Search

Background: Administration of external radiation therapy via proton therapy systems carries a risk of occasional collisions between the patient's body and gantry, which is increased by the snout placed near the patient for better dose distribution. Although treatment planning software (TPS) can simulate controlled collisions, the computed tomography (CT) data used for treatment planning are insufficient given that collisions can occur outside the CT imaging region. Thus, imaging the three‐dimensional (3D) surface outside the CT range and combining the data with those obtained by CT are essential for avoiding collisions. Purpose: To construct a prototype for 3D surface imaging and an end‐to‐end framework for preventing collisions between the patient's body and the gantry. Methods: We obtained 3D surface data using a light sectioning method (LSM). By installing only cameras in front of the CT, we achieved LSM using the CT couch motion and preinstalled patient‐positioning lasers. The camera image contained both sagittal and coronal lines, which are unnecessary for LSM and were removed by deep learning. We combined LSM 3D surface data and original CT data to create synthetic Digital Imaging and Communications in Medicine (DICOM) data. Subsequently, we compared the TPS snout auto‐optimization using the original CT data with the synthetic DICOM data. Results: The mean positional error for LSM of the arms and head was 0.7 ± 0.8 and 0.8 ± 0.8 mm for axial and sagittal imaging, respectively. The TPS snout auto‐optimization indicated that the original CT data would cause collisions; however, the synthetic DICOM data prevented these collisions. Conclusions: The prototype system's acquisition accuracy for 3D surface data was approximately 1 mm, which was sufficient for the collision simulation. The use of a TPS with collision avoidance can help optimize the snout position using synthetic DICOM data. Our proposed method requires no external software for collision simulation and can be integrated into the clinical workflow to improve treatment planning efficiency. [ABSTRACT FROM AUTHOR]

Objective: To the knowledge of the authors, no data about the reproducibility and accuracy of 3‐dimensional surface imaging of the face using a whole‐body scanner are available. Thus, the objective of this investigation was to assess the reproducibility of facial scans acquired using a whole‐body imaging device. Material and Methods: This investigation investigated 220 3‐D scans of a total of 22 healthy volunteers (with a mean age of 29.36 years). Two consecutive 3‐D images using a Vectra WB360 of the volunteers were obtained utilizing a whole‐body imaging device. Predefined distances in the face were performed in each scan and compared. Furthermore, surface deviation between two consecutively captured scans was assessed. Results: The distance with the smallest statistical significance was found to be at the nose with p = 0.998, while the biggest statistical significance was found in the midface with p = 0.658. The area with the biggest surface deviation between the superimposed scans was the neck with a root mean square (RMS) of 1.62 ± 1.71, and the area with the smallest surface deviation was the forehead with a RMS of 0.17 ± 0.05. Conclusion: The whole‐body imaging device investigated in this study can be utilized to capture the face and provides enough accuracy to compare scans. Even though not directly investigated, it can be hypothesized that the error caused by repositioning the patient between a baseline and a follow‐up scan will not be too big to consider measurements performed with the whole‐body imaging device as impractical. [ABSTRACT FROM AUTHOR]

Introduction: We investigated the correlation between optical surface imaging using a three‐dimensional (3D) scanner and magnetic resonance imaging (MRI) for suggesting feasibility in the clinical process of tracking volume changes in head and neck patients during radiation treatment. Methods: Ten patients were divided into two groups depending on the location of their tumor (i.e., right or left side). With weekly imaging data, the change in volume based on MRI was evaluated during the treatment course. Four volumes of interest (VOIs) were calculated on the 3D surface image of the facial and cervical areas using an optical 3D scanner, and the correlation between volumetric parameters were analyzed. Results: The target volume changed significantly overall for both groups. The changes parotid volume reduced by up to 3.8% and 28.0% for groups A (right side) and B (left side), respectively. In Group A, VOI 1 on the facial area and VOI 3 on the cervical area decreased gradually during the treatment course by up to 3.3% and 10.7%, respectively. In Group B, only VOI 4 decreased gradually during the treatment course and reduced by up to 9.2%. In group A, the change in target volume correlated strongly with right‐side parotid, VOI 1, and VOI 3, respectively. The parotid also showed strong correlations with VOIs (P < 0.01). The weight loss was strongly correlated with either PTV or parotid without statistical significance (P > 0.05). In group B (left side), the change in target volume correlated strongly with each volumetric parameter, including weight loss. For individual patient, PTV showed more correlation with VOIs on the cervical area than VOIs on the facial area. Conclusions: An optical 3D scanner can be applied to track changes in volume without radiation exposure during treatment and the optical surface image correlated with MRI. [ABSTRACT FROM AUTHOR]

