Pulsed Fluoroscopy Research Articles

Prospective evaluation of radiation dose with conventional fluoroscopic voiding cystourethrogram in pediatric patients

Skin entrance doses for voiding cystourethrogram (VCUG) have not been well characterized in the literature. Radiation exposure is measured as either dose area product (DAP) or air kerma, which estimates the effective dose, but does not accurately reflect absorbed dose at skin level. The objective of this study was to measure the skin entrance dose during fluoroscopic VCUG study in pediatric patients using single point dosimeters. Pediatric patients undergoing fluoroscopic VCUG were prospectively enrolled in our study. Landauer NanoDot™OSLD dosimeters were affixed to the skin overlying the sacrum to measure skin entrance dose. The fluoroscopic unit was set to the following parameters: low dose setting, skin-to-source distance of 54cm, pulsed fluoroscopy at 3 frames/sec. Forty-four patients with a median age of 13.6 months (IQR 3.7-42.3) were enrolled. Median fluoroscopic time was 54s (IQR 36-72). The median values absorbed dose by dosimeter and air kerma were 0.32mGy (IQR 0.13-0.56, range 0.01-2.9) and 0.24mGy (IQR 0.14-0.37), respectively. There was a positive correlation between the air kerma and absorbed dose (r=0.69, p<0.001) and fluoroscopy time and absorbed dose mGy (r=0.60, p<0.001). Absorbed dose was independent of age, body mass index and body surface area (p=0.19, p=0.57 and p=0.16, respectively). Median whole body effective dose was 0.04mSv (IQR 0.02-0.7). Overall, the absorbed dose received by the dosimeter remained low at a median of 0.32mGy (range 0.01-2.91). These values are remarkably low and well within the accepted radiation exposure norms. Our radiologists follow a strict protocol to reduce the overall radiation emitted during a VCUG. These measures include setting the x-ray source at a low dose mode, collimating to the smallest area possible, and using pulsed fluoroscopy at 3 frames/sec. Limitations to this study include a slight variability in technique of VCUG between different technicians and providers, for which we cannot control. The radiation dose absorbed at the skin entrance and uniform whole body effective dose is low for a single VCUG when utilizing strict parameters. While newer non-ionizing technologies continue to emerge, our data is encouraging and will serve as a valuable tool when educating parents regarding radiation doses associated with a VCUG.

PD26-10 CORRELATION BETWEEN EXPOSURE OF ENDOUROLOGISTS AND PATIENT EXPOSURE DURING FLUOROSCOPY-GUIDED ENDOUROLOGICAL PROCEDURES

