Major flaws in the LNT model 'logic'

 

What is the 'logic' behind the LNT model?

 

  • A small amount of radiation (low-dose radiation) would cause a small amount of DNA damage which can result in mutations.

  • Increased mutations imply increased transformations of normal cells to cancer cells, and so more cancers.  

  • Even a single ray of radiation can cause DNA damage.

  • Therefore there is no threshold dose for radiation-induced cancers.

 

This argument results in the linear no-threshold or the LNT model for radiation-induced cancers.

The Flaws in the LNT model 'logic'

 

  • DNA damage occurs even in the absence of low-dose radiation due to natural causes.

  • Low-dose radiation results in increased defenses known as adaptive protection (Feinendegen, 2013) consisting of antioxidants, DNA repair enzymes, apoptosis, etc. which would reduce the natural damage that would have occurred in the absence of the low-dose radiation.

  • Thus, there would be less overall DNA damage following low-dose radiation exposure, as seen in the graphs below. 

 

DNA damage does not increase linearly with dose at low doses.

 

 

 

Now let us consider whether increased mutations mean increased cancers.

Percentage of patients with cancerous mutations is relatively unchanged (for age range of 45 to 85) but cancer mortality rate increases drastically with age. Some factor, other than mutations, is causing these cancers. 

 

Mutations do not imply cancer, as seen in the above graphs.

LNT Model argument assumes increased mutations mean increased cancers.

 

Also, note that almost everyone has cancerous mutations, see (Greaves, 2014)but everyone does not have cancer.

 

Thus, the two basic arguments used in the LNT model, that low-dose radiation increases mutations linearly and that mutations increase the risk of cancer, are not supported by evidence.

 

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