Dosimetry I and II and Radiobiology II

The first presentation introduces methods for performing organ-level and voxel-level radiopharmaceutical therapy (RPT) dosimetry. The reference model-based MIRD formulism as well as direct Monte Carlo based methods for highly patient specific dose estimation using the patient’s SPECT and CT images as the input are discussed. The main steps of the dosimetry calculation including serial imaging, activity quantification, image registration, segmentation, time-activity fitting, and absorbed dose estimation are introduced together with the main sources of uncertainty. How individualized dosimetry before, during and after therapy can enhance RPT are covered. Methods for simplifying the dosimetry protocol to make it practical for clinical implementation are discussed including recently available AI-based tools.

In the second presentation, basic bio-effect modeling based on the linear-quadratic model is introduced. A large focus is on the biological effective dose (BED), how it is calculated, why it should be more utilized in RPT than in external beam (EBRT), and why it is a better correlate with outcome than absorbed dose. The presentation explores the theoretical comparison of EBRT and RPT doses and the limitations of that translation, especially with regard to normal organ toxicity threshold determination in RPT. Finally, the particularities and challenges of alphaRPTs are explored, including low count rate imaging, radioactive daughters, sub-organ dosimetry, the relative biological effect (RBE), and stochastic energy deposition.  

Topics:

  • Dosimetry I – Dosimetry Methods and Individual Dose Planning, Uncertainties - Yuni Dewaraja, PhD
  • Dosimetry II / Radiobiology II – Bioeffect Modeling, Tumor Dose-Response, Toxicities, Alpha Emitters - Robert Francois Hobbs, PhD

Target Audience

This activity is designed to meet the interests of radiation oncologists, radiation physicists, radiation biologists and radiation oncology residents.

Learning Objectives

Upon completion of this activity, participants should be able to do the following:

  • Explain the main steps that need to be performed for RPT dose estimation.
  • Describe how dosimetry guided treatment can be used to enhance the efficacy of RPT while keeping toxicity at an acceptable level.
  • Determine if the imaging requirements associated with RPT dosimetry can be reduced.
  • Explain and perform BED calculations using the Medical Internal Radiation Dosimetry (MIRD) formalism or dose rate functions.
  • Convert RPT doses to EBRT values, yet understand the challenges and limitations in those conversions.
  • Discuss the challenges of alphaRPT dosimetry.
Course summary
Available credit: 
  • 2.00 AMA PRA Category 1 Credit™
    The American Society for Radiation Oncology (ASTRO) is accredited by the Accreditation Council for Continuing Medical Education for physicians. ASTRO designates this for a maximum of 2.00 AMA PRA Category 1 Credit™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.
  • 2.00 Certificate of Attendance
    This activity was designated for 2.00 AMA PRA Category 1 Credit™.
Course opens: 
03/28/2024
Course expires: 
07/04/2026
Cost:
$0.00
Rating: 
0
  • Yuni Dewaraja, PhD, is employed by University of Michigan Medicine. Dr. Dewaraja receives compensation from MIM Software and grant/research funding from GE Healthcare. 
  • Robert F. Hobbs, PhD, is employed by Johns Hopkins Medical Institute. Dr. Hobbs receives honoraria from Novartis/AAA and Varian. Dr. Hobbs receives compensation from Vivos. Dr. Hobbs owns the copyright for RAPID Dosimetry. Dr. Hobbs serves as Chair of the Radiopharmaceutical Therapy Subcommittee with AAPM.

The American Society for Radiation Oncology (ASTRO) is accredited by the Accreditation Council of Continuing Medical Education to provide continuing education to physicians.

ASTRO is awarded Deemed Status by the American Board of Radiology to provide SA-CME as part of Part II Maintenance of Certification.

Available Credit

  • 2.00 AMA PRA Category 1 Credit™
    The American Society for Radiation Oncology (ASTRO) is accredited by the Accreditation Council for Continuing Medical Education for physicians. ASTRO designates this for a maximum of 2.00 AMA PRA Category 1 Credit™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.
  • 2.00 Certificate of Attendance
    This activity was designated for 2.00 AMA PRA Category 1 Credit™.

Price

Cost:
$0.00
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