You have accessJournal of UrologyStone Disease: Surgical Therapy III (PD26)1 Sep 2021PD26-10 CORRELATION BETWEEN EXPOSURE OF ENDOUROLOGISTS AND PATIENT EXPOSURE DURING FLUOROSCOPY-GUIDED ENDOUROLOGICAL PROCEDURES Jenia Vassileva, Anna Zagorska, Sofia Bulgaria, Dragoslav Basic, Nis Serbia, Andreas Karagiannis, Kremena Petkova, Sofia Bulgaria, Kubilav Sabuncu, Ilya Saltirov, Sofia Bulgaria, Kemal Sarica, Andreas Skolarikos, Sotir Stavridis, Skopje Macedonia, Alberto Trinchieri, Lazaros Tzelves, Ismail Ulus, and Emrah Yuruk Jenia VassilevaJenia Vassileva More articles by this author , Anna ZagorskaAnna Zagorska More articles by this author , Sofia BulgariaSofia Bulgaria More articles by this author , Dragoslav BasicDragoslav Basic More articles by this author , Nis SerbiaNis Serbia More articles by this author , Andreas KaragiannisAndreas Karagiannis More articles by this author , Kremena PetkovaKremena Petkova More articles by this author , Sofia BulgariaSofia Bulgaria More articles by this author , Kubilav SabuncuKubilav Sabuncu More articles by this author , Ilya SaltirovIlya Saltirov More articles by this author , Sofia BulgariaSofia Bulgaria More articles by this author , Kemal SaricaKemal Sarica More articles by this author , Andreas SkolarikosAndreas Skolarikos More articles by this author , Sotir StavridisSotir Stavridis More articles by this author , Skopje MacedoniaSkopje Macedonia More articles by this author , Alberto TrinchieriAlberto Trinchieri More articles by this author , Lazaros TzelvesLazaros Tzelves More articles by this author , Ismail UlusIsmail Ulus More articles by this author , and Emrah YurukEmrah Yuruk More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002019.10AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Minimally invasive endourological procedures often need X-ray fluoroscopy guidance. Endourologists, may focus on their own exposure but underestimate the patient exposure. However, patient is exposed to primary X-ray beam, the intensity of which is much higher, compared to operator’s exposure from scattered radiation. This multicenter study of the South-Eastern European Group for Urolithiasis Research (SEGUR) aims to study radiation exposure of patients, during fluoroscopy guided endourological procedures in correlation withexposure factors and related staff radiation doses. METHODS: Seven clinical centers from the SEGUR group contributed to collection of relevant data for all standard percutaneous nephrolithotomy (PCNL), mini PCNL, retrograde intrarenal surgery (RIRS), semirigid ureterorenoscopy (URS) and flexible URS performed during a 3 month period, with paralell measurement of operators’ body and eye lens dose.The median total radiation dose in terms of dose area product (DAP) was calculated for every center and procedure, while fluoroscopy time, pulse rate and number of images were also recorded. Pearson’s correlation and chi-square/ Fisher’s exact tests, were used for statistical analysis, as appropriate. RESULTS: A strong correlation (r2 0.91-0.99) was found between endourologist eye dose and correponding total patient dose in terms of DAP. Reduced patient dose was associated with the use of lower pulse rate (12.5 pulse per second or lower), lower fluoroscopy time and lower number of recorded radiographic images. Lower dose in PCNL was associated with the use of prone compared to supine patient position. The highest patient dose was observed for a multiple access PCNL for kidney stone with pulsed fluoroscopy with 30 p/s, fluoroscopy time of 14 min and 156 recorded images. Dose values for RIRS were significantly lower compared to PCNL.No correlation was found between the concrement size and dose. Median patient exposure per center varied between 2 and 29-fold, with highest variations for the flexible and semi-rigid URS and lowest for RIRS, demonstrating a high potential for reduction of exposure of patients and urological team.Highest dose to patient skin from fluoroscopy was 377 mGy that is much below the dose treshold of 2 Gy needed to induce skin injury. CONCLUSIONS: Radiation exposure in patients during endourologic procedures, poses the risk of stochastic effects and increased cancer risk,which can be reduced by lowering patient dose through proper fluoroscopy. use. Source of Funding: Nothing to declare © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e441-e441 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Jenia Vassileva More articles by this author Anna Zagorska More articles by this author Sofia Bulgaria More articles by this author Dragoslav Basic More articles by this author Nis Serbia More articles by this author Andreas Karagiannis More articles by this author Kremena Petkova More articles by this author Sofia Bulgaria More articles by this author Kubilav Sabuncu More articles by this author Ilya Saltirov More articles by this author Sofia Bulgaria More articles by this author Kemal Sarica More articles by this author Andreas Skolarikos More articles by this author Sotir Stavridis More articles by this author Skopje Macedonia More articles by this author Alberto Trinchieri More articles by this author Lazaros Tzelves More articles by this author Ismail Ulus More articles by this author Emrah Yuruk More articles by this author Expand All Advertisement Loading ...

Radiation Dose Reduction in Congenital Heart Disease Patients During Cardiac Catheterization by a Novel Protocol.

Objective:Cardiac catheterization remains a major source of radiation exposure for patients with congenital heart disease. This study reports the magnitude of radiation with a 3.75 frame per second (fps) pulse fluoroscopy rate and compares the reduction with the previous 15 fps protocol during cardiac catheterization for pediatric and adult congenital heart disease.Material and Methods:All diagnostic and interventional cardiac catheterization procedures from a single tertiary center were analyzed from January 1, 2014 to December 31, 2015, one year before and after implementing lower starting pulse fluoroscopy rates. The radiation dose was quantified as air kerma dose (mGy) and dose-area product (DAP; µGy/m2). Radiation exposure was analyzed for diagnostic and interventional procedures; the diagnostic group was subdivided into cyanotic and acyanotic patients, whereas the interventional group was subdivided according to the most common indications.Results:A total of 786 procedures were analyzed. The median fluoroscopy times and contrast amounts did not show a statistically significant difference between both periods (487 vs. 456 seconds and 42.5 vs. 45.3 cm3). The median air kerma for all procedures showed an 88% reduction after implementing lower pulse fluoroscopy rates (340-41 mGy). The doses were reduced significantly for diagnostic and interventional angiograms from 470 mGy and 162 mGy to 40 mGy and154 mGy. Among all patient groups, the most striking decrease was observed in the diagnostic procedures we use, of which fluoroscopy is more prominent than cine angiography.Conclusion:We claim that novel radiation dose reduction protocols could be easily applied without increasing fluoroscopy time or losing image quality.

Pulsed fluoroscopy in retrograde urethrograms.

