Journal of Pediatric Surgery xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Journal of Pediatric Surgery journal homepage: www.elsevier.com/locate/jpedsurg
Review of the radiation exposure during screening of surgically implanted central venous access devices Jikol Friend ⁎, Suzanna Lindsey-Temple, Ian Gollow, Elizabeth Whan, Parshotam Gera Departments of Pediatric General Surgery, Princess Margaret Hospital, Subiaco, Western Australia, Australia
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Article history: Received 18 December 2014 Received in revised form 20 March 2015 Accepted 22 April 2015 Available online xxxx Key words: Venous access device Pediatric Radiation exposure Effective dose Dose area product
a b s t r a c t Purpose: Ionizing radiation is used for the insertion of surgically implanted venous access devices (SIVADs) with children at the highest risk of cumulative radiation effects from these procedures. This study examines the radiation dose in a pediatric population during intraoperative radiological screening. Methods: A retrospective study looked at all pediatric patients in a tertiary hospital between January 2008 and January 2014 who had a surgically implanted venous access device inserted using intraoperative fluoroscopy. Patient demographics, reason for SIVAD insertion, the type and method of insertion, fluoroscopy time and radiation dose area product were determined. Results: A total of 505 patients had 682 SIVADs inserted, with 123 patients receiving multiple SIVAD over the six year period. There were two types of SIVAD inserted, 492 were totally implanted venous access devices (TIVAD) and 190 were tunneled central venous catheters (cuffed central line). Five hundred seven of the SIVAD inserted recorded the dose area product and fluoroscopy time. The median time for screening was 5 seconds (range 1 to 275 seconds) and the median dose area product was 0.00352 mGym 2 (range 0.000001 mGym2 to 0.28 mGym2). Of the 507 SIVAD that recorded the radiation data, 479 were open surgical cut-down insertion and 27 were percutaneous insertion. Percutaneously inserted surgically implanted venous access devices (mean 0.0060 mGym2) had a longer dose area product than open insertion (mean 0.0034 mGym2; p = 0.05). Conclusion: Screening of SIVAD involves low levels of radiation exposure and is comparable to a chest x-ray or a transatlantic flight. The excess lifetime cancer risk to patients is estimated to be very low and is considered to be outweighed by the benefits of insertion. Open surgical cut-down insertion has a significantly reduced radiation exposure compared to percutaneous techniques. Although radiation dose is higher with percutaneous procedures, the clinical effects are considered minimal, and the resultant radiation risk is estimated to be very low. Radiation dose should not determine technique of insertion of SIVAD. © 2015 Published by Elsevier Inc.
Fluoroscopic screening during the insertion of surgically implanted venous access devices (SIVAD) in pediatric patients is utilized to assess the position of the device, but exposes children to ionizing radiation. Ultrasound, transthoracic echocardiogram and intracavitary electrocardiogram have been reported to be safe techniques in recent literature [1,2] and have been introduced in Western Australia because of the perceived risks of exposing children to radiation. Pediatric patients have increased tissue radiosensitivity, increased time for cumulative radiation exposure and often a previous history of malignancy which increases their risk of radiation effects [3–5]. Previous research into pediatric computer tomography has raised concerns on radiation exposure and long term effects [5–8]. Although there has been recent a recent study by Storm and colleagues [9] of the radiology fluoroscopy time, cumulative dose and dose area product from 1010 instances of 6 different venous access procedures over a 6 year period in an adult population, ⁎ Corresponding author. Princess Margaret Hospital, Roberts Rd, Subiaco, Western Australia 6008, Australia. Tel.: +61 93133409; fax: +61 97321280. E-mail address: [email protected] (J. Friend).
the radiation doses during insertion of pediatric surgically implanted venous access devices is relatively unknown. Chida and colleagues [10] have also researched the relationship between fluoroscopic time and dose area product (DAP) in 200 consecutive adult cardiac intervention procedures and measured the patient skin dose, fluoroscopy time and dose area product. They concluded that DAP is the gold standard for recording radiation dose and that weight multiplied by fluoroscopic time should only be used if DAP cannot be recorded [10]. Although fluoroscopic time and DAP were recorded in our current study, DAP facilitates comparison to other procedures and can be used to calculate the effective dose. This allows for an estimate of the risk of radiation effects on the patient. 1. Methods A retrospective study of pediatric patients at a tertiary hospital in Perth, Western Australia between January 2008 and January 2014 was performed. All pediatric patients who had surgically implanted intravascular venous access devices inserted or repaired in theater using intraoperative fluoroscopy were identified using the theater database.
http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017 0022-3468/© 2015 Published by Elsevier Inc.
Please cite this article as: Friend J, et al, Review of the radiation exposure during screening of surgically implanted central venous access devices, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017
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J. Friend et al. / Journal of Pediatric Surgery xxx (2015) xxx–xxx
Intravascular devices placed by the Radiology Department were excluded, because they do not insert central venous access devices. The Radiology Department at this center inserts external lines which often do not require fluoroscopy because of minimal risk of great vessel injury and pneumothorax. Similarly venous access devices inserted by the Anaesthetic Departments were excluded at this center. All central lines inserted by anesthetists are temporary venous access devices which do not undergo fluoroscopy because they are not tunneled. The cases were reviewed to determine patient demographics (age and gender), the diagnosis requiring venous access device insertion, the type of device (tunneled central venous catheters or totally implanted venous access device) and the method of insertion (percutaneous or open technique). Preoperative ultrasound and intraoperative electrocardiogram monitoring were used in all cases to guide placement of surgically implanted venous access device. Percutaneous techniques involve using an ultrasound to identify the vein with the introduction of wire and catheter using Seldinger technique. Fluoroscopy is then used to confirm the position prior to fixation. Open technique involves a 10 mm supraclavicular incision and dissection between the two heads of sternocleidomastoid. Direct visualization and isolation of internal jugular vein allows for the open incision and threading of catheter. Fluoroscopy was then used to confirm the position of the catheter tip in all cases. Patients with fluoroscopy recorded on the hospital radiology system were reviewed to determine the fluoroscopy time and dose area product. This was used to calculate an effective dose which facilitates comparison with literature on radiation exposure in pediatric patients and to evaluate the risk of stochastic or deterministic radiation effects. Effective dose considers that different types of radiation produce different tissue effects and that some tissues and organs are more sensitive [3,11]. Effective dose is measured in Sieverts or Rems (100 rems = 1 Sv) and is calculated as follows: E¼
X
WT
T
E T WT WR DT,R
X
