Find Virtual Phantoms at AAPM 2024!
Virtual Phantoms CTO Peter Caracappa will be at the 2024 meeting of the American Association of Physicists in Medicine — set up a demonstration or meet to talk about our new features. Call or text 518-288-7860 to set up a meeting See you in Los Angeles!
Read MoreNew Update to VirtualDoseIR Released
Virtual Phantoms is happy to announce a major update of the VirtualDoseIR module has been released for public use. Key new features: Rectangular fields — VirtualDoseIR now models rectangular exposure fields in addition to square ones. Additional cardinal directions — The system now natively supports projections originating on the anterior side of the patient body, plus cranial and caudal tilt angles Spin acquisition — in addition to regular fluoroscopic exposures, there is now an option to estimate the dose from 3D (CBCT) spin acquisitions that have become common on many modern machines. Specify reference point distance — users may now specify the distance from the source to the interventional reference point to override the default reference point position In addition there have been a number of internal improvements to improve the speed and accuracy of the calculations. Features are available today for use with the VirtualDoseIR API — look for updates to the web interface in the near future to take advantage of all new...
Read MoreVirtual Phantoms CEO Dr. George Xu presents keynote address to CIRMS meeting
On April 13, 2022, Prof. George Xu delivered a 45-minutes capstone talk entitled ” Radiotherapy Plan QA using Deep-CNN based Multi-OAR Auto segmentation and GPU-accelerated Monte Carlo Dose Check ” for the CIRMS annual conference. Professor Xu introduced the history of computational phantoms, the VirtualDose software (For tracking patient organ doses from CT and interventional radiology procedures), DeepViewer software (an AI-based automatic multi-organ segmentation tool for radiation therapy) and ArcherQA software (the fast Monte Carlo simulation software for radiation treatment based on GPU acceleration). CIRMS（Council on Ionizing Radiation Measurements and Standards）is the highest academic institution in the field of ionizing radiation measurements and standards in the United States. Its leaders are top experts from industry, academia and government. Through publication of “Needs” report, CIRMS sets national priority in research and development pertaining to ionizing radiation measurement and standardization covering nuclear energy, industrial irradiation, medicine, and nuclear security in the United States. Prof. Xu was elected the President (1999-2000) of the CIRMS, and was chosen to receive the Randall S. Caswell Award in recognition of his outstanding contribution in...
Read MoreDr. Xu Presents Webinar to International Organization for Medical Physics – Wednesday, October 6, 2021
Virtual Phantoms CEO Dr. X George Xu has been invited to present a webinar to the IOMP entitled “New Tools of Phantoms, Monte Carlo Calculations, and AI for Medical Physics Applications” on Wednesday, October 6, 2021. He will speak about: Estimation of organ doses in medical physics depends on computational phantoms and Monte Carlo calculations ─ two tools that have seen major advancement recently. Phantoms have evolved from the 1st-generation stylized phantoms to 2nd-generation voxel phantoms, and to 3rd-generation boundary representative (BREP) phantoms. Aided with the latest deep-learning image segmentation tools, patient-specific phantoms can be created consisting of organ outlines ready for Monte Carlo calculations. And GPU-based Monte Carlo codes can reduce dose computing time from hours to less than one minute. This presentation will cover: (1) Historical review of computational phantoms and Monte Carlo codes, (2) Development of patient-specific phantoms using an automatic multi-organ segmentation tool, DeepViewer, that is based on neural convolutional network (called U-Net) , (3) Development of rapid Monte Carlo dose calculation code, Archer, that is based on nVidia GPU co-processors and virtual-source-modeling of medical accelerators. Examples in medical imaging dose (CT, PET/CT) and radiation treatment will be discussed. To join the webinar – register...
Read MoreLow-dose CT useful in COVID-19 assessment
According to a recent article by AuntMinnie.com, chest CT of 1 mSv or less can accurately and rapidly assess COVID-19 infection in emergency room patients, especially for those who have had symptoms longer than 48 hours. These findings are reported on April 21, 2020 in Radiology: Cardiothoracic Imaging by Dangis et al. Dr. Anthony Dangis of Imelda Hospital in Bonheiden, Belgium who is the corresponding author of the study says: “[We found] an estimated radiation dose reduction by a factor of five,” the group wrote. “Given the widespread use of chest CT for COVID-19 detection, our results demonstrate the feasibility of using low-dose chest CT to achieve an important reduction in radiation dose on a population level during this pandemic.” Real time polymerase chain reaction (RT-PCR) testing is currently the gold standard for diagnosing COVID-19, but its sensitivity can be as low as 70%, the group noted. Chest CT offers an additional diagnostic tool for the disease, with a sensitivity of more than 90%, according to some studies. Example CT images in two patients with COVID-19. Axial (A) and coronal (B) CT imaging in an 85-year-old woman presenting with dyspnea and fever for three days. CT shows typical early COVID-19 findings with bilateral subpleural areas of ground-glass opacities (arrows). Effective radiation dose was 0.52 mSv. Axial (C) and coronal (D) CT images in a 41-year-old woman presenting with a cough and fever for 14 days. CT shows typical late COVID-19 findings with multifocal bilateral subpleural areas of consolidation (arrows). Effective radiation dose was 0.53 mSv. Images and caption courtesy of the RSNA. But CT exams can impart radiation dose to patients — and interpretation of CT images can take time. So how low can CT radiation dose go and still be diagnostic, and how quickly can CT reports be turned around? To find out, Dangis’s team conducted a study of 192 emergency room patients with COVID-19 symptoms who underwent low-dose submillisievert chest CT as well as RT-PCR testing between March 14 and 24. The CT protocol consisted of the following: 100 kVp, 20 mAs, a pitch of 1.2, and gantry rotation time of 0.5 seconds. This team of researchers observe that, of the 192 patients, 43.2% were positive for COVID-19 and 56.8% were negative. Mean patient age was 62, but those patients with the illness were older than those without it (67 years compared with 57 years) and more likely to present with fever (68.7% compared with 45.9%). The group found that low-dose submillisievert chest CT performed well across a variety of measures, especially in patients with symptoms for more than 48 hours. Dangis and colleagues also found that the mean effective radiation dose for their low-dose chest CT protocol was 0.56 mSv. Median time between the acquisition of the CT images and the patient report was 25 minutes (range: 13-49 minutes). Intra- and interreader agreement for the CT exams was 0.96 and 0.95. Low-dose chest CT appears to be an effective additional tool to RT-PCR for diagnosing patients with suspected COVID-19 infection, according to the researchers. “Low-dose chest CT may play a complementary role to RT-PCR for the early triage of patients with possible COVID-19 infection,” they...
Read MoreDr. Xu to receive the 2020 AAPM Quimby Award
Dr. George Xu has been selected to receive the 2020 AAPM Edith H. Quimby Lifetime Achievement Award in Medical Physics (https://news.rpi.edu/approach/2020/01/16).
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