This standard recommends the conversion coefficients between physical quantities such as free air kerma and fluence and protection and practical quantities in photon external radiation protection. This standard is applicable to adults exposed to (0.01-10) MeV photons. This standard is not applicable to local exposure and accidental exposure that may cause deterministic effects. GBZ/T 144-2002 Dose conversion coefficients for photon external radiation protection GBZ/T144-2002 standard download decompression password: www.bzxz.net

ICS13.100
National occupational health standard of the People's Republic of China GBZ/T144-2002
Dose conversion coefficients for use inradiological protection against photon external radiationIssued on April 8, 2002
Ministry of Health of the People's Republic of China
Implementation on June 1, 2002
Normative referenced documents
Terms and definitions
Application of practical quantities in monitoring of photon external radiation protectionConversion coefficients between physical quantities of photon radiation field
Conversion coefficients between free air kerma Ka, photon fluence Φ and practical quantitiesFree air kerma K. Conversion coefficients between practical quantities and protective quantities Appendix A (normative appendix) Conversion coefficients between monoenergetic photon free air kerma K, photon fluence Φ and exposure X
Appendix B (normative appendix) Conversion coefficients between photon free air kerma Ka, photon fluence Φ and exposure to ambient dose equivalent H*(10) and directional dose equivalent H(0.07,0) Appendix C (normative appendix) Conversion coefficients between monoenergetic photon free air kerma K. and personal dose equivalent Hp(10,0) and Hp(0.07,0) of ICRU plate and angle dependence coefficient Appendix D (normative appendix) Conversion coefficients between monoenergetic photon free air kerma K. and organ dose D and effective dose E
This standard is formulated in accordance with the Law of the People's Republic of China on the Prevention and Control of Occupational Diseases. If the original standard GB11712-89 is inconsistent with this standard, this standard shall prevail.
This standard, on the basis of retaining and enriching the applicable parts of the original standard GB11712-89, adopts the data of the International Commission on Radiological Protection (ICRP) Publication No. 74 (ICRP, 1996) and the International Commission on Radiation Units and Measurements (ICRU) Report No. 47 (ICRU, 1992) and No. 57 (ICRU, 1998), updates and supplements the original standard data, and provides the conversion coefficients between radiation field quantity and protection quantity, and radiation field quantity and practical quantity for photon external exposure protection. In order to be consistent with the terminology in ICRP Report No. 74 and ICRU Report No. 57, the name of this standard is changed to "Dose Conversion Factors for Photon External Exposure Radiation Protection". This standard quotes the reference radiation conditions specified in GB/T12162-90 "X, Y Reference Radiation for Calibration of Dose Meters and Dose Rate Meters and Determination of Their Energy Response". Appendices A, B, C and D of this standard are all normative appendices. This standard is proposed and managed by the Ministry of Health.
The drafting unit of this standard: Institute of Radiation Medicine, Academy of Military Medical Sciences. The main drafters of this standard: Yang Guoshan, Guo Yong, Xie Xiangdong, Cai Fangong, Zhou Hongmei, Zhou Kaixin. The Ministry of Health is responsible for interpreting this standard.
1 Scope
Dose conversion coefficients for external photon radiation
GBZ/T144-2002Www.bzxZ.net
This standard recommends the conversion coefficients between physical quantities such as free air kerma and fluence and protective quantities and practical quantities in external photon radiation protection.
This standard is applicable to adults exposed to external photon radiation of (0.01~10) MeV. This standard is not applicable to local exposure and accidental exposure that may cause deterministic effects. 2 Normative references
The clauses in the following documents become the clauses of this standard through reference in this standard. For any dated referenced document, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties reaching an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version applies to this standard.
GB12162 X, Y reference radiation used to calibrate dosimeters and dose rate meters and determine their energy response 3 Terms and definitions
The following terms and definitions apply to this standard
Photon fluence Φphotonfluence
The quotient obtained by dividing dN by da:
P=dN/da
Where: dN——the number of photons incident on a sphere with a cross-sectional area of ​​da. Unit: m23.2
weakly penetrating radiation and strongly penetrating radiation
If the ratio of the skin equivalent dose or eye lens equivalent dose produced by the radiation to its corresponding limit is greater than the ratio of the effective dose produced by the radiation to its corresponding limit, then this radiation is called weakly penetrating radiation: if the ratio of the effective dose produced by the radiation to its corresponding limit is greater than the ratio of the skin equivalent dose or eye lens equivalent dose produced by the radiation to its corresponding limit, then this radiation is called strongly penetrating radiation. 3.3
kerma
dE, divided by dm to obtain the quotient:
K=dE.r/dm
Where: dE-the sum of the initial kinetic energies of all charged ionized particles released by uncharged ionized particles in a substance with a mass of dm. Unit: J·kg\; Special name: Gy. Free air kerma K. Refers to the kerma released in free air. 3.4
ICRU sphereICRU sphere
A tissue equivalent sphere with a diameter of 30cm and a density of 1gcm, the elemental composition by mass is O: 76.2%, H: 10.1%, C: 11.1%, N: 2.6%.
