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Q: position medio-lateral-oblique mammograms ( Answered 4 out of 5 stars,   2 Comments )
Subject: position medio-lateral-oblique mammograms
Category: Health > Medicine
Asked by: dave222smith-ga
List Price: $200.00
Posted: 03 Nov 2002 07:19 PST
Expires: 03 Dec 2002 07:19 PST
Question ID: 97274
can you give a detailed comparison between the use of Parallel and
Tangent methods in position medio-lateral-oblique mammograms. The
comparsion shall be from economical, quality, requirements,
technological..,etc points of view. which is more difficult to
perform? will Tangent method find a greater favour in the near future?

Clarification of Question by dave222smith-ga on 04 Nov 2002 01:59 PST
My question was about diagnosing BREAST CANCER..which method (parallel
or Tangent) of medio-lateral-oblique mammograms diagnoses better?
which method is currently most commonly used? and why? include merits
of the tangent method(e.g.less radiation may be?)? which method is
more expensive? and requires more work from the RADIOGRAPHER

Request for Question Clarification by bcguide-ga on 04 Nov 2002 22:33 PST

I'm stumped. I can find plenty of information on these terms for
radiotherapy, but not a reference for mammography. Is there any other
terminology that might produce better results? I have calls in to a
couple of mammography centers, but they're pretty busy. Where did you
get these specific terms? Some additional information might reveal a
lead to follow in this search. I'll keep trying in the meantime.


Clarification of Question by dave222smith-ga on 05 Nov 2002 09:05 PST
Thanks for your question.
I am not interested in radiotherapy. This research is solely linked to
radiography. It seems to be that there are two methods (parallel and
tangent) used to ASSESS THE QUALITY of the medio-lateral-obilque
mammograms (which is used to diagnose breast cancer). From my humble
knoweledge, i can tell you that, for the first method of assessment,
the pictural muscle should be in one line and parallel to the film. In
the second method, we take an angle of 90 deg. to the tangent of the
breast and the point of the nipple.
A comparison between the two assessment techniques is what i am
looking for. Which method gives better results? which is quicker?
cheaper? easier to perform? on what basis should the radiogerapher use
either methods when dealing with symptomatic and treated females.
You might find this web site helpful: Pub/PhDThesis/PhD_Chapter5.pdf
You are welcome to ask any time.

Request for Question Clarification by tomo-ga on 15 Nov 2002 05:47 PST
Hello again, dave222smith,

Are you sure about your terminology?  Where did you hear about these
methods?  There are a number of positions that are a part of
diagnostic BC mammography, which could be called "parallel" and
"tangent", but they are not in conjunction with MLO.

I'll keep looking, but a pointer to where you got this from would be

-- tomo-ga

Request for Question Clarification by tomo-ga on 15 Nov 2002 06:06 PST
Duh, I just read your previous clarification and it answered my question.

Request for Question Clarification by tomo-ga on 15 Nov 2002 07:18 PST

As much as I would like to answer your question, I have to renew my
previous clarification request or, at least, restate it.

As far as I can tell, "tangent" and "parallel" do not apply to MLO
mammograms, but rather, are in addition to MLO.  In a nutshell, the
goal with mammography is to image as much of the breast as possible
with as few doses as possible.  This is especially true of "screening"
tests, where the woman does not have any symptoms and the mammogram is
just routine.  Notwithstanding that, different views exist to help
detect (hopefully) small anomolies in a three-dimensional object on a
two-dimensional medium.  There is no one right view, or another vying
for favour.

In the paper you point to, the discussion is principally around the
indentification of control points ("registration") on a mammogram to
facilitate the subsequent post-processing of a series of images,
presumably by computer.  While they talk about the various positions
for mammograms, and the compression directions required for them,
there is nothing to suggest that "tangent" and "parallel" are clinical
methods seeking favour.

So, I can post a good discussion of mammography techniques, equipment,
and future trends, but that is not what you are asking for.  But I
don't want to post an answer saying "I think you might have your
terminology a bit mixed up", and stop there and take your $200.

Oh, and I genuinely hope that you are asking merely out of interest
and not because you need to know, if you get my drift.  If you do
*need* to know, I feel for you in a "been there done that" way.

