Technical Notes (English)
Medical Imaging Equipment by Province and Facility, 2012Equipment Type Definitions
Angiography Unit: A technology that enables blood vessels to show up on X-rays. A dense
contrast agent (X-ray dye) is injected into the blood vessel and an X-ray is taken. This
outlines the blood vessel, revealing blockages or other abnormalities.
Cardiac Catheterization Unit : A device used to image the blood vessels in
the heart, to examine the function of the heart and to dilate narrowed blood vessels that
are not supplying adequate amounts of blood to heart muscles; a form of angiography.
Computed Tomography (CT): A diagnostic technique that uses X-rays and computer technology to producecross-sectional images of the body (often called slices), both horizontally and vertically. CT scans can show detailed images of various parts of the body, including bones, muscles, fat and organs. They are more detailed than general X-rays.
Magnetic Resonance Imaging (MRI): A diagnostic technology that uses a large magnet, radio waves and a computer to scan a patient’s body and produce two- or three-dimensional images of tissues and organs.
Positron Emission Tomography (PET): A type of nuclear medicine that measures the metabolic activity of cells when a radioactive substance produced by a cyclotron is injected into a patient.
Gamma Camera (Gamma)—Nuclear Medicine: A device used in nuclear medicine to scan patients who have been injected with small amounts of radioactive materials.
Single Photon Emission Computed Tomography (SPECT)—Nuclear Medicine: A type of nuclear medicine thatmeasures the concentration of radio nuclides introduced into a patient’s body. One or more gamma cameras rotate around the patient and take pictures from many angles; a computer then uses the pictures to form a tomographic (cross-sectional) image.
Fusion Technology—PET/CT: Fusion technology that combines functional and anatomical imaging from PET and CT in the same display.
Fusion Technology—SPECT/CT: Fusion technology that combines functional and anatomical imaging from SPECT and CT in the same display.
Other Terms
Hospital: An institution where patients are accommodated on the basis of medical need and are provided with continuing medical care and supporting diagnostic and therapeutic services. Hospitals are licensed or approved as hospitals by a provincial/territorial government or are operated by the Government of Canada. Included are those providing acute care, extended and chronic care, rehabilitation and convalescent care, and psychiatric care.
Clinic (or Free-Standing Imaging Facility): Ranges from specialized services run privately by physicians, radiologists, dentists, chiropractors or mammography programs to broad-based imaging centres offering a wide range of tests.
Basic information on the National Survey of Selected Medical Imaging Equipment is provided below.
What’s Included: CIHI’s surveys from 2003 to 2007 and 2009 to 2012 (only the 2012 survey data is shown in Quick Stats) tracked data on medical imaging equipment that was installed and operational in Canadian hospitals and free-standing imaging facilities (sometimes also called non-hospital, community-based and/or private facilities) as of January 1 of each year. The 2012 survey collected information for CT scanners, MRI scanners, nuclear medicine cameras (gamma and SPECT), PET scanners, PET/CT scanners and SPECT/CT scanners, as well as for equipment used to perform angiograms and cardiac catheterization, bone densitometers and lithotripters (therapeutic devices). Note that information for the last two devices is not reported in any Medical Imaging in Canada release because either there is incomplete coverage or it is not applicable.
History: Over a period of many years, the Canadian Agency for Drugs and Technologies in Health (CADTH), formerly the Canadian Coordinating Office for Health Technology Assessment (CCOHTA), conducted a survey on the number, distribution and key characteristics of selected imaging technologies in Canadian hospitals. Following discussions with CCOHTA, CIHI undertook a similar survey in 2003 and conducted the survey annually thereafter, except in 2008.
The imaging equipment covered by the 2003, 2004 and 2005 surveys (angiography units, cardiac catheterization units, CT scanners, MRI scanners, nuclear medicine cameras and PET scanners) was the same as that surveyed by CCOHTA in 2001. From 2006, two types of fusion technology were included as well: PET/CT scanners, which have been installed in Canada since 2002 and combine functional and anatomical imaging from PET and CT in the same display; and SPECT/CT scanners, which were introduced in Canada in 2005. Bone densitometers were included in the surveys starting in 2006 as well. Per CIHI’s announcement to its stakeholders this summer, the 2012 National Survey of Selected Medical Imaging Equipment will be the last one carried out by CIHI.
