Summary form only given. Strictly speaking, the maximum injected current for a time-independent c... more Summary form only given. Strictly speaking, the maximum injected current for a time-independent cycloidal flow in a relativistic, magnetically insulated diode has never been correctly solved. Lovelace and Ott (1974) assumed the space charge limited (SCL) condition on the cathode surface in their classic paper. They included the self electric and magnetic fields of the cycloidal flow. Their result is
Intense, ultrashort pulsed electric fields have been studied for applications ranging from killin... more Intense, ultrashort pulsed electric fields have been studied for applications ranging from killing cells in suspension to reducing tumor size [1]. Recent work at the University of Michigan has focused on applying multiple ultrawideband pulsed electric fields with chemotherapeutics to obtain a synergistic effect in killing cancer cells [2]. While bulk temperature measurements indicate that these experiments have slight to no change in temperature, there remain questions about quantifying the thermal effects so that their importance compared to the electrical effects can be assessed. To estimate the thermal effects induced by applying electrical pulses of different pulse duration and intensity to cells in suspension, we apply a recent model of the Ohmic heating of spherical particulates with an arbitrary electrical conductivity exposed to an rf electric field [3]. The possible relevance of these results with regard to pulse-induced thermal effects will be discussed. [1] K. H. Schoenba...
Experimental results are presented for a research program in which high voltage, short-pulsed, ul... more Experimental results are presented for a research program in which high voltage, short-pulsed, ultrawideband electric fields have been demonstrated to enhance the effects of chemotherapy upon killing of Jurkat (cancer) cells. Electric fields of about 100kV/cm have been shown to enhance the killing of Jurkat cells by up to a factor of 1,000 over a low dose of the drug bleomycin. Enhancement of chemotherapy was also found at lower electric fields of 50 kV/cm and higher electric fields up to 200 kV/cm. The cellular mechanism by which the electric fields enhance cell death occurs appears to be independent of caspase activation and hence does not involve classical apoptosis. Rather, the lack of caspase involvement in the UWB mediated cell killing is consistent with "pseuodapoptosis" observed previously with high concentrations of bleomycin. Earlier experiments explored the effects of narrowband RF on conventional electroporation. Addition of radio frequency modulation to a stan...
Third IEEE International Vacuum Electronics Conference (IEEE Cat. No.02EX524)
This paper is a progress report on the relativistic magnetron experiment. It also presents, for t... more This paper is a progress report on the relativistic magnetron experiment. It also presents, for the first time, the maximum emission current density for time-independent, relativistic, cycloidal electron flows in a magnetically insulated diode.
Twenty Seventh International Conference on Infrared and Millimeter Waves
Experiments are underway to investigate the effects of cathode endcaps on electron current loss a... more Experiments are underway to investigate the effects of cathode endcaps on electron current loss and efficiency in relativistic magnetrons. Experiments generate 180-300 MW microwave pulses at 1 GHz from MELBA-C electron beams with parameters: 400 keV, 6 kA, and 500 ns. Data show a four-fold reduction in endloss current with a single endcap. Double end caps are under experimentation.
The maximum emission current density is calculated for a time-independent, relativistic, cycloida... more The maximum emission current density is calculated for a time-independent, relativistic, cycloidal electron flow in a diode that is under the condition of magnetic insulation. Contrary to conventional thinking, this maximum current is not determined by the space charge limited condition on the cathode, even when the emission velocity of the electrons is assumed to be zero. The self electric and magnetic fields associated with the cycloidal flow are completely accounted for. This maximum current density is confirmed by a two-dimensional, fully electromagnetic and fully relativistic particle-in-cell code.