Let me know what you would like.

-- tomo-ga

Request for Question Clarification by aceresearcher-ga on 16 Nov 2002 22:27 PST

"Parallel" and "Tangent" are not two methods used to assess the
quality of a mammogram. They are two angles at which the x-ray film
shots are taken.

Will you consider a description and comparison of the various methods
which ARE used to assess the accuracy and efficacy of mammogram films
after they are taken an acceptable answer, even if the answer does not
include "parallel" and "tangent"?



Clarification of Question by dave222smith-ga on 17 Nov 2002 08:24 PST
I do apologize for the mis-understanding when i first posted my
I don't want you to talk about Parallel and Tangentangles at which the
x-ray film shots are taken. YES, I will happily accept a description
and comparison of the various methods which ARE used to assess the
accuracy and efficacy of mammogram films after they are taken, BUT
shouldn't they include "parallel" and "tangent"? Before posting your
answer please consider reading the following web sites i just got hold

I havn't read them yet but don't they suggest Parallel and Tangent
methods to check whether the mammogram was alright or not? breast was
included or not?

Request for Question Clarification by aceresearcher-ga on 17 Nov 2002 10:39 PST

The first 2 articles are descriptions of the angles at which to
position the breasts in order to get good, diagnostic images, not
descriptions of methods used for evaluating those images.

I got a "Page Not Found" message for the 3rd link.


Clarification of Question by dave222smith-ga on 18 Nov 2002 05:49 PST
I agree with your last clarification! you can post your answer
and comparing the various methods which ARE used to assess the
accuracy and efficacy of BREAST mammogram films after they are
taken..I will continue my search about the parallel and tangent and I
will keep you updated.

Request for Question Clarification by aceresearcher-ga on 19 Nov 2002 19:53 PST

Thanks for your invitation! After doing some work on this, because it
appears the medical community has arrived at some agreement in the
techiques for taking and evaluating mammograms, it looks like what I
can give you is:

1) a detailed explanation of the various things radiologists look for
when they evaluate mammograms;
2) a detailed explanation of the various diagnostic techniques
(including mammograms) which are used to detect breast cancer.

Would you consider these things an acceptable Answer?



Clarification of Question by dave222smith-ga on 20 Nov 2002 11:59 PST
YES I will accept that as an answer BUT, please, try to focus more on
explaning the various things radiologists look for when evaluating MLO
breat mammograms..and try to include inline references when writing
your answer, so I can refer to them in the future..wishing you best of
luck aceresearcher


Request for Question Clarification by aceresearcher-ga on 20 Nov 2002 13:01 PST
That helps a lot in giving me direction. Please bear with me a couple
of days. I am going to pull together just as much information as I
can, and I want to give you a quality answer, rather than just a list of

Clarification of Question by dave222smith-ga on 20 Nov 2002 16:39 PST
I checked your previous answers and your record and I know that you
will give a first class answer! Take your time and Thank you!
Subject: Re: position medio-lateral-oblique mammograms
Answered By: legolas-ga on 20 Nov 2002 22:14 PST
Rated:4 out of 5 stars
Hi dave222smith, 

I'm glad you were able to clarify your question. I did a lot of
searching based on your original question, but was unable to proceed
until you clarified.

I found a site called Aunt Minnie ( ) which
focuses on Radiology. Using the search terms, "assess quality
mammogram", I found an article which describes some of the techniques
used to evaluate mammograms and detect possible cancerous lesions.

Missed breast cancer: Avoiding this pitfall
By: Ellen Shaw de Parides, MD
Republished with permission from Applied Radiology - October 2000 

To summarize, if there are dense spots found on the MLO view (which
may, but not always, indicate a cancer), a mediolateral view and an
exagerated or rolled craniocaudal (CC) view should used also.

The radiologist should compare mirror images side by side (CC and MLO)
to avoid missing lesions. If a lesion is found on one view, the
radiologist should search the other view in the same arc (measured
from the nipple). The retroglandular area in the posterior of the
breast should not be missed, as sometimes occurs with non-experienced

Multiple views should be made before making a decision about where the
lesion is located. Ultrasound is useful in evaluating posteriorly
located masses that have only been seen on one view.

