Verification of Range Accuracy and Correlation With Clinical Toxicity Using Offline PET/CT for Hypofractionated Proton Radiotherapy in Breast Cancer

This is a single-arm, single-center, prospective observational study. It uses offline PET/CT to verify and quantify the range accuracy of hypofractionated proton radiotherapy for postoperative breast cancer. The correlation between range error and clinical toxicities (radiation pneumonitis, rib fracture) will be analyzed. A PET signal-proton range correlation model will be established using Monte Carlo simulation to provide evidence for optimizing proton therapy planning.

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Key information

Conditions

Breast Cancer Breast Diseases Breast Neoplasms Neoplasms Neoplasms by Site Skin Diseases Skin and Connective Tissue Diseases

Age range

18 year and older

Sex eligibility

Female

Study type

Observational

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Written informed consent obtained.
Female aged ≥18 years.
Pathologically confirmed breast cancer after curative surgery (breast-conserving or mastectomy) and indicated for postoperative adjuvant radiotherapy.
Scheduled to receive moderate or ultra-hypofractionated proton therapy.
KPS ≥80, expected survival >5 years.
Well-healed surgical incision without infection.
Fertile females must use contraception for ≥1 month before screening and throughout the study.

Exclusion criteria

Pregnant or lactating female.
Severe non-neoplastic medical comorbidities precluding radiotherapy.
Inability to cooperate or comply with offline PET/CT examination.

Treatment and study plan

Offline PET/CT scanning

Other

Offline PET/CT scan performed after proton therapy to verify range accuracy; no therapeutic intervention

Primary outcomes

Proton beam range accuracy verified by offline PET/CT

Time frame: During proton radiotherapy (at the time of offline PET/CT scanning)

Quantify the range accuracy of hypofractionated proton radiotherapy for breast cancer using offline PET/CT imaging
Correlation between range error and radiation pneumonitis

Time frame: Up to 24 months after completion of proton radiotherapy

Evaluate the correlation between proton range error measured by offline PET/CT and the incidence of radiation pneumonitis
Correlation between range error and rib fracture

Time frame: Up to 24 months after completion of proton radiotherapy

Evaluate the correlation between proton range error measured by offline PET/CT and the incidence of rib fracture

Secondary outcomes

Correlation between range error and lung dosimetric parameters

Time frame: During proton radiotherapy

Analyze the correlation between proton range error and lung V5, V10, V20
Correlation between range error and rib dosimetric parameters

Time frame: During proton radiotherapy

Analyze the correlation between proton range error and rib Dmax, V30
Performance of PET signal-proton range prediction model

Time frame: During proton radiotherapy

Establish and evaluate the PET signal-proton range quantitative model using Monte Carlo simulation

Sponsors and collaborators

Lead sponsor

Ruijin Hospital

Other

Registry information

Acronym: OFFLINE-PET-PR

Important dates

Study start: 2026
Primary completion: 2028
Study completion: 2028
First posted: Apr 21, 2026
Registry last updated: Apr 21, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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