Correspondence Conversion coefficients from fluence and air kerma to dose equivalent quantities THE EDITOR—SIR,
Following the publication of the International Commission on Radiation Units and Measurements Report 39 (ICRU, 1985), the British Committee on Radiation Units and Measurements issued a memorandum (BCRU, 1986) recommending the adoption of the quantities ambient dose equivalent H*(d) and directional dose equivalent H'(d) for area monitoring in the UK, and conversion coefficients and conversion relationships fromfluenceand air kerma to these quantities were given in an appendix. The promulgation of these conversion coefficients was in advance of any specific recommendation on conversion coefficients by the ICRU. The BCRU undertook to review the situation following any subsequent recommendations by the ICRU. The ICRU Report 43 (ICRU, 1988) is now available and contains data on the same conversion coefficients, mainly in graphical form. The data for photons and neutrons is identical to that already recommended (BCRU, 1986). In the case of electrons, however, the BCRU memorandum gave a single mean value for the conversion coefficient for electronfluenceto ambient dose equivalent H*(10) in the energy range 5 MeV to 50MeV, whereas ICRU Report 43 contains more detail, tabulating conversion coefficients to both ambient and directional dose equivalent in the energy range 4 MeV to 21.4 MeV. Since the publication of the BCRU 1986 memorandum, Publication 51 of the International Commission on Radiological Protection (ICRP, 1987) has also provided similar conversion coefficients. In the case of photons there is some divergence between the ICRU and the ICRP data, particularly at energies near 15 keV. However it has been shown (Bohm and Grosswendt, 1989) that for a range of X-ray spectra, weighted conversion coefficients from air kerma to H'(10) or H*(10) are significantly different only for spectra with maximum photon energies of 20 keV and below when either the ICRU or ICRP data are used. For neutrons at energies where the ICRU and ICRP data may be compared, divergencies in the coefficients of H*(lO)/0 of up to 9% are apparent. The data for electrons in ICRP Publication 51 refers to a 30 cm thick semi-infinite slab phantom rather than to the ICRU sphere. On the basis of a recent review of the ICRU and ICRP publications, the BCRU now recommends that in the United Kingdom, for the conversion from fluence and air kerma to dose equivalent quantities, (l)for photons and neutrons, the conversion coefficients and conversion relationships contained in the BCRU 1986 memorandum should continue to be used; these conversion coefficients are identical to those presented in ICRU 43 and (2) for electrons, the conversion coefficients contained in ICRU 43 should be used and not the single mean value previously recommended (BCRU, 1986). Yours etc.,
BOHM, J. & GROSSWENDT, B., 1989. 10 years of intercomparison
measurements of dosemeter systems for the individual monitoring of photon and beta radiation. PTB Mitteilungen, 99, 107-118. ICRP, 1987. Data for use in Protection Against External Radiation, ICRP Publication 51 (Pergamon Press, Oxford). ICRU, 1985. Determination of Dose Equivalents Resulting from External Radiation Sources, ICRU Report 39 (International Commission on Radiation Units and Measurements, Bethesda, MD). ICRU, 1988. Determination of Dose Equivalents from External Radiation Sources—Part 2, ICRU Report 43 (International Commission on Radiation Units and Measurements, Bethesda, MD).
Reactions to intravenous contrast media THE EDITOR—SIR,
Idiosyncratic reactions are a recognized and documented complication of intravenous contrast media. Angioneurotic oedema is a relatively common feature of both intermediate (9%) and severe (16%) contrast media reactions. (Ansell, 1987). Typically, it involves the eyelids, lips, tongue and, in
M . J. ROSSITER
Secretary BCRU National Physical Laboratory, Teddington, Middlesex TW11 OLW {Received October 1989) References BCRU, 1986. New quantities in radiation protection and conversion coefficients. British Journal of Radiology, 59, Figure 1. Open mouth view demonstrating the oedematous buccal mucosa. 946-950. 230
The British Journal of Radiology, March 1990
Correspondence more severe cases, the larynx. We recently encountered a case of angioneurotic oedema following intravenous contrast medium resulting in an unusual distribution of swelling. A 52-year-old woman with known renal calculi was admitted with a history of left ureteric colic. Contrast medium (presumed to be high osmolar ionic) had been administered previously for intravenous urography without any adverse reaction. There was no history of allergy, asthma, eczema, diabetes, renal failure or cardiac disease. Biochemical renal function was normal. An intravenous urogram was performed using a bolus of 100 ml of sodium meglumine diatrizoate (Urografin 370, Schering), equivalent to 0.4 g iodine/kg. Within a few minutes the patient complained of facial discomfort and was noted to have facial flushing and significant swelling of her cheeks. Inspection of the inside of the mouth revealed that there was also marked bilateral oedema of the buccal mucosa (Fig. 1). The parotid glands were neither swollen nor tender. She also developed a solitary urticarial lesion on the anterior chest wall but no bronchospasm, laryngeal, periorbital or lingual oedema and no cardiovascular disturbance. Treatment with intravenous chlorpheniramine 10 mg was given immediately, but neither adrenaline nor steroids were necessary. After 20 min the discomfort and the intense swelling reduced and gradually subsided over a period of several hours. By 24 h, the patient's facial appearance had largely returned to normal, but it was 2 weeks before she considered that the swelling had totally resolved. The range of reactions to intravenous contrast media and their postulated mechanisms are well described by Ansell (1987). Angioneurotic oedema from various causes is reported to involve the eyelids in 69%, the lips in 65%, the tongue in 21% and other areas in 15% (Champion et al, 1969), Oedema confined to the cheeks and buccal mucosa is an unusual phenomenon, which does not appear to have been reported following use of intravenous contrast media. Ansell (1987) states that the main value of HI antihistamines is in the treatment of urticarial reactions of angioneurotic
