Final answer:
Bone marrow dose is usually estimated from measurable doses like gonadal dose or ESE, not measured directly. The effective dose takes into account the sensitivity of various tissues to radiation with a weighted factor.
Step-by-step explanation:
The question pertains to the measurement of bone marrow dose in the context of radiation exposure. In the field of radiology and radiation protection, the subject is typically medical or health physics. Bone marrow dose is generally not measured directly due to the invasive nature of such a procedure; instead, it is estimated from other measurable doses such as gonadal dose or Entrance Skin Exposure (ESE), which is why options 1 and 4 are less common in practice. To understand how radiation affects the body, various calculations are used.
The effective dose calculation takes into account the sensitivity of various tissues to radiation. For example, bone marrow, which is sensitive to radiation, contributes to the effective dose calculation with a weighted factor. As shown in the effective dose formula, if 1 mSv is absorbed by the bone marrow, it contributes 0.012 mSv to the effective dose due to the tissue weighting factor and the assumption that only 10% of the radiation energy is absorbed by the marrow:
Effective dose =
0.04 X 1 mSv (thyroid) +
0.01 X 1 mSv (brain) +
0.01 X 1 mSv (salivary gland) +
0.12 x 1 mSv x 0.1 (bone marrow) +
0.01 X 1 mSv × 0.15 (skin)
= 0.07 millisieverts (mSv).
The concept of Radiation Weighting Factor (RBE or QF) is also crucial. It is used to convert Gray (Gy), a unit of absorbed dose, to Sievert (Sv), which is a unit that takes into account the biological effectiveness of the radiation. Therefore:
1 mSv = 1 mGy × RBE.
Understanding these concepts is important for calculating radiation doses and ensuring radiation safety.