Effects of 16-bit CT imaging scanning conditions for metal implants on radiotherapy dose distribution

Gao,Liugang; Sun,Hongfei; Ni,Xinye; Fang,Mingming; Lin,Tao

doi:10.3892/ol.2017.7586

February-2018 Volume 15 Issue 2

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February-2018 Volume 15 Issue 2

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Article Open Access

Effects of 16-bit CT imaging scanning conditions for metal implants on radiotherapy dose distribution

Authors:
- Liugang Gao
- Hongfei Sun
- Xinye Ni
- Mingming Fang
- Tao Lin
View Affiliations / Copyright

Affiliations: Radiotherapy Department, Second People's Hospital of Changzhou, Nanjing Medical University, Changzhou 213003, P.R. China, Radiotherapy Department, Changzhou Cancer Hospital of Soochow University, Changzhou 213001, P.R. China

Copyright: © Gao et al. This is an open access article distributed under the terms of Creative Commons Attribution License.
Pages: 2373-2379
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Published online on: December 11, 2017

https://doi.org/10.3892/ol.2017.7586
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Abstract

Dose distribution was calculated and analyzed on the basis of 16‑bit computed tomography (CT) images in order to investigate the effect of scanning conditions on CT for metal implants. Stainless steel and titanium rods were inserted into a phantom, and CT images were obtained by scanning the phantom under various scanning conditions: i) Fixed tube current of 230 mA and tube voltages of 100, 120, and 140 kV; and ii) fixed tube voltage of 120 kV and tube currents of 180, 230, and 280 mA. The CT value of the metal rod was examined and corrected. In a Varian treatment planning system, a treatment plan was designed on the basis of the CT images obtained under the set scanning conditions. The dose distributions in the phantom were then calculated and compared. The CT value of the metal area slightly changed upon tube current alteration. The dose distribution in the phantom was also similar. The maximum CT values of the stainless steel rod were 14,568, 14,127 and 13,295 HU when the tube voltages were modified to 100, 120, and 140 kV, respectively. The corresponding CT values of the titanium rod were 9,420, 8,140 and 7,310 HU. The dose distribution of the radiotherapy plan changed significantly as the tube voltage varied. Compared with the reference dose, the respective maximum dose differences of the stainless steel and titanium rods in the phantom were 5.70, and 6.62% when the tube voltage varied. The changes in tube currents resulted in a maximum dose error of <1% for stainless steel and titanium. In CT imaging, changes in tube voltages can significantly alter the CT values of metal implants. Thus, this can lead to large errors in radiotherapy dose distributions.

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Journals

International Journal of Molecular Medicine

International Journal of Oncology

Molecular Medicine Reports

Oncology Reports

Experimental and Therapeutic Medicine

Oncology Letters

Biomedical Reports

Molecular and Clinical Oncology

World Academy of Sciences Journal

International Journal of Functional Nutrition

International Journal of Epigenetics

Medicine International

Effects of 16-bit CT imaging scanning conditions for metal implants on radiotherapy dose distribution

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