Comparison of patient megavoltage cone beam CT images acquired with an unflattened beam from a carbon target and a flattened treatment beama)

Abstract

The IBL has the advantage of improved image quality at the same dose, or reduced dose for the same image quality, over the TBL.

Prostate Image-Guided Radiotherapy by Megavolt Cone-Beam CT

“…Despite such encouraging results, the main difficulties of using MV-CBCT for soft tissue registration remain the low signal/noise and the low soft-tissue contrast. New approaches to generate soft-tissue improved MV-CBCT using low Z target are currently proposed and will likely reduce the gap with respect to kV-CBCT [7,25]. These approaches have the advantage of improved image quality at the same dose, or reduced the dose for the same image quality.…”

Image quality improvement in megavoltage cone beam CT using an imaging beam line and a sintered pixelated array system

“…As MVCBCT image quality improves, the clinical adoption of MVCBCT-based dose-guided radiation therapy 12,13 becomes increasingly attractive. MVCBCT image quality for the MVision TM system has been improved through the introduction of an unflattened 4.2 MV imaging beam line (IBL) with a low atomic number (Z) target material such as graphite 11,14,15 or diamond, 16 rather than the tungsten electron target used for the TBL. Low-Z MVCBCT imaging has also been implemented on a Varian (Palo Alto, CA) accelerator using aluminum 17,18 and beryllium 18 electron targets and on an Elekta (Stockholm, Sweden) linear accelerator with a carbon electron target.…”

Image quality and dose distributions of three linac-based imaging modalities

“…Several studies have evaluated the image quality and dosimetric properties of the various modalities [5][6][7]13,15,25,29], but to date these techniques have not been compared with respect to imaging dose and dose distribution. We therefore present dose distributions from these techniques both for planar and CBCT imaging, for patients with prostate cancer and head-and-neck cancer.…”