The first succesful tratement of a head and neck patient, with radiation, was actually done in the late 1800's at the Madame Curie Institute in France. Up until the 60's radiation was performed in much the same way, typically using a radiative source, such as cobalt 60, in a lead box. Eventually, they would move several bricks of lead sitting on top of the box to give them the correct radiation field (they call it primary collimation). In the 1960's the Medical Linear Accelerator (LINAC) replaced cobalt 60 as the radioactive source and was electronic, ionizing radiation that is generated when intense (4-MeV to 20 MeV) microwave energy is directed into a water cooled target made of tungsten and converted into ionizing radiation. The old cobalt machines (which are still used in some parts of the world), had to have the treatment times increased as the radioactive source decayed. This would result in sometimes, horrific and irreparable skin damage. The LINAC all but eliminated that, they also discovered that by bending the beam, they could further eliminate much of the "dark radiation" responsible for skin damage, and many patients, like myself, suffer only a mere sunburn. Many elements haven't changed since the beginning. They still use the bricks for primary collimation (automated and under computer control of course and made of pure tungsten) and they still use beam blockers and shadow trays to protect radiation sensitive areas (mainly for XRT patients) much as you described in the 1939 article. They also developed a number of "applicators" which also act as secondary collimation to further define the radiation field. They now typically use a tray and the devices are not physically placed on the patient. They moved away from lead and have this material that's eutectic (melting) point is so low that is becomes liquid in hot water, so they can reuse it over and over. The latest advance in RT is PBT (AKA photon beam therapy) which uses a "charged particle" concept). Less than 1/2 dozen facilities in the US have access to this technology. MD Anderson stated last year that they were investing 200 million dollars in a dedicated facility for it. It is quite different from ionizing radiation in that the charged particle doesn't develop it's full potential until it reachs the actual target, making collateral damage virtually zero. I believe that the treatment is done in one shot as well, fractionalization is not required. I have also read that it is so accurate that they supplement it with IMRT to guarantee clean margins (although probably not the same amout as used as the primary treament) . PBT is a huge investment. The typical LINAC is probably 1 or 2 million dollars and weighs in around 9 tons. PBT has 35 tons of just the gantry in each treatment suite. The PB generator can be "piped" to multiple treatment rooms, cutting the cost somewhat, perhaps the higher patient throughput is a cost factor as well. It requires an entire custom, dedicated building as well.
In the early 1900's people were encouraged to drink radium laced water as as a "health booster" and cure all. An unshielded x-ray machine for measuring your foot size, for use in shoe stores, exposing the sales people to phenomenal amounts of radiation, hence the Food, Drug and Cosmetic Act was enacted in 1938. The CDRH was once called Radiological Health Unit. For an FDA timeline see:
http://www.fda.gov/cdrh/centennial/milestones.html Understand also that radiation doesn't "fry" or "burn" the tumor, rather it alters the DNA and cancer can't reproduce itself and dies off (literally shrivels and melts - at least that's what supposed to happen anyway). Normal cell tisses will regenerate to a large degree but they they found that they have to allow time for healthy tissues to heal so that's why the dose is split up into fractions. The first big technological leap was going from Cobalt to Ionizong radiation and I believe the next one will be once PBT once it is more accessible.