Retrograde urethrogram (RUG) is one of the corner stones for the reconstructive urologist. With hundreds of RUGs being performed yearly in busy reconstructive center, the concern for radiation exposure to the patient and the medical personnel becomes important. We propose the use of pulsed fluoroscopy to decrease the radiation exposure for patient and medical personnel. Patients presenting to our center with urethral strictures between March 2016 and March 2019 were included in our study. The fluoroscopy machine was set for pulsed fluoroscopy at a setting of 4 pulses per second. Patient information including demographics, pre-operative diagnosis, Intra-op findings, and fluoroscopy time were recorded. RUG was performed to localize the stricture pre-operatively and post-operatively. A total of 185 RUG were performed between March 2016 and March 2019. The median age was 63 (14-81). The remaining 154 RUG had 77 performed pre-operatively and 77 performed post-operatively. Pathology was identified in 77 patients. Intra-operative confirmation of pre-operative finding was found in 76 patients (98.7%). Median fluoroscopy time was found to be 2.43 seconds (0.5 sec- 6.5 sec). Pulsed fluoroscopy reduces the radiation exposure in RUG without a reduction in the diagnostic capacity of the test. Reduction of fluoroscopy can have beneficial cumulative effect as per the ALARA principle for patients and medical personnel. Further studies with randomized control trials could be of great benefit.

Abstract No. 537 Failure rates of pulse versus continuous fluoroscopy for the treatment of benign prostatic hyperplasia via prostatic artery embolization

Prostate artery embolization (PAE) often requires continuous fluoroscopy in order to visualize the arteries supplying the prostate and successfully embolize the vessels. Continuous fluoroscopy can expose the patient to high levels of radiation; therefore, usage of pulsed flow may provide for less radiation exposure. This study will aim to determine if pulsed flow results in higher failure rates compared to continuous flow at an outpatient-based laboratory. A total of 111 patients who underwent PAE for BPH treatment were reviewed. Information on radiation dose, success of the intervention and whether the patient received pulsed, continuous or a combination of both were collected. All procedures were conducted by an interventional radiologist on a GE OEC 9800 mobile fluoroscopy machine. Of the 111 patients who underwent PAE for BPH, a total of 66 patients received only continuous flow fluoroscopy while 45 patients received a combination of continuous and pulse flow. Of the two groups, there was no significant difference in failure rates. Pulse flow and continuous flow fluoroscopy did not show any significant difference. This indicates that patients who undergo prostate artery embolization can receive pulsatile flow without leading to increased procedural failure rates. This is especially relevant for outpatient facilities that often do not typically have fixed fluoroscopy units for performing PAE.

Does Surgical Experience Decrease Radiation Exposure in the Operating Room?

Intraoperative fluoroscopy facilitates minimally invasive surgery, and although it is irreplaceable in terms of intraoperative guidance, it results in substantial radiation exposure to the patient and surgical team. Although the risk of radiation exposure because of equipment factors has been described, there is little known about the impact of surgeon experience on radiation exposure. The aim of this study was to determine whether there is a relationship between years of surgical experience and total dose of radiation used for an archetypal pediatric orthopaedic surgical procedure that requires intraoperative fluoroscopy. This was a retrospective cohort study of children undergoing closed reduction and percutaneous pinning for supracondylar humerus fractures at a level I pediatric trauma center. Information pertaining to radiation dosage was gathered including fluoroscopic time, total images acquired, magnification use, and dose area product (DAP). Regression analysis was used to evaluate the effect of surgeon experience on the outcome variables. A total of 759 pediatric patients treated by 17 attending surgeons were included. The median surgeon experience was 8.94 years (interquartile range, 5.9 to 19.8). Increased number of pins was associated with increased DAP (P<0.001) and lower years of experience (P=0.025). There was significantly higher fluoroscopy time in seconds (56.9 vs. 42.1 s, P=0.001), DAP (179.9 vs. 110.3 mGy-cm2, P=0.001), use of magnification (39.5 vs. 31.9 s, P=0.043), and total number of images obtained (74.5 vs. 57.6, P=0.008) in attending surgeons with <1 year of experience compared with those with greater experience. An operator extremity was visible in at least 1 saved image in 263 of 759 (35%) cases. Increased surgical experience was significantly associated with decreased fluoroscopy usage, including time, number of images, and dose. Surgeon inexperience increases radiation exposure for patients and staff by over 60% when treating supracondylar humerus fractures. This study clearly identifies methods to reduce radiation exposure, including use of pulsed fluoroscopy instead of continuous fluoroscopy, decreasing use of magnification, removing the operator's extremity from the field, and judicious use and placement of each additional pin. Level III.

Evaluation of peak skin dose during percutaneous coronary intervention procedures: relationship with fluoroscopic pulse rate and target vessel.

