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Effective techniques for reduction of radiation dosage to patients undergoing invasive cardiac procedures

¹ Department of Cardiology, Klinik Fraenkische Schweiz, Feuersteinstr. 2, D-91320 Ebermannstadt and ² Department of Cardiology, Ernst Moritz Arndt University, Friedrich-Loeffler Str. 23, D-17487 Greifswald, Germany

Correspondence: Dr Eberhard Kuon

	Abstract

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The goal of this study was to improve radiation dose reduction techniques in invasive cardiology and after patients' radiation data had approached minimal levels, to evaluate predictors of their radiation exposure resulting from invasive cardiac procedures. Over the course of 1 year (and 1996 procedures) we minimized cinegraphic frames and runs, as well as fluoroscopy time, and trained ourselves to achieve effective fluoroscopy-saving positioning of blinds and filters toward the regions of interest. We were consequently able to reduce the mean dose–area products (DAP) for coronary angiography and angioplasty, combined interventions, high-frequency rotational atherectomy, and excimer laser angioplasty: from levels of 53.9 Gy cm², 79.6 Gy cm², 112.3 Gy cm², 119.4 Gy cm², and 168.0 Gy cm² as currently reported in the literature, to 12.9 Gy cm², 13.3 Gy cm², 25.9 Gy cm², 33.0 Gy cm², and 27.1 Gy cm², respectively. The mean DAP due to interventions in acute myocardial infarction was 38.3 Gy cm². DAP was influenced by body mass index, complexity of coronary artery disease, tube angulation, documented structure, coronary recanalization, emergency circumstances, and the percutaneous transluminal coronary angioplasty (PTCA) target vessel involved, but not by stent implantation. By favouring radiation-reducing cranial posteroanterior views over standard left anterior oblique views for visualization of the left anterior descending and the diagonal artery, we consequently achieved mean PTCA-DAPs of 10.4 Gy cm² and 8.6 Gy cm², respectively: levels significantly lower than those for PTCA of the right coronary artery (13.3 Gy cm²), left circumflex artery (13.7 Gy cm²), and obtuse marginal branch (16.9 Gy cm²). In conclusion, enhanced knowledge of radiation dose-reduction techniques significantly reduces patient radiation hazards in invasive cardiology.

	Introduction

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Radiation exposure to patients from invasive cardiac procedures is high. Currently reported and calculated mean dose–area products (DAPs) range from 20.3 Gy cm² to 174.0 Gy cm² (Figure 1) [1–10]. Skin erythema or even ulceration due to radiation exposure during complex intervention may result [11–13]. Accordingly, the new Euratom Council Directive stipulates that "All medical exposure for radiodiagnostic purposes ... shall be kept as low as reasonably achievable (ALARA)" [14]. Toward significantly lessening radiation exposure for patients and staff, we have developed dose-reduction techniques and have subsequently analyzed the various factors influencing radiation-exposure during coronary intervention.

View larger version (19K): [in this window] [in a new window]   Figure 1. Current published reports (references [1–10] black bars) and the authors' own results (white bars) on patient radiation exposure from coronary angiography (CA) and angioplasty (PTCA), percutaneous combined interventions (PCI), high-frequency rotational atherectomy (HFRA) and excimer-laser angioplasty (ELCA).

	Materials and methods

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1. Restriction to essential cinegraphic runs and frames.
   
2. With the exception of bypass grafts, collateral pathways, and slow-flow phenomena, limitation of cinegraphic coronary runs whenever possible to one heart cycle length.
   
3. Consistent systematic use of the low-level fluoroscopy mode.
   
4. Training of fluoroscopy-saving blind positioning to the region of interest, as far as possible, by short taps on the foot switch, with advantage taken of the "Last image hold" function.
   
5. Restriction to the ostial region of interest during intubation of coronary arteries in the largest justifiable image-intensifier field.
   
6. Preference for projections that rotate out the spine: i.e. cranial posteroanterior views, instead of cranial left anterior oblique, to visualize left anterior arteries, and caudal posteroanterior angulations instead of the left anterior oblique spider view for the left coronary main stem bifurcation.
   
