SKELETAL SCINTIGRAPHY WITH TECHNETIUM-99M-TETRAPHENYL PORPHYRIN SULFONATE FOR THE DETECTION AND DETERMINATION OF OSTEOMYELITIS IN AN ANIMAL-MODEL

This article explores the accumulation of Tc-99m-tetraphenyl porphyrin sulfonate (TPPS4) at inflammatory sites, especially osteomyelitis, an d compares the results with In-111 Cl-3 and In-111-WBC in an animal mo del. Methods: Osteomyelitis was induced in 12 New Zealand white rabbit s by injecting staphylococcus aureus in the left tibia, Three weeks la ter, radiographs confirmed the disease. Two hours later, after injecti on of 74 MBq Tc-99m-TPPS4, scintiphotos of the lower extremities were acquired and repeat scintiphotos were obtained 24 hr after injection o f 5.55 MBq In-111 Cl-3. After these studies, 24- and 48-hr scintiphoto s of the lower extremities were acquired after injecting 5.55 MBq In-1 11-labeled WBC. Results: The left tibia averaged three times the uptak e with Tc-99m-TPPS4 compared with right tibia; with In-111 Cl-3 and In -111 WBC the ratios are two times, These three radiopharmaceuticals re veal positive images, but the image quality using Tc-99m-TPPS4 is bett er, as would be expected from the more favorable physical characterist ics of Tc-99m and the higher uptake. Conclusion: The traditional combi nation of three-phase bone and Ga-67-citrate scintigraphy can be repla ced by a single injection of Tc-99m-TPPS4 with imaging as early as 2 h r, Finally, the use Tc-99m-TPPS4 should result in a substantial reduct ion in radiopharmaceutical cost.