Image-guided Methods Research Articles

Relationship Between the Superior Nuchal Line and the Lower Edge of the Transverse Sinus

Even if image-guided methods have been used, surface landmarks are still important references in retrosigmoid craniotomy. The superior nuchal line (SNL) was thought to be roughly parallel to and below the lower edge of the transverse sinus (LETS). We intended to determine the relationship between the SNL and the LETS and verify the reliability of the SNL in locating the LETS. In total 72 human skull sides, the relationship between the SNL and the LETS was studied. The SNL was roughly parallel to and below the LETS in only 27 sides (37.5%) in our study. Totally, the SNL was roughly parallel to or just over the LETS in 81.9% of all sides. The SNL was obviously unparallel to the LETS in 13 sides (18.1%). Of the 13 sides, 6 difference types of relationship between the SNL and the LETS could be found. In our study, we got different result: the relationship between the SNL and the LETS seemed to be more variable; however, the SNL is still a useful surface landmark in retrosigmoid craniotomies. But considering the anatomic variability, it should be individualized by combining surface landmarks with image-guided methods.

Decreasing Suprapubic Tube-Related Injuries: Results of Case Series and Comprehensive Literature Review

Bowel-related injuries are known complications of suprapubic tube (SPT) catheterization placement. A literature review was conducted to determine identifiable risk factors for bowel injury. Results on the analysis of 25 cases are presented along with a proposed algorithm to aid in choosing between open, percutaneous, and image-guided methods of placement.

The accuracy of pedicle screw placement using intraoperative image guidance systems

Several retrospective studies have demonstrated higher accuracy rates and increased safety for navigated pedicle screw placement than for free-hand techniques; however, the accuracy differences between navigation systems has not been extensively studied. In some instances, 3D fluoroscopic navigation methods have been reported to not be more accurate than 2D navigation methods for pedicle screw placement. The authors of this study endeavored to identify if 3D fluoroscopic navigation methods resulted in a higher placement accuracy of pedicle screws. A systematic analysis was conducted to examine pedicle screw insertion accuracy based on the use of 2D, 3D, and conventional fluoroscopic image guidance systems. A PubMed and MEDLINE database search was conducted to review the published literature that focused on the accuracy of pedicle screw placement using intraoperative, real-time fluoroscopic image guidance in spine fusion surgeries. The pedicle screw accuracy rates were segregated according to spinal level because each spinal region has individual anatomical and morphological variations. Descriptive statistics were used to compare the pedicle screw insertion accuracy rate differences among the navigation methods. A total of 30 studies were included in the analysis. The data were abstracted and analyzed for the following groups: 12 data sets that used conventional fluoroscopy, 8 data sets that used 2D fluoroscopic navigation, and 20 data sets that used 3D fluoroscopic navigation. These studies included 1973 patients in whom 9310 pedicle screws were inserted. With conventional fluoroscopy, 2532 of 3719 screws were inserted accurately (68.1% accuracy); with 2D fluoroscopic navigation, 1031 of 1223 screws were inserted accurately (84.3% accuracy); and with 3D fluoroscopic navigation, 4170 of 4368 screws were inserted accurately (95.5% accuracy). The accuracy rates when 3D was compared with 2D fluoroscopic navigation were also consistently higher throughout all individual spinal levels. Three-dimensional fluoroscopic image guidance systems demonstrated a significantly higher pedicle screw placement accuracy than conventional fluoroscopy or 2D fluoroscopic image guidance methods.

Patterns of Care for the Definitive Management of Prostate Cancer in the U.S.

although a trend toward towards statistical significance was found for increasing GI toxicity in patients with diabetes (HR 2.40, 95% CI, 0.99-5.77, p Z 0.05). Conclusions: This is the first study to compare the GS-EPID and EM-T methods of image guidance for prostate IMRT. Overall, the rates of GU and GI toxicity and BF were low in both groups despite RT dose escalation. There were no differences observed between the GS-EPID and EM-T groups in terms of toxicity or outcome. Longer follow-up is needed to determine the effect of IGRT method on long-term toxicity and BF. Author Disclosure: L. Chang: None. T. Li: None. E. Horwitz: None. D.Y.T. Chen: None. R. Viterbo: None. A. Kutikov: None. R. Greenberg: None. M.K. Buyyounouski: None.

