Dental staff doses with handheld dental intraoral x-ray units

Image Quality Assessment of Digital Radiographs Captured by Hand-Held Devices Versus Wall-Mounted Devices: A Retrospective Comparative Study

Background In diagnostic radiology, the image quality of radiographs is paramount for impeccable diagnosis as it is essential for efficient treatment planning and patient care. In comparison to their well-established wall-mounted equivalents, the growing use of handheld devices raises concerns regarding their diagnostic effectiveness by questioning their image quality. Hence, to fully comprehend the clinical importance of handheld X-ray equipment, it is important to look into their image quality for better diagnostic performance. Aim The study aimed to determine the image quality of handheld X-ray units and compare them with wall-mounted X-ray units in routine dental practice based on objectifiable image quality parameters. Materials and Methods For the study, 200 digital radiographic images (102 taken using handheld and 98 using wall-mounted X-ray units) were collected randomly from archives, including radiographs with cone-cut and positional errors. Five observers, three faculty members, and two postgraduates, who were all blinded, subjectively judged the image quality using a five-point rating scale for five individual parameters: contrast, sharpness, cone-cut, and error in vertical and horizontal angulations of position indicating device separately. The mean score for all observers was calculated, and statistical analysis was performed using the Mann-Whitney U test. The scoring of one faculty member experienced in oral radiology as baseline data was used to compare interobserver agreement among the other observers. Results There is a significant difference between the two groups in cone-cut and error in horizontal angulation. There is no significant difference between the two groups when parameters such as contrast, sharpness, and error in vertical angulation are considered. The images from handheld devices showed better image quality (p = 0.006) compared to the wall-mounted device. There was 87% interobserver agreement between the five observers. Conclusion The present study demonstrated a significant difference between the handheld device and the wall-mounted device when all the five parameters including errors are considered to assess the image quality. Hence, handheld devices can be used for regular clinical practice as an alternative to wall-mounted devices. Nevertheless, stringent radiation safety precautions are essential.

APPLICATION OF THE MONTE CARLO METHOD FOR THE EVALUATION OF SCATTERED RADIATION DOSE DUE TO THE USE OF HANDHELD X-RAY IN DENTISTRY

The object of this study was to evaluate the dose of scattered radiation in the organs of the operator and assistant located in different positions within a dental room when acquiring intraoral images with a portable handheld X-ray device, using Monte Carlo simulations for recommended and traditional techniques. A typical dental installation was modeled, where the operator and assistant were placed. The beam is represented by 60-kV spectrum. Ten scenarios were simulated, representing different positions and use of the lead apron. The results of the simulations were carried out with typical parameters of the annual workload, showing significant increases in dose in the organs of the operator due to the angulation. The minimum dose in the organs of the assistant occurred when he was located 2-m away and 45° from the direction of the beam. The dose received by the operator is significantly reduced with the use apron.

Accuracy in positioning of dental X-ray images - A comparative study of a portable X-ray device and a wall-mounted device

Introduction

The benefits of portable dental X-ray devices remain controversially debated. This study aimed to compare the accuracy in positioning dental X-ray images using handheld (Nomad Pro 2) and wall-mounted (Heliodent Plus) X-ray devices.

Materials and methods

Radiographical imaging was exercised on a maxillofacial phantom using the handheld dental X-ray device Nomad Pro 2 (Kavo Kerr, Biberach, Germany) and the wall-mounted dental X-ray device Heliodent Plus (Sirona Dental Systems, Bensheim, Germany). Accuracy of device positioning (i.e., centeredness and perpendicularity) was measured as horizontal and vertical deviation (pixels and millimeters) from a centrally positioned crosshair. The reproducibility of the results was tested for 80 images per device and operator. IBM SPSS (SPSS Inc., Chicago, IL) was used for statistical analyses.

Results

Centeredness of produced dental X-rays was significantly better for the wall-mounted device than for the handheld device in both deviation from the x-axis (p = 0.042) and y-axis (p = 0.020). The perpendicularity of the produced dental X-rays was significantly better for the handheld device than for the wall-mounted device for both horizontal (p < 0.001) and vertical (p < 0.001) plains.