Recent research in cancer progression and treatment indicates that many forms of cancer arise fro... more Recent research in cancer progression and treatment indicates that many forms of cancer arise from the development of a small subpopulation of abnormal cancer stem cells (CSCs) that promote cancer growth and spread. Many potential treatments preferentially interact with cells at certain stages of the cell cycle by either selective killing or halting the cell cycle, such as intense, nanosecond-duration pulsed electric fields (nsPEFs). Simple mathematical models of unfed cancer cell populations at the plateau of their growth characteristics may estimate the long-term consequences of these treatments on proliferating and quiescent cell populations. Applying such a model with no transition from the quiescent to proliferating state shows that it is possible for the proliferating cell population to fall below 1 if the quiescent cell population obtains a sufficient competitive advantage with respect to nutrient consumption and /or survival rate. Introducing small, realistic transition rates did not appreciably alter short-term or long-term population behaviour, indicating that the predicted small cell population behaviour (< 1 cell) is not an artefact of the simpler model. Experimental observations of nsPEF-induced effects on the cell cycle suggest that such a model may serve as a first step in assessing the viability of a given cancer treatment in vitro prior to clinical application.
PurposeA Positron Emission Tomography/Computed Tomography quality assurance program is necessary ... more PurposeA Positron Emission Tomography/Computed Tomography quality assurance program is necessary to ensure that patients receive optimal imaging and care. We summarize the AAPM Task Group (TG) 126 report on acceptance and quality assurance (QA) testing of PET/CT systems.MethodsTG 126 was charged with developing PET/CT acceptance testing and QA procedures. The TG aimed to develop procedures that would allow for standardized evaluation of existing short‐axis cylindrical‐bore PET/CT systems in the spirit of NEMA NU 2 standards without requiring specialized phantoms or proprietary software tools.ResultsWe outline eight performance evaluations using common phantoms and freely available software whereby the clinical physicist monitors each PET/CT system by comparing periodic Follow‐Up Measurements to Baseline Measurements acquired during acceptance testing. For each of the eight evaluations, we also summarize the expected testing time and materials necessary and the recommended pass/fail criteria.ConclusionOur report provides a guideline for periodic evaluations of most clinical PET/CT systems that simplifies procedures and requirements outlined by other agencies and will facilitate performance comparisons across vendors, models, and institutions.
Background: Patients with inflammatory bowel disease (IBD) frequently undergo multiple computed t... more Background: Patients with inflammatory bowel disease (IBD) frequently undergo multiple computed tomography (CT) examinations. With the widespread availability of magnetic resonance imaging (MRI), it is unclear whether the use of CTs in IBD has declined. We aimed to analyze the trends of CT and MRI use in a large cohort of IBD patients in a 10-year period. Methods: We retrospectively analyzed adults ≥18 years of age using a de-identified database, IBM Explorys. Patients with ≥1 CT of the abdomen (± pelvis) or MRI of the abdomen (± pelvis) at least 30 days after the diagnosis of Crohn's disease (CD) or ulcerative colitis (UC) were included. We examined the factors associated with patients undergoing multiple CTs (≥5 CTs of the abdomen) and performed a trend analysis from 2010 to 2019. Results: Among 176 110 CD and 143 460 UC patients, those with ≥1 CT of the abdomen annually increased from 2010 to 2019 with mean annual percentage change of +3.6% for CD and +4.9% for UC. Similarly, annual percentage change for patients with ≥1 MRI (CD: +15.6%; UC: +22.8%) showed a rising trend. There was a 3.8% increase in CD patients receiving ≥5 CTs of the abdomen annually compared with a 2.4% increase among UC patients in the 10-year period. Age ≥50 years, men, African Americans, public insurance payors, body mass index ≥30 kg/ m2, and smoking history were associated with ≥5 CTs. Conclusions: There is a considerable increase in the number of CT scans performed in IBD patients. Further studies can explore factors influencing the use of CT and MRI of the abdomen in IBD patients.
