Washington, D.C. (July 15, 2010) -- Next week the city of
Philadelphia will host the 52nd annual meeting of the American
Association of Physicists in Medicine (AAPM), the premier
organization in medical physics, a broadly-based scientific and
professional discipline encompassing physics principles and
applications in medicine and biology.
Many of the presentations and symposia at the meeting are
focused on patient safety -- tailoring therapy to the specific
needs of people undergoing treatment, adding safeguards to enhance
quality assurance, and finding ways to image children and adults
safely at lower radiation exposures while maintaining good image
quality, and more.
Some of the highlights of these presentations are listed below.
Journalists are invited to attend the meeting for free. The meeting
lasts from July 18 - 22, 2010, and registration information appears
at the end of this release.
PATIENT SAFETY HIGHLIGHTS FROM THE MEETING
- Special Symposium: Medical Radiation and Patient Safety
- Reducing Radiation Dose -- and Future Cancer Risk -- in
Pediatric Patients
- Risk of Radiation-Induced Cataracts Among Cardiologists
- Cancer Risks From Radiation Should Include Age, Sex
- IAEA "Smart Card" Effort to Create Radiation Passports
- From "Step and Shoot" to a Smooth Spiral -- Evolving CT Dose
Assessment
- Medical Scanners Get a Check-Up
- Time Out Procedures Reduce Error Rates
- One Canadian Hospital's Encouraging Results Reducing Radiation
Dose
- Safety Science: Emergency Off Systems
- New Data Management System Helps Promote Patient Safety
- Risks of Accurate Therapy -- Making Radiation Safer for
Pediatric Patients
- Other Presentations of Interest
- More Meeting Information
1) SPECIAL SYMPOSIUM: MEDICIAL RADIATION AND PATIENT
SAFETY
Recent radiation overdoses at three Los Angeles-area hospitals
and one hospital in Alabama have thrown a public spotlight on the
safety of procedures involving medical radiation. New efforts to
improve patient safety are the focus of a special symposium at the
52nd AAPM meeting that brings together an investigative journalist
and medical physicists. Recent technical failures and human errors
will be addressed in light of new AAPM recommendations and IAEA
efforts to provide better education and accreditation for staff,
consistent systems for reporting medical errors, and a more
comprehensive assessment of medical technologies by the FDA.
The discussion will take place from 2-4 p.m. EDT on Sunday, July
18. Speakers include:
- Walt Bogdanich, an investigative reporter for the New York
Times, who will discuss his recent series of articles on radiation
accidents
- William Hendee, professor at the Medical College of Wisconsin
and editor of the journal Medical Physics, who will present safety
recommendations developed at the AAPM symposium "Safety in
Radiation Therapy -- A Call to Action" in June
- Michael Herman, professor at the Mayo Clinic and president of
AAPM, who will describe ongoing efforts by the AAPM to improve
patient safety, including dialogues with the FDA
- Ola Holmberg, head of the Radiation Protection of Patients
(RPoP) unit at the International Atomic Energy Association, who
will discuss IAEA efforts to prevent radiation accidents.
The "Special Symposium on Patient Safety" will be at 2:00 p.m.
on Sunday, July 18, 2010 in Ballroom A of the Pennsylvania
Convention Center.
ABSTRACT:
http://www.aapm.org/meetings/amos2/pdf/49-14600-67969-790.pdf
2) Reducing Radiation Dose -- and Future Cancer Risk -- in
Pediatric Patients
PHILADELPHIA, PA (July 18, 2010) -- Children with cancer are
monitored regularly, but can there be too much of a good thing?
According to Dianna Cody, a professor of imaging physics at the
University of Texas, M.D. Anderson Cancer Center in Houston, many
children who survive cancer have a higher than average chance of
developing a second cancer later in their lives.
"And we don't know," she says, "if that is because they have a
genetic predisposition, or if it was due to the chemotherapy, the
radiation therapy, or the diagnostic imaging. We want to reduce the
risk of future cancer due to our component." The radiation exposure
due to tumor imaging can be substantial, she adds, as some children
are screened as often as every three months.
Cody and her colleagues will present results of a study aimed at
reducing radiation exposure in pediatric patients today at the 52nd
meeting of the American Association of Physicists in Medicine
(AAPM) in Philadelphia.
