About Dr. Nosil
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Education
B.Sc., Solid Stare Physics,
M.Sc. Nuclear and Atomic Physics
D.Sc. Medical Physics
Research
All areas of Diagnostic and Nuclear Medical Physics
Hometown
Vancouver, Canada
Occupation
Diagnostic and Nuclear Medical Physicist
Work Experiences
Europe and Canada
Europe and Canada
UK, Department of Medical Physics of the Royal Postgraduate Medical School, Hammersmith Hospital, London.
I obtained experience in the Radiation Physics group in radiotherapy field planning and dosimetry measurements, particularly in relation to operation of the Linear Accelerator for X-ray and electron therapy. I also took part in physics work in the Diagnostic Radiology Department and had the opportunity to see the arrangements for fast neutron therapy with the cyclotron in the MRC Unit on this site.
I have then taken part in all aspects of the work in the Diagnostic Physics section of the Department including the preparation of radioactively labelled pharmaceuticals for diagnostic procedures, thyroid tests, scanning and gamma camera studies and radiation protection. I also studied the arrangements for preparation of production and supply of short lived radio nuclides. In particular I played a very active part in further cyclotron studies using radioactive nitrogen from the Cyclotron Unit in clinical research studies of lung perfusion and ventilation using the gamma camera and computer on-line data processing. In this connection I had some original developments in the treatment of data to display 'dynamic' images related to regional turnover of the tracer in the lung, work which was published. (Paraphrased from reference letter by prof Oliver)
Canada, University of Calgary, Physics Department
At Calgary, I expanded the diagnostic imaging capabilities and made many improvements in the quality control of radiographic equipment and isotope dosimetry. I played a key role in making the Foothills Hospital one of the foremost hospitals in North America in the application of gamma ray imaging with the Anger camera especially for cardiac and brain imaging. It was a pleasure for me to collaborate with him on a project to determine attenuation coefficients of gamma rays in tissue. This work was subsequently published. In another project, we studied the feasibility of using a coded aperture for diagnostic imaging. Such apertures are used to form X-ray images of astronomical sources. We felt that the device might allow imaging to be carried out using less radiation intensities than are needed for pin-hole imaging. A mosaic of plastic and lead squares was constructed and we succeeded in reconstructing an image of a thyroid phantom. Unfortunately the work had to be discontinued because of lack of funding and suitable computing facilities. (Paraphrased from reference letter by prof Bland, U of C)
Canada, University of Calgary, Faculty of Engineering
My collaboration with Department of Electrical and Computer Engineering covered 3 projects involving edge detection of objects in medical images. Imaging modalities consisted of computed tomographic brain scans and scintigraphic cardiac blood pool images. This work led to several journal publications.
First, Computed Tomography (CT) paper was focused on the caudate nucleus and the need to develop quantitative characterization of it in schizophrenia research. A computer method was described for accurately detecting the edges of the caudate nuclei in CT scans. The method consists of a two dimensional filtering step to reduce image noise, followed by gradient computation for edge enhancement, and then an edge detection step to identify and record the caudate nuclei cross·section:. Results from both head scans and synthetic images indicate that the method is successful even for low-contrast edges wrier the standard deviation of image noise approaches the difference in mean CT number across the edge. The availability of an automated method of delineating the caudate nucleus permits the density to be estimated, and from a set of closely spaced slices, volume information to be obtained.
Second paper. published in Medical Physics, described the dependence of the left ventricular ejection fraction calculation on the background correction in gated cardiac blood pool studies. A simple cardiac model had shown that the election fraction is relatively insensitive to the background correction when an accurately detained variable region of interest is used. With a fixed region of interest the background correction must be accurately estimated. A similar ejection fraction-background correction relationship was obtained in the analysis of clinical cardiac data in nuclear medicine patients. (Paraphrased from reference letter by prof Stein, U of C).
Canada, Foothills Hospital, Calgary, Alberta; Victoria General Hospital, Royal Jubilee Hospital, Greater Victoria Hospital Society, Vancouver Island Hospital Association, and others Hospitals in British Columbia.