IQ iodine quantification ALARA as low as reasonably possible dsDECT dual-source dual-energy compu... more IQ iodine quantification ALARA as low as reasonably possible dsDECT dual-source dual-energy computed tomography CTDIvol computed tomography dose index volume Rationale and Objectives: Iodine quantification (IQ) and virtual noncontrast (VNC) images produced by dual-energy CT (DECT) can be used for various clinical applications. We investigate the performance of dual-layer DECT (DLDECT) in different phantom sizes and varying radiation doses and tube voltages, including a low-dose pediatric setting. Materials and Methods: Three phantom sizes (simulating a 10-year-old child, an average, and a largesized adult) were scanned with iodine solution inserts with concentrations ranging 0-32 mg/ml, using the DLDECT. Each phantom size was scanned with CTDIvol 2-15 mGy at 120 and 140 kVp. The smallest phantom underwent additional scans with CTDIvol 0.9-1.8 mGy. All scans were repeated 3 times. Each iodine insert was analyzed using VNC and IQ images for accuracy and precision, by comparison to known values. Results: For scans from 2 to 15 mGy mean VNC attenuation and IQ error in the iodine inserts in the small, medium, and large phantoms was 1.2 HU § 3.2, ¡1.2 HU § 14.9, 2.6 HU § 23.6; and +0.1 mg/cc § 0.4, ¡0.9 mg/cc § 0.9, and ¡1.8 mg/cc § 1.8, respectively. In this dose range, there were no significant differences (p 0.05) in mean VNC attenuation or IQ accuracy in each phantom size, while IQ was significantly less precise in the small phantom at 2 mGy and 10 mGy (p < 0.05). Scans with CTDIvol 0.9-1.8 mGy in the small phantom showed a limited, but statistically significantly lower VNC attenuation precision and IQ accuracy (¡0.5 HU § 5.3 and ¡0.3 mg/cc § 0.5, respectively) compared to higher dose scans in the same phantom size. Conclusion: Performance of iodine quantification and subtraction by VNC images in DLDECT is largely dose independent, with the primary factor being patient size. Low-dose pediatric scan protocols have a significant, but limited impact on IQ and VNC attenuation values.
The past decade has seen the increasing integration of magnetic resonance (MR) imaging into radia... more The past decade has seen the increasing integration of magnetic resonance (MR) imaging into radiation therapy (RT). This growth can be contributed to multiple factors, including hardware and software advances that have allowed the acquisition of high-resolution volumetric data of RT patients in their treatment position (also known as MR simulation) and the development of methods to image and quantify tissue function and response to therapy. More recently, the advent of MR-guided radiation therapy (MRgRT)-achieved through the integration of MR imaging systems and linear accelerators-has further accelerated this trend. As MR imaging in RT techniques and technologies, such as MRgRT, gain regulatory approval worldwide, these systems will begin to propagate beyond tertiary care academic medical centers and into more community-based health systems and hospitals, creating new opportunities to provide advanced treatment options to a broader patient population. Accompanying these opportunities are unique challenges related to their adaptation, adoption, and use including modification of hardware and software to meet the unique and distinct demands of MR imaging in RT, the need for standardization of imaging techniques and protocols, education of the broader RT community (particularly in regards to MR safety) as well as the need to continue and support research, and development in this space. In response to this, an ad hoc committee of the American Association of Physicists in Medicine (AAPM) was formed to identify the unmet needs, roadblocks, and opportunities within this space. The purpose of this document is to report on the major findings and recommendations identified. Importantly, the provided recommendations represent the consensus opinions of the committee's membership, which were submitted in the committee's report to the AAPM Board of Directors. In addition, AAPM ad hoc committee reports differ from AAPM task group reports in that ad hoc committee reports are neither reviewed nor ultimately approved by the committee's parent groups, including at the council and executive committee level. Thus, the recommendations given in this summary should not be construed as being endorsed by or official recommendations from the AAPM.
Journal of The American College of Radiology, May 1, 2018
Effective radiation risk communication is a core competency for radiology care providers and can ... more Effective radiation risk communication is a core competency for radiology care providers and can prevent and resolve potential conflicts while helping achieve effective public health safeguards. The authors present a synopsis of the challenges to holding such dialogue and review published methods for strengthening and maintaining this discourse. Twelve strategies are discussed in this article that can help alleviate concerns about the iatrogenic risk associated with medical imaging using radiation exposure.
The chest radiograph is the most frequently performed imaging in radiology and by including the h... more The chest radiograph is the most frequently performed imaging in radiology and by including the heart and central vessels can suggest the presence of cardiovascular disease. Dual-energy subtraction radiography of the chest provides improved detection of a wide variety of cardiovascular pathologies including coronary artery disease, valvular pathologies, and pericardial disease given the presence of calcification in many subtypes of these diseases. We review the principles of dual-energy subtraction radiography and demonstrate its added value in the assessment of cardiovascular disease.
