Download X-Ray Intensive Medical Procedures Using a Standard

X-Ray Intensive Medical Procedures Using a Standard Fluoroscope and its Lowest
Automated Radiation Settings
Karikari IO, Brown CR, Anderson DG
Introduction:
Methods
Results:
The deleterious effects of ionizing radiation
are well established, with its cumulative
impact having known health risks both for
healthcare providers1-56,7 and
patients1,9.
This is of particular concern with respect to
fluoroscopically guided medical procedures,
as these rely on constant exposure to
radiation throughout the procedure. While
fluoroscopically guided procedures enhance
surgical accuracy and reduce surgical
morbidity, they do so at the cost of increased
radiation exposure.
A prospective, randomized cadaveric study
was undertaken to compare the utility and
radiation exposure experienced during a
fluoroscopically intensive medical procedure.
Physicians with experience in performing
kyphoplasties were asked to duplicate the
procedure in cadaveric specimens, imitating
precisely their routine when performing a
kyphoplasty in their daily practice. Each
surgeon repeated the procedure at one spinal
level using LessRay® enhanced imaging and
another using conventional fluoroscopy
unaided by enhancement. These were
performed at adjacent spinal levels, randomly
starting with conventional or reduced
radiation imaging. In the reduced radiation
case, though, the fluoroscope was set to the 1
pulse and low dose settings, the lowest
automated setting on a GE OEC 9900
fluoroscope. As well, the physicians were
blinded to the fluoroscope screen and only
allowed to use the LessRay® enhanced
images as long as they remained viable. At
any point, if the image clarity was not
sufficient to perform the procedure safely,
the physicians were allowed to increase the
radiation or look at the fluoroscope screen.
Seven spine surgeons performed fourteen
(14)
kyphoplasties
throughout
the
thoracolumbar spines of 2 human cadavers.
In no case did any of the physicians abandon
the LessRay® enhanced images.
The
average duration of fluoroscopy for the entire
procedure was 11.0s and 65.6s in the
LessRay® enhanced and conventional
fluoroscopy groups respectively (p<0.001).
Despite statistically similar number of
images with both methods prior to cement
injection (24 Conventional vs. 21 LessRay®assisted, p=0.30), the pulsed/low dosed
procedures achieved an overall 88.8%
radiation reduction over conventional
imaging (36.1mGy vs. 4mGy, p< 0.001).
Altering the dose settings and pulse rate on a
conventional
fluoroscope
are
simple
measures that can radically minimize this
exposure to ionizing radiation. These
techniques, advocated by the American
College of Radiology10 and the FDA11, can
reduce radiation usage more than 90% as
compared to conventional fluoroscopy12.
Unfortunately, the image quality is often
compromised
with
these
techniques,
rendering themineffective.13Despite this fact,
the FDA has clearly stated that“medical
imaging examinations should use techniques
that are adjusted to administer the lowest
radiation dose that yields an image quality
adequate for diagnosis or intervention (i.e.,
radiation doses should be "As Low as
Reasonably Achievable")11 – or ALARA.
Therefore physicians require technology that
allows greater utility of low radiation
imaging.
LessRay® is a computer display system that
caninterface with a standard fluoroscope to
enhance image resolution, allowing for a
greater ability to use the pulse and low dose
settings on a fluoroscope. It therefore offers
a physician the opportunity to use
significantly reduced radiation imaging in
any procedure that requires a fluoroscope,
and potentially better abide by the principles
of ALARA.
In this study, we assess the ability to use the
lowest automatic radiation settings on a
standard fluoroscope throughout the entirety
of a radiation intensive surgical procedure
when used in conjunction with LessRay.
Typically, the image quality of pulsed and
low dose images are not adequate to safely
perform a surgical intervention. Hence, we
are attempting to identify if poor quality
images could be improved by LessRay® to a
level considered adequate to perform the
procedure safely.
The number of images taken prior to cement
injection, seconds of fluoroscopy for the
entire procedure, and the amount of radiation
in mGy for the entire procedure were
recorded for each surgeon, as was the need to
convert to conventional imaging for better
clarity, if necessary. The amount of radiation
reduction was quantified as the percent
reduction. The chi-square test was used to
determine statistical significance. A p value
<0.05
was
considered
statistically
significant.
The Technology
LessRay® is a computer display system that
interfaces directly with the fluoroscope. The
captured images produced by the fluoroscope
are transmitted in real time to the LessRay®
computer where the images are enhanced and
then displayed on the LessRay® monitor.