Conclusions

Handheld dental X-ray devices appear to provide a high degree of accuracy in image positioning, especially in regard to proper perpendicular image angulation.

Diagnostic image quality of hand-held and wall-mounted X-ray devices in bitewing radiography: a non-inferiority clinical trial

OBJECTIVES

The present clinical trial was intended to clarify whether subjective assessments of diagnostic X-ray image quality achieved via hand-held (HH) Nomad Pro 2 (KaVo Kerr, Brea, CA, USA) X-ray device is non-inferior that of the wall-mounted (WM) KaVo Focus (KaVo Dental, Bieberich, Germany).

METHODS

A prospective, cross-over, and in vivo non-inferiority clinical trial was conducted to compare these two diagnostic modalities. Based on sampling calculations, 205 patients were selected for study, generating 410 paired bitewing radiographs in randomized sequence. The films were assessed independently, engaging three observers blinded to modality for random, side-by-side-comparisons. Diagnostic image quality was rated as follows: no preference, HH preference, or WM preference. Observer judgements were combined accordingly to reach a majority.

RESULTS

Collective observer ratings indicated no preference for diagnostic image quality in 63.9% of cases, with WM preference at 16.6% and HH preference at 19.5%. The difference in HH and WM preferences (19.5%-16.6% = 2.9%) was within the expected 95% confidence interval. Majority agreement was reached in 82.7%.

CONCLUSIONS

Subjectively assessed diagnostic image quality in bitewing radiographs acquired by HH and WM devices did not differ significantly. The hand-held device is thus non-inferior to the WM in this regard. Our data set of paired bitewing radiographs may subsequently aid in future research.

Evaluation of radiation exposure to operators of portable hand-held dental X-ray units

The use of hand-held dental X-ray units is increasing within Australia since their portability is advantageous in applications such as aged care. However, proximity of the operator to the X-ray unit raises radiation safety concerns. The aim of this study was to evaluate operator radiation exposure and methods of dose reduction for the Rextar X camera-style hand-held dental X-ray unit. Leakage and scattered radiation were measured using a solid state detector. Scatter was generated using a Perspex head phantom. Measurements of scattered radiation dose as a function of distance were made with and without a lead acrylic scatter shield (0.6 mm Pb equivalence at 100 kVp) attached to the X-ray unit. Without the scatter shield, doses to the operator from a single adult maxillary molar X-ray exposure were 0.69, 0.78 and 0.47 µGy at the left hand, right hand and eyes respectively. With the scatter shield attached, doses were reduced to 0.25, 0.12 and 0.15 µGy respectively, corresponding to a dose reduction of 64, 85 and 68%. The contribution from leakage radiation was insignificant in comparison. It is highly unlikely that an operator would reach occupational dose limits when using the Rextar X hand-held dental X-ray unit, even without the scatter shield in place. Nevertheless, it is strongly recommended that the scatter shield is attached to keep operator doses as low as reasonably achievable. Use of the scatter shield additionally ensures compliance with the Australian legislative requirement for a protective barrier and is considered a preferable alternative to X-ray protective clothing.

Radiodense bullet wipe around osseous entrance gunshot wounds

"Bullet wipe" is the material deposited by a bullet on any surface with which it comes into contact after it is fired and may contain debris from the gun barrel, including particles of primer and metal fragments from previously fired bullets. X-ray analysis is a non-destructive method by which traces of metallic elements can be visually detected. The analysis of osseous defects for radiodense bullet wipe (RBW) assists in determining the presence or absence of perforating gunshot wounds, especially in fragmented, skeletonized remains. The aim of our current study was to determine the frequency of RBW around entrance firearms injuries that perforated bone. We prospectively analyzed entrance gunshot wounds for RBW over a three-year period using digital X-ray analysis (n = 59). We retrospectively reviewed the corresponding autopsy reports to determine the frequency of RBW by biologic sex, reported ancestry, age-at-death, location of wound, manner of death, range of fire, bullet caliber, and presence of bullet jacket. Data were analyzed by Fisher's exact test or Chi-square test with significance levels accepted at p < 0.05. RBW was present in 66% (n = 39) of examined cases. Decedent characteristics did not significantly alter RBW distribution, including biologic sex (p = 0.75), reported ancestry (p = 0.49), and age-at-death (p = 0.43). Additionally, the location of the osseous entrance gunshot wound, manner of death, range of fire, and cartridge caliber did not affect RBW detection. All cases involving non-jacketed rounds (n = 5) showed RBW (p = 0.30). To our knowledge, this study is the first to report the frequency of RBW detection from osseous entrance gunshot wounds.