The most common reason for SIVAD insertion (Fig. 2) was malignancy (76.6%; 523/682), with acute lymphoblastic leukemia (ALL) making up the majority of the malignancy cases (18.6%; 127/682), followed by acute myelogenous leukemia (AML) (9.7%; 66/682), neuroblastoma (5.6%; 38/682), Ewings/primitive neuroectodermal tumor (PNET) family (5.3%; 36/682) and Wilms tumor (4.3%; 29/682)). Other reasons for SIVAD insertion included chronic infection requiring antibiotics (7.7%; 53/682), hematological conditions requiring blood transfusion or factor replacement (6%; 41/682), short bowel syndrome requiring total parental nutrition (3.8%; 26/682), seizure access for antiepileptic medication (2.2%; 15/682) and enzyme replacement (1.9%; 13/682). Screening times for SIVAD insertion varied with a median of 5 seconds (max = 275 seconds, min = 1 second) (Fig. 3a). The median dose area product (DAP) was 0.00352 mGym2 (min = 0.000001 mGym 2, maximum = 0.28 mGym 2) (Fig. 3b). Despite a significant range in the majority of surgically implanted venous access device screening, DAP fell within 1 and 10 μGym2 with no statistically significant difference between totally implanted venous access device (portacath) and tunneled central venous catheter (p N 0.05). A total of 492 central tunneled venous catheters and 109 totally implanted venous access devices (portacaths) were inserted. Four hundred seventy-nine (94.7%) open surgical cut-down insertion and twenty-seven (5.3%) percutaneous procedures had recorded fluoroscopy time and dose area product (Fig. 4). Percutaneously inserted surgically implanted venous access devices (0.0060 mGym2) had a statistically significant higher dose area product than open insertion (0.0034 mGym2; p = 0.05). Dose equivalent was calculated to facilitate comparison to other radiation sources (Fig. 5). The screening SIVAD at Princess Margaret Hospital has a similar radiation dose equivalent to diagnostic chest x-rays, the annual background dose of food and water, or a trans-Atlantic flight. 3. Discussion
W R DT;R
R
effective dose subscript for each time of radiation tissue weighting factor radiation weighting coefficient (1 for XR); and average absorbed dose to tissue [3,12]
The study was a retrospective review of prospectively collected data, which reduces bias. If data were not recorded in the hospital radiology system, hard notes were reviewed to confirm a procedure took place otherwise the patient was excluded. If a procedure had occurred but no fluoroscopy time or DAP was recorded, retrieval of these data is not possible (if not recorded at the time) and the patient was included in demographic and frequency of screening data, but excluded from review of fluoroscopy time and DAP. 2. Results A total of 682 SIVADs were inserted in the theater with radiological screening over the six year period. Of the total, 507 had recorded fluoroscopy time and dose area product. There were 505 pediatric patients in the study population, 123 of these patients underwent multiple screening procedures; 85 had two screening procedures, 24 patients had three screening procedures and 12 patients had four screening procedures and two patients had five screening procedures. Children under four years of age made up the majority of the patients (43.8%) who underwent SIVAD insertion (Fig. 1). Sixty percent of patients were male (male = 414, female = 268).
Surgically implanted venous access devices (SIVADs) are an indispensable tool in the management of acute and chronic disease in children [13]. The insertion of SIVAD in this tertiary hospital occurs in the operating theater with intraoperative fluoroscopic screening to confirm the position of the catheter. Fluoroscopic screening is used in the majority of patients to confirm the correct anatomical placement of venous access devices [1] although recently other techniques including ultrasound, transthoracic echocardiogram and intracavitary electrocardiogram have been introduced on the basis of recent literature [1,2]. Concerns have been raised in the last decade about safe use of radiation in pediatric patients motivating change to other techniques to confirm catheter placement [2], but in general the radiation dose from fluoroscopically guided venous access procedures has not been studied because of the clinical impression that the radiation dose is relatively low [9]. Pediatric patients are particularly vulnerable to radiation exposure because of their increased tissue radiosensitivity [3–5]. The increased tissue radiosensitivity is caused by their increased rate of cell proliferation, a higher number of future cell divisions and ongoing morphological and functional differentiation. It has been estimated that children are 2 to 10 times more radiosensitive than adults. Furthermore there is an inverse exponential relationship between estimated risks from radiation exposure and the age of exposure [4,14]. Younger children are more likely to require SIVAD insertion, with 44% of patients in the current study less than four years of age. Children are also at increased risk of cancer because of the likelihood of future radiological exposure and resultant cumulative radiation effects [3,4]. One hundred twenty-three of the 505 patients (24%) in the current study underwent multiple screening procedures leading to additional radiation exposure. Young males then are more likely to be exposed to radiation through screening but are less sensitive to radiation effects [4]. A male predominance for venous access device insertion was confirmed in the current
Please cite this article as: Friend J, et al, Review of the radiation exposure during screening of surgically implanted central venous access devices, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017
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Fig. 1. Age of insertion of surgically implanted venous access device.
Fig. 2. (a) Diagnosis requiring surgically implanted venous access device. (b) Hematological malignancy requiring surgically implanted venous access device. (c) Solid organ malignancy requiring surgically implanted venous access device.
study with males making up 60% of the SIVAD insertions. Ahmed and colleagues [4] report that the excess radiation risks are estimated at 1.4 case for males and 2.6 cases for females per 1000 for exposure at 10 years of age, and 1.8 cases for males and 3.3 cases for females per 1000 population at 5 years of age. It can be presumed that both gender and age affect radiosensitivity to stochastic effects. Patients receiving SIVAD are usually critically ill and require multiple radiological investigations increasing their cumulative exposure to radiation. There are several studies reviewing radiation exposure for particular pediatric groups at high risk of cumulative radiation, although not necessarily related to SIVAD insertion. Specific patient populations with chronic conditions or recurrent symptoms have been found to have high rates of repeat imaging, including those with Crohn's disease [15], cystic fibrosis [4] and renal colic [16]. Pediatric trauma patients are also frequently undergoing multiple radiologic studies during trauma evaluation and subsequent care [17], and oncology patients are particularly vulnerable [4]. The current study also suggests that pediatric patients with malignancy are critically ill and exposed to repeated doses of radiation during the insertion of multiple venous access devices. Critical illness and history of malignancy increase the effects of radiation as well as the likelihood of exposure to further radiation [4]. This is supported by our findings that 67% of pediatric patients requiring surgically implanted venous access device insertion had a malignancy. Survivors of malignancy are known to be at a greater risk of future malignancy than the background population with a relative risk of 14.8 of developing a second malignant neoplasm [4,18]. These children are also likely to undergo multiple exposures to diagnostic screening procedures (e.g., annual computed tomography scans), interventional radiology procedures and therapeutic treatments. Both chemotherapy and radiotherapy regimens are also thought to be significant contributors to the risk of malignancy [4,19]. As the survival rates for childhood malignancies continue to improve, 80% of pediatric patients with malignancy are expected to reach adulthood, the long term sequelae related to all aspects of diagnosis and management are of increasing importance [4]. International studies have reviewed exposure to radiation in oncology patients and raised concerns regarding frequent radiological procedures. Ahmed and colleagues [4] showed that a total of 4338 procedures involving ionizing radiation were performed on 150 pediatric patients over a five year study, with a median of 19.5 procedures per patient (range 2 to 109 procedures per patient). Patients with leukemia and brain tumors underwent the fewest procedures (median cumulative effective dose b12 mSv), while patients with neuroblastoma had the highest overall median cumulative effective dose (213 mSv), followed by lymphoma (191 mSv) [4].The current study suggests that although individual episodes of radiation exposure are low, cumulative radiation exposure can be significant and must be considered.
