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Clinical Trial
. 2013 May 16;8(5):e64665.
doi: 10.1371/journal.pone.0064665. Print 2013.

Improvement of internal tumor volumes of non-small cell lung cancer patients for radiation treatment planning using interpolated average CT in PET/CT

Yao-Ching Wang  1 , Hsun-Lin Tseng, Yang-Hsien Lin, Chia-Hung Kao, Wei-Chien Huang, Tzung-Chi Huang
Affiliations
Clinical Trial

Improvement of internal tumor volumes of non-small cell lung cancer patients for radiation treatment planning using interpolated average CT in PET/CT

Yao-Ching Wang et al. PLoS One. .

Abstract

Respiratory motion causes uncertainties in tumor edges on either computed tomography (CT) or positron emission tomography (PET) images and causes misalignment when registering PET and CT images. This phenomenon may cause radiation oncologists to delineate tumor volume inaccurately in radiotherapy treatment planning. The purpose of this study was to analyze radiology applications using interpolated average CT (IACT) as attenuation correction (AC) to diminish the occurrence of this scenario. Thirteen non-small cell lung cancer patients were recruited for the present comparison study. Each patient had full-inspiration, full-expiration CT images and free breathing PET images by an integrated PET/CT scan. IACT for AC in PET(IACT) was used to reduce the PET/CT misalignment. The standardized uptake value (SUV) correction with a low radiation dose was applied, and its tumor volume delineation was compared to those from HCT/PET(HCT). The misalignment between the PET(IACT) and IACT was reduced when compared to the difference between PET(HCT) and HCT. The range of tumor motion was from 4 to 17 mm in the patient cohort. For HCT and PET(HCT), correction was from 72% to 91%, while for IACT and PET(IACT), correction was from 73% to 93% (*p<0.0001). The maximum and minimum differences in SUVmax were 0.18% and 27.27% for PET(HCT) and PET(IACT), respectively. The largest percentage differences in the tumor volumes between HCT/PET and IACT/PET were observed in tumors located in the lowest lobe of the lung. Internal tumor volume defined by functional information using IACT/PET(IACT) fusion images for lung cancer would reduce the inaccuracy of tumor delineation in radiation therapy planning.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Illustrates the generation of IACT from full-inspiration and full-expiration images by OFM.
The resulted deformation matrix is then used to interpolate the phases in between with 4 equal spatial steps. The IACT is the average of the two original phases and the interpolated 3 phases (ICTs) for attenuation correction in PET reconstruction.
Figure 2
Figure 2. Represents the PET/CT fusion for tumor contour delineation.
The arrows indicate the mismatch observed in PETHCT/HCT fusion between PETHCT and HCT, showing the (A) transverse (B) coronal and (C) sagittal view. The image fusion with PETIACT and IACT is seen in the (D) transverse (E) coronal and (F) sagittal view.
Figure 3
Figure 3. Shows the percentage difference in the tumor volume and the SUVmax between delineations from HCT/PETHCT and IACT/PETIACT versus the tumor location inside the lung.
See this image and copyright information in PMC

References

    1. Ashamalla H, Rafla S, Parikh K, Mokhtar B, Goswami G, et al. (2005) The contribution of integrated PET/CT to the evolving definition of treatment volumes in radiation treatment planning in lung cancer. Int. J. Radiat. Oncol. Biol. Phys. 63(4): 1016–23. - PubMed
    1. Kao CH, Hsieh TC, Yu CY, Yen KY, Yang SN, et al. (2010) 18F-FDG PET/CT-based gross tumor volume definition for radiotherapy in head and neck cancer: a correlation study between suitable uptake value threshold and tumor parameters. Radiat. Oncol. 5: 76. - PMC - PubMed
    1. Aristophanous M, Berbeco RI, Killoran JH, Yap JT, Sher DJ, et al. (2012) Clinical utility of 4D FDG-PET/CT scans in radiation treatment planning. Int. J. Radiat. Oncol. Biol. Phys. 82(1): 99–105. - PubMed
    1. Steenbakkers RJ, Duppen JC, Fitton I, Deurloo KE, Zijp LJ, et al. (2006) Reduction of observer variation using matched CT-PET for lung cancer delineation: a three dimensional analysis. Int. J. Radiat. Oncol. Biol. Phys. 64: 435–48. - PubMed
    1. van Baardwijk A, Bosmans G, Boersma L, Buijsen J, Wanders S, et al. (2007) PET-CT–based auto-contouring in non–small-cell lung cancer correlates with pathology and reduces interobserver variability in the delineation of the primary tumour and involved nodal volumes. Int. J. Radiat. Oncol. Biol. Phys. 68: 771–8. - PubMed

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