ICRU plateICRUslab
A tissue equivalent plate with a size of 30cmX30cm×15cm and a density of 1gcm, the elemental composition is the same as defined in 3.4. 3.6
protection quantityradiationprotectionquantityThe dosimetric quantity in the human body specified by the International Commission on Radiological Protection (ICRP), the protection quantity includes organ dose, organ equivalent dose and effective dose.
operationalquantity
The quantity proposed by the International Commission on Radiation Units and Measurements (ICRU) that can be measured by monitoring instruments in radiation protection practice and can be used as a reasonable approximation of the protection quantity (neither underestimated nor overestimated). Practical quantities include ambient dose equivalent, directional dose equivalent and personal dose equivalent.
Expanded fieldexpandedfield
A hypothetical radiation field derived from the actual radiation field. In the entire relevant volume, the photon fluence and its angular distribution and energy distribution are the same as the actual radiation field at the reference point. 3.9
Expanded and aligned fieldexpandedandalignedfieldA hypothetical radiation field derived from the actual radiation field. In the entire relevant volume, the photon fluence and its energy distribution are the same as the actual radiation field at the reference point, but the photon fluence is unidirectional. 3.10
Dose equivalent Hdoseequivalent
The dose equivalent H at a point in the tissue is the product of D and O, that is, H=Do
Where: D is the absorbed dose at the point;
Q is the quality factor of the radiation.
Unit: J·kg: Special name: Sv.
Ambient dose equivalent H*(d)ambientdoseequivalent corresponds to the dose equivalent generated by the extended directional field at the measurement point at the depth d on the radius of the inverse extended directional field in the ICRU sphere. For strong penetrating radiation, d=10mm is recommended, and H*(d) is recorded as H*(10). For weak penetrating radiation, d=0.07mm is recommended. Unit: J·kg; Special name: Sv.
Directional dose equivalent H(d, 2)directionaldoseequivalent corresponds to the dose equivalent generated by the extended field at the measurement point at the depth d on the radius of the specified direction 2 in the ICRU sphere. For weak penetrating radiation, d=0.07mm is recommended, and H(d, 2) is recorded as H(0.07, 2). For strong penetrating radiation, d-10mm is recommended. Unit: J·kg; Special name: Sv.
Personal dose equivalent H (d) individualdoseequivalent The dose equivalent in the soft tissue at an appropriate depth d below a specified point on the human body. For strong penetrating radiation, d=10mm is recommended; for weak penetrating radiation, d=0.07mm is recommended. Unit: J·kg: Special name: Sv3.14
Anthropomorphic models Anthropomorphic models are mathematical models of the human body used to calculate the absorbed dose distribution of the human body, that is, human tissues or organs represented by mathematical formulas. 3.15
Irradiation geometries indicate the orientation of the incident radiation beam relative to the body or phantom. In this standard, the irradiation geometries from front to back, from back to front, from the side (including the left and right sides) and rotational irradiation all refer to unidirectional wide beam photons, that is, plane parallel photon beams, when irradiating, the photon beam is perpendicular to the long axis of the body or anthropomorphic phantom. Isotropic irradiation geometry means that the photon flux per unit solid angle in the radiation field is independent of direction. Various irradiation geometric conditions are represented by the following symbols: AP - irradiation from front to back;
PA - irradiation from back to front:
LAT - irradiation from the side;
RLAT - irradiation from the right side:
LLAT - irradiation from the left side:
Rotational irradiation:
Isotropic irradiation.
Application of practical quantities in monitoring of external photon radiation protection 4
4.1 Ambient dose equivalent H*(d) and directional dose equivalent H(d, 2) H*(d) and H(d, 2) are practical quantities used in environmental and site monitoring, among which a) H*(10) and H(10, 2) are applicable to strong penetrating radiation. The H*(10) value at a certain point in space can be used as an approximate value of the effective dose received by a human body at that point: The H(10.2) value at a certain point in space can be used as an approximate value of the effective dose received by a human body at that point when it is irradiated in two directions. b) H(0.07,2) and H*(0.07) are applicable to weak penetrating radiation. In a unidirectional radiation field, H*(0.07) is equal to H(0.070°). The H(0.07.2) value at a certain point in space can be used as an approximate value of the skin equivalent dose received by a human body at that point when it is irradiated in two directions.
