Objective
Metastatic castration-resistant prostate cancer (mCRPC) is a heterogeneous disease with varying survival outcomes. This study investigated whether baseline PSMA PET/CT parameters are associated with survival and treatment response.

Methods
Sixty mCRPC patients underwent [18F]PSMA-1007 PET/CT before treatment with androgen receptor-targeted agents (ARTAs) or chemotherapy. Intensity-based parameters, volumetric parameters, metastatic sites and DmaxVox (distance between the two outermost voxels) from baseline PSMA PET/CT were collected, as well as age, Gleason score and laboratory parameters. Cox regression analysis evaluated their prognostic value for overall survival (OS). Additionally, a preliminary lesion-level analysis was done (n = 241 lesions) with lesion location and twelve radiomic features selected from previous literature. Logistic regression evaluated their association with PSMA PET/CT-based lesion progression after 3–4 months of treatment.

Results
Total tumour volume (PSMA-TV) (HR = 1.41 per doubling [1.17–1.70]), total lesion uptake (TL-PSMA) (HR = 1.40 per doubling [1.16–1.69]) and DmaxVox (HR = 1.31 per 10 cm increase [1.07–1.62]) were prognostic for OS, each independent of baseline PSA level (HR = 0.82 per doubling [0.68–0.98]), haemoglobin level (HR = 0.68 per mmol/L increase [0.49–0.95]) and line of treatment. On lesion-level, location (prostate vs bone OR = 0.23 [0.06–0.83]) and SUVmean (OR = 1.72 per doubling [1.08–2.75]) were independent prognostic markers for lesion progression, morphological and texture-based radiomic features were not.

Conclusion
Baseline PSMA PET/CT scans have prognostic value in mCRPC patients and can potentially aid in treatment decision-making. DmaxVox can serve as a simpler alternative to PSMA-TV when automated segmentation software is not available. When combined with PSMA-TV, lower PSA levels indicated worse OS, which may be a marker of tumour dedifferentiation. Further research is needed to validate these models in larger patient cohorts.

Objective: Advancing microcirculatory perfusion assessment methods is crucial for evaluating organ status during ex-vivo organ preservation and expanding the donor pool. This study demonstrates the feasibility of microcirculatory perfusion imaging in an ex-vivo liver model under normothermic machine perfusion, using two non-contact imaging techniques: laser Doppler perfusion imaging (LDPI) and laser speckle contrast imaging (LSCI).Methods and procedures: An ex-vivo porcine liver was perfused with oxygenated blood for 3 hours. Blood samples were collected every 30 minutes from the hepatic artery and portal vein to evaluate the liver’s overall status. Each of the five liver lobes was imaged every 15 minutes using both the in-house developed LDPI and wireless LSCI devices. Temporally averaged perfusion maps were analyzed to assess spatiotemporal blood flow. Then, correlations between LDPI and LSCI perfusion indices were evaluated.Results: Spatiotemporal perfusion images showed detailed superficial microcirculatory perfusion across five imaged lobes. High correlations between LDPI and LSCI indices were observed in lobes 3−5 ( R2=0.81 ), which were well-perfused. Blood lactate levels increased over time, indicating a shift in metabolic activity due to ischemia. Also, correlation of LSCI perfusion indices with pH ( R2max.=0.95 ) was observed.Conclusion: The ex-vivo liver model mimics in-vivo perfusion under controlled experimental conditions. LDPI and LSCI provide rapid, independent assessments of local microcirculatory blood flow, demonstrate a high inter-technique correlation, and reflect the overall deterioration of liver status, as evidenced by blood gas parameters.Significance: A compact, wireless LSCI system—validated against LDPI—enables non-invasive evaluation of microcirculatory status and serves as a complementary tool for assessing deep tissue viability. Clinical and Translational Impact Statement—We introduce a wireless, compact, and non-contact LSCI system (validated by LDPI) enabling microcirculatory assessment during machine perfusion, complementing deep tissue medical imaging methods and blood gas analysis to enhance organ viability evaluation and support pre-transplantation treatment decisions (Category: Pre-Clinical Research).