National reference doses for common radiographic, fluoroscopic and dental X-ray examinations in the UK

DOSIMETRY OF ADULT AND PEDIATRIC PATIENTS FOR COMMON DIGITAL RADIOGRAPHY EXAMINATIONS

The present work reports dosimetry data on adult and pediatric patients for some common radiographic examinations during the standard hospital routine. The measurements are the part of quality assurance program to determine radiation exposures to patients in these examinations. The entrance skin doses (ESDs) of the patients were measured from 2451 projection for 12 diagnostic examinations in digital radiography (DR). The ESDs in adult patient were measured using thermoluminescence dosemeters placed on the skin of the patient. In pediatric patients, ESDs were evaluated from the measured air kerma with ionization chamber, patient specific parameters and known values of machine exposure factors during examinations. The third quartile values of ESDs are proposed as local diagnostic reference levels (LDRLs) for radiographic examinations having statistical significant number of exposures (n ≥ 20). The proposed LDRL values are also compared with earlier published LDRL/DRL values.

Comparison of incident air kerma (ki) of common digital and analog radiology procedures in Kohgiluyeh and Boyer-Ahmad province

Introduction: Although in many developed countries, Analog radiography (AR) is replaced with digital radiography (DR) but AR is still widely used in many countries included Iran. Therefore, dosimetrically assessment of delivered dose is very important to avoid unnecessary patient dose.

Materials and Methods: In this study, all imaging centers in Kohgiluyeh and Boyer-Ahmad were selected. The initial information included the mean kVp and mAs used by the personnel to perform each radiological procedure were gathered through a questionnaire. Barracuda dosimeter was then used to measure Incident air kerma (ki). Data obtained from digital radiography (DR) and analogue radiography (AR) were then analyzed and compared to each other.

Results: The mean incident air kerma (ki) for five radiological procedures (chest AP&Lat, Skull AP&Lat, Lumbar spine AP&Lat, Thoracic spine AP&Lat and Pelvis) in digital devices were 0.38&1.34, 2.1&1.94, 4.99&7.83, 4.18& 6.41 and 4.33 mGy and those for analogue devices were 0.7&1.28, 3.05&3.02, 7.25&9.9, 7.125&8.36 and 5.36 mGy, respectively.

Discussion and Conclusion: The use of low kVp or high mAs is one of the reasons to increase the incident air kerma (ki) in analogue methods comparing to digital methods in all procedures except the chest (in Lateral view). Also the results, surprisingly, showed that in some of the analogue methods incident air kerma (ki) was less than digital methods which is most probably because of the auto-exposure conditions.

Radiation dose metrics in multidetector computed tomography examinations: A multicentre retrospective study from seven tertiary care hospitals in Kerala, South India

BACKGROUND

Presently, computed tomography (CT) is the most important source of medical radiation exposure. CT radiation doses vary considerably across institutions depending on the protocol and make of equipment. India does not yet have national or region-specific CT diagnostic reference levels.

AIM

To evaluate radiation doses of consecutive multidetector CT (MDCT) examinations based on anatomic region, performed in 1 month, collected simultaneously from seven tertiary care hospitals in Kerala.

SETTINGS AND DESIGN

Descriptive study.

MATERIALS AND METHODS

We collected the CT radiation dose data of examinations from the seven collaborating tertiary care hospitals in Kerala, performed with MDCT scanners of five different makes. The data included anatomic region, number of phases, CT dose index (CTDIvol), dose-length product (DLP), and effective dose (ED) of each examinations and patient demographic data.

STATISTICAL ANALYSIS

We calculated the 25th, 50th, and 75th percentiles of the CTDIvol, DLP, and ED according to anatomic region. We made descriptive comparisons of these results with corresponding data from other countries.

RESULTS

Of 3553 patients, head was the most frequently performed examination (60%), followed by abdomen (19%). For single-phase head examinations, 75th percentile of CTDIvol was 68.1 mGy, DLP 1120 mGy-cm, and ED 2.1 mSv. The 75th percentiles of CTDIvol, DLP, and ED for single-phase abdomen examinations were 10.6, 509.3, and 7.7, and multiphase examinations were 14.6, 2666.9, and 40.8; single-phase chest examinations were 23.4, 916.7, and 13.38, and multiphase examinations were 19.9, 1737.6, and 25.36; single-phase neck were 24.9, 733.6, and 3.814, and multiphase neck were 24.9, 2076, and 10.79, respectively.

CONCLUSION

This summary CT radiation dose data of most frequently performed anatomical regions could provide a starting point for institutional analysis of CT radiation doses, which in turn leads to meaningful optimization of CT.

