Prostate PSMA PET/CT Central Read — PCWG3

Quantitative PSMA PET

Three biomarkers. One scan.

Selection

SUVmean ≥10 predicts response to ¹⁷⁷Lu-PSMA.

Baseline SUVmean is the strongest quantitative predictor of PSA response and overall survival after PSMA RPT. Validated across VISION, TheraP, and the U.S. Expanded Access Program. A qualitative read cannot identify it. An SUVmax read cannot replace it.

VISION · TheraP · EAP 2026

Response

ΔPSMA-VOL drives RECIP 1.0 CR / PR / SD / PD.

≥30% decrease = PR, ≥20% increase plus new lesions = PD. Absence of PSMA uptake = CR. Everything else = SD. The categories are defined against quantitative tumor volume change at baseline and each follow-up — not against a narrative read.

RECIP 1.0 · Gafita 2022

Prognosis

TLP (Total Lesion PSMA) and TLQ (Total Lesion Quotient) — multiplicator and ratio of PSMA-VOL and SUVmean. Both are strong prognosticators of OS.

Tumor burden multiplied by PSMA expression. Volume says how much. SUVmean says how avid. The composite outperforms either parameter alone for overall survival in mCRPC across multiple cohorts — and is where the literature is moving.

Seifert 2021 · Burgard 2024 · EAP 2026

Response Criteria

Supported Response Criteria

Morphologic

CT & bone-scan endpoints

RECIST 1.1

Soft tissue lesions, nodal disease, visceral metastases.

PCWG3

Regulatory rPFS standard (bone scan + CT).

PSMA PET/CT — Response

Functional response frameworks

RECIP 1.0 (Primary)

CR / PR / SD / PD from ΔPSMA-VOL.

aPERCIST

SUVpeak-based, FDG-PERCIST adapted to PSMA.

PROMISE V2

Unified framework: PPP early disease, RECIP 1.0 for late-stage mCRPC.

PSMA PET/CT — Progression-Only

PPP — binary progression signal, not a response criterion.

RECIP 1.0 Response Categories

Quantitative category assignments

New Standard

Absence of any PSMA ligand uptake on follow-up PET.

≥30% decrease in PSMA-VOL, no new lesions.

≥20% increase in PSMA-VOL with new lesions.

Does not meet criteria for CR, PR, or PD.

PSMA-VOL = total PSMA-avid tumor volume. Quantitative volumetric measurement required for RECIP 1.0 category assignment. Qualitative reads are not sufficient.

Dual-Tracer When Discordance Matters

FDG+ / PSMA− disease is prognostic. And invisible to single-tracer imaging.

PSMA loss of expression. Neuroendocrine differentiation. Aggressive mCRPC phenotypes. These patients baseline-positive on PSMA and progress through FDG-avid, PSMA-negative lesions your PSMA PET cannot see. TheraP screened for discordance and excluded it. VISION did not screen for it. Across both, FDG+/PSMA− disease predicted shorter OS on ¹⁷⁷Lu-PSMA. FDG + PSMA on the same patient, quantified in parallel — when your protocol needs to identify discordance before it drives outcomes.

Quantitative Imaging

What We Measure in mCRPC

SUVmean

Selection Biomarker

Mean PSMA uptake across all quantified tumor.

The single strongest multivariate predictor of PSA response and overall survival after ¹⁷⁷Lu-PSMA. Threshold enrichment: SUVmean ≥10. Validated across VISION, TheraP, taxane chemotherapy, and the U.S. Expanded Access Program. Unavailable from a qualitative read.

PSMA-VOL

RECIP 1.0 Substrate

Whole-body volume of PSMA-avid disease.

Segmented across all lesions using a threshold derived from liver or blood-pool uptake. The quantitative input RECIP 1.0 requires to assign CR / PR / SD / PD. Called PSMA-VOL by Gafita and TTV in later literature — same parameter, two conventions.

ΔPSMA-VOL

RECIP 1.0 Threshold

Longitudinal percent change from baseline.

