If
there is any new hardware technology that would be making major
inroads in our lives, it is the concept of 3D printing. Readers must
have seen printers associated with computers that employ ink jets. In
the printing action of these printers, the ink jets place extremely
small droplets of ink onto paper to create an image. These droplets
or dots when they dry up are extremely small, even smaller than the
diameter of a human hair (70 microns)! Secondly, the dots are
positioned very precisely, with resolutions of up to 1440 x720 dots
per inch (dpi). To the naked eye the dots are indistinguishable and
we see the whole page or picture.
This
simple 2D printing was extended to 3 D printing when a US company, 3D
Systems, Inc. invented and patented stereolithography (also known as
solid imaging) in mid-1980's. Those of you who are familiar with
conventional manufacturing processes would know that it consists of
processes by which an object is constructed by cutting (or
"machining") raw material into a desired shape. 3 D
printing works in exact opposite fashion. It is characterised as
"additive" manufacturing in which means a solid,
three-dimensional object is constructed by adding material in layers.
To understand this process, let us consider a simple 3 D printer that
is capable of creating plastic objects. Such printers incorporate a
bioplastic (plastics derived from renewable biomass sources ) wire or
filament mounted on a spool so that it can be easily drawn. When the
printer is told to print something, it pulls the bioplastic filament
through a tube and into an extruder, which heats it up and deposits
it through a small hole and onto the build plate. Just like like an
inkjet printer, the 3D printer too makes passes (much over the build
plate, depositing layer on top of layer of material to create the
finished product. This can take several hours or days depending on
the size and complexity of the object. The average 3D-printed layer
is approximately 100 microns or 0.1 millimeters. Throughout the
process, the different layers are automatically fused to create a
single three-dimensional object in a dots per inch (DPI) resolution.
People
have been manufacturing prototype plastic parts using such printers.
Recently, I have reported how an astronaut on International space
station got a specialized
wrench printed out on the space station itself from software
uploaded from earth. The technique is so easy to use that it opens up
limitless opportunities of creating new things very easily.
Mina
Khan is a 2 year old girl from London. A defect in her heart was
detected in the 26-week scan, during pregnancy, well before birth.
After she was born, she looked fine but had only a 50% chance of
living for which she needed breathing support. Mina was kept in the
hospital for three months during which period, the little girl was
sick a lot and did not put on weight. She hardly woke up and had to
be fed through a nasal tube. She was born with a hole between two
chambers of her heart. Doctors found her heart so much deformed that
they thought that it just could not be repaired. The two heart
chambers called ventricles are actually the two pumps that circulat
blood to the heart and the lungs. Because of the hole, she felt
constantly tired, sickly and unable to put on weight. Only possible
cure in her case was effective patching of this hole. However her
heart, she being just a two year old toddler, was so small that even
a top class paediatric heart specialist surgeon, would have found it
difficult, making the operation risky.
It was
here that Dr Gerald Greil, who has pioneered the use of the
3D-printing technique at St.Thomos Hospital in London, decided to try
something new and path breaking. Mina's heart was fully scanned by
Doctors in Manchester using magnetic resonance imaging (MRI) and
computerised tomography scans. Dr Greil segmented it out and got it
into format using special software suitable for printing.
In
United states a new technique has been developed to create practice
organs made from plastic from MRI scans of patients before actual
surgery can be performed. Using similar procedure, Dr. Greil created
an exact and precise copy of Mina's heart including its defect. The
surgeons were thus able to see inside of her heart and the hole as it
looked when the heart was pumping. This enabled them to exactly
design a bespoke patch that could be stitched to Mina's heart.
Professor
David Anderson, who led the operating team, agrees that Mina had a
'very complex' hole in her heart and her case was a huge intellectual
challenge. However, with the model, his team could go into the
operation with a much better idea of what they would find. The
operation turned out to be a success as Dr. David Anderson and his
team managed to tailor the Gore-Tex patch stitched into Mina's heart.
Mina's mother confirms that after the operation, Mina is eating for
herself, she is not breathless and turning into a normal little
girl.
Dr.
Greil's technique has certainly opened a new vista for such patients
where operating on them is considered too risky. This has been
possible only by use of 3D printing.
31st
January 2015
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