Cody and her team took what she says were "logical steps." The
CT (computed tomography) scanners used to visualize tumors are
capable of modulating their radiation output based on the amount of
tissue being scanned, ramping up in areas of relatively thick
tissue such as the torso and tamping down in thinner areas such as
the neck. Rather than having the machine operate at a static level
throughout the process, the researchers instructed the machine to
deliver a certain quality and then stepped back, allowing the
instrument to "dial" itself up or down. They also consulted closely
with the radiologists responsible for reading the CT images, to
work on how high an image quality was actually necessary to make a
clinical determination; that is, how much "noise" could be accepted
before the tumor "signal" would be unreadable.
In an initial group of eight cases, the investigators were able
to demonstrate that a reduction of radiation exposure by 23 percent
could be achieved without compromising quality medical care.
The presentation "Our Experience Reducing CT Radiation Dose to
Pediatric Populations" by K Mathieu, N Fitzgerald, and D Cody will
be at 3:00 p.m. on Sunday, July 18, 2010 in the Exhibit Hall on
Level One of the Pennsylvania Convention Center.
ABSTRACT:
http://www.aapm.org/meetings/amos2/pdf/49-12996-5072-477.pdf
3) RISK OF RADIATION-INDUCED CATARACTS AMONG
CARDIOLOGISTS
PHILADELPHIA, PA (July 21, 2010) -- Some cardiologists who use
fluoroscopy to image patients can be exposed to higher doses of
radiation than radiologists. One danger for those exposed to higher
levels of radiation is an increased level of eye cataracts.
Believing that interventional cardiologists and nurses who work
in places where radiation protection protocols might not be fully
employed are especially at risk, Madan Rehani and his team at the
International Atomic Energy Agency (IAEA) in Vienna have
investigated possible cataract links for catheterization
laboratories staff in Bogota, Columbia; Montevideo, Uruguay; Kuala
Lumpur, Malaysia; and Sofia, Bulgaria.
Rehani and his team, interviewed cardiologists and nurses in
these cities, and eye specialists examined their eyes. They found
that among cardiologists, 52 percent had developed some opacity in
the lenses of their eyes; for nurses it was 45 percent, and for a
control group it was 9 percent.
Rehani cautions that even though the correlation between
radiation dose exposure and prevalence of lens change was high, a
larger sample size needs to be tested to pin down the relation
between dose and cataracts
Nevertheless, he says, "Radiation protection rules should be
obeyed, as cataracts were observed at radiation levels lower than
what are currently believed to cause cataracts.
The presentation "IAEA Study of Cataract in Staff Working in
Catheterization Laboratories" by M Rehani will be at 8:30 a.m. on
Wednesday, July 21, 2010 in Room 202 of the Pennsylvania Convention
Center.
ABSTRACT:
http://www.aapm.org/meetings/amos2/pdf/49-14431-74473-551.pdf
4) Cancer Risks From Radiation Should Include Age,
Sex
PHILADELPHIA, PA (July 19, 2010) -- The technique currently used
in hospitals across the country to assess the cancer risk
associated with CT scans doesn't take into account a patient's age
or sex. But it should, according to Walter Huda of the Medical
University of South Carolina in Charleston, who will present data
today at the 52nd meeting of the American Association of Physicists
in Medicine (AAPM) suggesting that these factors can have a
significant impact on risk.
CT scans image the human body with X-ray radiation that can
increase a person's chance of getting cancer. Radiologists estimate
this risk with a number called an effective dose -- a calculation
that includes both the dosage received by different tissues in the
body and the sensitivity of different organs to these doses.
A typical chest X-ray scan might have an effective dose of 0.02
millisieverts. A CT scan of the abdomen, about 8 millisieverts.
"The assumption is often that a millisievert is a millsievert is
a millisievert," says Huda. "But it's a very crude indicator of
patient risk that can overestimate or underestimate your actual
risk."
Using data from the National Research Council's committee on the
Biological Effect of Ionizing Radiations (BIER), the most
authoritative source on radiation risks, Huda investigated other
factors that could impact a patient's risk.
He found that risk levels depended on the type of procedure
being performed.
"A pelvic CT scan, an abdomen CT scan, or a chest CT scan might
all have effective doses of 10 millisieverts, but the risks for
each of those doses could vary by a factor of two or three," says
Huda.
The sex of the person being scanned was also important. On
average, a chest CT scan was 2.6 times riskier for women than men
-- while a pelvic scan was 11 percent safer.