This publication is based on sources and information believed to be reliable, but the AAPM, the a... more This publication is based on sources and information believed to be reliable, but the AAPM, the authors, and the publisher disclaim any warranty or liability based on or relating to the contents of this publication. The AAPM does not endorse any products, manufacturers, or suppliers. Nothing in this publication should be interpreted as implying such endorsement.
Derived from 2 yr of deliberations and community engagement, Medical Physics 3.0 (MP3.0) is an ef... more Derived from 2 yr of deliberations and community engagement, Medical Physics 3.0 (MP3.0) is an effort commissioned by the American Association of Physicists in Medicine (AAPM) to devise a framework of strategies by which medical physicists can maintain and improve their integral roles in, and contributions to, health care and its innovation under conditions of rapid change and uncertainty. Toward that goal, MP3.0 advocates a broadened and refreshed model of sustainable excellence by which medical physicists can and should contribute to health care. The overarching conviction of MP3.0 is that every healthcare facility can benefit from medical physics and every patient's care can be improved by a medical physicist. This large and expansive challenge necessitates a range of strategies specific to each area of medical physics: clinical practice, research, product development, and education. The present paper offers a summary of the Phase 1 deliberations of the MP3.0 initiative pertaining to strategic directions of the discipline primarily but not exclusively oriented toward the clinical practice of medical physics in the United States.
This presentation will highlight the features, benefits, and limitations of solid‐state radiation... more This presentation will highlight the features, benefits, and limitations of solid‐state radiation detectors for diagnostic radiology QC applications. The focus will be on types of solid‐state detectors typically used in commercial portable survey instruments. Practical aspects will include calibration procedures and intervals, directional and energy dependence of detector response, and user options such as configurations, settings, and triggering. The objectives of this session are twofold. First, the user of such instruments should be able to determine which applications are appropriate and inappropriate for a given detector. Second, the user should be able to choose the best detector for a given application.
Summary form only given. Strictly speaking, the maximum injected current for a time-independent c... more Summary form only given. Strictly speaking, the maximum injected current for a time-independent cycloidal flow in a relativistic, magnetically insulated diode has never been correctly solved. Lovelace and Ott (1974) assumed the space charge limited (SCL) condition on the cathode surface in their classic paper. They included the self electric and magnetic fields of the cycloidal flow. Their result is
Intense, ultrashort pulsed electric fields have been studied for applications ranging from killin... more Intense, ultrashort pulsed electric fields have been studied for applications ranging from killing cells in suspension to reducing tumor size [1]. Recent work at the University of Michigan has focused on applying multiple ultrawideband pulsed electric fields with chemotherapeutics to obtain a synergistic effect in killing cancer cells [2]. While bulk temperature measurements indicate that these experiments have slight to no change in temperature, there remain questions about quantifying the thermal effects so that their importance compared to the electrical effects can be assessed. To estimate the thermal effects induced by applying electrical pulses of different pulse duration and intensity to cells in suspension, we apply a recent model of the Ohmic heating of spherical particulates with an arbitrary electrical conductivity exposed to an rf electric field [3]. The possible relevance of these results with regard to pulse-induced thermal effects will be discussed. [1] K. H. Schoenba...
Experimental results are presented for a research program in which high voltage, short-pulsed, ul... more Experimental results are presented for a research program in which high voltage, short-pulsed, ultrawideband electric fields have been demonstrated to enhance the effects of chemotherapy upon killing of Jurkat (cancer) cells. Electric fields of about 100kV/cm have been shown to enhance the killing of Jurkat cells by up to a factor of 1,000 over a low dose of the drug bleomycin. Enhancement of chemotherapy was also found at lower electric fields of 50 kV/cm and higher electric fields up to 200 kV/cm. The cellular mechanism by which the electric fields enhance cell death occurs appears to be independent of caspase activation and hence does not involve classical apoptosis. Rather, the lack of caspase involvement in the UWB mediated cell killing is consistent with "pseuodapoptosis" observed previously with high concentrations of bleomycin. Earlier experiments explored the effects of narrowband RF on conventional electroporation. Addition of radio frequency modulation to a stan...