Patient radiation doses in intraoral and panoramic X-ray examinations in Sudan

Radiation doses were measured for the first time in intraoral and panoramic dental radiology at Sudanese hospitals. Doses were determined using various exposure settings for adults and children in 8 intraoral and 6 panoramic X-ray devices. The study sample was equally divided between devices using a digital image receptor (DR) and those using conventional screen film (SF). Radiation doses are reported in terms of incident air kerma (IAK) (intraoral radiology) and kerma area product (P_KA) (panoramic radiology). IAK values in intraoral radiology were: 1.45 mGy (DR), 4.45 mGy (SF), and 3.01 mGy (combined). For panoramic radiology, P_KA values ranged: from 35.8 to 103.2 mGy cm² (average: 70.4 mGy cm²) for children and from 65.7 to 151.4 mGy cm² (average: 103.4 mGy cm²) for adults. The results showed that the downward trend in patient doses can be achieved using digital imaging. The study revealed important concerns surrounding radiation protection, such as the lack of regular quality assurance programs and the use of circular collimators.

Radiation Exposure in the Medical ICU: Predictors and Characteristics

BACKGROUND

Patients admitted to the medical ICU (MICU) are often subjected to multiple radiologic studies. We hypothesized that some endure radiation dose exposure (cumulative effective dose [CED]) in excess of annual US federal occupational health standard limits (CED ≥ 50 mSv) and 5-year cumulative limit (CED ≥ 100 mSv). We also evaluated the correlation of CED with Acute Physiology and Chronic Health Evaluation (APACHE) III score and other clinical variables.

METHODS

Retrospective observational study conducted in an academic medical center involving all adult admissions (N = 4,155) to the MICU between January 2013 and December 2013. Radiation doses from ionizing radiologic studies were calculated from reference values to determine the CED.

RESULTS

Three percent of admissions (n = 131) accrued CED ≥ 50 mSv (1% [n = 47] accrued CED ≥ 100 mSv). The median CED was 0.72 mSv (interquartile range, 0.02-5.23 mSv), with a range of 0.00 to 323 mSv. Higher APACHE III scores (P = .003), longer length of MICU stay (P < .0001), sepsis (P = .03), and gastrointestinal disorders and bleeding (P < .0001) predicted higher CED in a multivariable linear regression model. Patients with gastrointestinal bleeding and disorders had an odds ratio of 21.05 (95% CI, 13.54-32.72; P < .0001) and 6.94 (95% CI, 3.88-12.38; P < .0001), respectively, of accruing CED ≥ 50 mSv in a multivariable logistic regression model. CT scan and interventional radiology accounted for 49% and 38% of the total CED, respectively.

CONCLUSIONS

Patients in the MICU are exposed to radiation doses that can be substantial, exceeding federal annual occupational limits, and in a select subset, are > 100 mSv. Efforts to justify, restrict, and optimize the use of radiologic resources when feasible are warranted.

PATIENT EXPOSURE DURING PLAIN RADIOGRAPHY AND MAMMOGRAPHY IN JAPAN IN 1974-2014

We investigated changes in the entrance skin dose (ESD) and the mean glandular dose (MGD) during plain radiography or mammography in Japan from 1974 to 2014. Surveys regarding the conditions used for plain radiography and mammography were performed throughout Japan in 1974, 1979, 1989, 1993, 1997, 2001, 2003, 2007, 2011 and 2014. The anatomical regions considered were categorised as follows: skull anteroposterior (AP), lumbar AP, lumbar lateral (LAT), pelvis (AP), ankle, chest posteroanterior (PA), Guthmann (lateral pelviography for pregnant women), infant hip joint and mammography. The doses for all anatomical regions decreased from 1974 to 1993. The MGD for mammography remained low from 1993 to 2014, and the ESDs for chest (PA) radiography trended upward. After the 2000s, the use of digital imaging increased in Japan. This is the first long-term study to examine changes in ESDs and MGDs in Japan.

Time-Course Reduction in Patient Exposure to Radiation From Coronary Interventional Procedures

Background—

The frequency of complex percutaneous coronary interventions (PCIs) has increased in the last few years, with a growing concern on the radiation dose received by the patients. Multicenter data from large unselected populations on patients’ radiation doses during coronary angiography (CA) and PCI and temporal trends are lacking. This study sought to evaluate the temporal trends in patients’ exposure to radiation from CA and PCI.

Methods and Results—

Data were taken from the CARDIO-ARSIF registry that prospectively collects data on all CAs and PCIs performed in the 36 catheterization laboratories in the Greater Paris Area, the most populated regions in France with about 12 million inhabitants. Kerma area product and Fluoroscopy time from 152 684 consecutive CAs and 103 177 PCIs performed between 2009 and 2013 were analyzed. A continuous trend for a decrease in median [interquartile range] Kerma area product was observed, from 33 [19–55] Gy cm 2 in 2009 to 27 [16–44] Gy cm 2 in 2013 for CA ( P <0.0001), and from 73 [41–125] to 55 [31–91] Gy cm 2 for PCI ( P <0.0001). Time-course differences in Kerma area product remained highly significant after adjustment on Fluoroscopy time, PCI procedure complexity, change of x-ray equipment, and other patient- and procedure-related covariates.

Conclusions—

In a large patient population, a steady temporal decrease in patient radiation exposure during CA and PCI was noted between 2009 and 2013. Kerma area product reduction was consistent in all types of procedure and was independent of patient-related factors and PCI procedure complexity.