Please cite this article as: Friend J, et al, Review of the radiation exposure during screening of surgically implanted central venous access devices, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017
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Fig. 3. (a) Fluoroscopy time for screening of surgically implanted venous access device insertion. (b) Radiation dose area product (DAP) of surgically implanted venous access device insertion.
Screening surgically implanted venous access devices exposes children to x-ray beams which are a nonparticulate high energy penetrating form of ionizing radiation. These particles cause damage through direct absorption at a molecular level and indirect oxidative damage from reactive oxygen free radicals creating two types of biological effect deterministic and stochastic [3]. Deterministic effects are rarely seen in pediatric population from medical therapy or investigations and were not seen in this study. They occur at doses over a certain threshold and effects increase above this threshold [3]. The tissue destruction and cell loss effects tend to be immediate and recovery depends on the dose and exposure time [3].The dose effects result in partial body (local effects e.g. skin), full body (whole body effects) and acute radiation syndrome which affects hematopoietic, gastrointestinal and central nervous system [3]. Stochastic effects occur when cells are not killed but modified. Effects are not immediate and there is no definite threshold from which effects will occur. Rather it is probabilistic, an increased dose results in an increased probability of cancer but not an increase in the
degree of aggression [3,11]. There is no way to distinguish radiation induced cancer from other forms [4]. Although there are no longitudinal studies in a pediatric population following radiation dose to determine actual cancer risk, children have more time to accumulate exposures and damage and there is also more time after their exposure to develop the disease [4]. Exposure, absorbed radiation dose and effective dose are the main measures of radiation dose [20]. Exposure dose (roentgen, R) is the measure of radioactivity per unit of air, but does not express how much energy is being absorbed by the tissues being irradiated [3,20]. Absorbed radiation dose (Grays (1 Gy = 1 J/kg) or rads (100 rads = 1 Gy)) describes the amount of energy absorbed per unit mass at a specific point [3,20], but does not consider where the type of radiation is absorbed or reflect the relative radiosensitivity of the tissues. [3,20]. Effective dose equivalent (Sieverts or Rems (100 rems = 1 Sv)) considers that different types of radiation produce different tissue effects and that some tissues and organs are more sensitive [3,20].
Please cite this article as: Friend J, et al, Review of the radiation exposure during screening of surgically implanted central venous access devices, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017
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Fig. 4. Radiation dose area product of percutaneous compared to open insertion of surgically implanted venous access device.
Estimates of radiation exposure in clinical practice are difficult, using either fluoroscopy time and dose area product (DAP), a measure of the absorbed radiation (milligrays) that accounts for the area irradiated (meters squared) [10]. Fluoroscopy time is the factor that the Food and Drug administration (FDA) and the International Commission of Radiological Protection (ICRP) recommend be monitored during fluoroscopically guided intervention procedures [10,11]. The median fluoroscopy time for screening during insertion of surgically implanted venous access devices in the current study was 5 seconds but with a large range between 1 and 275 seconds. Chida and colleagues [10] found that the correlation of maximum radiation skin dose with DAP is more accurate than that with fluoroscopy time, recommending that DAP be recorded primarily and fluoroscopic time be recorded when DAP cannot be monitored. The current study found that the median dose area product for screening during surgically implanted venous access device insertions was 0.0035 mGym2 with a large range (0.000001 to 0.28 mGym 2). The potential biological effects of the radiation exposure to this pediatric population during SIVAD insertion can be drawn from several studies looking at computed tomography scans. Many studies have
shown a cancer risk to children exposed to low dose radiation levels comparable to helical computed tomography (CT) [6–8]. Brenner and Hall [8] showed that the relative radiation dose from an abdominal CT scan for a child is 1 to 1.5 × that of natural background radiation exposure (3.5 mSv per year) with approximately one fatal cancer for every 1000 CT scans performed in a young child [7,11]. There are however uncertainties about defining biological risks with no studies reporting reproducible “cut off” levels of radiation effective dose [7]. Brenner and colleagues [7] report that the lowest dose of x-ray or gamma radiation for which good evidence exists of increased cancer risk is 10 to 50 mSv for an acute exposure and 50 to 100 mSv for a protracted exposure. There is reasonable, though not definitive, epidemiological evidence that organ doses in the range of 5 to 125 mSv result in a very small but statistically significant increase in cancer risk [7,8]. If there is a standard 5% (1 in 20) per Sievert risk of cancer, then a 10 mSv exposure should result in a 0.05% (1 in 2000) risk of cancer, although this has not been adjusted for pediatric risks per Sievert [7,8]. Despite significant research into pediatric CT scans there are few studies on radiation doses from fluoroscopically guided venous access
Fig. 5. Comparison of radiation effective dose in surgically implanted venous access devices.
