Medical Application Of Algerbra

Question 1

What is the algebraic formula used to calculate dose in radiotherapy?

Answer 1

D= R x T
D= dose
R= dose rate (Gy/min)
T= time of exposure (minutes)

Question 2

If the prescribed dose (D) is known, how can you solve for time?

Answer 2

Rearrange formula - D=R x T
T= D/ R

Question 3

How can algebra help calculate beam attenuation in tissue using the exponential decay formula?

Answer 3

I = I 0 X e ^ −μ x
I= intensity after attention
I0 = initial intensity
μ=linear attenuation coefficient
X= depth

Question 4

What does the variable μ represent in beam attenuation equations?

Answer 4

The linear attenuation coefficient, representing how much the beam is absorbed per unit thickness

Question 5

A patient’s tumour requires a dose of 20 gy. The dose rate is 2 gy/min. How long must the treatment last ?

Answer 5

D = r x t
T=d/r
T= 20 / 2
T= 10 minutes

Question 6

How does algebra help determine the monitor units in a linear accelerator?

Answer 6

MU= Dose/ C×O×TPR
where C= calibration factor, O = output factor,
TPR = tissue phantom ratio.

Question 7

If Io = 100 and μ =5cm ^-1 what is the beam intensity at 10 cm depth?

Answer 7

I=100 x e^ -0.05 x 10 = 100 x e^ -0.5 =0.607 60.6

Question 8

Why is algebra essential in fractionation schedules for radiotherapy?

Answer 8

Algebra helps distribute the total dose (d) across fractions
D total = N x D where n= number of fractions and d= dose per fraction