Radiological Physics and Technology This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Tooth detection for each tooth type by application of faster R-CNNs to divided analysis areas of dental panoramic X-ray images
This study aimed to propose a computerized method for detecting the tooth region for each tooth type as the initial stage in the development of a computer-aided diagnosis (CAD) scheme for dental panoramic X-ray images. Our database consists of 160 panoramic dental X-ray images obtained from 160 adult patients. To reduce false positives (FPs), the proposed method first extracts a rectangular area including all teeth from a dental panoramic X-ray image with a faster region using a convolutional neural network (Faster R-CNN). From the rectangular area including all teeth, six divided areas are then extracted with Faster R-CNN...
Source: Radiological Physics and Technology - May 4, 2022 Category: Physics Source Type: research

The utility of using TACE-assisted software with CBCT in colonic diverticular bleeding without extravascular leakage
AbstractThe utility of three-dimensional (3D) imaging with cone-beam computed tomography (CBCT) during interventional radiology (IVR) in colonic diverticular bleeding was compared to that of contrast-enhanced computed tomography (CECT). Additionally, to identify the responsible vessels in the absence of extravascular leakage using digital subtraction angiography, we examined the detection rate using software conventionally applied to transcatheter arterial chemoembolization (TACE). The 3D images obtained by CECT before IVR did not clearly show the destroyed vessels, whereas the 3D images obtained by CBCT during IVR clearly...
Source: Radiological Physics and Technology - May 4, 2022 Category: Physics Source Type: research

Influence of monitor display resolution and displayed image size on the spatial resolution of ultra-high-resolution CT images: a phantom study
In conclusion, the spatial resolution of UHRCT images may be affected by LCD resolution and displayed image size. To optimize the clinical display conditions for UHRCT images, it is necessary to adopt an LCD with an adequate resolution for each viewing situation. (Source: Radiological Physics and Technology)
Source: Radiological Physics and Technology - April 24, 2022 Category: Physics Source Type: research

The impact of target positioning error and tumor size on radiobiological parameters in robotic stereotactic radiosurgery for metastatic brain tumors
This study aimed to evaluate the effect of target positioning error (TPE) on radiobiological parameters, such as tumor control probability (TCP) and normal tissue complication probability (NTCP), in stereotactic radiosurgery (SRS) for metastatic brain tumors of different sizes using CyberKnife. The reference SRS plans were created using the circular cone of the CyberKnife for each spherical gross tumor volume (GTV) with diameters (φ) of 5, 7.5, 10, 15, and 20  mm, contoured on computed tomography images of the head phantom. Subsequently, plans involving TPE were created by shifting the beam center by 0.1–2.0 mm in thr...
Source: Radiological Physics and Technology - March 7, 2022 Category: Physics Source Type: research

Marker-less and calibration-less motion correction method for brain PET
In this study, we develop a method for positional calibration between the PET system and an external range sensor to achieve practical head motion correction. The basic concept of the developed method involves using the subject ’s face model as a marker not only for head motion detection but also for the system positional calibration. The face model of the subject, which can be obtained easily using the range sensor, can also be calculated from a computed tomography (CT) image of the same subject. The CT image, which is acquired separately for attenuation correction in PET, has the same coordinates as the PET image becau...
Source: Radiological Physics and Technology - March 3, 2022 Category: Physics Source Type: research

Decreased imaging time of amyloid PET using [18F]florbetapir can maintain quantitative accuracy
AbstractShortening the amount of time required to acquire amyloid positron emission tomography (PET) brain images while maintaining the accuracy of quantitative evaluation would help to overcome motion artifacts associated with Alzheimer ’s disease patients. The present study aimed to validate the quantitative accuracy of [18F]florbetapir ([18F]FBP) imaging over a shorter acquisition duration. Forty participants were injected with [18F]FBP, and PET images were acquired for 50 –55, 50–60, and 50–70 min after injection. Three physicians visually assessed the reprocessed [18F]FBP images using a binary scale to classi...
Source: Radiological Physics and Technology - March 3, 2022 Category: Physics Source Type: research

Deep-learning-based fast TOF-PET image reconstruction using direction information
In this study, we propose a novel convolutional neural network (CNN)-based fast time-of-flight PET (TOF-PET) image reconstruction method to fully utilize the direction information of coincidence events. The proposed method inputs view-grouped histo-images into a 3D CNN as a multi-channel image to use the direction information of such events. We evaluated the proposed method using Monte Carlo simulation data obtained from a digital brain phantom. Compared with a case without direction information, the peak signal-to-noise ratio and structural similarity were improved by 1.2  dB and 0.02, respectively, at a coincidence time...
Source: Radiological Physics and Technology - February 8, 2022 Category: Physics Source Type: research

Quantitative analysis of changes in lung density by dynamic chest radiography in association with CT values: a virtual imaging study and initial clinical corroboration
AbstractDynamic chest radiography (DCR) identifies pulmonary impairments as decreased changes in radiographic lung density during respiration ( Δpixel values), but not as scaled/standardized computed tomography (CT) values. Quantitative analysis correlated with CT values is beneficial for a better understanding of Δpixel values in DCR-based assessment of pulmonary function. The present study aimed to correlate Δpixel values from DCR with changes in CT values during respiration (ΔCT values) through a computer-based phantom study. A total of 20 four-dimensional computational phantoms during forced breathing were created ...
Source: Radiological Physics and Technology - January 29, 2022 Category: Physics Source Type: research

Dosiomic feature comparison between dose-calculation algorithms used for lung stereotactic body radiation therapy
AbstractTo evaluate the reproducibility of dose-based radiomic (dosiomic) features between dose-calculation algorithms for lung stereotactic body radiation therapy (SBRT). We analyzed 105 patients with early-stage non-small cell lung cancer who underwent lung SBRT between March 2011 and December 2017. Radiation doses of 48, 60, and 70  Gy were prescribed to the isocenter in 4–8 fractions. Dose calculations were performed using X-ray voxel Monte Carlo (XVMC) on the iPlan radiation treatment planning system (RTPS). Thereafter, the radiation doses were recalculated using the Acuros XB (AXB) and analytical anisotropic algor...
Source: Radiological Physics and Technology - January 24, 2022 Category: Physics Source Type: research