Attenuation of Radiation: Concepts and Mathematics

This tutorial provides 2 CEUs and is ideal for:

  1. Nuclear Medicine and Radiology Technologists. The VOICE program of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) has reviewed this program and approved it for a maximum of 81 continuing education hours. Because these tutorials have been approved by the VOICE Program, they are accepted for CE credit in all 50 states and by ARRT and NMTCB, even if you are not a VOICE/SNMMI member.
  2. Physicians requiring CME Credits to maintain IAC Accreditation. All or a portion of this educational activity may meet the CME requirement for IAC Nuclear/PET Accreditation. Our website is listed on the resources page of the IAC website.

Proceed to the Tutorial: Attenuation of Radiation Tutorial

Proceed to the Quiz: Attenuation of Radiation Quiz

Purchase Tutorial: Payment link (Credit Cards/Paypal)



This tutorial gives an overview on Attenuation of Radiation

Objectives for Tutorial on Attenuation of Radiation

Topics to be Covered

  1. Definition of terms such as attenuation, half value layer, and 10th value layer
  2. Graphic representation of the attenuation of radiation as it traverses through matter
  3. Explanation of why parallel lines on a attenuation curve have the same half value layer
  4. Comparison of mono chromatic and polychromatic beams and the associated mathematics.
  5. Questions and mathematical problem solving related to attenuation of radiation
  6. After completion of this tutorial, one should be able to:
    1. Define attenuation of radiation, half-value layer, and tenth value layer.
    2. Explain what happens to intensity of a beam as one removes or adds HVLs or TVLs between source and detector
    3. Using graphical analysis, determine HVL or TVL from a semi-logarithmic plot of Intensity vs thickness.
    4. State mathematical relationship between m (the linear absorption coefficient) and the HVL and compare to the mathematical relationship between l (the decay constant) and the half-life
    5. Write the equations for calculations involving intensity changes as a function of the number of HVLs and TVLs
    6. Define monochromatic and polychromatic and explain why every HVL is equally thick for monochromatic beams, but not for polychromatic beams.
    7. Work a variety of math problems involving change of beam intensity with change of number of HVLs or TVLs.

If you have taken one of the tutorials, received a score of 80% or above, and wish to receive CE credit: Make sure you submit all of the requested information when taking the test. It’s not necessary to send us the score sheets since we receive them electronically when you submit your answers for scoring.

Within 24 hours of receipt of your submitted score sheets and payment for the tutorial(s), we will do all of the following:

1. Send a certificate to you via e-mail
2. Send a certificate to you via US Mail
3. All members of the SNMMI will have to self-report their CE Credits on the SNMMI Website ( We will automatically send detailed self-reporting instructions to you along with your CE Credit Certificate.
If you have any problems with the self-reporting system, please contact the VOICE Coordinator directly at 703 708-9000. ).

If paying by check, please make payable to Consultants in Nuclear Medicine and mail your payment to:   Consultants in Nuclear Medicine 2910 W. Estes Avenue  Chicago, IL 60645-2394

To make sure your check is in the appropriate amount, please note the following:
If a tutorial awards 1 CEU, the cost is $20.00
If a tutorial awards 2 CEU, the cost is $30.00
If a tutorial awards 3 CEU, the cost is $40.00

If paying by credit card: we offer a secure internet service via PayPal, a well known internet provider ( for all of our Online Tutorial Courses.

Simply click the appropriate link for the tutorial for which you wish to receive CE credit.   Check your “shopping cart” order carefully- adding or deleting items before you proceed to check out.   “PayPal” credit card payments are available for anyone although you will need to submit more information if you are a new user without an established “PayPal” account.   Please use the PayPal links on the website to submit your payment.   If your credit card information does not match your score page information, please include a copy of your PayPal payment statement so we can match transactions correctly.

All of our tutorials are available for your use in reviewing for your Board Certification Examination.   There is no charge to use these tutorials unless you wish to obtain CE Credit.

Please feel free to review the tutorials as often as you wish; the test may be taken once.  If a score <80% is obtained, then the test may be retaken once.
If the score is still <80%, please contact Dr. Karesh, Tutorials Coordinator, by e-mail at for further instructions.