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Radiation Oncology
Published in: Radiation Oncology 1/2017

Open Access 01-12-2017 | Research

The impact of dual energy CT imaging on dose calculations for pre-clinical studies

Authors: Ana Vaniqui, Lotte E. J. R. Schyns, Isabel P. Almeida, Brent van der Heyden, Stefan J. van Hoof, Frank Verhaegen

Published in: Radiation Oncology | Issue 1/2017

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Abstract

Background

To investigate the feasibility of using dual-energy CT (DECT) for tissue segmentation and kilovolt (kV) dose calculations in pre-clinical studies and assess potential dose calculation accuracy gain.

Methods

Two phantoms and an ex-vivo mouse were scanned in a small animal irradiator with two distinct energies. Tissue segmentation was performed with the single-energy CT (SECT) and DECT methods. A number of different material maps was used. Dose calculations were performed to verify the impact of segmentations on the dose accuracy.

Results

DECT showed better overall results in comparison to SECT. Higher number of DECT segmentation media resulted in smaller dose differences in comparison to the reference. Increasing the number of materials in the SECT method yielded more instability. Both modalities showed a limit to which adding more materials with similar characteristics ceased providing better segmentation results, and resulted in more noise in the material maps and the dose distributions. The effect was aggravated with a decrease in beam energy. For the ex-vivo specimen, the choice of only one high dense bone for the SECT method resulted in large volumes of tissue receiving high doses. For the DECT method, the choice of more than one kind of bone resulted in lower dose values for the different tissues occupying the same volume. For the organs at risk surrounded by bone, the doses were lower when using the SECT method in comparison to DECT, due to the high absorption of the bone. SECT material segmentation may lead to an underestimation of the dose to OAR in the proximity of bone.

Conclusions

The DECT method enabled the selection of a higher number of materials thereby increasing the accuracy in dose calculations. In phantom studies, SECT performed best with three materials and DECT with seven for the phantom case. For irradiations in preclinical studies with kV photon energies, the use of DECT segmentation combined with the choice of a low-density bone is recommended.
Footnotes
1
ρ e  = (N A ρZ/A)/(N A ρ w Z w /A w ), where N A is the Avogadro’s number, ρ, Z and A are the mass density, atomic number, and atomic mass of a material, while the subscript w indicates water
 
2
\( {Z}_{eff}={\left({\Sigma}_i{w}_i{Z}_i^{\beta}\right)}^{1/\beta } \), where w i is the weight fraction of element i with atomic number Z i and β = 3.31 [6]
 
