Experimental and Monte Carlo study of energy response of BEO-based OSL detectors within photon energy range up to 15 MeV.

Response of personal dosemeters to high energy photon radiation is of great interest nowadays due to a spread of new radiation technologies and the expansion of occupational exposure domains. ICRU95 publication has expanded the range of relevant photon energies upwards, setting new horizons for individual monitoring. Beryllium oxide (BeO) material is increasingly popular due to its excellent optically stimulated luminescence (OSL) properties, simple readout and reasonable energy response in the low energy (below 100 keV) range. The study considers energy dependence of OSL response at higher photon energies. Energy deposition of monoenergetic photons with energy up to 15 MeV in the BeO chips of various thickness was modeled with Monte Carlo MCNP 6.2 code. Benchmark experiments were conducted at LINAC with high voltage of 6, 10 and 15 MV resulting in respective incident photon spectra. The findings of this study add knowledge regarding behavior of BeO personal dosemeters in the photon fields within the energy range above 3 MeV.

Trends in the Use of Percutaneous Versus Open Surgical Breast Biopsy: An Update.

PURPOSE: Despite the emergence of core-needle (percutaneous) biopsy as the standard of breast care, open surgical breast biopsies continue to be performed with variable frequency. The aim of this study was to compare trends in the use of percutaneous and open surgical breast biopsies and the relative roles of radiologists and surgeons in performing them. METHODS: The nationwide Medicare Part B Physician/Supplier Procedure Summary Master Files for 2004 to 2016 were reviewed, and trends were studied in the total volume of breast biopsies performed in the Medicare fee-for-service population and in volumes of imaging-guided percutaneous biopsies (IGPBs) and open surgical biopsies. Using Medicare's physician specialty codes, the numbers of procedures performed by different specialties were determined. Trends in the type of imaging used for IGPBs were analyzed using the relevant Current Procedural Terminology codes, introduced in 2014. RESULTS: Between 2004 and 2016, utilization of IGPBs increased from 124,423 to 187,914 (+51%), whereas the use of open surgical breast biopsies declined from to 6,605 to 2,373 (-64%). IGPBs performed by radiologists increased from 89,493 to 160,485 (+79%), and IGPBs by surgeons declined from 30,264 to 24,703 (-18%). Among IGPBs from 2014 to 2016, ultrasound-guided and MRI-guided percutaneous biopsies increased, whereas stereotactic biopsies declined. CONCLUSIONS: There is a steady upward trend in the utilization of imaging-guided breast biopsies, and a majority are performed by radiologists. Ultrasound is the primary guidance technique used in percutaneous breast biopsies.

Contrast-enhanced Spectral Mammography: Modality-Specific Artifacts and Other Factors Which May Interfere with Image Quality.

RATIONALE AND OBJECTIVES: Contrast-enhanced spectral mammography (CESM) uses full field digital mammography with the added benefit of intravenous contrast administration to significantly reduce false-positive and false-negative results and improve specificity while maintaining high sensitivity. For CESM to fulfill its purpose, one should be aware of possible artifacts and other factors which may interfere with image quality, and attention should be taken to minimize these factors. MATERIALS AND METHODS: This pictorial demonstration will depict types of artifacts detected and other factors that interfere with image acquisition in our practice since CESM implementation. RESULTS: Many of the artifacts and other factors we have encountered while using CESM have simple solutions to resolve them. CONCLUSION: The illustrated artifacts and other factors interfering with image quality will serve as a useful reference to anyone using CESM.

Contrast-enhanced Spectral Mammography: Technique, Indications, and Clinical Applications.

RATIONALE AND OBJECTIVES: Contrast-enhanced spectral mammography (CESM) combines the benefits of full field digital mammography with the concept of tumor angiogenesis. Technique and practical applications of CESM are discussed. MATERIALS AND METHODS: An overview of the technique is followed by a demonstration of practical applications of CESM in our practice. RESULTS: We have successfully implemented CESM into our practice as a screening, diagnostic, staging, and treatment response tool. CONCLUSION: It is important to understand the technique of CESM and how to incorporate it into practice.

Amyloidosis of the Breast with Multicentric DCIS and Pleomorphic Invasive Lobular Carcinoma in a Patient with Underlying Extranodal Castleman's Disease.

We present an interesting case of focal amyloidosis of the left breast which was intermixed with ductal carcinoma in situ (DCIS). On subsequent staging bilateral breast magnetic resonance imaging (MRI), the patient was found to have an additional suspicious enhancing mass with spiculated borders within the left breast. This mass was biopsy proven to represent pleomorphic invasive lobular carcinoma. A pulmonary nodule within the lingula was also noted on the staging bilateral breast MRI and was biopsy proven to represent extranodal Castleman's disease. Therefore, it is believed that our patient had secondary amyloidosis due to Castleman's disease.

Case report: ductal carcinoma in situ in the male breast.

