SU-E-T-192: Computer Vision for Final Online Treatment Parameter Verification.

Purpose: In a typical model of Radiation Oncology data flow, treatment plan is designed on treatment planning station (TPS) under the supervision of physician and physicist, and machine specific parameters are pushed to Record and Verify system (RV) for treatment data storage, where it stays available for daily uploads to treatment station. While various QA programs could be established to verify uncorrupted planning data storage and transfer, the ultimate goal is a daily confirmation of patient treatment parameters versus original treatment plan.

Methods: A new computer vision approach, RTcheck, is used to digitize loaded machine parameters directly from the screen of Varian Clinical Console every time before the beam is turned on by a therapist.

SU-E-T-187: Clinical Use of the Software for the Automation of Treatment Field Parameters Verification Prior to Radiation Delivery.

Purpose: Verification of treatment field parameters by therapists take place prior to every or first fraction. Such verification or field timeout should be completely independent from record-and-verify system. It is performed manually via reading treatment parameters from linac screen and comparing them to treatment plan.

Correction of image artifacts from treatment couch in cone-beam CT from kV on-board imaging.

Purpose: To investigate image artifacts caused by a standard treatment couch on cone-beam CT (CBCT) images from a kV on-board imager and to develop an algorithm based on spatial domain filtering to remove image artifacts in CBCT induced by the treatment couch.

Methods: Image artifacts in CBCT induced by the treatment couch were quantified by scanning a phantom used to quantify CT image performance. This was performed by scanning the phantom setup on a regular treatment couch and in air with the kV on-board imager.

Accurate positioning for head and neck cancer patients using 2D and 3D image guidance.

Our goal is to determine an optimized image-guided setup by comparing setup errors determined by two-dimensional (2D) and three-dimensional (3D) image guidance for head and neck cancer (HNC) patients immobilized by customized thermoplastic masks. Nine patients received weekly imaging sessions, for a total of 54, throughout treatment. Patients were first set up by matching lasers to surface marks (initial) and then translationally corrected using manual registration of orthogonal kilovoltage (kV) radiographs with DRRs (2D-2D) on bony anatomy.

Evaluation of respiration-correlated digital tomosynthesis in lung.

Digital tomosynthesis (DTS) with a linear accelerator-mounted imaging system provides a means of reconstructing tomographic images from radiographic projections over a limited gantry arc, thus requiring only a few seconds to acquire. Its application in the thorax, however, often results in blurred images from respiration-induced motion. This work evaluates the feasibility of respiration-correlated (RC) DTS for soft-tissue visualization and patient positioning.