Original Article 391 Vol. 18, No. 5, 2004 Annals of Nuclear Medicine Vol. 18, No. 5, 391–397, 2004 ORIGINAL ARTICLE Received December 24, 2003, revision accepted March 22, 2004. For reprint contact: Emel Ceylan Gunay, M.D., Hacettepe University Faculty of Medicine, Department of Nuclear Medi- cine, 06100 Sihhiye/Ankara, TURKEY. E-mail: emelc@hacettepe.edu.tr INTRODUCTION GALLIUM SCANNING has an important role in the evaluation of lymphoma patients following chemotherapy or radio- therapy since other radiographic modalities such as com- puterized tomography (CT) have limitations in differenti- ating fibrosis and active residual disease after treatment. On the other hand, there are some points to be carefully evaluated when interpreting Ga-67 images following therapy. One of these is positive lung hilar Ga-67 uptake which might be either due to residual/recurrent active disease or because of a benign inflammatory response in the hilum which might be attributed to a treatment effect. Differentiating the etiology of hilar Ga-67 uptake (whether it is benign or malignant) would result in a change in the clinical management of the patients. The purpose of this retrospective study is to evaluate the scintigraphic patterns including symmetry/asymmetry and the intensity of hilar Ga-67 uptake following chemo- therapy and to investigate their relationship with the etiology (benign versus malignant) of the hilar involve- ment. MATERIALS AND METHODS Patients We retrospectively reviewed Ga-67 studies of patients with pathologically confirmed diagnosis of Hodgkin’s disease (HD) or non-Hodgkin’s lymphoma (NHL) treated between June 1996 and December 2002 in our institution. One hundred sixty-one patients who had Ga-67 study after receiving at least 3 cycles of chemotherapy regimen were included in the study majority of the patients had more than one Ga-67 scan. The first Ga-67 scan following chemotherapy was the primary scintigraphy on which scintigraphic characteristics of lung hilar uptake has been investigated. There was at least a 3-week interval be- tween the last chemotherapy administration and Ga-67 injection, except for 3 patients with 7–10 days interval. Both whole body and thorax single photon emission computed tomography (SPECT) Ga-67 images of the patients were examined. The following information on each patient was retrospectively obtained from the Lung hilar Ga-67 uptake in patients with lymphoma following chemotherapy ・ Emel Ceylan GUNAY,* Bilge Volkan SALANCI,* Ibrahim BARISTA** and Biray CANER* Departments of *Nuclear Medicine, and **Medical Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey Scintigraphic characteristics of lung hilar Ga-67 uptake (HU) and their relationship with the etiology (benign vs. malignant) of the hilar lesions in lymphoma patients following chemotherapy were retrospectively investigated. A total of 161 lymphoma patients were included in the study. The presence/absence of HU and if present, symmetry/asymmetry and intensity of HU (on the basis of a 3 scale grading system) were visually and semiquantitatively assessed on transaxial sections of thorax Ga-67 SPECT. By drawing ROIs over right and left hilum, asymmetry index (AI%) was also calculated. HU was categorized as benign or malignant depending on the radiological correlation and clinical follow-up. In the malignant group, the majority of patients (85.7%) had grade 2 or grade 3 uptake and all had asymmetric pattern. However, in the benign group, grade 1 uptake was more common (66%) and was mainly symmetric (94.6%) in appearance. AI% in the malignant group (73.7 ± 36.6) was significantly higher than in the benign group (5.7 ± 4.9) confirming the marked asymmetry in malignant patients. Key words: Ga-67 scan, hilar uptake, lymphoma, scintigraphy, asymmetry index