PUB037 Computed Tomography Number Changes of Gross Tumor Volume with MVCT Scans in Tomotherapy May Early Detect the Radiosensitivity of NSCLC Patients

Objective: The correlation between 18F-fluorodexyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) and four-dimensional computed tomography (4DCT) based-tumor volumes is unclear. This prospective study was conducted to determine the optimal threshold of PET/CT for gross tumor volume (GTV) delineation using 4DCT as the standard reference for locally advanced lung cancer patients.Material and Methods: Ten patients with histologically proven primary lung cancer who underwent radiotherapy fromJune 2017 to March 2018 in Ramathibodi Hospital were enrolled in the study. The 4DCT simulation and 18F-FDG PET/CT simulation were performed on the same position and same date. Eight standard uptake value (SUV) thresholds of SUV 1.5.0-2.0 and 15.0-35.0% of maximum SUV were selected for contouring in order to be compared with 4DCT based tumor volumes. The comparison methods used were the mean percentage volume change, dice similarity coefficient (DSC), and 3D-centroid shift of the targets between 18F-FDG PET/CT-based gross tumor volume (GTVPET) and internal gross tumor volume (IGTV) from 4DCT.Results: The largest and smallest volume of primary tumors were 422.6 cm3 and 5.9 cm3. GTVPET contoured using SUV 1.5 (GTVPET1.5) approximated closely to IGTV in all the parameters, including volume change, DSC, and 3D-centroid shift. The best median percentage volume change, median DSC, and median centroid shift between IGTV and GTVPET1.5 were 5.55, 0.745 and 0.37, respectively.Conclusion: GTVPET contoured by 18F-FDG PET at SUV1.5 corresponded most closely to the IGTV in all parameters. Further study with a larger sample size and clinical outcome analysis is needed.

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Optimal standardized uptake value threshold for auto contouring of gross tumor volume using positron emission tomography/computed tomography in patients with operable nonsmall-cell lung cancer: Comparison with pathological tumor size

Indian Journal of Nuclear Medicine ◽

10.4103/ijnm.ijnm_134_20 ◽

2021 ◽

Vol 36 (1) ◽

pp. 7

Author(s):

Jaiprakash Agarwal ◽

Anil Tibdewal ◽

Mangesh Patil ◽

Shagun Misra ◽

Nilendu Purandare ◽

...

Keyword(s):

Computed Tomography ◽

Lung Cancer ◽

Positron Emission Tomography ◽

Tumor Size ◽

Gross Tumor Volume ◽

Tumor Volume ◽

Standardized Uptake Value ◽

Nonsmall Cell Lung Cancer ◽

Emission Tomography ◽

Positron Emission

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MRI to delineate the gross tumor volume of nasopharyngeal cancers: which sequences and planes should be used?

Radiology and Oncology ◽

10.2478/raon-2014-0013 ◽

2014 ◽

Vol 48 (3) ◽

pp. 323-330 ◽

Cited By ~ 4

Author(s):

Aron Popovtzer ◽

Mohannad Ibrahim ◽

Daniel Tatro ◽

Felix Y. Feng ◽

Randall K. Ten Haken ◽

...

Keyword(s):

Computed Tomography ◽

Gross Tumor Volume ◽

Tumor Volume ◽

Nasopharyngeal Cancer ◽

Target Delineation ◽

Weighted Image ◽

Computed Tomography Scans ◽

Target Volumes ◽

Mri Sequences ◽

Uniform Expansions

Abstract Background. Magnetic resonance imaging (MRI) has been found to be better than computed tomography for defining the extent of primary gross tumor volume (GTV) in advanced nasopharyngeal cancer. It is routinely applied for target delineation in planning radiotherapy. However, the specific MRI sequences/planes that should be used are unknown. Methods. Twelve patients with nasopharyngeal cancer underwent primary GTV evaluation with gadolinium-enhanced axial T1 weighted image (T1) and T2 weighted image (T2), coronal T1, and sagittal T1 sequences. Each sequence was registered with the planning computed tomography scans. Planning target volumes (PTVs) were derived by uniform expansions of the GTVs. The volumes encompassed by the various sequences/planes, and the volumes common to all sequences/planes, were compared quantitatively and anatomically to the volume delineated by the commonly used axial T1-based dataset. Results. Addition of the axial T2 sequence increased the axial T1-based GTV by 12% on average (p = 0.004), and composite evaluations that included the coronal T1 and sagittal T1 planes increased the axial T1-based GTVs by 30% on average (p = 0.003). The axial T1-based PTVs were increased by 20% by the additional sequences (p = 0.04). Each sequence/plane added unique volume extensions. The GTVs common to all the T1 planes accounted for 38% of the total volumes of all the T1 planes. Anatomically, addition of the coronal and sagittal-based GTVs extended the axial T1-based GTV caudally and cranially, notably to the base of the skull. Conclusions. Adding MRI planes and sequences to the traditional axial T1 sequence yields significant quantitative and anatomically important extensions of the GTVs and PTVs. For accurate target delineation in nasopharyngeal cancer, we recommend that GTVs be outlined in all MRI sequences/planes and registered with the planning computed tomography scans.

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