Please cite this article as: Friend J, et al, Review of the radiation exposure during screening of surgically implanted central venous access devices, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017
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procedures. Storm and colleagues [9] reviewed radiation doses from venous access procedures in adults and reported that no procedure yielded a cumulative dose of more than 950 mGy or a peak skin dose of more than 760 mGy. The study concluded that radiation doses from venous access procedures are low and even extreme outlier cases are unlikely to produce doses high enough to cause deterministic skin effects, although radiation doses from multiple procedures are cumulative and knowledge of the radiation dose and consideration of stochastic cancer effects are desirable [9]. The method of insertion affects the radiation dose. Recent studies have investigated shifting from open surgical cut-down to ultrasound guided percutaneous central venous catheterization [1]. The open procedures tend to have a lower dose area product (median DAP = 0.0034 mGym2) than percutaneous procedures (median DAP = 0.0060 mGym2). Percutaneously inserted surgically implanted venous access device are expected to have a higher radiation dose as intraoperative fluoroscopy is used to assess the position of the wire before proceeding to dilate the vein. However insertion of percutaneous venous access devices should not be contraindicated by the radiation exposure which is minimal regardless of technique. Radiation risks must be balanced with failure to cannulate the vein, arterial puncture, hemopneumothorax, pericardial tamponade and even death [1]. Long-term risks including infection, thrombosis and reoperation options reduced with insertion by percutaneous techniques should also be considered [1]. A recent study by Granziera et al. [21] of 796 adult cases of SIVAD insertion demonstrated that early complications were more common in blind percutaneous (35.4%) cases than open surgical cut-down (14.7%) although ultrasound guided percutaneous insertion (3.9%) is the safest (p value of b0.001). When late complications were considered open surgical cut-down had the greatest number of complications (13.7%), followed by blind percutaneous insertion (6.2%), the safest being ultrasound guided percutaneous insertion (4%) [21]. In Western Australia percutaneous lines are increasingly being inserted because of ease of repeat line placement, however in patients with variable anatomy and multiple lines, individual surgeons operate within their area of skill and comfort, so there is a higher rate of open surgical cut-down. In a systemic review and meta-analysis by Orci et al. [22] no significant difference over all was found between thrombosis, infection and catheter migration in open cut-down or percutaneous techniques. This study concluded that improved primary insertion rates were noted in percutaneous techniques but that pneumothorax which can be lifethreatening develops only in relation to percutaneous puncture. The current study also demonstrates that when radiation exposure is considered open surgical cut-down has significantly smaller radiation doses than percutaneous insertion. However the radiation exposures were mostly recorded between 0.01 and 0.001 mGym 2, with all SIVAD insertion doses having a total of less than 1 mSv. Based on other studies, this dosage indicates a very low potential for radiation harm, regardless of technique of insertion. Therefore radiation exposure should not affect the choice for percutaneous or open surgical cut-down techniques of insertion of SIVAD. Both nuclear medicine and interventional radiology support using the lowest dose of radiation to gain diagnostic information with the principle of As Low As Reasonably Achievable (ALARA) [5]. However the risk of radiation must be balanced against confident placement of the SIVAD. The current study demonstrates that the screening of surgically implanted venous access devices in pediatric patients at Western Australia's pediatric hospital is equivalent to a chest x-ray or trans-Atlantic flight. This study has several key limitations including that the risks are extrapolated from previous radiation exposure papers. Ideally a prospective long-term study following patients with exposure to radiation during surgically implanted central venous access device insertion would allow a more accurate assessment of the risk of radiation. However this would be affected by exposure to radiation during other investigation, intervention and treatment exposures as well as difficulty identifying if subsequent malignancy is related to the initial insult or the
surgically implanted venous access device radiation screening. Finally this study has not measured the radiation doses patients are exposed to during other investigations, interventions and treatments which may greatly affect their risk of future stochastic effects. Further research is required into cumulative radiation exposure for these vulnerable pediatric populations to allow for a more accurate assessment of radiation risks. 4. Conclusion While radiation exposure and cumulative exposure are certainly a consideration in pediatric patients receiving surgically implanted central venous access devices, when converted to the effective dose, the screening of surgically implanted venous access devices exposes most pediatric patients in this tertiary hospital to a dose of less than 1 mSv which is approximately equivalent to a diagnostic chest x-ray or a trans-Atlantic flight. Furthermore although percutaneous insertion exposes patients to slightly higher doses of radiation, the exposure is minimal in clinical context and should not determine method of insertion. This allows a more accurate risk assessment for the surgeon when inserting central venous access device and assists in determining the risk for repeating screening in the insertion of a difficult venous access device. References [1] Avanzini S, Guida E, Conte M, et al. Shifting from open surgical cut down to ultrasound percutaneous central venous catheterization in children: learning curve and related complications. Pediatr Surg Int 2010;26:819–24. [2] Pittiruti M, La Greca A, Scoppettuolo G. The intracavitary echocardiographic method for positioning the tip of central venous catheters: results of an Italian multicenter study'. J Vasc Access 2012;13(3):357–65. [3] Allen JY, Endom EE. Clinical features of radiation exposure in children. www. uptodate.com. [viewed Jan 2013 and March 2014]. [4] Ahmed BA, Connolly BL, Shroff P, et al. Cumulative effective doses from radiologic procedures for pediatric oncology patients. Pediatrics 2010;126:p851–8. [5] Frush D. CT dose and risk estimates in children. Pediatr Radiol 2011;41(Suppl. 2):483–7. [6] Pierce DA, Preston DL. Radiation related cancer risks at low doses among atomic bomb survivors. Radiat Res 2000;154:p178–86. [7] Brenner DJ, Doll R, Goodhead DT, et al. Cancer risks attributable to low dose of ionizing radiation assessing what we really know. Proc Natl Acad Sci U S A 2003;100(24):13761–6. [8] Brenner DJ, Hall EJ. Computer tomography: an increasing source of radiation exposure. N Engl J Med 2007;357:2277–84. [9] Storm E, Miller D, Hoover LJ, et al. Radiation doses from venous access procedures. Radiology 2006;238(3):1044–50. [10] Chida K, Saito H, Otani H, et al. Relationship between fluoroscopic time, dose area product, body weight and maximum radiation skin dose in cardiac interventional procedures. Am J Radiol 2006:744–78. [11] National Research Council of the National Academies. Committee to assess health risks from exposure to low levels of ionizing radiation. BEIR VII Phase 2. Washington DC: National Academies Press; 2009. [12] Schultz FW, Zoetelief J. Dose conversion coefficients for interventional procedures. Radiat Prot Dosim 2005;117(1–3):225–30. [13] Schoot RA, Van Dalen EC, Van Ommen CH, van de Wetering MD. Antibiotic and other lock treatments for tunnelled central venous catheter-related infections in children with cancer. Cochrane Database Syst Rev 2013(6):1–50. http://dx.doi.org/10.1002/ 14651858.CD008975.pub2 [CD008975]. [14] Sodickson A, Baeyens PF, Andrriole KP, et al. Recurrent CT, cumulative radiation exposure and associated radiation-induced cancer risks from CT of adults. Radiology 2009;251(1):176–84. [15] Fuchs Y, Markowitz J, Weinstein T, et al. Pediatric inflammatory bowel disease and imaging related radiation: are we increasing the likelihood of malignancy. Gastroenterol JPGN 2011;52(3):280–5. [16] Katz SI, Saluja S, Brink JA, et al. Radiation dose associated with unenhanced CT for suspected renal colic impact of repetitive studies. AJR Am J Roentgenol 2006;186 (4):1120–4. [17] Kim PK, Zhu Z, Houseknecht E, et al. Effective radiation dose from radiologic studies in pediatric trauma patients. World J Surg 2005;29:1557–62. [18] Oeffinger KC, Mertens AC, Skiar CA, et al. Chronic health conditions in adult survivors of childhood cancer. N Engl J Med 2006;355(15):1572–82. [19] Bhatia S, Robinson LL, Oberlin O, et al. Breast cancer and other second neoplasm after childhood Hodgkins disease. N Engl J Med 1996;334(12):745–51. [20] McNitt Gray MF. AAPM/RSNA: physics tutorial for residents: topics in CT, radiation dose in CT. Imaging Ther Technol 2002;22(6):1541–53. [21] Granziera E, Scarpa M, Ciccarese A. Totally implantable venous access devices. Retrospective analysis of different insertion techniques and predictors of complications in 796 devices implanted in a single institution. BMC Surg 2014;14:14–27. [22] Orci LA, Meier RPH, Morel P, et al. Systemic review and metaanalysis of percutaneous subclavian vein puncture versus surgical venous cutdown and insertion of a totally implantable venous access device. Br J Surg 2014;101:8–16.