Gross thigh volume is a key anthropometric variable to predict sport performance and health. Currently, it is either estimated by using the frustum method, which is prone to high inter-and intra-observer error, or using medical imaging, which is expensive and time consuming. Depth camera 3D-imaging systems offer a cheap alternative to measure thigh volume but no between-session reliability or comparison to medical imaging has been made. This experiment established between-session reliability and examined agreement with magnetic resonance imaging (MRI). Forty-eight male cyclists had their thigh volume measured by the depth camera system on two occasions to establish between-session reliability. A subset of 32 participants also had lower body MRIs, through which agreement between the depth camera system and MRI was established. The results showed low between-session variability (CV = 1.7%; Absolute Typical Error = 112 cm3) when measuring thigh volume using the depth camera system. The depth camera systematically measured gross thigh volume 32.6cm3 lower than MRI. These results suggest that depth camera 3D-imaging systems are reliable tools for measuring thigh volume and show good agreement with MRI scanners, providing a cheap and time-saving alternative to medical imaging analysis. [ABSTRACT FROM AUTHOR]

The use non-ionizing three-dimensional (3D) imaging in cleft lip and palate is an emerging field, but properly designed methods for the assessment of these images are not well established. Therefore, the aim of this study was to review the current literature on the modalities of assessment of non-ionizing 3D images for the quantification of facial morphology, symmetry, and appearance in cleft lip and palate, and to assess the method error of these modalities. A systematic literature search was conducted using MEDLINE (PubMed), Cochrane Central Register of Controlled Trials, Web of Science, and Embase. Cross-sectional studies with prospective or retrospective data collection, using non-ionizing 3D imaging, with a subjective or objective outcome assessment and including at least 10 cleft lip and/or palate patients were considered eligible. Overall, 1767 unique studies were identified and 33 met the inclusion criteria. The images were objectively assessed using elementary measurements and comprehensive statistical methods for superimposition, shape description, and structuring. Subjective assessment was performed using a Likert-type scale or visual analogue scale. It can be concluded that non-ionizing 3D images are widely used in cleft research, but 3D analysis of the images is often methodologically suboptimal. Researchers must fully utilize the content of 3D images to quantify morphology, symmetry, and appearance. [ABSTRACT FROM AUTHOR]

Complex anthropometrics such as area and volume, can identify changes in body size and shape that are not detectable with traditional anthropometrics of lengths, breadths, skinfolds and girths. However, taking these complex with manual techniques (tape measurement and water displacement) is often unsuitable. Three-dimensional (3D) surface imaging systems are quick and accurate alternatives to manual techniques but their use is restricted by cost, complexity and limited access. We have developed a novel low-cost, accessible and portable 3D surface imaging system based on consumer depth cameras. The aim of this study was to determine the validity and repeatability of the system in the measurement of thigh volume. The thigh volumes of 36 participants were measured with the depth camera system and a high precision commercially available 3D surface imaging system (3dMD). The depth camera system used within this study is highly repeatable (technical error of measurement (TEM) of <1.0% intra-calibration and ~2.0% inter-calibration) but systematically overestimates (~6%) thigh volume when compared to the 3dMD system. This suggests poor agreement yet a close relationship, which once corrected can yield a usable thigh volume measurement. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To investigate the heart position variability in deep-inspiration breath-hold (DIBH) radiation therapy (RT) for breast cancer when 3D surface imaging would be used for monitoring the BH depth during treatment delivery. For this purpose, surface setup data were compared with heart setup data. Materials and methods: Twenty patients treated with DIBH-RT after breast-conserving surgery were included. Retrospectively, heart registrations were performed for cone-beam computed tomography (CBCT) to planning CT. Further, breast-surface registrations were performed for a surface, captured concurrently with CBCT, to planning CT. The resulting setup errors were compared with linear regression analysis. Furthermore, geometric uncertainties of the heart (systematic [Σ] and random [σ]) were estimated relative to the surface registration. Based on these uncertainties planning organ at risk volume (PRV) margins for the heart were calculated: 1.3Σ −0.5σ. Results: Moderate correlation between surface and heart setup errors was found: R 2 =0.64, 0.37, 0.53 in left–right (LR), cranio-caudal (CC), and in anterior–posterior (AP) direction, respectively. When surface imaging would be used for monitoring, the geometric uncertainties of the heart (cm) are [Σ =0.14, σ =0.14]; [Σ =0.66, σ =0.38]; [Σ =0.27, σ =0.19] in LR; CC; AP. This results in PRV margins of 0.11; 0.67; 0.25cm in LR; CC; AP. Conclusion: When DIBH-RT after breast-conserving surgery is guided by the breast-surface position then PRV margins should be used to take into account the heart-position variability relative to the breast-surface. [Copyright &y& Elsevier]

