Understanding the Effects of Metal Implants in Proton Therapy

When treating cancer with high energy particles, patients having metal implants near the tumor can create a difficult situation. When particles interact with the metal it can cause scattering within the patient. This creates difficulty because scattering makes it harder to predict the dose distribution in the planning process, thus making it difficult to accurately prescribe a treatment plan. A study was performed to better understand the effects metal implants can have on proton therapy treatments targeting tumors near the spine, and in so doing take steps toward making the treatment planning process less difficult and more accurate. The preliminary results, which show both underdosing and overdosing to the gross tumor volume and clinical target volume, will be discussed here as well as what will be done to confirm these results and resolve any discrepancies.