“Whoa! It’s like Spotify but for academic articles.”

Instant Access to Thousands of Journals for just $40/month

Try 2 weeks free now

A Technic for Cross-Calibration of X-Ray Units Utilizing Half-Value-Layer Determinations

A Technic for Cross-Calibration of X-Ray Units Utilizing Half-Value-Layer Determinations 1 Leon Pape , M.S. , S. Baker , R.T. and Hyman L. Gildenhorn , M.D. 1500 E. Duarte Rd., Duarte, Calif. Excerpt In radiographic installations of more than one x-ray unit the need to reproduce a film technic with different units makes it necessary that they be cross-calibrated. In standard practice the establishment of a film technic requires that visual examination be made of representative films for various anatomical structures. Because of possible inconsistencies in the physical calibration factors of x-ray units, as reported in a previous paper (1), the establishment of a set of technical factors for one apparatus would not necessarily apply to a second. The process of trial and error must be repeated with each one, and this results, in addition to the time and effort required, in undesirable patient exposure. In principle, the quality of a film depends on beam energy and intensity, with all other things being constant. A knowledge of these two factors for any individual apparatus, therefore, should suffice to establish radiographic technics based on an established technic chart for another unit. A system for providing this type of cross-calibration was suggested in the authors' earlier paper. Incidentally, the use of half-value layer and output determinations for the establishment of film technic is not limited to interdepartmental standardization. The possibility exists that other departments would also be able to duplicate film qualities by this means. Simply stated, an x-ray unit must first be calibrated for technical factors in the usual manner of visual evaluation. This unit serves as the standard and it is then possible to calibrate any additional units without application of visual methods, purely by virtue of the comparison of half-value layer and output. The situations in which calibration of radiographic installations becomes necessary include the following: ( a ) change of tubes or other parts of a unit, ( b ) replacement of an installation, and ( c ) the addition of new units to an existing department or the creation of an entirely new department. Method Three x-ray units were studied, the conditions under which measurements were made being maintained constant. Half-value layer determinations were made with aluminum filters with a Landsverk 200-mr pocket chamber calibrated for energy dependence at the Landsverk factory. The values were plotted for each of the units on a single graph, so that the effective kilovoltage for equivalent half-value layer could be readily determined (see Fig. 1). After half-value layer determinations were made, the output of each x-ray unit was measured with the Landsverk chamber at an equivalent kilovoltage as determined from the plot of half-value layers. A plot of output per 100 milliampere-seconds at equivalent kilovoltage is shown in Figure 2. After establishment of half-value layer and output equivalences, the next step was to take one of the units as a standard and establish a set of technics which produced visually acceptable roentgenograms. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Radiology Radiological Society of North America, Inc.

Loading next page...

You’re reading a free preview. Subscribe to read the entire article.

DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy unlimited access and
personalized recommendations from
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $40/month

Try 2 weeks free now

Explore the DeepDyve Library

How DeepDyve Works

Spend time researching, not time worrying you’re buying articles that might not be useful.

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from Springer, Elsevier, Nature, IEEE, Wiley-Blackwell and more.

All the latest content is available, no embargo periods.

See the journals in your area

Simple and Affordable Pricing

14-day free trial. Cancel anytime, with a 30-day money-back guarantee.

Monthly Plan

  • Read unlimited articles
  • Personalized recommendations
  • Print 20 pages per month
  • 20% off on PDF purchases
  • Organize your research
  • Get updates on your journals and topic searches


Best Deal — 25% off

Annual Plan

  • All the features of the Professional Plan, but for 25% off!
  • For the normal price of 10 articles elsewhere, you get one full year of unlimited access to articles.

billed annually