7. Application of the ALARA principle in emergency cases, after gaining sufficient reperfusion.
   

Over the course of 1 year one cardiologist performed 982 diagnostic coronary angiographies (CA) and 502 percutaneous transluminal coronary angioplasties (PTCA) selectively with femoral access: radiation exposure data were analyzed over the course of 1 year (Tables 1 and 2). In the first 6 months (period I) the patients' radiation data evidently asymptotically approached minimal levels. Over the following 6 months (period II) we analyzed various influencing factors on the patients' radiation exposure: body mass index, severity of coronary artery disease, partial contributions of left ventriculography, left and right CA, tube angulation, PTCA target vessel, coronary recanalization versus angioplasty, and stent implantation. Furthermore, the same operator analyzed a total of 225 combined percutaneous interventions – CA followed by ad hoc PTCA (PCI) – in acute myocardial infarction as well as for elective conditions and over the course of 1 year, compared radiation data before and after realisation of radiation-reduction techniques, respectively. In addition we investigated 36 excimer-laser coronary angioplasties (ELCA) and 26 high-frequency rotablation atherectomies (HFRA) performed by two cardiologists. We therefore analysed radiation exposure data from 1996 consecutively performed coronary interventions carried out on 1771 patients. Patient data: mean age 61.2±9.4 years; male 66.3%; body mass index=28.3±4.4 kg m^-2.

With account taken of stochastic risk, it is legitimate to add all partial DAP values relative to different sequences, in order to arrive at a DAP per procedure, since all contributions of these values to the effective dose will be comparable. Comparison of publications on radiation exposure to patients, with their various radiation units (Figure 1), requires standardization to the DAP unit Gy cm² [1, 4]. DAP (Gy cm²)0.00876 x DAP (R cm²)ED (mSv)/0.20ESAK (Gy) x (D/2)²/(1.9)². DAP may be estimated from ESAK by calculation of the irradiated patient surface area from published intensifier field-size data (diameter [D]=23, 17, and 13 cm), and on the basis of a focus-image intensifier/focus-skin magnification ratio of approximately 1.9. Reported mean entrance beam-size calculations at the patient's skin of 49.2 cm² for CAs and interventions correlate with our calculations of 62.8 cm² for an intensifier diameter of 17 cm, typical for coronary angiography, and of 36.8 cm² for an intensifier diameter of 13 cm, predominantly used during coronary angioplasty [5]. Conversely, when the totality or an appreciable share of the DAP has been delivered through a single location of the skin, it is legitimate to deduce ESAK by division of DAP by the area of the beam in the plane of the skin.

Equipment, acquisition system, data collection and statistical analysis
We employed a single-arm undercouch tube Integris H3000 intensifier system (Philips Medical Systems, the Netherlands). Throughout all interventions and angulations, we selected the lowest of three grid-controlled fluoroscopy techniques, with a 0.4 mm copper filter and a 1.5 mm aluminium filter installed in the X-ray beam. Under conditions of a focus-image intensifier distance of 1 m, for a metal absorber of 1.5 mm copper plus 25 mm aluminium, and at a range of 70–90 kV, the entrance dose rates during fluoroscopy and cine acquisition (12.5 frames s^-1) were 40 µR s^-1, 56 µR s^-1, and 72 µR s^-1 and 8 µR frame^-1, 16 µR frame^-1, and 23 µR frame^-1 for the 23 cm, 17 cm, and 13 cm image intensifier fields, respectively. DAP was measured by an ionization Diamentor (M2, PTW, Freiburg, Germany), calibrated in situ on the X-ray tube (reliability for repetition <3%; total uncertainty for linearity [60–150 kV] <5%). Table attenuation was equivalent to 0.6 mm aluminium. Calibration factors at 70 kV–90 kV were 1.10 for direct lateral exposures and 0.97 for undercouch exposure perpendicular to the couch. The electrical charge generated is directly proportional to the collimated radiation beam passing the cross-sectional chamber area and the patient's body-surface area.

We measured total DAP as well as DAP due to cinematography (DAP^C) and to fluoroscopy (DAP^F) under conditions of left anterior oblique, right anterior oblique, and posteroanterior angulations. In addition, we documented the number of cinegraphic runs and frames, fluoroscopy and interventional times. DAP^C frame^-1 and DAP^F s^-1 were calculated to demonstrate the efficacy of focusing to the region of interest by use of the collimator. Student's t-tests verified differences in continuous variables. Significance was determined at a 0.05 probability level (p). For table clarity, p-levels <0.000001 were marked by 0.