Third IEEE International Vacuum Electronics Conference (IEEE Cat. No.02EX524)
This paper is a progress report on the relativistic magnetron experiment. It also presents, for t... more This paper is a progress report on the relativistic magnetron experiment. It also presents, for the first time, the maximum emission current density for time-independent, relativistic, cycloidal electron flows in a magnetically insulated diode.
Twenty Seventh International Conference on Infrared and Millimeter Waves
Experiments are underway to investigate the effects of cathode endcaps on electron current loss a... more Experiments are underway to investigate the effects of cathode endcaps on electron current loss and efficiency in relativistic magnetrons. Experiments generate 180-300 MW microwave pulses at 1 GHz from MELBA-C electron beams with parameters: 400 keV, 6 kA, and 500 ns. Data show a four-fold reduction in endloss current with a single endcap. Double end caps are under experimentation.
The maximum emission current density is calculated for a time-independent, relativistic, cycloida... more The maximum emission current density is calculated for a time-independent, relativistic, cycloidal electron flow in a diode that is under the condition of magnetic insulation. Contrary to conventional thinking, this maximum current is not determined by the space charge limited condition on the cathode, even when the emission velocity of the electrons is assumed to be zero. The self electric and magnetic fields associated with the cycloidal flow are completely accounted for. This maximum current density is confirmed by a two-dimensional, fully electromagnetic and fully relativistic particle-in-cell code.
Recent research in cancer progression and treatment indicates that many forms of cancer arise fro... more Recent research in cancer progression and treatment indicates that many forms of cancer arise from the development of a small subpopulation of abnormal cancer stem cells (CSCs) that promote cancer growth and spread. Many potential treatments preferentially interact with cells at certain stages of the cell cycle by either selective killing or halting the cell cycle, such as intense, nanosecond-duration pulsed electric fields (nsPEFs). Simple mathematical models of unfed cancer cell populations at the plateau of their growth characteristics may estimate the long-term consequences of these treatments on proliferating and quiescent cell populations. Applying such a model with no transition from the quiescent to proliferating state shows that it is possible for the proliferating cell population to fall below 1 if the quiescent cell population obtains a sufficient competitive advantage with respect to nutrient consumption and /or survival rate. Introducing small, realistic transition rates did not appreciably alter short-term or long-term population behaviour, indicating that the predicted small cell population behaviour (< 1 cell) is not an artefact of the simpler model. Experimental observations of nsPEF-induced effects on the cell cycle suggest that such a model may serve as a first step in assessing the viability of a given cancer treatment in vitro prior to clinical application.
PurposeA Positron Emission Tomography/Computed Tomography quality assurance program is necessary ... more PurposeA Positron Emission Tomography/Computed Tomography quality assurance program is necessary to ensure that patients receive optimal imaging and care. We summarize the AAPM Task Group (TG) 126 report on acceptance and quality assurance (QA) testing of PET/CT systems.MethodsTG 126 was charged with developing PET/CT acceptance testing and QA procedures. The TG aimed to develop procedures that would allow for standardized evaluation of existing short‐axis cylindrical‐bore PET/CT systems in the spirit of NEMA NU 2 standards without requiring specialized phantoms or proprietary software tools.ResultsWe outline eight performance evaluations using common phantoms and freely available software whereby the clinical physicist monitors each PET/CT system by comparing periodic Follow‐Up Measurements to Baseline Measurements acquired during acceptance testing. For each of the eight evaluations, we also summarize the expected testing time and materials necessary and the recommended pass/fail criteria.ConclusionOur report provides a guideline for periodic evaluations of most clinical PET/CT systems that simplifies procedures and requirements outlined by other agencies and will facilitate performance comparisons across vendors, models, and institutions.
