The Dilemma of Target Delineation with PET/CT in Radiotherapy Planning for Malignant Tumors

• Published in: Cancer biology & medicine Vol. 4; no. 4; p. 428
• Main Authors: ZHU, Suyu, HU, Bingqiang
• Format: Journal Article
• Language: English
• Published: Tianjin Chinese Anti-Cancer Association (CACA), Cancer Biology & Medicine 01.08.2007
• Edition: English ed.
• Subjects: Lymph nodes; Nuclear medicine; Radiation therapy; Tumors
• ISSN: 2095-3941

Currently there are many unanswered questions concern-ing contouring a target with PET/CT in radiotherapy planning. Who should contour the PET volume-the radiation oncologist or the nuclear medicine physician? Which factors will contribute to the dual-observer variability between them? What should be taken as the optimal SUV threshold to demarcate a malignant tumor from the normal tissue? When the PET volume does not coincide with the local area CT findings, which portion should be contoured as the target? If a reginal lymph node draining area or a remote region is shown to be PET positive but CT negative, or PET negative but CT positive, how is the target identified and selected?Further studies concerning the relationship between PET/CT and the cancerous tissue are needed. The long-term clinical results showing an increased therapeutic ratio will finally verify the applicability of guidelines to contour the target with PET/CT in radiotherapy planning.