ABSTRACT
Magnetic resonance imaging (MRI)-guided transurethral ultrasound therapy is a potential minimally invasive treatment for localized prostate cancer offering precise targeting of tissue within the gland, short treatment times, and the capability to quantify the spatial heating pattern delivered during therapy. A significant challenge in MRI-guided ultrasound therapy is the design and construction of MRI-compatible equipment capable of operation in a closed-bore MR imager. We describe a prototype system developed for MRI-guided transurethral ultrasound therapy and characterize the performance of the different components including the heating applicator design, rotational motor, and radio frequency electronics. The ultrasound heating applicator described in this study incorporates a planar transducer and is capable of producing high intensity ultrasound energy in a localized region of tissue. Results demonstrated that the heating applicator exhibits excellent MRI-compatibility, enabling precise MR temperature measurements to be acquired as close as 6 mm from the device. Simultaneous imaging and rotational motion was also possible during treatment using a motor based on piezoelectric actuators. Heating experiments performed in both phantoms and in a canine model with the prototype system verified the capability to perform simultaneous MR imaging and therapy delivery with this system. Real-time control over therapy using MR temperature measurements acquired during heating can be implemented to achieve precise patterns of thermal damage within the prostate gland. The technical feasibility of using the system developed in this study for MRI-guided transurethral ultrasound therapy in a closed-bore MR imager has been demonstrated.
Subject(s)
Image Enhancement/instrumentation , Magnetic Resonance Imaging, Interventional/instrumentation , Prostatic Neoplasms/diagnosis , Prostatic Neoplasms/therapy , Ultrasonic Therapy/instrumentation , Urethra/pathology , Equipment Design , Equipment Failure Analysis , Humans , Image Enhancement/methods , Magnetic Resonance Imaging, Interventional/methods , Male , Phantoms, Imaging , Reproducibility of Results , Rotation , Sensitivity and Specificity , Ultrasonic Therapy/methodsABSTRACT
OBJECTIVE: To develop burn prevention strategies for the elderly population in Hong Kong using a novel epidemiological approach. METHODS: Medical records of all patients aged 60 or above who were admitted to our hospital in a 6-year period were reviewed and demographic data, injury characteristics, details of management and outcome were obtained. Selected interviews were undertaken to determine the exact mechanisms of injury and further details of the medical and social background. RESULTS: Fifty-nine elderly patients were identified from the medical records with under half (42%) aged 75 and above. Male to female ratio was 1:1.68. Three-quarters of the injuries occurred at home, principally in the kitchen and bathroom. Two-thirds of the burns were scalds. Forty-eight percent of the admitted patients had surgery. Thirty-seven patients (or next of kin) were interviewed further. Of the subgroup only 12% had received appropriate first aid and 27% had treatment delayed for over 24 h before seeking medical help. The majority of patients had little or no formal education and one quarter were living alone. CONCLUSION: We identified common scenarios of elderly burns which could be used to focus prevention strategies.