3104 E Camelback Rd No 601
Phoenix AZ 85016
Medical School: Other - Unknown
Accepts Medicare: No
Participates In eRX: No
Participates In PQRS: No
Participates In EHR: No
License #: 14532
Request Appointment Information
Awards & Recognitions
Medical Malpractice Cases
Medical Board Sanctions
CT head-scan dosimetry in an anthropomorphic phantom and associated measurement of ACR accreditation-phantom imaging metrics under clinically representative scan conditions. - Medical physics
To measure radiation absorbed dose and its distribution in an anthropomorphic head phantom under clinically representative scan conditions in three widely used computed tomography (CT) scanners, and to relate those dose values to metrics such as high-contrast resolution, noise, and contrast-to-noise ratio (CNR) in the American College of Radiology CT accreditation phantom.By inserting optically stimulated luminescence dosimeters (OSLDs) in the head of an anthropomorphic phantom specially developed for CT dosimetry (University of Florida, Gainesville), we measured dose with three commonly used scanners (GE Discovery CT750 HD, Siemens Definition, Philips Brilliance 64) at two different clinical sites (Walter Reed National Military Medical Center, National Institutes of Health). The scanners were set to operate with the same data-acquisition and image-reconstruction protocols as used clinically for typical head scans, respective of the practices of each facility for each scanner. We also analyzed images of the ACR CT accreditation phantom with the corresponding protocols. While the Siemens Definition and the Philips Brilliance protocols utilized only conventional, filtered back-projection (FBP) image-reconstruction methods, the GE Discovery also employed its particular version of an adaptive statistical iterative reconstruction (ASIR) algorithm that can be blended in desired proportions with the FBP algorithm. We did an objective image-metrics analysis evaluating the modulation transfer function (MTF), noise power spectrum (NPS), and CNR for images reconstructed with FBP. For images reconstructed with ASIR, we only analyzed the CNR, since MTF and NPS results are expected to depend on the object for iterative reconstruction algorithms.The OSLD measurements showed that the Siemens Definition and the Philips Brilliance scanners (located at two different clinical facilities) yield average absorbed doses in tissue of 42.6 and 43.1 mGy, respectively. The GE Discovery delivers about the same amount of dose (43.7 mGy) when run under similar operating and image-reconstruction conditions, i.e., without tube current modulation and ASIR. The image-metrics analysis likewise showed that the MTF, NPS, and CNR associated with the reconstructed images are mutually comparable when the three scanners are run with similar settings, and differences can be attributed to different edge-enhancement properties of the applied reconstruction filters. Moreover, when the GE scanner was operated with the facility's scanner settings for routine head exams, which apply 50% ASIR and use only approximately half of the 100%-FBP dose, the CNR of the images showed no significant change. Even though the CNR alone is not sufficient to characterize the image quality and justify any dose reduction claims, it can be useful as a constancy test metric.This work presents a straightforward method to connect direct measurements of CT dose with objective image metrics such as high-contrast resolution, noise, and CNR. It demonstrates that OSLD measurements in an anthropomorphic head phantom allow a realistic and locally precise estimation of magnitude and spatial distribution of dose in tissue delivered during a typical CT head scan. Additional objective analysis of the images of the ACR accreditation phantom can be used to relate the measured doses to high contrast resolution, noise, and CNR.
My experience of analysis with Loewald. - The Psychoanalytic quarterly
In this article, the author draws on his experience as Loewald's analysand to explore Loewald's outlook on therapeutic action. Selected references from Loewald's writings and commentary about him from others amplify this exploration. The author also notes how his analysis informed his own development as an analyst, and comments on analytic training in the late 1960s. In addition, he describes Loewald's unique position as a linchpin between ego psychology and the contemporary analytic schools of thought that are based on a two-person psychology.
Enactments in Psychoanalysis: Therapeutic Benefits. - Psychodynamic psychiatry
The therapeutic benefits of enactments are addressed. Relevant literature reveals disparate conceptions about the nature and use of enactments. Clarification of the term is discussed. This analyst's theoretical and technical evolution is addressed; it is inextricably related to using enactments. How can it not be? A taxonomy of enactments is presented. The article considers that enactments may be fundamental in the evolution from orthodox to contemporary analytic technique. Assumptions underlying enactments are explored, as are guidelines for using enactments. Finally, the article posits that enactments have widened the scope of analysis and contributed to its vitality.
Map & Directions
3104 E Camelback Rd No 601 Phoenix, AZ 85016
1661 E Camelback Rd Arizona Pathology Group
4131 N 24Th St Suite B102
5124 N 31St Pl #544