Please cite this article as: Friend J, et al, Review of the radiation exposure during screening of surgically implanted central venous access devices, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017
Contents lists available at ScienceDirect
Journal of Pediatric Surgery journal homepage: www.elsevier.com/locate/jpedsurg
Review of the radiation exposure during screening of surgically implanted central venous access devices Jikol Friend ⁎, Suzanna Lindsey-Temple, Ian Gollow, Elizabeth Whan, Parshotam Gera Departments of Pediatric General Surgery, Princess Margaret Hospital, Subiaco, Western Australia, Australia
a r t i c l e
i n f o
Article history: Received 18 December 2014 Received in revised form 20 March 2015 Accepted 22 April 2015 Available online xxxx Key words: Venous access device Pediatric Radiation exposure Effective dose Dose area product
a b s t r a c t Purpose: Ionizing radiation is used for the insertion of surgically implanted venous access devices (SIVADs) with children at the highest risk of cumulative radiation effects from these procedures. This study examines the radiation dose in a pediatric population during intraoperative radiological screening. Methods: A retrospective study looked at all pediatric patients in a tertiary hospital between January 2008 and January 2014 who had a surgically implanted venous access device inserted using intraoperative fluoroscopy. Patient demographics, reason for SIVAD insertion, the type and method of insertion, fluoroscopy time and radiation dose area product were determined. Results: A total of 505 patients had 682 SIVADs inserted, with 123 patients receiving multiple SIVAD over the six year period. There were two types of SIVAD inserted, 492 were totally implanted venous access devices (TIVAD) and 190 were tunneled central venous catheters (cuffed central line). Five hundred seven of the SIVAD inserted recorded the dose area product and fluoroscopy time. The median time for screening was 5 seconds (range 1 to 275 seconds) and the median dose area product was 0.00352 mGym 2 (range 0.000001 mGym2 to 0.28 mGym2). Of the 507 SIVAD that recorded the radiation data, 479 were open surgical cut-down insertion and 27 were percutaneous insertion. Percutaneously inserted surgically implanted venous access devices (mean 0.0060 mGym2) had a longer dose area product than open insertion (mean 0.0034 mGym2; p = 0.05). Conclusion: Screening of SIVAD involves low levels of radiation exposure and is comparable to a chest x-ray or a transatlantic flight. The excess lifetime cancer risk to patients is estimated to be very low and is considered to be outweighed by the benefits of insertion. Open surgical cut-down insertion has a significantly reduced radiation exposure compared to percutaneous techniques. Although radiation dose is higher with percutaneous procedures, the clinical effects are considered minimal, and the resultant radiation risk is estimated to be very low. Radiation dose should not determine technique of insertion of SIVAD. © 2015 Published by Elsevier Inc.
Fluoroscopic screening during the insertion of surgically implanted venous access devices (SIVAD) in pediatric patients is utilized to assess the position of the device, but exposes children to ionizing radiation. Ultrasound, transthoracic echocardiogram and intracavitary electrocardiogram have been reported to be safe techniques in recent literature [1,2] and have been introduced in Western Australia because of the perceived risks of exposing children to radiation. Pediatric patients have increased tissue radiosensitivity, increased time for cumulative radiation exposure and often a previous history of malignancy which increases their risk of radiation effects [3–5]. Previous research into pediatric computer tomography has raised concerns on radiation exposure and long term effects [5–8]. Although there has been recent a recent study by Storm and colleagues [9] of the radiology fluoroscopy time, cumulative dose and dose area product from 1010 instances of 6 different venous access procedures over a 6 year period in an adult population, ⁎ Corresponding author. Princess Margaret Hospital, Roberts Rd, Subiaco, Western Australia 6008, Australia. Tel.: +61 93133409; fax: +61 97321280. E-mail address: [email protected] (J. Friend).
the radiation doses during insertion of pediatric surgically implanted venous access devices is relatively unknown. Chida and colleagues [10] have also researched the relationship between fluoroscopic time and dose area product (DAP) in 200 consecutive adult cardiac intervention procedures and measured the patient skin dose, fluoroscopy time and dose area product. They concluded that DAP is the gold standard for recording radiation dose and that weight multiplied by fluoroscopic time should only be used if DAP cannot be recorded [10]. Although fluoroscopic time and DAP were recorded in our current study, DAP facilitates comparison to other procedures and can be used to calculate the effective dose. This allows for an estimate of the risk of radiation effects on the patient. 1. Methods A retrospective study of pediatric patients at a tertiary hospital in Perth, Western Australia between January 2008 and January 2014 was performed. All pediatric patients who had surgically implanted intravascular venous access devices inserted or repaired in theater using intraoperative fluoroscopy were identified using the theater database.
http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017 0022-3468/© 2015 Published by Elsevier Inc.