Defect recognition in crystalline silicon solar cells by X-ray tomosynthesis with layer resolution

The increasing demand for higher quality in solar cell production led to the development of several inline control methods. Beneath the image-guided methods, X-ray is not yet very well investigated for the application in photovoltaic research but shows high potential. In contrast to the ordinary X-ray radioscopic method, the tomosynthesis technique exhibits additional depth information of the solar cells and modules. In this article, several applications of tomosynthesis for the investigation of solar cells and modules are studied. It will be shown what potential the application of X-ray and especially tomosynthesis has as quality control tool for photovoltaics. Copyright © 2013 John Wiley & Sons, Ltd.

CT-guided nerve block: a review of the features of CT fluoroscopic guidance for nerve blocks

Nerve blocks are an attractive interventional therapy in pain medicine. Several image guidance methods are available to secure the safety, accuracy, and selectivity of the nerve block. Computed tomography (CT) guidance provides a clear view of the vital viscera and vessels that should be avoided by the needle, and accurate placement of the needle tip before neuro-destructive procedures. A recent advance in CT technology is multi-slice CT fluoroscopy, which allows for rapid and easy correction of needle tip placement during insertion. To reduce the radiation dose for both patients and staff, the lowest radiation setting, intermittent quick-check fluoroscopy, and shortening of the planning scan should be used. Preliminary CT scanning with excellent spatial resolution may facilitate the application of CT fluoroscopic guidance to various types of nerve blocks. Here we review celiac plexus and splanchnic nerve blocks, trigeminal nerve block, neurolytic sympathectomy, and spinal intervention performed under CT guidance. Additional large-scale studies are needed to optimize the use of image guidance, especially CT fluoroscopy guidance, for nerve blocks.

SU-E-U-09: Direct Clinical Comparison of 2D Versus 3D Transabdominal Ultrasound Image Guidance Methods for Prostate Radiotherapy Treatment

Purpose: Direct clinical comparison of 2D versus 3D transabdominal ultrasound image guidance (USIG) methods for prostate radiotherapy Methods: Image guidance shifts were compared on the same subject, same treatment session between Nomos BAT and Elekta Clarity ultrasound methods for 20 patients and 662 prostate treatments. Both systems use unique approaches to USIG. BAT system acquires two static 2D ultrasound images (axial and sagittal) and compares them to contours derived from simulation CT (i.e. intermodality comparison). Clarity system acquires a 3D ultrasound data set at CT simulation and compares to treatment‐day 3D ultrasound image set for deriving image guidance shifts (i.e. intramodality comparison). In this study, transabdominal Clarity image guidance was performed and the shifts were implemented first. Then transabdominal ultrasound images were acquired approximately 1minute later with BAT to derive image guidance shifts. These BAT‐reported shifts were recorded as the difference between BAT and Clarity USIG. The same experienced operator performed both BAT and Clarity paired alignments. Results: The average differences between the two systems were less than 1.0 mm in all three principle directions. The average standard deviation of these differences in lateral, vertical, and longitudinal direction were 1.2, 1.7, and 1.4 mm, respectively. Average Max difference (across all patients) was 1.9 mm; absolute Max across all image sessions was 10.2 mm. Differences between the two USIG approaches can be partially explained by prostate motion as a function of the time elapsed between imaging sessions, and 10.2 mm Max is not inconsistent with prostate motion we have observed during a similar time frame when using Calypso RF tracking. Results were further stratified into two groups: intact prostate and post‐prostatectomy, and no systematic differences were observed between these two groups. Conclusion: Good agreement was observed in this head‐to‐head comparison study between BAT and Clarity USIG methods for prostate localization.

