Researchers at the Georgia Institute of Technology have developed a computerised system that would help radiation oncologists optimise placement of radioactive ‘seeds’ for non-surgical prostate brachytherapy.
Beyond providing treatment more precisely tailored to each patient, the system targets escalated doses of radiation at tumour pockets and is said to account for changes that occur in the volume of the prostate during treatment.
The automated system is said to offer a dramatic reduction in the time required to design radioactive seed treatment, allowing optimised plans to be created in minutes, and revised as the procedure proceeds.
To successfully treat the cancer with prostate brachytherapy physicians must carefully design the radiation dose, balancing the high radiation levels needed to eradicate the cancer against the need to protect nearby tissue.
Further complicating treatment is the edema that occurs as needles are inserted to place the seeds. Resulting changes in prostate volume can mean delivering too little radiation at the beginning of treatment and too much as the swelling subsides.
‘Proper coverage of the entire prostate is very important, but it can be very difficult to carry out the plan,’ said Eva K. Lee, assistant professor of industrial and systems engineering at the Georgia Institute of Technology and of radiation oncology at Emory University School of Medicine. ‘The seeds cannot always be placed in the location you want, so you must be able to compensate for that. Our system allows real-time planning, and corrections can be made as you proceed.’
Ultrasound images of the patient’s prostate are used by the system to help determine optimal radioactive seed placement. Mixed integer programming and computational optimisation techniques are the core technological tools utilised.
‘To the physician, this will be a black box,’ Lee said. ‘They will not need to know what is going on with the mathematics. All they will have to do is tell the system what they want in the plan.’
Less experienced oncologists working in remote areas could use the system to aid in producing high quality treatment plans.
In most current treatments, seed placement is determined manually based on a simulation of the patient’s prostate. Done days or weeks ahead of the operation, this ‘pre-plan’ is said to takes hours to produce. By cutting the planning time to as little as 15 minutes, the system should reduce costs and allow physicians to spend more time with their patients, Lee added.
Though the expert system is ready for commercialisation, it will have to receive US FDA approval before being made available to treatment centres.
However, Lee has used real patient data to compare her system against treatment plans designed by radiation oncologists. Those results suggest the system will provide significant improvements in the outcome of treatment.
‘We can deliver better precision and create the optimal plan for each patient. This system should help cut the recurrence rate for prostate cancer and reduce toxicity to healthy tissue,’ concluded Lee.