	Results

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Benefits of optimized dose-reduction techniques
Over the course of 1 year, we modified catheterization techniques and successively reduced the mean overall DAP for diagnostic cardiac catheterization and for PTCA to 12.9 Gy cm² and 13.3 Gy cm², the DAP^C to 8.6 Gy cm² and 4.1 Gy cm², and the DAP^F to 4.3 Gy cm² and 9.2 Gy cm², respectively (Tables 1 and 2). We achieved this reduction primarily over the first 6 months (period I). Predictors influencing radiation exposure were analyzed over the final 6 months (period II) under comparable, optimized procedural conditions. An additional cardiologist reviewed all documentation. Diagnostic disagreement in elective CA was independent of optimized interventional technique (periods I vs. II: 1.0 and 1.1 %, respectively). Fluoroscopic (DAP^F s^-1) and cinegraphic (DAP^C frame^-1) regions of interest during PTCA were smaller than during CA.

Overweight
Unlike the phenomenon of increasing dose parameters observed among overweight patients, their procedural parameters for invasive cardiac catheterization, i.e. cinegraphic runs and frames, fluoroscopic time, and interventional time, remained constant (Table 3). Regression coefficients of DAP to body mass index and body surface area provide a slightly better prediction of overall radiation exposure by body surface area (Figure 2).

View larger version (24K): [in this window] [in a new window]   Figure 2. Straight-line regression of overall dose–area product (DAP) to (a) body mass index (BMI) and (b) body surface area (BSA).

Partial DAP contributions by cardiac catheterization
The partial DAP contributions of left ventriculography and left and right CA were 17%, 52%, and 31%, respectively (n=369). Despite the largest image size, the cinegraphic left ventricular mode ensures significantly lower time-adjusted radiation exposures than do both left and right coronary modes (DAP^C frame^-1: 26.3 mGy cm² versus 48.5 mGy cm² and 53.1 mGy cm², respectively; p=0). Documentation of the left coronary artery with its complex branching required the most cine runs (5.9; p<0.00005), and accordingly amounted to 57% of the cinegraphic DAP^C.

Tube angulation
Tube angulation influences cinegraphic intensity (DAP^C frame^-1) to a large extent (n=33; Figure 3). Left ventriculography involves higher radiation exposure in left anterior oblique (60/0°) than in right anterior oblique (30/0°) projection (p<0.0002). Radiation intensity during left CA evidently increases in left anterior oblique (60°) and caudal (-) angulations, and decreases in left lateral (90/0°) and right anterior oblique angulations. In documentation of bifurcation in the left anterior descending and diagonal artery, the cranial posteroanterior view results in less radiation intensity than does the cranial left anterior oblique (60/20°+) view. The same applies to the caudal posteroanterior view, when applied instead of caudal left anterior oblique (60/20°-) spider view, for recording the left coronary main stem (Figure 4). Cranial views for exact documentation of the right coronary bifurcation at the crux give rise to high radiation intensity.

View larger version (41K): [in this window] [in a new window]   Figure 3. Graph demonstrating the influence of angulation on cinegraphic radiation intensity during left ventriculography (LV) and angiography for left (LCA) and right (RCA) coronary artery. DAP, dose–area product; PA, posteroanterior view; LAO, left anterior oblique view; RAO, right anterior oblique view.

View larger version (66K): [in this window] [in a new window]   Figure 4. Left main stem bifurcation in (a) caudal posteroanterior (PA 0°/30°-) and (b) caudal left anterior oblique spider view (LAO 60°/20°-).

Stent implantation
Stenting during PTCA (n=80 versus 148) resulted in significantly more cinegraphic runs (10.0 versus 7.7; p0.000003) and longer fluoroscopic time (9.6 versus 7.7 min.; p<0.005), but the difference in overall DAP (15.9 versus 14.1 Gy cm²) did not reach the significance level.

Emergency interventions
Shortening cinegraphic runs, cutting fluoroscopy time, and consistent restriction to the coronary region of interest by use of the collimator after initial reperfusion reduced the emergency-induced DAP surplus of combined interventions, i.e. CA including ad hoc PTCA, from 100% to 47% (n=225, Table 5). In the course of 1 year, the mean total DAP for emergency and elective combined interventions decreased by 46% and 27%, respectively.

