Las Vegas, Nevada ( Phillip Kuo, MD, PhD, gave an overview discussing important radiation safety considerations and logistical considerations for starting 177-Lutetium-PSMA targeted therapies.

The physical half-life Lutetium-177 is 6.65 days. The beta-particles have an Emax of 497 keV (78.6%), 384 keV (9.1%), 176 keV (12.2%), the gamma photons with Ey of 208 kEv (11%) and with 113 keV (6.6%).

Lutetium-177 properties include:

  • Favorable chemistry for chelation
  • Mean penetration range of beta particles is 670 um in soft tissues
  • The half-life of almost one week (helpful for synthesis and transport)
  • Gamma photons allow for imaging

It is imperative to get the radioactive materials license for use of this radiopharmaceutical. However, if it is needed for off-label use it is required to get an internal review board (IRB) approval. It is also important to consider radioactive waste management. Radioactive waste includes:

  • The vial that dose came in
  • Needle to draw up the dose from the vial
  • 3 syringes – dose syringe and 2 flush syringes
  • IV and tubing equipment
  • There is even more waste the infusion method is used (longer tubing, bigger syringe)
  • Gloves and gauze

Additional considerations require the whole body and finger ring dosimeters.

Although there is still no consensus, patient safety instructions for this treatment include the following:

  • Use of the principle of ALARA (As low as reasonably achievable) for radiation
  • It is important to hydrate and void bladder frequently for 2-3 days
  • The beta particle is short-range, most bremsstrahlung effect will be absorbed (bremsstrahlung =electromagnetic radiation produced by the acceleration or especially the deceleration of a charged particle after passing through the electric and magnetic fields of a nucleus)
  • Advise against prolonged proximity to pregnant women and children
  • Bathroom specific instructions
  • Laundry instructions
  • Sleeping in a separate bed
  • Verification of treatment card for travel

If Lutetium 177 PSMA-targeted radiopharmaceutical is approved by FDA, presumably there will be more specific guidelines on:

  • When to perform a complete blood count with differential for bone marrow reserve
  • What imaging requirements will be needed:
    1. PSMA-targeted imaging
    2. FDG-PET?
    3. Bone scan
  • CT/MRI depending on what areas of metastatic disease allowed (liver, lung, brain, etc.)
  • Other blood work such as liver function tests and creatinine
  • History of therapies

The main adverse effects of this treatment include 12% grade 3-4 hematologic adverse effects, 13% fatigue, 8% xerostomia, 12% renal failure (but 0% grade 3-4).

The last topic discussed by Dr. Kuo was the importance of collaboration with the department of medical oncology. This is most important, and it is possible to build on the previous collaboration from the Radium 223 treatment program. Multiple discussions are required between these different medical fields regarding the initiation of therapy, dose reduction, blood tests, and symptoms so that a complete treatment plan can be created, recommended by all specialties involved. This is the most important principle for treatment success.

Presented by: Phillip Kuo, MD, PhD, Professor, Medical Imaging, Biomedical Engineering and Medicine, Division Chief, Nuclear Medicine, and Director of PET/CT, Director of the Nuclear Medicine Fellowship Program, College of Medicine Tuscon, Medical Imaging, The University of Arizona Health Sciences.

Written by: Hanan Goldberg, MD, Urology Department, SUNY Upstate Medical University, Syracuse, New-York, USA @GoldbergHanan at the 2019 SNMMI Therapeutics Conference: Therapies, Theranostics, and Building Your Radionuclide Clinical Practice, October 25-27, 2019 in Las Vegas, Nevada.