MEDRADSC 2AA3 - Lecture 7.2 - CT in Radiation Therapy

what imaging modality is the current standard for IGRT?

computed tomography (CT)

CT is ______ within the linear accelerator system.

integrated

how does IGRT benefit RT overall?

- improves setup accuracy

- reduces treatment margins

- allows for higher precision in dose administration

- increased individualization of treatment

cone beam CT (CBCT)

a cone-shaped beam is used to capture CT images, where a whole volume of data is acquired, data is acquired in one single rotation and the table does not have to move

how can CBCT be adjusted

collimation in the axial plane, offset of kV detector for larger FOV

limitations of CBCT

cone shape leads to increase in scatter on image, slow gantry rotation causes blurry images with internal motion, limited soft tissue contrast and increased radiation dose to pt

what other imaging modalities can be used in IGRT?

2D x-rays, US and MRI