[Oradlist] D-speed film

Allan G Farman agfarm01 at louisville.edu
Thu Feb 5 16:44:33 PST 2009


mmm! Yes, all systems seem to be capable of misuse to provide high dose
to the patient. I was in Nepal eight years ago and visited several
clinics. To my surprise Kodak F-speed film was being exposed at one
clinic for 3 seconds, then processed in"soap holders" in the semi-dark
for a matter of seconds. Current F-speed fils are only marginally faster
than the E-speed films they replaced as they fall in the slow end of the
F-speed range; whereas, E-speed fils tended to be at the fast end of the
E-speed range. D-speed film from Kodak is also at the fast end of the
range for the speed group. As both E and D speed films have been at the
fast end of the range, there was a 50% reduction in dose with a move
from D to E speed.... but there is only a 10-20% difference in moving
from E  to F. These suggested dose requirements are dependent on
processing chemicals and conditions.... and dose also depends upon the
practitioner's selection of mean film density, selection of the number
of images needed for a given diagnostic task, collimation and
filtration. I do not know whether a statistical test will make a 50%
difference in dose significant in a given test setting; however, I
certainly consider a 50% dose reduction clinically relevant given
uncertainly of affects of low doses of radiation.

Regarding digital imaging detectors, these can also be abused. With CCD
sensors, overdose led to pixel blooming and an obviously inadequate
result. With CMOS sensors, this is not the case; hence the recording
latitude can provide excellent images over a wide range of exposures...
including unnecessarily excessive exposure. This is also the case for
photostimulable phosphor imaging. While dose savings can be achieved
with some digital intraoral sensors, optimizing dose savings is
dependent upon the setting applied by the practitioner. Lazy
practitioners might well not bother to adjust exposure between different
parts of the mouth and then stretch the grayscale to "equalize" the
appearances. There are no guarantees that the lowest diagnostic dose
will actually be used.

Having said this, I personally would like to see D-speed intraoral film
disappear from the market, but also to have folk realize that ISO-speed
ratings are ranges with slow and fast versions of each letter speed.
Further, I would like folk to understand that there is more to radiation
dose minimization than just the designated speed of the receptor.

AGF

Allan G. Farman, BDS, PhD, MBA, DSc, Diplomate ABOMR

Prof. Radiology & Imaging Science
Univ. Louisville School of Dentistry: SUHD
501 South Preston Street,
Louisville, Kentucky 40292, USA 

Tel: +1(502) 852.1241
Fax: +1(502)852.1626


>>> Allan Abuabara <allan.abuabara at gmail.com> 02/05/2009 04:48 PM >>>
This recent article can help you.
Regards.

Allan Abuabara.
Joinville - SC, Brazil

*Dentomaxillofacial Radiology (2009) 38,* 92-97
http://dmfr.birjournals.org/cgi/content/abstract/38/2/92 
SHORT COMMUNICATION Is it true that the radiation dose to which
patients are
exposed has decreased with modern radiographic films? * M Alcaraz*,1,
C
Parra2, Y Martínez Beneyto2, E Velasco1 and M Canteras3 *

* 1Department of Radiology and Physical Medicine, Faculty of
Medicine/Dentistry, University of Murcia, Campus Espinardo, Spain;
2Department
of Stomatology, Faculty of Medicine/Dentistry, University of Murcia,
Campus
Espinardo, Spain; 3Department of Biostatistics, Faculty of
Medicine/Dentistry, University of Murcia, Campus Espinardo, Spain *

*Correspondence to: Department of Radiology and Physical Medicine,
Faculty
of Medicine/Dentistry, University of Murcia, 30100 * Campus de
Espinardo
(Murcia), Spain. E-mail: mab{at}um.es

Received 12 October 2007; revised 24 February 2008; accepted 6 March
2008

*Abstract*

*Objectives:* To determine whether the radiation dose administered to
patients has decreased with new radiographic films and digital imaging
systems.

*Methods:* A total of 10 171 off
icial reports on radiological practice
in
dental surgeries (covering the years 1996*2003) from 16 Spanish
autonomous
regions were studied, analysing the type of film used, the exposure
times
and the radiation doses administered in each dental clinic for four
different teeth: upper molar, lower molar, upper incisor and lower
incisor.