A novel dose‐based positioning method for CT image‐guided proton therapy

Proton dose distributions can potentially be altered by anatomical changes in the beam path despite perfect target alignment using traditional image guidance methods. In this simulation study, the authors explored the use of dosimetric factors instead of only anatomy to set up patients for proton therapy using in-room volumetric computed tomographic (CT) images. To simulate patient anatomy in a free-breathing treatment condition, weekly time-averaged four-dimensional CT data near the end of treatment for 15 lung cancer patients were used in this study for a dose-based isocenter shift method to correct dosimetric deviations without replanning. The isocenter shift was obtained using the traditional anatomy-based image guidance method as the starting position. Subsequent isocenter shifts were established based on dosimetric criteria using a fast dose approximation method. For each isocenter shift, doses were calculated every 2 mm up to ± 8 mm in each direction. The optimal dose alignment was obtained by imposing a target coverage constraint that at least 99% of the target would receive at least 95% of the prescribed dose and by minimizing the mean dose to the ipsilateral lung. The authors found that 7 of 15 plans did not meet the target coverage constraint when using only the anatomy-based alignment. After the authors applied dose-based alignment, all met the target coverage constraint. For all but one case in which the target dose was met using both anatomy-based and dose-based alignment, the latter method was able to improve normal tissue sparing. The authors demonstrated that a dose-based adjustment to the isocenter can improve target coverage and/or reduce dose to nearby normal tissue.

PO-0942: Comparison of different image-guidance methods in patients with pelvic malignancies

PO-0942: Comparison of different image-guidance methods in patients with pelvic malignancies

Incidence of and risk factors for superior facet violation in minimally invasive versus open pedicle screw placement during transforaminal lumbar interbody fusion: a comparative analysis

A reported risk factor for adjacent-segment disease is injury to the superior facet joint from pedicle screw placement. Given that the facet joint is not typically visualized during percutaneous pedicle screw insertion, there is a concern for increased facet violation (FV) in minimally invasive fusion procedures. The purpose of this study was to analyze and compare the incidence of FV among patients undergoing minimally invasive transforaminal lumbar interbody fusion (MITLIF) and open transforaminal lumbar interbody fusion (TLIF). The impact of O-arm navigation compared with traditional fluoroscopy on FV in MITLIF is also assessed, as are risk factors for FV. The authors identified a consecutive population of patients who underwent MITLIF with percutaneous pedicle screw placement, as well as a matched cohort of patients who underwent open TLIF. Postoperative CT imaging was assessed to determine intraarticular FV due to pedicle screw placement. Patients were stratified into minimally invasive and open TLIF groups. Within the MITLIF group, the authors performed a subanalysis of image guidance methods used in cases of FV. Two-tailed Student t-test, ANOVA, chi-square testing, and logistic regression were used for statistical analysis. A total of 282 patients were identified, with a total of 564 superior pedicle screw placements. The MITLIF group consisted of 142 patients with 284 screw insertions. The open TLIF group consisted of 140 patients with 280 screw insertions. Overall, 21 (7.4%) of 282 patients experienced FV. A total of 21 screws violated a facet joint for a screw-based FV rate of 3.7% (21 of 564 screws). There were no significant differences between the MITLIF and open TLIF groups in the percentage of patients with FV (6.3% vs 8.6%) and or the percentage of screws with FV (3.2% vs 4.3%) (p = 0.475 and p = 0.484, respectively). Further stratifying the MI group into O-arm navigation and fluoroscopic guidance subgroups, the patient-based rates of FV were 10.8% (4 of 37 patients) and 4.8% (5 of 105 patients), respectively, and the screw-based rates of FV were 5.4% (4 of 74 screws) and 2.4% (5 of 210 screws), respectively. There was no significant difference between the subgroups with respect to patient-based or screw-based FV rates (p = 0.375 and p = 0.442, respectively). The O-arm group had a significantly higher body mass index (BMI) (p = 0.021). BMI greater than 29.9 was independently associated with higher FV (OR 2.36, 95% CI 1.65-8.53, p = 0.039). The findings suggest that minimally invasive pedicle screw placement is not associated with higher rates of FV. Overall violation rates were similar in MITLIF and open TLIF. Higher BMI, however, was a risk factor for increased FV. The use of O-arm fluoroscopy with computer-assisted guidance did not significantly decrease the rate of FV.

