Diagnostic performance of mammography and ultrasound in breast cancer: a systematic review and meta-analysis.

PURPOSE: The purpose of this study was to assess the diagnostic performance of mammography (MMG) and ultrasound (US) imaging for detecting breast cancer. METHODS: Comprehensive searches of PubMed, Scopus and EMBASE from 2008 to 2021 were performed. A summary receiver operating characteristic curve (SROC) was constructed to summarize the overall test performance of MMG and US. Histopathologic analysis and/or close clinical and imaging follow-up for at least 6 months were used as golden reference. RESULTS: Analysis of the studies revealed that the overall validity estimates of MMG and US in detecting breast cancer were as follows: pooled sensitivity per-patient were 0.82 (95% CI 0.76-0.87) and 0.83 (95% CI 0.71-0.91) respectively, The pooled specificities for detection of breast cancer using MMG, and US were 0.84 (95% CI 0.73-0.92) and 0.84 (95% CI 0.74-0.91) respectively. AUC of MMG, and US were 0.8933 and 0.8310 respectively. Pooled sensitivity and specificity per-lesion was 76% (95% CI 0.62-0.86) and 82% (95% CI 0.66-0.91) for MMG and 94% (95% CI 0.87-0.97) and 84% (95% CI 0.74-0.91) for US. CONCLUSIONS: The meta-analysis found that, US and MMG has similar diagnostic performance in detecting breast cancer on per-patient basis after corrected threshold effect. However, on a per-lesion basis US was found to have a better diagnostic accuracy than MMG.

Gold-nanoparticle-enriched breast tissue in breast cancer treatment using the INTRABEAM® system: a Monte Carlo study.

Using a 50-kV INTRABEAM® system after breast-conserving surgery, breast skin injury and long treatment time remain the challenging problems when large-size spherical applicators are used. This study has aimed to address these problems using gold (Au) nanoparticles (NPs). For this, surface and isotropic doses were measured using a Gafchromic EBT3 film and a water phantom. The particle propagation code EGSnrc/Epp was used to score the corresponding doses using a geometry similar to that used in the measurements. The simulation was validated using a gamma index of 2%/2 mm acceptance criterion in the gamma analysis. After validation Au-NP-enriched breast tissue was simulated to quantify any breast skin dose reduction and shortening of treatment time. It turned out that the gamma value deduced for validation of the simulation was in an acceptable range (i.e., less than one). For 20 mg-Au/g-breast tissue, the calculated Dose Enhancement Ratio (DER) of the breast skin was 0.412 and 0.414 using applicators with diameters of 1.5 cm and 5 cm, respectively. The corresponding treatment times were shortened by 72.22% and 72.30% at 20 mg-Au/g-breast tissue concentration, respectively. It is concluded that Au-NP-enriched breast tissue shows significant advantages, such as reducing the radiation dose received by the breast skin as well as shortening the treatment time. Additionally, the DERs were not significantly dependent on the size of the applicators.

Dosimetric effect of nanoparticles in the breast cancer treatment using INTRABEAM®system with spherical applicators in the presence of tissue heterogeneities: A Monte Carlo study.