4.2 Personal dose equivalent H(d)
Hp(d) is a practical quantity used in personal monitoring, where a) H,(10) is applicable to strong penetrating radiation. The Hp(10) value can be used as an approximate value of the effective dose received by the torso. b) H,(0.07) is applicable to weak penetrating radiation. The H,(0.07) value can be used as an approximate value of the equivalent dose received by the skin near the dosimeter.
5 Conversion coefficients between physical quantities of photon radiation field 3
Appendix A (normative appendix) gives the mathematical relationship and conversion coefficients between physical quantities such as monoenergetic photon free air kerma K., photon fluence Φ and irradiation dose X 6 Conversion coefficients between free air kerma K, photon fluence Φ and practical quantities 6.1 Conversion coefficients between free air kerma K and photon fluence Φ and practical quantities are used for the development, evaluation and calibration of photon monitoring instruments.
6.2 Appendix B (Normative Appendix) gives a) the calculation formula and conversion coefficients from monoenergetic photon fluence @, free air kerma K. and exposure X to ambient dose equivalent H*(10) and directional dose equivalent H(0.07, 0°); b) the conversion coefficients from free air kerma K. and exposure X to ambient dose equivalent H*(10) and directional dose equivalent H(0.07, 0°) under the filtered X-ray reference radiation conditions specified in GB12162; c) the conversion coefficients and angle dependence coefficients from free air kerma K. to directional dose equivalent H(10, 0°) and H(0.07, 0°).
6.3 Appendix C (Normative Appendix) gives the conversion coefficients and angle dependence coefficients from free air kerma K. to personal dose equivalent H(10, 0°) and Hp(0.07, 0°) using ICRU flat plate as phantom. 7 Conversion coefficient between free air kerma K and protection amount 7.1 The conversion coefficient between protection amount and free air kerma K is used for calculation of effective dose and organ equivalent dose to human body and protection evaluation.
7.2 Appendix D (normative appendix) gives the conversion coefficient between organ equivalent dose and effective dose per unit free air kerma when monoenergetic photon beam is incident on human body model under various irradiation geometric conditions. Since the value of the radiation weight factor of photon is 1, the organ dose D per unit free air kerma is numerically equal to the organ equivalent dose H per unit free air kerma, so the conversion coefficients in the appendix are expressed in terms of organ dose D per unit free air kerma. Irradiation geometric conditions include anterior-posterior (AP), posterior-anterior (PA) irradiation, left side (LLAT) or right side (RLAT) irradiation, average of left and right side irradiation (LAT), irradiation with 360 degrees rotation (ROT) around the longitudinal axis of the model, and isotropic (ISO) irradiation.
8 Conversion coefficient between practical quantity and protective quantity The ratio between protective quantity and practical quantity depends on the photon energy and the irradiation geometry, and there is no one-to-one correspondence. For a certain photon energy and a certain irradiation geometry, the ratio between protective quantity and practical quantity can be obtained from the data in Appendix B (normative appendix) and Appendix C (normative appendix) and the relevant data in Appendix D (normative appendix). For example, from Table B1 in Appendix B (normative appendix) and Table D1 in Appendix D (normative appendix), the ratio of ambient dose equivalent H* (10) and effective dose E corresponding to different energies and different irradiation geometry conditions can be obtained. 4
Appendix A
(Normative appendix)
Conversion coefficient between monoenergetic photon free air kerma K, photon fluence @ and irradiation quantity X A1 K of monoenergetic photons with energy E,.
The relationship between Φ and X is shown in formula A1-A3.
=160.22.mE
8.76/(1-g)
In formula A1: Ka/Φ is in pGycm2; ur/p is the mass attenuation coefficient of air, in cmg; E is the photon energy, in MeV; In formula A2: KaX is in mGyR: g is the radiation loss of free air kerma, X/Φ is in nRcm; Hen/p is the mass-energy absorption coefficient of air, dimensionless, its value is shown in Table A1: In formula A3: in cmg; E is the photon energy, in MeV. The conversion coefficients between K, @ and X obtained by formula A1-A3 are shown in Table A1. Table A1
Conversion coefficients between monoenergetic photon free air kerma K, photon fluence Φ and exposure dose X Photon energy
Data in this table are quoted from ICRU Report No. 47
1R=2.58×10tc·kg
Because the electron balance in air above 3MeV no longer holds, the exposure dose 1-g is no longer used
Appendix B
(Normative Appendix)
Conversion coefficients of photon free air kerma K, photon fluence @ and exposure dose to ambient dose equivalent H* (10) and directional dose equivalent H(0.07, 0°) B1 The relationship between the ambient dose equivalent H*(10) of photons with energy ranging from 20keV to 10MeV and the free air kerma K can be estimated according to formula (B1).
