Fig. 3.

Cryoablation (CA) of oligometastatic disease from prostate carcinoma in a 52-year-old man with persistent PSA following prostatectomy and systemic therapy. ( a ) C11-choline PET/CT shows uptake within a sclerotic left 7th rib oligometastasis. CA was offered to obtain local tumor control. ( b ) Oblique axial CT image shows a cryoprobe advanced partially through the metastasis. Due to the tumor's dense sclerosis, a deeper tract could not be created with either a bone biopsy needle or handheld drill; so, the cryoprobe could not be placed deep enough to cover the posterior margin of the metastasis. ( c ) Instead, cryoprobes were placed along the margins of the rib to shape an ablation zone that would cover the entire tumor. As ice easily crosses through intact cortical and sclerotic bone, this strategy is acceptable even for a goal of local tumor control. ( d ) Intraprocedural sagittal CT image shows interstitial changes in the lung ( arrows ) deep to the metastasis along the edge of the ice ball, confirming adequate tumor coverage. ( e ) Follow-up PET/CT 1 year after ablation shows no uptake in the treated rib metastasis consistent with no residual tumor.