Pilot study to validate the new design and workflow of Cone-Beam CT imaging for radiation therapy treatment simulation.

This study is a prospective, non-randomized imaging evaluation study. A cohort of subjects undergoing standard of care radiation therapy will be selected based on malignancies from six disease sites. The Halcyon 4.0 images acquired in place of standard evaluation CT scans during the course of treatment will be used for target volume delineation and normal structures segmentation. Treatment plans will be recalculated based on the Halcyon 4.0 images from this system and compared to the original treatment plan. Dose differences will be evaluated. Two-tailed t-test will be used to compare the statistical significance of the dosimetric results as well as the volumetric differences among target volume and the volumes of organs at risk.

Inclusion Criteria:

• Subjects will be treated with external beam radiotherapy at the Perelman Center for Advanced Medicine for any of the following malignancies: head-and-neck, thoracic, breast, gastrointestinal, gynecologic, or genitourinary.
• Age ≥ 18 years
• Ability to understand the requirements of the study and to give written informed consent, as determined by the treating physician
• Availability of a complete set of treatment plans, including CT simulation images, target and normal structure contours, and radiation treatment prescriptions

Exclusion Criteria:

• Subjects who are pregnant or have plans for pregnancy during the period of treatment.
• Any malignancy not stated above.
• Those unable to be treated on any linear accelerator (whether Truebeam™ or Halcyon™) unit either due to subject anatomy or treatment plan.
• Those undergoing proton therapy.