(ax2 + bx +c)
+d·arctan(gx)
Where: H*(10)/K, the unit is SvGyX=ln(E/E), E is the photon energy (keV): E-9.85keV: a=1.465, b=-4.414, c-4.789, d=0.7006, g-0.6519; the angle unit is radian. The relationship between the photon directional dose equivalent H (0.07, 0°) of B2 energy from 10keV250keV and the free air kerma K can be estimated according to formula (B2).
H(0.07,0)
=a+bx+cxd.exp(gx)
Where: H(0.07.0°)/K is in SvGy; X=ln(E/Eo), E is the photon energy (keV), E-9.85keVa=0.9505, b=0.09432, c=0.2302, d=5.082, g=-0.6997: The angle is in radians. B3 The conversion coefficients from photon fluence @ and free air kerma K to ambient dose equivalent H*(10) and directional dose equivalent H(0.07,0°) are shown in Table B1. B4 The conversion coefficients of free air kerma K and exposure X to ambient dose equivalent F (10) and directional dose equivalent H (0.07.0°) under the filtered X-ray reference radiation conditions specified in GB-12162 are shown in Table B2. The conversion coefficients of free air kerma K to directional dose equivalent H (10.0°) and H (0.07, 0°) and the angle-dependent coefficients are shown in Tables B3 and B4. Table B1 Conversion coefficients of free air kerma K to ambient dose equivalent H* (10) and directional dose equivalent H (0.07.0°) from photon fluence Φ and free air kerma K toConversion coefficients of photon energy to ambient dose equivalent H (0.07.0°)
F(10)/K
Sv Gy!
H(0.07,0°)/K
Sv Gy!
F(10)/@
H*(0. 07, 0°)/@
Photon energy
Continued Table B1 Conversion coefficients of photon fluence Φ and free air kerma K to ambient dose equivalent H (0.07.0°)
H*(10) and directional dose equivalent
H*(10)/K
H(0.07,0°)K
Sv Gy!
Data in this table are quoted from ICRP Publication 74
pGy cm
H*(10)/Φ
pSvcm2
H(0.07,0°)/Φ
Table B2Conversion coefficients of photon free air release K and exposure X to ambient dose H(0.07,0°) under filtered X-ray reference radiation conditions specified in GB12162)
and directional dose equivalent
dose equivalent H*(10)No
Tube voltage
Additional filtering2)
1) The data in this table are quoted from ICRU Report No. 47
H*(10)/Ka
2) In addition to additional filtering, the machine is The inherent filtration of 60keV is 4mmAlConversion coefficients
H*(10)/X
H(0.07.0°)/Ka
H(0.07.00)/X
Table B3 Free air kerma to H(10, H(10.0°)/K.
) conversion coefficients and angle dependence coefficients
Corresponding ratios for different angles αH(10,α)/H(100°)15°
This table data is quoted from ICRP Publication 74
Table B4 Free air kerma to H(0.07, photon energy
H(0. 07, 0°)/ The ratio of "K
0° conversion coefficient and angle dependence coefficient" corresponding to different angles α
The data in this table are quoted from ICRP Publication 74
Appendix C
(Normative Appendix)
The conversion coefficient and angle dependence coefficient of the monoenergetic photon free air kerma K to the personal dose equivalent H (10, 0°) and H (0.07, 0°) of the ICRU flat plate The conversion coefficient and angle dependence coefficient of the free air kerma K to the personal dose equivalent H, (10, 0°) and Hp (0.07, 0°) of the ICRU flat plate are shown in Table C1 and Table C2, the data in the table are quoted from ICRP Publication 74. Table C1
Conversion factors of free air kerma K to ICRU flat plate personal dose equivalent H (10, 0°) and angle dependence
Photon energy
H(10,0°)/K
Photon energy
Ratio of different angles α H(10,
α)/H(10,0°
Conversion factors of free air kerma K to ICRU flat plate personal dose equivalent H and angle dependence
H,(0.07, 0°)/ K.
Ratio of different angles α
α)/H(0.07, 0°)/ K.
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