Periodic Table/Medicine/Radiopharmaceuticals

Radiopharmaceuticals

Radioactive isotopes used in medical imaging, radiation therapy, and brachytherapy.

α alphaβ⁻ beta-minusβ⁺ beta-plusγ gammaEC electron capture

Diagnostic Imaging

Technetium (Z=43)

t_1/2 = 6.01 h98.9062 u

Most widely used diagnostic isotope. Bone scans, myocardial perfusion imaging, renal function studies. Emits 140 keV gamma rays ideal for gamma camera detection.

F-18 (FDG)

Fluorine (Z=9)

β⁺

t_1/2 = 109.8 min18.0009 u

PET scanning with fluorodeoxyglucose (FDG). Cancer detection and staging, brain imaging for Alzheimer's, cardiac viability assessment.

I-123

Iodine (Z=53)

t_1/2 = 13.2 h122.9056 u

Thyroid imaging and uptake studies. Preferred over I-131 for diagnostic imaging due to lower radiation dose and better image quality.

Ga-67

Gallium (Z=31)

t_1/2 = 3.26 d66.9282 u

Infection and inflammation imaging. Tumor imaging for lymphoma and hepatocellular carcinoma. Accumulates in areas of rapid cell division.

Tl-201

Thallium (Z=81)

t_1/2 = 3.04 d200.9708 u

Cardiac stress testing and myocardial perfusion imaging. Taken up by viable myocardium proportional to blood flow.

Therapeutic (Radiation Therapy)

I-131

Iodine (Z=53)

β⁻

t_1/2 = 8.02 d130.9061 u

Thyroid cancer ablation and treatment of hyperthyroidism. Selectively concentrated by thyroid tissue via the sodium-iodide symporter.

Co-60

Cobalt (Z=27)

t_1/2 = 5.27 y59.9338 u

External beam radiation therapy. Gamma Knife stereotactic radiosurgery for brain tumors. Produces two gamma rays at 1.17 and 1.33 MeV.

Ra-223

Radium (Z=88)

t_1/2 = 11.4 d223.0185 u

Treatment of bone metastases from castration-resistant prostate cancer (Xofigo). Alpha particles provide high linear energy transfer with short range.

Lu-177

Lutetium (Z=71)

β⁻

t_1/2 = 6.65 d176.9438 u

Peptide receptor radionuclide therapy for neuroendocrine tumors (Lutathera). Prostate cancer therapy (PSMA-targeted). Dual beta/gamma emission allows therapy and imaging.

Sr-89

Strontium (Z=38)

β⁻

t_1/2 = 50.5 d88.9075 u

Bone pain palliation for metastatic cancer. Mimics calcium and is incorporated into bone at sites of active osteogenesis.

Brachytherapy

Ir-192

Iridium (Z=77)

t_1/2 = 73.8 d191.9626 u

High-dose-rate brachytherapy for cervical, head and neck, breast, and lung cancers. Versatile energy spectrum suitable for many treatment sites.

Cs-137

Cesium (Z=55)

γ/β⁻

t_1/2 = 30.2 y136.9071 u

Low-dose-rate brachytherapy for cervical cancer. Blood product irradiation to prevent transfusion-associated graft-versus-host disease.

Pd-103

Palladium (Z=46)

t_1/2 = 17.0 d102.9061 u

Permanent prostate cancer seed implants. Low-energy photon emission provides rapid dose delivery with short effective treatment time.