The age of a person had the biggest effect. Compared to an
80-year-old, the risk levels for a 20-year-old were five times
higher in men and six times higher in women.
The presentation " How Well Do Effective Doses Predict
Carcinogenic Risks in Body CT?" by W He and W Huda will be at 5:10
p.m. on Monday, July 19, 2010 in Room 204B of the Pennsylvania
Convention Center.
ABSTRACT:
http://www.aapm.org/meetings/amos2/pdf/49-12725-73639-142.pdf
5) IAEA "SMART CARD" EFFORT TO CREATE RADIATION
PASSPORTS
PHILADELPHIA, PA (July 22, 2010) -- Patients going from one
radiology facility or one doctor to another, or indeed moving from
one country to another, can leave a confusing trail of
documentation about radiation exposure in radiological
examinations. M. Rehani, who works at the International Atomic
Energy Agency (IAEA) in Vienna, Austria, will report today at the
52nd meeting of the American Association of Physicists in Medicine
(AAPM) on efforts to develop an international system for tracking
patient exposures. The idea was first broached in 2001 but became
an active program only around 2008.
Called a Smart Card/SmartRadTrack, the system ultimately may be
something like an ATM card. It does not contain money on it but
allows one to use the card to access money and account details. For
the patient, radiation exposure history is sufficient whereas for
health authorities radiation dose information is needed. Aggregate
data obtained through the eHealth system would enable countries to
establish radiation and exposure standards and help in future
epidemiological studies. This would require manufacturers to
develop equipment and software for tracking procedures and
doses.
The presentation " IAEA Smart Card Initiative for Patient
Exposure" by M Rehani will be at 8:30 a.m. on Thursday, July 22,
2010 in Room 202 of the Pennsylvania Convention Center.
ABSTRACT:
http://www.aapm.org/meetings/amos2/pdf/49-14438-62523-620.pdf
6) From "Step and Shoot" to a Smooth Spiral -- Evolving CT
Dose Assessment
PHILADELPHIA, PA (July 20, 2010) -- CT scanning has undergone
radical changes during its thirty-plus years in clinical use, but
the way radiation dosage associated with scanning is assessed has
not kept pace. That may change shortly, according to Dianna Cody,
Ph.D., a professor of imaging physics at the University of Texas,
M.D. Anderson Cancer Center in Houston.
"Current methods are not optimal," notes Cody, who said the
methods used to calculate patient exposure are based on original CT
(computed tomography) machines, which required that the object of
analysis travel through the instrument's field in small increments.
After each small movement, the machine took a reading – what
investigators termed a "step and shoot" approach. These snapshots
were then compiled to obtain the complete exam. Manufacturers have
made great strides, however, and currently take continuous
readings, collecting data in a spiral mode.
But determination of radiation exposure is still arrived at by
assuming the patient is exposed in a planar mode and making
mathematical adjustments to the calculation. Since CT is used for
many types of medical diagnosis, and some patients being treated
for conditions as diverse as cancer and kidney stones receive
repeated exposure to the technique, a more straightforward and
accurate means is desired by those in the field. This more direct
method to assess radiation dose was developed by Robert Dixon,
Ph.D., a professor at Wake Forest University in Winston Salem,
North Carolina; it is becoming accepted as the CT dose assessment
choice for the future.
Today at the 52nd meeting of the American Association of
Physicists in Medicine (AAPM) in Philadelphia, Cody and her
colleagues will cover this new approach based on modern CT
scanners' helical motion around a center point in the field. She
doesn't expect any new standard to be adopted immediately, she
says. Rather, she expects it would "take a while for everyone to
converge, and we'll probably be using both approaches for a while
until a transition is made."
The presentation "Current and Future Measurements of CT Dose" by
D Cody will be at 1:55 p.m. on Tuesday, July 20, 2010 in Room 201B
of the Pennsylvania Convention Center.
ABSTRACT:
http://www.aapm.org/meetings/amos2/pdf/49-14529-33931-56.pdf
7) Medical IMAGING SYSTEMS Get a Check-Up
PHILADELPHIA, PA (July 19, 2010) -- Patients aren't the only
ones getting check-ups in hospitals. The medical scanners that
radiologist use to peer into the human body must be periodically
tested to make sure that they are functioning efficiently and to
minimize the radiation doses received during a scan.
Currently, no common standard exists for testing scanners used
for digital radiography. Different healthcare facilities use
different, subjective procedures.
