Bitewing radiography dosimetry of the PORTRAY stationary-intraoral tomosynthesis imaging system.

OBJECTIVE: This study measured effective (E) and equivalent doses from adult and child 3-dimensional (3D) and 2D posterior bitewing (PBW) examinations using the PORTRAY stationary-intraoral tomosynthesis radiography system. STUDY DESIGN: Adult and child phantoms and optically stimulated luminescent dosimeters were used to measure doses for adult-4 and child-2 projection PBW examinations acquired without (W/O) and with (W) a direct digital sensor in the beam path. Child doses without and with thyroid shielding were measured. RESULTS: Three-dimensional examination E values (µSv) W/O and W were 16.7 and 7.3 for adult, 9.2 and 3.5 for child, and 8.7 and 3.0 with thyroid shielding, respectively. Two-dimensional examination E values W/O and W were 4.3 and 1.5 for adult, 2.1 and 0.6 for child, and 2.0 and 0.5 with shielding, respectively. Sensor presence reduced E for all adult and child examinations (P = .0001). Child E was reduced compared with adult E for both sensor conditions in 3D (P < .0001) and 2D (P ≤ .0043) imaging. Adult and child 3D W/O and W equivalent thyroid doses did not differ (P ≥ .9996). However, child 2D W/O and W doses were lower (P ≤ .0002). Shielding produced no reduction (P ≥ .1128) for either 3D condition or 2D with the sensor (P = .6615) but reduced child 2D dose without the sensor. CONCLUSIONS: Inclusion of a sensor yielded significant reductions in adult and child E. Sensor presence impacted thyroid dose reduction more than shielding.

Pediatric Phantom Dosimetry Evaluation of a New Rectangular Collimator.

Purpose: To compare the effective dose (E) of the Tru-Image® rectangular collimator and the universal round collimator of a Planmeca® wall-mounted radiograph unit for two bitewing radiographs (right and left) on a pediatric phantom.
Methods: Absorbed doses utilizing the Tru-Image ®rectangular collimator and universal round collimator were acquired using an anthropomorphic 10-year-old child phantom. Each set of 24 dosimeters was exposed to two bitewing exposures with the manufacturer's child settings. Fifty clinical exposures were completed for each set and three sets were exposed for each collimator. The average E per exposure was calculated.
Results: The overall E for the Tru-Image ®rectangular collimator and the universal round collimator were 6.3 microsieverts (µSv) and 25.3 µSv, respectively. This difference was statistically significant (P <0.001). The highest equivalent dose for both collimators was delivered to the oral mucosa. When compared to the universal round collimator, the Tru-Image ® rectangular collimator had significant dose reduction at all locations (P <0.05). When normalized and adjusted to the same source-to-end distance, there was an overall 65 percent dose reduction with the rectangular collimator.
Conclusion: The average effective dose was significantly reduced with the use of the Tru-Image ®rectangular collimator. Clinical use of this rectangular collimator should be considered in the pediatric population.

Pediatric Phantom Dosimetry of a Portable Handheld X-ray Device.

The purpose of this study was to quantify radiation dose from the XTG (Xray2Go) handheld X-ray device for bitewing and maxillary anterior occlusal projections using a pediatric phantom. The aim was to evaluate effects of thyroid shielding on total effective dose (E) and tissue equivalent doses (HT) and assess operator backscatter radiation. Methods:A pediatric phantom head with 24 tissue site dosimeters was exposed to radiation from the x-ray device. Exposures included: (1) right and left bitewing (BW) without thyroid collar on phantom, (2) BW with thyroid collar, (3) maxillary anterior occlusal (AO) without thyroid collar, (4) AO with thyroid collar. With each exposure type, new dosimeter sets were used and 30 exposures completed. The operator wore dosimeters on the forehead and right hand to quantify backscatter radiation. Average values of HT and E were calculated. Conclusions: Thyroid shielding made a statistically significant difference for radiation dose with the Xray2Go for BW projections at specific tissue sites, including the thyroid, lymph nodes, and muscle, and for overall effective dose. Radiation to the operator from the device was very low and indistinguishable from background radiation.

Extraoral bite-wing radiographs: A universally accepted paradox.