Background: Patients with inflammatory bowel disease (IBD) frequently undergo multiple computed t... more Background: Patients with inflammatory bowel disease (IBD) frequently undergo multiple computed tomography (CT) examinations. With the widespread availability of magnetic resonance imaging (MRI), it is unclear whether the use of CTs in IBD has declined. We aimed to analyze the trends of CT and MRI use in a large cohort of IBD patients in a 10-year period. Methods: We retrospectively analyzed adults ≥18 years of age using a de-identified database, IBM Explorys. Patients with ≥1 CT of the abdomen (± pelvis) or MRI of the abdomen (± pelvis) at least 30 days after the diagnosis of Crohn's disease (CD) or ulcerative colitis (UC) were included. We examined the factors associated with patients undergoing multiple CTs (≥5 CTs of the abdomen) and performed a trend analysis from 2010 to 2019. Results: Among 176 110 CD and 143 460 UC patients, those with ≥1 CT of the abdomen annually increased from 2010 to 2019 with mean annual percentage change of +3.6% for CD and +4.9% for UC. Similarly, annual percentage change for patients with ≥1 MRI (CD: +15.6%; UC: +22.8%) showed a rising trend. There was a 3.8% increase in CD patients receiving ≥5 CTs of the abdomen annually compared with a 2.4% increase among UC patients in the 10-year period. Age ≥50 years, men, African Americans, public insurance payors, body mass index ≥30 kg/ m2, and smoking history were associated with ≥5 CTs. Conclusions: There is a considerable increase in the number of CT scans performed in IBD patients. Further studies can explore factors influencing the use of CT and MRI of the abdomen in IBD patients.
IQ iodine quantification ALARA as low as reasonably possible dsDECT dual-source dual-energy compu... more IQ iodine quantification ALARA as low as reasonably possible dsDECT dual-source dual-energy computed tomography CTDIvol computed tomography dose index volume Rationale and Objectives: Iodine quantification (IQ) and virtual noncontrast (VNC) images produced by dual-energy CT (DECT) can be used for various clinical applications. We investigate the performance of dual-layer DECT (DLDECT) in different phantom sizes and varying radiation doses and tube voltages, including a low-dose pediatric setting. Materials and Methods: Three phantom sizes (simulating a 10-year-old child, an average, and a largesized adult) were scanned with iodine solution inserts with concentrations ranging 0-32 mg/ml, using the DLDECT. Each phantom size was scanned with CTDIvol 2-15 mGy at 120 and 140 kVp. The smallest phantom underwent additional scans with CTDIvol 0.9-1.8 mGy. All scans were repeated 3 times. Each iodine insert was analyzed using VNC and IQ images for accuracy and precision, by comparison to known values. Results: For scans from 2 to 15 mGy mean VNC attenuation and IQ error in the iodine inserts in the small, medium, and large phantoms was 1.2 HU § 3.2, ¡1.2 HU § 14.9, 2.6 HU § 23.6; and +0.1 mg/cc § 0.4, ¡0.9 mg/cc § 0.9, and ¡1.8 mg/cc § 1.8, respectively. In this dose range, there were no significant differences (p 0.05) in mean VNC attenuation or IQ accuracy in each phantom size, while IQ was significantly less precise in the small phantom at 2 mGy and 10 mGy (p < 0.05). Scans with CTDIvol 0.9-1.8 mGy in the small phantom showed a limited, but statistically significantly lower VNC attenuation precision and IQ accuracy (¡0.5 HU § 5.3 and ¡0.3 mg/cc § 0.5, respectively) compared to higher dose scans in the same phantom size. Conclusion: Performance of iodine quantification and subtraction by VNC images in DLDECT is largely dose independent, with the primary factor being patient size. Low-dose pediatric scan protocols have a significant, but limited impact on IQ and VNC attenuation values.