"There are inconsistencies between hospitals, and it can be
difficult to assess which machines are actually performing well,"
says Andrew Kuhls-Gilcrist of the University at Buffalo, N.Y.
Today at the 52nd Annual Meeting of the American Association of
Physicists in Medicine (AAPM) in Philadelphia, Kuhls-Gilcrist and
his colleagues in Professor Stephen Rudin's group at the UB Toshiba
Stroke Research Center will describe how they have developed one
possible solution -- a standard calibration method that bridges the
gap between the laboratory and the clinic. They've adapted the
precise techniques used by scientists to test new scanner
technologies into a simple, effective procedure suitable for a
bustling healthcare facility.
"If it's not easy, if it's not accurate, no one is going to use
it," says Kuhls-Gilcrist, who is the AAPM Junior Investigator
Winner.
The procedure takes about ten minutes. A radiologic technologist
pushes the button on the X-ray equipment to acquire a few "blank"
images. Then a computer program automatically analyzes the noise in
these images and calculates a range of quantitative measurements
such as the detective quantum efficiency, which indicates how
effectively a scanner uses each dose of radiation. Other
measurements of instrument noise check for problems that could
affect the image quality of low-dose procedures such as
fluoroscopy.
This method of quality assurance procedure has proven to be just
as accurate as tests used by scientists in the laboratory, in which
expensive, precisely-fabricated objects with near-perfect straight
edges are imaged.
The presentation, "A New Simple, Accurate, and Quantitative
Approach for Routine Quality Assurance in Digital Radiography" by A
Kuhls-Gilcrist, D Bednarek, and S Rudin will be at 4:00 p.m. on
Monday, July 19, 2010 in Room 204B of the Pennsylvania Convention
Center.
ABSTRACT:
http://www.aapm.org/meetings/amos2/pdf/49-12777-99871-601.pdf
8) Time Out Procedures Reduce Error Rates
PHILADELPHIA, PA (July 22, 2010) -- Imagine the following
announcement: "Our patient is Ken Chu. We are amputating his left
arm. Does everybody agree?"
Welcome to a hypothetical "Time Out" (TO) statement and question
set, a standard operating room procedure among surgeons to reduce
errors by assuring the patient receives the correct treatment.
And now Ken Chu, PhD—who happily has both arms and is
Chief Medical Physicist at Marquette General Hospital in
Michigan—has conducted a study whose data argue for extending
the TO requirement to radiation oncology operators nationwide. He
will present this work today at the 52nd meeting of the American
Association of Physicists in Medicine (AAPM) in Philadelphia.
"This simple procedure of taking the time to say, 'Correct
patient name?…birthday?...treatment site?...dose?...gantry
angle? Do you agree?' If it's all good, then you beam on," explains
Chu.
Results show implementing TOs led to a threefold reduction in
radiation errors. To implement TOs takes just 15 seconds of verbal
discussion per radiation beam.
Dr. Chu reviewed radiation error records from five different
cancer centers in New York and Michigan over 2000-2009. During that
period, TO protocols were adopted at all centers, allowing him to
compute error rates before and after TO implementation.
Says Dr. Chu: "This is an amazingly powerful safety assurance
check that hospitals administrators would support since it is
already implemented in other areas of the hospital to reduce
errors."
The presentation "Implementation of a "time Out" Procedure in
Radiation Oncology: A Multi-Institution Study Over Nine Years
Results in a Three-Fold Reduction in Misadministrations" by B
Rasmussen and K Chu will be at 10:36 a.m. on Thursday, July 22,
2010 in Room 203 of the Pennsylvania Convention Center.
ABSTRACT:
http://www.aapm.org/meetings/amos2/pdf/49-12987-2450-892.pdf
9) One Canadian Hospital's Encouraging Results Reducing
Radiation Dose
PHILADELPHIA, PA (July 21, 2010) -- Late last year, after a
number of stories on diagnostic medical CT scanning began appearing
in newspapers, more and more people began to express concern about
their procedures and to inquire about dangers of X-ray radiation,
recalls Elena Tonkopi, a medical physicist at Queen Elizabeth II
Health Sciences Center in Halifax, Nova Scotia.
When an increasing number of these calls coming her way, Tonkopi
was prepared to answer them. "If patients are worried," she says.