Image-Guided Techniques Improve the Short-Term Outcome of Autologous Osteochondral Cartilage Repair Surgeries: An Animal Trial.

Objective:Autologous osteochondral cartilage repair is a valuable reconstruction option for cartilage defects, but the accuracy to harvest and deliver osteochondral grafts remains problematic. We investigated whether image-guided methods (optically guided and template guided) can improve the outcome of these procedures.Design:Fifteen sheep were operated to create traumatic chondral injuries in each knee. After 4 months, the chondral defect in one knee was repaired using (a) conventional approach, (b) optically guided method, or (c) template-guided method. For both image-guided groups, harvest and delivery sites were preoperatively planned using custom-made software. During optically guided surgery, instrument position and orientation were tracked and superimposed onto the surgical plan. For the template-guided group, plastic templates were manufactured to allow an exact fit between template and the joint anatomy. Cylindrical holes within the template guided surgical tools according to the plan. Three months postsurgery, both knees were harvested and computed tomography scans were used to compare the reconstructed versus the native pre-injury joint surfaces. For each repaired defect, macroscopic (International Cartilage Repair Society [ICRS]) and histological repair (ICRS II) scores were assessed.Results:Three months after repair surgery, both image-guided surgical approaches resulted in significantly better histology scores compared with the conventional approach (improvement by 55%, P < 0.02). Interestingly, there were no significant differences found in cartilage surface reconstruction and macroscopic scores between the image-guided and the conventional surgeries.

Real-time X-ray-based 4D image guidance of minimally invasive interventions

A new technology is introduced that enables real-time 4D (three spatial dimensions plus time) X-ray guidance for vascular catheter interventions with acceptable levels of ionising radiation. The enabling technology is a combination of low-dose tomographic data acquisition with novel compressed sensing reconstruction and use of prior image information. It was implemented in a prototype set-up consisting of a gantry-based flat detector system. In pigs (n = 5) angiographic interventions were simulated. Radiation dosage on a per time base was compared with the "gold standard" of X-ray projection imaging. Contrary to current image guidance methods that lack permanent 4D updates, the spatial position of interventional instruments could be resolved in continuous, spatial 4D guidance; the movement of the guide wire as well as the expansion of stents could be precisely tracked in 3D angiographic road maps. Dose rate was 23.8 μGy/s, similar to biplane standard angiographic fluoroscopy, which has a dose rate of 20.6 μGy/s. Real-time 4D X-ray image-guidance with acceptable levels of radiation has great potential to significantly influence the field of minimally invasive medicine by allowing faster and safer interventions and by enabling novel, much more complex procedures for vascular and oncological minimally invasive therapy. • Real-time 4D (three spatial dimensions plus time) angiographic intervention guidance is realistic. • Low-dose tomographic data acquisition with special compressed sensing-based algorithms is enabled. • Compared with 4D CT fluoroscopy, this method reduces radiation to acceptable levels. • Once implemented, vascular interventions may become safer and faster. • More complex intervention approaches may be developed.

Chest Drainage

Infectious, traumatic, or neoplastic processes in the chest often result in fluid collections within the pleural, parenchymal, or mediastinal spaces. The same fundamental principles that guide drainages of the abdomen can be applied to the chest. This review discusses various pathologic conditions of the thorax that can result in the abnormal accumulation of fluid or air, and their management using image-guided methods.

