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.

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.

Hand-wrist, knee, and foot-ankle dosimetry and image quality measurements of a novel extremity imaging unit providing CBCT and 2D imaging options.

PURPOSE: Radiation dose is a general concern in diagnostic imaging and a special concern for children who are at greater risk from radiation effects. This study evaluates effective doses (E) produced during 2D and volume imaging with a novel cone beam computed tomography (CBCT) based extremity imaging device. The device's compact size and protocol options offer image choices that enhance the potential for reduced dose and improved diagnostics when evaluating sports injuries. METHODS: Hand-wrist, foot-ankle, and knee phantoms were developed for use with optically stimulated luminescent dosimeters (OSL). Dosimetry of transmission radiographs (2D) and CBCT volumes (3D) was assessed for Standard and lowered dose (Lite) exposure protocols. Effective dose was calculated for child and adult age groups. Image quality was assessed with contrast-to-noise ratio (CNR) and modulation transfer function (MTF). A figure of merit was calculated as the square of CNR divided by E. RESULTS: Standard 2D doses ranged from 0.001-0.06 µSv for adults, 0.001-0.05 µSv for 15-yr olds, 0.003-0.13 µSv for 10-yr olds, and 0.005-0.20 for 5-yr olds. Dose reductions with Lite protocols ranged from 26 to 51%. Standard CBCT doses ranged from 0.3-4.6 µSv for adults, 0.3-4.4 µSv for 15-yr olds, 0.6-9.8 µSv for 10-yr olds, and 1-22.6 µSv for 5-yr olds. For both 2D and 3D a trend of increasing imaging dose with reduced age was present and was statistically significant for children below the age of 10 (P = 0.0009). Lite dose reductions averaged 47%. CNR was statistically reduced in Lite dose scans (P = 0.0384) but was not statistically different using FOM analysis (P = 0.3089). MTF was not significantly affected by the two dose protocols (P = 0.8104). CONCLUSION: CBCT effective doses calculated from anthropomorphic phantom exposures following manufacturer suggested protocols appear to be substantially less than previously reported doses for similar MDCT extremity examinations. In this study, effective dose from 2D radiographic imaging was approximately two orders of magnitude less than CBCT imaging. Doses were on the order of a few minutes to hours of ubiquitous per-capita background dose for 2D imaging and a few hours to days for 3D imaging. Dose significantly increased for children younger than age 10. Lite protocols resulted in substantial dose reductions and can be recommended for children and those examinations where reduced CNR will not affect diagnosis. Flexibility of 2D and 3D imaging options with low-dose protocols make this technology a promising option for radiographic evaluation of the extremities. Efficacy studies are needed to determine when MDCT, CBCT or Digital Radiography are best used for particular diagnostic tasks.

Estimation of effective doses from MDCT and CBCT imaging of extremities.

Little research has been published on the radiation burden of cone beam computed tomography (CBCT) in comparison with multi-row detector computed tomography (MDCT) for extremity imaging. This manuscript reports effective doses produced by standard and reduced dose imaging protocols for a 128-slice MDCT unit and a dedicated extremity imaging device using CBCT technology. Anthropomorphic phantoms with x-ray attenuation characteristics simulating adult hand-wrist, foot-ankle, and knee areas were modified to receive optically stimulated luminescent dosimeters (OSL). Standard and lower kVp reduced dose (Lite) exposures were compared. Effective doses for four age groups (five years old to adult) were calculated following 2007 recommendations of the ICRP. Standard CBCT imaging protocols produced effective doses (1.3-21.1 µSv) that were on the order of daily US ubiquitous background radiation doses. CBCT doses were on average 90% less than comparable MDCT views of the same anatomy (9.1-204 µSv). Child doses were significantly greater than adult doses (p = 0.0001). CBCT doses could be further reduced by 36%-51% with Lite exposure protocols. These protocols can be recommended for children and in cases where increased image noise will not interfere with the diagnostic task.

Pediatric Phantom Dosimetry of Kodak 9000 Cone-beam Computed Tomography.

