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Cancer treatment by UV radiation from nanoparticles in X-ray heated surroundings
X-rays absorbed in surroundings heat gold nanoparticles to produce UV radiation that damages DNA to destroy cancer cells by blocking reproduction
The LEM predicts the biological effects of X-ray radiation dose supplied to a local region of cells or tissues. LEM stands for local effective model. The LEM is based on the concept the biological effect of the local dose is independent of the radiation quality, i.e., equal doses of 20 and 50 keV X-rays should produce the same biological effect.
Recently, gold NPs adjacent cancer tumors are found to enhance necrosis by taking advantage of the increased absorption of gold compared to soft tissue. NPs stand for nanoparticles having dimensions < 100 nm. However, the high absorptivity of gold is of little consequence as little if any X-rays are absorbed in the nanoscale NPs. Indeed, X-ray absorption of gold NPs in water is shown  to be negligible and almost totally dominated by the far larger dimensions of the water surroundings.
What this means is X-ray absorption in gold NPs is not the cause of cancer necrosis, but rather necrosis is somehow caused by the heating of NPs from the X-rays absorbed in the surrounding water perhaps explaining the current discrepancy in the LEM between X-ray doses and observed cancer cell necrosis,
But how do NPs heated from water surroundings alone induce cancer tumor necrosis?
Currently, NP temperatures are of great controversy. Absorption cross sections at the incident power levels typical of RF-GHZ experiments  show increases in temperature cannot occur in NPs. In contrast, simulations  based on classical physics have claimed temperature changes of 30 – 40 °C occur consistent with liver cancer cell experiments after targeting those cells with gold NPs and exposure to RF fields, but QM governs the nanoscale. QM stands for quantum mechanics.
QM given by the Planck law precludes any increase in NP temperature because the heat capacity of the NP atoms vanishes as the high surface-to-volume ratios of NPs confine the heat from the surroundings to the NP surfaces. EM stands for electromagnetic. Instead, QED momentarily creates EM radiation having half-wavelength λ/2 = d standing across the diameter d of the NP. QED stands for quantum electrodynamics, but is a simple form of the complex light-matter interaction proposed by Feynman and others.
Since the standing EM radiation is created from the NP surface heat, the EM radiation propagates into the surroundings once the surface heat vanishes. The QED radiation has Planck energy E = hν in the UV and beyond that damages the DNA halting the growth of the cancer cells by precluding reproduction. Here, h is Planck's constant and ν is frequency, ν = (c/n)/λ = c/2nd, where c is the velocity of light and n the refractive index of the NP. See diverse QED applications at http://www.nanoqed.org/
Given that cancer necrosis may only occur as gold NPs are heated upon absorption of X-rays in surrounding water while DNA damage is usually thought to occur at UV levels from 3 to 8 eV, the Planck energy E of the QED radiation for gold NP having index n = 1.5 and diameters d from 1 to 100 nm is plotted in the thumbnail. The UV-C level of 254 nm having Planck energy E = 4.88 eV in 85 nm gold NPs is noted corresponding to the formation of the pyrimidine dimers that block DNA replication in all living systems.
The thumbnail shows QED produces X-rays in NPs < 1 nm, But even the 85 nm NPs may produce X-rays, i.e., QED radiation charges all NPs positive as electrons are lost by the photoelectric effect. Coulomb repulsion between positive charged NP atoms then fragments the NP into smaller and smaller fragments with increasing EM emission frequencies until the fragments < 1 nm are formed whereby even X-rays are produced.
QED radiation in producing X-ray emission from NPs is far simpler than the extremely unlikely process of 6 photon combinations  of 800 nm laser radiation of 10-100 nm gold NPs to explain X-ray emission to 15 keV.
Classical physics as the traditional method for estimating NP temperatures under X-ray radiation are not valid. QM governs the nanoscale.
QM requires the heat capacity of atoms in NPs vanish denying conservation of heat from X-ray induced heating of the surrounding water by an increase in temperature.
Instead, QED conserves the heat from X-ray induced heat in the surrounding water bt creating EM radiation inside the NPs instead of increasing their temperatures. However, the EM radiation charges the atoms by removing electrons which induces Coulomb repulsion between all atoms forming a state of hydrostatic tension that fractures the NPs. Subsequently, the heated fragments fracture to produce even progressively higher frequency EM emission. Hence, the gold NPs generate their own source of X-rays. Multi-photon processes are extremely unlikely.
The LEM should be updated for the biologically significant UV emission from X-ray absorption in the water surrounding NPs
 R. Kunzel, et al., "Evaluation of the X-Ray Absorption by Gold Nanoparticles Solutions," ISRN Nanotechnology, Volume 2013, Article ID 865283.
 G. W. Hanson, et al., "Electromagnetic absorption mechanisms in metal nanospheres:
 R. R. Letfullin, et al., "Absorption efficiency and heating kinetics of nanoparticles in the RF range for selective nanotherapy of cancer ," Nanomedicine:
 F. C. Masim, er al., "Au Nanoplasma as Efficient Hard X‑ray Emission Source," ACS Photonics, 3, 2184−2190, 2016.