Junior Fellows Symposium, ISMRM 2020.
Methods, sources and data from the talk.
OECD data does not include all countries (particularly India and China)
World bank population data
So, this dataset is incomplete, but from this:
- we can use the USA's number as a rough guide. From [source], the US forms ~20% of the global market (a 2019 market size of $1.5/5B for [1, grandviewresearch] North America / [2, fortunebusinessinsights] global ), thus taking the last ten years (2009-2018) we can estimate a rate of 350 scanners per year sold in the US, and thus a global rate of 1750 scanners per year. (From the data table, for the countries listed, gives ~1250 scanners/year)
Just for more estimates, Magnetic-resonance.org estimate 5000/year!
- we can fit a growth rate of 5.6%, which is similar to [1] and [2]'s estimates of 5% growth.
20% of the world's helium supply is used for MRI (30% in USA, 12 million m^3).
The sustainability of helium supplies fluctuates a lot! Seemingly people (or.. one person who does a lot of interviews) are less worried now. Essentially, the US produces enough helium for its own use and export from its natural gas extraction, and other sources world wide are assumed to be sufficient. The main issue is that limited suppliers can cause price instability and limited availability .
The Federal Reserve, operated by the US Bureau of Land Management (#BLM), used to stockpile Helium, but has been selling off its reserves as its no longer considered necessary to store (and is non-trivial) and can produce enough for its short term domestic supply. The USA produces a lot of Helium from natural gas extraction. The Federal Reserve did supply approximately 42% of the US's demand and 35% of global demand of crude Helium (2013, https://www.doi.gov/ocl/hearings/113/americasheliumsupply_071113 ).
More sources of Helium globally are expected from Qatar, Algeria and Russia - though there may be still be fluctuations in global prices as these are being developed.
Estimated world supply:
31.3 billion m^3 (r.o.w.) + 3.9 billion m^3 (u.s.a.)
USGS Helium Report So.. if the US is ~1/5 of the global MRI users.. and so global MRI Helium usage is ~(12*5=) 60 m^3/year... so ~36 b/60 m = 600 years... 200 if 1/3 of Helium usage is MRI.. I think we are good?
Party balloons are ~10% of Helium use ; D
MRI main field Magnets:
J. Overweg MRI main field magnets. ISMRM, 2006.
A lecture from ISMRM also includes the Biot-Savart eq for estimating windings:
NumWindings = Field(T)*Radius(m)*2/mu_0(T.m/A)*I(A)
For a Radius of 0.6m, a current of 300A and mu_0 given by 1.256637E-6 T.m/A:
Low-cost and portable MRI:
LL. Wald, et al. Low‐cost and portable MRI. JMRI, 2019.
Energy efficiency:
COCIR - Magnetic Resonance Equipment (MRI) - Study on the potential for environmental improvement by the aspect of energy efficiency (2012)
Some heavy approximations, see methods below. Esimating travel to the last two year's ISMRM conference, and the prospective conference in Sydney.
Numbers taken from 2018 Plenary lecture, percentage region memberships estimated from charts in lecture. Region "central" locations have been included on the graphs. CO2 emissions aviation = 328g/per person per km (estimated from British Airways CO2e report). Inter-location distances as determined by https://www.freemaptools.com/how-far-is-it-between.htm (beware the clickbait) and choosing a central location for each region: