AAPM Task Group Report 261: Comprehensive quality control methodology and management of dental and maxillofacial cone beam computed tomography (CBCT) systems.

Cone-beam computed tomography (CBCT) systems specifically designed and manufactured for dental, maxillofacial imaging (MFI) and otolaryngology (OLR) applications have been commercially available in the United States since 2001 and have been in widespread clinical use since. Until recently, there has been a lack of professional guidance available for medical physicists about how to assess and evaluate the performance of these systems and about the establishment and management of quality control (QC) programs. The owners and users of dental CBCT systems may have only a rudimentary understanding of this technology, including how it differs from conventional multidetector CT (MDCT) in terms of acceptable radiation safety practices.

Impact of multidetector computed tomography scan parameters, novel reconstruction settings, and lung nodule characteristics on nodule diameter measurements: A phantom study.

Purpose: Novel CT reconstruction techniques strive to maintain image quality and processing efficiency. The purpose of this study is to investigate the impact of a newer hybrid iterative reconstruction technique, Adaptive Statistical Iterative Reconstruction-V (ASIR-V), in combination with various CT scan parameters on the semi-automated quantification using various lung nodules.

Methods: A chest phantom embedded with eight spherical objects was scanned using varying CT parameters such as tube current and ASIR-V levels.

Dose, Benefit, and Risk in Medical Imaging, 1 Edition.

When interacting with colleagues, patients, and members of the public, medical physicists are frequently asked questions about radiation doses, clinical benefits, and biological risks of medical imaging. This book collects some of the latest data and understanding on these subjects into a single concise and well-organized volume and makes it accessible to a wide variety of potential readers. The editors and many of the chapter authors are from Memorial Sloan Kettering Cancer Center.

A Phantom Study and a Retrospective Clinical Analysis to Investigate the Impact of a New Image Processing Technology on Radiation Dose and Image Quality during Hepatic Embolization.

Purpose: To investigate changes in radiation dose and image quality using phantoms and hepatic embolization procedures performed with a new image processing technology (ClarityIQ) for a single-plane flat-detector-based interventional fluoroscopy system.

Materials And Methods: Phantom study was performed using acrylic sheets simulating different patient sizes. Air kerma rates (AKRs) were compared for different fluoroscopy modes and magnification modes without and with ClarityIQ.

Evaluation of coronary artery image quality with knowledge-based iterative model reconstruction.

Rationale And Objectives: To evaluate knowledge-based iterative model reconstruction (IMR) to improve image quality and reduce radiation dose in coronary computed tomography angiography (cCTA).

Materials And Methods: We evaluated 45 consecutive cCTA studies, including 25 studies performed with an 80% systolic dose reduction using tube current modulation (TCM). Each study was reconstructed with filtered back projection (FBP), hybrid iterative reconstruction (iDose(4)), and IMR in a diastolic phase.

Cost and radiation savings of partial substitution of ultrasound for CT in appendicitis evaluation: a national projection.

Objective: The costs of an ultrasound-CT protocol and a CT-only protocol for an appendicitis evaluation are compared. For the ultrasound-CT protocol, patients with right lower quadrant abdominal pain undergo an ultrasound examination. If it is positive for appendicitis, they are sent directly to surgery, avoiding CT.

Flow diversion versus traditional aneurysm embolization strategies: analysis of fluoroscopy and procedure times.

Background And Objective: Flow diverters are increasingly used for treatment of complex intracranial aneurysms. The purpose of this study was to compare the pipeline embolization device (PED) and traditional embolization strategies in terms of fluoroscopy and procedure time.

Material And Methods: Fluoroscopy and procedure times (in minutes) were retrospectively analyzed and compared between 127 patients treated with the PED, 86 patients treated with single stage stent assisted coiling (SAC), and 16 patients treated with Onyx HD 500 at our institution.

Extraction of CT dose information from DICOM metadata: automated Matlab-based approach.

Objective: The purpose of this study was to extract exposure parameters and dose-relevant indexes of CT examinations from information embedded in DICOM metadata.

Conclusion: DICOM dose report files were identified and retrieved from a PACS. An automated software program was used to extract from these files information from the structured elements in the DICOM metadata relevant to exposure.

SU-E-I-103: Detecting Anomalous Pixels and Correlated Artifacts in Digital Detectors from Flat-Field Images.

Purpose: Anomalous pixels may be defined as those pixels whose exposure response relationship is deviant from the typical, expected or calibrated response. A group of anomalous pixels may Result in visible correlated artifacts. Here we demonstrate an approach to identify anomalous pixels and correlated artifacts using flat-field images.