My responsibilities were extended to include all Medical Physics services to above sites of the Capital Health Region.
My primary responsibilities as Clinical Medical Radiation Physicist is to standardize and calibrate medical imaging equipment and to ensure the accuracy and safety of the testing methods used. The performance specification, selection, acceptance testing, and quality control of the highly technical and costly equipment is a key part of the position. I am also responsible for providing education, and training in medical physics to physicians, nurses, students and technical staff.
Other areas of responsibility involve (1) the medical physics service, including its financial supervision; (2) GVHS Radiation Safety Officer, having the authority and responsibility for all operations involving radiation; and (3) PACS/Digital Project physicist.
I was responsible for supervising the quality control/radiation safety technologists, Assistant Medical Physicist, programmers, and other professional or technical staff involved in Medical Physics projects and in PACS/Digital Project. My participation in Capital Equipment Assets Management include technical review and equipment/ facility planning, equipment requirements, purchasing, installation, acceptance testing, clinical implementation, quality assurance and quality control of equipment performance, radiation safety, equipment maintenance, evaluation and disposal of clinical systems.
As the Radiation Safety Officer for the Capital Health Region I supervised different individuals including hospital site specific Radiation Protection Officers (RPO) for the use of x-rays, Radioisotope Radiation Safety Officers (RSO) for the use of isotopes, X‑ray Radiation Protection and Quality Control Technologists and others. To facilitate this process, I developed a “Radiation Safety and Quality Control Standards, Policies, and Procedures Manual for the use of Diagnostic Radiological Equipment” which defines GVHS standards of performance for radiological equipment, policies, protocols and methods to meet those standards. The requirements in the GVHS Radiation Safety Manual are based on establishing compliance with Hospital, Canadian and International standards. Another aspect of this manual is to develop procedures for measuring the performance levels of Diagnostic Radiology imaging equipment and its relationship to image quality, radiation safety and compliance with provincial and federal regulations and laws.
Inspector of radiation health for the Environmental Health Division of the Bermuda Department of Health.
Sometime prior to 1978, the Department of Health had initiated a licensing system for users of radiating devices (x-rays and radioisotopes), which involved a licence fee, but little else. In the Island, the principal users of x-radiation were the Hospital and the dentists; together they employed some 60 x-ray units. The veterinary surgeons, police, the Maritime Museum and the TB and Cancer Association were other users. The airlines, HM Customs and Bermuda Post used x-ray scanners. Radioactive isotopes were used by the Hospital, Bermuda College (for teaching), the Biological Research Station (for research), the Tynes Bay incinerator, Esso and the Barrett bottling works (for measurement).
I therefore arbitrarily decided that the primary concern in dentistry was the radiation safety of the patient and of the operator. Acceptable entrance dose standards as a function of operating kVp did exist, as did maximum permissible values of leakage radiation. From the entrance dose values, it was obvious that very low kVp’s, low HVL’s, short focus-skin-distances and unnecessarily large and non-uniform x-ray beams should be avoided. If retakes and useless exposures were to be minimized, good resolution, high contrast, and adequate processing were a necessity. I wrote Licence Conditions for dentistry in 1996. They were accepted and distributed to all dentists early in 1997. The same year the testing program was designed to check the Licence conditions. They include mechanical stability and electrical safety of the unit. These were the dental unit parameters that I set out to examine, partly by measurement and partly by inspection. Environmental Health was very helpful in setting up the inspections, which took about 30 minutes of machine time for standard intra-oral units and an hour for more specialized dental units. From the outset the dentists were cooperative, and pleased that they were getting something for their licence fees.
After each inspection, I provided the Department with two copies of my report, one of which was sent to the dentist. Deficiencies were highlighted, and the Department expected them to be corrected. Some x-ray units were condemned, and replacement recommended. Unfortunately, the Department was slow in enforcing these recommendations in the past, and frequently the same deficiencies would appear on subsequent visits. Generally, however, the level of radiation health improved as a consequence of these inspections. The written licence conditions together with new testing procedures and phantoms, should improve the compliance. As regulations and guidelines are developed in other jurisdictions licence conditions are modified and the scope of these inspections is conformed.
