Bio
Damion Gilpin was born in parish of Hanover and raised in Sandy Bay. He attended Rusea’s Comprehensive High School before going on to the University of Technology, Jamaica, where he earned a Bachelor of Engineering Degree in Mechanical Engineering. He has made an indelible mark in the shaping of young minds at Manning’s and Mona high schools where he worked as a teacher consequent to his love for applying the principles of Mathematics and Physics.
He holds a Master of Science Degree in Medical Physics from the University of the West Indies and received an International Atomic Energy Agency (IAEA) fellowship at the University of Trieste and the International Center for Theoretical Physics. Additionally, he completed a medical physics internship at the Istituto Oncologico Veneto in Padova, Italy.
Mr. Gilpin is a certified Therapeutic Medical Physicist recognized by the International Organization for Medical Physicists (IOMP). Since 2018, he has worked as a Senior Medical Physicist at the National Cancer Treatment Center at St. Joseph Hospital and previously served as an adjunct lecturer in the Master of Science programme for Medical Physics at the University of the West Indies, Mona.
Abstract
Verification of Ethos CBCT-guided online adaptive radiotherapy for prostate cancer using Raystation hybrid DIR algorithm, ANACONDA
Prospective/Objective: Radiotherapy plays a crucial role in managing localized prostate cancer, where the planning process involves utilizing a snapshot dataset of the patient’s anatomy during simulation. However, anatomical changes can occur between and within fractions, necessitating adaptation strategies. This study aims to comprehensively analyze the dynamics of dose accumulation during the treatment localized of prostate cancer, utilizing both scheduled plans (SPs) (reference treatment plan recalculated on the daily anatomy) and adapted plans (APs) (reference treatment plan reoptimized to match the clinical directive) within the Ethos system, employing the Raystation ANACONDA DIR algorithm.
Materials and methods: Eight patients treated with Ethos oART (60Gy/20 fractions) were retrospectively selected. The initial reference treatment plan was generated based on the planning CT (pCT) using Ethos. Before treatment, cone beam CT (CBCT) images were obtained, and the pCT data was mapped onto the CBCT image, thus creating the synthetic CT (sCT). An artificial intelligence algorithm then identified the influencer organs (prostate, bladder, rectum, and seminal vesicle). Ethos’ deformation algorithm utilized these influencer organs to guide the deformation of the CTV and PTV from the pCT to the CBCT image. SPs and APs were subsequently generated on the sCT.
Daily CBCT images, SPs, APs, and reference treatment plans were transferred to Raystation TPS. Rigid image registrations (RIRs) were executed between pCTs and sCTs, followed by the deformable image registrations (DIRs) using the influencer organs as controlling regions of interest (ROIs) for each fraction. The dose corresponding to the DIR was then deformed to the pCT, and a dose accumulation analysis was conducted for both scheduled and adapted plans across all patients. Evaluation metrics included the Dice similarity coefficient (DSC), mean distance to agreement (MDA), and the Jacobian determinant (JD).
Results: Results indicated favorable DIR metrics, with influencer organs mean DSC ranging from 0.89 to 0.98, and the MDA from 0.03 cm to 0.09 cm. JD values for prostate, bladder, rectum, and seminal vesicle ranged from 0.77 to 1.11. notably, AP demonstrated improved PTV coverage compared to SP. For D98% > 95%, 25% of the patients achieved an adapted mean of 94.65%, compared to 12.5% achieving a mean of 88.05% for the SP. For D95% > 95%, AP displayed enhanced PTV coverage, with 100% of the cohort attaining a mean of 97.16%, whereas 25% achieved 92.25% for SP. CTV coverage remained high in both plans, with mean values of 98.03% and 99.13% for SP and AP, respectively.
Although OARs met clinical goals in both plans, AP exhibited increase volumetric dose to OARs. Patient-specific results unveiled target coverage coincidence in four cases, while the remaining four showed a deviation of PTV coverage between Raystation and Ethos delivered dose accumulations, signifying the impact of anatomical changes during adaptation.
Conclusion: Ethos oART emerges as an appealing modality for intact prostate cancer treatment, offering satisfactory CTV and PTV coverage while safeguarding OARs. Potential improvements in PTV coverage could be achieved with enhanced patient preparation and increased clinical staff efficiency