BACKGROUND: The development of specialized panoramic radiograph machine software has spawned the introduction of an innovative and promising dental radiographic examination type: extraoral bite-wings. But does this unconventional type of imaging belong in the bite-wing family? Is there any relationship at all to the conventional bite-wing radiograph? OBJECTIVES: The purpose of this article is not to make a case for the diagnostic effectiveness of one system over the other; this is best left to further clinical evaluation. Instead, the authors intend to provide an outline of a few key and distinguishing elements of the intraoral bite-wing radiographic examination followed by those of the extraoral panoramic substitute and draw attention to the importance of reimagining the increasingly universal naming convention of this novel radiographic examination, the paradoxical "extraoral bite-wing radiograph", based on the fundamental principles of each of these imaging systems. PRACTICAL IMPLICATIONS: The accuracy of clinical and technical terminology in oral radiography is of paramount importance to both the profession and patients, especially when considering emerging technologies.

Transitioning from pre-clinical to clinical dental radiology, a pilot study: Student perceived influences on confidence.

INTRODUCTION: Producing radiographic images requires the use of ionizing radiation, which has been well documented for its potentially detrimental effects on human tissues. Therefore, dental hygiene students begin their radiographic training by practicing on manikins in a pre-clinical environment. Use of manikins does not allow for patient interaction factors. No published dental studies have examined factors important in helping dental hygiene students develop confidence during the transition from manikins to working with live patients in a clinical radiology setting. PURPOSE/OBJECTIVES: The purpose of this study was to identify students' perceived influences on confidence and ultimately on performance when transitioning from a pre-clinical radiology setting to working with live patients. Specific research questions that were answered by this qualitative study were (1) What pre-clinical radiographic experiences did students feel were beneficial for transitioning from manikins to live patients? (2) What were the primary factors that students felt they struggled with when initially taking radiographs on patients? METHODS: A qualitative study design was implemented in 2017. Data were obtained from students in a 2-year dental hygiene program. Survey responses, focus group feedback, and observation data were used to identify common themes. Emergent themes were reported using frequencies, emic and etic expressions. RESULTS: Four themes surfaced surrounding patient management, communication, appointment mechanics, and infection control. CONCLUSION: The use of standardized simulated patients may enhance clinical preparedness and confidence.

Can modifying shielding, field of view, and exposure settings make the effective dose of a cone-beam computed tomography comparable to traditional radiographs used for orthodontic diagnosis?

OBJECTIVES: To analyze the effect of changes in exposure settings, field of view (FOV), and shielding on radiation to an adult and child phantom from cone-beam computed tomography (CBCT) imaging compared to panoramic and lateral cephalometric radiographs. MATERIALS AND METHODS: The effective dose to an adult and child anthropomorphic phantom by the CS 9300 using various scan protocols was recorded. Absorbed radiation was measured with optically stimulated luminescence dosimeters and effective dose calculated using 2007 International Commission on Radiological Protection tissue weighting factors. Scan protocols included different FOVs, voxel sizes, and standard versus low-dose protocols. Radiation shielding was used when it did not interfere with FOV. Panoramic and lateral cephalometric radiographs were taken with the Orthophos SL. RESULTS: Even with shielding, smaller FOVs, and increased voxel sizes, the effective dose of standard CBCT scans was higher than panoramic and lateral cephalometric radiographs. A shielded limited FOV standard scan combined with a lateral cephalometric radiograph resulted in a lower dose (P < .001) than a full FOV standard scan. Low-dose shielded scans resulted in significant dose reductions to the adult (P < .05) and child (P < .001) phantoms compared to the respective panoramic and lateral cephalometric radiographs combined. Image quality analysis was not possible with radiation equivalent phantoms. CONCLUSIONS: Unlike standard CBCTs, shielded low-dose CBCT protocols in the CS 9300 have lower effective doses than conventional radiographs for adult and child phantoms. If high resolution and cranial base visualization are necessary, combining a shielded LFOV standard exposure with a cephalometric radiograph is recommended.

Intraoral radiographs: A comparison of dose and risk reduction with collimation and thyroid shielding.