Also at , I used the term "MLO" and found
the following article on evaluating clinical images of conventional
screen-film mammography.

Poor breast positioning thwarts mammo accreditation
By: Tracie L. Thompson
In 1997,  the American College of Radiology developed the Mammography
Accreditation Program. ACR-MAP reviewed images from 2,341 mammography
units in that year, 1,034 (44%) of which failed their initial
evaluation. The ACR-MAP looks at eight categories when evaluating
clinical radiology images: positioning,  exposure, contrast,
compression, sharpness, noise, labeling and artifacts. They found that
positioning was the area where clinics where failing to meet
standards, followed by exposure, compression, sharpness and contrast.
The most commonly cited problem was an inadequate amount of pectoral
muscle on MLO views.

I also searched PubMed (
), using the terms "assess quality MLO" and found the following

Screening mammography: clinical image quality and the risk of interval
breast cancer.
Taplin SH, Rutter CM, Finder C, Mandelson MT, Houn F, White E. 
AJR Am J Roentgenol 2002 Apr;178(4):797-803

This study evaluated the association between the quality of clinical
images and breast cancer occuring within 24 months after a negative
mammogram.  They used the Breast Imaging Reporting and Data System
(BI-RADS) data to determine if cancers had been present or absent at
the original screening. The researchers found that cancer detection
was the highest among patients who had proper breast positioning at
their initial screening. Detecting a cancer after an interval where
the patient was initially given a negative prognosis was more likely
after images failed for positioning. The researchers conclude that
invasive cancer detection may be improved by improving the breast
positioning during screening.

On the issue of compression and image quality, I found the following
Breast biphasic compression results in better image quality and a
greater amount of breast tissue than monophasic compression for both
CC and MLO views.

In further searching, I found that one technique that is being
researched is the use of computerized analysis to read both CC and MLO
mammograms. The following abstract describes a study using the
computerized method:

IEEE Trans Med Imaging 2001 Dec;20(12):1285-92 
Computerized analysis of multiple-mammographic views: potential
usefulness of special view mammograms in computer-aided diagnosis.
Huo Z, Giger ML, Vyborny CJ.
Department of Radiology, The University of Chicago, IL 60637, USA.

The researchers investigated the usefulness of special view mammograms
(spot compression or spot compression magnification) when computer
aided diagnosis was done of mammographic breast lesions.

 Analysis using the computer program found that by only using the
special views, 58% of the cases could be correctly diagnosed. Use of
the CC and MLO views alone correctly classified 12% and 24%,
respectively of the cases.

I've copied a short blub from an article

"...Some of the issues being addressed in mammography quality
assurance are 1) that image quality is the most important technical
aspect of mammography; 2) that image quality has improved steadily
over the past two decades and will continue to improve at most
mammography sites in the United States; 3) that the American College
of Radiology's Mammography Accreditation Program is the best way to
ensure high quality mammogram; 4) that access to high quality
mammography is not geographically restricted, with over half the
mammography sites in the United States now ACR accredited and another
30% participating in the accreditation process; 5) that regular and
effective quality assurance, as described in the ACR Mammography
Quality Control Manuals and as required of ACR accredited sites, is
the only way to ensure that superior mammography image quality is
maintained; and 6) that sites with higher mammography volume have
better quality assurance practices and lower failure rates than others
within the ACR Mammography Accreditation Program..."

Other methods that can be used to detect breast cancer include
scintimammography and ultrasound. The abstract for article on
scintimammography can be found at:

Three-dimensional ultrasound can be used to show the margins and
topography of breast lesions, aiding in determining if they are benign
or malignant. If biopsy is required, 3D ultrasounds can help with
needle localization and guidance.

In my search, digital mammography appears to be one of the latest
innovations in improving the quality of image available from

Full field digital mammography creates better image quality than
conventional screen-film mammography systems.

Digital mammography and associated mathematical algorithms can aid in
improving the quality of screening and detection of lesions.

An algorithm has been created to correct for varying densities of
breast tissue. You can find the article at:

Other sites of interest:
From AuntMinnie, I found a list of research journal on radiography,
which led me to the Radiological Society of North America.

