[ RadSafe ] Skin Injuries To Patients Can Be Avoided When Radiation Dose Is Monitored

[John Jacobus]

I am not sure about the PEMMET, but my understanding
is that you cannot buy x-ray units in Europe without a
DAP (dose area product) device.  Again, the values are
DAP values are not entrance skin doses, as the
measurements are made at the exit of the x-ray tube.
One needs to take into account the distance to the
skin surface.  

Skin dose and dose-area product values in patients
undergoing intracoronary brachytherapy.
 Br J Radiol.  2003; 76(901):32-8 (ISSN: 0007-1285)
Vano E; Prieto C; Fernandez JM; Gonzalez L; Sabate M;
Galvan C
Interventional Cardiology Service, San Carlos
University Hospital, 28040 Madrid, Spain.

Entrance skin doses, dose-area product (DAP) values,
fluoroscopy times and digital cine acquisition data
were measured for 86 patients undergoing intracoronary
brachytherapy procedures with beta sources, to
estimate risk of skin injuries. Interventions were
carried out in three dedicated X-ray interventional
cardiology rooms equipped with X-ray systems operating
in pulsed modes, with high filtration and edge filter
options. Skin dose distribution was analysed in detail
in 56 patients using slow films and thermoluminescent
dosimetry. Digital recording of Digital Imaging and
Communications in Medicine cine images also allowed
analysis of the technical parameters used throughout
the procedures. A protocol for clinical follow-up of
these patients at the cardiology service is also
presented, which prescribes special attention when a
threshold dose is reached. Median values for DAP,
fluoroscopy time and number of frames were 81.2 Gy
cm(2), 17.5 min and 1569 frames, respectively, and
maximum values were 323.3 Gy cm(2), 46.2 min and 3213
frames, respectively. In two cases, maximum skin doses
in a procedure reached 3.5 Gy and 4.6 Gy. Comparing
median values in this study, intracoronary
brachytherapy involved approximately two-fold the DAP
used in percutaneous transluminal coronary angioplasty
procedures performed during the same period in the
same catheterization laboratories, as a consequence of
the need to monitor the radioactive source location
used for the treatment of stenoses and the
intravascular ultrasound. Special care must be paid in
those cases of high dose in relation to potential
patient skin injuries and late effects.

http://www.medscape.com/medline/abstract/12595323

--- alstonchris at netscape.net wrote:

> Folks
> 
> Dr. Chida is mistaken, in principle.  The PEMNET
> system, which allows 
> real-time monitoring of both dose rate and
> cumulative dose in 
> fluoroscopy, has been available for many years.  One
> caveat: I don't  
> know that it's sold in Japan.
> 
> Cheers
> cja
> 
> 
> Angioplasty, is a procedure that helps treat
> narrowed coronary arteries.
> "Many patients benefit greatly from procedures such
> as angioplasty, 
> however,
> a major disadvantage associated with these
> procedures is patient 
> radiation
> exposure," said Koichi Chida, PhD, lead author of
> the study. "In most
> cardiac interventional procedures, real-time
> monitoring of maximum skin 
> dose
> is not possible," however monitoring total entrance
> skin radiation dose 
> is,
> Dr. Chida said.
>

+++++++++++++++++++
"If you guard your toothbrushes and diamonds with equal zeal, you'll probably lose fewer toothbrushes and more diamonds."
- Former national security advised McGeorge Bundy
-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com


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