Excellent Long-Term Results of an Austin Moore Hemiarthroplasty After Half a Century: A Case Report.

CASE: We present the unique case of a 73-year-old man who was treated 50 years ago with a hemiarthroplasty (HA) for avascular necrosis after a femoral neck fracture (FNF) of his left hip and who has developed only mild osteoarthritis since and has reported satisfactory clinical and functional outcomes with no acetabular erosion. CONCLUSION: HA for FNFs can provide durable long-term results and can, therefore, be considered as an option in the treatment of FNFs in younger patients. We describe a case with good results after 50 years, which, to our knowledge, is the longest reported follow-up of HA.

The Impact of Peptide Amount on Tumor Uptake to Assess PSMA Receptor Saturation on 68Ga-PSMA-11 PET/CT in Patients with Primary Prostate Cancer.

68Ga-labeled prostate-specific membrane antigen (PSMA) is often produced on-site, where usually a fixed amount of peptide is conjugated to the generator eluate. However, fluctuations in specific activity might influence tracer distribution and tumor accumulation. Therefore, our aim was to investigate the potential effect of varying the administered peptide amount on 68Ga-PSMA-11 uptake in tumors using PET/CT in patients with primary prostate cancer (PCa). Additionally, the impact of tumor volume on this potential effect and on accumulation in reference organs was assessed. Methods: The imaging data of 362 men with primary PCa who underwent 68Ga-PSMA-11 PET/CT were retrospectively included. Scans were quantified for normal tissue and primary tumors. Patients were divided into 3 groups based on their tumor volume. Correlation and multivariable linear regression analyses were performed. Results: The median index lesion volume was 9.50 cm3 (range, 0.064-174 cm3). Groups were based on quartiles of prostatic lesion volume: ≤4.11 cm3 (group 1), 4.11-20.6 cm3 (group 2), and ≥20.6 cm3 (group 3). No correlation was found between administered peptide amount and tumor uptake (SUVmean or SUVpeak) for any group, except for a significant correlation for SUVmean in the first group (P = 0.008). Linear regression analysis supported these findings. Conclusion: The amount of administered peptide had no evident effect on 68Ga-PSMA-11 uptake in tumors, except for a significant positive correlation between administered peptide amount and tumor SUVmean for group 1. The findings imply that no receptor saturation occurs in men with primary PCa at peptide levels of about 2.5 µg.

Cerenkov Luminescence Imaging in Prostate Cancer: Not the Only Light That Shines.

Cerenkov luminescence imaging (CLI) is a novel imaging technology that might have the ability to assess surgical margins intraoperatively during prostatectomy using 68Ga-prostate-specific membrane antigen (68Ga-PSMA-11). This study evaluated the accuracy of CLI compared with histopathology and, as an exploratory objective, investigated the characteristics of the identified chemiluminescence signal. Methods: After intravenous injection of a mean 68Ga-PSMA-11 activity of 69 MBq intraoperatively, all excised specimens were imaged with CLI. Areas of increased signal were marked for histopathologic comparison and scored for the likelihood of being a positive surgical margin (PSM) using a 5-point Likert scale. In addition, the chemiluminescence signal was investigated in 3 radioactive and 3 nonradioactive specimens using CLI. Results: In 15 patients, the agreement between CLI and histopathology was 60%; this improved to 83% when including close surgical margins (≤1 mm). In 6 hot spots, CLI correctly identified PSMs on histopathology, located at the apex and mid prostate. In all 15 patients, an increased signal at the prostate base was observed, without the presence of the primary tumor in this area in 8 patients. This chemiluminescence signal was also observed in nonradioactive prostate specimens, with a half-life of 48 ± 11 min. The chemiluminescence hampered the visual interpretation of 4 PSMs at the base. Conclusion: CLI was able to correctly identify margin status, including close margins, in 83% of the cases. The presence of a diathermy-induced chemiluminescent signal hampered image interpretation, especially at the base of the prostate. In the current form, CLI is most applicable to detect PSMs and close margins in the apex and mid prostate.

A DROP-IN beta probe for robot-assisted 68Ga-PSMA radioguided surgery: first ex vivo technology evaluation using prostate cancer specimens.

BACKGROUND: Recently, a flexible DROP-IN gamma-probe was introduced for robot-assisted radioguided surgery, using traditional low-energy SPECT-isotopes. In parallel, a novel approach to achieve sensitive radioguidance using beta-emitting PET isotopes has been proposed. Integration of these two concepts would allow to exploit the use of PET tracers during robot-assisted tumor-receptor-targeted. In this study, we have engineered and validated the performance of a novel DROP-IN beta particle (DROP-INß) detector. METHODS: Seven prostate cancer patients with PSMA-PET positive tumors received an additional intraoperative injection of ~ 70 MBq 68Ga-PSMA-11, followed by robot-assisted prostatectomy and extended pelvic lymph node dissection. The surgical specimens from these procedures were used to validate the performance of our DROP-INß probe prototype, which merged a scintillating detector with a housing optimized for a 12-mm trocar and prograsp instruments. RESULTS: After optimization of the detector and probe housing via Monte Carlo simulations, the resulting DROP-INß probe prototype was tested in a robotic setting. In the ex vivo setting, the probe-positioned by the robot-was able to identify 68Ga-PSMA-11 containing hot-spots in the surgical specimens: signal-to-background (S/B) was > 5 when pathology confirmed that the tumor was located < 1 mm below the specimen surface. 68Ga-PSMA-11 containing (and PET positive) lymph nodes, as found in two patients, were also confirmed with the DROP-INß probe (S/B > 3). The rotational freedom of the DROP-IN design and the ability to manipulate the probe with the prograsp tool allowed the surgeon to perform autonomous beta-tracing. CONCLUSIONS: This study demonstrates the feasibility of beta-radioguided surgery in a robotic context by means of a DROP-INß detector. When translated to an in vivo setting in the future, this technique could provide a valuable tool in detecting tumor remnants on the prostate surface and in confirmation of PSMA-PET positive lymph nodes.