Bone scan detects metastases earlier than CT

Overview

64-y-old man was sent to our department for bone scan due to a staging of a prostate cancer on March 2021. Prostate cancer was diagnosed on February. Transrectal biopsy was performed, Gleason score 9 ^4,5 was determined, invasive acinar adenocarcinoma was diagnosed on histology. We performed a scintigraphy 3 hours after injection of 800 MBq of ^99mTc-HDP using a gamma camera Optima with a LEHR collimator. We detected multiple foci of increased bone metabolic turnover on a whole-body and SPECT bone scan. (Fig. 1A) SPECT/ldCT more precisely localized one focus to the right half of L1 vertebral body. (Fig. 2A) The bone structure was normal at this location on a corresponding ldCT scan. (Fig. 2B) No prostatectomy was indicated due to a clinical situation; antiandrogen hormonal therapy  was started (Zoladex) together with treatment with phosphonates (Zometa). The patient was sent to a follow-up scan, it was performed on December of the same year. Progression was evident on this scan. (Fig. 1B) There was a new osteosclerotic lesion on the corresponding ldCT at the site of increased metabolic turnover (Fig. 3A) which was scintigraphically the same as on March. (Fig. 3B) Our experience, thus, confirm earlier detection of bone metastases in comparison to radiological procedures, not only using X-ray, but also using CT.

Keywords:

bone scan – bone metastases – CT – time of detection – X-ray