# Radioligand dosimetry

Source: https://onco.cc/technologies/radioligand-dosimetry/  
OnCo record `radioligand-dosimetry` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Measuring, from scans taken after each dose, how much radiation a radioligand actually delivers to the tumour and to kidneys and marrow, so treatment can be personalised.

## Summary

Radioligand therapies are mostly given at fixed activities, unlike external radiotherapy which is planned to a dose. Post-treatment SPECT or PET imaging at several time points lets physicists calculate absorbed doses to tumours and organs at risk, and trials are testing dose escalation guided by kidney and marrow dosimetry. European regulation now expects dosimetry to be available, and software and imaging protocols are being standardised to make it routine.

## Fields

- Kind: Technology
- Status: established
- Last checked: 2026-09-04
- Principle: Serial quantitative imaging after administration measures activity in organs over time; time-integrated activity and dose kernels give absorbed dose per organ, which guides subsequent cycles.
- Strengths: Personalises activity to each patient; Explains variable toxicity and response; Required by European regulation
- Limitations: Extra imaging visits; Methodological variation between centres; Prospective outcome evidence still limited

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Dosimetry
- Wikipedia: https://en.wikipedia.org/wiki/Dosimetry

## Connected records

- fronts: [Imaging](https://onco.cc/fronts/imaging/), [Radiopharmaceuticals & Theranostics](https://onco.cc/fronts/radiopharma/)
- technologies: [Lutetium-177 radioligand therapy](https://onco.cc/technologies/lu177-radioligand-therapy/), [Radioligand therapy (beta emitters)](https://onco.cc/technologies/radioligand-therapy/)

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