The impact of positron emission tomography/computed tomography addition to contrast-enhanced computed tomography findings during radiation treatment planning of locally advanced carcinoma esophagus

Abstract

Introduction: Does metabolic imaging help in better definition of target during radiation treatment planning by bringing about changes in dimensions of the primary tumor in terms of diameter, length, and picking up new skip lesions or nodal stations which in turn prevents geographic misses by including more 18F-fluorodeoxyglucose avid regions not visible on conventional imaging? Materials and Methods: We compared the length and radial dimensions of the primary tumor as well as changes brought about due to addition of new nodal stations, involved structures, and skip lesions in 50 patients of carcinoma esophagus treated between 2011 and 2013, as seen on contrast-enhanced computed tomography (CT) thorax and positron emission tomography (PET)/CT and drew conclusions regarding the technical changes brought about in treatment planning by the additional input of PET/CT. Results and Conclusions: PET-CT tremendously changes treatment plans by expanding the gross tumor volume and including regions which might otherwise have been missed on purely CT-based plans. Of the 50 patients, it changed the contouring and treatment planning of 35 patients and did not impact the remaining 15. Whether this translates into better long-term controls requires further validation by randomized controlled trials, which was not our present objective.

Keywords

• 18f-fluorodeoxyglucose positron emission tomography-computed tomography
• carcinoma esophagus
• contrast-enhanced computed tomography thorax
• radiation planning and contouring guidelines
• target volume delineation