Survey Process: CIHI retained the services of ProMed Associates Ltd., a medical imaging consulting firm, to coordinate data collection. ProMed contacted health regions, hospitals and relevant free-standing imaging facilities across Canada. Various organizations of health care professionals and provincial/territorial ministries of health were asked to promote participation in the survey. Respondents completed the online survey using a bilingual website. To maximize response rates, ProMed completed several rounds of follow-up with respondents.
Validating the Results: To ensure that the coverage was as complete as possible, responses were cross-checked against results from previous surveys, published lists of equipment (such as research reports and health directories) and data reported by hospitals and health regions to CIHI’s Canadian MIS Database (CMDB). Provincial/territorial ministries of health were also asked to validate overall equipment counts. In addition, ProMed reviewed information submitted and contacted participants for follow-up where required.
Technical Notes:
· The numbers of MRI and CT scanners in free-standing imaging facilities were imputed for years prior to 2003 based on data on years of installation collected in the 2003 National Survey of Selected Medical Imaging Equipment.
· Age of equipment is calculated from the year the equipment was installed and in operation to January 1 of the current survey year.
· Although the focus is on scanners used for clinical purposes, some scanners are also used either exclusively or partly for research.
Imputation of Exams
Exams from CT and MRI scanners that were not reported in the 2012 survey were imputed according to the method below:
Option A: For exams reported in the CMDB for the current year:
1. If the number of exams reported in the CMDB was within 10% (plus or minus) of the number of exams reported in the survey in the previous year, use CMDB numbers.
2. If there was more than a 10% difference (plus or minus) in the number of exams reported in the CMDB compared with the number of exams reported in the survey in the previous year, use the number from the previous year’s survey.
Option B: For exams not reported in the CMDB for the current year but reported in the survey in the previous year by the facility:
1. If the facility had the same number of pieces of equipment, use the previous year’s figure, adjusted for the number of hours of operation, if available (using correlation between additional hours of operation and additional number of exams, if possible).
2. If the facility had an additional piece of equipment, assume that this additional piece of equipment was in operation half of the time and produced the same average number of exams as the scanners in the facility, then add the extra exams to the previous year’s figure.
Option C: For exams not reported in the CMDB for the current year and not reported in the survey in the previous two years by the facility:
1. Within the jurisdiction and the setting (free-standing versus hospital), compute the average number of exams per scanner for all the facilities.
2. Apply this average to each facility that had a scanner but did not report exams.
a. If the scanner was installed prior to the current year, apply the full average.
b. If the scanner was installed within the current year, assume it was in operation half of the time and apply half of the average.
c. When, for a given jurisdiction and setting, exams were not reported by any facility, apply the Canadian average number of exams per scanner for the setting.
Notes:
· For Quebec, Option A does not exist because this province does not report to the CMDB.
· For non-reporting cancer care facilities, the number of exams is first imputed according to Option A and Option B. If exams are not reported in the CMDB for the current year and were not reported in the survey in the previous two years, compute the average number of exams per scanner for all cancer care facilities within the jurisdiction. If no other cancer care facility is available, apply the Canadian average of all cancer care facilities.
Calculation of Exams
Total Number of Exams: Exams from all scanners are included, including those used exclusively for research (this is consistent with the 2009 data release but different from the method used in CIHI’s report Medical Imaging in Canada, 2007, where exams from scanners with less than 50% clinical use were excluded from the total number of exams). The rationale for the change is that scanners used for research produce exams in the context of clinical trials; thus, excluding them would result in an underestimate of the total number of exams.
Number of Exams per Scanner: In the numerator, include the exams from all scanners for which exams were reported, including exams from scanners used exclusively for research. In the denominator, have a weighted count of scanners for which exams were reported (for example, a scanner used 60% of the time for clinical use would be 0.6 scanners). This approach avoids an underestimate of this indicator, since scanners used mainly for research produce fewer exams and should have less weight. This method is consistent with the 2009 data release but not with other previous releases.
Historical Revisions: The number of MRI exams in 2010–2011 was revised for Nova Scotia and Alberta. The number of CT exams in 2010–2011 was revised for Newfoundland and Labrador, Prince Edward Island, Nova Scotia, Manitoba, Saskatchewan, Alberta and the Northwest Territories.