Applied directly against RECIP 1.0 cutoffs: ≥30% decrease with no new lesions = PR, ≥20% increase with new lesions = PD. Calculated per patient at each scheduled timepoint. Cannot be reconstructed retroactively from a narrative read.

TLQ

Prognostic Composite

PSMA-VOL ÷ SUVmean. Volume multiplied by expression.

Composite prognostic biomarker — tumor burden weighted by PSMA intensity. Independently prognostic for OS in mCRPC across multiple cohorts. Directly analogous to TLG in FDG-PET. Stable across software platforms and reconstructions.

Seifert 2021 · Burgard 2024 · Kimura 2026

PSMA PET/CT — segmented MTV (PSMA-VOL annotation)

PSMA-VOL — Segmented MTV

PSMA PET/CT — Quantitative RECIP 1.0 Read

PSMA-VOL quantified per patient. RECIP 1.0 categories assigned at each timepoint.

Full-Stack Imaging

Full-Stack Prostate Cancer Imaging

BioSUITE Platform

PSMA PET/CT QA

Tracer verification across PSMA-617, DCFPyL, and PSMA-11

Injection timing and reconstruction parameters validated against protocol

SUV normalization across scanners and timepoints

Site-by-site QA before reads begin — because SUVmean is meaningless across scanners that weren't harmonized

Advanced Analysis

Quantitative PSMA Biomarker Suite

3D segmentation of all PSMA-avid lesions

PSMA-VOL, SUVmean, ΔVOL — computed per patient at every timepoint

RECIP 1.0 thresholds applied directly

TLQ composite for prognostic stratification

Results live in BioSUITE — queryable, exportable, audit-ready. Not a PDF

Central Read

PSMA-Trained Readers. RECIP 1.0 + PCWG3 in Parallel.

Blinded reads by radiologists and nuclear medicine physicians trained specifically in PSMA PET/CT interpretation

PCWG3 morphologic criteria alongside RECIP 1.0 functional criteria — same patient, same timepoint, reconciled

Adjudication panel for discordant cases

Why Volumetryx

Why Sponsors Choose Volumetryx
for Prostate Trials

Quantification is the default

PSMA-VOL, SUVmean, and ΔVOL as the standard read — not a $500K add-on. Quantification is the substrate of every RECIP 1.0 category and every prognostic composite. Priced and delivered as the standard read — so sponsors don't discover after contracting that the biomarker they need is a change order.

PSMA-trained readers

Nuclear medicine readers with PSMA PET/CT subspecialty volume. Not generalist radiologists reading PSMA for the first time on your trial. Our readers are trained in PSMA tracer-specific uptake patterns — PSMA-617, DCFPyL, PSMA-11 — across disease states and post-treatment phenotypes. Adjudication panel for discordant reads.

Full PSMA criteria suite

RECIP 1.0, PPP, aPERCIST, PROMISE V2 — from one vendor. Morphologic criteria (RECIST 1.1, PCWG3) alongside functional PSMA criteria in parallel reads. No separate contracts for CT-based response and PET-based response. No reconciliation drift between two vendors.

Dual-tracer when protocol requires

FDG + PSMA on the same patient — quantified in parallel. For late-stage mCRPC and suspected discordance. Identification of FDG+/PSMA− disease before it drives trial outcomes. Single imaging infrastructure, two tracers, one audit trail.

Real Trial. Real Stakes.

Use Case: RECIP 1.0
in a Phase II mCRPC Trial

Phase II mCRPC trial. PSMA PET/CT at baseline and Week 12. The difference between qualitative and quantitative reads determines whether FDA accepts your imaging PFS data.

Without Volumetryx

Reads are qualitative.
RECIP 1.0 can't be assigned.

Your iCRO delivers PSMA PET/CT reports with "increased PSMA-avid burden" or "possible partial response." No MTV quantification — RECIP 1.0 CR/PR/SD/PD categories cannot be assigned at Week 12.

FDA requests clarification on imaging PFS methodology. Protocol amendment required. Six months of delay. The endpoint that was supposed to accelerate your Phase III timeline is now a liability.

