HL Chemistry D.8: Nuclear Chemistry

Brachytherapy

• Permanent or temporary insertion of a radioactive isotope into the body

• Treats head, neck, womb, prostate or cervical cancer

• gamma emitters

• palladium-131, cobalt-60

Radioisotope Therapy

• Orally/injected radioisotopes

• Iodine-131 (beta-emitter) given orally to treat thyroid cancer

types of radiotherapy

• Brackytherapy

• Radioisotope therapy

• Proton beam therapy

• Neutron beam therapy

Alpha particles

• Helium-4

• Highly damaging

• Does not penetrate well (travel length of a cell)

Beta particles

• Electron released from the split of a neutron into electron and proton

• Damaging

• Travels more than alpha

Reasons why Technetium-99m (Tc) is used in diagnostics

• almost pure gamma emitter

  • function like x-rays, penetrate body, not too harmful

  • track via gamma camera

• half-life: 6h

  • Patient doesn’t stay radioactive for too long

• Radioactive tracer

• m in Tc-99m is metastable → allows for excess energy to be emitted as gamma rays

• Forms water soluble compounds (TcO4-) that can be excreted through urine

Use of yttrium-90

• beta particle emitter

• treat liver cancer

• 30 µm beads injected into bloodstream

• half-life: 6.71 days

• specific cells in small area destroyed

Use of lutetium-177

• beta and gamma emitter

• neuroendocrine cancer

• can also be used to image b/c of gamma rays

TAT

• Targeted alpha particle therapy

• alpha emitting radioisotopes carried by monoclonal antibodies to cancer cells

• Radioisotopes considered: astatine-211 (half-life = 7.2h), lead-212 (half-life = 10.6h)

• Radioactive radium chloride

  • radium-223, half-life = 11.4 days, alpha and gamma emitter