Abstract: Purpose: To investigate the accuracy of surface imaging for monitoring intrafraction motion purposes in frameless stereotactic body radiotherapy (SBRT) of lung cancer by comparison with cone-beam computed tomography (CBCT). Materials and methods: Thirty-six patients (18 males, 18 females) were included. During each fraction, three CBCT scans were acquired; CBCT1: before treatment, CBCT2: after correction for tumor misalignment, and CBCT3: after treatment. Intrafraction motion was derived by registering CBCT2 and CBCT3 to the mid-ventilation planning CT scan. Surfaces were captured concurrently with CBCT acquisitions. Retrospectively, for each set of surfaces, an average surface was created: Surface1, Surface2, and Surface3. Subsequently, Surface3 was registered to Surface2 to assess intrafraction motion. For the differences between CBCT- and surface-imaging-derived 3D intrafraction motions, group mean, systematic error, random error and limits of agreement (LOA) were calculated. Results: Group mean, systematic and random errors were smaller for females than for males: 0.4 vs. 1.3, 1.3 vs. 3.1, and 1.7 vs. 3.3mm respectively. For female patients deviations between CBCT-tumor- and 3D-surface-imaging-derived intrafraction motions were between −3.3 and 4.3mm (95% LOA). For male patients these were substantially larger: −5.9–9.5mm. Conclusion: Surface imaging is a promising technology for monitoring intrafraction motion purposes in SBRT for female patients. [Copyright &y& Elsevier]

Abstract: This study develops an objective breast symmetry evaluation using 3-D surface imaging (Konica-Minolta V910® scanner) by superimposing the mirrored left breast over the right and objectively determining the mean 3-D contour difference between the 2 breast surfaces. 3 observers analyzed the evaluation protocol precision using 2 dummy models (n = 60), 10 test subjects (n = 300), clinically tested it on 30 patients (n = 900) and compared it to established 2-D measurements on 23 breast reconstructive patients using the BCCT.core software (n = 690). Mean 3-D evaluation precision, expressed as the coefficient of variation (VC), was 3.54 ± 0.18 for all human subjects without significant intra- and inter-observer differences (p > 0.05). The 3-D breast symmetry evaluation is observer independent, significantly more precise (p < 0.001) than the BCCT.core software (VC = 6.92 ± 0.88) and may play a part in an objective surgical outcome analysis after incorporation into clinical practice. [Copyright &y& Elsevier]

Summary: Background: Changes in breast-morphology occur after all types of breast surgery, but a systematic and objective surgical result assessment is currently lacking. Three-dimensional (3-D) surface imaging offers the ability to quantitatively evaluate breast contour, shape, surface and volume changes after surgery. This study evaluates 3-D breast contour and volume changes after breast augmentation over time. Methods: 3-D surface imaging of 14 subpectoral breast-augmentation patients (n = 28 breasts) were accomplished over six time periods (preoperative (OP), post-OP 1: 2–3 days; post-OP 2: 1 week; post-OP 3: 1 month; post-OP 4: 3 months; and post-OP 5: 6 months after surgery) and linear-distance measurement, breast volume and surface changes were analysed. 3-D breast-contour- and volume variations are expressed in percentage changes over time. Results: All breast measurements changed significantly between pre-OP and post-OP 1 (Friedmann test, p = 0.001–0.025). First significant postoperative changes over time compared with post-OP 1 for breast volume, surface, sternal notch to nipple and nipple to inframammary-fold-distance measurements are quantifiable after 1 month (post hoc Wilcoxon test, p = 0.001 for all) with further relevant breast volume (post hoc Wilcoxon test, p = 0.041) and surface changes (post hoc Wilcoxon test, p = 0.037) between months 1 and 3 after surgery. The inframammary fold dropped by 1.4 cm after 6 months and final breast volume ± 0.5% is reached between months 1 and 3 after surgery. Valuable reductions in breast contour and volume by nearly 85% are also reached after 1 month (Wilcoxon test, p = 0.001) and changed to 98% after 3 months and 100% after 6 months. Conclusions: Breast morphological changes following subpectoral breast augmentation are completed after 3 months. 3-D surface imaging may play a part in comparing different breast-augmentation techniques. [Copyright &y& Elsevier]

Surface imaging is in use in radiotherapy clinical practice for patient setup optimization and monitoring. Breast alignment is accomplished by searching for a tentative spatial correspondence between the reference and daily surface shape models. In this study, the authors quantify whole breast shape alignment by relying on texture features digitized on 3D surface models. Texture feature localization was validated through repeated measurements in a silicone breast phantom, mounted on a high precision mechanical stage. Clinical investigations on breast shape alignment included 133 fractions in 18 patients treated with accelerated partial breast irradiation. The breast shape was detected with a 3D video based surface imaging system so that breathing was compensated. An in-house algorithm for breast alignment, based on surface fitting constrained by nipple matching (constrained surface fitting), was applied. Results were compared with a commercial software where no constraints are utilized (unconstrained surface fitting). Texture feature localization was validated within 2 mm in each anatomical direction. Clinical data show that unconstrained surface fitting achieves adequate accuracy in most cases, though nipple mismatch is considerably higher than residual surface distances (3.9 mm vs 0.6 mm on average). Outliers beyond 1 cm can be experienced as the result of a degenerate surface fit, where unconstrained surface fitting is not sufficient to establish spatial correspondence. In the constrained surface fitting algorithm, average surface mismatch within 1 mm was obtained when nipple position was forced to match in the [1.5; 5] mm range. In conclusion, optimal results can be obtained by trading off the desired overall surface congruence vs matching of selected landmarks (constraint). Constrained surface fitting is put forward to represent an improvement in setup accuracy for those applications where whole breast positional reproducibility is an issue. [ABSTRACT FROM AUTHOR]