PURPOSE: The purpose of the study was to evaluate the radiation dose of the Kodak 9000 cone-beam computed tomography (CBCT) device for different anatomical areas using a pediatric phantom. METHODS: Absorbed doses resulting from maxillary and mandibular region three by five cm CBCT volumes of an anthropomorphic 10-year-old child phantom were acquired using optical stimulated dosimetry. Equivalent doses were calculated for radiosensitive tissues in the head and neck area, and effective dose for maxillary and mandibular examinations were calculated following the 2007 recommendations of the International Commission on Radiological Protection (ICRP). RESULTS: Of the mandibular scans, the salivary glands had the highest equivalent dose (1,598 microsieverts [µSv]), followed by oral mucosa (1,263 µSv), extrathoracic airway (pharynx, larynx, and trachea; 859 µSv), and thyroid gland (578 µSv). For the maxilla, the salivary glands had the highest equivalent dose (1,847 µSv), followed closely by oral mucosa (1,673 µSv), followed by the extrathoracic airway (pharynx, larynx, and trachea; 1,011 µSv) and lens of the eye (202 µSv). CONCLUSION: Compared to previous research of the Kodak 9000, completed with the adult phantom, a child receives one to three times more radiation for mandibular scans and two to 10 times more radiation for maxillary scans.

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.

Assessment of phantom dosimetry and image quality of i-CAT FLX cone-beam computed tomography.

INTRODUCTION: The increasing use of cone-beam computed tomography in orthodontics has been coupled with heightened concern about the long-term risks of x-ray exposure in orthodontic populations. An industry response to this has been to offer low-exposure alternative scanning options in newer cone-beam computed tomography models. METHODS: Effective doses resulting from various combinations of field of view size and field location comparing child and adult anthropomorphic phantoms with the recently introduced i-CAT FLX cone-beam computed tomography unit (Imaging Sciences, Hatfield, Pa) were measured with optical stimulated dosimetry using previously validated protocols. Scan protocols included high resolution (360° rotation, 600 image frames, 120 kV[p], 5 mA, 7.4 seconds), standard (360°, 300 frames, 120 kV[p], 5 mA, 3.7 seconds), QuickScan (180°, 160 frames, 120 kV[p], 5 mA, 2 seconds), and QuickScan+ (180°, 160 frames, 90 kV[p], 3 mA, 2 seconds). Contrast-to-noise ratio was calculated as a quantitative measure of image quality for the various exposure options using the QUART DVT phantom. RESULTS: Child phantom doses were on average 36% greater than adult phantom doses. QuickScan+ protocols resulted in significantly lower doses than standard protocols for the child (P = 0.0167) and adult (P = 0.0055) phantoms. The 13 × 16-cm cephalometric fields of view ranged from 11 to 85 µSv in the adult phantom and 18 to 120 µSv in the child phantom for the QuickScan+ and standard protocols, respectively. The contrast-to-noise ratio was reduced by approximately two thirds when comparing QuickScan+ with standard exposure parameters. CONCLUSIONS: QuickScan+ effective doses are comparable with conventional panoramic examinations. Significant dose reductions are accompanied by significant reductions in image quality. However, this trade-off might be acceptable for certain diagnostic tasks such as interim assessment of treatment results.

Attitude of the Korean dentists towards radiation safety and selection criteria.

PURPOSE: X-ray exposure should be clinically justified and each exposure should be expected to give patients benefits. Since dental radiographic examination is one of the most frequent radiological procedures, radiation hazard becomes an important public health concern. The purpose of this study was to investigate the attitude of Korean dentists about radiation safety and use of criteria for selecting the frequency and type of radiographic examinations. MATERIALS AND METHODS: The study included 267 Korean dentists. Five questions related to radiation safety were asked of each of them. These questions were about factors associated with radiation protection of patients and operators including the use of radiographic selection criteria for intraoral radiographic procedures. RESULTS: The frequency of prescription of routine radiographic examination (an example is a panoramic radiograph for screening process for occult disease) was 34.1%, while that of selective radiography was 64.0%. Dentists' discussion of radiation risk and benefit with patients was infrequent. More than half of the operators held the image receptor by themselves during intraoral radiographic examinations. Lead apron/thyroid collars for patient protection were used by fewer than 22% of dental offices. Rectangular collimation was utilized by fewer than 15% of dental offices. CONCLUSION: The majority of Korean dentists in the study did not practice radiation protection procedures which would be required to minimize exposure to unnecessary radiation for patients and dental professionals. Mandatory continuing professional education in radiation safety and development of Korean radiographic selection criteria is recommended.

Dental staff doses with handheld dental intraoral x-ray units.

A handheld portable dental intraoral x-ray system is available in the United States and elsewhere. The system is designed to minimize the user's radiation dose. It includes specially designed shielding of the x-ray tube housing and an integral radiation shield to minimize backscatter. Personnel radiation dose records were obtained from 18 dental facilities using both the handheld system and a wall mounted dental x-ray system, providing 661 individual dose measurements. Dental staff doses were also compared for the handheld and conventional systems using both film and digital imaging for the same facilities and staff members. The results indicate that the doses for the handheld systems are significantly less than for wall-mounted systems. The average monthly dose for the handheld systems was 0.28 µSv vs. 7.86 µSv (deep dose equivalent) for the wall-mounted systems, a difference that is statistically significant at the p = 0.01 level. Consequently, there should be no concern about the use of this handheld dental intraoral x-ray system. Additional shielding efforts, (e.g., wearing a lead apron) will not provide significant benefit nor reduce staff radiation dose.

