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Radiation dose exposure during cardiac and peripheral arteries catheterisation
International Journal of Cardiology 113 (2006) 283 – 284 www.elsevier.com/locate/ijcard
Letter to the Editor
Radiation dose exposure during cardiac and peripheral arteries catheterisation D. Kocinaj a, A. Cioppa a, G. Ambrosini a, T. Tesorio a, L. Salemme a, G. Sorropago a, P. Rubino a, E. Picano b,* b
a Casa di Cura Convenzionata ‘‘Montevergine’’, Mercogliano, Italy CNR, Institute of Clinical Physiology, Via Moruzzi, 1, 56124, Pisa, Italy
Received 5 September 2005; accepted 20 September 2005 Available online 2 December 2005
Abstract Background: Ionising radiation carries an oncogenic risk which is linearly related to the dose. An estimation of the effective dose can be obtained from the measurements of the dose – area product (DAP), which is a measure of stochastic risk and a potential quality indicator. Aim: To assess radiation exposure of patients in a large volume cardiac cath-lab. Methods: A retrospective analysis of adult cardiac and peripheral percutaneous procedures (April to December 2004) was carried out to determine the DAP and estimated risk of malignancy. We identified 6 groups: Group 1 (n = 100, coronary angiography and ventriculography); Group 2 (n = 50, carotid stenting); Group 3 (n = 50, aortography + coronary angiography + ventriculography); Group 4 (n = 100, inferior extremities angiography + predilatation and stenting); Group 5 (n = 100, coronary angiography + ventriculography + direct coronary stenting); Group 6 (n = 100, coronary angiography + ventriculography + coronary predilation and stenting). Dose – area product meter attached on the X-ray unit was used for the estimation of the radiation dose received by the patient during the procedures. Results: DAP values (mean T S.D.) ranged from 41 T 30 Gy cm2 in Group 1 (lowest) to 118 T 89 Gy cm2 in Group 6 (highest). Within each group, individual radiation exposure varies substantially: from 11 to 200 Gy cm2 in Group 1, and from 30 to 733 Gy cm2 in Group 6 patients. Average exposure in a Group 6 patient corresponds to a risk of mortality from a malignancy of about 1 in 1000. Conclusion: The radiation dose varies substantially across different types of procedures and up to tenfold within the same procedure. The enhanced knowledge of radiation dose might help the cardiologist to implement radiation sparing procedures eventually minimizing patient and operator radiation hazards in invasive cardiology. D 2005 Elsevier Ireland Ltd. All rights reserved. Keywords: Radiation; Catheterization; Malignancy
In interventional cardiology, radiation dose is best estimated by the Dose Area Product (DAP), which is the absorbed dose to air multiplied by the X-ray beam crosssectional area at the point of measurement and it is expressed in Gycm2 [1]. According to a recent statement of the ACC/AHA, ‘‘the DAP delivered to a patient during a procedure is both a measure of stochastic risk and a potential quality indicator. Physicians should be made aware of the exposures they deliver to their patients and how they
* Corresponding author. Tel.: +39 50 3152400; fax: +39 50 3152374. E-mail address: [email protected] (E. Picano). 0167-5273/$ - see front matter D 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2005.09.035
compare to established norms’’ [1]. Unfortunately, radiological awareness is largely suboptimal in the real world [2,3,4], even among radiologists [5,6]. A retrospective analysis has been performed in order to determine the DAP in different invasive cardiovascular procedures and its estimated risk of malignancy. The data of a total 500 adult patients have been obtained from the electronic data bank of the Hemodynamic Department of the Montevergine Cardiovascular Clinic of Mercogliano. The X-ray equipments used in this study were Philips Integris H5000C Monoplane and Integris Allura Monoplane with the X-ray tube for both Systems: MRC 200 0508 ROT GS 1001. Using the conversion factor derived from the
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D. Kocinaj et al. / International Journal of Cardiology 113 (2006) 283 – 284
Table 1 DAP, effective dose, multiplies of chest X-ray and risk of cancer in our study population N
Group Group Group Group Group Group
1 2 3 4 5 6
100 50 50 100 100 100
DAP [Gycm2]
Equivalent of chest X-rays
Effective dose [mSv]
Fatal cancer risk (%)
Mean T SD
Range
Median
1st quartile
3rd quartile
Mean
Mean
Mean
41 T 30 55 T 31 62 T 40 64 T 51 82 T 49 119 T 89
11 – 200 17 – 156 19 – 233 10 – 311 15 – 361 30 – 733
33 46 51 49 70 99
25 33 40 37 53 72
50 70 70 73 93 133
364 502 547 620 776 1069
7 10 11 12 16 21
0.03 0.04 0.04 0.04 0.06 0.09
Group 1 (coronary angiography and ventriculography); Group 2 (carotid stenting); Group 3 (aortography + coronary angiography + ventriculography); Group 4 (inferior extremities angiography + predilatation and stenting); Group 5 (coronary angiography + ventriculography + direct coronary stenting); Group 6 (coronary angiography + ventriculography + coronary predilation and stenting).
