Journal article
Estimation of organ doses from kilovoltage cone-beam CT imaging used during radiotherapy patient position verification
Medical physics (Lancaster), Vol.37(9), pp.4620-4626
08/10/2010
DOI: 10.1118/1.3476459
PMID: 20964180
Abstract
Purpose:
The purpose of this study was to develop a practical method for estimating organ doses from kilovoltage cone-beam CT (CBCT) that can be performed with readily available phantoms and dosimeters. The accuracy of organ dose estimates made using the ImPACT patient dose calculator was also evaluated.
Methods:
A 100 mm pencil chamber and standard CT dose index (CTDI) phantoms were used to measure the cone-beam dose index (CBDI). A weighted CBDI
(
CBDI
w
)
was then calculated from these measurements to represent the average volumetric dose in the CTDI phantom. By comparing
CBDI
w
to the previously published organ doses, organ dose conversion coefficients were developed. The measured CBDI values were also used as inputs for the ImPACT calculator to estimate organ doses. All CBDI dose measurements were performed on both the Elekta XVI and Varian OBI at three clinically relevant locations: Head, chest, and pelvis.
Results:
The head, chest, and pelvis protocols yielded
CBDI
w
values of 0.98, 16.62, and 24.13 mGy for the XVI system and 5.17, 6.14, and 21.57 mGy for the OBI system, respectively. Organ doses estimated with the ImPACT CT dose calculator showed a large range of variation from the previously measured organ doses, demonstrating its limitations for use with CBCT.
Conclusions:
The organ dose conversion coefficients developed in this work relate
CBDI
w
values to organ doses previously measured using the same clinical protocols. Ultimately, these coefficients will allow for the quick estimation of organ doses from routine measurements performed using standard CTDI phantoms and pencil chambers.
Details
- Title: Subtitle
- Estimation of organ doses from kilovoltage cone-beam CT imaging used during radiotherapy patient position verification
- Creators
- Daniel Hyer - Department of Radiation Oncology, University of Iowa Hospitals and Clinics, 200 Hawkins Drive,Iowa City, Iowa 52242David Hintenlang - University of Florida, 202 Nuclear Sciences Center, P.O. Box 118300, Gainesville, Florida 32611
- Resource Type
- Journal article
- Publication Details
- Medical physics (Lancaster), Vol.37(9), pp.4620-4626
- Publisher
- American Association of Physicists in Medicine
- DOI
- 10.1118/1.3476459
- PMID
- 20964180
- ISSN
- 0094-2405
- eISSN
- 2473-4209
- Grant note
- DE-GF07-05ID14700 / DOE TKC 30-07 185-01 / UNSPECIFIED
- Language
- English
- Date published
- 08/10/2010
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiation Oncology
- Record Identifier
- 9984047749002771
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