LessRay® uses proprietary image processing
algorithms to post-process low-dose / pulsed
images, improving resolution and contrast to
provide a clinically valuable image to the
physician. This allows for greater utility of
low dose imaging. As the radiation needed to
obtain the image dictates the radiation
exposure to the patient and physician, using
low radiation images should strongly impact
this exposure.
When a pulsed and/or low dose image of this
shot is taken, they appear on the C-Arm
monitor as washed-out and grainy, but the
general form of the anatomy is faintly
apparent through the noise. LessRay®
embellishes this grainy image to make it
appear more like the original image taken
(see Figure I). As long as the image is of
the same anatomy in a similar orientation,
LessRay® will, in most cases,improve the
poor quality precursor from the C-Arm
monitor to a useable quality image on the
LessRay® monitor. This works for both
static images and continuous fluoroscopy,
which is key for a procedure like a
kyphoplasty which requires both.
Discussion:
Figure 1: A lateral view of the spine, taken during the study at 1
pulse and low dose settings, prior to (upper) and after (lower)
enhancement by LessRay®. Note the clarity of the anatomy
only once LessRay® improves the image.
Across nearly all surgical subspecialties,
minimally invasive (MIS) procedures are
becoming increasingly commonplace. While
the benefits have been lauded in numerous
studies13-16 they often require increased
radiation exposure due to the extensive
Note: In clinical practice, the amount of patient dose reduction achieved when a Pulse and/or Low Dose is improved with LessRay is dependent on the clinical task,
patient size, anatomical location and clinical technique. The dose should only be lowered to the level to which the physician is able to achieve the adequate image
quality needed for the particular clinical task. A consultation with a radiologist and a physicist may aid in determining the appropriate dose settings. imaging needed to make up for what is not
directly visualized at the time of surgery6,1721
. Although image guidance techniques
exist for some procedures, conventional
fluoroscopy remains the mainstay for
imaging in MIS procedures.
Radiation
exposure from fluoroscopy has known
significant medical risks, including concerns
for cataracts, CV disease, and most
worrisome, cancer1,8,9.
The cumulative
impact of this radiation exposure can quickly
result in a physician exceeding their yearly or
lifetime limits set by the National Council
on Radiation Protection 2 2 .
As dozens of the most common medical
procedures performed in the United States
are fluoroscopically dependent, the concern
for radiation over-exposure is most acute in
these procedures 16,17,19,21,23,24. Kyphoplasty
is a common surgical procedure thatis totally
dependent on fluoroscopic guidance, making
it an ideal radiation intensive procedure for
investigating radiation reduction strategies.
In their practice guideline for the
performance of vertebral augmentation, the
American College of Radiology (ACR)
presses the physician to use imaging during
these procedures in a manner “consistent
with
the
ALARA
radiation
safety
guidelines.”31
The options available for minimizing
radiation exposure include pulse and low
dose imaging. They can be employed with
standard fluoroscopy to reduce radiation over
90%12. When acquiring an image with
pulsed radiation, an 8 pulse image uses
essentially 8 times the radiation of a 1 pulse
image, and roughly 1/4 the radiation of
standard imaging settings12.
While this
technique is lauded by the ACR as one of the
most effective ways to decrease radiation10, it
often cannot be fully utilized in medical
procedures. Image clarity is negatively
affected
by decreasing the radiation
settings13. Each drop in pulse also causes a
drop in image quality.
Therefore, lower
pulse rate settings often do not produce
adequate image quality needed to safely
perform a procedure13.
In this study, all of the LessRay® procedures
were performed exclusively using one pulse
and low dose imaging (i.e. the lowest setting
on a conventional C-arm) without the need
to supplement these low quality images with
any standard dose images to ensure safety or
efficacy. The effectiveness of the LessRay®
technology was demonstrated by the
observation that no additional imaging was
needed when LessRay® was utilized.
Moreover there was no compromise in
surgical accuracy and no procedure was
aborted due to poor image quality.