This study aimed to evaluate the relationship between the peak skin dose (PSD) associated with radiation skin injury and the fluoroscopic pulse rate or target vessel during percutaneous coronary intervention (PCI) procedures. We consecutively included 213 patients who underwent PCI procedures. The fluoroscopic time (FT), total number of cine frames, reference air kerma (RAK), and PSD were compared between the two types of fluoroscopic pulse rates (10 and 7.5 pulses/s) and among target vessels. The total number of X-ray tube angulations for each target vessel was also investigated. The median FT was 21.5min in the 10 pulses/s group and 19.4min in the 7.5 pulses/s group (p = 0.068, Wilcoxon rank sum test). The median PSD in the 10 pulses/s group was 749mGy, which was significantly higher than that in the 7.5 pulses/s group (549mGy) (p < 0.001). The median RAK in the right coronary artery (RCA) was equivalent to that in the left anterior descending artery. However, among the target vessels, the median PSD tended to be the highest in the RCA. There was a difference in the X-ray tube angulation used depending on the target vessel. PCI in the RCA used the left anterior oblique angle more frequently than PCI in the other vessels and tended to use only one angulation. The calculated PSD was related to the target vessel of the PCI procedure, and it was also closely related to the X-ray tube angulation.

Dose Load during Angiographic Procedures RCA Stenting

This article is a continuation of the study of the dose load received by an interventional cardiologist during angiographic procedures and particularly during RCA stenting. To calculate the dose load, dosimetric measurements of the effective dose were carried out while working with a Philips Allura Xper FD10 angiographic system in the invasive department of the Special Hospital for Active Treatment in Cardiology, Varna, Bulgaria. The measurements were carried out for the two operating modes of the angiographic system—radio- graphy and pulse fluoroscopy. In order to obtain a clear assessment of the received dose of the principal cardiologist, the measurements were carried out for three positions of the patient table—zero, lowest and highest position, as well as for three control points: “Head”, “Gonads”, “Feet”. In this procedure following projections are used: LAO-cranial—as first basic projection, RAO- cranial—as second basic and Pure Сranial—as third basic projection. For this reason, calculations have been made for each of these projections. The results convincingly show maximum dose load when radiography is used, although the duration of radiography is significantly shorter than the duration of pulse fluoroscopy. A concluded that the position of the patient table is important during the work of the principal cardiologist and the use of individual radiation protection equipment is not only recommended, but should be mandatory, as indicated in both Bulgarian and international legislation.

Dose Load during Orthopedic Procedures

This article discusses the dose load of people working with a C-arm X-ray system during orthopedic procedures. We measured the effective doses received by the doctor-operator and his assistant at three points of the body—head, gonads and feet, in radiography mode (single shot) and in three sub-modes of the fluoroscopy mode—continuous fluoroscopy; 1/2 dose fluoroscopy and pulse fluoroscopy. Calculations were made for dose rate the resulting our measurements due to the fact that at the different exposure modes are used different exposure times. For a more accurate comparison of the dose load in the different operating modes, we calculated the time for reaching the dose limit for the personnel given in the Bulgarian legislation is calculated—20 mSv per year. The results of all measurements and calculations show that the dose load in the radiography mode (single shot) is several times larger than the dose that was received in the three variations of the fluoroscopy modes. Our main goal by this research is to convincingly show orthopedic surgeons and traumatologists that using a fluoroscopy mode (in all its variations) of the C-arm X-ray system in the position of the tube under the patient table is best for their work, appreciating terms of work, image quality, informational value and dose load of the staff.

Radiation dose during fluoroscopically guided central venous access device insertion: Retrospective observational study

IntroductionCentral venous access devices (CVADs) are used to deliver intravenous therapy to the bloodstream. CVAD insertion is sometimes fluoroscopically guided and thus associated with radiation dose to both the patient and the staff members within the room. The objective of this study is to assess the radiation dose to the patient through a retrospective audit and directly measure the exposure to staff members in simulated procedures. A secondary objective is to evaluate the radiation exposure to the staff and patients when utilising fluoroscopic pulse rate of 7.5pps and 4pps. Material and methodsA retrospective audit of patients undergoing Permcath and Hickman line insertions was conducted. The patients were grouped by the pulse rate used for the duration of the study; 4 pulses per second (pps) (n=24) and 7.5 pps (n=33). A STEP OD-2 monitor and PMMA was used in a simulated environment to estimate the radiation exposure to locations that a Radiologist, Nurse and Radiographer would be standing during the procedures using the average procedure details collected in the retrospective audit. Measurements were conducted at heights to reflect a whole body estimate and an estimate to the lens of the eye. ResultsThe results show that the median dose area product (DAP) for CVAD insertion is 0.7Gycm2 and 0.3Gycm2 for procedures done at 7.5pps and 4pps, respectively. This corresponded to an effective dose of 0.22mSv and 0.1mSv. The radiologist, nurse and radiographer were exposed to a whole-body shielded dose of 0.36μSv, 0.1μSv and 0.05μSv when 7.5pps was utilised and 0.13μSv, 0.03μSv and 0.02μSv when 4pps was used. The exposure to the head of radiologist, nurse and radiographer was 2.1μSv, 1.4μSv, and 0.6μSv in the 7.5pps studies and 0.7μSv, 0.5μSv, and 0.2μSv when 4pps was used. ConclusionThe patient effective dose was estimated to be 0.1–0.22mSv depending on the fluoroscopic pulse rate utilised during CVAD insertions. Additionally, The radiologist, nurse and radiographer whole body and lens exposure was estimated in a simulated setting. In all cases, there was a statistically significant dose reduction when the lower fluoroscopic pulse rate was used. Thus, where possible, consideration should be given to utilising a lower pulse rate during CVAD insertions to reduce the exposure to both staff and patients.

