scholarly journals Evaluation of inter- and intra-fraction 6D motion for stereotactic body radiation therapy of spinal metastases: influence of treatment time

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Ahmed Hadj Henni ◽  
David Gensanne ◽  
Maximilien Roge ◽  
Chantal Hanzen ◽  
Guillaume Bulot ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Treatment Time ◽  
Displacement Vector ◽  
Spinal Metastases ◽  
Cone Beam ◽  
Setup Errors ◽  
Maximum Angle ◽  
Fixation Devices ◽  
System 2 ◽  
The Mean

Abstract Background The objective of this study was to analyze the amplitude of translational and rotational movements occurring during stereotactic body radiotherapy (SBRT) of spinal metastases in two different positioning devices. The relevance of intra-fractional imaging and the influence of treatment time were evaluated. Methods Twenty patients were treated in the supine position either (1) on a body vacuum cushion with arms raised and resting on a clegecel or (2) on an integrated SBRT solution consisting of a SBRT table top, an Orfit™ AIO system, and a vacuum cushion. Alignments between the cone beam computed tomography (CBCT) and the planning computed tomography allowed corrections of inter- and intra-fraction positional shifts using a 6D table. The absolute values of the translational and rotational setup errors obtained for 329 CBCT were recorded. The translational 3D vector, the maximum angle, and the characteristic times of the treatment fractions were calculated. Results An improvement in the mean (SD) inter-fraction 3D vector (mm) from 7.8 (5.9) to 5.9 (3.8) was obtained by changing the fixation devices from (1) to (2) (p < 0.038). The maximum angles were less than 2° for a total of 87% for (1) and 96% for (2). The mean (SD) of the intra-fraction 3D vectors (mm) was lower for the new 1.1 (0.8) positioning fixation (2) compared to the old one (1) 1.7 (1.7) (p = 0.004). The angular corrections applied in the intra-fraction were on average very low (0.4°) and similar between the two systems. A strong correlation was found between the 3D displacement vector and the fraction time for (1) and (2) with regression coefficients of 0.408 (0.262–0.555, 95% CI) and 0.069 (0.010–0.128, 95% CI), respectively. An accuracy of 1 mm would require intra-fraction imaging every 5 min for both systems. If the expected accuracy was 2 mm, then only system (2) could avoid intra-fractional imaging. Conclusions This study allowed us to evaluate setup errors of two immobilization devices for spine SBRT. The association of inter- and intra-fraction imaging with 6D repositioning of a patient is inevitable. The correlation between treatment time and corrections to be applied encourages us to move toward imaging modalities which allow a reduction in fraction time.

scholarly journals Intraoperative cone beam computed tomography for detecting residual stones in percutaneous nephrolithotomy: a feasibility study

Urolithiasis ◽  
2021 ◽  
Author(s):  
R. A. Kingma ◽  
M. J. H. Voskamp ◽  
B. H. J. Doornweerd ◽  
I. J. de Jong ◽  
S. Roemeling
Keyword(s):  
Computed Tomography ◽  
Percutaneous Nephrolithotomy ◽  
Cone Beam Computed Tomography ◽  
University Hospital ◽  
Cone Beam ◽  
Cross Sectional ◽  
The Mean ◽  
Residual Stones ◽  
Residual Fragments

AbstractCone beam computed tomography (CBCT) provides multiplanar cross-sectional imaging and three-dimensional reconstructions and can be used intraoperatively in a hybrid operating room. In this study, we investigated the feasibility of using a CBCT-scanner for detecting residual stones during percutaneous nephrolithotomy (PCNL). Intraoperative CBCT-scans were made during PCNL procedures from November 2018 until March 2019 in a university hospital. At the point where the urologist would have otherwise ended the procedure, a CBCT-scan was made to image any residual fragments that could not be detected by either nephroscopy or conventional C-arm fluoroscopy. Residual fragments that were visualized on the CBCT-scan were attempted to be extracted additionally. To evaluate the effect of this additional extraction, each CBCT-scan was compared with a regular follow-up CT-scan that was made 4 weeks postoperatively. A total of 19 procedures were analyzed in this study. The mean duration of performing the CBCT-scan, including preparation and interpretation, was 8 min. Additional stone extraction, if applicable, had a mean duration of 11 min. The mean effective dose per CBCT-scan was 7.25 mSv. Additional extraction of residual fragments as imaged on the CBCT-scan occurred in nine procedures (47%). Of the follow-up CT-scans, 63% showed a stone-free status as compared to 47% of the intraoperative CBCT-scans. We conclude that the use of CBCT for the detection of residual stones in PCNL is meaningful, safe, and feasible.

scholarly journals Height difference between the vestibular and palatal walls and palatal width: a cone beam computed tomography approach

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
P. López-Jarana ◽  
C. M. Díaz-Castro ◽  
A. Falcão ◽  
C. Falcão ◽  
J. V. Ríos-Santos ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Cone Beam ◽  
Bone Thickness ◽  
Height Difference ◽  
Mean Values ◽  
The Mean ◽  
Maxilla And Mandible ◽  
Palatal Bone ◽  
Two Parameters