Please cite this article as: Friend J, et al, Review of the radiation exposure during screening of surgically implanted central venous access devices, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017
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Intravascular devices placed by the Radiology Department were excluded, because they do not insert central venous access devices. The Radiology Department at this center inserts external lines which often do not require fluoroscopy because of minimal risk of great vessel injury and pneumothorax. Similarly venous access devices inserted by the Anaesthetic Departments were excluded at this center. All central lines inserted by anesthetists are temporary venous access devices which do not undergo fluoroscopy because they are not tunneled. The cases were reviewed to determine patient demographics (age and gender), the diagnosis requiring venous access device insertion, the type of device (tunneled central venous catheters or totally implanted venous access device) and the method of insertion (percutaneous or open technique). Preoperative ultrasound and intraoperative electrocardiogram monitoring were used in all cases to guide placement of surgically implanted venous access device. Percutaneous techniques involve using an ultrasound to identify the vein with the introduction of wire and catheter using Seldinger technique. Fluoroscopy is then used to confirm the position prior to fixation. Open technique involves a 10 mm supraclavicular incision and dissection between the two heads of sternocleidomastoid. Direct visualization and isolation of internal jugular vein allows for the open incision and threading of catheter. Fluoroscopy was then used to confirm the position of the catheter tip in all cases. Patients with fluoroscopy recorded on the hospital radiology system were reviewed to determine the fluoroscopy time and dose area product. This was used to calculate an effective dose which facilitates comparison with literature on radiation exposure in pediatric patients and to evaluate the risk of stochastic or deterministic radiation effects. Effective dose considers that different types of radiation produce different tissue effects and that some tissues and organs are more sensitive [3,11]. Effective dose is measured in Sieverts or Rems (100 rems = 1 Sv) and is calculated as follows: E¼
X
WT
T
E T WT WR DT,R
X
The most common reason for SIVAD insertion (Fig. 2) was malignancy (76.6%; 523/682), with acute lymphoblastic leukemia (ALL) making up the majority of the malignancy cases (18.6%; 127/682), followed by acute myelogenous leukemia (AML) (9.7%; 66/682), neuroblastoma (5.6%; 38/682), Ewings/primitive neuroectodermal tumor (PNET) family (5.3%; 36/682) and Wilms tumor (4.3%; 29/682)). Other reasons for SIVAD insertion included chronic infection requiring antibiotics (7.7%; 53/682), hematological conditions requiring blood transfusion or factor replacement (6%; 41/682), short bowel syndrome requiring total parental nutrition (3.8%; 26/682), seizure access for antiepileptic medication (2.2%; 15/682) and enzyme replacement (1.9%; 13/682). Screening times for SIVAD insertion varied with a median of 5 seconds (max = 275 seconds, min = 1 second) (Fig. 3a). The median dose area product (DAP) was 0.00352 mGym2 (min = 0.000001 mGym 2, maximum = 0.28 mGym 2) (Fig. 3b). Despite a significant range in the majority of surgically implanted venous access device screening, DAP fell within 1 and 10 μGym2 with no statistically significant difference between totally implanted venous access device (portacath) and tunneled central venous catheter (p N 0.05). A total of 492 central tunneled venous catheters and 109 totally implanted venous access devices (portacaths) were inserted. Four hundred seventy-nine (94.7%) open surgical cut-down insertion and twenty-seven (5.3%) percutaneous procedures had recorded fluoroscopy time and dose area product (Fig. 4). Percutaneously inserted surgically implanted venous access devices (0.0060 mGym2) had a statistically significant higher dose area product than open insertion (0.0034 mGym2; p = 0.05). Dose equivalent was calculated to facilitate comparison to other radiation sources (Fig. 5). The screening SIVAD at Princess Margaret Hospital has a similar radiation dose equivalent to diagnostic chest x-rays, the annual background dose of food and water, or a trans-Atlantic flight. 3. Discussion
W R DT;R
R
effective dose subscript for each time of radiation tissue weighting factor radiation weighting coefficient (1 for XR); and average absorbed dose to tissue [3,12]
The study was a retrospective review of prospectively collected data, which reduces bias. If data were not recorded in the hospital radiology system, hard notes were reviewed to confirm a procedure took place otherwise the patient was excluded. If a procedure had occurred but no fluoroscopy time or DAP was recorded, retrieval of these data is not possible (if not recorded at the time) and the patient was included in demographic and frequency of screening data, but excluded from review of fluoroscopy time and DAP. 2. Results A total of 682 SIVADs were inserted in the theater with radiological screening over the six year period. Of the total, 507 had recorded fluoroscopy time and dose area product. There were 505 pediatric patients in the study population, 123 of these patients underwent multiple screening procedures; 85 had two screening procedures, 24 patients had three screening procedures and 12 patients had four screening procedures and two patients had five screening procedures. Children under four years of age made up the majority of the patients (43.8%) who underwent SIVAD insertion (Fig. 1). Sixty percent of patients were male (male = 414, female = 268).
Surgically implanted venous access devices (SIVADs) are an indispensable tool in the management of acute and chronic disease in children [13]. The insertion of SIVAD in this tertiary hospital occurs in the operating theater with intraoperative fluoroscopic screening to confirm the position of the catheter. Fluoroscopic screening is used in the majority of patients to confirm the correct anatomical placement of venous access devices [1] although recently other techniques including ultrasound, transthoracic echocardiogram and intracavitary electrocardiogram have been introduced on the basis of recent literature [1,2]. Concerns have been raised in the last decade about safe use of radiation in pediatric patients motivating change to other techniques to confirm catheter placement [2], but in general the radiation dose from fluoroscopically guided venous access procedures has not been studied because of the clinical impression that the radiation dose is relatively low [9]. Pediatric patients are particularly vulnerable to radiation exposure because of their increased tissue radiosensitivity [3–5]. The increased tissue radiosensitivity is caused by their increased rate of cell proliferation, a higher number of future cell divisions and ongoing morphological and functional differentiation. It has been estimated that children are 2 to 10 times more radiosensitive than adults. Furthermore there is an inverse exponential relationship between estimated risks from radiation exposure and the age of exposure [4,14]. Younger children are more likely to require SIVAD insertion, with 44% of patients in the current study less than four years of age. Children are also at increased risk of cancer because of the likelihood of future radiological exposure and resultant cumulative radiation effects [3,4]. One hundred twenty-three of the 505 patients (24%) in the current study underwent multiple screening procedures leading to additional radiation exposure. Young males then are more likely to be exposed to radiation through screening but are less sensitive to radiation effects [4]. A male predominance for venous access device insertion was confirmed in the current
Please cite this article as: Friend J, et al, Review of the radiation exposure during screening of surgically implanted central venous access devices, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017
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Fig. 1. Age of insertion of surgically implanted venous access device.
Fig. 2. (a) Diagnosis requiring surgically implanted venous access device. (b) Hematological malignancy requiring surgically implanted venous access device. (c) Solid organ malignancy requiring surgically implanted venous access device.
study with males making up 60% of the SIVAD insertions. Ahmed and colleagues [4] report that the excess radiation risks are estimated at 1.4 case for males and 2.6 cases for females per 1000 for exposure at 10 years of age, and 1.8 cases for males and 3.3 cases for females per 1000 population at 5 years of age. It can be presumed that both gender and age affect radiosensitivity to stochastic effects. Patients receiving SIVAD are usually critically ill and require multiple radiological investigations increasing their cumulative exposure to radiation. There are several studies reviewing radiation exposure for particular pediatric groups at high risk of cumulative radiation, although not necessarily related to SIVAD insertion. Specific patient populations with chronic conditions or recurrent symptoms have been found to have high rates of repeat imaging, including those with Crohn's disease [15], cystic fibrosis [4] and renal colic [16]. Pediatric trauma patients are also frequently undergoing multiple radiologic studies during trauma evaluation and subsequent care [17], and oncology patients are particularly vulnerable [4]. The current study also suggests that pediatric patients with malignancy are critically ill and exposed to repeated doses of radiation during the insertion of multiple venous access devices. Critical illness and history of malignancy increase the effects of radiation as well as the likelihood of exposure to further radiation [4]. This is supported by our findings that 67% of pediatric patients requiring surgically implanted venous access device insertion had a malignancy. Survivors of malignancy are known to be at a greater risk of future malignancy than the background population with a relative risk of 14.8 of developing a second malignant neoplasm [4,18]. These children are also likely to undergo multiple exposures to diagnostic screening procedures (e.g., annual computed tomography scans), interventional radiology procedures and therapeutic treatments. Both chemotherapy and radiotherapy regimens are also thought to be significant contributors to the risk of malignancy [4,19]. As the survival rates for childhood malignancies continue to improve, 80% of pediatric patients with malignancy are expected to reach adulthood, the long term sequelae related to all aspects of diagnosis and management are of increasing importance [4]. International studies have reviewed exposure to radiation in oncology patients and raised concerns regarding frequent radiological procedures. Ahmed and colleagues [4] showed that a total of 4338 procedures involving ionizing radiation were performed on 150 pediatric patients over a five year study, with a median of 19.5 procedures per patient (range 2 to 109 procedures per patient). Patients with leukemia and brain tumors underwent the fewest procedures (median cumulative effective dose b12 mSv), while patients with neuroblastoma had the highest overall median cumulative effective dose (213 mSv), followed by lymphoma (191 mSv) [4].The current study suggests that although individual episodes of radiation exposure are low, cumulative radiation exposure can be significant and must be considered.