Estimation of effective dose and radiation risk in pediatric barium studies procedures

The objectives of this study are to assess pediatric radiation exposure in certain barium studies and to quantify the organ and effective doses and radiation risk resultant from patients' irradiation. A total of 69 pediatric barium studies for upper and lower gastrointestinal tract. Patients' radiation dose was quantified in terms of Entrance surface air kerma (ESAKs) using exposure parameters and DosCal software. Organ and effective doses (E) were extrapolated using national Radiological Protection Board software (NRPB-R279). The mean ± (SD) and the range of patient doses per procedure were 3.7 ± 0.4 (1.0-13.0)mGy, 7.4 ± 1.7(5.5-8.0)mGy and 1.4 ± 0.9 (0.5-3.6)mGy for barium meal, swallow and enema, respectively. The mean effective doses were 0.3 ± 0.03 (0.08-1.1)mSv, 0.2 ± 1.6 (0.44-0.7)mSv and 0.3 ± 0.9 (0.1-0.8)mSv at the same order. The radiation dose were higher compared to previous studies. Therefore, pediatrics are exposed to avoidable radiation exposure. Certain optimization measures are recommended along with establishing national diagnostic reference level (DRL) to reduce the radiation risk.

Radiation Doses to Patients in Interventional Coronary Procedures-Estimation of Updated National Reference Levels by Dose Audit

The objective of this study was to estimate the French national updated reference levels (RLs) for coronary angiography (CA) and percutaneous coronary intervention (PCI) by a dose audit from a large data set of unselected procedures and in standard-sized patients. Kerma-area product (PKA), air kerma at interventional point (Ka,r), fluoroscopy time (FT), and the number of registered frames (NFs) and runs (NRs) were collected from 51 229 CAs and 42 222 PCIs performed over a 12-month period at 61 French hospitals. RLs estimated by the 75th percentile in CAs and PCIs performed in unselected patients were 36 and 78 Gy.cm² for PKA, 498 and 1285 mGy for Ka,r, 6 and 15 min for FT, and 566 and 960 for NF, respectively. These values were consistent with the RLs calculated in standard-sized patients. The large difference in dose between sexes leads us to propose specific RLs in males and females. The results suggest a trend for a time-course reduction in RLs for interventional coronary procedures.

Initial Investigation of Factors Influencing Radiation Dose to Patients Undergoing Barium-Based Fluoroscopy Procedures in Tanzania

The aim of this study was to investigate the nature and causes of radiation dose imparted to patients undergoing barium-based X-ray fluoroscopy procedures in Tanzania and to compare these doses to those reported in the literature from other regions worldwide. The air kerma area product (KAP) to patient undergoing barium investigations of gastrointestinal tract system was obtained from four consultant hospitals. The KAP was determined using a flat transparent transmission ionization chamber. Mean values of KAP for barium swallow (BS), barium meal (BM) and barium enema (BE) were 2.79, 2.62 and 15.04 Gy cm2, respectively. The mean values of KAP per hospital for the BS, BM and BE procedures varied by factors of up to 7.3, 1.6 and 2.0, respectively. The overall difference between individual patient doses across the four consultant hospitals investigated differed by factors of up to 53, 29.5 and 12 for the BS, BM and BE procedures, respectively. The majority of the mean values of KAP was lower than the reported values for Ghana, Greece, Spain and the UK, while slightly higher than those reported for India. The observed wide variation of KAP values for the same fluoroscopy procedure within and among the hospitals was largely attributed to the dynamic nature of the procedures, the patient characteristics, the skills and experience of personnel, and the different examination protocols employed among hospitals. The observed great variations of procedural protocols and patient doses within and across the hospitals call for the need to standardize examination protocols and optimize barium-based fluoroscopy procedures.

THE ESTABLISHMENT OF LOCAL DIAGNOSTIC REFERENCE LEVELS IN ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY: A PRACTICAL TOOL FOR THE OPTIMISATION AND FOR QUALITY ASSURANCE MANAGEMENT

Fluoroscopic procedures are an area of special concern in relation to radiation protection. The aim of this study was to describe the current level of patient radiation doses in endoscopic retrograde cholangiopancreatography (ERCP) collected from a single centre, as well as to establish and review local diagnostic reference levels (DRLs) in ERCP. A total of 100 patients' radiation doses in ERCP were recorded, and the third-quartile method was adopted to establish local DRLs for ERCP. The mean dose area product (DAP) was 2.05 Gy cm2, fluoroscopy time (FT) 1.7 min and the number of images was 3. The proposed local DRLs for ERCP were 3.00 Gy cm2 and 3.0 min. Local DRLs were reviewed in a sample of 25 patients 5 y after they had been established. In reviewing data, the averages of DAP and FT were below the local DRLs. Local DRLs help in the optimisation process of fluoroscopic procedures and guides to a good clinical practice.