Abstract Background The objective of this study was to measure two parameters involved in tri-dimensional implant planning: the position of the buccal and palatal bone wall and the palatal thickness. Methods Cone beam computed tomography (CBCT) images (Planmeca ProMax 3D) of 403 teeth (208 upper teeth and 195 lower teeth) were obtained from 49 patients referred to the Dental School of Seville from January to December 2014. The height difference between the palatal and buccal walls was measured on the most coronal point of both walls. The thickness of the palatal wall was measured 2 mm from the most coronal point of the palatal wall. Results The mean values in the maxilla were 1.7 ± 0.9 mm for central and lateral incisors, 2.2 ± 1.7 mm for canines, 1.6 ± 0.9 mm for premolars and 1.9 ± 1.5 mm for molars. In the lower jaw, the mean values were 1.3 ± 0.8 mm for incisors, 1.7 ± 1.2 mm for canines, 2.3 ± 1.3 mm for premolars, and 2.6 ± 1.7 mm for molars. In the upper jaw, more than 55% of maxillary teeth (excluding second premolars and molars) presented mean height differences greater than 1 mm. In the mandible, more than 60% of incisors showed a buccal bone thickness of 1 mm from the apical to lingual aspect. All teeth except the second premolar presented a buccal wall located more than 1 mm more apically than the lingual bone wall. Conclusions The buccal bone wall is located more apically (greater than 1 mm) than the palatal or lingual table in most of the cases assessed. The thickness of the palatal or lingual table is also less than 2 mm in the maxilla and mandible, except in the upper canines and premolars and the lower molars.

Ionizing radiation and its considerations in imaging diagnosis: comparison of absorbed dose between cone beam computed tomography and multi-detector computed tomography in the head and neck

2021 ◽  
Author(s):  
P.L.E. Oliveira ◽  
C.R. Starling ◽  
C.L.P. Maurício ◽  
F.R. Guedes ◽  
M.A. Visconti ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Head And Neck ◽  
Cone Beam Computed Tomography ◽  
Absorbed Dose ◽  
Cone Beam ◽  
Thermoluminescent Dosimeters ◽  
Organ Tissue ◽  
The Mean ◽  
Average Adult ◽  
Multi Detector Computed Tomography

Introduction: The objective of this study was to compare the mean absorbed dose in patients undergoing head and neck examinations using two cone beam computed tomography (CBCT, Kodak and i-CAT) and one multi-detector computed tomography (MDCT). Methods: Three thermoluminescent dosimeters (TLDs), calibrated in air kerma, were positioned in 24 regions of the head and neck of a phantom simulating an average adult. The mean absorbed dose (mGy) values in these positions, for different organs and tissues, were obtained using correction factors, considering the ratio between the mass energy absorption coefficients of organ/tissue and air. Comparison between radiation doses in the most radiosensitive regions was done by calculating the ratio of these dose values, with propagated uncertainty. Results: The dose in all regions was significantly higher for MDCT when compared to CBCT. Concerning CBCT equipment, the Kodak device had a higher absorbed dose than the i-CAT for most of the regions tested. The uncertainty of the i-CAT was greater than that of the Kodak. Conclusion: Due to the considerable difference between absorbed doses, emphasizing the higher dose values obtained in MDCT, the dissemination of CBCT application in medicine is recommended, as well as further studies to broaden the criteria for use.

scholarly journals Comparison of the Hounsfield Unit Values Obtained From Cone-Beam Computed Tomography (CBCT) and Multidetector Computed Tomography (MDCT) Images for Different Bone Densities

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
Atefeh Khavid ◽  
Mojgan Sametzadeh ◽  
Mostafa Godiny ◽  
Mohammad Mehdi Moarrefpour
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Pearson Correlation ◽  
Hounsfield Unit ◽  
Cone Beam ◽  
Ct Scanner ◽  
Significance Level ◽  
Dental Practitioners ◽  
Significant Difference ◽  
The Mean

Background and objective: In recent years, cone-beam computed tomography (CBCT) has become a key diagnostic tool in dentistry. CBCT can provide 3D images of the maxillofacial area to help dental practitioners in diagnosis and treatment, especially implant placement and treatment of pathogenic lesions. This study aimed to compare the Hounsfield Unit (HU) values obtained from CBCT images for bones of different densities with the corresponding HU values from MDCT images. Materials and methods: cube-shaped bone blocks of identical size were cut from the middle section of the cow ribs and femur area such that they had a layer of cortical bone in their buccal, lingual, and top surfaces and trabecular bone in the middle. MDCT scans were performed using a Somatom Sensation Ct Scanner. After determining HU from the results of these scans, nine suitable specimens from different ranges of HU were chosen for comparison. HU of the CBCT images was computed by the dedicated software of the CBCT machine. Finally, HU values obtained from MDCT and CBCT were compared. Data analysis was performed using SPSS version 25 at the 0.05 significance level. Results: The results showed a statistically significant difference between the mean HU from MDCT images and the mean HU from CBCT images (P<0.05). For similar specimens, CBCT produced higher mean HU values than MDCT. The Pearson correlation test detected a significant direct relationship between the HU values of specimens in MDCT and CBCT (P<0.05). Conclusion: For the tools and software used in this study, there was no significant difference between the HU values obtained from MDCT and CBCT, but the mean HU obtained from CBCT was higher than that from MDCT.