SU-E-I-101: Initial Implementation and Evaluation of AAPM TG-150 Draft Image Receptor Non-Uniformity Testing Recommendations.

Purpose: To implement in software the procedures described in AAPM Task Group 150's draft recommendations for image receptor performance testing, and to evaluate the effectiveness and practicality of these procedures.

Methods: Images of flat fields were acquired using digital x-ray image receptors at 6 cooperating institutions. Four flat field images obtained with each detector spanned a range of input detector air kerma.

An exposure indicator for digital radiography: AAPM Task Group 116 (executive summary).

Digital radiographic imaging systems, such as those using photostimulable storage phosphor, amorphous selenium, amorphous silicon, CCD, and MOSFET technology, can produce adequate image quality over a much broader range of exposure levels than that of screen/film imaging systems. In screen/film imaging, the final image brightness and contrast are indicative of over- and underexposure. In digital imaging, brightness and contrast are often determined entirely by digital postprocessing of the acquired image data.

A novel approach to reduce breast radiation exposure with coronary CTA: angled axial image acquisition.

Rationale And Objectives: To determine whether angled gantry acquisition might be used to image the heart with a shorter scan length and reduced breast exposure during coronary computed tomography angiography.

Materials And Methods: One hundred consecutive coronary computed tomography angiography examinations of female patients were retrospectively evaluated to define the angle between the long axis of the left heart and the axial imaging plane. The scan length required to image the entire left ventricle along with the coronary arteries was measured for an axial scan plane as well as for a scan plane parallel to the long axis of the left heart.

Radiation dose in a "triple rule-out" coronary CT angiography protocol of emergency department patients using 64-MDCT: the impact of ECG-based tube current modulation on age, sex, and body mass index.

Objective: "Triple rule-out" coronary CT angiography (CTA) using 64-MDCT technology is a new approach for evaluating emergency department patients presenting with symptoms suggestive of acute coronary syndrome (ACS). Our objective was to evaluate the reduction in effective radiation dose through the use of tube current modulation in patients who underwent a triple rule-out coronary CTA evaluation and to document how effective radiation dose was impacted by patient age, sex, and body mass index (BMI).

Materials And Methods: A retrospective analysis of triple rule-out coronary CTA examinations performed on a 64-MDCT scanner was ordered on a prospective cohort of 267 consecutive low- to moderate-risk emergency department patients with suspected ACS from a single university hospital between October 2006 and March 2008.

Preferential amplification is minimised in long-PCR systems.

The advent of long PCR (XL-PCR) has proven to be a major advance in PCR technology and is currently being utilised to investigate numerous biological systems. The analysis of mixed DNA populations is a particularly useful application for XL-PCR. For example, XL-PCR has been used to investigate the occurrence of heterogeneous mitochondrial DNA (mtDNA) rearrangement mutations.

Gastrointestinal imaging: a systems analysis comparing digital and conventional techniques.

Objective: The purpose of this study was to compare digital and conventional methods of gastrointestinal imaging based on the cost of image storage and estimated overall costs, radiation exposure to the patient, and duration of the examination.

Materials And Methods: Our study sample consisted of 128 patients who underwent conventional gastrointestinal studies (64 double-contrast upper gastrointestinal examinations and 64 double-contrast barium enemas) and 139 patients who underwent digital gastrointestinal studies (66 double-contrast upper gastrointestinal examinations and 73 double-contrast barium enemas). The number of images and films for each study was recorded, and the mean cost of image storage and the estimated overall costs for digital versus conventional studies were calculated.

The universality of bioenergetic disease. Age-associated cellular bioenergetic degradation and amelioration therapy.

During the present century there has been a dramatic change in life expectancy in advanced societies, now exceeding 80 years. As distinct from life expectancy, life potential is said to be at least 120 years, so that the continuing increase in knowledge has the potential for further major changes in the survival of humans conceivably in the near future. This presentation will be concerned with one aspect of the development of biomedical advances related in part to a concept of an "age-related universality of bioenergetic disease," and its potential amelioration and proposed impact on age-related disease and lifestyle.

The age-associated decrease in the amount of amplifiable full-length mitochondrial DNA in human skeletal muscle.

There has been a continuous evolution in our concept [1] that mtDNA undergoes a range of mutations with age and that such alterations lead to a decline in mitochondrial bioenergy capacity. Here we report that a wide range of deletion mutations accumulate with age and the amount of full-length mtDNA (FLmtDNA) amplifiable by extra-long PCR (XL-PCR) markedly decreases with age. An analysis of single human quadriceps muscle fibres reveals a close correlation between the decrease in FLmtDNA and the decline in cytochrome c oxidase activity, an exemplifier of mitochondrial bioenergy.