Thyroid cancer in childhood in Fukushima

It has been questioned if the irradiation the nuclear power plant accident has caused increased the number of thyroid cancer in the area. For the first few years, most researchers have observed no cause effect relationship between irradiation and the cancer occurence. They have attributed it to the screening effect. The cohort of the children in Fukushima has been examined with accurate ultrasound deviced so that, they say, it has found occult cancer which would stay inactive throughout their lives. Recenetly, however, a number of researchers have published papers contradictory to earlier studies. Quite a number of children have undergone partial or total thyroidectomy. It concerns the future of the children. It should be studied aggressively apart from the policy of nuclear power generation.  

The following article says they could eliminate the common, that is, background occurrence of childhood thyroid cancer in its research. It affirms the occurrence is proportionate to the external irradiation.  

I believe thyroid gland could be affected by mainly internal irradiation of I131 which is uptaken by the gland as a source of thyroxin. I wonder if, without evaluation of internal irradiation, they could conclude this way. They might speculate the internal irradiation could be proportionate to the external.

 https://pubmed.ncbi.nlm.nih.gov/39338045/

This article handles excessive absolute risk for childhood thyroid cancer based possibly on the calculated radiation dose of I131. So far as I know, I131 has not been directly measured by the authority for the first couple of weeks, which has been regarded as a big mistake for radiation protection. Anyway, they conclude the irradiation on children was the cause of occurence of thyroid cancer. It is against the overdiagnosis thesis or screening effect in the beginning of research in this field. 

https://pubmed.ncbi.nlm.nih.gov/37760552/