[ RadSafe ] Myth or Fact? (Dental dose)

Yoshihiko Hayakawa yhayaka at tdc.ac.jp
Wed Aug 30 05:18:48 CDT 2006

Dear RADSAFE subscribers,

Thank you very much for the information provided by interested
subscribers. I’m not the initial submitter, but they are of value
for me.

It’s not the first time for me to access www.crcpd.org , as
(Mr. or Ms.?) Suleiman described, it’s the time to have a more
recent dental survey.

It’s the first time for me to access

As Mr. Don Parry described, D-speed, E-speed and F-speed films are
used in dental office. Eastman Kodak has brought the best dental
films to the world-wide market for many decades.

The D-speed film, which was five to six times faster than the
preceding film, was marketed in 1955. The first E-speed film, two
times faster than D, was in 1981. The second E-speed-film was in
1994. The F-speed film, 20 % faster than E, was in 2000. Two kinds
of E-film were gone now.

But it seems difficult that the champion capability/performance of
each film is brought out in some dental offices. The F-speed film
is practically similar with E-speed film in many dental offices.

It’s the first time for me to access the following websites;


Equipments operated at lower kV should be replaced with those
operated within the range 60 to 70 kV.
Focus to skin distances of 150 mm is still used in Japan.

I know great works accomplished by Dr. S. Julian Gibbs, Vanderbilt,
Nashville, but the data quoted is a little old and slightly high.

As indicated by Mr. Don Parry, the use of digital sensors has
possibilities of the dose reduction. For example, last decade the
ownership rate of digital sensor and image-processing system
increased from 0 % to around 30 % in Japan. I have no idea in
details of ownership rates in other countries.

The other “go-digital” revolution is coming. There are approx.
65,000 dental offices in Japan. The number of dental office, in
which a cone-beam Computed Tomography (CT) system was installed,
became at least 200 at the beginning of 2006 in Japan. Probably
it’s approx. 250 now. Also, within a coming decade, the
considerable number of rotational panoramic radiography equipments
will be replaced with cone-beam CT systems or added the function
of cone-beam CT examinations.

These trends will be taken into consideration by the next NEXT
survey of radiographic examinations in dental office.

Yoshihiko Hayakawa
Tokyo Dental College
mailto:yhayaka at tdc.ac.jp

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