"They need to hear from somebody who can provide them with
information." All the radiologists, technologists and medical
physicists in her department are conscious of radiation exposures,
she adds, and they all support strategies aimed at reducing
dose.
In fact, when the calls started coming in, she was just
completing a project with her colleagues Dr. Andrew Ross and Anita
MacDonald to increase safety for patients by optimizing and
lowering the CT radiation dose that patients receive while
undergoing PET/CT examination -- a common procedure for cancer
staging
Today at the 52nd Annual Meeting of the American Association of
Physicists in Medicine (AAPM) in Philadelphia, Tonkopi will
describe the results of that effort. Using nothing but available
techniques for protocol optimization provided by the manufacturer,
her department gradually lowered the average CT dose for patients
undergoing PET/CT by about one third (32 percent) without
sacrificing image quality -- something that can suffer if dose is
lowered too much.
"It was interesting to compare the studies of the patients who
had examinations before and after this optimization," Tonkopi said,
calling the results "encouraging." She added that they may lead
other institutions to follow suit. Before beginning the
optimization experiment, her colleague Dr. Ross, who is Division
Head Nuclear Med at Queen Elizabeth II Health Sciences Center,
contacted several other medical centers in Canada that offer PET/CT
and found that they expected about the same level of dose for the
same procedures.
The presentation "CT Radiation Dose Optimization in Whole-Body
PET/CT Examination by E Tonkopi, A Ross, and A MacDonald will be at
5:10 p.m. on Wednesday, July 21, 2010 in Room 201C of the
Pennsylvania Convention Center.
ABSTRACT:
http://www.aapm.org/meetings/amos2/pdf/49-13026-36971-93.pdf
10) Safety Science: Emergency off systems
PHILADELPHIA, PA (July 18, 2010) -- In all interactions with
technology, rigorous safety standards are imperative. But so is
practicality -- and sometimes the two aren't joined.
Physicists at the University of Alabama in Birmingham emphasize
this point in their statistical study of Emergency Off Systems
(EOS) procedures for computer-controlled linear accelerators that
deliver radiation cancer treatments in hospitals. Some states
require EOS of accelerators to be tested at exactly three-month
intervals, to the calendar day. But the researchers' results show
EOS tests performed on any day within the 3rd month after the last
check pose no significant risk to patients. And it would certainly
be more practical by reducing staff stress.
"A safety regulation can actually be counter productive when it
creates a false feeling of security -- and also, because it diverts
resources from other areas," explains Ivan Brezovich, PhD, director
in the Division of Radiation Physics and the lead investigator on
the study, which he and his colleagues are presenting today at the
52nd Annual Meeting of the American Association of Physicists in
Medicine (AAPM) in Philadelphia.
"Regulators need to consider both the short-term and
extended-term impacts of a safety policy," Brezovich adds.
The presentation "Safety Considerations Concerning the
Scheduling of Emergency Off Switch Tests" by I Brezovich and R
Popple will be at 10:24 a.m. on Thursday, July 22, 2010 in Room 203
of the Pennsylvania Convention Center.
ABSTRACT:
http://www.aapm.org/meetings/amos2/pdf/49-13500-88849-73.pdf
11) New Data Management System Helps Promote Patient
Safety
PHILADELPHIA, PA (July 18, 2010) -- Every 20 seconds, somebody
in the United States is diagnosed with cancer, and each year
hundreds of thousands of people will discuss possible next steps
with their doctors and decide to undergo treatment with radiation
therapy. This overarching decision, once reached, sets the wheels
in motion for the treatment team, as doctors, nurses, medical
physicists, technologists, and other specialists work together to
devise and carry out the best treatment plan possible for each
patient. That's how it's supposed to work.
Now a team of medical physicists at Washington University School
of Medicine has developed a new web-based infrastructure that they
say will enhance the current quality management paradigm and help
to improve safety for patients by collecting, analyzing, and
interpreting all the data related to the treatment. This includes
data on machine performance, software performance, and more in one
centralized database that can be accessed anywhere at any time
during the treatment process. They call this system Quality
Assurance Information System (QAIS). Currently, patient records in
many hospitals and clinics often reside partly on paper and partly
electronically -- and sometimes on multiple machines that can't
access one another.
"The idea is to make the whole system electronic," explains
Washington University medical physicist Dharanipathy Rangaraj, who
will describe the new system today at the 52nd Annual Meeting of
the American Association of Physicists in Medicine (AAPM) in
Philadelphia. "The electronic environment for QA data would
facilitate solving several challenges in quality assurance in
radiation therapy," he says.