Using the 50 kV INTRABEAM®IORT system after breast-conserving surgery: tumor recurrence and organs at risk (OARs), such as the lung and heart, long-term complications remain the challenging problems for breast cancer patients. So, the objective of this study was to address these two problems with the help of high atomic number nanoparticles (NPs). A Monte Carlo (MC) Simulation type EGSnrc C++ class library (egspp) with its Easy particle propagation (Epp) user code was used. The simulation was validated against the measured depth dose data found in our previous study (Tegaw,et al2020 Dosimetric characteristics of the INTRABEAM®system with spherical applicators in the presence of air gaps and tissue heterogeneities,Radiat. Environ. Biophys. (10.1007/s00411-020-00835-0)) using the gamma index and passed 2%/2 mm acceptance criteria in the gamma analysis. Gold (Au) NPs were selected after comparing Dose Enhancement Ratios (DERs) of bismuth (Bi), Au, and platinum (Pt) NPs which were calculated from the simulated results. As a result, 0.02, 0.2, 2, 10, and 20 mg-Au/g-breast tissue were used throughout this study. These particles were not distributed in discrete but in a uniform concentration. For 20 mg-Au/g-breast tissue, the DERs were 3.6, 0.420, and 0.323 for breast tissue, lung, heart, respectively, using the 1.5 cm-diameter applicator (AP) and 3.61, 0.428, and 0.335 forbreast tissue, lung, and heart using the 5 cm-diameter applicator, respectively. DER increased with the decrease in the depth of tissues and increase in the effective atomic number (Zeff) and concentration of Au NPs, however, there was no significant change as AP sizes increased. Therefore, Au NPs showed dual advantages such as dose enhancement within the tumor bed and reduction in the OARs (heart and lung).

Dosimetric characteristics of the INTRABEAM ® system with spherical applicators in the presence of air gaps and tissue heterogeneities.

The main aim of this study was to investigate the dosimetric characteristics of the INTRABEAM ® system in the presence of air gaps between the surface of applicators (APs) and tumor bed. Additionally, the effect of tissue heterogeneities was another focus. Investigating the dosimetric characteristics of the INTRABEAM® system is essential to deliver the required dose to the tumor bed correctly and reduce the delivered dose to the ribs and lung. Choosing the correct AP size and fitting it to the lumpectomy cavity is essential to remove the effect of air gaps and avoid inaccurate dose delivery. Consequently, the Geant4 toolkit was used to simulate the INTRABEAM ® system with spherical APs of various sizes. The wall effect of the ion chamber (IC) PTW 34013 used in the present study was checked. The simulations were validated in comparison with measurements, and then used to calculate any inaccuracies in dose delivery in the presence of 4- and 10-mm air gaps between the surface of the APs and the tumor bed. Also, the doses received due to tissue heterogeneities were characterized. It turned out that measurements and simulations were approximately in agreement (± 2%) for all sizes of APs. The perturbation factor introduced by the IC due to differences in graphite-coated polyethylene and air as compared to the phantom material was approximately equal to one for all AP. The greatest relative dose delivery difference was observed for an AP with a diameter of 1.5 cm, i.e., 44% and 70% in the presence of 4- and 10-mm air gaps, respectively. In contrast, the lowest relative dose delivery difference was observed for an AP with a diameter of 5 cm, i.e., 24% and 42% in the presence of 4- and 10-mm air gaps, respectively. Increasing APs size showed a decrease in relative dose delivery difference due to the presence of air gaps. In addition, the undesired dose received by the ribs turned out to be higher when a treatment site closer to the ribs was assumed. The undesired dose received by the ribs increased as the AP size increased. The lung dose turned out to be decreased due to the shielding effect of the ribs, small lung density, and long separation distance from the AP surface.

Techniques for generating attenuation map using cardiac SPECT emission data only: a systematic review.

To reliably interpret and perform quantitative analysis, attenuation correction for cardiac single-photon emission computed tomography (SPECT) is fundamental. Thus, knowledge of the patient-specific attenuation map for accurate correction is required in SPECT quantitative imaging. The aim of this systematic review is to present general principles of attenuation correction and provide a structured summary of the approaches that have been proposed for generating the attenuation map for cardiac SPECT. We identified relevant articles published in English pertaining to the attenuation map (AM) determination using SPECT emission data only by searching PubMed, EMBASE, Scopus, and Web of Science databases. Moreover, other articles were hand searched. The protocol of this systematic review was registered in PROSPERO and the code given is CRD42017060512. Transmissionless techniques of determining attenuation map including calculated methods, statistical modeling for simultaneous estimation of attenuation and emission, consistency conditions criteria, using scattered data and other methods were reviewed. Methods for performing attenuation map for cardiac SPECT are developing and the progresses made are promising. However, much work is needed to assess the efficacy of the correction schemes in the clinical routine.