Question

In proton beam therapy, a beam of high-energy protons is used to deliver radiation to a tumor, killing its cancerous cells. In one session, the radiologist calls for a dose of 4.9×108 protons to be delivered at a beam current of 120 nA.

How long should the beam be turned on to deliver this dose?

Answer 1

In proton beam therapy, the time required to deliver a dose can be calculated using the formula Time (s) = Dose (protons) / Beam Current (protons/s). Plugging in the given values, the beam should be turned on for approximately 4.1 x 10^15 seconds to deliver the desired dose.

Step-by-step explanation:

In proton beam therapy, the dose delivered is usually measured in units of Gray (Gy), which represents the amount of radiation energy absorbed by the tissue. The beam current represents the number of protons passing through a given point per unit of time. To calculate the time required to deliver the dose, you can use the formula:

Time (s) = Dose (protons) / Beam Current (protons/s)

Plugging in the given values, we get:

Time = 4.9 x 10^8 protons / 120 x 10^-9 A

Simplifying the units and performing the calculation, we find that the beam should be turned on for approximately 4.1 x 10^15 seconds to deliver the desired dose.