Comparison of dose rate when working with a C-arm X-ray system

Introduction: During working with sources of ionizing radiation, it is of special importance to take into account the dose load of the personnel working with such equipment. Aim: The aim of this article is to discuss the dose load of people working with mobile X-ray systems with a C-arm, who perform orthopedic procedures in the Clinic of Orthopedics and Traumatology of the St. Marina University Hospital, Varna. This research tries to convincingly show orthopedic surgeons and traumatologists that using a fluoroscopy mode (in all its variations) of the C-arm X-ray system when the tube is positioned under the patient table is best for their work when it comes to the working conditions, the image quality, the information value and the dose exposure of the staff. Materials and Methods: In the article a comparison of the dose load (effective dose) was made based on dosimetric measurements with respect to the personnel in different modes of operation of the X-ray equipment—roentgenoscopy (single shot) and fluoroscopy. The doses received by the surgeon-operator and his assistant were measured at three points of the body—head, gonads and feet, in radiography mode (single shot) and in three sub-modes of the fluoroscopy mode—continuous fluoroscopy, ½ dose fluoroscopy, and pulse fluoroscopy. For a more accurate comparison of the dose load in the respective operating modes, the time for reaching the dose limit for the personnel, determined by the Bulgarian legislation, was calculated—namely 20mSv per year. Results: The results of all measurements and calculations showed that the dose load in the radiography mode (single shot) was several times larger than the dose that was received in the three variations of the fluoroscopy mode at the same operating time. Conclusion: The results suggest that when using the fluoroscopy mode, even in the sub-mode with the highest dose load, it gives a lower dose than using the mode roentgenography, at the same time of operation of the X-ray tube.

Radiation exposure of patients during endourological procedures: IAEA-SEGUR study

Fluoroscopy is increasingly used to guide minimally invasive endourological procedures and optimised protocols are needed to minimise radiation exposure while achieving best treatment results. This multi-center study of radiation exposure of patients was conducted by the South-Eastern European Group for Urolithiasis Research (SEGUR), in cooperation with the International Atomic Energy Agency. Seven clinical centers from the SEGUR group collected data for 325 procedures performed within a three-months period, including standard percutaneous nephrolithotomy (PCNL), mini PCNL, retrograde intrarenal surgery (RIRS), semirigid ureterorenoscopy (URS) and flexible URS. Data included: air kerma area product (P KA), air kerma at the patient entrance reference point (K a,r), fluoroscopy time (FT), number of radiographic images (N) and fluoroscopy pulse rate, as well as total procedure duration, size and location of stones. Data were centrally analysed and statistically compared. Median P KA values per center varied 2-fold for RIRS (0.80–1.79 Gy cm2), 7.1 fold for mini-PCNL (1.39–9.90 Gy cm2), 7.3 fold for PCNL (2.40–17.50 Gy cm2), 19 fold (0.13–2.51 Gy cm2) for semi-rigid URS and 29-fold for flexible URS (0.10–2.90 Gy cm2). Lower P KA and K a,r were associated with use of lower FT, N and lower fluoroscopy pulse rate. FT varied from 0.1 to 14 min, a small fraction of the total procedure time, ranging from 10 to 225 min. Higher N was associated with higher P KA and K a,r. Higher median P KA in PCNL was associated with the use of supine compared to prone position. No correlation was found between the concrement size and procedure duration, FT, P KA or K a,r. Dose values for RIRS were significantly lower compared to PCNL. The maximum K a,r value of 377 mGy was under the threshold for radiation induced skin erythema. The study demonstrated a potential for patient dose reduction by lowering FT and N, using pulsed fluoroscopy and beam collimation.

