Lecture Notes on Nuclear Medicine and MIBG Therapy

Introduction

• Presenter recently relocated from Seattle, from Fred Hutch Cancer Center.
• Discussion on unique resources for NET patients at the current institution.
• Emphasis on the uniqueness and value of the program in a major cancer center.

Nuclear Medicine Basics

• Interface between medicine, chemistry, and nuclear physics.
• Importance of understanding terms and equipment in nuclear medicine.

Focus Areas

• Concentration on MIBG (meta-iodobenzylguanidine) therapy for pheochromocytomas and paragangliomas.
  • MIBG is similar to norepinephrine, used in both diagnosis and therapy.
• Importance of radioisotope imaging and therapy for early diagnosis and treatment of masses.

Radioisotopes and Nuclear Physics

• Discussion of isotopes: elements with different atomic weights (e.g., fluorine-18 vs. fluorine-19).
• Types of radioactive decay: beta decay, gamma decay, positron decay.
  • Beta particles are fast electrons; important in therapy.
  • Gamma rays are used for imaging.
  • Positron decay used in PET scans.

MIBG Therapy

• MIBG acts like norepinephrine, taken up by nerve terminals.
• Two uptake types: Type 1 (localized, high affinity) and Type 2 (less concentrated).
• Indications for use include pheochromocytomas, paragangliomas, and neuroblastomas.
• Importance of specific medication protocols to ensure accurate MIBG scans.

Imaging and Treatment

• Combination of nuclear medicine cameras with CT cameras for anatomical and functional imaging.
• MIBG therapy involves targeted radiation, effective in stopping tumor growth.

Treatment Principles

• I-131 is used due to its therapeutic benefits.
  • Highly localized radiation delivery.
• Toxicity primarily in blood and bone marrow.
• Dosage measured in millicuries; effectiveness depends on radiation absorbed by the tumor.

Future Directions

• Positron emission tomography (PET) with I-124 for better accuracy in radiation delivery.
• Exploration of astatine-211 for alpha emitter therapy.
  • Alpha emitters cause significant tissue damage in targeted areas.
  • Potentially more effective than current treatments, especially for challenging tumors.

Conclusion

• Acknowledgment of institutional leadership in developing these therapies.
• Importance of understanding nuclear physics principles applied in medical therapy.
• Open to questions and further discussions during breaks.