Table 1.

Conventional breast cancer prescreening/screening and emerging imaging modalities

	Modality	Physics	Application	Advantages	Disadvantages	Sensitivity	Specificity
Examinations	SBE	Self-physical examination for detecting breast lesions	Prescreening	Increases public awareness Can be used on high-risk populations Easy technique that can be performed at home	No effect on mortality of breast cancer30 High rates of false positives and overdiagnosis31	12%–14%32	–
	CBE	Clinical breast examination for detecting breast lesions	Prescreening	Reduced breast cancer mortality	No randomized controlled trails have been conducted of CBE in women not receiving other forms of screening30	57.14%34	97.11%34
				Can detect breast cancer missed by mammography (sometimes) May be effective in reducing mortality in women	Increased false-positive results32 Does not permit one to determine malignancy with assurance33 High rates of false positives and overdiagnosis31	40%–69%32	86%–99%32
Conventional imaging Emerging modalities	X-ray mammography (structural imaging)	High energy X-rays travel in a straight path and are attenuated by interaction with tissue	Screening (gold standard), diagnostic, prognostic	High specificity and sensitivity to detecting cancers Portable device	10% of false-positive cases Poor contrast compared to CT or MRI	68.6% (in 40–44 year olds) 83.3% (in 80–89 year olds)35	91.4%–94.4% (w/hormone replacement therapy)35
				Fast imaging time (approximately <1 minute) Good resolution (∼mm) More accuracy in dense breasts when using digital mammography	Uses ionizing radiation Less sensitive in radiographically dense breasts35
	Ultrasound (structural imaging)	Acoustic waves (mechanical) are introduced into the body and are reflected back toward a receiver	Screening, diagnostic, prognostic	High diagnostic utility among women with dense breasts30 Portable device Fast imaging time (approximately <1 minute) Nonionizing (safe)	High false-positive rates30 Poor contrast Poor resolution (∼cm)	Increases from 36% to 95% with Doppler36	Decreases from 86% to 79% with Doppler36
	CT (structural)	3D arrays of X-rays travel in a straight path and are attenuated by interaction with tissue	Screening, diagnostic, prognostic	Good resolution (∼mm) Poor contrast Fast imaging time (approximately <1 minute)	Non-portable device Expensive device	–	–
	MRI (structural)	RF signal is used to align water molecules to a changing magnetic field where the resultant RF signal is collected	Screening, diagnostic, prognostic	Sensitivity is nearly 100%12,37 Can better detect intraductal spread of cancer12	Specificity values vary12 and are poor37 MRI-guided biopsies are difficult and require compatible equipment12	88.1%38	67.7%38
				Good technique for post- chemotherapy imaging12 Excellent resolution (<mm) Nonionizing radiation	Only the lateral side of the breast is visible12 Not portable Slow imaging time (approximately over 20 minutes) Expensive device Good contrast
	PET (nuclear) – functional imaging	High-energy radioactive isotopes create two gamma rays that travel in opposite directions toward detectors	Screening, diagnostic, prognostic	Good contrast Functional information	Ionizing radiation Poor resolution (∼cm) Not portable Expensive device Slow imaging time (approximately over 20 minutes)	96%39	77%39
	Scintimammography – (functional imaging)	Uses nonspecific radionuclides to identify malignant lesions	Diagnostic	Good contrast Functional information	Ionizing radiation Not portable Slow imaging time High false positives40,41 Low sensitivity for small cancers (<1–1.5 cm) and ductal carcinoma in situ42	93%43	87%43
	Thermography (functional imaging)	Identifies vascular and temperature changes	Screening, diagnostic	Noninvasive Non-radiative Less imaging time Promise for dense breasts44	Easily affected by temperature Large breasts are poorly imaged High false positives and false negatives26	97%45	14%45
	Electrical impedance tomography (functional and structural)	Measures local dielectric properties of cancer cells, including electrical conductance and capacitance	Diagnostic, but works better for screening46	Noninvasive, non-radiative, and risk free Works well with dense breasts Relatively inexpensive46–48 Scans in approximately 15 minutes	High false-positive rates49 Poor spatial resolution than CT or MRI	72.2%50 38%46	67%50 95%46
	Microwave imaging (functional)	Employs microwave or millimeter waves to image dielectric bodies	Diagnostic	Noninvasive Non-radiative	Poor resolution at higher depth48 Low contrast in fibroglandular tissues	–	–
	Optical imaging (functional)	Employs near-infrared light (650–900 nm) to measure differences in absorption and scattering coefficients across different tissues	Screening, diagnostic, prognostic	Noninvasive Non-radiative Relatively inexpensive and portable Low imaging time (<1 minute) Good contrast (since functional information)	Highly scattered signal limits its depth imaging Limited spatial resolution when optical fibers are used	–	–

Abbreviations: SBE, self-breast examination; CBE, clinical breast examination; CT, computerized tomography; MRI, magnetic resonance imaging; PET, positron emission tomography; RF, radio frequency.