OPTIMUM TREATMENT PLANNING SYSTEM FOR HIGH DOSE-RATE INTRACAVITARY THERAPY OF CARCINOMA OF THE UTERINE CERVIX

A planning system has been developed to automatically calcul ate and display the optimum source arrangement, irradiation conditions and dose distributions for patients treated for carcinoma of the uterine cervix by high dose-rate intracavitary therapy using a remote afterloading system. In our system:(1) the optimum dose distributions are defined as those obtained using source arrangements like the Manchester system, (2) to determine the optimum source arrangement and irradiation conditions similar to the Manchester system for the size and geometry of applicators in a patient, the shape of the isodose curve passing through points A in a series of isodose distributions is calculated, (3) the optimum irradiation condition is calculated to have a dose value on the isodose curve equal to the predefined dose value using quadratic programming, and (4) the optimized dose distributions for an optimum irradiation condition are automatically calculated and displayed. This opti mization can be calculated in about 2.5 minutes, and overall therapy can be conducted in about 25 minutes. Our system has proven very useful for routine clinical work.