Cc. The Hot Particle Problem It is important to recognize that the ICRP has given no guidance with respect to nonuniform irradiation of the luna by insoluble alpha-emitters such as insoluble plutonium particles. In its Publication 9, the ICRP states: ...In the meantime there is no clear evidence to show wheth-x», with a given mean absorbed dose, the bioloyical risk associated with a non-homogeneous distribution is greater or less than. the risk resulting from a more diffuse distribution of that dose in the lung. 29 In effect, the ICRP is saying that there is no guidance as to the risk for non-homoqgeneous exposure in the lung, hence the MPC, and the MPLB are meaningless particles. for insoluble plutonium af The NCRP offers the following and similar statement with respect to these particles: (210) The NCRP has arbitrarily used 10 percent of the «cleme of the ortan as the significant volume fer irradiation of the gonads. There are some cases in which choice of a significant volume or area is virtually meaningless. For example, if a single particle of radioactive material fixed in either lung or lymph node may be carcincegenic, the averaging of dose either over the lung or even over one cubic centimeter may have little to do with this case. 30 This hot particle problem is also well recognized in the biological community. The following is extracted from a 239/ ICRP Publication 9, Op. 30/ NCRP Report No. et ’ ; 4 Oe flee .- 4f ° 39, Got ve Leh we, cit., Op. cit., er er ae gy wh p. 4. pp. gM” 79-80. oe 2 Ory eras “a0 ot . a Bare ‘eM wy ~* ateg te a) Hees 1 2 tw fe EE. lg ag ee at A en . te, te a OPED euaa AE eg RSE RR OR De AD Si .ttey re OM : Takefae Set pte Me SONTE UB aa a ae mle we sy "hy a” ty. tea Ta re ae wr 4FT