# HER2 PET

Source: https://onco.cc/technologies/her2-pet/  
OnCo record `her2-pet` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

HER2 PET is a PET scan using radiolabelled trastuzumab or smaller HER2 binders to map HER2 across all metastases at once.

## Summary

HER2 PET images HER2 across every metastasis at once using a radiolabelled HER2 binder, either 89Zr-trastuzumab or smaller 68Ga- and 18F-labelled affibodies and nanobodies such as 68Ga-ABY-025 and 18F-GE-226. The result is a whole-body receptor map rather than a single biopsy, which matters because HER2 expression varies between lesions. The ZEPHIR and IMPACT trials studied these tracers, and uptake was predictive of response to T-DM1. It is most useful in heterogeneous HER2-low disease, where one biopsy may be unrepresentative and HER2-directed ADCs now have indications. Studied since 2010, it is not yet approved; trials have been small, and full-antibody tracers need days between injection and imaging, which smaller binders aim to shorten. It shows how much HER2 each tumour deposit carries without a needle.

## Fields

- Kind: Technology
- Status: phase-2
- Last checked: 2026-09-04
- Principle: Radiolabelled HER2 binder; whole-body receptor map.
- Since: 2010
- Strengths: Captures inter-lesion heterogeneity; Non-invasive re-assessment
- Limitations: Not approved; small trials; Antibody tracers need days

## Sources

- Gebhart et al., ZEPHIR: molecular imaging of heterogeneity in advanced HER2-positive breast cancer with 89Zr-trastuzumab PET (Annals of Oncology 2016): https://doi.org/10.1093/annonc/mdv577

## Connected records

- cancers: [Early HER2-positive breast cancer](https://onco.cc/cancers/her2-positive-early-breast-cancer/), [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/), [HER2-low and HER2-ultralow metastatic breast cancer](https://onco.cc/cancers/her2-low-metastatic-breast-cancer/), [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/), [HER2-positive breast cancer with brain metastases](https://onco.cc/cancers/her2-positive-breast-brain-metastases/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/)
- fronts: [Antibody-Drug Conjugates](https://onco.cc/fronts/adcs/), [Imaging](https://onco.cc/fronts/imaging/)
- technologies: [FES PET (oestrogen receptor imaging)](https://onco.cc/technologies/fes-pet/), [Immuno-PET](https://onco.cc/technologies/immuno-pet/), [PET (positron emission tomography)](https://onco.cc/technologies/pet/)
- targets: [HER2](https://onco.cc/targets/her2/)
- trials: [[68Ga]Ga-ABY-025 PET for Quantification of HER2-status in Solid Tumors](https://onco.cc/trials/nct05619016/), [HER2 Targeted Molecular Imaging in mBC and Other Metastatic Solid Carcinomas Using 68Ga-ABS011](https://onco.cc/trials/nct06369831/), [Optimization of Dynamic Neoadjuvant Therapy Strategies for HER2-Positive Breast Cancer Based on HER2-PET/CT Molecular Imaging](https://onco.cc/trials/nct07527806/)
- key papers: [Molecular imaging as a tool to investigate heterogeneity of advanced HER2-positive breast cancer and to predict patient outcome under trastuzumab emtansine (T-DM1): the ZEPHIR trial](https://onco.cc/key-papers/paper-gebhart-ann-oncol/)
- roadmaps: [ADC roadmap: from Mylotarg to bispecific and dual-payload ADCs](https://onco.cc/roadmaps/adc-generations/), [Molecular imaging roadmap: FDG → PSMA → FAP → antigen and immune PET](https://onco.cc/roadmaps/molecular-imaging-roadmap/)
- people: [Jason S. Lewis](https://onco.cc/people/jason-lewis/), [Shaoli Song](https://onco.cc/people/song-shaoli/)
- bottlenecks: [Biomarkers are not validated or standardised](https://onco.cc/bottlenecks/b-biomarker-validation/)

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