The improvement of comprehensive multi-modality treatment and radiotherapy (RT) technology has resulted in an improved survival rate of head and neck malignancies within recent decades. As survival increases, late toxicity from cancer therapy becomes a larger burden. Radiation induced vascular injury following RT is a recognized complication of radiotherapy. Diagnosis of vascular changes predominately relies on non-invasive imaging techniques. Doppler ultrasound assessment has been proven as a good indicator of diffuse atherosclerotic disease and a significant predictor of future vascular events. New opportunities are provided by the recent introduction of the hybrid PET/MRI scanners for investigating the synergistic effect of these two modalities without the challenge of image co-registration. It has been shown that the PET system integrated with the MRI scanner performs the same as the PET portion of a PET/CT for various cancers and cardiovascular indications. MRI allows better delineation of the carotid artery and atherosclerotic plaque when compared with CT due to the superior soft tissue contrast. The PET/MRI system acquires the PET and MRI simultaneously allowing for perfect alignment between the 2 sets of images, when compared with the sequential acquisition in PET/CT where minor head movements can cause misalignment. There is evidence in the literature that 68-Ga DOTA-TATE PET-imaging can serve as a surrogate marker for evidence of invasion into the vessel wall and thereby possibly detects early, developing atherosclerotic plaque. Thus, combined PET and MR with 68-Ga DOTA-TATE should be a promising imaging tool to screen and characterize patients at risk for radiation induced carotid injury.

In this study, DOTATATE-PET/MR will be performed in up to 60 patients with a history of radiation therapy for head and neck squamous cell carcinoma over 2 years.

Inclusion Criteria:

• previously treated with radiation for head and neck malignancy;
• Age Group: ≥30 years;
• Patients who have no contraindications to PET/MRI;
• No allergy to contrast agents.

Exclusion Criteria:

• Pregnant females;
• Age group: < 30 years;
• Allergy to MR contrast agents;
• Pacemakers/ICD/Claustrophobic patients.