Gallium-68 prostate-specific membrane antigen positron emission tomography/computed tomography compared with diagnostic computed tomography in relapsed prostate cancer.

The aim of this study was to evaluate if prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) has a higher detection rate compared to standard contrast CT imaging for patients with a rising prostate-specific antigen (PSA) following definitive treatment (i.e., curative radical prostatectomy, radiotherapy, and brachytherapy) for prostate cancer in a private hospital setting. A retrospective single-site clinical audit was conducted on 150 PSMA PET/CT scans done for patients with a rising PSA after definitive treatment for prostate cancer. All studies were performed using I and T Ga-68 PSMA produced on a Scintomics radiopharmaceutical unit (Munich). All scans were performed on a GE 710 PET/CT scanner. All studies were compared to standard CT and other imaging. Of the 150 patients who had a 68Gallium (Ga)-PSMA PET/CT for a rise in their PSA levels, 102/150 (68%) of patients had PSMA-avid scans compared to the conventional imaging group which had an overall detection rate of 42% (63/150). The rates of detection were 100%, 90%, 92%, 67%, and 25% at PSA levels of >10 µg/L, 5-10 µg/L, >1.5 µg/L, 0.5-1.5 µg/L, and <0.5 µg/L, respectively. PSMA PET/CT also solely picked up 39/102 (38%) of prostate cancer relapses compared to the conventional imaging group. In our study of 150 patients with biochemical recurrence of prostate cancer, 68Ga-PSMA PET/CT demonstrated a superior detection rate (P < 0.05) compared to conventional imaging, including patients with low PSA levels (<0.5 µg/L).

The role of 68Ga-PSMA-I&T PET/CT in the pretreatment staging of primary prostate cancer.

OBJECTIVES: This retrospective study aimed to evaluate the role of Ga-PSMA-I&T PET/CT in the primary staging of newly diagnosed prostate cancer (PCa), with a focus on the detection of metastatic nodal disease. Correlation of the rate of detection of metastatic disease by Ga-PSMA-I&T PET/CT with the Gleason score (GS) and serum prostate-specific antigen (PSA) was performed to determine the GS and PSA criteria defining patients who would benefit from Ga-PSMA-I&T PET/CT imaging for staging, risk stratification and therapy optimization. PATIENTS AND METHODS: Patient data and images from 70 patients with a recent diagnosis of prostate cancer who had undergone Ga-PSMA-I&T PET/CT were analysed retrospectively. Data and images were analysed for the rate of detection of primary and metastatic PCa, and correlation with PSA and GS. RESULTS: The rate of detection of primary tumour by Ga-PSMA-I&T for patients with serum PSA less than 5 ng/ml was 73%. The corresponding rate was 90% for patients with PSA 5-10 ng/ml and 97% for patients with PSA more than 10 ng/ml. Metastatic PCa and/or infiltrative disease was detected in 24/70 study patients in total: 1/11 patients with PSA less than 5 ng/ml and 23/59 patients with serum PSA at least 5 ng/ml. The rate of detection of metastatic PCa was greater in patients with GS 9 or more (48%) relative to those with GS 8 (32%) or GS ≤7 (18%). CONCLUSION: A role for Ga-PSMA-I&T PET/CT in primary PCa staging of high-grade disease (GS 8 or more and PSA >10 ng/ml) has been shown. There was a low rate of detection of PSMA-avid metastases in low-grade disease (GS 7 or less and PSA <5 ng/ml), suggesting that there is a limited role for this modality in such cases.

Laxative Related Primary Hyperphosphatemic Tumoral Calcinosis Identified by Bone Scintigraphy.

We describe a case of a 40-year-old female patient presenting with tumor calcinosis where hypertrophic pulmonary osteoarthropathy (HPOA) was suspected given her extensive history of malignancy. Plain X-rays did not show reveal the typical periarticular calcification but did show appearances consistent with HPOA. Bone scintigraphy with (99m)Tc-methylene diphosphonate (MDP) is a sensitive investigation in the detection of hypertrophic osteoarthopathy but did not show findings characteristics of HPOA like bilateral symmetrical increased uptake of the radiopharmaceutical along the cortical margins of the long bones. The final diagnosis of tumor calcinosis was only made after low dose computerized tomography chest showed a moderated sized amorphous calcified cluster in the apical segment of the right upper lobe consistent. In conclusion, bone scintigraphy continues to be a useful investigation for both common and rare conditions like tumor calcinosis. The unusual three phase bone scan finding of diffuse activity throughout both lung fields, which turned to out to be tumoral calcinosis is highlighted in this case.