value corresponds to the standard protocol used for CT simulations of 10 head-and-neck patients included in the study. The minimum value corresponds to the lowest achievable tube current of the GE Discovery RT scanner used for the study. For each patient and each low-dose protocol, the noise relative to the standard protocol, derived from phantom images, was applied to a virtual CT (vCT). The vCT was obtained from a daily CBCT scan corresponding to the fraction with the largest anatomical changes. We ran an established adaptive workflow twice for each low-dose protocol using a high-quality daily vCT and the corresponding low-dose synthetic vCT. For a relative comparison of the adaptation efficacy, two adapted plans were recalculated in the high-quality vCT and evaluated with the contours obtained through deformable registration of the planning CT. We also evaluated the accuracy of dose calculation in low-dose CT volumes using the standard CT protocol as reference. Results: The maximum differences in D98 between low-dose protocols and the standard protocol for the high-risk and low-risk CTV were found to be 0.6% and 0.3%, respectively. The difference in OAR sparing was up to 3%. The Dice similarity coefficient between propagated contours obtained with low-dose and standard protocols was above 0.982. The mean 2%/2 mm gamma pass rate for the lowest-dose image, using the standard protocol as reference, was found to be 99.99%. Conclusion: The differences between low-dose protocols and the standard scanning protocol were marginal. Thus, low-dose CT protocols are suitable for online adaptive proton therapy of head-and-neck cancers. As such, considering scanning protocols used in our clinic, the imaging dose associated with online adaption of head-and-neck cancers treated with protons can be reduced by a factor of 40.

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Section: Methodsmentioning

confidence: 99%

“…Most adaptive proton workflows published assume the use of CT for daily imaging. The workflow developed at MGH was initially conceived for CBCT, but we also considered its application in centers equipped with CT-on-rails [ 15 ]. One of the most important advantages of using fan-beam CT is the much better image quality.…”

Section: Introductionmentioning

confidence: 99%

Low-Dose Computed Tomography Scanning Protocols for Online Adaptive Proton Therapy of Head-and-Neck Cancers

Nesteruk

Bobić

Sharp

et al. 2022

Cancers

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“…If setup uncertainties between an out-of-room planning vertical CT are deemed too large, or no space for a second upright positioning system with vertical CT is available, in-room x-ray CT not at isocenter may be more practical. In a recent study, Nesteruk et al (59) have found no significant difference between in-isocenter cone-beam CT (CBCT) based treatment planning, and treatment planning based on a CT-on-rails for supine position. The same may be the case for upright, such that an in-room CT instead of one at isonceter may provide sufficient accuracy.…”

Section: Image Guidance For Upright Positionsmentioning

confidence: 99%

Considerations for Upright Particle Therapy Patient Positioning and Associated Image Guidance

et al. 2022

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Particle therapy is a rapidly growing field in cancer therapy. Worldwide, over 100 centers are in operation, and more are currently in construction phase. The interest in particle therapy is founded in the superior target dose conformity and healthy tissue sparing achievable through the particles’ inverse depth dose profile. This physical advantage is, however, opposed by increased complexity and cost of particle therapy facilities. Particle therapy, especially with heavier ions, requires large and costly equipment to accelerate the particles to the desired treatment energy and steer the beam to the patient. A significant portion of the cost for a treatment facility is attributed to the gantry, used to enable different beam angles around the patient for optimal healthy tissue sparing. Instead of a gantry, a rotating chair positioning system paired with a fixed horizontal beam line presents a suitable cost-efficient alternative. Chair systems have been used already at the advent of particle therapy, but were soon dismissed due to increased setup uncertainty associated with the upright position stemming from the lack of dedicated image guidance systems. Recently, treatment chairs gained renewed interest due to the improvement in beam delivery, commercial availability of vertical patient CT imaging and improved image guidance systems to mitigate the problem of anatomical motion in seated treatments. In this review, economical and clinical reasons for an upright patient positioning system are discussed. Existing designs targeted for particle therapy are reviewed, and conclusions are drawn on the design and construction of chair systems and associated image guidance. Finally, the different aspects from literature are channeled into recommendations for potential upright treatment layouts, both for retrofitting and new facilities.

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“…Efforts have been made to enable CBCT for online adaptive planning for proton therapy (53)(54)(55)(56), but it suffers from reduced image quality in comparison to CT due to restricted field of view, lower soft-tissue contrast, and inequivalent relation between CBCT voxel values and Hounsfield units. CT-on-Rails has also been investigated as an alternative to daily CBCT imaging for daily adaptive radiotherapy due to its ability to provide higher quality images at "near-treatmentposition", though widespread adaption of CT-on-Rails is limited due to increased cost and larger footprint (57). Interested readers can find an in-depth discussion on radiological image guidance in particle therapy in the recent review by Landry and Hua (58).…”

Section: Imaging At Simulation and Deliverymentioning

confidence: 99%

Management of Motion and Anatomical Variations in Charged Particle Therapy: Past, Present, and Into the Future

et al. 2022

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The major aim of radiation therapy is to provide curative or palliative treatment to cancerous malignancies while minimizing damage to healthy tissues. Charged particle radiotherapy utilizing carbon ions or protons is uniquely suited for this task due to its ability to achieve highly conformal dose distributions around the tumor volume. For these treatment modalities, uncertainties in the localization of patient anatomy due to inter- and intra-fractional motion present a heightened risk of undesired dose delivery. A diverse range of mitigation strategies have been developed and clinically implemented in various disease sites to monitor and correct for patient motion, but much work remains. This review provides an overview of current clinical practices for inter and intra-fractional motion management in charged particle therapy, including motion control, current imaging and motion tracking modalities, as well as treatment planning and delivery techniques. We also cover progress to date on emerging technologies including particle-based radiography imaging, novel treatment delivery methods such as tumor tracking and FLASH, and artificial intelligence and discuss their potential impact towards improving or increasing the challenge of motion mitigation in charged particle therapy.

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CT-on-Rails Versus In-Room CBCT for Online Daily Adaptive Proton Therapy of Head-and-Neck Cancers

Cited by 21 publications

References 36 publications

Low-Dose Computed Tomography Scanning Protocols for Online Adaptive Proton Therapy of Head-and-Neck Cancers

Low-Dose Computed Tomography Scanning Protocols for Online Adaptive Proton Therapy of Head-and-Neck Cancers

Considerations for Upright Particle Therapy Patient Positioning and Associated Image Guidance

Management of Motion and Anatomical Variations in Charged Particle Therapy: Past, Present, and Into the Future

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