Quantification of radiation exposure in the operating theatre during management of common fractures of the upper extremity in children

Introduction Surgical procedures to manage trauma to the wrist, forearm and elbow in children are very common. Image intensifiers are used routinely, yet studies/guidelines that quantify expected radiation exposure in such procedures are lacking. Methods Information on demographics, injury type, surgeon grade and dose area product (DAP) of radiation exposure per procedure was collected prospectively for 248 patients undergoing manipulation/fixation of injuries to the elbow, forearm or wrist at a paediatric hospital over 1 year. Results DAP exposure (in cGycm(2)) differed significantly across different procedures (p<0.001): wrist manipulation under anaesthesia (MUA; median, 0.39), wrist k-wiring (1.01), forearm MUA (0.50), flexible nailing of the forearm (2.67), supracondylar fracture MUA and k-wiring (2.23) and open reduction and internal fixation of the lateral humeral condyle (0.96). Fixation of a Gartland grade-3 supracondylar fracture (2.94cGycm(2)) was associated with higher exposure than grade-2 fixation (1.95cGycm(2)) (p=0.048). Fractures of the wrist or forearm necessitating metalwork fixation resulted in higher exposure than those requiring manipulation only (both p<0.001). For procedures undertaken by trainees, trainee seniority (between year-5 and year-8 and clinical fellow, p≥0.24) did not affect the DAP significantly. Conclusions The spectrum of radiation exposures for common procedures utilised in the management of paediatric upper limb trauma were quantified. These findings will be useful to surgeons auditing their practice and quantifying radiation-associated risks to patients. Our data may serve as a basis for implementing protocols designed to improve patient safety.

DOSE REFERENCE LEVELS IN SPANISH INTRAORAL DENTAL RADIOLOGY: STABILISATION OF THE INCORPORATION OF DIGITAL SYSTEMS IN DENTAL CLINICAL PRACTICES

A total of 34 044 official quality assurance reports in dental radiodiagnostic surgery from 16 regions of Spain, compiled from 2002 to 2014, were studied in order to determine the progress of diagnostic reference levels (DRLs) for obtaining diagnostic images under normal conditions for clinical practice in Spanish dental clinics. A DRL of 2.8 mGy was set in 2014, which represents a 41.7 % decrease compared with that of 2002 (4.8 mGy). Over the same time period, the mean dose fell by 55.2 %. However, over the last 3 y, the stabilisation of the mean dose administered to patients has been observed with only a 6.7 % reduction in DRLs, which corresponds to the stabilisation of dental radiodiagnostic surgery on replacing the use of radiographic film with digital imaging systems.

Knowledge and Attitude among General Dental Practitioners towards Minimally Invasive Dentistry in Riyadh and AlKharj

INTRODUCTION

Minimally Invasive Dentistry (MID) emphasizes conservative caries management strategies resulting in less destruction of tooth structure, a deviation of the traditional GV Black's restorative principles. However, there seems to be either deficiency in knowledge or little intention by general dental practitioners to adopt these principles.

AIM

The aim of this study was to assess the knowledge and attitude among general dental practitioners towards minimally invasive dentistry in Riyadh and AlKharj cities of Saudi Arabia.

MATERIALS AND METHODS

Self-administered structured questionnaires were handed to general dental practitioners (GDPs) in the cities of Riyadh and AlKharj in Saudi Arabia. Several questions, including Likert-type scale response categories (1-5), were used. The questions assessed the respondents' levels of agreement regarding diagnostic, preventive and restorative techniques such as use of caries risk assessment, use of high fluoride tooth paste, Atraumatic Restorative Treatment and tunnel preparations.

RESULTS

Out of 200 respondents, 161 GDPs with overall response rate of 80.5% completed the questionnaires. The GDPs showed significantly different approach with regards to the use of sharp explorer for caries detection (p = 0.014). Almost 60% of the participants had received no special education regarding minimally invasive procedures. Moreover, GDPs who had received MID training showed significantly better knowledge and attitude in adopting minimally invasive techniques for both diagnosis and treatment of dental caries.

CONCLUSION

Although GDPs possess knowledge about the benefits of MID; however, study showed deficiencies in their attitudes towards caries detection methods and application of minimally invasive dentistry procedures.

A dose monitoring system for dental radiography

Purpose

The current study investigates the feasibility of a platform for a nationwide dose monitoring system for dental radiography. The essential elements for an unerring system are also assessed.

Materials and Methods

An intraoral radiographic machine with 14 X-ray generators and five sensors, 45 panoramic radiographic machines, and 23 cone-beam computed tomography (CBCT) models used in Korean dental clinics were surveyed to investigate the type of dose report. A main server for storing the dose data from each radiographic machine was prepared. The dose report transfer pathways from the radiographic machine to the main sever were constructed. An effective dose calculation method was created based on the machine specifications and the exposure parameters of three intraoral radiographic machines, five panoramic radiographic machines, and four CBCTs. A viewing system was developed for both dentists and patients to view the calculated effective dose. Each procedure and the main server were integrated into one system.

Results

The dose data from each type of radiographic machine was successfully transferred to the main server and converted into an effective dose. The effective dose stored in the main server is automatically connected to a viewing program for dentist and patient access.