Vol. 63, No. 747
oedema, and in this case they proved satisfactory, without needing adrenaline or steroids. The main differential diagnosis of this reaction is bilateral parotid gland swelling which is a well recognized, immediate, though transient reaction following use of contrast media which may last several hours (Navani et al, 1972; St Amour et al, 1986). Angioneurotic oedema can present in a variety of ways and it is important that radiologists are aware of and can recognize the early signs of its development at unusual sites, so that prompt treatment may prevent more serious sequelae. Yours, etc., J. S. TUCK D. F. MARTIN
Department of Diagnostic Radiology, University Hospital of South Manchester, Nell Lane, Manchester M20 8LR {Received November 1989) References ANSELL, G. (Ed.), 1987. Contrast Media and Urography. In Complications in Diagnostic Imaging (2nd edn). Ed. by G. Ansell and R. A. Wilkins. (Blackwell Scientific Publications, Oxford), pp. 1-36. CHAMPION, R. H.,
ROBERTS, S. O. B., CARPENTER, R. G.
&
ROGER, J. H., 1969. Urticaria and angio-oedema. A review of 554 patients. British Journal of Dermatology, 81, 588-597. NAVANI, S., TAYLOR, C. E., KAUFMAN, S. A. & PARLE, R.
H.,
1972. Evanescent enlargement of salivary glands following tri-iodinated contrast media. British Journal of Radiology, 45, 19-20. ST AMOUR, T. E., MCLENNAN, B. L. & GLAZER, H. S.,
1986.
Pancreatic mumps: a transient reaction to I.V. contrast media (Case report). American Journal of Roentgenology, 147, 188-189.
231
Following the publication of the International Commission on Radiation Units and Measurements Report 39 (ICRU, 1985), the British Committee on Radiation Units and Measurements issued a memorandum (BCRU, 1986) recommending the adoption of the quantities ambient dose equivalent H*(d) and directional dose equivalent H'(d) for area monitoring in the UK, and conversion coefficients and conversion relationships fromfluenceand air kerma to these quantities were given in an appendix. The promulgation of these conversion coefficients was in advance of any specific recommendation on conversion coefficients by the ICRU. The BCRU undertook to review the situation following any subsequent recommendations by the ICRU. The ICRU Report 43 (ICRU, 1988) is now available and contains data on the same conversion coefficients, mainly in graphical form. The data for photons and neutrons is identical to that already recommended (BCRU, 1986). In the case of electrons, however, the BCRU memorandum gave a single mean value for the conversion coefficient for electronfluenceto ambient dose equivalent H*(10) in the energy range 5 MeV to 50MeV, whereas ICRU Report 43 contains more detail, tabulating conversion coefficients to both ambient and directional dose equivalent in the energy range 4 MeV to 21.4 MeV. Since the publication of the BCRU 1986 memorandum, Publication 51 of the International Commission on Radiological Protection (ICRP, 1987) has also provided similar conversion coefficients. In the case of photons there is some divergence between the ICRU and the ICRP data, particularly at energies near 15 keV. However it has been shown (Bohm and Grosswendt, 1989) that for a range of X-ray spectra, weighted conversion coefficients from air kerma to H'(10) or H*(10) are significantly different only for spectra with maximum photon energies of 20 keV and below when either the ICRU or ICRP data are used. For neutrons at energies where the ICRU and ICRP data may be compared, divergencies in the coefficients of H*(lO)/0 of up to 9% are apparent. The data for electrons in ICRP Publication 51 refers to a 30 cm thick semi-infinite slab phantom rather than to the ICRU sphere. On the basis of a recent review of the ICRU and ICRP publications, the BCRU now recommends that in the United Kingdom, for the conversion from fluence and air kerma to dose equivalent quantities, (l)for photons and neutrons, the conversion coefficients and conversion relationships contained in the BCRU 1986 memorandum should continue to be used; these conversion coefficients are identical to those presented in ICRU 43 and (2) for electrons, the conversion coefficients contained in ICRU 43 should be used and not the single mean value previously recommended (BCRU, 1986). Yours etc.,
BOHM, J. & GROSSWENDT, B., 1989. 10 years of intercomparison
measurements of dosemeter systems for the individual monitoring of photon and beta radiation. PTB Mitteilungen, 99, 107-118. ICRP, 1987. Data for use in Protection Against External Radiation, ICRP Publication 51 (Pergamon Press, Oxford). ICRU, 1985. Determination of Dose Equivalents Resulting from External Radiation Sources, ICRU Report 39 (International Commission on Radiation Units and Measurements, Bethesda, MD). ICRU, 1988. Determination of Dose Equivalents from External Radiation Sources—Part 2, ICRU Report 43 (International Commission on Radiation Units and Measurements, Bethesda, MD).
