Chapter 31, Problem 42P

(a)

To determine

To find:The absorbed dose

Answer to Problem 42P

Explanation of Solution

Given data:

Patient received dose, 1.0 rem

Since the RBE is 1, the effective dose (in rem) is the same as the absorbed dose (in rad).

Thus the absorbed dose is 1.0 rad or $0.010\text{Gy}$

Conclusion:

The absorbed dose is 1.0 rad or $0.010\text{Gy}$

(b)

To determine

To find:The number of proton absorbed by the tumor

Answer to Problem 42P

  $1.3\times {10}^{10}\text{p}$

Explanation of Solution

Given data:

Energy of proton is $1.2\times {10}^6\text{eV}$

Mass of tumor is 0.25 kg

The absorbed dose is 1.0 rad or $0.010\text{Gy}$

  $\text{1 Gy =1 J/ kg}$

The number of proton absorbed by the tumor is

  $\begin{array}{l}(0.01\text{Gy})\left(\frac{1\text{J}/\text{kg}}{1\text{Gy}}\right)(0.25\text{kg})\left(\frac{1\text{eV}}{1.60\times {10}^{-19}\text{J}}\right)\left(\frac{1\text{p}}{1.2\times {10}^6\text{eV}}\right)=1.3\times {10}^{10}\text{p }\hfill \end{array}$

Conclusion:

The number of proton absorbed by the tumor is $1.3\times {10}^{10}\text{p}$