International Atomic Energy Agency

Radiation risks in paedriatic Radiation risks in paedriatic interventional cardiologyinterventional cardiology

L 10

Lecture 10: Radiation risks in paediatric interventional cardiology 2Radiation Protection in Cardiology

Educational ObjectiveEducational Objective

1. Unique considerations in paediatric patients having bearing on patient dose

2. How can dose be managed in paediatric patients

Lecture 10: Radiation risks in paediatric interventional cardiology 3Radiation Protection in Cardiology

Unique Considerations for Radiation Exposure in Children

• There are two unique considerations in children:• Children are considerably more sensitive to radiation than adults• Children also have a longer life expectancy, resulting in a larger

window of opportunity for expressing radiation damage. • As an example, compared with a 40-year old, the same radiation

dose given to a neonate is several times more likely to produce a cancer over the child's lifetime.

• Great attention to not optimised procedures in CT examinations: • the same exposure parameters used for a child and an adult will result

in larger doses to the child• there is no need for these larger doses to children. Currently,

adjustments are not frequently made in the exposure parameters

Lecture 10: Radiation risks in paediatric interventional cardiology 4Radiation Protection in Cardiology

CT as a Diagnostic ToolIt will address the following issues:• CT as a diagnostic tool• Unique considerations for radiation• Radiation risks from CT in children: a public health issue• Immediate strategies to minimize CT radiation exposure to

children

Unique Considerations for Radiation Exposure in Children

Lecture 10: Radiation risks in paediatric interventional cardiology 5Radiation Protection in Cardiology

Risk probability for stochastic effects as a Risk probability for stochastic effects as a function of age at exposurefunction of age at exposure

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Age at Exposure

Death per Sievert

(Sv )

FemaleMale

Lecture 10: Radiation risks in paediatric interventional cardiology 6Radiation Protection in Cardiology

Epidemiology evidences (I)Epidemiology evidences (I)

Ionizing radiation and cancer risk: evidence from epidemiology Ron E. Radiat Res. 1998 Nov;150(5 Suppl):S30-41

• ….. For all solid cancers combined, cancers of the thyroid, breast and lung, and leukemia, risk estimates are fairly precise, and associations have been found at relatively low doses (<0.2 Gy).

• Associations between radiation and cancers of the salivary glands, stomach, colon, bladder, ovary, central nervous system and skin have also been reported, but the relationships are not as well quantified. …..

Lecture 10: Radiation risks in paediatric interventional cardiology 7Radiation Protection in Cardiology

Epidemiology evidences (II)Epidemiology evidences (II)Radiation-induced skin cancer in humans

Shore RE. Med Pediatr Oncol. 2001 May;36(5):549-54

• ... The Japanese atomic bomb study indicates that doses of radiation under about 1 Gy confer less risk per unit dose than higher doses do.

• … skin cancer risk is greater from radiation exposure at young ages than at older ages…...

• … available evidence indicates that the excess risk of skin cancer lasts for 45 years or more following irradiation …

Lecture 10: Radiation risks in paediatric interventional cardiology 8Radiation Protection in Cardiology

Epidemiology evidences (III)Epidemiology evidences (III)

• Cancer risks from medical radiationRon E. Health Phys. 2003 Jul;85(1):47-59

• Because doses from diagnostic examinations typically are low, they are difficult to study using epidemiological methods, unless multiple examinations are performed…

• An excess risk of breast cancer has been reported among women:• with tuberculosis who had multiple chest fluoroscopies• scoliosis patients who had frequent diagnostic x rays during

late childhood and adolescence.

Lecture 10: Radiation risks in paediatric interventional cardiology 9Radiation Protection in Cardiology

Frequency of cardiac intervention in Frequency of cardiac intervention in pediatricspediatrics

Spanish Registry on Cardiac Catheterization and Coronary Interventions. (1990-2002)]

Data from 101 centers …6 carried out only pediatric procedures. … a total increase of 5.1% in comparison to 2001.

• The population-adjusted rate: • 2,053 coronary angiograms per million inhabitants • 850 coronary interventions per million inhabitants

• Coronary interventions increased by 11% in comparison to 2001

• Stenting accounted for 91.7% of all procedures• Direct stenting was done in 13 768 procedures (43.2%).

Multivessel percutaneous in 9,830 patients (28%), and ad hoc interventions in 26,341 patients (76%).

• … and the slight increase in pediatric interventions (3.7%).

