Abstract
Objective Technetium-99m labeled prostate-specific membrane antigen (PSMA) single-photon emission computed tomography/computed tomography (SPECT/CT) is a suitable alternative to prostate-specific membrane antigen-positron emission tomography (PSMA-PET) imaging. However, the availability of SPECT/CT in many developing countries is limited.
Materials and Methods To evaluate the utility of planar 99mTc-PSMA in the absence of SPECT/CT, we compared planar 99mTc-PSMA and routine bone scan imaging in low-, intermediate-, and high-risk prostate cancer in five patients with histologically confirmed prostate cancer who had both scans within a period of less than 4 days. The mean age of patients was 66.8 ± 5.24, and the median prostate-specific antigen level was 175 ng/mL (range: 0–778 ng/mL).
Results Planar 99mTc-PSMA scan provided no additional benefit over bone scans in the low-risk prostate cancer cases. In the cases with intermediate-risk prostate cancers, planar 99mTc-PSMA indicated complete and partial response to treatment in oligometastatic and widespread metastatic disease, respectively. In one patient with high-risk prostate cancer, planar 99mTc-PSMA detected additional skeletal lesions that were not seen on bone scan.
Conclusion In the absence of SPECT/CT, planar 99mTc-PSMA was useful for confirming extent of disease in treated intermediate- and high-risk prostate cancer. It showed little value in low-risk prostate cancer, especially when bone scan is normal. It was particularly useful for treatment response assessment in oligometastatic disease, and its utility should be further explored.
Keywords
planar
99mTc HYNIC PSMA - bone scan - equivocal scans - SPECT
