4D Cone Beam CT Reconstruction for Radiotherapy Via Motion Vector Optimization

The University of Texas System (UT)

Status: Terminated

Conditions: Lung Cancer

Treatments: Radiation: CBCT scan

Study type: Observational

Funder types: Other

Identifiers

NCT03551405

STU 082014-030

Details and patient eligibility

About

To validate a new 4D Cone Beam CT (4DCBCT) reconstruction algorithm that was developed in our research group recently in terms of its geometry and intensity accuracy through real patient studies. Dose calculation found out in this study will not be used on the subject

Full description

Before patient studies, we will have conducted experimental studies on a lung phantom.

The purpose of this step is to comprehensively evaluate the system performance and gain confidence prior to its applications to real patient cases. We will operate the phantom to simulate motion patterns with different motion amplitude/frequency. 4DCBCT images will be reconstructed using our method and the conventional FDK algorithm. The validation will focus on two aspects: HU value accuracy and anatomy location accuracy.

Imaging dose in these scans will be also measured in phantom studies to make sure the radiation dose level is acceptable for patient studies. adiation dose level is acceptable for patient studies.

After testing the reconstruction algorithm on phantoms, we will move on to real patient cases. We will conduct patient studies on lung cancer patients treated under Image Guided Radiation Therapy (IGRT) at Department of Radiation Oncology, UT Southwestern Medical Center. CBCT projection data will be collected (4 gantry rotations, each within 1 minute) in only one treatment fraction. 4DCBCT images will be reconstructed from the current standard FDK algorithm using all the projection data, and from our system using data only in the first gantry rotation. Patient 4DCT image will also be used, which have been acquired during treatment planning stage per standard treatment protocol at UTSW.

The image quality of our 4DCBCT will be assessed in two aspects:

1. geometry accuracy, by comparing selected anatomical landmark locations with those in 4DCBCT reconstructed by the FDK algorithm. 2) HU accuracy, by comparing HU values in selected regions of interest (ROIs) with those in 4DCT.

The 4DCT images will be extracted from radiation therapy information system MOSAIQ.

The CBCT projection data will be exported from a computer that controls the image acquisition system

Enrollment: 18 patients

Sex: All

Ages: 18 to 99 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

1. Patients that have been diagnosed with lung cancer, and are treated at Department of Radiation Oncology, UTSW.
2. Patients are greater than 18 years of age.
3. Patients understand a written informed consent document and are willing to sign the consent form.

Exclusion criteria

1. Women who are pregnant or trying to get pregnant
2. Children (under age of 18)

Trial design

18 participants in 1 patient group

Intensity accuracy

Description:

The difference of the HU values in corresponding ROIs in the two image sets will be compared with zero using one sample t-test. In addition, we will also use these patient cases to test the computational efficiency of our algorithm. Based on our preliminary study, it is expected that the computation time will be 5\~10 sec per phase. The reconstruction time will be recorded in these patient cases and will be assessed.

Treatment:

Radiation: CBCT scan