Lecture 10: Radiation risks in paediatric interventional cardiology 10Radiation Protection in Cardiology

Indications for interventions in pediatric cardiology

• Interventional catheterization in pediatric cardiology: tools and indications Boudjemline Y., Arch Pediatr. 2004 Mar;11(3):276-84.

• During the last decade, a remarkable number of transcatheter methods were developed:• balloon dilatation to treat vascular or valvular obstructive

lesions,• intravascular stents to manage obstructive lesions that

cannot be satisfactorily balloon-dilated, • transcatheter closure of atrial septal defects, patent

ductus arteriosus, • and ventricular septal defect. • More recently, pulmonary valve replacement has become

possible through a percutaneous technique

Lecture 10: Radiation risks in paediatric interventional cardiology 11Radiation Protection in Cardiology

Indications for interventions in pediatric cardiology

Future of interventional cardiology in pediatrics

Levi DS, Alejos JC, Moore JW. Curr Opin Cardiol. 2003 Mar;18(2):79-90.• A trend toward use of less invasive, non-surgical approaches to the treatment of congenital heart disease has developed• Additionally, fetal catheter-based interventions are being developed for the treatment of severe congenital heart disease in utero• Trend toward catheter-mediated treatment is certain to continue, care must be taken to regulate safely the introduction of novel techniques and devices into clinical use

Lecture 10: Radiation risks in paediatric interventional cardiology 12Radiation Protection in Cardiology

Radiation Exposure to Children Radiation Exposure to Children during during various interventionsvarious interventions (I)(I)

• Coil occlusion of the patent ductus arteriosus (PDA) as well as other more complex pediatric interventions has raised concern regarding radiation exposure

• No correlation between fluoroscopy time and measured entrance dose • Strongest correlation cumulative dose vs. patient weight and BSA

J. Donald Moore, David Shim, John Sweet, Kristopher L. Arheart and Robert H. Beekman III,Catheterization and Cardiovascular Interventions 47:449–454 (1999)David Shim, Thomas R. Kimball, Erik C. Michelfelder, Lisa Koons, RN and Robert H. Beekman, Catheterization and Cardiovascular Interventions 51:451–454 (2000)

Procedure No. patients

Fluoroscopy time (min)

Cine time (sec)

Total cumulative skin dose (mGy)

PDA 8 10.1 ±1.8 11.5±1.8 97±25PBV 5 19.3 ±2.3 10.9±2.3 86±32

Amplatzer 14 23.5 ±2.1 19.9±3.3 102±34DC 12 13.2 ±1.5 18.7±1.5 108±21

DC=diagnostic catheterization, PDA=Coil occlusion of the patent ductus arteriosus, PBV=pulmonary balloon valvuloplasty

Lecture 10: Radiation risks in paediatric interventional cardiology 13Radiation Protection in Cardiology

Radiation Exposure to Children Radiation Exposure to Children during during various interventionsvarious interventions (II)(II)

• Cumulative skin dose is well correlated with patient size and not with fluoroscopy time

Lecture 10: Radiation risks in paediatric interventional cardiology 14Radiation Protection in Cardiology

Radiation Exposure to Children Radiation Exposure to Children during during various interventionsvarious interventions (III)(III)

Comparison of surface entrance doses of radiation. A: Present study (Amplatzer atrial septal defect closure). B: Moore et al. [6] (patent ductus coil occlusion). C: Moore et al. [6] (pulmonary valvuloplasty). D: Wu et al. [8] (pulmonary valvuloplasty). E: Park et al. [10] (arhythmia ablation). F: Rosenthal et al. [11] (arhythmia ablation).

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Lecture 10: Radiation risks in paediatric interventional cardiology 15Radiation Protection in Cardiology

Occupational exposure in pediatric Occupational exposure in pediatric interventionsinterventions

• Although pediatric cardiologists have been performing cardiac catheterizations in infants and children for over 30 years, data regarding their occupational exposure are sparse

• Radiation exposure during arrhythmia ablation procedures in children, as measured by fluoroscopy duration, has been shown to be comparable to adults

Lecture 10: Radiation risks in paediatric interventional cardiology 16Radiation Protection in Cardiology

Summary Summary • Increased radiation risks for pediatric patients• Evidence of increased number of pediatric

interventional procedures• Radiation doses can be high• Very few dosimetric studies• Radiological technique must be optimised and

tailored to small body sizes:• Re-consider the need of antiscatter grid (doserate x 2)• Avoid electronic magnifications • Use collimations (reduce imparted energy, organ and

effective dose)• Image intensifier close to patient skin