[{sup 18}FDG] PET-CT-Based Intensity-Modulated Radiotherapy Treatment Planning of Head and Neck Cancer

Journal Article · Sat Sep 01 04:00:00 EDT 2007 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2007.04.053· OSTI ID:21036226

El-Bassiouni, Mazen ^[1]; Davis, J Bernard ^[1]; El-Attar, Inas ^[2]; Reiner, Beatrice ^[1]; Burger, Cyrill; Goerres, Gerhard W ^[3]; Studer, Gabriela M ^[1]

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1. Department of Radiation Oncology, Zurich University Hospital, University of Zurich, Zurich (Switzerland)
2. Department of Epidemiology and Statistics, National Cancer Institute, Cairo University, Cairo (Egypt)
3. Department of Nuclear Medicine, Zurich University Hospital, University of Zurich, Zurich (Switzerland)

Purpose: To define the best threshold for tumor volume delineation of the (18) fluoro-2-deoxy-glucose positron emission tomography ({sup 18}FDG-PET) signal for radiotherapy treatment planning of intensity-modulated radiotherapy (IMRT) in head and neck cancer. Methods and Materials: In 25 patients with head-and-neck cancer, CT-based gross tumor volume (GTV{sub CT}) was delineated. After PET-CT image fusion, window level (L) was adapted to best fit the GTV{sub CT}, and GTV{sub PET} was delineated. Tumor maximum (S) and background uptake (B) were measured, and the threshold of the background-subtracted tumor maximum uptake (THR) was used for PET signal segmentation. Gross tumor volumes were expanded to planning target volumes (PTVs) and analyzed. Results: The mean value of S was 40 kBq/mL, S/B ratio was 16, and THR was 26%. The THR correlated with S (r = -0.752), but no correlation between THR and the S/B ratio was seen (r = -0.382). In 77% of cases, S was >30 kBq/mL, and in 23% it was {<=}30 kBq/mL, with a mean THR of 21.4% and 41.6%, respectively (p < 0.001). Using PTV{sub PET} in radiotherapy treatment planning resulted in a reduced PTV in 72% of cases, while covering 88.2% of GTV{sub CT}, comparable to the percentage of GTV{sub PET} covered by PTV{sub CT} (p = 0.15). Conclusions: A case-specific PET signal threshold is optimal in PET-based radiotherapy treatment planning. Signal gating using a THR of 20% in tumors with S >30% {+-} 1.6% kBq/mL and 40% in tumors with S {<=}30% {+-} 1.6% kBq/mL is suitable.

• OSTI ID: 21036226
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 1 Vol. 69; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CARCINOMAS
COMPUTERIZED TOMOGRAPHY
GLUCOSE
HEAD
MODULATION
NECK
PLANNING
POSITRON COMPUTED TOMOGRAPHY
RADIOTHERAPY
UPTAKE