You can search their two journals, Radiology and Radiographics at: 

I hope this gives you the information you wanted. Should any part of
this answer be unclear, please ask for clarification prior to rating.

Request for Answer Clarification by dave222smith-ga on 22 Nov 2002 14:01 PST

Thanks for your answer. Most of information given are relevant but, I
must admit, I was hoping for a more detailed answer for this high
price. Could you just explain the following two articles a little bit
more and find some more similar articles talking about exactly the
same two subjects addressed, because they seem to be the most valuable
ones for my research:

1) Poor breast positioning thwarts mammo accreditation .By: Ellen Shaw
de Parides, MD
(That contains description of the techniques used to evaluate
mammograms and detect possible cancerous lesions)

2) Screening mammography: clinical image quality and the risk of
breast cancer.
Taplin SH, Rutter CM, Finder C, Mandelson MT, Houn F, White E.  
AJR Am J Roentgenol 2002 Apr;178(4):797-803 

Thank you once again.

Clarification of Answer by legolas-ga on 22 Nov 2002 14:07 PST
I will provide you with the information requested shortly.

Thanks again!

Clarification of Answer by legolas-ga on 22 Nov 2002 16:59 PST
Hi dave222smith,

I did not initially notice that your request for clarification was
directed at aceresearcher - and not to me (Legolas-ga). I was the
researcher who answered the question for you (not aceresearcher).

I am still working on getting some more information for you as
requested, and ask for a little more time to prepare the clarification
to give you the best information I can.

I should have more information for you later tonight (Nov 22, 2002).

Thanks so much for your patience!

Clarification of Answer by legolas-ga on 22 Nov 2002 18:46 PST
Hi dave222smith,

I'd like to ensure, prior to posting my clarification, that you are
indeed happy with me answering your question as opposed to
Aceresearcher. Upon re-reading your back-and-forth banter with
Aceresearcher, it has become unclear to me as to whether or not you
implied that you *only* wanted Aceresearcher to answer your question,
or if you were happy with any researcher--as long as you got the
information you were looking for.

I will await your clarification prior to posting the clarification. I
can assure you however that I will work with you until you are
satisfied with the information I have provided to you: but, if you
prefer aceresearcher to answer your question, I will withdraw my
answer and allow her to give you an answer herself. That means that my
answer will no longer appear on this site, nor will I receive any
compensation for the answer: however, I want to make sure that you are
happy with the answer you receive!

I can tell you that I was able to find other studies that discuss
breast positioning with MRI's (related to your clarification about
'registration points' of the breast), however I can tell you that this
is the first and only study ("Screening mammography: clinical image
quality and the risk of interval
breast cancer" - published in April 2002) which actually looks at the
correlation between breast lesions missed and the position of the
patient during the test.

I have been able to find a link to a press release for the study,
which gives a short description if you'd rather read that then order
the study online.



Request for Answer Clarification by dave222smith-ga on 22 Nov 2002 21:56 PST
aceresearcher-ga and legolas-ga,
I am sorry but the question was directed to aceresearcher-ga, I
thought she was the one who gave me the answer. So sorry Legolas! I
think it is unfair to accept an answer from you since she was locking
the question and I was given a word from her to get an answer within 2
days, I do apologize for you, and I promise that my next question will
be directed to you!

Clarification of Answer by legolas-ga on 23 Nov 2002 11:08 PST
I am posting this clarification as requested: however, I have also
asked Google how to proceed in this matter. I do not want to put you
in a position where you have to wait for your answer due to reasons
which are not your fault.

The first article, "Poor breast positioning thwarts mammo
accreditation" can be found at:
However, you will have to register (free registration) to view the
page. There is unfortunately not much more information on the site
than what I have already summarized for you.

However, I did some further searching and was able to find the
original research article. The full journal citation is:

Reasons for Failure of a Mammography Unit at Clinical Image Review in
the American College of Radiology Mammography Accreditation Program1
Lawrence W. Bassett, MD, Dione M. Farria, MD, MPH, Swati Bansal, MS,
Marybeth A. Farquhar, RN, MSN, Pamela A. Wilcox, MBA and Stephen A.
Feig, MD
(Radiology. 2000;215:698-702.)

