Total dose for prophylactic cranial irradiation is typically:

For prophylactic cranial irradiation (PCI), the typical total dose administered is around 3600 cGy. This dosage is commonly used to reduce the risk of metastases to the brain, particularly for patients with certain types of cancers such as small cell lung cancer.

The dosing regimen for PCI often involves daily fractions, usually delivered over a span of 10 to 15 treatments, which allows for effective treatment while managing the risk of side effects. The 3600 cGy dose strikes a balance between being therapeutic enough to provide the desired prophylactic benefit while minimizing the potential for adverse reactions to the central nervous system.

Other doses mentioned may not align with standard practices for PCI. For example, doses like 2000 cGy are generally considered too low to achieve adequate prophylaxis, while higher doses, such as those approaching 4500 cGy, could increase the risk of toxicity without significant additional benefit in this preventive setting. Thus, 3600 cGy remains the accepted standard for this type of treatment, underlining its effectiveness in preventing brain metastasis in high-risk patients.