A COMPARATIVE-STUDY BETWEEN PLANAR GA-67, TI-201 IMAGES, CHEST-X-RAY,AND X-RAY CT IN INOPERABLE NONSMALL CELL-CARCINOMA OF THE LUNG

Seventy patients with newly diagnosed, pathologically proven inoperabl e non-small cell lung cancer (NSCLC) had planar Ga-67, TI-201, chest x -ray, and chest CT imaging performed, Tumor/Normal tissue background ( T/B) ratio was calculated for 62 Ga-67 and 55 TI-201 scintigraphy stud ies and comparisons were made between Ga-67 and TI-201 imaging results regarding T/B ratios, site of lesion, and histologic type. The impact of the images on the initial knowledge of the extent of the tumor and on the radiotherapy (RT) planning was evaluated for each patient. For primary lesions, Ga-67 imaging results were positive in 94% (66 of 70 patients) versus 71% (50 of 70 patients) for TI-201 scans (P < 0.005) and the T/B ratio was >1.5 in 74% (46 of 62 patients) for Ga-67 versu s 36% (20 of 55 patients) for TI-201 (P < 0.0001). For centrally locat ed lesions, sensitivity for Ga-67 was 100% (53 of 53 patients) versus 74% (39 of 53 patients) for TI-201 (P < 0.0005) and the T/B ratio >1.5 in 84% (38 of 45 patients) for Ga-67 versus 38% (15 of 40 patients) f or TI-201 (P > 0.001). For peripheral lesions, sensitivity of Ga-67 wa s 76% (13 of 17 patients) versus 64% (11 of 17) for TI-201 (P > 0.05) and the T/B ratio was >1.5 in 47% (8 of 17 patients) for Ga-67 versus 33% (5 of 15 patients) for TI-201 (P < 0.05). The sensitivity of Ga-67 for squamous cell carcinoma was 92% (37 of 40 patients) versus 75% (3 0 of 40 patients) for TI-201 (P < 0.05). For adenocarcinoma Ga-67 sens itivity was 94% (15 of 16 patients) versus 69% (11 of 16 patients) for TI-201 (P < 0.05). For undifferentiated carcinoma, Ga-67 sensitivity was 100% (14 of 14 patients) versus 64% (9 of 14 patients) for TI-201 (P > 0.005). Mediastinal involvement as assessed by CT, Ga-67, and TI- 201 was present in 89%, 51%, and 10%, respectively (P < 0.0001). For d etermination of the local extent of the tumor compared to the chest x- ray, Ga-67 scintigraphy added more information in 49% (34 of 70 patien ts) versus 27% (19 of 70 patients) for TI-201 (P < 0.005). When compar ed to CT, Ga-67 scintigraphy gave additional information in 4% (3 of 7 0 patients) of the patients versus 3% (2 of 70 patients) for TI-201 im aging. For the purpose of radiation therapy planning, if based on ches t x-ray findings, Ga-67 scintigraphy was necessary for proper planning in 54% (38 of 70 patients) versus 27% (19 of 70 patients) for TI-201 imaging. If treatment planning was based on CT, Ga-67 scintigraphy add ed more Information in 19% (13 of 70 patients) versus only 3% (2 of 70 patients) for TI-201 imaging. We conclude that Ga-67 scintigraphy is more useful than TI-201 imaging In the initial evaluation of NSCLC, Bo th are inferior to x-ray CT imaging for staging purposes and determini ng the local extent of the disease. Gallium-67 scintigraphy was necess ary in some patients for proper radiation therapy treatment planning a nd adds more useful information to the x-ray CT imaging. Thallium-201 imaging did not add more information to Ga-67 scintigraphy in any pati ent.