Postoperative Assessment of Incisor Dental Implants Using Cone-Beam Computed Tomography

2010 ◽  
Vol 36 (5) ◽  
pp. 377-384 ◽  
Author(s):  
Munetaka Naitoh ◽  
Hiromitsu Nabeshima ◽  
Hisashi Hayashi ◽  
Takehiko Nakayama ◽  
Kenichi Kurita ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Dental Implants ◽  
Cone Beam Computed Tomography ◽  
Bone Grafts ◽  
Cone Beam ◽  
Postoperative Assessment ◽  
Labial Side ◽  
Bone To Implant Contact ◽  
The Mean ◽  
Postoperative Findings

Abstract The bone configuration surrounding anterior dental implants was postoperatively assessed using cone-beam computed tomography (CBCT). In 21 patients with a mean age of 41.5 years, 36 implants placed in the incisor region were postoperatively evaluated using CBCT. The rate of bone-to-implant contact (%) was calculated. The mean rate of bone-to-implant contact on the labial side was 78.3% with and 65.3% without bone grafts. The postoperative findings of incisor implants could be assessed using CBCT.

scholarly journals Palatal Soft Tissue Thickness on Maxillary Posterior Teeth and Its Relation to Palatal Vault Angle Measured by Cone-Beam Computed Tomography

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Doosadee Hormdee ◽  
Thanwarat Yamsuk ◽  
Pipop Sutthiprapaporn
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Cone Beam ◽  
Tissue Thickness ◽  
Posterior Teeth ◽  
Power Of Test ◽  
Soft Tissue Thickness ◽  
Mucosal Thickness ◽  
The Mean ◽  
Palatal Vault

Objective. Analyzing palatal soft tissue thickness in cone-beam computed tomography (CBCT) images and evaluating the relationship between tissue thickness and palatal vault angulation. Methods. Out of 1,737 CBCT images, fifty-six images met the inclusion criteria and were included in this cross-sectional study. The palatal vault angle on the maxillary first molar was measured and divided the images into 3 groups. The soft tissue thickness between the maxillary first premolar and second molar was measured at a distance of 3, 6, 7, 8, and 9 mm from the cementoenamel junction. All the image measurements were performed using CBCT-viewer software. Result. In this study, 56 CBCT images with full permanent maxillary posterior teeth and absence of light scattering were found. The mean age of the patients was 31.59 ± 13.92 years. The moderate and deep palatal vault angle patterns had the greatest and least prevalence, respectively. The average thickness on shallow, moderate, and deep palatal vault groups was 4.02 ± 0.58, 3.75 ± 0.73, and 3.43 ± 0.38 mm, respectively. Furthermore, the mean palatal mucosal thickness was statistically different between the deep and shallow palatal vault angle groups (p<0.05, power of test 0.8). Based on the Pearson correlation coefficient, there was a negative correlation between the palatal mucosal thickness and palatal vault angle (p<0.05, power of test 0.85). Conclusion. A negative correlation between the palatal mucosal thickness and palatal vault angle was observed. Furthermore, this study suggested that the shape of the palatal vault can be one of the supporting data for evaluating the graft dimensions.

scholarly journals Cone Beam Computed Tomography-Based Anatomical Assessment of the Olfactory Fossa

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Andre Luiz Ferreira Costa ◽  
Aline Kataki Paixão ◽  
Bianca Costa Gonçalves ◽  
Celso Massahiro Ogawa ◽  
Thiago Martinelli ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Cross Sectional Study ◽  
Cone Beam ◽  
Type I ◽  
Type Ii ◽  
Sectional Study ◽  
Cross Sectional ◽  
Computed Tomography Images ◽  
The Mean

This study aimed to investigate the olfactory fossa according to the Keros classification using cone beam computed tomography. This cross-sectional study analysed cone beam computed tomography images selected from a database belonging to a radiology centre. The scans of 174 healthy patients were analysed by using the Xoran software. Gender, age, and side were correlated with the Keros classification. The mean age of the 174 patients was 45.3 years. The most prevalent Keros classification was type II (65.52%), followed by type III (20.69%) and type I (13.79%). No significant differences were found between Keros classification and the variables age, right side (pvalue = 0.4620), and left side (pvalue = 0.5709). There were also no significant differences between gender and the variables right side (pvalue = 0.1421) and left side (pvalue = 0.2136). Based on these results, we suggest that cone beam computed tomography can be recommended for analysis of the anterior skull base. Keros type II was the most prevalent type in our sample.

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