*Results:* The Agfa Dentus M2 radiographic film needed the longest
exposure
times for all of the teeth (0.6 s, 0.5 s, 0.4 s and 0.4 s,
respectively)
followed in decreasing order by Ultraspeed, Insight, Ektaspeed and the
digital systems, the decrease with respect to the first reaching as
much as
60%. Regarding the dose administered, Agfa Dentus M2 used the highest
dose
(3.1 mGy) followed by Ultraspeed (2.7 mGy), Insight (2.2 mGy),
Ektaspeed
(2.2 mGy) and, finally, the digital systems (1.1 mGy). Statistical
analysis
showed significant differences between the doses administered for the
digital systems with respect to the radiographic films (*P *< 0.001)
and
with respect to manual or automatic processing (*P *< 0.001). However,
there
were no significant differences in dose between the different types of
films
themselves, or between the radiographic developing processes
themselves
(manual and automatic).

*Conclusion:* Not even the use of the most sensitive of modern films
has
brought about a reduction of the dose administered to patients in
Spain.
Only digital systems, it seems, will bring about reduction in this
dose.

*Keywords:* radiography; intraoral; doses; radiation; film


On Thu, Feb 5, 2009 at 2:15 PM, Stelt, PF. van der
<P.vd.Stelt at acta.nl>wrote:

> Enough scientific publications exist to show that the diagnostic
> performance of F-speed is similar to that of D-speed. In my opinion,
the
> ALARA discussion can be rather short when you can use 25% of the
> radiation dose at the same cost.
>
> Best regards,
> Paul
>
> _________________________________________________
> Paul F. van der Stelt, DDS, PhD
> Professor of Oral and Maxillofacial Radiology
> Chairman Dept. of General and Specialised Dentistry
> Head Dept. of Oral and Maxillofacial Radiology
> Academic Center for Dentistry Amsterdam (ACTA)
> Louwesweg 1
> 1066 EA Amsterdam, the Netherlands
> tel.      : +31-20-5188 262        e-mail  : p.vdstelt at acta.nl 
> fax      : +31-20-5188 480       web    : www.radiology.acta.nl 
> _________________________________________________
>
>
> > -----Original Message-----
> > From: oradlist-bounces at lists.ucla.edu 
> [mailto:oradlist-bounces at lists.ucla.edu] On
> > Behalf Of Garnet Packota
> > Sent: Thursday, February 05, 2009 4:12 PM
> > To: Oradlist at lists.ucla.edu 
> > Subject: [Oradlist] D-speed film
> >
> > I have a meeting tomorrow with our provincial dental licencing
> authority
> > and staff from our provincial radiation safety unit.  The topics
we
> are
> > discussing include use of CBCT imaging and D-speed film.
> >
> > I am not totally clear what our radiation safety unit is thinking
in
> > regards to D-speed; at the very least, I am sure they are seeking
a
> > policy statement to discourage use of D-speed in favour of F-speed
and
> > digital imaging.  I wonder if they might be seeking a
recommendation
> to
> > ban its use.  In preparation for the meeting, one of their staff
sent
> me
> > a pdf file of an article on dental radiography from an online
> > publication called "DrBicuspid.com".  In the article, Drs. John
> Ludlow,
> > Allan Farman and Ted Parks are quoted.  Of course, I plan to go to
the
> > meeting with a summary of pertinent literature.
> >
> > Notwithstanding the fact that we all promote the ALARA principle,
I
> > would like to ask if anyone is aware of any policy statements,
> > recommendations, or guidelines from provincial, state or other
> licencing
> > authorities that specifically make reference to use of D-speed
film.
> >
> > Thanks in advance for any information you can provide.
> >
> > --
> > Dr. Garnet V. Packota
> > Oral and Maxillofacial Radiologist
> > Faculty of Dental Medicine
> > University of Saskatchewan
> >
> > Mailing address:      Dental Teaching Hospital
> >                       University of Saskatchewan
> >                       105 Wiggins Road
> >                       Saskatoon SK
> >                       S7N 5E4  CANADA
> > Telephone:            (306)-966-5068 or 5073
> > Fax:                  (306)-966-1795
> > e-mail:                       garnet.packota at usask.ca 
> >
********************************************************************
> >
> >
> > _______________________________________________
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> > Oradlist at lists.ucla.edu 
> > http://lists.ucla.edu/cgi-bin/mailman/listinfo/oradlist 
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>



-- 
Allan



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