How does a Superficial X-ray Therapy Machine work?

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There are many types of radiation therapy machines, each suited to a different purpose.  Some create radiation strong enough to go through an entire body, some barely penetrate deeper than the first few millimeters of skin.  The machines at Just Skin fall into the later category which can dramatically reduce side effects by minimising irradiation to healthy tissues. 

Producing this radiation safely and consistently requires many finely engineered parts working together.

How does a Superficial X-ray Therapy Machine work? 1
How does a Superficial X-ray Therapy Machine work? 2

Body of the Machine

It is often assumed that this bulky part is where the radiation is produced.  However, this part mainly contains cooling and electrical hardware.  High voltage is produced here by a special generator that multiplies the systems in-coming mains voltage by up to 435 times.  This voltage then travels along a special cable fitted in the grey tubing on the machine arm.  Coolant also flows through pipes in this tubing.  Producing radiation generates lots of heat, so a chiller very similar to a car radiator is used to dissipate the heat.

How does a Superficial X-ray Therapy Machine work? 3

Machine Arm 

This arm is used to move the treatment applicator to the desired location.  It can move in any direction and rotate vertically and horizontally.  This is necessary as treatment can be on any part of the body.

How does a Superficial X-ray Therapy Machine work? 4

Gantry Head

Radiation is produced in the gantry head by an X-Ray tube, the radiation is directed towards the treatment applicator.  A high voltage, up to 100,000 Volts, is applied across a Tungsten filament and a Tungsten block called the target.  The negatively charged filament releases electrons which are attracted to the positively charged target.  Due to the high voltage, these electrons are moving extremely fast and impact the target with high energy.  This interaction is what produces the ionising radiation through a process called bremsstrahlung.  The radiation is in the form of photons up to a maximum energy of 100,000 Volts.  Depending on the treatment type the maximum photon energy may be as low as 10,000V.  The treatment is typically quoted in terms of kiloVolts with the most common treatment being 50kV or 80kV.

How does a Superficial X-ray Therapy Machine work? 5


Radiation produced in the X-Ray Tube is released in all angles.  Therefore the X-Ray Tube contains thick lead shielding all around it to block the radiation from going in unwanted directions.  It is only permitted to leave through the filtered opening toward the treatment applicator.  An aluminum and/or copper filter is placed in the way of the beam to filter out unwanted low energy and scattered radiation to make sure the strength of the radiation is just right.  This filter is typically between 0.02 mm and 2 mm at Just Skin sites.

How does a Superficial X-ray Therapy Machine work? 6


The applicator is a stainless steel cone with a clear lucite viewing tip that confines the radiation beam to the specific treatment area.  Some people require treatment of very large areas, for these Just Skin has applicators up to 18 cm in diameter.  For smaller treatment areas, applicators down to a diameter of 2cm can be used.

How does a Superficial X-ray Therapy Machine work? 7

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