Conclusion

A patient radiation dose monitoring system is feasible for dental clinics. Future research in cooperation with clinicians, industry, and radiologists is needed to ensure format convertibility for an efficient dose monitoring system to monitor unexpected radiation dose.

CT dose reduction: approaches, strategies and results from a province-wide program in Quebec

Many studies have shown a statistically significant increase of life-time risk of radiation-induced cancer from CT examinations. In this context, in Canada, the Quebec's provincial clinical center of expertise in radiation safety (CECR) has led a province-wide tour of 180 CT installations in order to: (i) evaluate the technical and functional performance of CT scanners, (ii) evaluate and improve radiation safety practices and (iii) initiate, with local teams, a CT dose optimization process. The CT tour consisted of a two day visit of CT installations by a CECR multidisciplinary team of medical physicists, engineers and medical imaging technologists (MITs) carried out in close collaboration with local teams composed of MITs, radiologists, physicists, engineers and managers. The CECR has evaluated 112 CT scanners since 2011. Optimization of CT protocols was performed in all centers visited. The average dose reduction obtained from optimization was [Formula: see text], [Formula: see text] and [Formula: see text] for adult head, thorax and abdomen-pelvis, respectively. The main recommendations often made by the CECR experts were: (1) the implementation of low-dose protocols for the follow-up of pulmonary nodules and for renal calculi, (2) the compliance to the prescribed scan range as defined by local guidelines, (3) the correct positioning of patients and (4) the use of bismuth shielding to reduce the dose to radiosensitive organs. The CECR approach to optimize CT doses to patients is based on the active participation of local stakeholders and takes into account the performance of CT scanners. The clinical requirements as expressed by radiologists remain at the core of the optimization process.

Evaluation of radiation doses in patient and medical staff during endoscopic retrograde cholangiopancreatography procedures

The radiation exposure dose must be optimised because the hazard resulting from an interventional radiology procedure is long term depending on the patient. The aim of this study was to measure the radiation doses received by the patients and medical staff during endoscopic retrograde cholangiopancreatography (ERCP) procedures. Data were collected during 126 ERCP procedures, including the dose-area product (DAP), entrance dose (ED), effective dose (E), fluoroscopy time (T) and number of digital radiographs (F). The medical staff members each wore a personal thermoluminescence dosemeter to monitor exposure during ERCP procedures. The mean DAP, ED, E and T were 47.06 Gy cm(2), 196.06 mGy, 8.93 mSv, 7.65 min and 9.21 images, respectively. The mean dose to the staff was 0.175 mSv and that to the assistant was 0.069 mSv. The dose to the medical staff was minimal when appropriate protective measures were used. The large variation in the patient doses must be further investigated.

Paediatric doses during some common X-ray procedures at selected referral hospitals in Tanzania

The aim of this study was to determine the radiation doses to paediatric patients of different age groups at three large hospitals for optimisation purposes. The entrance surface air kerma (ESAK) values were determined from the measured X-ray output values using calibrated ionisation chamber, TW 233612 and clinical patient parameters. The air kerma-area product (KAP) values were measured using a calibrated Diamentor E2 system. The volume computed tomography dose index (CTDIvol) and dose length product (DLP) values were obtained from the computed tomography (CT) equipment verified by a calibrated CT chamber, Unifors Xi CT. Irrespective of age groups, the results show that the median ESAK values ranged from 62.6 to 248.1 µGy. The median KAP values ranged from 135.6 to 1612 µGy cm(2), while the median DLP values ranged from 119.1 to 600 mGy cm. Analysis of the results indicates that optimisation can be achieved through good practice awareness and patient dose and image quality evaluations.

Paediatric imaging radiation dose awareness and use of referral guidelines amongst radiology practitioners and radiographers

Objectives

The objectives are to investigate radiology practitioners’ and radiographers’ radiation dose awareness and use of referral guidelines for paediatric imaging examinations.

Methods

A prospective cross-sectional survey was conducted amongst radiology practitioners and radiographers working at a primary paediatric referral centre in Malta. Part of the survey asked participants to indicate the typical effective dose (ED) for several commonly performed paediatric imaging examinations, answer five true-false statements about radiation protection principles, and specify their use of referral guidelines for paediatric imaging.

Results

The return of 112 questionnaires provided a response rate of 66.7 %. Overall, imaging practitioners demonstrated poor awareness of radiation doses associated with several paediatric imaging examinations, with only 20 % providing the correct ED estimate for radiation-based examinations. Nearly all participants had undertaken radiation protection training, but the type and duration of training undertaken varied. When asked about the use of referral guidelines for paediatric imaging, 77.3 % claimed that they ‘did not’ or ‘were not sure’ if they made use of them.

Conclusions

Poor awareness of radiation doses associated with paediatric imaging examinations and the non-use of referral guidelines may impede imaging practitioners’ role in the justification and optimisation of paediatric imaging examinations. Education and training activities to address such shortcomings are recommended.

Key Points

• Imaging practitioners demonstrated poor radiation dose awareness for 5 paediatric imaging examinations.

• Most radiology practitioners and radiographers were ‘not sure’ or ‘did not’ use referral guidelines.