Comparison of air dose and operator exposure from portable X-ray units

This study was aimed at investigating and comparing exposure dose of workers and the surrounding workers. In addition, worker's exposure was also measure about lens and finger. Four intraoral portable X-ray units were evaluated. The stray radiations were measured using Pitman 37D and ionization chamber (Pitman). MyDosemini (ALOKA) was used for measurement of the finger exposure dose. Without the shield became high in anterior 0.5 m. Comparing the air dose for the four models used in this study showed a high tendency for the two NOMAD models. And using the shields, the images could be taken 4.6 times of the baseline at a maximum and 3.6 times on average. The finger radiation exposure dose was low with both of the NOMAD models, with no significant difference found. By setting the baseline value without a shield, finger radiation exposure when using a shield was lower than the detection limit for the D3000, and was reduced by approximately 94-96% for other three models. All models can photograph around 100 bodies, so it is considered that it is not necessary to switch out the operator considering the operation limit. But even if it does not reach the operation limit, the stochastic effects of radiation exposure can be increased as well as the deterministic effects of the operation limit. The operator and the surrounding workers seek to protect themselves. It is important to perform exposure management that takes into account the stochastic effects to the operator and the surrounding workers.

Image quality of a portable X-ray device (Nomad Pro 2) compared to a wall-mounted device in intraoral radiography

OBJECTIVES

The aim of this study was to determine whether a handheld (HH) X-ray device (Nomad Pro 2) is capable of producing equivalent or even superior X-ray image quality in comparison to a wall-mounted (WM) dental X-ray unit (Heliodent Plus) on the basis of objectifiable image quality parameters.

METHODS

Anatomical, radiological and biological dental X-ray image quality parameters of a handheld dental X-ray device (Nomad Pro 2, Kavo Kerr, Biberach, Germany) were compared to a standard wall-mounted dental X-ray unit (Heliodent Plus, Sirona Dental Systems, Bensheim, Germany) using a maxillofacial phantom. In addition, the effect of different operators (dentists, dental students, dental assistants) on the dental X-ray image quality was measured.

RESULTS

HH and WM devices showed comparable image quality for anterior teeth, premolars, molars and bitewing images. During the two-month investigational period, the radiation exposure level for the operator of the Nomad Pro 2 was 0.1 mSv for 203 images. Dentists as the highest trained personnel enrolled in the study achieved better image quality with the Nomad Pro 2 as compared to dental students and dental assistants, especially in the molar region.

CONCLUSIONS

A HH device delivers a comparable image quality to a WM device. In addition, there seem to be short learning curves with regard to image acquisition when using a handheld device, which is further minimised by the previous training of the operating personnel. HH dental X-ray devices, such as the Nomad Pro 2 are a promising adjunct for dental radiology in cases where WM units are of limited practicability.

Precision of aiming with a portable X-ray device (Nomad Pro 2) compared to a wall-mounted device in intraoral radiography

METHODS AND MATERIALS

20 operators obtained intraoral radiographs of four regions (bitewing, upper molar, lower molar and upper anterior) in five mannequins, using HH and WM devices. Beam-aiming devices were fitted with metal cross-wires to project on image sensors. Deviation from ideal perpendicular incidence of beam was calculated, based on positions of cross-wires relative to gold-standard positions (i.e. average of 10-fold precise aiming by authors via WM system). Analytic models relied on Wilcoxon signed-rank test and mixed model analyses.