The mammography unit x-ray units operated by the TB and Cancer were examined from the viewpoint of the Canadian Association of Radiologists Accreditation standards.
Bermuda Health Care Services had acquired a mammographic and an overhead table unit. Mammography unit were inspected on the same basis. Radiographic unit is tested for Accreditation standards as in the KEM Hospital.
The examination of veterinary units followed much the same principles. Proper safety measures were adopted in all three veterinary clinics based on the new Bermuda Veterinary Licence Conditions.
The other, highly specialized x-ray generators (Police bomb detection, Museum examination, Airline and Customs scanners) were examined from the point of view of operator safety only. Licence Conditions were developed and implemented to reflect this approach. Security aspects (image quality) of these units are not evaluated.
The inspection of isotope user sites concentrated on radiation safety (as evinced by good housekeeping practices and safe disposal). Recommendations were made for improvement where indicated. Where isotopes were used as measuring devices only, measurements of radiation fields in the environs were made to ensure personnel safety, and wipe tests were performed where indicated. Again, in 1997 new licence conditions were written and installations were tested accordingly.
In none of the radiation sites on the Island did personnel exposure levels reach those requiring routine personnel TLD monitoring. I did recommend this to the dentists on a number of occasions, primarily as a means of reassuring employed personnel. The X-ray Department of the Hospital used monitors provided on a contract basis from a US company.
During many visits, I accepted an invitation to give Radiation Seminars to all users to address the subject of radiation hygiene. This was very well received. On a later occasion I spoke to the Environmental Health inspectors on the subject of radiation health in general.
Quality assurance surveyor in the Medical Imaging Department of the King Edward VII Memorial Hospital, Bermuda
this function fulfilled a requirement for accreditation of the hospital in meeting American and Canadian standards
this function fulfilled a requirement for accreditation of the hospital in meeting American and Canadian standards
I came to Bermuda as replacement for the retired Medical Physicist, Dr. John MacDonald in 1994. The specifications for hospital accreditation required that the X-ray Department be examined at least biennially to ensure that its equipment and procedures met existing standards. In 1997 testing was designed according to new American College of Radiology standards.
During this period, the KEMH Medical Imaging Department had four major x-ray rooms, a CT suite, an overhead unit and a C-arm fluoroscopy unit in the OR suite, and three mobile units. In addition, it has a nuclear imaging suite with a gamma camera, an ultrasound suite, and, a mammography unit. Two of the x-ray rooms contained radiographic/fluoroscopic units, one contained a radiographic/tomographic unit, and the fourth a skull unit. During the period of my examinations, all x-ray generators were made by GE, as were most of the units. Service was supplied by GE in New York on service contract, and was generally prompt. Two automatic film processors were installed, and serviced by a local contractor. During my tenure, the one mobile unit, the C-arm, and the one radiographic/fluoroscopic unit were replaced.
The examinations of these units covered all aspects of radiation safety as well as those parameters which contribute to image quality. Over the period of these visits, instruments became available that made possible the on-site measurement of more and more x-ray parameters.
All radiographic and fluoroscopic equipment in Bermuda is monitored at least biannually to ensure that it is functioning properly. Although it is not possible to consider all possible variations of equipment performance to be monitored, adherence to this standard maximized image quality and assisted in reduction of patient doses. Key points to considered are: performance characteristics to be monitored, qualifications of personnel, follow-up procedures, and patient radiation exposure.
The goal of testing is to assist with the production of the highest quality diagnostic image at the lowest reasonable dose consistent with the clinical use of the equipment and the information requirement of the examination and to establish performance standards.
Member of the of The Center for Devices and Radiological Health , FDA, USA, advisory committees
I provided independent, professional expertise and technical assistance on the development, safety and effectiveness, and regulation of medical devices and electronic products that produce radiation. Each committee consists of experts with recognized expertise and judgment in a specific field. Members have the training and experience necessary to evaluate information objectively and to interpret its significance. See NEXT documents on testing in Radiography, Fluoroscopy, Dental and CT used by FDA, and which documents I helped to produce.