• Imaging practitioners generally considered previously undertaken paediatric imaging examinations.

• Some imaging practitioners had not undertaken training in radiation protection for 10 years.

• Training activities to address imaging practitioners’ poor radiation dose awareness are encouraged.

Intraoperative Fluoroscopy for Ventriculoperitoneal Shunt Placement

OBJECTIVE

Catheter malpositioning is one of the most frequent causes of ventriculoperitoneal shunt dysfunction and revision surgery. Most intraoperative tools used to improve the accuracy of catheter insertion are time consuming and expensive or do not display the final position. We evaluate the usefulness of intraoperative fluoroscopy to decrease catheter malpositioning, and define radiological landmarks to identify the correct localization.

METHODS

A total of 104 patients undergoing ventriculoperitoneal shunt placement were analyzed for shunt position, revision surgery and outcome. The results for patients operated on using intraoperative biplanar fluoroscopic assessment of catheter location (X-ray group, n = 57) were compared with a control group operated without intraoperative radiography (control, n = 47). In order to generate a surgical reference map for intraoperative validation of shunt location, different ventricular system landmarks were defined on three-dimensional computed tomography reconstructions of hydrocephalic patients (n = 60) and exported to a two-dimensional layer of the skull.

RESULTS

The use of intraoperative X-ray imaging correlated with a significant increase of optimal catheter positions (X-ray group, n = 45, 79%; control group, n = 23, 49%; P = 0.0018). The sensitivity and positive predictive value for estimating an optimal shunt catheter position on biplanar imaging was 96% (95% confidence interval, 87%-99%). The specificity and negative predictive value were both 92% (95% confidence interval, 78%-98%).

CONCLUSIONS

Intraoperative fluoroscopy is easy to perform and is a reliable method to assess correct catheter positioning. Based on its predictive value, corrections of malpositioned ventricular catheters can be performed during the same procedure. The use of intraoperative fluoroscopy decreases early surgical revisions in ventriculoperitoneal shunt treatment.

Patient and staff dosimetry during radiographic procedures in an intensive care unit

The performance of radiography in the Intensive Care Unit (ICU) may be associated with a certain level of radiation exposure for staff and patients in the unit. Little evidence on exposure levels is available in the literature. However, healthcare professionals in the ICUs at our centre tend to leave the room during radiographic examinations, potentially compromising patient care. The objectives of this study were to quantify dose levels within the ICU and to evaluate the performance of ICU x-ray studies according to patient dose measurements. This study was conducted in the 18-bed ICU of a third-level hospital. The scattering radiation due to mobile x-ray examinations was measured by using four personal thermoluminiscent dosimeters (TLDs). The dose area product (DAP) was measured at each examination using a transmission chamber installed on the diaphragm of the x-ray equipment. Based on the TLD readings and taking account of the error margin, the annual dose to patients and staff was less than 0.6 mSv. The value given by the DAP meter for chest x-rays was 94  ±  17 mGy cm(2); this value is well below the lower limit recommended by different agencies and committees. Exposure levels were found to be extremely low and pose no apparent risk to staff or to those in beds adjacent to the patients undergoing x-ray examinations, which were correctly performed in the unit.

Conventional versus virtual radiographs of the injured pelvis and acetabulum

BACKGROUND

Evaluation of the fractured pelvis or acetabulum requires both standard radiographic evaluation as well as computed tomography (CT) imaging. The standard anterior-posterior (AP), Judet, and inlet and outlet views can now be simulated using data acquired during CT, decreasing patient discomfort, radiation exposure, and cost to the healthcare system. The purpose of this study is to compare the image quality of conventional radiographic views of the traumatized pelvis to virtual radiographs created from pelvic CT scans.

METHODS

Five patients with acetabular fractures and ten patients with pelvic ring injuries were identified using the orthopedic trauma database at our institution. These fractures were evaluated with both conventional radiographs as well as virtual radiographs generated from a CT scan. A web-based survey was created to query overall image quality and visibility of relevant anatomic structures. This survey was then administered to members of the Orthopaedic Trauma Association (OTA).

RESULTS

Ninety-seven surgeons completed the acetabular fracture survey and 87 completed the pelvic fracture survey. Overall image quality was judged to be statistically superior for the virtual as compared to conventional images for acetabular fractures (3.15 vs. 2.98, p = 0.02), as well as pelvic ring injuries (2.21 vs. 1.45, p = 0.0001). Visibility ratings for each anatomic landmark were statistically superior with virtual images as well.

DISCUSSION

Virtual radiographs of pelvic and acetabular fractures offer superior image quality, improved comfort, decreased radiation exposure, and a more cost-effective alternative to conventional radiographs.

Surgical results with the use of Silicated Calcium Phosphate (SiCaP) as bone graft substitute in Posterior Spinal Fusion (PSF) for Adolescent Idiopathic Scoliosis (AIS)

BACKGROUND

The gold standard iliac crest bone graft (ICBG) used to achieve arthrodesis in spinal fusions is not without complications (donor-site morbidity, iliac wing fractures etc.…). Our objectives were to evaluate the role of silicated calcium phosphate (SiCaP), an osteoconductive synthetic bone graft substitute in conjunction with locally harvested autologous bone in achieving arthrodesis following posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) and report clinic-radiological results / adverse events with its use in a prospective single surgeon case series (Level of evidence [LoE] IV) treated by low implant density index (IDI) constructs (i.e., IDI ≤1.5).

