Is rectangular collimation required?

I had two doctors, Dr. Klampe and Dr. Lesch, ask me this question today. Both were concerned about costly changes to their X-ray systems that might be required by law. This question stemmed from their reading of Sullivan-Schein’s “Sidekick” Autumn 2005 edition. Below are some of the quotes from the article that caught their eye.

“Note: According to the NCRP Report, Collimating your X-ray beam is required both for digital and film based X-rays.”

“Collimation the X-ray beam to the precise size of the image receptor eliminates scatter radiation.”

“The new report (NCRP #145) mandates the use of a rectangular collimator.”

“The use of leaded aprons on patients shall not be required if all other recommendations in this Report are rigorously followed.”

Ok, after researching everything, here is my take on things.

First off, NCRP stands for National Council on Radiation Protection and Measures. They can be found here: The NCRP is not a governing body; it is a private corporation. This means that they cannot require you via mandate to do anything. Basically the council attempts to establish universally accepted norms. The council has four objectives in its charter

  1. Collect, analyze, develope and disseminate in the public interest information and recommendations about protection and measurement of radiation.
  2. Provide means for cooperation of organizations concerned with measurements and protections associated with radiation.
  3. Develop basic concepts about radiation quantities, units, and measurements.
  4. Cooperate with the Internation commission on Radiological Protection, The Federal Radiation Council, the International Commission on Radiation Units and Measurements, and other organizations concerned with radiation quantites, units, and measurements and with radiation protection.

Secondly, I spoke with Marge Shaw at the Minnesota Department of Health on the issue of collimation and lead vests. At present there is NO state or federal requirement for rectangular collimation. The use of lead vests in the state of Minnesota is also NOT required. She did not think that we would see anything regarding this issue even in the next year.

Thirdly, I asked myself, what are the pros/cons of this?

  • Is collimation required? — Yes. All X-ray units are required to have collimation.
  • Is rectangular collimation of intra-oral X-ray units required by law — No. Not at present.
  • Is there a substantive reduction in scatter radiation by going to rectangular collimation in place of round? — Yes! Almost a 68% reduction.
  • Will this result in more chance for cone cut and consequent retakes? — Yes.
  • Are retakes counter-productive to the goal of radiation reduction? — You bet they are! Not to mention the frustration of cone cut images and time delays associated with the retakes.
  • Can the cone cut be minimized using positioning devices? — Yes.
  • Will my doctors be required to replace their X-ray machines to realize this reduction in scatter radiation through the use of rectangular collimation? — No. We have Rectangular Position Indicating Devices (PIDs) to replace all intra-oral X-ray units and Film Positioning Instruments (FPIs) both of which are pictured below. Most of these devices and adaptations can be done for under $300 per X-ray unit. If you have interest in this conversion, please call.

Rectangle PIDfpi