Comparative study of handheld ultrasound ,automated breast volume scanner and breast specific gamma imaging in the diagnosis of breast cancer / 中华超声影像学杂志

Objective To compare the efficiencies of handheld ultrasound ,automated breast volume scanner ( ABVS) and breast specific gamma imaging (BSGI) in the diagnosis of breast cancer . Methods A retrospective review was performed in 200 women ( 210 breast lesions) underwent handheld ultrasound , ABVS and BSGI before surgery . The results were verified with histological examination . Results There was no obvious difference among the three methods in the sensitivity for the diagnosis of breast cancer( P >0 .05) . There was no difference of specificity between handheld ultrasound and ABVS ,BSGI( P = 0 .393 , 0 .139) . Compared with BSGI ,ABVS was an imaging modality with highest specificity for the diagnosis of breast cancer( P = 0 .021) ,and there was no difference between handheld ultrasound and ABVS ,BSGI ( P =0 .07 ,0 .29) . The areas under the ROC curve of handheld ultrasound ,ABVS and BSGI were 0 .855 ,0 .894 and 0 .818 ,respectively . The difference was obvious between ABVS and BSGI ( P = 0 .02) . Conclusions The diagnostic efficacy of ABVS in diagnosis of breast malignant lesions is similar to that of handheld ultrasound . BSGI has certain clinical value in the diagnosis of breast cancer ,and it is an effective supplement for breast cancer ultrasound examination .

Analytic simulator and image generator of multiple-scattering Compton camera for prompt gamma ray imaging

For prompt gamma ray imaging for biomedical applications and environmental radiation monitoring, we propose herein a multiple-scattering Compton camera (MSCC). MSCC consists of three or more semiconductor layers with good energy resolution, and has potential for simultaneous detection and differentiation of multiple radio-isotopes based on the measured energies, as well as three-dimensional (3D) imaging of the radio-isotope distribution. In this study, we developed an analytic simulator and a 3D image generator for a MSCC, including the physical models of the radiation source emission and detection processes that can be utilized for geometry and performance prediction prior to the construction of a real system. The analytic simulator for a MSCC records coincidence detections of successive interactions in multiple detector layers. In the successive interaction processes, the emission direction of the incident gamma ray, the scattering angle, and the changed traveling path after the Compton scattering interaction in each detector, were determined by a conical surface uniform random number generator (RNG), and by a Klein-Nishina RNG. The 3D image generator has two functions: the recovery of the initial source energy spectrum and the 3D spatial distribution of the source. We evaluated the analytic simulator and image generator with two different energetic point radiation sources (Cs-137 and Co-60) and with an MSCC comprising three detector layers. The recovered initial energies of the incident radiations were well differentiated from the generated MSCC events. Correspondingly, we could obtain a multi-tracer image that combined the two differentiated images. The developed analytic simulator in this study emulated the randomness of the detection process of a multiple-scattering Compton camera, including the inherent degradation factors of the detectors, such as the limited spatial and energy resolutions. The Doppler-broadening effect owing to the momentum distribution of electrons in Compton scattering was not considered in the detection process because most interested isotopes for biomedical and environmental applications have high energies that are less sensitive to Doppler broadening. The analytic simulator and image generator for MSCC can be utilized to determine the optimal geometrical parameters, such as the distances between detectors and detector size, thus affecting the imaging performance of the Compton camera prior to the development of a real system.

