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SNMMI 2019: Vest to Personalize Lu-177 Dotatate Therapy for Neuroendocrine Tumors

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Key Points

  • Preliminary vest results from simulations are showing that at-home vest measurements made over 7 to 21 days can provide organ-specific washout rates with precision as good or better than the current accepted gold standard of three to four quantitative SPECT/CT images acquired over 7 days.
  • The garment (called a multidetector personalized home dosimetry [MD PHD] vest) will house 15 to 20 small radiation detectors, strategically placed within the vest based upon the patient’s own anatomy. In addition to the radiation detectors, the vest will be coupled to a compact electronics pack that will acquire the data and send it via WiFi or cellular services to a secure website where medical personnel/software can check the data for quality control in near real-time.

Researchers at the University of Washington are developing a user-friendly vest with technology that collects data to tailor personalized therapy for patients with metastatic, somatostatin receptor 2–positive neuroendocrine tumors (NETs). Their study was presented at the 2019 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) and published by Miyaoka et al in The Journal of Nuclear Medicine.

Background

Targeted therapy using lutetium Lu-177 dotatate greatly increases progression-free survival for patients with NETs. While approved by the U.S. Food and Drug Administration (FDA), the FDA package instructions call for patients to receive a standardized protocol of the therapy—regardless of size or weight. Traditionally, targeted radionuclide therapies are personalized based on dose to the main organs at risk (eg, kidneys, liver, spleen).

“Organ-specific dosimetry for Lu-177 dotatate is the norm at many medical centers outside of the United States,” explained Robert Miyaoka, PhD, of the University of Washington. “Longitudinal imaging studies are conducted after each therapy treatment to determine the cumulative dose to the organs at risk for each patient. The standardized Lu-177 dotatate treatment protocol in the United States consists of four 200 mCi doses spaced 2 months apart. Although this is safe for a vast majority of patients, it is less than optimal for most. Studies out of Europe are revealing that tailoring the number of treatment doses based upon the dose-limiting toxicity to the patient’s organs at risk can more than double the progression-free and overall survival for patients [with NETs] undergoing Lu-177 dotatate therapy.”

Another factor the researchers sought to address is the fact that traditional imaging-based methods for organ dosimetry estimation for Lu-177 dotatate require three to four longitudinal imaging sessions spread over 7 days.

Preliminary Technology Results

“We propose to create a lightweight, low-cost, wearable, patient-specific technology that will allow organ-specific measurement recordings to be made within the comfort of the patient’s home,” said Dr. Miyaoka. “The garment (called a multidetector personalized home dosimetry [MD PHD] vest) will house 15 to 20 small radiation detectors, strategically placed within the vest based upon the patient’s own anatomy. In addition to the radiation detectors, the vest will be coupled to a compact electronics pack that will acquire the data and send it via WiFi or cellular services to a secure website where medical personnel/software can check the data for quality control in near real-time.”

He further explained, “The patient will be asked to wear the vest for a 2-minute data acquisition once a day for 7 (and up to 21) days. Based upon these at-home measurements and a single single-photon emission computed tomography (SPECT)/CT image taken 24 hours after the therapy administration, organ specific dosimetry will be determined for all of the patient’s organs at risk.”

With the information collected via the vest, physicians would be able to tailor the number of treatments based upon personalized organ dosimetry information.

Dr. Miyaoka reported, “Preliminary vest results from simulations are showing that at-home vest measurements made over 7 to 21 days can provide organ-specific washout rates with precision as good or better than the current accepted gold standard of three to four quantitative SPECT/CT images acquired over 7 days. The initial goal of this technology is to enable personalized Lu-177 dotatate therapies in the United States, and to lower the cost for treatment personalization throughout the world.”

Disclosure: For full disclosures of the study authors, visit jnm.snmjournals.org.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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