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In [[electronics]], the '''Gummel plot''' is the combined [[Mathematics|plot]] of the base and collector [[electric current]]s, <math>I_c</math> and <math>I_b</math>, of a [[Bipolar junction transistor|bipolar transistor]] vs. the base-emitter [[voltage]], <math>V_{be}</math>, on a semi-[[logarithmic scale]]. This plot is very useful in device characterization because it reflects on the quality of the emitter-base [[Junction (semiconductor)|junction]] while the base-collector bias, <math>V_{bc}</math>, is kept at a [[Constant (mathematics)|constant]].
Results of your large-scale clinical study presented with the annual meeting in the Radiological Society of North America ( RSNA 2009 ) provide the first strong evidence with the benefit of annual screening ultrasound for [http://En.Search.Wordpress.com/?q=females females] with dense breasts who will be [http://www.absolutemotors.sg/ used car export] at elevated risk for breast cancer. In addition, the research confirmed that MRI is especially sensitive in depicting early cancer of the breast.<br><br><br><br>


A number of other device parameters can be garnered either [[Quantitative property|quantitative]]ly or [[qualitative data|qualitative]]ly directly from the Gummel plot:<ref>A. S. Zoolfakar et N. A. Shahrol, « Modelling of NPN Bipolar Junction Transistor Characteristics Using Gummel Plot Technique », in 2010 International Conference on Intelligent Systems, Modelling and Simulation (ISMS), 2010, p. 396 ‑400</ref>
"We discovered that annual screening with ultrasound in addition to mammography significantly improves the detection of early cancer of the breast," said lead researcher Wendie A. Berg, M.D., Ph.D., breast imaging specialist at American Radiology Services, Johns Hopkins ' Green Spring Station in Lutherville, Md., "and that now more early breast cancer can be found when MRI is performed, despite combined screening with both ultrasound and mammography. However, both ultrasound and MRI improve the risk of false-positive findings."<br><br><br><br>Women who're at risky for cancer of the breast need to begin screening at a younger age, given that they often develop cancer prior to when women at average risk. However, women below age 50 are more likely to have dense breast tissue, which could limit the effectiveness of mammography being a screening tool.<br><br><br><br>Multicenter trials have demostrated that MRI enables radiologists to accurately identify tumors missed by mammography and ultrasound. The American Cancer [http://search.usa.gov/search?query=Society+recommends Society recommends] that some teams of women which has a high chance of developing cancer of the breast should be screened with MRI together with their yearly mammogram beginning at 30. However, MRI just isn't for everyone.<br><br><br><br>"Because MRI is an extremely expensive ensure that you requires intravenous contrast, it can be something we simply recommend for screening the approximately 2 percent of women who are known or likely carriers of BRCA1 or BRCA2 gene mutations or have other unusual circumstances that position them at very high risk for breast cancers," Dr. Berg said.<br><br><br><br>"There are another 10 or 15 percent of women who're at some increased risk because of personal history of breast cancers, genealogy of breast cancer and/or dense breast growth," she added. "For several of these women, MRI is not currently justified, but annual ultrasound would be appropriate along with mammography."<br><br><br><br>The researchers studied 612 women, mean age 55 years, at elevated risk of cancer of the breast enrolled at 14 sites within the American College of Radiology Imaging Network (ACRIN) 6666 trial funded by the Avon Foundation and also the National Cancer Institute. Women underwent baseline screening mammography and ultrasound with follow-up exams at 12 and 24 months and then an individual, contrast-enhanced MRI at a couple of years.<br><br><br><br>Sixteen women were diagnosed with breast cancer. Twelve with the cancers were invasive, and four were ductal carcinoma in situ (DCIS). Over the course in the study, 50 to 56 percent of cancers were shown on mammography. Adding ultrasound allowed detection of 70 to 94 percent of cancers. Adding MRI allowed for detection of additional cancers at their earliest stage.<br><br><br><br>The study also discovered that supplemental screening with ultrasound or MRI significantly increased the probability of false-positive findings, bringing about unnecessary biopsies in a few women.<br><br><br><br>"It is important that women are advised in the increased potential of undergoing an unnecessary biopsy as being a result of screening with ultrasound or MRI," Dr. Berg said, "but develop this study motivates females and their doctors to understand more about their risk factors also to consider supplemental screening as well as mammography where indicated."
* the common-emitter current gain, <math>\beta</math>, and the common-base current gain, <math>\alpha</math>
* base and collector ideality factors, <math>n</math>
* series [[electrical resistance|resistance]]s and [[leakage current]]s.
Sometimes the DC current gain, <math>\beta</math>, is plotted on the same figure as well.
 