Please cite this article as: Friend J, et al, Review of the radiation exposure during screening of surgically implanted central venous access devices, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017
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Fig. 3. (a) Fluoroscopy time for screening of surgically implanted venous access device insertion. (b) Radiation dose area product (DAP) of surgically implanted venous access device insertion.
Screening surgically implanted venous access devices exposes children to x-ray beams which are a nonparticulate high energy penetrating form of ionizing radiation. These particles cause damage through direct absorption at a molecular level and indirect oxidative damage from reactive oxygen free radicals creating two types of biological effect deterministic and stochastic [3]. Deterministic effects are rarely seen in pediatric population from medical therapy or investigations and were not seen in this study. They occur at doses over a certain threshold and effects increase above this threshold [3]. The tissue destruction and cell loss effects tend to be immediate and recovery depends on the dose and exposure time [3].The dose effects result in partial body (local effects e.g. skin), full body (whole body effects) and acute radiation syndrome which affects hematopoietic, gastrointestinal and central nervous system [3]. Stochastic effects occur when cells are not killed but modified. Effects are not immediate and there is no definite threshold from which effects will occur. Rather it is probabilistic, an increased dose results in an increased probability of cancer but not an increase in the
degree of aggression [3,11]. There is no way to distinguish radiation induced cancer from other forms [4]. Although there are no longitudinal studies in a pediatric population following radiation dose to determine actual cancer risk, children have more time to accumulate exposures and damage and there is also more time after their exposure to develop the disease [4]. Exposure, absorbed radiation dose and effective dose are the main measures of radiation dose [20]. Exposure dose (roentgen, R) is the measure of radioactivity per unit of air, but does not express how much energy is being absorbed by the tissues being irradiated [3,20]. Absorbed radiation dose (Grays (1 Gy = 1 J/kg) or rads (100 rads = 1 Gy)) describes the amount of energy absorbed per unit mass at a specific point [3,20], but does not consider where the type of radiation is absorbed or reflect the relative radiosensitivity of the tissues. [3,20]. Effective dose equivalent (Sieverts or Rems (100 rems = 1 Sv)) considers that different types of radiation produce different tissue effects and that some tissues and organs are more sensitive [3,20].
Please cite this article as: Friend J, et al, Review of the radiation exposure during screening of surgically implanted central venous access devices, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017
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Fig. 4. Radiation dose area product of percutaneous compared to open insertion of surgically implanted venous access device.
Estimates of radiation exposure in clinical practice are difficult, using either fluoroscopy time and dose area product (DAP), a measure of the absorbed radiation (milligrays) that accounts for the area irradiated (meters squared) [10]. Fluoroscopy time is the factor that the Food and Drug administration (FDA) and the International Commission of Radiological Protection (ICRP) recommend be monitored during fluoroscopically guided intervention procedures [10,11]. The median fluoroscopy time for screening during insertion of surgically implanted venous access devices in the current study was 5 seconds but with a large range between 1 and 275 seconds. Chida and colleagues [10] found that the correlation of maximum radiation skin dose with DAP is more accurate than that with fluoroscopy time, recommending that DAP be recorded primarily and fluoroscopic time be recorded when DAP cannot be monitored. The current study found that the median dose area product for screening during surgically implanted venous access device insertions was 0.0035 mGym2 with a large range (0.000001 to 0.28 mGym 2). The potential biological effects of the radiation exposure to this pediatric population during SIVAD insertion can be drawn from several studies looking at computed tomography scans. Many studies have
shown a cancer risk to children exposed to low dose radiation levels comparable to helical computed tomography (CT) [6–8]. Brenner and Hall [8] showed that the relative radiation dose from an abdominal CT scan for a child is 1 to 1.5 × that of natural background radiation exposure (3.5 mSv per year) with approximately one fatal cancer for every 1000 CT scans performed in a young child [7,11]. There are however uncertainties about defining biological risks with no studies reporting reproducible “cut off” levels of radiation effective dose [7]. Brenner and colleagues [7] report that the lowest dose of x-ray or gamma radiation for which good evidence exists of increased cancer risk is 10 to 50 mSv for an acute exposure and 50 to 100 mSv for a protracted exposure. There is reasonable, though not definitive, epidemiological evidence that organ doses in the range of 5 to 125 mSv result in a very small but statistically significant increase in cancer risk [7,8]. If there is a standard 5% (1 in 20) per Sievert risk of cancer, then a 10 mSv exposure should result in a 0.05% (1 in 2000) risk of cancer, although this has not been adjusted for pediatric risks per Sievert [7,8]. Despite significant research into pediatric CT scans there are few studies on radiation doses from fluoroscopically guided venous access
Fig. 5. Comparison of radiation effective dose in surgically implanted venous access devices.