BACKGROUND: The National Commission on Radiation Protection and Measurements has reinforced its recommendation for the use of rectangular collimation for intraoral radiography in its Report No. 177 published in 2019. This study compared effective dose (E) using circular and rectangular collimator (RC) modalities. METHODS: The authors exposed 18 projections for adult and 12 projections for child full-mouth series using an original equipment 6 centimeter diameter circular collimator (circular), original equipment rectangular positioning indicator device (Focus-RC), and 5 universal RC modalities (JadRad-RC, Rinn-RC, Durr-RC, DEXshield-RC, and TruAlign-RC) for adult and child phantoms. The authors acquired dosimetry using optically stimulated luminescence dosimeters. Exposures were made with a Focus (Instrumentarium) intraoral source using 70 peak kilovoltage and total milliamperes of 5.34 (adult) and 2.7 (child). RESULTS: Adult E was lowest for Focus-RC (54 microsieverts), which also produced the greatest exposure area reduction (51%) compared with circular, followed by JadRad-RC (55 µSv), Durr-RC (58 µSv), Rinn-RC (62 µSv), DEXshield-RC (70 µSv), TruAlign-RC (85 µSv), and circular (86 µSv). Child E followed a similar trend: Focus-RC (44 µSv), JadRad-RC (44 µSv), Durr-RC (45 µSv), Rinn-RC (48 µSv), DEXshield-RC (53 µSv), TruAlign-RC (85 µSv), and circular (89 µSv). When used with thyroid shielding, circular collimation thyroid dose was reduced by as much as 59%. CONCLUSIONS: Focus-RC techniques yielded the greatest dose reduction compared with alternative RC and circular. In addition to shape, collimator dimensions should be considered as significant factors affecting patient E. RC alone yielded a greater reduction in thyroid dose than did circular with thyroid shielding. PRACTICAL IMPLICATIONS: This study's findings underscore the updated recommendations of the National Commission on Radiation Protection and Measurements Report No.177, which emphasized the benefits and important practical considerations of RC with intraoral imaging.

Bitewing radiography dosimetry of a stationary intraoral tomosynthesis imaging system.

OBJECTIVES: This study assessed effective doses (E) from conventional and stationary intraoral tomosynthesis (s-IOT) radiography for posterior bitewing (PBW) examinations and evaluated the effect of sensor attenuation. STUDY DESIGN: An adult human tissue-equivalent phantom and optically stimulated luminescent dosimeters were used. Series of 4 PBW radiographs were acquired with circular and rectangular collimation. s-IOT PBW radiographs were acquired with built-in rectangular collimation. Radiographs were acquired without and with a sensor in the beam path. RESULTS: E (in µSv) was 15.7 and 8.2 for conventional-circular, 4.6 and 1.1 for conventional-rectangular, and 11.9 and 5.9 for s-IOT in sensor-absent and sensor-present scenarios, respectively. For sensor-absent exposures, E for conventional-rectangular was 29.3% and E for s-IOT was 75.8% of the conventional-circular dose. With the sensor present, these values were 13.4% and 72.0%, respectively (P < .001). Sensor-present E was lower than sensor-absent E for all modalities (P < .001). Reductions in equivalent doses were similar to effective dose reductions. CONCLUSIONS: For PBW examinations, E for s-IOT was smaller than for conventional radiography with circular collimation, but larger than for conventional radiography with rectangular collimation. The presence of a sensor maintained these differences but reduced E for all modalities.

Pediatric Phantom Dosimetry Evaluation of the Extraoral Bitewing.

Purpose: This study's purpose was to evaluate the effective dose (E) and equivalent dose (HT) of exposing a pediatric phantom to the extraoral bitewing programs of the Planmeca ProMax 2D S3 (ProMax) and Instrumentarium Orthopantomograph OP30 (OP30) and compare these results with dosimetry associated with the intraoral bitewing and panoramic radiograph. Methods: Dosimetry was acquired by placing 24 dosimeters in tissues of interest in a 10-year-old phantom. Manufacturer child settings were used for all scans. Repeat exposures of 20 scans were utilized. The average values of E and HT were calculated. Results: The E for the ProMax and OP30 units, respectively, were 16.84 µSv and 5.82 µSv. The highest E for both units was delivered to the thyroid, remainder tissues, and salivary glands. The highest HT for both units was delivered to the oral mucosa, salivary glands, extrathoracic airway, and thyroid. The mean differences between units were statistically significant (P<0.05). Conclusions: The average effective dose of the ProMax was higher than for the OP30. The effective dose of the pediatric extraoral bitewing is three to 11 times higher than that of the intraoral bitewing and comparable to the traditional panoramic radiograph of a pediatric phantom. Pediatric extraoral bitewing radiation protection guidelines are recommended.