Low fluoroscopy pulse rates as a mean to reduce radiation exposure during neuroendovascular procedure

Low fluoroscopy pulse rates as a mean to reduce radiation exposure during neuroendovascular procedure

S0926 The Impact of Replacing Old C-Arms on Radiation Exposure

INTRODUCTION: Fluoroscopy guidance is widely employed in the field of gastroenterology, particularly by advanced endoscopists for ERCP. This comes with the risk of ionizing radiation. Ionization can cause DNA damage and cell death, leading to cancer and genetic defects. The longer the radiation exposure and the higher the radiation levels, the more likely one is to experience these consequences. Thus, the Nuclear Regulatory Commission (NRC) set an occupational dose limit of 50 Millisievert (mSv) effective dose per year. This study investigates the effect that updating our C-Arm will have on radiation exposure by comparing ionizing radiation effects of the OEC 9900 Elite to the newer OEC Elite. METHODS: We replicated the room positioning of a typical ERCP with a C-Arm adjacent to our bed and a stack of acrylic plates to simulate patient tissue. We measured energy output and levels of radiation in the air at bedside, 33” from the center of the bed (position of endoscopist), and at the head of the table, 46” from the center of the bed (position of anesthetist). The same set-up and measurements were completed with the OEC 9900 Elite and the OEC Elite. For each system and position we calculated mSv/hr with continuous and pulsed fluoroscopy. RESULTS: At each position, the OEC Elite emitted less energy and ionizing radiation or potential for radiation-induced harm than the OEC 9900 Elite. Continuous imaging with OEC 9900 Elite emitted 0.12 mSv/hr at the head of the bed and 0.49 mSv/hr at the bedside, while the OEC Elite emitted 0.04 mSv/hr and 0.14 mSv/hr, respectively. CONCLUSION: This study confirms that the greater the distance a staff member stands from the location that x-rays enter the patient, the lower their radiation exposure will be. Similarly, pulsed imaging mode lowers scatter radiation exposure. Unique to this study, is the demonstration that the OEC Elite operated at a lower energy output (kVp and mA), which resulted in lower scatter radiation exposure. With an average of 8 minutes of fluoroscopy time per ERCP and approximately 850 ERCP cases done annually in our endoscopy center, the annual effective dose is strongly influenced by C-Arm choice. Continuous fluoroscopy imaging with OEC 9900 Elite produces 13.92 mSv/year at the head of the bed and 55.60 mSv/year at the bedside. However, the OEC Elite produces 4.18 mSv/year and 15.41 mSv/year at respective locations and would allow an endoscopist standing at bedside for these cases to remain within NRC occupational dose limit of 50 mSv annually.Table 1.: Depicts the energy output in kVp and mA as well as the measurement of radiation in a volume of air (mR/hr) for each device, image mode, and location. kVp = Kilovoltage peak; mA = Milliamperage; mR/hr = Milliroentgen per hourTable 2.: Depicts stochastic biological risk of ionizing radiation in rates of Millisievert, which is the commonly used SI (International System of Units) measurement. Shown above in rates per hour, case, and year. In this study, a case represents 8 minutes of fluoroscopy time, which is the average per ERCP. A year consists of 850 ERCP cases, which is the approximate ERCP case load in our Endoscopy Center at UMMCImage 1.: Demonstrates the experimental set-up used to simulate an endoscopic case with fluoroscopic guidance. Here, a Fluke 451 Ion Chamber Survey Meter is used to measure ionizing radiation from bedside at typical position of endoscopist.

Radiation Exposure of Surgical Team During Endourological Procedures: International Atomic Energy Agency-South-Eastern European Group for Urolithiasis Research Study.

Introduction: Fluoroscopy-guided endourology procedures require proper radiation protection to minimize radiation risk. This multicenter study aimed at investigating radiation protection practice and related radiation exposure of operating team members. Materials and Methods: Six endourology centers from the South-Eastern European Group for Urolithiasis Research answered questionnaires and collected data of 315 procedures performed within a 3-months period, with simultaneous measurement of dose to staff and dose area product (DAP) to patient. A pair of calibrated personal dosimeters, one for body and one for eye-lens dose, was worn by all key staff members. Dosimeters were centrally calibrated, measured, and analyzed. Results: The annual workload ranged from 173 to 865 procedures per center. Practice of personal dose monitoring and use of radiation protection shielding was found to be inconsistent. Lead aprons and thyroid collars were used by all, whereas protective eyewear was used in only half of centers. Due to the regular use of protective aprons, the whole-body dose of all 44 monitored staff members was safely below the regulatory dose limits. Eye-lens dose of 17 (14 urologists and 3 assisting staff) was above the dosimeter detection level, and dose per procedure varied from <10 to 63 μSv. The highest annual eye-lens dose of 13.5 mSv was found for the surgeon in the busiest department by using an over-the-couch X-ray tube without a ceiling suspended screen. Working closer to patient body with no protection resulted in a six-time higher eye-lens dose per DAP for a surgeon compared with others in the same center. Lower eye-dose per procedure was associated with lower DAP to patient and with the use of an under-the-couch tube, lower fluoroscopy pulse rate, collimation, fluoroscopy time, and acquired images. Conclusions: The study results call for the need to establish standard protocols about use of fluoroscopy during endourology procedures and to increase radiation protection knowledge and awareness of surgical staff.

