FDG‑PET/CT for Global Assessment of the Maxillary Sinus in Head and Neck Cancer Patients Undergoing Photon/Proton Radiotherapy

Asad A. Siddiqi

Min-Young Kim

Siddiqi, Asad A.1, Kim, Min-Young1, Mouminah, Alaa1, Raynor, William Y2, Werner, Thomas J3, Alavi, Abass3
Faculty / Advisor: Chang, Yu Cheng
1University of Pennsylvania School of Dental Medicine, Department of Periodontics
2Drexel University College of Medicine, Radiology
3Hospital of the University of Pennsylvania, Radiology


As radiation therapy continues to develop,advances in molecular imaging have enabled clinicians to gain insight into post-treatment changes in metabolic activity of tumors and surrounding tissue. For this study we used 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) to detect radiotherapy-induced changes of the maxillary sinuses. Our aim was to assess the feasibility of using FDG-PET/CT to assess the effectiveness of irradiation of the tumor tissue and to determine the presence of damage to the surrounding structures, soft tissue and bone


Sixty-four head and neck cancer patients were treated with three methods of radiation in this retrospective study: 1) photon radiotherapy 2) proton radiotherapy 3) combined photon/proton radiotherapy. The primary sites that received treatment were the tongue, larynx, oropharynx, nasopharynx and hypopharynx. Two FDG-PET/CT scans were obtained for each patient - one at baseline, and one at 3 months follow up; this resulted in 128 total scans. Osirix MD software was used to manually delineate the regions of interest (ROIs) containing the entire left and right maxillary sinuses. The global mean standardized uptake value (global SUVmean) was calculated in each subject as the average SUV among all voxels contained within the left and right ROIs. Inter-rater reliability was assessed by Pearson correlation. A two-tailed paired t-test was used to compare the pre- and post-radiotherapy global SUVmean. Statistical significance of this result was confirmed with a Wilcoxon signed rank test.


Ten subjects were excluded due to imaging and quantification issues, leaving 54 patients to be evaluated. Excellent inter-rater reliability was observed(r=0.99).The average global SUVmean of the maxillary sinus changed between pre-treatment with proton radiotherapy and at 3 months followup, from 0.85 ± 0.20 to 0.77 ± 0.09. For photon radiotherapy, global SUVmean changed from 0.88 ± 0.20 to 0.92 ± 0.24. For combined photon/proton radiotherapy, global SUVmean changed from 0.94 ± 0.36 to 0.82 ± 0.29.


A reproducible method with excellent inter-rater reliability of evaluating the maxillary sinuses within head and neck cancer patients was found.Though not statistically significant, FDG uptake was found to increase after photon radiotherapy on average, while other treatment methods showed a decrease in global SUVmean within the maxillary sinus.By determining the collateral effects of radiotherapy on sites distant from the primarily targeted organs, the treatment modality resulting in less global inflammation can be deduced.