METHODS

Thirty-five patients (8♂ & 2727♀) who underwent PSF and followed-up for a minimum of 2 years formed the study cohort. The mean age at surgery was 15 years (range: 11-21y) and pre-op Cobb angle was 60° (range: 40°-90°). SiCaP mixed with locally harvested bone during exposure and instrumentation was laid over instrumented segments. The average SiCaP used per patient was 32mls (range: 10-60mls). Radiographs were assessed for fusion at serial six monthly follow-ups. All clinical adverse events and complications were recorded.

RESULTS

The mean follow-up was 2.94 years (range: 2-4y). The post-op Cobb angle improved to 23° (range: 2°- 55°) and the mean in-patient stay was 7.72 days (range: 5-13d). The mean number of instrumented segments was 9.4 (range: 4-13) and implant density index (IDI) averaged 1.23 (range: 1.15-1.5). Radiographic new bone formation was seen within 3 months in all cases. All patients (except two) were highly satisfied at minimum follow-up of 8 years. There were two complications warranting revision surgery (deep infection, and implant failure without any evidence of pseudarthrosis). There were no SiCaP specific adverse events in any of the 35 patients.

CONCLUSION

SiCaP facilitated early bony consolidation in operated cohort of AIS patients treated by PSF. There were no inflammatory reaction or other adverse effects associated with its use. SiCaP is a safe alternative to autologous iliac crest bone graft with reduced complications, morbidity, faster recovery and similar infection/fusion rates reported in the literature.

Radiography of scoliosis: Comparative dose levels and image quality between a dynamic flat-panel detector and a slot-scanning device (EOS system)

PURPOSE

To compare radiation dose and image quality between a slot-scanning system (SSS) and a dynamic flat-panel detector (DFD) in assessing scoliosis in children.

METHODS

An experimental study was first performed with a phantom to assess the quality of each device. The clinical part included a prospective observational dosimetric and qualitative comparative study with acquisition of whole-spine X-ray: SSS (31 children), DFD (26 children). Institutional review board approval and informed consent were obtained. Dosimetric statistical analysis was performed from dose area product (DAP) and entrance skin dose measured by thermo-luminescent dosimeters localized in the cervical, thoracic and sacral areas. Assessment of the diagnostic quality (phantom and clinical) was realized by independent evaluation by 3 observers, using statistical analysis of quality score and inter-observer reproducibility.

RESULTS

DAP was equivalent with the 2 systems. Entrance skin dose was significantly higher with DFD in thoracic and pelvic regions (P<0.05). Image quality scores of the SSS were significantly better than DFD for a majority of criteria, in both phantom and clinical evaluations.

CONCLUSION

For scoliosis evaluation, the SSS, compared to the DFD system, offers enhanced image quality while reducing the entrance skin dose in the most radiosensitive areas.

Establishment of diagnostic reference levels for dental panoramic radiography in Greece

The purpose of the present study was to present the national diagnostic reference levels (DRL) established for panoramic dental examinations in Greece. The establishment of DRL, as a tool for the optimisation of radiological procedures, is a requirement of national regulations. Measurements performed by the Greek Atomic Energy Commission on 90 panoramic systems have been used for the derivation of DRL values. DRL values have been proposed for exposure settings of different patient types (child, small adult and standard adult), both for film and digital imaging. The DRLs for different patient types are grouped in three categories: children, small adults (corresponding to female) and average adults (corresponding to male). Proposed DRLs for these groups are 2.2, 3.3 and 4.1 mGy, respectively. In order to investigate the correlation of DRLs with the available imaging modalities (CR, DR and film), this parameter was taken into account. DR imaging DRL is the lowest at 3.5 mGy, CR imaging the highest at 4.2 mGy and film imaging at 3.7 mGy. In order to facilitate comparison with other studies, kerma-width product values were calculated from Ki, air and field size.

Dose surveys and DRLs: critical look and way forward

The main purpose of dose surveys has been to detect and bring down wide variation in radiation doses for any particular radiological examination and to avoid doses that are on higher side. Diagnostic reference levels (DRLs) have been used for over two decades as an aid in this objective. With very limited success that has been achieved through DRL, the author has recently described a new term 'acceptable quality dose' (AQD) that is aimed at optimisation within the DRL, is facility initiated and takes into account all three important parameters-image quality, dose and patient's body build. It is hoped that AQD will be found easy to establish, will be a useful tool to achieve optimisation in the facilities and will serve as the standard dose.

Radiation dose benchmarks during cardiac catheterization for congenital heart disease in the United States

OBJECTIVES

The aim of this study was to define age-stratified, procedure-specific benchmark radiation dose levels during interventional catheterization for congenital heart disease.

