Image Processing Reference
In-Depth Information
Figure4.8 Nelson x-ray power supply. (CourtesyofAmericanCollegeofRadiology)
Before public awareness brought legislation and regulations to control x-ray
apparatuses, the systems were fairly common and were often operated by untrained
workers. The infamous Tricho machine was used in beauty salons to remove
unwanted hair from women. Many Tricho patients suffered permanent injury
(including ulceration, carcinoma and death) from x-ray exposure, injury that
sometimes did not present symptoms for many years. Another well-known
unregulated x-ray device is the shoe-fitting fluoroscope used in many shoe stores
all over America until the 1950s. Some of these machines were still in use until the
1970s and 80s, their owners apparently unaware of federal regulations prohibiting
them. These machines would show the shoe salesman and the customer the relative
position of the bones of the foot inside the shoe. Many people would play with the
machines and subject their feet to extended doses of x rays. An example of such a
machine is shown in Fig. 4.9.
There are several viewing ports to enable the shoe salesman and the customer to
see the fluoroscope screen simultaneously. On one model called the Foot-O-Scope,
there were three different buttons for men, women and children, but all gave the
same intensity of x rays! Figure 4.10 shows an early radiograph of a foot inside a
shoe. Note the many nails in the heel of the shoe.
The “x-ray craze” happened as it did because there are few technical challenges
to making x-ray images. The only implements needed to make live x-ray images are
a Crookes tube, a high-voltage power supply, and a phosphor-coated glass screen.
Objects placed between the Crookes tube and the screen cast an x-ray shadow
onto the phosphor, which converts the x rays striking it into a visible green glow.
These components are relatively easy to make, and many amateurs have built x-
ray sources this way, although this is no longer a very popular activity because of
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