Evaluation of intrathoracic tracheal narrowing in patients with obstructive ventilatory impairment using dynamic chest radiography: A preliminary study

PurposeDynamic chest radiography (DCR) can observe the dynamic structure of the chest using continuous pulse fluoroscopy irradiation. However, its usefulness remains largely undetermined. The purpose of this study was to examine the relationship between changes in tracheal diameter during deep breathing and obstructive ventilation disorders using DCR. MethodTwelve participants with obstructive ventilatory impairment and 28 with normal pulmonary function underwent DCR during one cycle of deep inspiration and expiration. Three evaluators blinded to pulmonary function test results independently measured lateral diameters of the trachea in DCR images to determine whether there was a difference in the amount of change in tracheal diameter depending on the presence or absence of pulmonary dysfunction. Tracheal narrowing was defined as a decrease in the lateral tracheal diameter of more than 30 %. Participants were divided into a narrowing group and a non-narrowing group, and it was examined whether each group correlated with values of pulmonary function tests. ResultsTracheal diameter was significantly narrowed in subjects with obstructive ventilatory impairment compared to normal subjects (P < 0.01). When subjects were divided into narrowing (tracheal narrowing rate [TNr] = 41.5 ± 7.7 %, n = 9) and non-narrowing groups (TNr = 9.1 ± 7.0 %, n = 31, p < 0.01), FEV1%-G, and %V25 were significantly smaller in the narrowing group than in the non-narrowing group (p < 0.01). ConclusionsChanges in tracheal diameter during deep breathing were easily evaluated using DCR. DCR may, therefore, be useful for evaluating obstructive ventilation disorders.

Dosis de radiación durante la inserción guiada por fluoroscopia de un dispositivo de acceso venoso central: un estudio observacional retrospectivo

IntroductionCentral venous access devices (CVAD) are used to deliver intravenous therapy to the bloodstream. CVAD insertion is sometimes fluoroscopically guided and thus associated with radiation dose to both the patient and the staff members within the room. The objective of this study is to assess the radiation dose to the patient through a retrospective audit and directly measure the exposure to staff members in simulated procedures. A secondary objective is to evaluate the radiation exposure to the staff and patients when utilising fluoroscopic pulse rate of 7.5 pps and 4 pps. Material and MethodsA retrospective audit of patients undergoing Permcath and Hickman line insertions was conducted. The patients were grouped by the pulse rate used for the duration of the study; 4 pulses per second (pps) (n=24) and 7.5 pps (n=33). A STEP OD-2 monitor and PMMA was used in a simulated environment to estimate the radiation exposure to locations that a Radiologist, Nurse and Radiographer would be standing during the procedures using the average procedure details collected in the retrospective audit. Measurements were conducted at heights to reflect a whole body estimate and an estimate to the lens of the eye. ResultsThe results show that the median dose area product (DAP) for CVAD insertion is 0.7Gy.cm2 and 0.3Gy.cm2 for procedures done at 7.5 pps and 4 pps, respectively. This corresponded to an effective dose of 0.22 mSv and 0.1 mSv. The radiologist, nurse and radiographer were exposed to a whole-body shielded dose of 0.36μSv, 0.1μSv and 0.05μSv when 7.5 pps was utilised and 0.13μSv, 0.03μSv and 0.02μSv when 4 pps was used. The exposure to the head of radiologist, nurse and radiographer was 2.1μSv, 1.4μSv, and 0.6μSv in the 7.5 pps studies and 0.7μSv, 0.5μSv, and 0.2μSv when 4pps was used. ConclusionThe patient effective dose was estimated to be 0.1-0.22 mSv depending on the fluoroscopic pulse rate utilised during CVAD insertions. Additionally, The radiologist, nurse and radiographer whole body and lens exposure was estimated in a simulated setting. In all cases, there was a statistically significant dose reduction when the lower fluoroscopic pulse rate was used. Thus, where possible, consideration should be given to utilising a lower pulse rate during CVAD insertions to reduce the exposure to both staff and patients.

