Presented by Jeffrey Antone, BS, CMD
Chief Medical Dosimetrist
North Shore LIJ Medical Center

Recorded 9/13/19

Increased attention to treatment plan turnover has created a very stressful atmosphere for Medical Dosimetrists. Whether it’s a patient completing chemotherapy, teeth extraction, improper setup, or late contours, treatment planners have the burden to generate a quality treatment plan. Their patient load continues to grow and the timeline is shorter. Novice to seasoned dosimetrists create dose objectives for optimizing or predetermined dose constraints based on their experience. The end goal is all the same, signing off on a quality plan in a timely manner. However, the amount of assisting optimization structures created and the range of priorities used during optimization can lead wasted time and potential errors. Planners can end up staying past their work hours, cycling through iterations, risking fatigue and burn-out. Generalized Equivalent Uniform Dose (gEud) has been an effective tool to assist treatment planning as an alternative to making assisting optimization structures and multiple dose volume parameters. Yet the range of numbers is still large and planners might not know where to start. AAPM TG-166 presented starting values for serial and parallel structures. We will attempt to use those numbers as a starting point and find the right balance of “a-values”, where “a” is the biological parameter used in calculating the gEUD, and the priorities for both the Planning Target Volumes (PTV) and Organs at Risk (OAR) to provide the optimal plan completed in an efficient manner.

We have taken clinically accepted specialized head and neck plans and the challenges treatment planners face when generating a plan. We compared Dosimetrists’ optimization styles to help find that ratio of IMRT optimization priorities and “a” values that can be universally accepted to get the optimal tumor coverage while maximizing the dose constraints at the organs at risk. We are examining the numbers that have been working well at our institution. Our goal in this study is to provide a standard template in IMRT optimization for Head and neck plans to assist in efficient treatment planning.