Phase I/II Study of Radiologic Hepatic Arterial Infusion of Fluorouracil Plus Systemic Irinotecan for Unresectable Hepatic Metastases from Colorectal Cancer: Japan Clinical Oncology Group Trial 0208-DI

PurposeTreatment of patients who have metastatic colorectal cancer (CRC) by using a combination of hepatic arterial infusion chemotherapy (HAIC) and systemic chemotherapy has resulted in promising clinical outcomes. Additionally, image-guided HAIC is reported to be less invasive and distribute drugs more accurately than surgical HAIC. The purpose of this study was to assess the combination of image-guided delivery of fluorouracil through HAIC and systemic irinotecan in a multicenter phase I/II study. Materials and MethodsTwenty-five patients with unresectable liver metastases from CRC were fitted with hepatic arterial catheter and port systems by using image-guided methods. Intraarterial fluorouracil (1,000 mg/m2) was administered on days 1, 8, and 15 of each treatment cycle. The dose of systemic irinotecan on days 1 and 15 was escalated from 75 mg/m2. ResultsNo dose-limiting toxicity was encountered during phase I, and the recommended dose of irinotecan was set at 150 mg/m2. Grade 3 or higher adverse events included hyperglycemia (15%), elevated γ-glutamyl transpeptidase levels (15%), and neutropenia (9%). The response rate and median survival time were 72% and 49.8 months (95% CI, 27.5–78.1 mo), respectively. ConclusionsThe combination of image-guided delivery of fluorouracil through HAIC and systemic irinotecan yielded favorable safety, response rate, and survival results. This combination should be evaluated in a large study.

Abstract 5725: Accuracy of off-line bioluminescence imaging to localize targets in pre-clinical radiation research

Abstract Introduction Pre-clinical methods of delivering focal radiation to biological targets have made significant advances. Our group has developed the Small Animal Radiation Research Platform (SARRP), which is capable of using x-ray cone-beam CT (CBCT) to accurately guide delivery of conformal radiation. However, CBCT is deficient in localizing small orthotopic soft-tissue tumors. Bioluminescent imaging (BLI) is an affordable, accessible and sensitive ancillary method of detecting such tumors. In this study, we evaluate the setup accuracy of off-line BLI as a means to guide focal irradiation of small tumor volumes. Methods Athymic nude mice were used in accordance with institutional guidelines. Human pancreatic carcinoma cells (MiaPaCa-2) stably expressing luciferase were injected into a small glass bulb and sutured intra-abdominally to the tail of the pancreas in euthanized mice. Two methods of animal repositioning were employed during this process in which the animals were either unrestrained (n=6) or restrained (n=5). Two dimensional (2D) BLI and 3D bioluminescent tomography (BLT) were acquired of each supine mouse carcass. An ink-dot marked the “visual” centroid of the surface BL image. Carcasses were then transported to a SARRP for CBCT localization. Three methods of image guidance were applied. Using visual setup, the animal was positioned to align the ink-dot with the central axis of the SARRP. In the CBCT-aided setup, the pose of each carcass was adjusted to recapitulate its pose at the time of BLI. The 2D radial offset of the “true” bulb centroid in CBCT from the central axis of the SARRP was measured. In the 3D setup, the 3D contours of CBCT and BLT contours were registered and the 3D radial offset between the 2 centroids was calculated. Results Using the visual set up, single plane offsets of 2.2 mm +/- 1.2 mm and 2.5 mm +/- 1.5 mm were calculated between the isocenter of the vertical beam and the centroid of the bulb in unrestrained and restrained mice, respectively. After fusing the coronal 2D BL image to a corresponding coronal CBCT image, the central axis of the vertical beam was again aligned to the skin mark. The offset distances in a single plane were 2.2 mm +/- 1.2 mm and 2.4 mm +/- 1.1 mm in unrestrained and restrained mice, respectively. Finally, the offsets between the center of mass of the BL source and the CBCT glass bead after 3D fusion were 1.5 mm +/- 1 mm and 1.6 mm +/- 0.8 mm in unrestrained and restrained mice, respectively. Conclusion Restraining mice between modalities did not result in significant reduction of set up uncertainty. Similarly, use of 2D-BLI did not improve upon the visual set up method. The 3D-BLT fusion represents the best that can be achieved with off-line localization. An on-board approach with further improvement in BLT using prior information of anatomic and optical properties should be investigated to further improve localization uncertainty. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5725. doi:1538-7445.AM2012-5725