BACKGROUND

There is a paucity of published literature with regard to radiation dose levels during catheterization for congenital heart disease. Obtaining benchmark radiation data is essential for assessing the impact of quality improvement initiatives for radiation safety.

METHODS

Data were obtained retrospectively from 7 laboratories participating in the Congenital Cardiac Catheterization Project on Outcomes collaborative. Total air kerma, dose area product, and total fluoroscopy time were obtained for the following procedures: 1) patent ductus arteriosus closure; 2) atrial septal defect closure; 3) pulmonary valvuloplasty; 4) aortic valvuloplasty; 5) treatment of coarctation of aorta; and 6) transcatheter pulmonary valve placement.

RESULTS

Between January 2009 and July 2013, 2,713 cases were identified. Radiation dose benchmarks are presented including median, 75th percentile, and 95th percentile. Radiation doses varied widely between age groups and procedure types. Radiation exposure was lowest in patent ductus arteriosus closure and highest in transcatheter pulmonary valve placement. Total fluoroscopy time was a poor marker of radiation exposure and did not correlate well with total air kerma and dose area product.

CONCLUSIONS

This study presents age-stratified radiation dose values for 6 common congenital heart interventional catheterization procedures. Fluoroscopy time alone is not an adequate measure for monitoring radiation exposure. These values will be used as baseline for measuring the effectiveness of future quality improvement activities by the Congenital Cardiac Catheterization Project on Outcomes collaborative.

A double-blind, randomized, sham-controlled trial of the effect of a radiation-attenuating drape on radiation exposure to endoscopy staff during ERCP

OBJECTIVES

Endoscopic retrograde cholangiopancreatography (ERCP) is associated with radiation exposure to the endoscopist and staff that may be significant in high-volume centers. We investigated whether a radiation-attenuating drape over the fluoroscopy image intensifier reduces radiation exposure during ERCP.

METHODS

We performed a prospective, randomized, double-blind trial of 100 therapeutic ERCPs at a tertiary-care university center. Procedures were randomly assigned to groups receiving lead-free radiation-attenuating drapes (n=50) or identical sham drapes (n=50). The drapes were suspended around the fluoroscopy image intensifier during ERCP. The primary end point was the effective dose of radiation measured at the endoscopist's eye and neck, and at the assisting nurse's neck. The cumulative annual radiation exposure was also estimated.

RESULTS

Fluoroscopy time, absorbed radiation dose, and dose area product were similar in the study groups. Mean effective dose for sham vs. radiation-attenuating drape was 0.21±0.27 vs. 0.02±0.02 mSv at the endoscopist's eye, 0.35±0.44 vs. 0.03±0.03 mSv at the endoscopist's neck, and 0.27±0.34 vs. 0.02±0.02 mSv at the nurse's neck (P<0.0001 for all comparisons). The relative risk reduction in radiation was 90%, 91%, and 93% at the three sites. At a high-volume center in which an endoscopist performs 500 therapeutic ERCPs per year, the estimated cumulative annual effective dose at the endoscopist's eye level is 126 mSv with conventional protection and 12 mSv with a radiation-attenuating drape, with the recommended limit being 20 mSv.

CONCLUSIONS

The addition of a radiation-attenuating drape around the image intensifier during ERCP significantly decreases radiation exposure to endoscopists and staff by ∼90%.

The primary study of low-dose pancreas perfusion by 640- slice helical CT: a whole-organ perfusion

To discuss the feasibility of low-dose whole-pancreas imaging utilizing 640-slice dynamic volume CT.80 patients (40 cases of normal pancreas and 40 patients supposed of having pancreatic carcinoma or focal pancreatic space-occupying lesions were mainly refered) referred for CT pancreas perfusion were enrolled in the study. 80 patients randomly assigned to 3 groups: Group ① (whole sequence). Group ② (odd number sequence). Group ③ (even number group)(Compared to ①, the scanning times and effective radiate dose of ② and ③ decreased about 50% respectively). The head, body, tail of each normal pancreas without any pancreatic disease, lesion and lesion-surrounding areas of each pancreatic cancer were selected as ROI, and tissue peak, blood flow are measured.According to pathology and clinical materials, 27 patients were diagnosed as pancreatic cancer; 40 patients were diagnosed as normal pancreas. The tissue peak and blood flow of the head, body, tail of normal pancreas without any pancreatic disease are 109.63 ± 16.60 and 131.90 ± 41.61, 104.38 ± 19.39 and 127.78 ± 42.52, 104.55 ± 15. 44 and 123.50 ± 33.44 respectively. The tissue peak and blood flow of pancreatic cancer is 59.59 ± 18.20 and 60.00 ± 15.36. For and between each group, there is no significant statistical difference for the tissue peak and blood flow of normal areas of the head, body, tail of normal pancreas. There is statistical difference for the tissue peak and blood flow of lesion and lesion-surrounding areas of pancreatic cancer in each group. However, there is no statistical difference for the tissue peak and blood flow of normal and diseasing areas between 3 groups.Low-dose whole-pancreas perfusion with 640-slice dynamic volume CT is feasible.