Abstract
Purpose: To provide a noninvasive technique to measure the intensity profile of the fan beam in a computed tomography (CT) scanner that is cost effective and easily implemented without the need to access proprietary scanner information or service modes. Methods: The fabrication of an inexpensive aperture is described, which is used to expose radiochromic film in a rotating CT gantry. A series of exposures is made, each of which is digitized on a personal computer document scanner, and the resulting data set is analyzed to produce a self-consistent calibration of relative radiation exposure. The bow tie profiles were analyzed to determine the precision of the process and were compared to two other measurement techniques, direct measurements from CT gantry detectors and a dynamic dosimeter. Results: The radiochromic film method presented here can measure radiation exposures with a precision of ∼6% root-mean-square relative error. The intensity profiles have a maximum 25% root-mean-square relative error compared with existing techniques. Conclusions: The proposed radiochromic film method for measuring bowtie profiles is an inexpensive (∼$100 USD+film costs), noninvasive method to measure the fan beam intensity profile in CT scanners.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2908-2914 |
| Number of pages | 7 |
| Journal | Medical Physics |
| Volume | 42 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 1 2015 |
| Externally published | Yes |
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Keywords
- bow tie filter
- CT
- radiochromic film
ASJC Scopus subject areas
- Biophysics
- Radiology Nuclear Medicine and imaging
Cite this
Technical Note : Measurement of bow tie profiles in CT scanners using radiochromic film. / Whiting, Bruce R.; Dohatcu, Andreea C.; Evans, Joshua D.; Politte, David G.; Williamson, Jeffrey F.
In: Medical Physics, Vol. 42, No. 6, 01.06.2015, p. 2908-2914.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Technical Note
T2 - Measurement of bow tie profiles in CT scanners using radiochromic film
AU - Whiting, Bruce R.
AU - Dohatcu, Andreea C.
AU - Evans, Joshua D.
AU - Politte, David G.
AU - Williamson, Jeffrey F.
PY - 2015/6/1
Y1 - 2015/6/1
N2 - Purpose: To provide a noninvasive technique to measure the intensity profile of the fan beam in a computed tomography (CT) scanner that is cost effective and easily implemented without the need to access proprietary scanner information or service modes. Methods: The fabrication of an inexpensive aperture is described, which is used to expose radiochromic film in a rotating CT gantry. A series of exposures is made, each of which is digitized on a personal computer document scanner, and the resulting data set is analyzed to produce a self-consistent calibration of relative radiation exposure. The bow tie profiles were analyzed to determine the precision of the process and were compared to two other measurement techniques, direct measurements from CT gantry detectors and a dynamic dosimeter. Results: The radiochromic film method presented here can measure radiation exposures with a precision of ∼6% root-mean-square relative error. The intensity profiles have a maximum 25% root-mean-square relative error compared with existing techniques. Conclusions: The proposed radiochromic film method for measuring bowtie profiles is an inexpensive (∼$100 USD+film costs), noninvasive method to measure the fan beam intensity profile in CT scanners.
AB - Purpose: To provide a noninvasive technique to measure the intensity profile of the fan beam in a computed tomography (CT) scanner that is cost effective and easily implemented without the need to access proprietary scanner information or service modes. Methods: The fabrication of an inexpensive aperture is described, which is used to expose radiochromic film in a rotating CT gantry. A series of exposures is made, each of which is digitized on a personal computer document scanner, and the resulting data set is analyzed to produce a self-consistent calibration of relative radiation exposure. The bow tie profiles were analyzed to determine the precision of the process and were compared to two other measurement techniques, direct measurements from CT gantry detectors and a dynamic dosimeter. Results: The radiochromic film method presented here can measure radiation exposures with a precision of ∼6% root-mean-square relative error. The intensity profiles have a maximum 25% root-mean-square relative error compared with existing techniques. Conclusions: The proposed radiochromic film method for measuring bowtie profiles is an inexpensive (∼$100 USD+film costs), noninvasive method to measure the fan beam intensity profile in CT scanners.
KW - bow tie filter
KW - CT
KW - radiochromic film
UR - http://www.scopus.com/inward/record.url?scp=84929615646&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84929615646&partnerID=8YFLogxK
U2 - 10.1118/1.4921120
DO - 10.1118/1.4921120
M3 - Article
C2 - 26127044
AN - SCOPUS:84929615646
VL - 42
SP - 2908
EP - 2914
JO - Medical Physics
JF - Medical Physics
SN - 0094-2405
IS - 6
ER -