ABSTRACT
PURPOSE: To study anatomic biologic contouring (ABC), using a previously described distinct halo, to unify volume contouring methods in treatment planning for head and neck cancers. METHODS AND MATERIALS: Twenty-five patients with head and neck cancer at various sites were planned for radiation therapy using positron emission tomography/computed tomography (PET/CT). The ABC halo was used in all PET/CT scans to contour the gross tumor volume (GTV) edge. The CT-based GTV (GTV-CT) and PET/CT-based GTV (GTV-ABC) were contoured by two independent radiation oncologists. RESULTS: The ABC halo was observed in all patients studied. The halo had a standard unit value of 2.19 +/- 0.28. The mean halo thickness was 2.02 +/- 0.21 mm. Significant volume modification (>or=25%) was seen in 17 of 25 patients (68%) after implementation of GTV-ABC. Concordance among observers was increased with the use of the halo as a guide for GTV determination: 6 patients (24%) had a Subject(s)
Head and Neck Neoplasms/diagnostic imaging
, Positron-Emission Tomography/methods
, Tomography, X-Ray Computed/methods
, Aged
, Aged, 80 and over
, Female
, Fluorodeoxyglucose F18
, Humans
, Male
, Middle Aged
, Observer Variation
, Prospective Studies
, Radiopharmaceuticals