Comparison of a simple dose-guided intervention technique for prostate radiotherapy with existing anatomical image guidance methods

A simple dose-guided intervention technique for prostate radiotherapy using an isodose overlay method combined with soft-tissue-based corrective couch shifts has been proposed previously. This planning study assesses the potential clinical impact of such a correction strategy. 10 patients, each with 8-11 on-treatment CT studies (n=97), were assessed using this technique and compared with no intervention, bony anatomy intervention and soft-tissue intervention methods. Each assessment technique used a 4-mm action level for intervention. Outcomes were evaluated using measures of sensitivity, specificity and dosimetric effect, and compared across intervention techniques. Dosimetric effect was defined as the change in dosimetric coverage by the 95% isodose from the no intervention case of an evaluation construct called the verification target volume. Bony anatomy, soft tissue and dosimetric overlay-based interventions demonstrated sensitivity of 0.56, 0.73 and 1.00 and specificity of 0.64, 0.20 and 0.66, respectively. A detrimental dosimetric effect was shown in 7% of interventions for each technique, with benefit in 30%, 35% and 55% for bony anatomy, soft tissue and dosimetric overlay techniques, respectively. Used in conjunction with soft-tissue-based corrective couch shifts, the dosimetric overlay technique allows effective filtering out of dosimetrically unnecessary interventions, making it more likely that any intervention made will result in improved target volume coverage.

Initial experience and clinical comparison of two image guidance methods for SBRT treatment: 4DCT versus respiratory‐triggered imaging

For Stereotactic Body Radiation Therapy (SBRT) treatment of lung and liver, we quantified the differences between two image guidance methods: 4DCT and ExacTrac respiratory‐triggered imaging. Five different patients with five liver lesions and one lung lesion for a total of 19 SBRT delivered fractions were studied. For the 4DCT method, a manual registration process was used between the 4DCT image sets from initial simulation and treatment day to determine the required daily image‐guided corrections. We also used the ExacTrac respiratory‐triggered imaging capability to verify the target positioning, and calculated the differences in image guidance shifts between these two methods. The mean (standard deviation) of the observed differences in image‐guided shifts between 4DCT and ExacTrac respiratory‐triggered image guidance was left/right (L/R)=0.4(2.0)mm, anterior/posterior (A/P)=1.4(1.7) mm, superior/inferior (S/I)=2.2(2.0) mm, with no difference larger than 5.0 mm in any given direction for any individual case. The largest error occurred in the S/I direction, with a mean of 2.2 mm for the six lesions. This seems reasonable, because respiratory motion and the resulting imaging uncertainties are most pronounced in this S/I direction. Image guidance shifts derived from ExacTrac triggered imaging at two extreme breathing phases (i.e., full exhale vs. full inhale), agreed well (less than 2.0 mm) with each other. In summary, two very promising image guidance methods of 4DCT and ExacTrac respiratory‐triggered imaging were presented and the image guidance shifts were comparable for the patients evaluated in this study.PACS number: 87.55.ne

Comparisons of Multiple Anatomy-based Image-guidance Methods for Patient Setup before Head and Neck External-beam Radiotherapy

Comparisons of Multiple Anatomy-based Image-guidance Methods for Patient Setup before Head and Neck External-beam Radiotherapy

