The technique is only applicable to radioactive material that emit gamma rays, although in certain circumstances, beta emitters can be measured also. Disadvantages of whole body counting are that it can only be used for gamma emitters, except in special circumstances, and it can misinterpret external contamination as an internal contamination. source
WBC DOES NOT DETECT ALPHA AND BETA INTERNAL CONTAMINATION. THE SPECIFICITY FOR INTERNAL GAMMA CONTAMINATION DETECTION IS ALSO QUITE QUESTIONABLE.
From 8~10/2011, Minami soma in Fukushima conducted WBC for the citizens.
2,884 people had the WBC check in total.
Until September, they used 2 WBC facilities from Tottori prefecture, and they measured Cs-137 only from 6 people. However, once they started using WBC from USA in September, 274 people were told positive for Cs-137.
6 → 274
Their excuse is that it was because the minimum measurable dose of US facility is lower than Japanese ones.
(Source)
(Note from Nika)
The wiki states, regarding WBC scanners:
The reason that these instruments are so sensitive is that they are often housed in low background counting chambers. Typically this is a small room with very thick walls made of low-background steel (~20 cm) and perhaps lined with a thin layer of lead (~1 cm). The background reduction inside the chamber will be several orders of magnitude. source
Its a well know fact that some radiation detection systems (like geiger counters) can become “saturated” and desensitized when exposed to higher levels of radiation.
If these WBC scanners in Minami soma are not installed in specially shielded rooms and if those rooms are not aggressively sanitized of tracked-in radioactive contamination then its likely that the device is not functioning properly. If the agency using the device has a vested interest in NOT detecting contamination then saturated desensitized WBC machines are in their best interests and not in the best interest of the Japanese people nor the world.