Outcome: No RECIP 1.0 categories. Imaging PFS data rejected. Protocol amendment required.

With Volumetryx

PSMA MTV quantified per patient.
RECIP 1.0 assigned at Week 12.

BioSUITE runs PSMA MTV quantification in parallel with central reads. At Week 12: each patient receives a RECIP 1.0 category (CR/PR/SD/PD) based on measured ΔMTV. Data is clean, traceable, audit-ready.

Sponsor submits imaging PFS data to FDA as efficacy endpoint. The data package is complete — MTV per patient, timepoint, and response category — with full audit trail from image receipt to final read.

Outcome: RECIP 1.0 data complete. Imaging PFS endpoint accepted. Phase III design on track.

RECIP 1.0 is not the
whole story.
Quantification is.

Three biomarkers. One scan.

SUVmean ≥10 predicts response to ¹⁷⁷Lu-PSMA.

ΔPSMA-VOL drives RECIP 1.0 CR / PR / SD / PD.

TLP (Total Lesion PSMA) and TLQ (Total Lesion Quotient) — multiplicator and ratio of PSMA-VOL and SUVmean. Both are strong prognosticators of OS.

Supported Response Criteria

CT & bone-scan endpoints

Functional response frameworks

Quantitative category assignments

FDG+ / PSMA− disease is prognostic. And invisible to single-tracer imaging.

What We Measure in mCRPC

Full-Stack Prostate Cancer Imaging

PSMA PET/CT QA

Quantitative PSMA Biomarker Suite

PSMA-Trained Readers. RECIP 1.0 + PCWG3 in Parallel.

Why Sponsors Choose Volumetryx
for Prostate Trials

Quantification is the default

PSMA-trained readers

Full PSMA criteria suite

Dual-tracer when protocol requires

Use Case: RECIP 1.0
in a Phase II mCRPC Trial

Reads are qualitative.
RECIP 1.0 can't be assigned.

PSMA MTV quantified per patient.
RECIP 1.0 assigned at Week 12.

Your prostate trial needs
more than RECIP 1.0.

RECIP 1.0 is not the whole story. Quantification is.

Three biomarkers. One scan.

SUVmean ≥10 predicts response to 177Lu-PSMA.

ΔPSMA-VOL drives RECIP 1.0 CR / PR / SD / PD.

TLP (Total Lesion PSMA) and TLQ (Total Lesion Quotient) — multiplicator and ratio of PSMA-VOL and SUVmean. Both are strong prognosticators of OS.

Supported Response Criteria

CT & bone-scan endpoints

Functional response frameworks

Quantitative category assignments

FDG+ / PSMA− disease is prognostic. And invisible to single-tracer imaging.

What We Measure in mCRPC

Full-Stack Prostate Cancer Imaging

PSMA PET/CT QA

Quantitative PSMA Biomarker Suite

PSMA-Trained Readers. RECIP 1.0 + PCWG3 in Parallel.

Why Sponsors Choose Volumetryxfor Prostate Trials

Quantification is the default

PSMA-trained readers

Full PSMA criteria suite

Dual-tracer when protocol requires

Use Case: RECIP 1.0in a Phase II mCRPC Trial

Reads are qualitative.RECIP 1.0 can't be assigned.

PSMA MTV quantified per patient.RECIP 1.0 assigned at Week 12.

Continue exploring the imaging scope for your prostate cancer trial.

Your prostate trial needsmore than RECIP 1.0.

RECIP 1.0 is not the
whole story.
Quantification is.

SUVmean ≥10 predicts response to ¹⁷⁷Lu-PSMA.

Why Sponsors Choose Volumetryx
for Prostate Trials

Use Case: RECIP 1.0
in a Phase II mCRPC Trial

Reads are qualitative.
RECIP 1.0 can't be assigned.

PSMA MTV quantified per patient.
RECIP 1.0 assigned at Week 12.

Your prostate trial needs
more than RECIP 1.0.