FPGA-Based Interface of Digital DAQ System for Double-Scattering Compton Camera / 대한핵의학회잡지

PURPOSE: The double-scattering Compton camera (DSCC) is a radiation imaging system that can provide both unknown source energy spectra and 3D spatial source distributions. The energies and detection locations measured in coincidence with three CdZnTe (CZT) detectors contribute to reconstructing emission energies and a spatial image based on conical surface integrals. In this study, we developed a digital data acquisition (DAQ) board to support our research into coincidence detection in the DSCC.METHODS: The main components of the digital DAQ board were 12 ADCs and one field programmable gate array (FPGA). The ADCs digitized the analog 96-channel CZTsignals at a sampling rate of 50MHz and transferred the serialized ADC samples and the bit and frame clocks to the FPGA. In order to correctly capture the ADC sample bits in the FPGA, we conducted individual sync calibrations for all the ADC channels to align the bit and frame clocks to the right positions of the ADC sample bits. The FPGA logic design was composed of IDELAYand IDDR components, six shift registers, and bit slip buffer resources.RESULTS: Using a Deskew test pattern, the delay value of the IDELAY component was determined to align the bit clock to the center of each sample bit.We determined the bit slip in the 12-bit ADC sample using an MSB test pattern by checking where the MSB value of one is located in the captured parallel data.CONCLUSION: After sync calibration, we tested the interface between the ADCs and the FPGA with a synthetic analog Gaussian signal. The 96 ADC channels yielded a mean R2 goodness-of-fit value of 0.95 between the Gaussian curve and the captured 12-bit parallel data.

Validity of breast-specific gamma imaging for Breast Imaging Reporting and Data System 4 lesions on mammography and/or ultrasound

PURPOSE: The purpose of this study was to assess the breast-specific gamma imaging (BSGI) in Breast Imaging Reporting and Data System (BI-RADS) 4 lesions on mammography and/or ultrasound. METHODS: We performed a retrospective review of 162 patients who underwent BSGI in BI-RADS 4 lesions on mammography and/or ultrasound. RESULTS: Of the 162 breast lesions, 66 were malignant tumors and 96 were benign tumors. Sensitivity and specificity of BSGI were 90.9% and 78.1%, and positive predictive value and negative predictive value were 74.1% and 92.6%. The sensitivity or specificity of mammography and ultrasound were 74.2% and 56.3% and 87.9% and 19.8%, respectively. The sensitivity and specificity of BSGI for breast lesions ≤1 cm were 88.0% and 86.8%, while the values of beast lesions >1 cm were 92.7% and 61.5%. The sensitivity or specificity of BSGI and mammography for patients with dense breasts were 92.0% and 81.3% and 72.0% and 50.0%, respectively. 26 patients showed neither a nodule nor microcalcification on ultrasound, but showed suspicious calcification on mammography. The sensitivity and specificity of BSGI with microcalcification only lesion were 75.0% and 94.4%. CONCLUSION: This study demonstrated that BSGI had shown high sensitivity and specificity, as well as positive and negative predictive values in BI-RADS 4 lesions on ultrasound and/or mammography. BSGI showed excellent results in dense breasts, in lesions that are less than 1 cm in size and lesions with suspicious microcalcification only.

Diagnostic accuracy of breast specific gamma imaging in the detection of breast cancer in high risk women: A meta-analysis

Mammography remains the mainstay of screening for primary breast cancer, however, some limitations persists in women with dense breast, in its inability to differentiate a benign from a malignant lesion, and in its heavy reliance on the radiologists' skill. Breast specific gamma imaging, which evaluates the functional images rather than anatomic images seen in mammography, addresses these limitations and can be a potential adjunct in screening for breast cancer. This meta-analysis aims to determine the diagnostic accuracy of breast specific gamma imaging for diagnosing breast cancer in women who are high risk. We searched PUBMED (1999-2009) and Google Scholar (1999-2009) for diagnostic accuracy studies that compared breast specific gamma imaging with histopathologic diagnosis of breast cancer in high risk women. Citation searches and screening of references of included studies were conducted. Two authors searched citations that correlated with the criteria using a data collection form. The methodological quality was then assessed by three authors using the QUADAS method. HSROC meta-analytical tool was used to estimate summary ROC curves. Four studies with 360 participants and 411 lesions were included. Breast specific gamma imaging has a high sensitivity (84%-97%) and specificity (60%-86%). SROC shows the included studies have high overall accuracy. Breast specific gamma imaging has high diagnostic accuracy in detecting breast cancer in women at high risk.