The technique of lowering the ionizing
radiation emitted by the fluoroscope by
altering the pulse rate is not unique to this
study. Decreasing the pulse rate is strongly
advocated by the ACR and the Society for
Pediatric Radiology in their Image Gently
and Image Wisely campaigns10. It has been
employed in numerous studies, both
preclinical15,26 and clinical13,27-30 to address
radiation exposure. Although some neonatal
and pediatric studies have shown the ability
to lower the pulse rate down to less than 6pps
(pulses per second)26, no study focusing on
adults or adult anatomy has gone lower than
6pps13,26,28,2930Further, no study has gone to
1pps, and they typically do not include the
addition of low dose imaging. The reason for
this is probably best articulated in a recent
study of minimally invasive spine fusions
which sought to decrease radiation using
8pps in combination with low dose imaging
wherever image clarity allowed that
decrement in radiation. Unfortunately, "for
fine detail,” when required to perform the
procedure accurately, because the "detail of
the pedicle is lost with the low-dose pulsed
fluoroscopy,” the authors required steering
away from that technique13. It should be
noted that identifying accurately the borders
of the pedicle is required in exactly the same
fashion in performing the surgical
intervention used in this paper, yet image
enhancement allowed our physicians to
continue to perform the procedure throughout
at a lower radiation setting than their 8pps
and not abandon it when anatomic detail was
required.
Conclusions:
By digitally improving low radiation images,
this study demonstrates that LessRay®
allows entire procedures to safely be
performed using the lowest automated
radiation settings on a fluoroscope. The
procedure can progress as the physician
desires without altering the steps or the
number of images. Setting the C-arm to one
pulse and a low dose decreases radiation
emitted by an order of magnitude. LessRay®
makes these images useful. Together, they
are a powerful combinationresulting in a
safer environment for everyone in the
operating room.
1.
2.
3.
4.
5.
6.
7.
Hoffman DA, Lonstein JE, Morin MM, Visscher W,
Harris BS, 3rd, Boice JD, Jr. Breast cancer in women
with scoliosis exposed to multiple diagnostic x rays.
Journal of the National Cancer Institute.Sep 6
1989;81(17):1307-1312.
Adams MJ, Hardenbergh PH, Constine LS, Lipshultz
SE. Radiation-associated cardiovascular disease.
Critical
reviews
in
oncology/hematology.
2003;45(1):55-75.
Freedman DM, Sigurdson A, Rao RS, et al. Risk of
melanoma among radiologic technologists in the
United States. International journal of cancer.
Journal international du cancer. Feb 10
2003;103(4):556-562.
Mohan AK, Hauptmann M, Freedman DM, et al.
Cancer and other causes of mortality among
radiologic technologists in the United States.
International journal of cancer. Journal international
du cancer. Jan 10 2003;103(2):259-267.
Yoshinaga S, Mabuchi K, Sigurdson AJ, Doody MM,
Ron E. Cancer Risks among Radiologists and
Radiologic Technologists: Review of Epidemiologic
Studies. Radiology. 2004;233(2):313-321.
Chou LB CS, Harris AH, Tung J, Butler LM.
Increased breast cancer prevalence among female
orthopedic surgeons. Journal Womens Health.
2112;21(6):683-689.
Fisher BHaR. Influence of a prolonged period of lowdosage xrays on the optic and ultrastructural
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
appearances of cataract of the human lens. Br J
Opthalmol. 1979;63(7):457-464.
Brenner DJ HE. Computed Tomography--An
Increasing Source of Radiation Exposure. The New
England
Journal
of
Medicine.
Nov
29
2007;357(22):2277-2284.
Balter S HJ, Miller DL, Wagner LK, Zelefsky MJ.
Fluoroscopically guided interventional procedures: a
review of radiation effects on patients' skin and hair.
Radiology. February 2010;254(2):326-341.
Hernanz-Schulman M GM, Bercha IH, Strauss KJ.
"Pause and Pulse: Ten Steps That Help Manage
Radiation Dose During Pediatric Fluoroscopy".
American Journal of Radiology. 2011(197):475-481.
Administration
UFaD. Initiative to
Reduce
Unnecessary Radiation Exposure from Medical
Imaging.
2010;
http://www.fda.gov/RadiationEmittingProducts/RadiationSafety/RadiationDoseRed
uction/ucm199994.htm.
Healthcare G. Hitting the Mark With Dose. 2008;
http://www.gehealthcare.com/usen/xr/surgery/docs/hit
_mark_dose_power.pdf.
Clark JC JG, Marciano FF, Tumialán LM. Minimally
invasive transforaminal lumbar interbody fusions and
fluoroscopy: a low-dose protocol to minimize
ionizing radiation. Neurosurg Focus. 2013;35(2).
Harrington JF FP. Open versus minimally invasive
microdisectomy:
comparison of operative times,
length of hospital stay, narcotic use, and
complications.
Minima
Invasive
Neurosurg.