Reactions to intravenous contrast media THE EDITOR—SIR,
Idiosyncratic reactions are a recognized and documented complication of intravenous contrast media. Angioneurotic oedema is a relatively common feature of both intermediate (9%) and severe (16%) contrast media reactions. (Ansell, 1987). Typically, it involves the eyelids, lips, tongue and, in
M . J. ROSSITER
Secretary BCRU National Physical Laboratory, Teddington, Middlesex TW11 OLW {Received October 1989) References BCRU, 1986. New quantities in radiation protection and conversion coefficients. British Journal of Radiology, 59, Figure 1. Open mouth view demonstrating the oedematous buccal mucosa. 946-950. 230
The British Journal of Radiology, March 1990
Correspondence more severe cases, the larynx. We recently encountered a case of angioneurotic oedema following intravenous contrast medium resulting in an unusual distribution of swelling. A 52-year-old woman with known renal calculi was admitted with a history of left ureteric colic. Contrast medium (presumed to be high osmolar ionic) had been administered previously for intravenous urography without any adverse reaction. There was no history of allergy, asthma, eczema, diabetes, renal failure or cardiac disease. Biochemical renal function was normal. An intravenous urogram was performed using a bolus of 100 ml of sodium meglumine diatrizoate (Urografin 370, Schering), equivalent to 0.4 g iodine/kg. Within a few minutes the patient complained of facial discomfort and was noted to have facial flushing and significant swelling of her cheeks. Inspection of the inside of the mouth revealed that there was also marked bilateral oedema of the buccal mucosa (Fig. 1). The parotid glands were neither swollen nor tender. She also developed a solitary urticarial lesion on the anterior chest wall but no bronchospasm, laryngeal, periorbital or lingual oedema and no cardiovascular disturbance. Treatment with intravenous chlorpheniramine 10 mg was given immediately, but neither adrenaline nor steroids were necessary. After 20 min the discomfort and the intense swelling reduced and gradually subsided over a period of several hours. By 24 h, the patient's facial appearance had largely returned to normal, but it was 2 weeks before she considered that the swelling had totally resolved. The range of reactions to intravenous contrast media and their postulated mechanisms are well described by Ansell (1987). Angioneurotic oedema from various causes is reported to involve the eyelids in 69%, the lips in 65%, the tongue in 21% and other areas in 15% (Champion et al, 1969), Oedema confined to the cheeks and buccal mucosa is an unusual phenomenon, which does not appear to have been reported following use of intravenous contrast media. Ansell (1987) states that the main value of HI antihistamines is in the treatment of urticarial reactions of angioneurotic
Vol. 63, No. 747
oedema, and in this case they proved satisfactory, without needing adrenaline or steroids. The main differential diagnosis of this reaction is bilateral parotid gland swelling which is a well recognized, immediate, though transient reaction following use of contrast media which may last several hours (Navani et al, 1972; St Amour et al, 1986). Angioneurotic oedema can present in a variety of ways and it is important that radiologists are aware of and can recognize the early signs of its development at unusual sites, so that prompt treatment may prevent more serious sequelae. Yours, etc., J. S. TUCK D. F. MARTIN
Department of Diagnostic Radiology, University Hospital of South Manchester, Nell Lane, Manchester M20 8LR {Received November 1989) References ANSELL, G. (Ed.), 1987. Contrast Media and Urography. In Complications in Diagnostic Imaging (2nd edn). Ed. by G. Ansell and R. A. Wilkins. (Blackwell Scientific Publications, Oxford), pp. 1-36. CHAMPION, R. H.,
ROBERTS, S. O. B., CARPENTER, R. G.
&
ROGER, J. H., 1969. Urticaria and angio-oedema. A review of 554 patients. British Journal of Dermatology, 81, 588-597. NAVANI, S., TAYLOR, C. E., KAUFMAN, S. A. & PARLE, R.
H.,
1972. Evanescent enlargement of salivary glands following tri-iodinated contrast media. British Journal of Radiology, 45, 19-20. ST AMOUR, T. E., MCLENNAN, B. L. & GLAZER, H. S.,
1986.
Pancreatic mumps: a transient reaction to I.V. contrast media (Case report). American Journal of Roentgenology, 147, 188-189.
231
