1. Chapter 9 Nuclear Radiation
9.3
Radiation Measurement

2. Geiger Counter A Geiger counter detects beta and gamma radiation
uses ions produced by radiation to create an electrical current

3. Units for Measuring Radiation
Units for measuring radiation activity include
Curie – measures activity as the number of atoms that decay in 1 second
rad (radiation absorbed dose) – measures the radiation absorbed by the tissues of the body
rem (radiation equivalent) – measures the biological damage caused by different types of radiation

4. Measuring Radiation Activity
Often the measurement for an equivalent dose is in millirems (mrem). One rem is equal to 1000 mrem. The SI unit is the sievert (Sv). One sievert is equal to 100 rem.

5. Radiation Exposure Exposure to radiation occurs from
naturally occurring radioisotopes
medical and dental procedures
air travel, radon, and smoking cigarettes
cosmic rays

6. Radiation Sickness
LD50
is the amount of radiation to the whole body that is the lethal dose for one-half the population
varies for different life-forms, as Table 9.6 shows

7. Learning Check
A typical intravenous dose of I-125 for a thyroid diagnostic test is 100 Ci. What is this dosage in megabecquerels (MBq) (3.7  1010 Bq = 1 Ci)?
A MBq
B  106 MBq
C  102 MBq

8. Solution
A typical intravenous dose of I-125 for a thyroid diagnostic test is 100 Ci. What is this dosage in megabecquerels (MBq) (3.7  1010 Bq = 1 Ci)?
100 Ci  Ci  3.7  1010 Bq  1 MBq x
1 x 106 Ci Ci  106 Bq
= 3.7 MBq The answer is A.