Rangaraj and his colleagues envision that their new system QAIS
will make many things easier by facilitating opportunities to
develop tools such as an automated electronic chart plan checking
(EcCk) tool, an automated machine log file analysis tool (DynaQA)
for every treated beam, an automated QA plan generation tool to
reduce errors and variability, and workflow monitoring to evaluate
system status, collecting errors and near misses as they occur to
improve organizational learning. Also it would facilitate record
keeping, auditing, and assurance of hospital, state, and federal
compliance. The system is also designed to enhance safety and
quality for each individual patient by incorporating automated
alerts and warnings and by allowing users to access the data and
check patient charts at any step of a procedure in ways that
otherwise would not necessarily be available.
"Infrastucture such as QAIS should help institutions and private
clinics to understand the treatment practices, determine best
practice, benchmark practices and ultimately standardize health
care treatment in radiation therapy," Rangaraj adds. "We are in a
verge of a QA revolution in radiation oncology and QAIS is a step
in the right direction."
The presentation " An Infrastructure Towards Better and Safer
Radiation Therapy- Quality Assurance Information System (QAIS)" by
D Rangaraj, K Moore, L Santanam, S Yaddanapudi, D Yang, S Goddu, R
Brame, S Mutic, and D Low will be at 3:00 p.m. on Sunday, July 18,
2010 in the Exhibit Hall on Level One of the Pennsylvania
Convention Center.
ABSTRACT:
http://www.aapm.org/meetings/amos2/pdf/49-14261-67279-23.pdf
12) Risks of Accurate Therapy -- Making Radiation Safer for
Pediatric Patients
PHILADELPHIA, PA (July 18, 2010) -- Visualization of tumors can
guide radiation therapy in a specific and effective manner, but the
methods used to image and direct therapy typically themselves
involve radiation. This is particularly a concern in pediatric
patients, because they are far more susceptible than adults to
radiation-induced late effects such as growth retardation and
second malignancies.
Jun Deng, Ph.D., an associate professor of therapeutic radiology
at the Yale University School of Medicine, will present at the 52nd
meeting of the American Association of Physicists in Medicine
(AAPM) in Philadelphia today results that detail how much radiation
children are exposed to and how it might be reduced.
Deng and his colleagues examined a common imaging technique
known as kVCBCT (for kilo-voltage cone beam computed tomography)
used for tumor localization during image-guided radiation therapy.
Although kVCBCT is frequently applied nowadays, sometimes daily or
more for certain lesions, there are currently no commercially
available tools to calculate radiation exposure for kVCBCT scans.
Deng and his colleagues used a Monte Carlo simulation code
developed specifically for the purpose to monitor exposure in four
pediatric patients. They found that kVCBCT imaging delivered
"considerably larger doses" to critical organs and bony structures
in children, by a factor of 2 to 3 times more than in adults. A
typical kVCBCT imaging procedure in children can result in a dose
to certain organs that is equivalent to about 5000 chest x-rays,
and during a several week course of daily radiation treatments, the
imaging procedure may be repeated many times.
"Image guided radiation therapy is the way to go," Deng says,
emphasizing that the increased accuracy with imaging makes it
possible to eradicate some tumors that may not be curable
otherwise. But, he says, it is essential to evaluate and
incorporate the doses induced by imaging as part of the treatment
plan and to carefully choose an appropriate scanning protocol for
kVCBCT, in order to minimize late effects due to unwanted radiation
to nearby organs at risk while maximizing cure. Many of these
radiation-induced side effects occur several years after
irradiation, which may not be a serious concern for the elderly
adults but is critical for children.
"Many pediatric patients survive their primary cancers and have
a long life ahead of them," says Deng. "Therefore, we must include
imaging doses in treatment plans to ensure that the pediatric
patients have a good quality of life after radiotherapy."
The presentation "Investigation of KV Imaging Doses in the
Radiotherapy of Pediatric Cancer Patients by J Deng, Z Chen, K
Roberts, and R Nath will be at 1:30 p.m. on Sunday, July 18, 2010
in Exhibit Hall - Area 4 on Level One of the Pennsylvania
Convention Center.
ABSTRACT:
http://www.aapm.org/meetings/amos2/pdf/49-13212-37092-250.pdf
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