A Comparison of Technique Errors using Two Radiographic Intra-oral Receptor-holding Devices.

PURPOSE: Technological advances in intra-oral receptors have resulted in film-holding devices that may or may not be interchangeable with photostimulable phosphor receptors. This study evaluated the number and types of technique errors that occurred when using PSP receptors with a standard film-holding device and a dual PSP/film-designed device. METHODS: The Rinn XCP-ORA® (Standard) and the Rinn Flip-Ray® PA device (Test) were compared using rectangular collimation. DenOptix® imaging plates (sizes 1 and 2) were used as receptors. Fourteen periapical (10-size 2 and 4-size 1) projections were exposed per full mouth series on each Dental X-ray Teaching and Training Replica with both devices. Five Dental X-ray Teaching and Training Replicas were exposed by 3 experienced radiographers. Data were analyzed using a paired t-test to determine differences in the performance scores between the 2 devices. Technique errors (receptor placement, vertical angulation, horizontal angulation and cone centering) were reported using frequencies. An experienced evaluator critiqued each projection. RESULTS: A total of 15 full mouth series (210 projections) were taken per device. The mean performance scores per device were 88.4 (standard device) and 88.1 (test device) and were not statistically different (p=0.88). Cone centering errors were the most common error observed in both the standard (36%) and test (43%) devices. Receptor placement errors occurred when using the standard (12%) and test (9%) devices. Vertical and horizontal errors were <2% for both devices. CONCLUSION: Devices designed for use with film may be used interchangeably with photostimulable phosphor receptors. Some difference was noticed between devices regarding error type and occurrence.

Technical Performance of Universal and Enhanced Intraoral Imaging Rectangular Collimators.

PURPOSE: The purpose of this study was to compare the number and type of technical errors between 2 rectangular collimators, time/motion effort and radiographer preference. METHODS: Subjects (n=17) were recruited to expose an 18 projection full mouth series (FMX) using Tru-Align™ (enhanced) and Rinn® (universal) collimator devices. Both FMXs were exposed using photostimulable phosphor (PSP) digital sensors on a DXTTR manikin with an intraoral x-ray unit. A 5-question survey evaluated ease of device use, time required and device preference. Data were analyzed using frequencies, paired t-test, ANOVA and least squares means using a general linear model. RESULTS: A lower mean number of technique errors per FMX occurred with the enhanced device (9.7) compared to the universal device (12.1). Collimator centering errors occurred 3-times more often with the universal device. The mean numbers of diagnostically unacceptable errors per FMX were similar (Universal=3.2 vs Enhanced=2.9). The least squares means adjusted model showed a statistically significant difference of errors between the 2 devices (p=0.0478) and errors by location when comparing posterior to anterior and posterior to bitewing (p<0.0001). Subjects (94%) preferred the enhanced device and found it easier to use compared to the universal device. Significantly less time was needed to expose an FMX (4 min) when using the enhanced device (p=0.0001). CONCLUSION: The enhanced device enabled subjects to expose diagnostically acceptable radiographs more efficiently with fewer collimator centering errors; however, it does so with a 35% greater exposure area and a concomitant increase in patient dose.

Reducing the risk of intraoral radiographic imaging with collimation and thyroid shielding.

The 2007 modification by the International Commission on Radiation Protection of the calculation of effective dose from ionizing radiation has renewed interest in the concept of As Low As Reasonably Achievable exposure, and the technical approaches for reducing doses. This intraoral imaging study compared effective doses from circular and rectangular collimator modalities. A total of 18-image adult and 12-image child full mouth series were exposed using a 6 cm diameter circular collimator, a universal rectangular collimator, and an enhanced rectangular device for both adult and child phantoms. Rectangular collimation significantly reduced doses for adult exposures. In the child sample, only the universal rectangular collimator achieved significant dose reduction. While dose differences were attributed to both the size of the rectangular field and the use of thyroid shielding, the results indicated that the universal rectangular collimator used alone was more effective at reducing thyroid exposure than a thyroid shield used with circular collimation.