Decreased radiation exposure using pulsed fluoroscopy and a detachable pedicle marker and probe to place pedicle screws: a comparison to current fluoroscopy techniques and CT navigation

Study designQuality improvement evaluation with retrospective analysis.ObjectivesTo compare a technique to place pedicle screws (PS) using a novel detachable pedicle marker and probe (DPMP) and pulsed fluoroscopy (PF) vs. conventional technique utilizing PF with standard instruments (SI) and O-arm.Summary of background dataSpinal fusion with pedicle screw instrumentation (PSI) is the mainstay in treatment of spinal deformities. Reports suggest that CT navigated (O-arm) PS placement is more accurate than fluoroscopy. However, these studies have not considered the increased radiation exposure associated with CT.MethodsThirty-six patients with spinal deformity had PSI using PF and DPMPs. Accuracy of PS placement and radiation data from 14 dosimeters placed on the patient and around the operating room was analyzed. Results were compared to published data.ResultsMean fluoroscopic time was 13.4 s (range 6.0–32.4), and the mean cumulative dose was 3.1 mGy (range 0.2–16.4). Median estimated effective dose to the patient was 0.22 mSv (range 0.0–0.7). The effective dose of radiation was reduced by 80% (0.22 mSv vs. 1.11 mSv) compared to low-dose O-arm. The surgical team did not receive any detectable radiation. The seconds of PF used to assist and confirm placement of PSs was reduced to 1.2 s/level compared to previous reports of 4.49 s/level using SIs. DPMPs reduced fluoroscopy to 0.84 s/PS compared to 7.36 s/PS using SIs to assist and confirm PS placement. PSs were accurately placed in 561 of 576 (97.4%), which is comparable to O-arm and fluoroscopy with SIs.ConclusionsPS placement using PF and DPMPs to assist and confirm PS placement lowers radiation exposure to the patient and surgical team without compromising accuracy compared to O-arm and fluoroscopy with SIs.Level of evidenceTherapeutic, Level IV (Retrospective case series, historical control).

Establishing local diagnostic reference levels for pediatric percutaneous transhepatic cholangiography interventions and optimizing the routine practice.

Liver-transplanted, immunosuppressed pediatric patients undergoing repeated percutaneous transhepatic cholangiography (PTC) require optimized exposure to ionizing radiation. To establish local diagnostic reference levels (DRL) for pediatric PTC and investigate the routine use of X-ray equipment. The study retrospectively analyzed data collected between October 2016 and June 2018 from a single center performing PTC. We collected exposure parameters including kerma area product (PKA), air kerma at patient entrance reference point (Ka,r) and fluoroscopy time via a dose archiving and communication system. Local diagnostic reference levels were derived as the 50th percentile of the distributions while considering published recommended weight groups. We investigated exposure variability with procedure complexity and with technical parameters recovered from the radiation dose structured report. The analysis included 162 PTC procedures performed in 64 children: 58% male, average age 6years (range 39days to 16years) and weight 24kg (range 3-60kg). Local DRLs for weight groups 0-5kg, 5-15kg, 15-30kg, 30-50kg and 50-80kg were, respectively, 6cGy.cm2, 22cGy.cm2, 68cGy.cm2, 107cGy.cm2 and 179cGy.cm2 in PKA. Local DRLs per weight group were also established for intermediate and complex procedures. Radiation dose structured report analysis highlighted good local practice with efficient collimation, low fluoroscopy pulse rate, no magnification and limited use of radiographic acquisitions. Meanwhile, table and detector positioning and tube projection could still be optimized. PKA correlated significantly with the number of acquisitions and tube-to-table distance. We established local DRLs for children undergoing PTC.

SPOT REGION OF INTEREST IMAGING: A NOVEL FUNCTIONALITY AIMED AT X-RAY DOSE REDUCTION IN NEUROINTERVENTIONAL PROCEDURES

Aim of the study: The aim of this study was to describe a new functionality aimed at X-ray dose reduction, referred to as spot region of interest (Spot ROI) and to compare it with existing dose-saving functionalities, spot fluoroscopy (Spot F), and conventional collimation (CC). Material and methods: Dose area product, air kerma, and peak skin dose were measured for Spot ROI, Spot F, and CC in three different fields of view (FOVs) 20 × 20 cm, 15 × 15 cm, and 11 × 11 cm using an anthropomorphic head phantom RS-230T. The exposure sequence was 5 min of pulsed fluoroscopy (7.5 pulses per s) followed by 7× digital subtraction angiography (DSA) runs with 30 frames per DSA acquisition (3 fps × 10 s). The collimation in Spot F and CC was adjusted such that the size of the anatomical area exposed was as large as the Spot ROI area in each FOV. Results: The results for all FOVs were the following: for the fluoroscopy, all measured parameters for Spot ROI and Spot F were lower than corresponding values for CC. For DSA and DSA plus fluoroscopy, all measured parameters for Spot ROI were lower than corresponding parameters for Spot F and CC. Conclusion: Spot ROI is a promising dose-saving technology that can be applied in fluoroscopy and acquisition. The biggest benefit of Spot ROI is its ability to keep the entire FOV information always visible.