2008;2008(51):30-35.
Jae Hun Cho M, Jae Yun Kim, MD, Joo Eun Kang,
MD, Pyong Eun Park, MD, Jae Hun Kim, MD, Jeong
Ae Lim, MD, Hae Kyoung Kim, MD, and Nam Sik
Woo MD. A Study to Compare the Radiation
Absorbed Dose of the C-Arm Fluoroscopic Modes.
The Korean Journal of Pain. 2011;24(4):199-204.
Theocharopoulos N PK, Damilakis J, Papadokostakis
G, Hadjipavlou A, Gourtsoyiannis N. Occupational
exposure from common fluoroscopic projections used
in orthopaedic surgery. . J Bone Joint Surg
Am003;85(A (9)):1698-1703.
Efstathopoulos EP, Pantos I, Andreou M, et al.
Occupational radiation doses to the extremities and
the eyes in interventional radiology and cardiology
procedures. The British journal of radiology. Jan
2011;84(997):70-77.
Ron E JP. Late health effects of ionizing radiation:
bridging the experimental and epidemiologic divide.
Radiati Res. Dec 2010;174(6):789-792.
Sinnott B RE, Schneider AB. Exposing the thyroid to
radiation: a review of its current extent, risks, and
implications. Endocr Rev. Oct 2010;31(5):756-773.
Martha S. Linet TLS, Donald L. Miller, Ruth
Kleinerman, Choonsik Lee, Preetha Rajaraman, Amy
Berrington de Gonzalez. Cancer Risks Associated
with External Radiation From Diagnostic Imaging
Procedures. CA Cancer J Clin. Feb 3 2012;62(2):75100.
G. S. Occupational radiation exposure to the surgeon.
Journal American Academy of Orthopedic Surgery.
2005;13(1):69-76.
(U.S.) NCoRPaM. Review of the current state of
radiation protection philosophy : recommendations of
othe National Council on Radiation Protection and
Measurements. . 1975;Publication No. 43.
Gledo I, Pranjic N, Drljevic K, Prasko S, Drljevic I,
Brzezinski P. Female breast cancer in relation to
exposure to medical iatrogenic diagnostic radiation
during life. Contemp Oncol (Pozn). 2012;16(6):551556.
Brown KR, Rzucidlo E. Acute and chronic radiation
injury. Journal of vascular surgery. Jan 2011;53(1
Suppl):15S-21S.
Long SS, Morrison WB, Parker L. Vertebroplasty and
kyphoplasty in the United States: provider distribution
and guidance method, 2001-2010. AJR. American
journal of roentgenology. Dec 2012;199(6):13581364.
Ward VL BC, Strauss KJ, Lebowitz RL,
Venkatakrishnan V, Stehr M, McLellan DL, Peters
CA, Zurakowski D, Dunning PS, Taylor GA.
Radiation exposure reduction during voiding
cystourethrography in a pediatric porcine model of
vesicoureteral reflux. Radiology. 2006;238(1):96-106.
Rogers DP EF, Lozhkin K, Lowe MD, Lambiase PD,
Chow AW. Improving safety in the electrophysiology
laboratory using a simple radiation dose reduction
strategy: a study of 1007 radiofrequency ablation
procedures. Heart. 2011;97(5):366-370.
Georges JL, Livarek B, Gibault-Genty G, et al.
Reduction of radiation delivered to patients
undergoing invasive coronary procedures. Effect of a
programme for dose reduction based on radiationprotection training. Archives of cardiovascular
diseases. Dec 2009;102(12):821-827.
Greene DJ, Tenggadjaja CF, Bowman RJ, Agarwal G,
Ebrahimi KY, Baldwin DD. Comparison of a reduced
radiation fluoroscopy protocol to conventional
fluoroscopy during uncomplicated ureteroscopy.
Urology. Aug 2011;78(2):286-290.
M. H-S. Science to practice: can fluoroscopic radiation dose
be substantially reduced? Radiology. Jan 2006;238(1):1-2.
http://www.acr.org/~/media/ACR/Documents/PGTS/
guidelines/Vertebral_Augmentation.pdf
Note: In clinical practice, the amount of patient dose reduction achieved when a Pulse and/or Low Dose is improved with LessRay is dependent on the clinical task,
patient size, anatomical location and clinical technique. The dose should only be lowered to the level to which the physician is able to achieve the adequate image
quality needed for the particular clinical task. A consultation with a radiologist and a physicist may aid in determining the appropriate dose settings.