1. May 1, 2010

### Millano

1. The problem statement, all variables and given/known data

Calculate minimum thickness of concrete wall of radiation room (2X2X2) such that radiographer doesnt exceed dose limit. Use info below.

X ray reading surface of patient (50 cm from source) = exposure= 4.29 X 10$$^{}-4$$

effective energy of x ray beam = 40 kev

40% of x rays are transmitted

does limit =7.5 mGy per anum

linear attenuation coeficent = 1.16 cm

scattered radiation increases does by 5%

wair/e = 33.97
$$\mu$$/$$\rho$$=6.83x 10$$^{}-5$$

50 x rays taken per day

2. Relevant equations

intensity =1/d^2

I (X) = I0e µx

exposure X = dq/dm = $$\psi$$.($$\mu$$/$$\rho$$).e/wair

3. The attempt at a solution

well, You have to find the intensity(no of photons)/radiation of the x ray beams after passing through the patient. Using this you can calculate the thickness needed using the linear attenutation coefficent.

What I dont get is how the expousre and effective energy relate to the intensity of the beam after passing through the patient and how this changes as the distance increases

Last edited: May 1, 2010
2. May 13, 2010

no one ?