[[File:SiGe HBT Gummel Plot.png|thumb|SiGe HBT Gummel Plot]]
 
==See also==
*[[Hermann Gummel]]
*[[Bipolar junction transistor]]
 
==References==
<references />
 
{{DEFAULTSORT:Gummel Plot}}
[[Category:Transistors]]
[[Category:Plots (graphics)]]
 
 
{{Electronics-stub}}

Latest revision as of 00:02, 6 January 2015

Results of your large-scale clinical study presented with the annual meeting in the Radiological Society of North America ( RSNA 2009 ) provide the first strong evidence with the benefit of annual screening ultrasound for females with dense breasts who will be used car export at elevated risk for breast cancer. In addition, the research confirmed that MRI is especially sensitive in depicting early cancer of the breast.



"We discovered that annual screening with ultrasound in addition to mammography significantly improves the detection of early cancer of the breast," said lead researcher Wendie A. Berg, M.D., Ph.D., breast imaging specialist at American Radiology Services, Johns Hopkins ' Green Spring Station in Lutherville, Md., "and that now more early breast cancer can be found when MRI is performed, despite combined screening with both ultrasound and mammography. However, both ultrasound and MRI improve the risk of false-positive findings."



Women who're at risky for cancer of the breast need to begin screening at a younger age, given that they often develop cancer prior to when women at average risk. However, women below age 50 are more likely to have dense breast tissue, which could limit the effectiveness of mammography being a screening tool.



Multicenter trials have demostrated that MRI enables radiologists to accurately identify tumors missed by mammography and ultrasound. The American Cancer Society recommends that some teams of women which has a high chance of developing cancer of the breast should be screened with MRI together with their yearly mammogram beginning at 30. However, MRI just isn't for everyone.



"Because MRI is an extremely expensive ensure that you requires intravenous contrast, it can be something we simply recommend for screening the approximately 2 percent of women who are known or likely carriers of BRCA1 or BRCA2 gene mutations or have other unusual circumstances that position them at very high risk for breast cancers," Dr. Berg said.



"There are another 10 or 15 percent of women who're at some increased risk because of personal history of breast cancers, genealogy of breast cancer and/or dense breast growth," she added. "For several of these women, MRI is not currently justified, but annual ultrasound would be appropriate along with mammography."



The researchers studied 612 women, mean age 55 years, at elevated risk of cancer of the breast enrolled at 14 sites within the American College of Radiology Imaging Network (ACRIN) 6666 trial funded by the Avon Foundation and also the National Cancer Institute. Women underwent baseline screening mammography and ultrasound with follow-up exams at 12 and 24 months and then an individual, contrast-enhanced MRI at a couple of years.



Sixteen women were diagnosed with breast cancer. Twelve with the cancers were invasive, and four were ductal carcinoma in situ (DCIS). Over the course in the study, 50 to 56 percent of cancers were shown on mammography. Adding ultrasound allowed detection of 70 to 94 percent of cancers. Adding MRI allowed for detection of additional cancers at their earliest stage.



The study also discovered that supplemental screening with ultrasound or MRI significantly increased the probability of false-positive findings, bringing about unnecessary biopsies in a few women.



"It is important that women are advised in the increased potential of undergoing an unnecessary biopsy as being a result of screening with ultrasound or MRI," Dr. Berg said, "but develop this study motivates females and their doctors to understand more about their risk factors also to consider supplemental screening as well as mammography where indicated."