High-grade ductal carcinoma in situ is incredibly rare in male patients. The prognosis for ductal carcinoma in situ (DCIS) in a male patient is the same as it would be for a female with the same stage disease; therefore, early recognition and diagnosis are of the utmost importance. We present a case of a male with unilateral invasive ductal carcinoma who was diagnosed with DCIS in the contralateral breast. The DCIS presented as microcalcifications on mammography and was found to be biopsy proven grade 3 papillary DCIS. This case also illustrates the importance of family history and risk factors, all of which need to be evaluated in any male presenting with a breast mass or nipple discharge.

Vivo motion and force measurement of surgical needle intervention during prostate brachytherapy.

In this paper, we present needle insertion forces and motion trajectories measured during actual brachytherapy needle insertion while implanting radioactive seeds in the prostate glands of 20 different patients. The needle motion was captured using ultrasound images and a 6 degree-of-freedom electromagnetic-based position sensor. Needle velocity was computed from the position information and the corresponding time stamps. From in vivo data we found the maximum needle insertion forces to be about 15.6 and 8.9 N for 17 gauge (1.47 mm) and 18 gauge (1.27 mm) needles, respectively. Part of this difference in insertion forces is due to the needle size difference (17G and 18G) and the other part is due to the difference in tissue properties that are specific to the individual patient. Some transverse forces were observed, which are attributed to several factors such as tissue heterogeneity, organ movement, human factors in surgery, and the interaction between the template and the needle. However, theses insertion forces are significantly responsible for needle deviation from the desired trajectory and target movement. Therefore, a proper selection of needle and modulated velocity (translational and rotational) may reduce the tissue deformation and target movement by reducing insertion forces and thereby improve the seed delivery accuracy. The knowledge gleaned from this study promises to be useful for not only designing mechanical/robotic systems but also developing a predictive deformation model of the prostate and real-time adaptive controlling of the needle.

In vivo cancer diagnosis with optical spectroscopy and acoustically induced blood stasis using a murine MCa35 model.

Ultrasound-induced blood stasis has been observed for more than 30 years. Most of the literature has been focused on the health risks associated with this phenomenon and methods employed to prevent stasis from occurring during ultrasound imaging. To date, experimental observations have been either in vitro or invasive. The current work demonstrates ultrasound-induced blood stasis in murine normal leg muscle versus tumor-bearing legs, observed through noninvasive measurements of optical spectroscopy, and discusses possible diagnostic uses for this previously undesirable effect of ultrasound. We demonstrate that, using optical spectroscopy, effects of ultrasound can be used to differentiate tumor from normal leg muscle tissue in mice. Finally, we propose a novel diagnostic algorithm that quantitatively differentiates tumor from nontumor with maximum specificity 0.83, maximum sensitivity 0.79, and area under receiver-operating-characteristics curve 0.90.

Bouquet brachytherapy: feasibility and optimization of conically spaced implants.

PURPOSE: To examine the dosimetric feasibility of a conical implantation approach to robotic-assisted prostate brachytherapy. METHODS AND MATERIALS: An in-house inverse planning software based on the genetic algorithm (GA) was used to optimize the needle angulations and the seed positions along needles that form one or two bouquets. Volume data from 20 prostate seed implant patients (six 125I and 14 103Pd) previously treated using the conventional rectilinear template approach were used. The dosimetry outcomes of the optimized treatment plan in the conical approach were compared with those from the original treatment plans based on the conventional rectilinear template approach. RESULTS: When seed spacing is restricted to nominal 1 cm center-to-center spacing, dosimetry results in the conical approach suffer from a higher urethra dose and higher dose heterogeneity compared with the original rectilinear template plans. When the seed loading patterns are optimized as part of inverse planning, the resulting dosimetry plans exhibit adequate dose coverage and uniformity through the target volume, as well as satisfactory sparing of the urethra and rectum. CONCLUSIONS: Conically spaced implantation for prostate brachytherapy with 125I and 103Pd seeds is feasible in terms of dosimetry outcomes. Techniques for optimized inverse planning for this approach have been developed.

Automatic localization of implanted seeds from post-implant CT images.

An automatic localization method of implanted seeds from a series of post-implant computed tomography (CT) images is described in this paper. Post-implant CT studies were obtained for patients who underwent prostate brachytherapy. Bright areas were segmented using binary thresholding in each CT slice, and geometrical information on these areas was collected. Large areas (possibly containing two connected seeds) were split into smaller ones by geometry-based filtering in each slice. The area connectivity along the longitudinal direction was analysed using a geometry-based connection search algorithm executed on every area slice by slice, so that the connected areas were combined into one object. The weighted centroid of each object was taken as the seed position. This method was tested on a seed-containing prostate phantom as well as using CT studies from patients. Statistical analysis demonstrates that it can achieve above 99% detection rate with reliable localization accuracy and high speed. It is reliable and convenient for localizing implanted seeds on CT and can be used to assist post-implant dosimetry for prostate brachytherapy.