Differentiating local recurrence from post-treatment changes on PET scans following stereotactic ablative radiotherapy (SABR) or hyperfractionation for lung tumors is challenging. We performed a prospective pilot study of 3-deoxy-3-[¹⁸F]-fluorothymidine (FLT)-PET-CT in patients with equivocal post-radiation FDG-PET-CT to assess disease recurrence. Methods: We prospectively enrolled 10 patients, 9 treated with SABR and 1 with hyperfractionated external beam radiotherapy for thoracic malignancy with subsequent equivocal follow-up FDG-PET-CT, to undergo FLT-PET-CT prior to biopsy or serial imaging. FLT-PET scans were interpreted by a radiologist with experience in reading FLT-PET-CT and blinded to the results of any subsequent biopsy or imaging. Results: Of the 10 patients enrolled, 8 were evaluable after FLT-PET-CT. Based on the FLT-PET-CT, a blinded radiologist accurately predicted disease recurrence vs. inflammatory changes in 7 patients (87.5%). The combination of higher lesion SUV_max and higher ratio of lesion SUV_max to SUV_max of mediastinal blood pool was indicative of recurrence. Qualitative assessment of increased degree of focality of the lesion also appears to be indicative of disease recurrence. Conclusion: Adjunctive FLT-PET-CT imaging can complement FDG-PET-CT scan in distinguishing post-treatment radiation changes from disease recurrence in thoracic malignancies. These findings support the investigation of FLT-PET-CT in a larger prospective study.

Purpose

The Audio-Visual Assisted Therapeutic Ambience in Radiotherapy (AVATAR) system was the first published radiation therapy (RT)-compatible system to reduce the need for pediatric anesthesia through video-based distraction. We evaluated the feasibility of AVATAR implementation and effects on anesthesia use, quality of life, and anxiety in a multicenter pediatric trial.

Methods and materials

Pediatric patients 3 to 10 years of age preparing to undergo RT at 10 institutions were prospectively enrolled. Children able to undergo at least 1 fraction of RT using AVATAR without anesthesia were considered successful (S). Patients requiring anesthesia for their entire treatment course were nonsuccessful (NS). The PedsQL3.0 Cancer Module (PedsQL) survey assessed quality of life and was administered to the patient and guardian at RT simulation, midway through RT, and at final treatment. The modified Yale Preoperative Anxiety Scale (mYPAS) assessed anxiety and was performed at the same 3 time points. Success was evaluated using the χ² test. PedsQL and mYPAS scores were assessed using mixed effects models with time points evaluated as fixed effects and a random intercept on the subject.

Results

Eighty-one children were included; median age was 7 years. AVATAR was successful at all 10 institutions and with photon and proton RT. There were 63 (78%) S patients; anesthesia was avoided for a median of 20 fractions per patient. Success differed by age (P = .04) and private versus public insurance (P < .001). Both patient (P = .008) and parent (P = .006) PedsQL scores significantly improved over the course of RT for patients aged 5 to 7. Anxiety in the treatment room decreased for both S and NS patients over RT course (P < .001), by age (P < .001), and by S versus NS patients (P < .001).

Conclusions

In this 10-center prospective trial, anesthesia avoidance with AVATAR was 78% in children aged 3 to 10 years, higher than among age-matched historical controls (49%; P < .001). AVATAR implementation is feasible across multiple institutions and should be further studied and made available to patients who may benefit from video-based distraction.