Please cite this article as: Friend J, et al, Review of the radiation exposure during screening of surgically implanted central venous access devices, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017
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procedures. Storm and colleagues [9] reviewed radiation doses from venous access procedures in adults and reported that no procedure yielded a cumulative dose of more than 950 mGy or a peak skin dose of more than 760 mGy. The study concluded that radiation doses from venous access procedures are low and even extreme outlier cases are unlikely to produce doses high enough to cause deterministic skin effects, although radiation doses from multiple procedures are cumulative and knowledge of the radiation dose and consideration of stochastic cancer effects are desirable [9]. The method of insertion affects the radiation dose. Recent studies have investigated shifting from open surgical cut-down to ultrasound guided percutaneous central venous catheterization [1]. The open procedures tend to have a lower dose area product (median DAP = 0.0034 mGym2) than percutaneous procedures (median DAP = 0.0060 mGym2). Percutaneously inserted surgically implanted venous access device are expected to have a higher radiation dose as intraoperative fluoroscopy is used to assess the position of the wire before proceeding to dilate the vein. However insertion of percutaneous venous access devices should not be contraindicated by the radiation exposure which is minimal regardless of technique. Radiation risks must be balanced with failure to cannulate the vein, arterial puncture, hemopneumothorax, pericardial tamponade and even death [1]. Long-term risks including infection, thrombosis and reoperation options reduced with insertion by percutaneous techniques should also be considered [1]. A recent study by Granziera et al. [21] of 796 adult cases of SIVAD insertion demonstrated that early complications were more common in blind percutaneous (35.4%) cases than open surgical cut-down (14.7%) although ultrasound guided percutaneous insertion (3.9%) is the safest (p value of b0.001). When late complications were considered open surgical cut-down had the greatest number of complications (13.7%), followed by blind percutaneous insertion (6.2%), the safest being ultrasound guided percutaneous insertion (4%) [21]. In Western Australia percutaneous lines are increasingly being inserted because of ease of repeat line placement, however in patients with variable anatomy and multiple lines, individual surgeons operate within their area of skill and comfort, so there is a higher rate of open surgical cut-down. In a systemic review and meta-analysis by Orci et al. [22] no significant difference over all was found between thrombosis, infection and catheter migration in open cut-down or percutaneous techniques. This study concluded that improved primary insertion rates were noted in percutaneous techniques but that pneumothorax which can be lifethreatening develops only in relation to percutaneous puncture. The current study also demonstrates that when radiation exposure is considered open surgical cut-down has significantly smaller radiation doses than percutaneous insertion. However the radiation exposures were mostly recorded between 0.01 and 0.001 mGym 2, with all SIVAD insertion doses having a total of less than 1 mSv. Based on other studies, this dosage indicates a very low potential for radiation harm, regardless of technique of insertion. Therefore radiation exposure should not affect the choice for percutaneous or open surgical cut-down techniques of insertion of SIVAD. Both nuclear medicine and interventional radiology support using the lowest dose of radiation to gain diagnostic information with the principle of As Low As Reasonably Achievable (ALARA) [5]. However the risk of radiation must be balanced against confident placement of the SIVAD. The current study demonstrates that the screening of surgically implanted venous access devices in pediatric patients at Western Australia's pediatric hospital is equivalent to a chest x-ray or trans-Atlantic flight. This study has several key limitations including that the risks are extrapolated from previous radiation exposure papers. Ideally a prospective long-term study following patients with exposure to radiation during surgically implanted central venous access device insertion would allow a more accurate assessment of the risk of radiation. However this would be affected by exposure to radiation during other investigation, intervention and treatment exposures as well as difficulty identifying if subsequent malignancy is related to the initial insult or the
surgically implanted venous access device radiation screening. Finally this study has not measured the radiation doses patients are exposed to during other investigations, interventions and treatments which may greatly affect their risk of future stochastic effects. Further research is required into cumulative radiation exposure for these vulnerable pediatric populations to allow for a more accurate assessment of radiation risks. 4. Conclusion While radiation exposure and cumulative exposure are certainly a consideration in pediatric patients receiving surgically implanted central venous access devices, when converted to the effective dose, the screening of surgically implanted venous access devices exposes most pediatric patients in this tertiary hospital to a dose of less than 1 mSv which is approximately equivalent to a diagnostic chest x-ray or a trans-Atlantic flight. Furthermore although percutaneous insertion exposes patients to slightly higher doses of radiation, the exposure is minimal in clinical context and should not determine method of insertion. This allows a more accurate risk assessment for the surgeon when inserting central venous access device and assists in determining the risk for repeating screening in the insertion of a difficult venous access device. References [1] Avanzini S, Guida E, Conte M, et al. Shifting from open surgical cut down to ultrasound percutaneous central venous catheterization in children: learning curve and related complications. Pediatr Surg Int 2010;26:819–24. [2] Pittiruti M, La Greca A, Scoppettuolo G. The intracavitary echocardiographic method for positioning the tip of central venous catheters: results of an Italian multicenter study'. J Vasc Access 2012;13(3):357–65. [3] Allen JY, Endom EE. Clinical features of radiation exposure in children. www. uptodate.com. [viewed Jan 2013 and March 2014]. [4] Ahmed BA, Connolly BL, Shroff P, et al. Cumulative effective doses from radiologic procedures for pediatric oncology patients. Pediatrics 2010;126:p851–8. [5] Frush D. CT dose and risk estimates in children. Pediatr Radiol 2011;41(Suppl. 2):483–7. [6] Pierce DA, Preston DL. Radiation related cancer risks at low doses among atomic bomb survivors. Radiat Res 2000;154:p178–86. [7] Brenner DJ, Doll R, Goodhead DT, et al. Cancer risks attributable to low dose of ionizing radiation assessing what we really know. Proc Natl Acad Sci U S A 2003;100(24):13761–6. [8] Brenner DJ, Hall EJ. Computer tomography: an increasing source of radiation exposure. N Engl J Med 2007;357:2277–84. [9] Storm E, Miller D, Hoover LJ, et al. Radiation doses from venous access procedures. Radiology 2006;238(3):1044–50. [10] Chida K, Saito H, Otani H, et al. Relationship between fluoroscopic time, dose area product, body weight and maximum radiation skin dose in cardiac interventional procedures. Am J Radiol 2006:744–78. [11] National Research Council of the National Academies. Committee to assess health risks from exposure to low levels of ionizing radiation. BEIR VII Phase 2. Washington DC: National Academies Press; 2009. [12] Schultz FW, Zoetelief J. Dose conversion coefficients for interventional procedures. Radiat Prot Dosim 2005;117(1–3):225–30. [13] Schoot RA, Van Dalen EC, Van Ommen CH, van de Wetering MD. Antibiotic and other lock treatments for tunnelled central venous catheter-related infections in children with cancer. Cochrane Database Syst Rev 2013(6):1–50. http://dx.doi.org/10.1002/ 14651858.CD008975.pub2 [CD008975]. [14] Sodickson A, Baeyens PF, Andrriole KP, et al. Recurrent CT, cumulative radiation exposure and associated radiation-induced cancer risks from CT of adults. Radiology 2009;251(1):176–84. [15] Fuchs Y, Markowitz J, Weinstein T, et al. Pediatric inflammatory bowel disease and imaging related radiation: are we increasing the likelihood of malignancy. Gastroenterol JPGN 2011;52(3):280–5. [16] Katz SI, Saluja S, Brink JA, et al. Radiation dose associated with unenhanced CT for suspected renal colic impact of repetitive studies. AJR Am J Roentgenol 2006;186 (4):1120–4. [17] Kim PK, Zhu Z, Houseknecht E, et al. Effective radiation dose from radiologic studies in pediatric trauma patients. World J Surg 2005;29:1557–62. [18] Oeffinger KC, Mertens AC, Skiar CA, et al. Chronic health conditions in adult survivors of childhood cancer. N Engl J Med 2006;355(15):1572–82. [19] Bhatia S, Robinson LL, Oberlin O, et al. Breast cancer and other second neoplasm after childhood Hodgkins disease. N Engl J Med 1996;334(12):745–51. [20] McNitt Gray MF. AAPM/RSNA: physics tutorial for residents: topics in CT, radiation dose in CT. Imaging Ther Technol 2002;22(6):1541–53. [21] Granziera E, Scarpa M, Ciccarese A. 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Please cite this article as: Friend J, et al, Review of the radiation exposure during screening of surgically implanted central venous access devices, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.04.017