	Discussion

Top Abstract Introduction Materials and methods Results Discussion References

 
This study shows how systematic radiation-attenuating techniques enabled us to reduce mean DAPs far below typical values for CA, coronary angioplasties and recanalizations, high-frequency rotablation atherectomy, and excimer laser angioplasty (Figure 1).

The first publication of warnings on the serious effects of X-rays on tissue appeared as long ago as 1896. These were followed by recommendations for investigation of possible pathological effects, the appearance of which was strangely delayed to a period long after radiation exposure [17]. As early as 1925, the following factors were summarized as playing deleterious roles in conjunction with X-ray applications for accidents and injuries: excessively long fluoroscopic examinations, short focus-skin distances, insufficient filtering of the X-ray beam, and – not least – excessive numbers of radiographs made by insufficiently trained operators and assistants [18].

Despite pulsed fluoroscopy, gap filling, improved image intensifiers and technical advances in digital spot radiation, exposure from coronary interventions remains high [19]. As routinely performed, cardiac catheterization currently delivers a mean DAP of 61.7±27.5 Gy cm² to the patient [1–9], equivalent to an effective dose of approximately 12.3±5.5 mSv [2, 15, 16]. The severity of this exposure is evident from the fact that 10 mSv is equivalent to 200 to 500 chest X-rays [20]. A DAP of 100 Gy cm², applied in one constant tube angulation during coronary intervention, will induce calculated skin entrance doses of about 1.6 Gy and 2.7 Gy for work with 17 cm and 13 cm intensifier loops, respectively.

Such levels may be easily reached during complex procedures (Figure 1): real-time studies of skin radiation have disclosed approximately 1.0 Gy to 2.5 Gy for coronary interventions [21], with 13.5% of the patients receiving a maximum dose of >2.0 Gy [5]. Acute radiation doses may cause erythema and cataract at 2 Gy, permanent epilation at 7 Gy, and delayed skin necrosis at 12 Gy [22]. Indeed, skin ulcerations have occurred following entrance doses of 16 Gy to 18 Gy during complex PTCA with fluoroscopy periods up to 40 min to 68 min, partly performed at high-level fluoro mode [12], which may induce excessive dose rates between 0.2 Gy min^-1 and 0.8 Gy min^-1 [23]. On the other hand, only 3 of 14 patients who underwent between 4 and 14 CAs and between 5 and 10 PTCAs over a period of 2 to 10 years, retrospectively, demonstrated only slight teleangiectasia and pigmentation [24]. Nevertheless, the additional individual stochastic lifetime cancer mortality risk of an effective dose of 1 Gy over the course of 40 years has been calculated as 5–11% [25–27]. Based on an effective dose of 20 mSv, predicted PTCA-induced cancer mortality risk was reported at 0.08%, analogous to PTCA in-hospital mortality rates [28].

Our efforts, conducted on the largest population investigated until now for incrementally enhanced radiation-dose reduction, resulted in obvious benefits. We have concluded that the most effective step towards dose reduction is avoidance of lengthy cinegraphic filming, both in our attitudes as well as in actual reality, and establishment of the conviction that digital documentation of short cinegraphic loops of one heart cycle length, repeated as often as necessary, will provide adequate visual impressions. However, bypass grafts, collateral pathways, or slow-flow phenomena should be adequately documented by longer series, since diagnostic information otherwise will be compromised. In the present study, the degree of diagnostic disagreement by a supervising senior cardiologist did not evidence a change for periods I and II, the latter under conditions of radiation dose-reduction techniques.

In our study, minimization of cinegraphic frames per CA, typically reported to lie within a range of 1013 to 2344 [7], from 543 to a mean of 193 (Table 1) enabled significant reduction of the mean cinegraphic DAP by 15.8 Gy cm². Moreover, we were easily able to reduce to one-third of normal levels the fluoroscopic dose proportion for CA and PTCA, by training interventionists in fluoroscopy-saving blind positioning, by systematic use of the low-level fluoroscopy mode, and by such techniques as restriction to the ostial region of interest during intubation of coronary arteries. Fluoroscopy time and DAP^F s^-1 due to PTCA were accordingly lower than reported elsewhere [1, 6, 7]. Furthermore, for a given data volume of 0.26 MB per cinegraphic frame with a matrix of 512² pixels, the resulting data volume for complete CA is approximately 50 MB, and approximately 37 MB for PTCA. In emergency cases, it is easy to transfer such data volumes within 80 s to 100 s from a peripheral catheterization laboratory to the next tertiary cardiac surgery referral centre, for further discussion online or over the phone.