RESULTS

Mean deviations from perfect aim were 2.88˚ (± 1.80˚) for WM and 3.06˚ (± 1.90˚) for HH methods. The difference among all operators (HH vs WM) was 0.17˚ (± 2.48˚), which was not significant. Seven operators showed better aim by HH device (13 by WM system); and in one instance, this difference was significant.

CONCLUSIONS

Aiming precision proved similar for HH and WM methods of intraoral radiography, although individual operators may perform better using one of these modalities. Aim is not an expected limiting factor for image quality in HH (vs WM) diagnostics.

Evaluation of stray radiation to the operator for five hand-held dental X-ray devices

OBJECTIVES

Evaluate stray radiation to the operator, as represented by a plane within the significant zone of occupancy (SZO), produced by five models of hand-held intraoral dental X-ray devices (HIDXDs).

METHODS

The stray radiation for five models of HIDXDs was measured, using an anthropomorphic tissue-equivalent head phantom as a scattering object. An ionization chamber was used to measure the air kerma (μGy) at 63 positions in a 160 cm high by 60 cm wide plane that was 10 cm behind the X-ray device, identified as being within the SZO.

RESULTS

Based on the measured air kerma from stray radiation of five different HIDXDs, the estimated annual air kerma at all measured spatial positions was calculated. When calculated using a median air kerma of 0.8 mGy at the distal end of the cone, as typically required for digital image receptors, ¹ the ranges for estimated annual air kerma in the SZO across the devices were 0.14-0.77 mGy for the median, 0.41-1.01 mGy for the mean, and 1.32-2.55 mGy for the maximum. Similarly, when calculated using a median air kerma of 1.6 mGy as typically required for D-speed film, ² the ranges for estimated annual air kerma across the devices were 0.28-1.54 mGy for the median, 0.83-2.03 mGy for the mean, and 2.64-5.10 mGy for the maximum.

CONCLUSIONS

From measured air kerma values of stray radiation in the SZO, estimated annual exposures to the operator for HIDXDs are expected to be greater than from conventional wall-mounted or portable devices activated from a protected area (at a distance or behind shielding). HIDXDs should therefore only be used when patient accessibility makes their use necessary and the use of a portable device on a stand or a wall-mounted device is not reasonably feasible. This approach would keep occupational radiation exposures of dental workers as low as reasonably achievable.

Operator safety during the acquisition of intraoral images with a handheld and portable X-ray device

OBJECTIVES

The present study aims at investigating different radiation protection issues and dose values while acquiring intraoral images with a handheld X-ray device.

METHODS

An Aribex NOMAD Pro 2™, a RANDO^® male head phantom, a consistency testing body, a PTW NOMEX^® Multimeter, and a PTW Farmer^® Ionization Chamber Type 30,010 were used to investigate: (1) dose area products; (2) the expansion of the control area (CA); (3) the scattering pattern and (4) the potential risk for operators of the X-ray device.

RESULTS

Dose area products at different exposure times were distributed linearly with a high correlation factor (>0.9). At 4000 simulated exposures, the greatest extent of the CA was 42 cm (mean = 16.7 cm, SD = 10.8 cm). The highest occurrence of scattering radiation resulted between the RANDO^® phantom and the X-ray device. No scattered radiation was measured at the dorsal part of the phantom or on the operator site of a virtual vertical plane through the focal spot of the X-ray.

CONCLUSIONS

Through this study, we could demonstrate that the application of an Aribex NOMAD Pro 2 device for intraoral imaging does not increase the risk for the operator if the device is controlled according to the manufacturer's specifications. Furthermore, we were able to show that the CA was significantly smaller than specified by European and other international radiation protection standards.

The effects of device position on the operator's radiation dose when using a handheld portable X-ray device

INTRODUCTION

Handheld X-ray devices are now offered in dental practice. Handheld X-ray units challenge the concept of a restricted access to the "controlled area" as they are held by the operator. Although an integral lead shield is provided, the distance from the body is variable, dependent on how the device is held. The aim of this article was to investigate the level of operator dose when using a handheld X-ray device in various positions.

