{'fraction_non_alphanumeric': 0.03502919099249374, 'fraction_numerical': 0.007506255212677231, 'mean_word_length': 5.185567010309279, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Recurrent nasopharyngeal tumors: preliminary clinical results with interventional MR imaging--controlled laser-induced thermotherapy.

PURPOSE
To evaluate magnetic resonance (MR) imaging-controlled laser-induced thermotherapy (LITT) in the treatment of recurrent head and neck tumors.


MATERIALS AND METHODS
Six patients with recurrent nasopharyngeal tumors (squamous cell carcinoma [n = 4], pleomorphic adenoma [n = 2]) underwent LITT with local anesthesia. A 7-F introducing sheath was inserted into the center of the tumor followed by a specially designed laser emitter. Therapy was monitored on-line with MR thermometry, and the amount of necrosis was estimated with dynamic and static contrast material-enhanced sequences.


RESULTS
All procedures were well tolerated with use of local anesthesia, with no clinically relevant side effects. MR thermometry depicted up to 15-mm-diameter areas of less signal intensity near the laser tip. Coagulative necrosis was achieved in all patients (volume range, 4-28 cm3), and clinical symptoms were reduced in four.


CONCLUSION
MR imaging-controlled LITT may be a safe, minimally invasive alternative in the treatment of recurrent head and neck tumors.