In the present study, which included performance of elective PTCA, coronary recanalization, combined emergency intervention, high-frequency rotablator atherectomy, and excimer laser angioplasty in at least three different angulations, we achieved calculated mean local patient ESAKs that did not exceed 0.12 Gy, 0.19 Gy, 0.35 Gy, 0.30 Gy, and 0.25 Gy, respectively. Work on these levels will reliably prevent permanent skin radiation injury, even in case of repeated interventions. Nevertheless, patients should be encouraged to report skin abnormalities after fluoroscopy-guided procedures, and should be counselled for any risk of radiation-induced injury. Effective tools for such consultation include algorithms based on body mass index and body surface area, as well as data on radiation exposure from all types of coronary interventions investigated in this study.

Our analysis furthermore disclosed a number of helpful details. Overweight, for example, does not impede the optimization of interventional techniques. Efforts directed toward documentation of complex coronary artery disease, coronary collaterals, and indications for coronary artery bypass grafts significantly induce higher DAPs. Coronary recanalizations require greater field sizes than does PTCA, evidently as a result of attempts to visualize the coronary periphery and to prevent guide-wire exit.

Interventionalists should be aware of the high radiation intensity involved in documentation of the right coronary bifurcation at the crux. They should likewise perform PTCAs of the left anterior descending and diagonal arteries with only cranial posteroanterior views, rather than left anterior oblique angulation. For the same reason, they should favour caudal posteroanterior views over the caudal left anterior oblique spider view for documentation of the left main stem bifurcation.

In conclusion, this study enabled reduction of the patient's effective dose from elective CA under ALARA conditions to approximately 2.6 mSv, which is even lower than the effective dose levels of 2.8–12.7 mSv experienced under multislice-CT for coronary visualization [29]. However, the most effective technique for reducing medical exposure under radiodiagnostic circumstances to levels "as low as reasonably achievable" [14] remains being sure that the procedure is absolutely necessary.

Received for publication May 3, 2002. Revision received November 20, 2002. Accepted for publication April 9, 2003.

	References

Top Abstract Introduction Materials and methods Results Discussion References

 