literature, from DAP (automatically provided by the radiological apparatus) the effective dose [7], the radiation dose was expressed in multiples of chest X-rays [8], and the hypothetical risk of fatal cancer were calculated [9]. Six different common procedural groups have been identified in each group, consecutive patients were considered for analysis within the predetermined time frame. Data are reported in Table 1. In the overall population of the patients, there was a significant correlation between DAP and total procedural time (r = .69, p < 0.01). The British National Radiation Protection Board has proposed a reference dose of 36 Gycm2 for a coronary angiogram based on a large UK survey [10]. This compares well with 41.3 Gycm2 that we observed in the coronary angiography and ventriculography Group I. The European DIMOND approach to defining dose reference levels has proposed 75 Gycm2 for coronary angioplasty [11]. Again, this compares well with our reported average value of 119 for Group 6, which includes coronary angiography +ventriculography + coronary predilation + stenting. Our data also confirm that doses vary in a fluoroscopic examination by factors of 10 or more due to variation in dose delivered per minute and number of minutes consumed. To minimize both individual and social risks, the physician – according to recent guidelines – ‘‘must possess the knowledge to recognize patients and circumstances in which the risk of radiationinduced injury is increased’’ [1]. The first step to acquiring this knowledge is to know what your doses are (audit) and the second step is to know what every body else’s doses are (feedback). This is especially important in interventional radiology, which accounts for 2% of all radiological procedures but for 29% of the total effective dose [12]. A greater awareness of the radiological dose and the potential biological damage associated with the dose employed [13] will unavoidably produce greater appropriateness [14].
References [1] Hirshfeld JW, Balter S, Brinker JA, et al. ACCF/AHA/HRS/SCAI Clinical competence statement on physician knowledge to optimize patient safety and image quality in fluoroscopically guided invasive
[2]
[3]
[4] [5]
[6]
[7]
[8]
[9]
[10]
[11] [12] [13]
[14]
cardiovascular Procedures: a report of the American College of Cardiology Foundation/American Heart Association/American College of Physicians Task Force on Clinical Competence and Training. Circulation 2005 (Feb.);111:511 – 32. Finestone A, Schlesinger T, Amir H, Richter E, Milgrom C. Do physicians correctly estimate radiation risks from medical imaging? Arch Environ Health 2003 (Jan.);58:59 – 61. Shiralkar S, Rennie A, Snow M, Galland RB, Lewis MH, GowerThomas K. Doctors’ knowledge of radiation exposure: questionnaire study. BMJ 2003;327:371 – 2. Jacob K, Vivian G, Steel JR. X-ray dose training: are we exposed to enough? Clin Radiol 2004;59:928 – 34. Lee CI, Haims AH, Monico EP, Brink JA, Forman HP. Diagnostic CT scans: assessment of patient, physician, and radiologist awareness of radiation dose and possible risks. Radiology 2004;231:393 – 8. Correia MJ, Hellies A, Andreassi MG, Ghelarducci B, Picano E. Lack of radiological awareness in a tertiary care cardiological centre. Int J Cardiol 2005;103:307 – 11. Betsou S, Efstathopoulos EP, Katritsis D, Faulkner K, Panayiotakis G. Patient radiation doses during cardiac catheterisation procedures. Br J Radiol 1998;71:634 – 9. European Commission. Radiation protection 118: referral guidelines for imaging. Luxemburg: Office for Official Publications of the European Communities, 2001. http://europa.eu.int/comm/environment/ radprot/118/rp-118-en.pdf (accessed 27 Jul 2005). International Commission on Radiological Protection. Radiation and your patient: a guide for medical practitioners. 2001. www.icrp.org/ docs/Rad_for_GP_for_web.pdf (accessed 27 Jul 2005). Hart, D., Hiller, M.C., Wall, B.F., Doses to patients from medical Xray examinations in the UK-2000 review. NRPB-W14 Chilton, NRPB (2000). Neofistou V, Vano E, Padovani R, et al. Preliminary reference levels in interventional cardiology. Eur Radiol 2003;13:2259 – 63. Regulla DF, Eder H. Patient exposure in medical X-ray imaging in Europe. Radiat Prot Dosimetry 2005;114:11 – 25. Andreassi MG. The biological effects of diagnostic cardiac imaging on professionally exposed physicians: the importance of being nonionizing. Cardiovasc Ultrasound 2004 (Nov. 22);2(1):25. Picano E. Sustainability of medical imaging. Education and debate. BMJ 2004;328:842 – 6.
