Research on Scintimetric Characterization of Skeletal Hotspots by Dr. V. Siva’s Retention Ratio in a Diagnostic Referral Center

Aim: This study aims to document the utility of Scintimetric Characterization of the Skeletal Hot Spots seen in the Bone Scans done in this referral center during 2016-2017, in differentiating metastatic and non-metastatic lesions.

Materials and Methods: The study group consists of 59 patients referred for metastatic evaluation and non-specific bone complaints to our center. The whole body bone scan was done 3hrs after the intravenous injection of 15 to 25 mCi of Tc99m MDP using GE Millenium Gamma Camera. The 24hr whole body bone scan was repeated in all those who had focal hot spots in their scans and who accepted voluntarily with the consent of the referring physician. The counts in the focal hot spots at 3 and 24 hr bone scan images were calculated using the region ratio count protocol. The Dr. V. Siva’s Retention Ratio was calculated by dividing the3hr counts by the 24 hr counts in the focal hotspots. The values of metastatic and non- metastatic groups were tabulated and analyzed.

Results: In our series 35/59 (59%) scans were negative and did not show any focal changes. 24/59 (41%) scans showed focal changes in the form of hot spots. Out of the total 69 hot spots analyzed 31 (45%) had the value of 13.07 ± 1.02 indicating metastatic nature and 38 (55%) had the value of 6.07 ± 0.62 confirming the benign nature of the lesions. Thus the metastatic group had the mean value which is almost twice that of the benign group. The statistical evaluation confirmed the significant difference between the two groups.

Conclusion: It can be concluded that the Scintimetric characterization of the focal hot spots by Dr. V. Siva’s retention ratio effectively provides useful means to differentiate between the metastatic and non-metastatic lesions in the tertiary referral diagnostic center as well.