1. Bakalyar DM, Castellani MD, Safian RD. Radiation exposure to patients undergoing diagnostic and interventional cardiac catheterization procedures. Cathet Cardiovasc Diagn 1997;42:121–5.[CrossRef][Medline]
2. Betsou S, Efstathopoulos EP, Katritsis D, Faulkner K, Panayiotakis G. Patient radiation doses during cardiac catheterization procedures. Br J Radiol 1998;71:634–9.[Abstract]
3. Clark AL, Brennan AG, Robertson LJ, McArthur JD. Factors affecting patient radiation exposure during routine coronary angiography in a tertiary referral centre. Br J Radiol 2000;73:184–9.[Abstract]
4. Cusma JT, Bell MR, Wondrow MA, Taubel JP, Holmes DR Jr. Real-time measurement of radiation exposure to patients during diagnostic coronary angiography and percutaneous interventional procedures. J Am Coll Cardiol 1999;33:427–35.[Abstract/Free Full Text]
5. den Boer A, de Feijter PJ, Serruys PW, Roelandt JR. Real-time quantification and display of skin radiation during coronary angiography and intervention. Circulation 2001;104:1779–84.[Abstract/Free Full Text]
6. Fransson SG, Persliden J. Patient radiation exposure during coronary angiography and intervention. Acta Radiol 2000;41:142–4.[CrossRef][Medline]
7. Lobotessi H, Karoussou A, Neofotistou V, Louisi A, Tsapaki V. Effective dose to a patient undergoing coronary angiography. Radiat Prot Dosim 2001;94:173–6.[Abstract]
8. Van de Putte S, Verhaegen F, Taeymans Y, Thierens H. Correlation of patient skin doses in cardiac interventional radiology with dose-area product. Br J Radiol 2000;73:504–13.[Abstract]
9. Zorzetto M, Bernardi G, Morocutti G, Fontanelli A. Radiation exposure to patients and operators during diagnostic catheterization and coronary angioplasty. Cathet Cardiovasc Diagn 1997;40:348–51.[CrossRef][Medline]
10. Bernardi G, Padovani R, Morocutti G, Vano E, Malisan MR, Rinuncini M, et al. Clinical and technical determinants of the complexity of percutaneous transluminal coronary angioplasty procedures: analysis in relation to radiation exposure parameters. Cathet Cardiovasc Interv 2000;51:1–9.[CrossRef][Medline]
11. Lichtenstein DA, Klapholz L, Vardy DA, Leichter I, Mosseri M, Klaus SN, et al. Chronic radiodermatitis following cardiac catheterization. Arch Dermatol 1996;132:663–7.[Abstract/Free Full Text]
12. Sovik E, Klow NE, Hellesnes J, et al. Radiation induced skin injury after percutaneous transluminal coronary angioplasty. Case report. Acta Radiol 1996;37:305–6.[Medline]
13. Vano E, Arranz L, Sastre JM, Moro C, Ledo A, Garate MT, et al. Dosimetric and radiation protection considerations based on some cases of patient skin injuries in interventional cardiology. Br J Radiol 1998;71:510–6.[Abstract]
14. CEC Council Directive 97/43/Euratom of 30 June 1997. Article 4: On health protection of individuals against the dangers of ionizing radiation in relation to medical exposure. Euratom Amtsblatt 1997;L180:22–7.
15. Hart D, Jones DG, Wall BF. Estimation of effective dose in diagnostic radiology from entrance surface dose and dose area product measurements. National Radiological Protection Board (NRBP-R 262), London: HMSO Publications Centre, 1994:1–57.
16. Leung KC, Martin CJ. Effective doses for coronary angiography. Br J Radiol 1996;69:426–31.[Abstract/Free Full Text]
17. Thomson E. Strong effects by X-rays on tissue. Electrical Engineering 1896;22:534.
18. Groedel FM, Lininger H, Lossen H. Materialsammlung der Unfälle und Schäden in Röntgenbetrieben. Hamburg, Germany: Lucas, Gräfe & Sillem Press, 1925.
19. Whiting JS. Recent technical advances in digital coronary angiography. Curr Opin Cardiol 1994;9:740–6.[CrossRef][Medline]
20. Announcement to the German Parliament by the German Federal Ministry for Environment, Natural Conservation, and Nuclear Safety, dated 10 September 2001; Letter No 14/6905:30.
21. Hwang E, Gaxiola E, Vlietstra RE, Brenner A, Ebersole D, Browne K. Real-time measurement of skin radiation during cardiac catheterization. Cathet Cardiovasc Diagn 1998;43:367–70.[CrossRef][Medline]
22. Valentin J. Avoidance of radiation injuries from medical interventional procedures. Ann ICRP 2000;30:7–67.
23. Cagnon CH, Benedict SH, Mankovich NJ, Bushberg JT, Seibert JA, Whiting JS. Exposure rates in high level control fluoroscopy for image enhancement. Radiology 1991;178:643–6.[Abstract/Free Full Text]
24. Vano E, Goicolea J, Galvan C, Gonzalez L, Meiggs L, Ten JI, et al. Skin radiation injuries in patients following repeated coronary angioplasty procedures. Br J Radiol 2001;74:1023–31.[Abstract/Free Full Text]
25. Committee on the Biological Effects of Ionizing Radiation. Health effects of exposure to low levels of ionizing radiation. BEIR V, National academy of sciences/National research council. Washington DC: National Academy Press, 1990.
26. Recommendations of the International Commission on Radiological Protection. ICRP Publication 60. Oxford: Pergamon Press, 1991:126,153,172.
27. United Nations Scientific Committee on the Effect of Atomic Radiation. Sources, effects and risks of ionizing radiation. Annex F. Radiation carcinogenesis in man. UNSCEAR report to the UN general assembly, United Nations. New York, 1988: E.88.IX.7.
28. Johns PC, Renaud L. Radiation risk associated with PTCA. Primary Cardiol 1994;20:27–31.
29. Cohnen M, Poll L, Puttmann C, Ewen K, Modder U. Radiation exposure in multi-slice of the heart. Rofo Fortschr Geb Rontgenstr Neuen Bildgeb Verfahr 2001;173:295–9.[Medline]

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