# Total-body PET for personalised radioligand dosing

Source: https://onco.cc/ideas/idea-total-body-pet-dosimetry/  
OnCo record `idea-total-body-pet-dosimetry` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Ultra-sensitive whole-body scanners can measure exactly where a radioactive drug goes at tiny tracer doses, allowing each patient's therapeutic dose to be tailored.

## Summary

Radioligand therapy is given at fixed activity despite wide variation in tumour and kidney dose, so this idea uses ultra-sensitive total-body PET with 44Sc- or 89Zr-labelled analogues to measure each patient's pharmacokinetics before treatment and tailor the therapeutic dose. Dosimetry-guided prescription of 177Lu-PSMA is expected to raise tumour absorbed dose and response without exceeding kidney and marrow limits. Personalised dosimetry is established in radioiodine and SIRT, and total-body scanners from United Imaging and Siemens Healthineers remove the imaging-time and dose barriers. The test is a randomised trial of dosimetry-guided versus fixed-dose Pluvicto in prostate cancer with PSA50 and rPFS endpoints. At early-clinical maturity it addresses the bottleneck Wrong doses.

## Fields

- Kind: Idea
- Last checked: 2026-09-04
- Hypothesis: Dosimetry-guided activity prescription for 177Lu-PSMA increases tumour absorbed dose and response without exceeding kidney and marrow limits, compared with fixed 7.4 GBq.
- Rationale: Established in radioiodine and SIRT; total-body PET removes the imaging-time and dose barriers to pre-therapy dosimetry.
- Proposed test: Randomised dosimetry-guided vs fixed-dose Pluvicto trial with PSA50 and rPFS endpoints.
- Maturity: early-clinical

## Sources

- VISION: lutetium-177 PSMA-617 radioligand therapy extends survival in advanced prostate cancer (New England Journal of Medicine 2021): https://doi.org/10.1056/NEJMoa2107322

## Connected records

- cancers: [Prostate cancer](https://onco.cc/cancers/prostate/)
- technologies: [PET/CT](https://onco.cc/technologies/pet-ct/), [Radioligand therapy (beta emitters)](https://onco.cc/technologies/radioligand-therapy/), [SPECT & bone scan](https://onco.cc/technologies/spect/)
- drugs: [Lutetium-177 vipivotide tetraxetan](https://onco.cc/drugs/pluvicto/)
- companies: [Siemens Healthineers](https://onco.cc/companies/siemens-healthineers/), [United Imaging](https://onco.cc/companies/united-imaging/)
- terms: [Dosimetry](https://onco.cc/terms/dosimetry/)
- trials: [PSMAddition](https://onco.cc/trials/psmaddition/), [PSMAfore](https://onco.cc/trials/psmafore/), [Study of Lutetium (177Lu) Vipivotide Tetraxetan in mCRPC Participants With Moderately and Severely Impaired and With Normal Renal Function](https://onco.cc/trials/nct06004661/), [TheraP (ANZUP 1603)](https://onco.cc/trials/therap/), [VISION](https://onco.cc/trials/vision/)
- key papers: [Lutetium-177 vipivotide tetraxetan for treating PSMA-positive hormone-relapsed metastatic prostate cancer after 2 or more treatments](https://onco.cc/key-papers/paper-lutetium-177-vipivotide-tetrax-prostate-journal-2023/), [Sequencing of Radium-223 and Lutetium-177 Vipivotide Tetraxetan: Maximizing the Benefit of Systemic Targeted Radiation Therapy in Metastatic Castration-Resistant Prostate Cancer](https://onco.cc/key-papers/paper-lutetium-177-vipivotide-tetrax-prostate-oncol-ther-2025/)
- bottlenecks: [Wrong doses](https://onco.cc/bottlenecks/b-dose-optimisation/)
- ideas: [Qualify PSMA PET tumour volume as a validated imaging biomarker](https://onco.cc/ideas/idea-tr2-psma-volume-qualification/)

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