Letter to the Editor
Radiation dose exposure during cardiac and peripheral arteries catheterisation D. Kocinaj a, A. Cioppa a, G. Ambrosini a, T. Tesorio a, L. Salemme a, G. Sorropago a, P. Rubino a, E. Picano b,* b
a Casa di Cura Convenzionata ‘‘Montevergine’’, Mercogliano, Italy CNR, Institute of Clinical Physiology, Via Moruzzi, 1, 56124, Pisa, Italy
Received 5 September 2005; accepted 20 September 2005 Available online 2 December 2005
Abstract Background: Ionising radiation carries an oncogenic risk which is linearly related to the dose. An estimation of the effective dose can be obtained from the measurements of the dose – area product (DAP), which is a measure of stochastic risk and a potential quality indicator. Aim: To assess radiation exposure of patients in a large volume cardiac cath-lab. Methods: A retrospective analysis of adult cardiac and peripheral percutaneous procedures (April to December 2004) was carried out to determine the DAP and estimated risk of malignancy. We identified 6 groups: Group 1 (n = 100, coronary angiography and ventriculography); Group 2 (n = 50, carotid stenting); Group 3 (n = 50, aortography + coronary angiography + ventriculography); Group 4 (n = 100, inferior extremities angiography + predilatation and stenting); Group 5 (n = 100, coronary angiography + ventriculography + direct coronary stenting); Group 6 (n = 100, coronary angiography + ventriculography + coronary predilation and stenting). Dose – area product meter attached on the X-ray unit was used for the estimation of the radiation dose received by the patient during the procedures. Results: DAP values (mean T S.D.) ranged from 41 T 30 Gy cm2 in Group 1 (lowest) to 118 T 89 Gy cm2 in Group 6 (highest). Within each group, individual radiation exposure varies substantially: from 11 to 200 Gy cm2 in Group 1, and from 30 to 733 Gy cm2 in Group 6 patients. Average exposure in a Group 6 patient corresponds to a risk of mortality from a malignancy of about 1 in 1000. Conclusion: The radiation dose varies substantially across different types of procedures and up to tenfold within the same procedure. The enhanced knowledge of radiation dose might help the cardiologist to implement radiation sparing procedures eventually minimizing patient and operator radiation hazards in invasive cardiology. D 2005 Elsevier Ireland Ltd. All rights reserved. Keywords: Radiation; Catheterization; Malignancy
In interventional cardiology, radiation dose is best estimated by the Dose Area Product (DAP), which is the absorbed dose to air multiplied by the X-ray beam crosssectional area at the point of measurement and it is expressed in Gycm2 [1]. According to a recent statement of the ACC/AHA, ‘‘the DAP delivered to a patient during a procedure is both a measure of stochastic risk and a potential quality indicator. Physicians should be made aware of the exposures they deliver to their patients and how they
* Corresponding author. Tel.: +39 50 3152400; fax: +39 50 3152374. E-mail address: [email protected] (E. Picano). 0167-5273/$ - see front matter D 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2005.09.035
compare to established norms’’ [1]. Unfortunately, radiological awareness is largely suboptimal in the real world [2,3,4], even among radiologists [5,6]. A retrospective analysis has been performed in order to determine the DAP in different invasive cardiovascular procedures and its estimated risk of malignancy. The data of a total 500 adult patients have been obtained from the electronic data bank of the Hemodynamic Department of the Montevergine Cardiovascular Clinic of Mercogliano. The X-ray equipments used in this study were Philips Integris H5000C Monoplane and Integris Allura Monoplane with the X-ray tube for both Systems: MRC 200 0508 ROT GS 1001. Using the conversion factor derived from the
284
D. Kocinaj et al. / International Journal of Cardiology 113 (2006) 283 – 284
Table 1 DAP, effective dose, multiplies of chest X-ray and risk of cancer in our study population N
Group Group Group Group Group Group
1 2 3 4 5 6
100 50 50 100 100 100
DAP [Gycm2]
Equivalent of chest X-rays
Effective dose [mSv]
Fatal cancer risk (%)
Mean T SD
Range
Median
1st quartile
3rd quartile
Mean
Mean
Mean
41 T 30 55 T 31 62 T 40 64 T 51 82 T 49 119 T 89
11 – 200 17 – 156 19 – 233 10 – 311 15 – 361 30 – 733
33 46 51 49 70 99
25 33 40 37 53 72
50 70 70 73 93 133
364 502 547 620 776 1069
7 10 11 12 16 21
0.03 0.04 0.04 0.04 0.06 0.09
Group 1 (coronary angiography and ventriculography); Group 2 (carotid stenting); Group 3 (aortography + coronary angiography + ventriculography); Group 4 (inferior extremities angiography + predilatation and stenting); Group 5 (coronary angiography + ventriculography + direct coronary stenting); Group 6 (coronary angiography + ventriculography + coronary predilation and stenting).
