Presented by Yohan Walter, MS, DABR
Willis Knighton Cancer Center

Fueled by radiotheranostics, the field of nuclear medicine has experienced a sudden and recent boom. Radioligand therapy, a form of theranostic treatment, delivers radiation targeted at the molecular level, allowing patients to benefit from the potency of radiotherapy in scenarios where external beam radiation therapy (EBRT) on its own would offer little upside.

Increasing numbers of facilities in the United States have started, or will soon open, theranostics programs. Many of these programs will be run through existing radiation oncology departments, requiring rapid cross-training and staff education. However, this evolving landscape also offers opportunities for existing staff to diversify their skills and build a unique niche within this changing environment.

Post-infusion dosimetry remains one of the most important, yet poorly understood aspects of current theranostics practice. Standardization, accuracy, and reproducibility in dosimetry procedures are needed to fully realize the potential of theranostics. Beyond radioligand therapy alone, multiple active clinical trials are exploring the synergy between theranostics and EBRT by combining therapies in one comprehensive care plan. The safe combination of these modalities requires careful consideration of the respective radiation doses from each source in treatment planning and assessment.

Having completed extensive training in dose calculation and treatment planning methods in radiation therapy, medical dosimetrists may be uniquely well-suited to support new and growing theranostics programs. In this presentation, we provide a conceptual overview of the theoretical basis for theranostics, summarize the current clinical evidence, and review real-world cases which demonstrate the immense potential, current challenges, and multimodal synergies in radioligand therapy.

Learner Outcomes:

1. Explain the theoretical basis and clinical evidence behind radiotheranostics
2. Discuss the current status, challenges, and future directions in theranostics
3. Explore the synergies between theranostics and other modalities, including external beam radiation therapy

Educational Level: Intermediate

Presenter: Yohan Walter, MS, DABR is a radiation oncology and nuclear medicine physicist at the Willis Knighton Cancer Center (WKCC, Shreveport, LA). He provides physics coverage in the Department of Radiation Oncology, Proton Therapy Center, and Nuclear Oncology Division. He is the Physics Lead for WKCC’s stereotactic radiosurgery program and Nuclear Oncology Division. He played a major role in the establishment of the theranostics program, leading aspects in protocol development and clinical practice.  

Outside of clinical duties, Yohan is the Chief of Radiation Physics Research at WKCC. His research interests mirror his clinical responsibilities, spanning most aspects of radiation medicine, including SRS/SBRT, proton therapy, RT for benign disease, and theranostics. He leads an interdisciplinary research group comprised of WKCC staff, medical students from LSU Health Shreveport School of Medicine, and Louisiana Tech University undergraduates.

Yohan is active in various educational initiatives, including designing the curriculum for the first-of-kind Willis Knighton Nuclear Oncology Physics Fellowship. Additionally, he mentors SRS/SBRT, IGRT, and RPT rotations in the WKCC medical physics residency program. He contributes to multiple association-led initiatives, including the ASRT Advanced Practice Radiation Therapy Curriculum Working Group.

Yohan earned his BS from the University of Oregon in 2019 (go Ducks!), MS from Creighton University in 2022 (go Jays!), and completed his therapeutic physics residency at WKCC in 2024 (go…uh…hmm…). He is a student in the clinical research PhD program at the University of Jamestown (go Jimmies!). Outside of work, he enjoys tending to his Carolina Reaper plants and playing with his puppy.

ARRT CQR Credit Distribution
Nuclear Medicine Technology 2022       
   Procedures    
   Endocrine and Oncology Procedures = 1.0
Nuclear Medicine Technology 2027       
   Procedures    
   Endocrine and Oncology = 1.0