Evaluation of a new image reconstruction method for digital breast tomosynthesis: effects on the visibility of breast lesions and breast density.

Objective: To compare image quality and breast density of two reconstruction methods, the widely-used filtered-back projection (FBP) reconstruction and the iterative heuristic Bayesian inference reconstruction (Bayesian inference reconstruction plus the method of total variation applied, HBI).

Methods: Thirty-two clinical DBT data sets with malignant and benign findings, = 27 and 17, respectively, were reconstructed using FBP and HBI. Three experienced radiologists evaluated the images independently using a 5-point visual grading scale and classified breast density according to the American College of Radiology Breast Imaging-Reporting And Data System Atlas, fifth edition.

Automated ultrafast kilovoltage-megavoltage cone-beam CT for image guided radiotherapy of lung cancer: System description and real-time results.

Purpose: To establish a fully automated kV-MV CBCT imaging method on a clinical linear accelerator that allows image acquisition of thoracic targets for patient positioning within one breath-hold (∼15s) under realistic clinical conditions.

Methods And Materials: Our previously developed FPGA-based hardware unit which allows synchronized kV-MV CBCT projection acquisition is connected to a clinical linear accelerator system via a multi-pin switch; i.e.

Phantom-based evaluation of dose exposure of ultrafast combined kV-MV-CBCT towards clinical implementation for IGRT of lung cancer.

Purpose: Combined ultrafast 90°+90° kV-MV-CBCT within single breath-hold of 15s has high clinical potential for accelerating imaging for lung cancer patients treated with deep inspiration breath-hold (DIBH). For clinical feasibility of kV-MV-CBCT, dose exposure has to be small compared to prescribed dose. In this study, kV-MV dose output is evaluated and compared to clinically-established kV-CBCT.

Towards clinical implementation of ultrafast combined kV-MV CBCT for IGRT of lung cancer : Evaluation of registration accuracy based on phantom study.

Purpose: Combined kV-MV cone-beam CT (CBCT) is a promising approach to accelerate imaging for patients with lung tumors treated with deep inspiration breath-hold. During a single breath-hold (15 s), a 3D kV-MV CBCT can be acquired, thus minimizing motion artifacts and increasing patient comfort. Prior to clinical implementation, positioning accuracy was evaluated and compared to clinically established imaging techniques.

A Novel Analysis Technique for Transcutaneous Measurement of Glomerular Filtration Rate With Ultralow Dose Marker Concentrations.

Objective: A novel high-precision approach [lifetime-decomposition measurement (LTDM)] for the assessment of the glomerular filtration rate (GFR) based on clearance measurements of exogenous filtration marker.

Methods: The time-correlated single photon counting (TCSPC) acquisition in combination with a new decomposition method allows the separation of signal and background from transcutaneous measurements of GFR.

Results: The performance of LTDM is compared versus the commercially available NIC-kidney patch-based system for transcutaneous GFR measurement.

Incorporation of local dependent reliability information into the Prior Image Constrained Compressed Sensing (PICCS) reconstruction algorithm.

Purpose: The reduction of dose in cone beam computer tomography (CBCT) arises from the decrease of the tube current for each projection as well as from the reduction of the number of projections. In order to maintain good image quality, sophisticated image reconstruction techniques are required. The Prior Image Constrained Compressed Sensing (PICCS) incorporates prior images into the reconstruction algorithm and outperforms the widespread used Feldkamp-Davis-Kress-algorithm (FDK) when the number of projections is reduced.

Reliability of transcutaneous measurement of renal function in various strains of conscious mice.

Measuring renal function in laboratory animals using blood and/or urine sampling is not only labor-intensive but puts also a strain on the animal. Several approaches for fluorescence based transcutaneous measurement of the glomerular filtration rate (GFR) in laboratory animals have been developed. They allow the measurement of GFR based on the elimination kinetics of fluorescent exogenous markers.

Transcutaneous measurement of renal function in conscious mice.

Determination of glomerular filtration rate (GFR) in conscious mice is cumbersome for the experimenter and stressful for the animals. Here we report on a simple new technique allowing the transcutaneous measurement of GFR in conscious mice. This approach extends our previously developed technique for rats to mice.

Online feedback-controlled renal constant infusion clearances in rats.

Constant infusion clearance techniques using exogenous renal markers are considered the gold standard for assessing the glomerular filtration rate. Here we describe a constant infusion clearance method in rats allowing the real-time monitoring of steady-state conditions using an automated closed-loop approach based on the transcutaneous measurement of the renal marker FITC-sinistrin. In order to optimize parameters to reach steady-state conditions as fast as possible, a Matlab-based simulation tool was established.

Automation of clip localization in Digital Tomosynthesis for setup of breast cancer patients.

The objective of this study is to develop an automatic clip localization procedure for breast cancer patient setup based on Digital Tomosynthesis (DTS) and to characterize its performance with respect to the overall registration accuracy and robustness. The study was performed under an IRB-approved protocol for 12 breast cancer patients with surgical clips implanted around the tumor cavity. The registration of DTS images to planning CTs was performed using an automatic algorithm developed to overcome specific challenges of localization and registration of clips in the breast setup images.

Transcutaneous assessment of renal function in conscious rats with a device for measuring FITC-sinistrin disappearance curves.

Determination of the urinary or plasma clearance of exogenous renal markers, such as inulin or iohexol, is considered to be the gold standard for glomerular filtration rate (GFR) measurement. Here, we describe a technique allowing determination of renal function based on transcutaneously measured elimination kinetics of fluorescein isothiocyanate (FITC)-sinistrin, the FITC-labeled active pharmaceutical ingredient of a commercially available marker of GFR. A low cost device transcutaneously excites FITC-sinistrin at 480  nm and detects the emitted light through the skin at 520  nm.

Fast kilovoltage/megavoltage (kVMV) breathhold cone-beam CT for image-guided radiotherapy of lung cancer.

Long image acquisition times of 60-120 s for cone-beam CT (CBCT) limit the number of patients with lung cancer who can undergo volume image guidance under breathhold. We developed a low-dose dual-energy kilovoltage-megavoltage-cone-beam CT (kVMV-CBCT) based on a clinical treatment unit reducing imaging time to < or =15 s. Simultaneous kVMV-imaging was achieved by dedicated synchronization hardware controlling the output of the linear accelerator (linac) based on detector panel readout signals, preventing imaging artifacts from interference of the linac's MV-irradiation and panel readouts.

Breath-hold target localization with simultaneous kilovoltage/megavoltage cone-beam computed tomography and fast reconstruction.

Purpose: Hypofractionated high-dose radiotherapy for small lung tumors has typically been based on stereotaxy. Cone-beam computed tomography and breath-hold techniques have provided a noninvasive basis for precise cranial and extracranial patient positioning. The cone-beam computed tomography acquisition time of 60 s, however, is beyond the breath-hold capacity of patients, resulting in respiratory motion artifacts.

Evaluation of clip localization for different kilovoltage imaging modalities as applied to partial breast irradiation setup.

Surgical clip localization and image quality were evaluated for different types of kilovoltage cone beam imaging modalities as applied to partial breast irradiation (PBI) setup. These modalities included (i) clinically available radiographs and cone beam CT (CB-CT) and (ii) various alternative modalities based on partial/sparse/truncated CB-CT. An anthropomorphic torso-breast phantom with surgical clips was used for the imaging studies.