This is a single-center, prospective pilot study evaluating the utility of HyperSight CBCT imaging and Ethos adaptive radiation planning in pediatric patients receiving radiation therapy for non-cranial tumors. Twenty patients aged 18 or under will be enrolled. Participants will receive standard-of-care radiation therapy, with the addition of twice-weekly HyperSight CBCT scans. These scans will be used to assess anatomical changes and generate adapted radiation plans using the Ethos platform. Radiation oncologists and radiation therapists will independently evaluate the need for adaptation, and adapted vs. scheduled plans will be compared using dosimetric and anatomical similarity metrics. An optional sub-study will allow anonymized imaging and planning data to be shared with Varian Medical Systems. The study duration will match the patient's treatment course, typically 1-6 weeks, with no additional follow-up beyond standard care.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
20
During the standard of care pediatric radiation treatment, a Cone Beam Computed Tomography (CBCT) image is taken after the patient is positioned on the radiation treatment table. This image, captured using equipment built into the treatment machine, helps ensure accurate alignment and allows assessment of tumor or tissue changes.
Princess Margaret Cancer Centre
Toronto, Ontario, Canada
RECRUITINGDice Similarity Coefficient
Change in Tumor and OAR Anatomy During Pediatric Radiation Therapy Using HyperSight CBCT and Ethos Adaptive Replanning. This outcome measures how tumor and organ-at-risk (OAR) anatomy changes during pediatric radiation therapy using HyperSight CBCT.
Time frame: From baseline (start of radiation treatment) to end of treatment, approximately 6 to 8 weeks.
Hausdorff distance
Change in Tumor and OAR Anatomy During Pediatric Radiation Therapy Using HyperSight CBCT and Ethos Adaptive Replanning. This outcome measures how tumor and organ-at-risk (OAR) anatomy changes during pediatric radiation therapy using HyperSight CBCT. This will be measured in mm.
Time frame: From baseline (start of radiation treatment) to end of treatment, approximately 6 to 8 weeks.
Volume differences
Change in Tumor and OAR Anatomy During Pediatric Radiation Therapy Using HyperSight CBCT and Ethos Adaptive Replanning. This outcome measures how tumor and organ-at-risk (OAR) anatomy changes during pediatric radiation therapy using HyperSight CBCT. This will be measured in cm\^3.
Time frame: Time Frame: From baseline (start of radiation treatment) to end of treatment, approximately 6 to 8 weeks.
Quality of cone beam CT
Using the 5 liker scale
Time frame: From baseline to end of treatment (approximately 6 to 8 weeks)
Organ motion
Does the dose to the organ that day violate the prespecified constraints
Time frame: From baseline to end of treatment (approximately 6 to 8 weeks)
Feasibility of Conformal Planning in Traditionally Field-Based Diseases
All target coverage goals achieved with conformal planning measured in percentage (%).
Time frame: From baseline to end of treatment (approximately 6 to 8 weeks)
Feasibility of Conformal Planning in Traditionally Field-Based Diseases
All target coverage goals achieved with conformal planning measured in volume (mm\^3)
Time frame: From baseline to end of treatment (approximately 6 to 8 weeks)
Feasibility of Conformal Planning in Traditionally Field-Based Diseases
All target coverage goals achieved with conformal planning measured in dose (gy)
Time frame: From baseline to end of treatment (approximately 6 to 8 weeks)
Dosimetric Impact of Adaptive Radiation Therapy
Measures the differences in accumulated radiation dose to the tumor and organs at risk (OARs) between adapted and non-adapted treatment plans using dose-volume metrics.
Time frame: From baseline to end of treatment (approximately 6 to 8 weeks)
Safety of Minimized Target Expansion Volumes
Evaluates whether reducing target margins in adaptive planning maintains safe dose coverage while avoiding increased exposure to surrounding healthy tissue. All target coverage goals achieved with smaller PTV sizes. It's a pre-defined metric that is specific to the tumour type. A common example is the dose to 95% of the PTV should be \>95% of the prescription dose.
Time frame: From baseline to end of treatment (approximately 6 to 8 weeks)
Integration of Radiation Therapy Proficiencies in Adaptive Planning
Image review, contour adjustments, and plan selection during daily treatment sessions. Measured \>=0.70 Dice Similarity Coefficient between radiation oncology and radiation therapy delineations.
Time frame: From baseline to end of treatment (approximately 6 to 8 weeks)
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