Incidental findings from cone beam computed tomography of the maxillofacial region: a descriptive retrospective study.

OBJECTIVE: To evaluate the type and prevalence of incidental findings from cone beam computed tomography (CBCT) of the maxillofacial region. Findings are divided into those that require (i) intervention/referral, (ii) monitoring, and (iii) no further evaluation. METHODS: Three hundred consecutive CBCT scans conducted in the University of North Carolina School of Dentistry Oral and Maxillofacial Radiology Clinic from January 1 to August 31, 2008 were retrospectively reviewed. Findings were categorized into airway, soft tissue calcifications, bone, temporomandibular joint (TMJ), endodontic, dental developmental, and pathological findings. RESULTS: A total of 272 scans revealed 881 incidental findings (3.2 findings/scan). The most prevalent was airway findings (35%) followed by soft tissue calcifications (20%), bone (17.5%), TMJ (15.4%), endodontic (11.3%), dental developmental (0.7%), and pathological (0.1%). 16.1% required intervention/referral, 15.6% required monitoring, and the remainder (68.3%) required neither. CONCLUSION: This study underscores the need to thoroughly examine all CBCT volumes for clinically significant findings within and beyond the region of interest.

Comparison of mesiodistal root angulation with posttreatment panoramic radiographs and cone-beam computed tomography.

INTRODUCTION: Orthodontists assess mesiodistal root angulations before, during, and after orthodontic treatment as an aid in establishing proper root position. Panoramic imaging has been useful for this purpose and is a valuable screening tool in diagnosis and planning treatment of orthodontic patients. Cone-beam computed tomography (CBCT) for imaging of the craniofacial complex creates the opportunity to evaluate 3-dimensional images compared with traditional 2-dimensional images. The purpose of this project was to compare mesiodistal root angulations by using posttreatment panoramic radiographic images and CBCT scans. METHODS: Mesiodistal root angulations from panoramic images and CBCT scans of 35 orthognathic surgery patients after orthodontic treatment were compared. The panoramic images were measured by using VixWin (Gendex Dental Systems, Des Plaines, Ill), and the CBCT scans by using InvivoDental 3D (version 4.1, Anatomage, San Jose, Calif). The mesiodistal root angulation of each maxillary and mandibular tooth was measured by using the occlusal plane as the reference line. With an intercept-only linear regression for correlated data (with an unstructured covariance structure), the global test of whether the mean vector of all differences for the teeth is zero was performed separately for the 2 arches. RESULTS: The global test for both arches was statistically significant (P <0.001), indicating an overall difference in root angulation between measurements from panoramic and CBCT images. There was no discernible pattern in the average differences between panoramic and CBCT measurements. CONCLUSIONS: The assessment of mesiodistal tooth angulation with panoramic radiography should be approached with caution and reinforced by a thorough clinical examination of the dentition.

Effective radiation dose of ProMax 3D cone-beam computerized tomography scanner with different dental protocols.

OBJECTIVES: The aim of this study was to compare effective doses resulting from different scan protocols for cone-beam computerized tomography (CBCT) using International Commission on Radiological Protection (ICRP) 1990 and 2007 calculations of dose. STUDY DESIGN: Average tissue-absorbed dose, equivalent dose, and effective dose for a ProMax 3D CBCT with different dental protocols were calculated using thermoluminescent dosimeter chips in a human equivalent phantom. Effective doses were derived using ICRP 1990 and the superseding 2007 recommendations. RESULTS: Effective doses (ICRP 2007) for default patient sizes from small to large ranged from 102 to 298 µSv. The coefficient of determination (R(2)) between tube current and effective dose (ICRP 2007) was 0.90. When scanning with lower resolution settings, the effective doses were reduced significantly (P < .05). CONCLUSIONS: ProMax 3D can provide a wide range of radiation dose levels. Reduction in radiation dose can be achieved when using lower settings of exposure parameters.

Precision of cephalometric landmark identification: cone-beam computed tomography vs conventional cephalometric views.