The past decade has seen the increasing integration of magnetic resonance (MR) imaging into radia... more The past decade has seen the increasing integration of magnetic resonance (MR) imaging into radiation therapy (RT). This growth can be contributed to multiple factors, including hardware and software advances that have allowed the acquisition of high-resolution volumetric data of RT patients in their treatment position (also known as MR simulation) and the development of methods to image and quantify tissue function and response to therapy. More recently, the advent of MR-guided radiation therapy (MRgRT)-achieved through the integration of MR imaging systems and linear accelerators-has further accelerated this trend. As MR imaging in RT techniques and technologies, such as MRgRT, gain regulatory approval worldwide, these systems will begin to propagate beyond tertiary care academic medical centers and into more community-based health systems and hospitals, creating new opportunities to provide advanced treatment options to a broader patient population. Accompanying these opportunities are unique challenges related to their adaptation, adoption, and use including modification of hardware and software to meet the unique and distinct demands of MR imaging in RT, the need for standardization of imaging techniques and protocols, education of the broader RT community (particularly in regards to MR safety) as well as the need to continue and support research, and development in this space. In response to this, an ad hoc committee of the American Association of Physicists in Medicine (AAPM) was formed to identify the unmet needs, roadblocks, and opportunities within this space. The purpose of this document is to report on the major findings and recommendations identified. Importantly, the provided recommendations represent the consensus opinions of the committee's membership, which were submitted in the committee's report to the AAPM Board of Directors. In addition, AAPM ad hoc committee reports differ from AAPM task group reports in that ad hoc committee reports are neither reviewed nor ultimately approved by the committee's parent groups, including at the council and executive committee level. Thus, the recommendations given in this summary should not be construed as being endorsed by or official recommendations from the AAPM.
Journal of The American College of Radiology, May 1, 2018
Effective radiation risk communication is a core competency for radiology care providers and can ... more Effective radiation risk communication is a core competency for radiology care providers and can prevent and resolve potential conflicts while helping achieve effective public health safeguards. The authors present a synopsis of the challenges to holding such dialogue and review published methods for strengthening and maintaining this discourse. Twelve strategies are discussed in this article that can help alleviate concerns about the iatrogenic risk associated with medical imaging using radiation exposure.
The chest radiograph is the most frequently performed imaging in radiology and by including the h... more The chest radiograph is the most frequently performed imaging in radiology and by including the heart and central vessels can suggest the presence of cardiovascular disease. Dual-energy subtraction radiography of the chest provides improved detection of a wide variety of cardiovascular pathologies including coronary artery disease, valvular pathologies, and pericardial disease given the presence of calcification in many subtypes of these diseases. We review the principles of dual-energy subtraction radiography and demonstrate its added value in the assessment of cardiovascular disease.
This publication is based on sources and information believed to be reliable, but the AAPM, the a... more This publication is based on sources and information believed to be reliable, but the AAPM, the authors, and the publisher disclaim any warranty or liability based on or relating to the contents of this publication. The AAPM does not endorse any products, manufacturers, or suppliers. Nothing in this publication should be interpreted as implying such endorsement.
Derived from 2 yr of deliberations and community engagement, Medical Physics 3.0 (MP3.0) is an ef... more Derived from 2 yr of deliberations and community engagement, Medical Physics 3.0 (MP3.0) is an effort commissioned by the American Association of Physicists in Medicine (AAPM) to devise a framework of strategies by which medical physicists can maintain and improve their integral roles in, and contributions to, health care and its innovation under conditions of rapid change and uncertainty. Toward that goal, MP3.0 advocates a broadened and refreshed model of sustainable excellence by which medical physicists can and should contribute to health care. The overarching conviction of MP3.0 is that every healthcare facility can benefit from medical physics and every patient's care can be improved by a medical physicist. This large and expansive challenge necessitates a range of strategies specific to each area of medical physics: clinical practice, research, product development, and education. The present paper offers a summary of the Phase 1 deliberations of the MP3.0 initiative pertaining to strategic directions of the discipline primarily but not exclusively oriented toward the clinical practice of medical physics in the United States.
This presentation will highlight the features, benefits, and limitations of solid‐state radiation... more This presentation will highlight the features, benefits, and limitations of solid‐state radiation detectors for diagnostic radiology QC applications. The focus will be on types of solid‐state detectors typically used in commercial portable survey instruments. Practical aspects will include calibration procedures and intervals, directional and energy dependence of detector response, and user options such as configurations, settings, and triggering. The objectives of this session are twofold. First, the user of such instruments should be able to determine which applications are appropriate and inappropriate for a given detector. Second, the user should be able to choose the best detector for a given application.
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Papers by David W Jordan