literature, from DAP (automatically provided by the radiological apparatus) the effective dose [7], the radiation dose was expressed in multiples of chest X-rays [8], and the hypothetical risk of fatal cancer were calculated [9]. Six different common procedural groups have been identified in each group, consecutive patients were considered for analysis within the predetermined time frame. Data are reported in Table 1. In the overall population of the patients, there was a significant correlation between DAP and total procedural time (r = .69, p < 0.01). The British National Radiation Protection Board has proposed a reference dose of 36 Gycm2 for a coronary angiogram based on a large UK survey [10]. This compares well with 41.3 Gycm2 that we observed in the coronary angiography and ventriculography Group I. The European DIMOND approach to defining dose reference levels has proposed 75 Gycm2 for coronary angioplasty [11]. Again, this compares well with our reported average value of 119 for Group 6, which includes coronary angiography +ventriculography + coronary predilation + stenting. Our data also confirm that doses vary in a fluoroscopic examination by factors of 10 or more due to variation in dose delivered per minute and number of minutes consumed. To minimize both individual and social risks, the physician – according to recent guidelines – ‘‘must possess the knowledge to recognize patients and circumstances in which the risk of radiationinduced injury is increased’’ [1]. The first step to acquiring this knowledge is to know what your doses are (audit) and the second step is to know what every body else’s doses are (feedback). This is especially important in interventional radiology, which accounts for 2% of all radiological procedures but for 29% of the total effective dose [12]. A greater awareness of the radiological dose and the potential biological damage associated with the dose employed [13] will unavoidably produce greater appropriateness [14].
References [1] Hirshfeld JW, Balter S, Brinker JA, et al. ACCF/AHA/HRS/SCAI Clinical competence statement on physician knowledge to optimize patient safety and image quality in fluoroscopically guided invasive
[2]
[3]
[4] [5]
[6]
[7]
[8]
[9]
[10]
[11] [12] [13]
[14]
cardiovascular Procedures: a report of the American College of Cardiology Foundation/American Heart Association/American College of Physicians Task Force on Clinical Competence and Training. Circulation 2005 (Feb.);111:511 – 32. Finestone A, Schlesinger T, Amir H, Richter E, Milgrom C. Do physicians correctly estimate radiation risks from medical imaging? Arch Environ Health 2003 (Jan.);58:59 – 61. Shiralkar S, Rennie A, Snow M, Galland RB, Lewis MH, GowerThomas K. Doctors’ knowledge of radiation exposure: questionnaire study. BMJ 2003;327:371 – 2. Jacob K, Vivian G, Steel JR. X-ray dose training: are we exposed to enough? Clin Radiol 2004;59:928 – 34. Lee CI, Haims AH, Monico EP, Brink JA, Forman HP. Diagnostic CT scans: assessment of patient, physician, and radiologist awareness of radiation dose and possible risks. Radiology 2004;231:393 – 8. Correia MJ, Hellies A, Andreassi MG, Ghelarducci B, Picano E. Lack of radiological awareness in a tertiary care cardiological centre. Int J Cardiol 2005;103:307 – 11. Betsou S, Efstathopoulos EP, Katritsis D, Faulkner K, Panayiotakis G. Patient radiation doses during cardiac catheterisation procedures. Br J Radiol 1998;71:634 – 9. European Commission. Radiation protection 118: referral guidelines for imaging. Luxemburg: Office for Official Publications of the European Communities, 2001. http://europa.eu.int/comm/environment/ radprot/118/rp-118-en.pdf (accessed 27 Jul 2005). International Commission on Radiological Protection. Radiation and your patient: a guide for medical practitioners. 2001. www.icrp.org/ docs/Rad_for_GP_for_web.pdf (accessed 27 Jul 2005). Hart, D., Hiller, M.C., Wall, B.F., Doses to patients from medical Xray examinations in the UK-2000 review. NRPB-W14 Chilton, NRPB (2000). Neofistou V, Vano E, Padovani R, et al. Preliminary reference levels in interventional cardiology. Eur Radiol 2003;13:2259 – 63. Regulla DF, Eder H. Patient exposure in medical X-ray imaging in Europe. Radiat Prot Dosimetry 2005;114:11 – 25. Andreassi MG. The biological effects of diagnostic cardiac imaging on professionally exposed physicians: the importance of being nonionizing. Cardiovasc Ultrasound 2004 (Nov. 22);2(1):25. Picano E. Sustainability of medical imaging. Education and debate. BMJ 2004;328:842 – 6.