MRI-guided radiotherapy for head and neck cancer: initial clinical experience

Purpose. To report a single-institutional experience with the use of magnetic resonance imaging (MRI)-guided radiotherapy for cancers of the head and neck. Materials and methods. Between October 2014 and October 2016, 18 patients with newly diagnosed cancers of the head and neck were prospectively enrolled on an institutional registry trial investigating the feasibility and efficacy of external-beam radiotherapy delivered using on-board MRI. All patients had biopsy-proven evidence of malignancy, measurable disease, and the ability to provide consent. None had previously received any treatment. Median dose was 70 Gy (range 54-70 Gy). MRI scans were obtained as part of an image-guided registration protocol for alignment prior to and during each treatment. Concurrent chemotherapy was administered to 14 patients (78%). Patient-reported outcomes were assessed using the University of Washington quality of life instrument. Results. Seventeen of 18 patients completed the planned intensity-modulated radiotherapy (IMRT) treatment of which 15 (83%) had a complete response and 2 (11%) had a partial response based on initial post-therapy positron emission tomography (PET) at 3 months. The 1-year estimates of progression-free survival, overall survival, and local-regional control were 95, 96, and 95%, respectively. There were no treatment-related fatalities. The incidence of grade 3+ acute toxicity was 44%. The proportion of patients rating their health-related quality of life as "very good" or "outstanding" at 6 months and 1 year after completion of radiation therapy was 60 and 70%, respectively. Conclusions. MRI-guided radiotherapy achieves clinical outcomes comparable to contemporary series reporting on IMRT for head and neck cancer (AU)

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Quality Assurance and Safety of New Technologies for Radiation Oncology.

This article reviews suggested recommendations and procedures for quality assurance and safety tests of computer-controlled medical accelerators and the associated high-tech ancillary devices such as asymmetric collimators, dynamic wedge, multileaf collimators, and on-line electronic portal imaging devices for treatment verification, and technologies such as dynamic therapy and beam intensity modulation that are just coming on line. These new technologies are likely to lead to improved therapeutic ratios through the use of conformal physical dose distributions that cannot be achieved using traditional planning, delivery, and verification methods and, at the same time, provide more complete and thorough safety systems. However, these devices are not yet fully developed and thus come with some limitations and an increased potential for patient treatment error. To insure optimum use, a rigorous quality assurance program specifically designed for these technologies must be in place and the radiation oncology team should be constantly vigilant. In addition, provision should be made to provide for increased continuing staff education in the use of these technologies and complementary safety and quality assurance devices such as a record and verify system should be considered essential.