Dynamic X-ray elastography using a pulsed photocathode source

X-ray absorption of breast cancers and surrounding healthy tissue can be very similar, a situation that sometimes leads to missed cancers or false-positive diagnoses. To increase the accuracy of mammography and breast tomosynthesis, we describe dynamic X-ray elastography using a novel pulsed X-ray source. This new imaging modality provides both absorption and mechanical properties of the imaged material. We use a small acoustic speaker to vibrate the sample while a synchronously pulsed cold cathode X-ray source images the mechanical deformation. Using these stroboscopic images, we derive two-dimensional stiffness maps of the sample in addition to the conventional X-ray image. In a breast phantom composed of ZrO2 powder embedded in gel, dynamic elastography derived stiffness maps were able to discriminate a hard inclusion from surrounding material with a contrast-to-noise ratio (CNR) of 4.5. The CNR on the corresponding absorption image was 1.1. This demonstrates the feasibility of dynamic X-ray elastography with a synchronously pulsed X-ray source.

Role of GNPS on the Enhancement of Proton Therapy of Breast Tumor Using MCNPX Simulation

Background: The beam therapy plays an important role in the treatment of cancer, which is the most common and successful form of treatment used after surgery. In proton therapy, proton beam (PB) particles irradiate the tumor. To enhance the treatment of breast tumor it is possible to inject gold nanoparticles (GNPS) into the tumor at the same time as irradiating the PB. The aim of this paper is the simulation of the treatment of breast tumors by using PBs and injecting GNPS with different concentrations, simultaneously. Therefore, we introduce the breast phantom (BP), then we irradiate it with a proton pencil beam, which is also injected with GNPS at the same time. In order to show the enhancement of the absorbed dose in the tumor, we use MCNPX.2.6 code. Results: The findings of our simulations show that the location of the Bragg's peak within the tumor shifts to higher depths with increasing energy. Also, by injecting GNPS in different amounts of 10, 25, 50 and 75 mg / ml with simultaneously irradiation of the PB, the rate of absorbed dose increases up to 1.75% compared to the non-injected state. Our results also show that the optimal range of proton energy that creates Bragg peaks within the tumor is between 52 to 65 MeV, which causes the creation of spread out of Bragg peak. It should be noted that the amount of absorbed dose is affected by quantities such as total stopping power, average Coulomb scattering angle, CSDA range and straggling range. Conclusion: This work offers new insights based on the use of GNPS in the treatment of breast cancer through proton therapy and indicates that the addition of GNPS is a promising strategy to increase the killing of cancer cells while irradiating fast PBs. In fact, the results of this study confirm the ability of GNPS to enhance treatment by increasing the absorbed dose in breast tumors using proton therapy.

Low-Cost and Easily Fabricated Ultrasound-Guided Breast Phantom for Breast Biopsy Training

We aimed to develop an inexpensive and easy-to-fabricate gelatin-based training phantom for improving the breast biopsy skill and confidence level of residents. Young’s modulus and acoustic properties of the gelatin tissue phantom and simulated tumors were investigated. Six residents were requested to evaluate the effectiveness of the breast phantom. The results showed that 83% (n = 5) of the participants agreed that the ultrasound image quality produced by the breast phantom was excellent or good. Only 17% (n = 1) of the participants claimed that there was room for improvement for the haptic feedback they received during the placement of the core needle into the breast phantom. The mean pre-instructional score was 17% (SD 17%) for all participants. The mean post-instructional score was 83% (SD 17%), giving an overall improvement of 67%. In conclusion, the mean needle biopsy skill and confidence levels of the participants substantially increased through simulation training on our breast phantom. The participants’ feedback showed the phantom is sufficiently realistic in terms of ultrasound imaging and haptic feedback during needle insertion; thus, the training outcome can be linked to the performance of residents when they perform a live biopsy.

A feasibility study of time of flight cone beam computed tomography imaging

BACKGROUND: The time of flight (TOF) cone beam computed tomography (CBCT) was recently shown to reduce the X-ray scattering effects by 95%and improve the image CNR by 110%for large volume objects. The advancements in X-ray sources like in compact Free Electron Lasers (FEL) and advancements in detector technology show potential for the TOF method to be feasible in CBCT when imaging large objects. OBJECTIVE: To investigate feasibility and efficacy of TOF CBCT in imaging smaller objects with different targets such as bones and tumors embedded inside the background. METHODS: The TOF method used in this work was verified using a 24cm phantom. Then, the GATE software was used to simulate the CBCT imaging of an 8 cm diameter cylindrical water phantom with two bone targets using a modeled 20 keV quasi-energetic FEL source and various TOF resolutions ranging from 1 to 1000 ps. An inhomogeneous breast phantom of similar size with tumor targets was also imaged using the same system setup. RESULTS: The same results were obtained in the 24cm phantom, which validated the applied CBCT simulation approach. For the case of 8cm cylindrical phantom and bone target, a TOF resolution of 10 ps improved the image contrast-to-noise ratio (CNR) by 57%and reduced the scatter-to-primary ratio (SPR) by 8.63. For the case of breast phantom and tumor target, image CNR was enhanced by 12%and SPR was reduced by 1.35 at 5 ps temporal resolution. CONCLUSIONS: This study indicates that a TOF resolution below 10 ps is required to observe notable enhancements in the image quality and scatter reduction for small objects around 8cm in diameter. The strong scattering targets such as bone can result in substantial improvements by using TOF CBCT.

Compact Wideband Microstrip Patch Antenna Design for Breast Cancer Detection

The current breast cancer detection techniques are mostly invasive and suffer from high cost, high false rate and inefficacy in early detection. These limitations can be subdued by development of non-invasive microwave detection system whose performance is predominantly dependent on the antenna used in the system. The designing of a compact wideband antenna and matching its impedance with breast phantom is a challenging task. In this paper, we have designed a compact antenna matched with the breast phantom operating in wideband frequency from 1 to 6 GHz capable to detect the dielectric (or impedance) contrast of the benign and malignant tissue. The impedance of the antenna is matched to a cubically shaped breast phantom and a very small tumor (volume=1 cm3). The antenna is tuned to the possible range of electrical properties of breast phantom and tumour (permittivity ranging from 10 to 20 and conductivity from 1.5 to 2.5 S/m). The return loss (S11), E-field distribution and specific absorption rate (SAR) are simulated. The operating band of antenna placed near the phantom without tumor was found to be (1.11-5.47)GHz and with tumor inside phantom is (1.29-5.50)GHz. Results also show that the SAR of the antenna is within the safety limit.