Abstract
Abstract Kilo-voltage cone beam computed tomography (kV-CBCT) integrated with a linac can produce online volumetric and anatomical images for patient set-up and dosimetric analysis in adaptive radiotherapy. However CBCT is prone to motion artifacts. This study investigates the impact of target motion in CBCT imaging. To simulate respiratory movement, a dynamic phantom was moved in three-dimensions with a period of 4 s and two different amplitudes (PA1 and PA2). The targets of well defined geometries were made using wax. A reference image of the static target was achieved with fan beam CT. Using CBCT, the targets in static and dynamic modes were imaged under full-fan beam conditions. The length of average HU spread was reduced in range from 19.35 to 44.44% along the cranio-caudal direction of targets. The percentage volume loss of dynamic targets imaged using CBCT (for Hounsfield Units with window width -500 to 0) ranged from 14.35 to 30.95% for PA1 and 21.29 to 43.80% for PA2 in comparison with static targets imaged with fan beam CT. A significant loss of volumetric information may result for non-gated CBCT imaging of moving targets and may result in a systematic error in re-contouring when CBCT images are used for radiotherapy re-planning.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 59-64 |
| Number of pages | 6 |
| Journal | Australasian Physical and Engineering Sciences in Medicine |
| Volume | 33 |
| Issue number | 1 |
| DOIs | |
| State | Published - Mar 2010 |
| Externally published | Yes |
Keywords
- KV-CBCT
- Re-contouring
- Systematic error
- Target motion
ASJC Scopus subject areas
- Biophysics
- Biomedical Engineering
- Radiology Nuclear Medicine and imaging
- Physics and Astronomy(all)