2Özel Anadolu Sağlık Merkezi, Nükleer Tıp Bölümü, Kocaeli OBJECTIVES
The aim of study was to evaluate the possible role of fused images, acquired with a combined positron emission tomography/ computed tomography (PET/CT) scanner, in delineating gross tumor volume (GTV) and clinical target volume (CTV).
METHODS
Twenty-five patients with small cell lung (SCL) or non-small
cell lung (NSCL) cancer were studied. CT and PET images
were obtained in treatment position. GTV and CTV were defined
first using the CT alone and then using the registered
CT and PET. For each patient, two 3D-conformal radiotherapy
(CRT) plans were made and they were compared with respect
to the GTV, CTV, mean lung dose (MLD) and Vlung20Gy.
RESULTS
PET changed GTV in 17 patients. PET increased CTV in 7
patients. In 16 patients with atelectasis, decrease in CTV led
to reduced dose to the lung. CTV enlarged and values of MLD
and Vlung20Gy increased in 5 patients with PET findings.
CONCLUSION
The use of PET/CT in radiotherapy is helpful in defining the
tumor more precisely and possibly sparing more normal lung
tissues. It is also helpful in differentiating tumor from atelectatic
lung.