Literature
1.
Koontz BF, Verhaegen F, De Ruysscher D. Tumour and normal tissue radiobiology in mouse models: how close are mice to mini-humans? Br J Radiol. 2016;90(1069):20160441.CrossRefPubMed
2.
Grau C, Defourny N, Malicki J, Dunscombe P, Borras JM, Coffey M, et al. Radiotherapy equipment and Departments in the European countries: final results from the ESTRO-HERO survey. Radiother Oncol. 2014;112:155–64.CrossRefPubMed
3.
Verhaegen F, van Hoof S, Granton PV, Trani D. A review of treatment planning for precision image-guided photon beam preclinical animal radiation studies. Z Med Phys. 2014;24:323–34.
4.
Verhaegen F, Granton P, Tryggestad E. Small animal radiotherapy research platforms. Phys Med Biol. 2011;56:R55–83.CrossRefPubMed
5.
Bazalova M, Carrier J-F, Beaulieu L, Verhaegen F. Dual-energy CT-based material extraction for tissue segmentation in Monte Carlo dose calculations. Phys Med Biol. 2008;53:2439–56.CrossRefPubMed
6.
Landry G, Granton PV, Reniers B, Ollers MC, Beaulieu L, Wildberger JE, et al. Simulation study on potential accuracy gains from dual energy CT tissue segmentation for low-energy brachytherapy Monte Carlo dose calculations. Phys Med Biol. 2011;56:6257–78.CrossRefPubMed
7.
Clarkson R, Lindsay PE, Ansell S, Wilson G, Jelveh S, Hill RP, et al. Characterization of image quality and image-guidance performance of a preclinical microirradiator. Med Phys. 2011;38:845–56.CrossRefPubMedPubMedCentral
8.
Granton PV, Verhaegen F. On the use of an analytic source model for dose calculations in precision image-guided small animal radiotherapy. Phys Med Biol. 2013;58:3377–95.CrossRefPubMed
9.
Ma CM, Coffey CW, Dewerd LA, Liu C, Nath R, Seltzer SM, et al. AAPM protocol for 40–300 kV x-ray beam dosimetry in radiotherapy and radiobiology. Med Phys. 2001;28:868–93.CrossRefPubMed
10.
Feldkamp LA, Davis LC, Kress JW. Practical cone-beam algorithm. J Opt Soc Am A. 1984;1:612.CrossRef
11.
Schyns LEJR, Almeida IP, van Hoof SJ, Descamps B, Vanhove C, Landry G, et al. Optimizing dual energy cone beam CT protocols for preclinical imaging and radiation research. Br J Radiol. 2016:1–10.
12.
Saito M. Potential of dual-energy subtraction for converting CT numbers to electron density based on a single linear relationship. Med Phys. 2012;39:2021–30.CrossRefPubMed
13.
Landry G, Seco J, Gaudreault M, Verhaegen F. Deriving effective atomic numbers from DECT based on a parameterization of the ratio of high and low linear attenuation coefficients. Phys Med Biol. 2013;58:6851–66.CrossRefPubMed
14.
ICRU. Tissue Substitutes in Radiation Dosimetry and Measurement, ICRU Report 44. Bethesda: International Commission on Radiation Units and Measurements. 1989. p. 1–189.
15.
van Hoof SJ, Granton PV, Verhaegen F. Development and validation of a treatment planning system for small animal radiotherapy: SmART-plan. Radiother. Oncol. 2013;109:361–6.
16.
Walters BRB, Kawrakow I, Rogers DWO. DOSXYZnrc Users Manual, NRC Report PIRS-0794 (rev B). 2005;1–125.
17.
Kawrakow I, Rogers DWO. The EGSnrc code system: Monte Carlo simulation of electron and photon transport. Technical Report PIRS-701 (4th printing). Ottawa: National Research Council of Canada; 2001.
18.
Poludniowski G, Evans PM. Calculation of x-ray spectra emerging from an x-ray tube. Part I: electron penetration characteristics in x-ray targets. Med Phys. 2007;34:2175–86.
19.
Poludniowski G, Landry G, DeBlois F, Evans PM, Verhaegen F. SpekCalc: a program to calculate photon spectra from tungsten anode x-ray tubes. Phys Med Biol. 2009;54:N433–8.CrossRefPubMed
20.
Chow JCL, Leung MKK, Lindsay PE, Jaffray DA. Dosimetric variation due to the photon beam energy in the small-animal irradiation: a Monte Carlo study. Med. Phys. 2010;37:5322–9.
21.
22.
Granton PV, Dubois L, van Elmpt W, van Hoof SJ, Lieuwes NG, De Ruysscher D, et al. A longitudinal evaluation of partial lung irradiation in mice by using a dedicated image-guided small animal irradiator. Int J Radiat Oncol Biol Phys Elsevier Inc. 2014;90:696–704.CrossRef
23.
Balvert M, van Hoof SJ, Granton PV, Trani D, den Hertog D, Hoffmann AL, et al. A framework for inverse planning of beam-on times for 3D small animal radiotherapy using interactive multi-objective optimisation. Phys Med Biol Inst Physics Publishing. 2015;60:5681–98.CrossRef
24.
Chow JCL. Depth dose dependence of the mouse bone using kilovoltage photon beams: a Monte Carlo study for small-animal irradiation. Radiat Phys Chem Elsevier. 2010;79:567–74.CrossRef
25.
Landry G, Gaudreault M, van Elmpt W, Wildberger JE, Verhaegen F. Improved dose calculation accuracy for low energy brachytherapy by optimizing dual energy CT imaging protocols for noise reduction using sinogram affirmed iterative reconstruction. Z. Med. Phys. Elsevier GmbH. 2016;26:75–87.
Metadata
Title
The impact of dual energy CT imaging on dose calculations for pre-clinical studies
Authors
Ana Vaniqui
Lotte E. J. R. Schyns
Isabel P. Almeida
Brent van der Heyden
Stefan J. van Hoof
Frank Verhaegen
Publication date
01-12-2017
Publisher
BioMed Central
Published in
Radiation Oncology / Issue 1/2017
Electronic ISSN: 1748-717X
DOI
https://doi.org/10.1186/s13014-017-0922-9

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