Radiography, ^99mTc-HDP, and ¹¹¹in labeled vitamin B ₁₂ SPECT of canine osteosarcoma: A comparative study

The objective of this article was to compare radiography, planar bone scintigraphy, and single-photon emission computed tomography (SPECT) to determine the size of osteosarcomas in long bones of dogs. Ten dogs with osteosarcoma in six radii, two humeri, one tibia, and one ulna were evaluated. Macroslides, mediolateral radiographs, planar scintigrams, and sagittal images from SPECT scans were used to obtain measurements. On the scintigraphic images, the edges of the tumor were established using the activity profile imaging tool. The radiographic magnification was factored. The mean percentage of tumor size overestimation was 9.29% on mediolateral radiographs, 5.35% on planar scintigrams, and 33.25% on SPECT images. The correlation coefficient adjusted for sample size was significantly higher (P<0.01) for technetium 99m ( ^99mTc) hydroxyethylene diphosphonate (HDP) (75.5%) and radiography (61.3%) compared with indium 111-vitamin B ₁₂ (28.3%). The correlation coefficient for ^99mTc-HDP was higher than that obtained for radiographs; however, statistical difference between the two variables was not demonstrated (P>0.05). ^99mTc bone scan is a good estimator of intramedullary size of osteosarcoma in long bones when the activity profile tool to determine the margin of the tumor is used.