The full text of the article is available at:

The purpose of this study was to identify the most common problems in
mammogram quality submitted for clinical image evaluation. Mammography
clinics submitted images from actual patient referred for mammography
as part of their accreditation process with the American College of
Radiology Mammography Accreditation Program.  Twenty percent of the
reasons for failing the process were due to poor image quality related
to improper positioning.  A higher proportion of failures were found
for fatty breasts than for dense breasts.

In the article, the researchers found nine issues with positioning
that resulted in poor image quality.

-Inadequate pectoralis major muscle on MLO view 733 cases (22%) 
-Sagging of the breast on MLO view 462 cases (14%) 
-Poor visualization of posterior tissue on MLO view 459 cases (14%)
-Skin folds overlying breast tissue 410 cases (12%) 
-Poor visualization of posterior tissue on CC view 380 cases (11%) 
-Posterior nipple line on CC view not within 1 cm of that on MLO view
335 (10%)
-Excessive lateral or medial exaggeration on CC view 188 (6%)
-Breast positioned too high on image receptor 126 (4%)
-Portion of breast cut off 99 cases (3%) 
-Other 208 cases (6%)   
Total 3,400 cases (100%)

The second article, "Screening mammography: clinical image quality and
the risk of interval breast cancer." can be found at:
However, to view the whole article online requires a fee of $10 to be
paid which will allow you access to the article for 24 hours from the
computer you are using when you pay the fee.

I?ve found a press release on the study above. The press release can
be found at:

In the press release, they indicated that the study above showed a
correlation between a woman?s position during a mammogram and the
number of cancers missed. The proper position shows the muscle behind
the breast, the entire breast, and the nipple on the mammogram. This
can be accomplished if the patient leans over more during the
procedure. The author contends that prior to this study proper
criterion for accurate positioning was not available to technologists.

The study itself is published in the American Journal of
Roentgenology. The full citation is

Screening Mammography: Clinical Image Quality and the Risk of Interval
Breast Cancer
Stephen H. Taplin, Carolyn M. Rutter, Charles Finder, Margaret T.
Mandelson, Florence Houn, and Emily White
AJR 2002;178:797-803 

Earlier, you had referenced a dissertation which examined
?registration? points in the breast. I was able to find an article
which deal with position/breast movement during procedures. I was
unable to find reference to mammograms specifically, but perhaps these
two will give you additional information that will be useful in your

The first article deals with breast positioning during magnetic
resonance imaging. They found that breast tissue movement in larger
breasts can accommodated by immobilization through a breast cast.
Smaller breasts did not have a significant about of movement. The full
citation is:

Med Phys 2002 Sep;29(9):2062-9	

Reproducibility of mammary gland structure during repeat setups in a
supine position.

Klein Zeggelink WF, Deurloo EE, Muller SH, Schultze Kool LJ, Gilhuijs

Again, I have contacted Google Answers Editors with a question of how
to proceed--but, since you are not inconvenienced by this, I am
providing you with more information now.

Apart from this mixup, I certainly hope that I have given you the
information you need in an understandable, clear and informative way.

Sorry about the mixup,


Clarification of Answer by legolas-ga on 25 Nov 2002 21:11 PST
Thanks so much for your patience with this question. I really do hope
I was able to provide you with useful information.

Thanks again!

dave222smith-ga rated this answer:4 out of 5 stars
Thanks for your answer I do appreciate your hard work

Subject: Re: position medio-lateral-oblique mammograms
From: tomo-ga on 17 Nov 2002 15:08 PST
Sorry, Dave, but every reference you have suggested points to
different views for the mammogram image, and not anything about
assessment of the image for its "accuracy and efficacy".

I'm really confused, and disappointed that I couldn't help you out.

-- tomo-ga
Subject: Re: position medio-lateral-oblique mammograms
From: aceresearcher-ga on 22 Nov 2002 15:04 PST

I'm sorry, but legolas-ga is the one who answered your question. You
will need to address your Requests for Clarification to him.


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