INTRODUCTION: In this study, we compared the precision of landmark identification using displays of multi-planar cone-beam computed tomographic (CBCT) volumes and conventional lateral cephalograms (Ceph). METHODS: Twenty presurgical orthodontic patients were radiographed with conventional Ceph and CBCT techniques. Five observers plotted 24 landmarks using computer displays of multi-planer reconstruction (MPR) CBCT and Ceph views during separate sessions. Absolute differences between each observer's plot and the mean of all observers were averaged as 1 measure of variability (ODM). The absolute difference of each observer from any other observer was averaged as a second measure of variability (DEO). ANOVA and paired t tests were used to analyze variability differences. RESULTS: Radiographic modality and landmark were significant at P <0.0001 for DEO and ODM calculations. DEO calculations of observer variability were consistently greater than ODM. The overall correlation of 1920 paired ODM and DEO measurements was excellent at 0.972. All bilateral landmarks had increased precision when identified in the MPR views. Mediolateral variability was statistically greater than anteroposterior or caudal-cranial variability for 5 landmarks in the MPR views. CONCLUSIONS: The MPR displays of CBCT volume images provide generally more precise identification of traditional cephalometric landmarks. More precise location of condylion, gonion, and orbitale overcomes the problem of superimposition of these bilateral landmarks seen in Ceph. Greater variability of certain landmarks in the mediolateral direction is probably related to inadequate definition of the landmarks in the third dimension.

Patient risk related to common dental radiographic examinations: the impact of 2007 International Commission on Radiological Protection recommendations regarding dose calculation.

BACKGROUND: In 2007, the International Commission on Radiological Protection (ICRP) revised estimates of the radiosensitivity of tissues including those in the maxillofacial region. The authors conducted a study to reassess patients' risk related to common dental radiographic exposures using the 2007 ICRP recommendations. METHODS: The authors used a tissue-equivalent head phantom to measure dose. They calculated effective doses by using both 1990 and revised 2007 ICRP recommendations. Effective dose is a calculation that takes into consideration the different sensitivities of organs to long-term effects from ionizing radiation. It is the preferred method for comparing doses between different types of exposures. RESULTS: Effective doses (per the 2007 ICRP) in microsieverts were as follows: full-mouth radiographs (FMX) with photo-stimulable phosphor (PSP) storage or F-speed film with rectangular collimation, 34.9 microSv; four-image posterior bitewings with PSP or F-speed film with rectangular collimation, 5.0 microSv; FMX using PSP or F-speed film with round collimation, 170.7 microSv; FMX with D-speed film and round collimation, 388 microSv; panoramic Orthophos XG (Sirona Group, Bensheim, Germany) with charge-coupled device (CCD), 14.2 microSv; panoramic ProMax (Planmeca, Helsinki, Finland) with CCD, 24.3 microSv; posteroanterior cephalogram with PSP, 5.1 microSv; and lateral cephalogram with PSP, 5.6 microSv. These values are 32 to 422 percent higher than those determined according to the 1990 ICRP guidelines. CONCLUSIONS: Although radiographs are an indispensable diagnostic tool, the increased effective doses of common intraoral and extraoral imaging techniques are high enough to warrant reconsideration of means to reduce patients' exposure. CLINICAL IMPLICATIONS: Clinicians can reduce patients' dose substantively by using digital receptors or F-speed film instead of D-speed film, rectangular collimation instead of round collimation and radiographic selection criteria.

Comparative dosimetry of dental CBCT devices and 64-slice CT for oral and maxillofacial radiology.

OBJECTIVES: This study compares 2 measures of effective dose, E(1990) and E(2007), for 8 dentoalveolar and maxillofacial cone-beam computerized tomography (CBCT) units and a 64-slice multidetector CT (MDCT) unit. STUDY DESIGN: Average tissue-absorbed dose, equivalent dose, and effective dose were calculated using thermoluminescent dosimeter chips in a radiation analog dosimetry phantom. Effective doses were derived using 1990 and the superseding 2007 International Commission on Radiological Protection (ICRP) recommendations. RESULTS: Large-field of view (FOV) CBCT E(2007) ranged from 68 to 1,073 microSv. Medium-FOV CBCT E(2007) ranged from 69 to 560 microSv, whereas a similar-FOV MDCT produced 860 microSv. The E(2007) calculations were 23% to 224% greater than E(1990). CONCLUSIONS: The 2007 recommendations of the ICRP, which include salivary glands, extrathoracic region, and oral mucosa in the calculation of effective dose, result in an upward reassessment of fatal cancer risk from oral and maxillofacial radiographic examinations. Dental CBCT can be recommended as a dose-sparing technique in comparison with alternative medical CT scans for common oral and maxillofacial radiographic imaging tasks.