MATERIAL AND METHODS

A NOMAD Pro™ Handheld X-ray system (Aribex Inc., Charlotte, NC) fitted with a remote control and mounted on a tripod was used in this study. A maxillofacial phantom ATOM(®) Max Dental and Diagnostic Phantom, model 711 HN (CIRS Inc., Norfolk, VA) was used to simulate the patient's head position. A mannequin was used to represent the operator. Pre-calibrated thermoluminescent dosemeters (TLDs) (Qados, Agar Scientific, Stansted, UK) were placed on the mannequin close to the eyes and at the level of thyroid, trunk, waist, hand (right finger + left palm) and feet, and three TLDs were used for background radiation. Three test scenarios were investigated; Position 1, close to operators' body and parallel to the ground; Position 2, away from the body with the arms fully extended (approximately 40 cm distance) and parallel to the ground; Position 3, perpendicular to the ground while the arms are partially extended. 30 exposures each of 1 s were performed in each test.

RESULTS

Background radiation was measured at 0.0110 mGy. The highest exposure after subtracting background radiation was recorded on the palm of the left hand (0.0310 mGy) at Position 3. The estimated dose to the operator was calculated based on an average workload of 100 intraoral radiographs weekly for a dental practitioner working 46 weeks a year.

CONCLUSIONS

There is a negligible increase in operator exposure levels using handheld X-ray devices which remain well below the recommended levels of the Ionizing Radiation Regulations 1999. They could however represent an increase from what should be a nil exposure when using a wall-mounted machine. The position of the device relative to the operator has a significant effect on the overall operator's radiation exposure. The use of personal dosemeters is highly recommended to ensure a continuity of low radiation dose exposure. Furthermore, guidance, training and protocols on usage must be in place, strictly adhered to and regular audits are necessary to ensure compliance.

The reduction methods of operator's radiation dose for portable dental X-ray machines

Objectives

This study was aimed to investigate the methods to reduce operator's radiation dose when taking intraoral radiographs with portable dental X-ray machines.

Materials and Methods

Two kinds of portable dental X-ray machines (DX3000, Dexcowin and Rextar, Posdion) were used. Operator's radiation dose was measured with an 1,800 cc ionization chamber (RadCal Corp.) at the hand level of X-ray tubehead and at the operator's chest and waist levels with and without the backscatter shield. The operator's radiation dose at the hand level was measured with and without lead gloves and with long and short cones.

Results

The backscatter shield reduced operator's radiation dose at the hand level of X-ray tubehead to 23 - 32%, the lead gloves to 26 - 31%, and long cone to 48 - 52%. And the backscatter shield reduced operator's radiation dose at the operator's chest and waist levels to 0.1 - 37%.

Conclusions

When portable dental X-ray systems are used, it is recommended to select X-ray machine attached with a backscatter shield and a long cone and to wear the lead gloves.

Maintaining radiation exposures as low as reasonably achievable (ALARA) for dental personnel operating portable hand-held x-ray equipment

Clinical experience indicates that newly available portable hand-held x-ray units provide advantages compared to traditional fixed properly installed and operated x-ray units in dental radiography. However, concern that hand-held x-ray units produce higher operator doses than fixed x-ray units has caused regulatory agencies to mandate requirements for use of hand-held units that go beyond those recommended by the manufacturer and can discourage the use of this technology. To assess the need for additional requirements, a hand-held x-ray unit and a pair of manikins were used to measure the dose to a simulated operator under two conditions: exposures made according to the manufacturer's recommendations and exposures made according to manufacturer's recommendation except for the removal of the x-ray unit's protective backscatter shield. Dose to the simulated operator was determined using an array of personal dosimeters and a pair of pressurized ion chambers. The results indicate that the dose to an operator of this equipment will be less than 0.6 mSv y⁻¹ if the device is used according to the manufacturer's recommendations. This suggests that doses to properly trained operators of well-designed, hand-held dental x-ray units will be below 1.0 mSv y⁻¹ (2% of the annual occupational dose limit) even if additional no additional operational requirements are established by regulatory agencies. This level of annual dose is similar to those reported as typical dental personnel using fixed x-ray units and appears to satisfy the ALARA principal for this class of occupational exposures.