Automatic image guidance for prostate IMRT using low dose CBCT

Varian's On-Board Imager is a linac-integrated cone-beam CT (CBCT) system used at the authors' institution to acquire images prior to delivering each fraction of prostate intensity modulated radiotherapy. The images are used to determine a couch shift that realigns the tumor with the position obtained in the planning CT. However, this manual image-guided radiotherapy (IGRT) technique is operator dependent, time consuming, offers limited degrees of freedom, and requires significant imaging dose over the course of treatment. To overcome these problems, the authors propose two fully automatic IGRT techniques that require significantly less imaging dose. Dose is reduced by lowering the x-ray tube mA s during CBCT acquisition at the cost of increasing image noise. In "forward" IGRT, the CBCT image is automatically registered to the planning CT to obtain the necessary couch shift. The "reverse" technique offers additional degrees of freedom as it involves nonrigid registration of the planning CT to the CBCT. Both techniques were evaluated using images of an anthropomorphic phantom with simulated motion and by retrospectively analyzing data from ten prostate cancer patients. IGRT error for the phantom data at 100% relative imaging dose was 8.2 +/- 3.7, 3.5 +/- 1.2,, and 2.1 +/- 0.6 mm for setup only, forward, and reverse techniques, respectively. For patient images acquired at 100% relative imaging dose, the errors were 5.4 +/- 1.7, 5.0 +/- 1.6, 5.0 +/- 2.0, and 4.0 +/- 1.6 mm for setup only, manual forward (performed clinically), automatic forward, and reverse IGRT, respectively. Furthermore, imaging dose could be reduced to 20% without a significant loss in image guidance accuracy. The presented image guidance methods are accurate while requiring only 20% of the standard imaging dose. The combination of low dose, automation, and accuracy enables frequent corrections during treatment, possibly leading to reduced margins and improved treatment outcomes.

Investigating User Perspective on Training and Clinical Implementation of Volumetric Imaging

Purpose: Volumetric imaging (VI) is gaining momentum as a clinical tool for image guidance. The purpose of this study was to explore radiation therapists' (RTs) perception of VI training and clinical implementation. The results provide an evaluation of current training for continuous improvement, identify educational needs for the future, and chart a path for higher level evaluation of the learning activities. Methods: Sixty-five RTs who received initial training and subsequent front-end user experience with VI were contacted with an electronic posttraining questionnaire. Defined with assistance from a pilot group to encompass relevant aspects of training and VI, the survey consisted of 16 questions using a 4-point Likert scale and 1 open-ended comment box. The main sections of the survey were: demographics, current training satisfaction, user perception of competence with VI software manipulation, and assessment of future training needs for RTs. Results: Forty-five returned surveys (69%) were used for analysis. Results were examined for all participants, and then separated by subgroups for comparison with the Fisher exact test. The subgroups used were years of RT experience (<2 years, 2–5 years, 6–10 years, >10 years), and length of hands-on practice with VI (<3 months, 3–6 months, 7–9 months, >9 months). There was a consensus that training was organized (93%), comprehensive (89%), and adequate for VI clinical application (91%). Although 62% of respondents were confident with soft-tissue visualization, 95% agreed with the need for further training. Proposed cross-sectional anatomy review was seen as beneficial in 73%, though analysis with subgroups (experience with VI [ P = .042], experience as an RT [ P = .019]) showed that less experienced staff perceived a supplemental review session valuable. A total of 93% had confidence using VI for image matching; however, subgroup analysis revealed that the more experienced RTs are less confident ( P = .016). Although only 58% agreed that workflow is improved with VI, 93% felt that volumetric imaging increased accuracy of radiotherapy. Common themes for improvement of future training sessions included conducting training closer to VI unit placement, and increased hands-on use of the software complemented case studies. Conclusions: RTs felt the initial VI image training assisted them in gaining confidence in interpreting and analyzing information obtained from VI. They found this training organized, comprehensive, and adequate for their needs. Continuous training for implementation of new technology is essential to the success of image guidance methods.