Respiratory Motion Tracking Research Articles

Preliminary Report of Stereotactic Body Radiation Therapy With Respiratory Motion Tracking for Liver Tumors

Dosimetric Analysis of Gastroduodenal Toxicity by Endoscopy in Cirrhotic Patients After Radiation Therapy for Hepatocellular Carcinoma H. Yoon, D. Oh, H. Park, S. Kang, S. Park, and Y. Han; Sungkyunkwan University, Seoul, Korea, Republic of Korea, Samsung Medical Center, Seoul, Korea, Republic of Korea, Samsung Medical Center, Sungkyunkwan University, Seoul, Korea, Republic of Korea, Korea University, Seoul, Korea, Republic of Korea

Image-Guided Robotic Stereotactic Radiation Therapy with Fiducial-Free Tumor Tracking for Lung Cancer

PurposeStereotactic body radiation therapy (SBRT) for early-stage lung cancer can be achieved with several methods: respiratory gating, body frame, or real-time target and motion tracking. Two target tracking methods are currently available with the CyberKnife® System: the first one, fiducial tracking, requires the use of radio-opaque markers implanted near or inside the tumor, while the other, Xsight® Lung Tracking System, (XLTS) is fiducial-free. With XLTS, targeting is synchronized directly with target motion, which occurs due to respiration. While the former method (fiducial tracking) is well documented, the clinical relevance of the latter (tracking without fiducials) has never been well described to this date.Patients and MethodsA study was performed at our department for each patient treated for lung cancer with CyberKnife using XLTS. Selection criteria were: primary or recurring T1 or T2 stage non-small-cell lung cancer (NSCLC) with 15–60 mm tumor size. Initial staging included CT-Scan and FDG-PET.ResultsFifty-one patients not amenable to surgery were treated with XLTS. Median follow-up was 15 months (range, 5–30 months). Median tumor size was 24 mm (range, 15–60 mm). Median total dose was 60 Gy (36–60 Gy) in three fractions. Actuarial overall survival was 85.5% (95% CI = 74.5–96%) at 1 year and 79.4% (95% CI = 64–94.8%) at 2 years. Actuarial local control rate was 92% (95% CI = 84–99%) at one1 year and 86% (95% CI = 75–97%) at 2 years.ConclusionLocal control and overall survival rates were similar to previous reports that used fiducials for tumor tracking. Toxicity was lower than most studies since tumor tracking did not require fiducial implantion. This fiducial-free method for respiratory motion tracking is a valid option for the most fragile patients.

SU-E-J-158: A Prototype of a Real-Time Respiratory Motion Monitoring System Using Microsoft Kinect Sensor.

To investigate the feasibility of a low-cost respiratory motion monitoring system based on the Microsoft Xbox Kinect sensor. We improved Kinect's inherent depth resolution from 1 cm to 1 mm via a motion magnification system. Using the Kinect software development kit, we programmed the Kinect to capture depth images and determine the average depth over a thoracic region of interest, viewed almost parallel to the subject's surface. Kinect respiratory traces (average depth vs time at a rate of 30 Hz) were acquired from four volunteers and compared with those simultaneously acquired using a commercially available strain gauge respiratory gating system. The correlation coefficient (CC) between Kinect and strain gauge traces varied from 0.958 to 0.978, with a mean CC of 0.969. This strong correlation was also demonstrated by the joint probability distribution and visual inspection. This work demonstrates the feasibility of using the Kinect for respiratory motion tracking. Traces are similar to those of a clinically used strain gauge system. The Kinect-based system provides a new and economical way to monitor respiratory motion.

A real‐time respiratory motion monitoring system using KINECT: Proof of concept

The purpose of this study is to investigate the feasibility of a low-cost respiratory motion monitoring system based on the Microsoft KINECT sensor. The authors increased KINECT's inherent depth resolution from 1 cm to 1 mm via a motion magnification system. Using the KINECT software development kit, the authors programmed the KINECT to capture depth images and determine the average depth over a thoracic region of interest, viewed almost parallel to the subject's surface. KINECT respiratory traces (average depth vs time at a rate of 30 Hz) were acquired from four volunteers and compared with those simultaneously acquired using a commercially available strain gauge respiratory gating system. The correlation coefficient (CC) between KINECT and strain gauge traces varied from 0.958 to 0.978, with a mean CC of 0.969. This strong correlation was also demonstrated by the joint probability distribution and visual inspection. It is feasible to use the KINECT for respiratory motion tracking. Traces are similar to those of a clinically used strain gauge system. The KINECT-based system provides a new and economical way to monitor respiratory motion.

Multileaf collimator tracking integrated with a novel x-ray imaging system and external surrogate monitoring

We have previously developed a tumour tracking system, which adapts the aperture of a Siemens 160 MLC to electromagnetically monitored target motion. In this study, we exploit the use of a novel linac-mounted kilovoltage x-ray imaging system for MLC tracking. The unique in-line geometry of the imaging system allows the detection of target motion perpendicular to the treatment beam (i.e. the directions usually featuring steep dose gradients). We utilized the imaging system either alone or in combination with an external surrogate monitoring system. We equipped a Siemens ARTISTE linac with two flat panel detectors, one directly underneath the linac head for motion monitoring and the other underneath the patient couch for geometric tracking accuracy assessments. A programmable phantom with an embedded metal marker reproduced three patient breathing traces. For MLC tracking based on x-ray imaging alone, marker position was detected at a frame rate of 7.1 Hz. For the combined external and internal motion monitoring system, a total of only 85 x-ray images were acquired prior to or in between the delivery of ten segments of an IMRT beam. External motion was monitored with a potentiometer. A correlation model between external and internal motion was established. The real-time component of the MLC tracking procedure then relied solely on the correlation model estimations of internal motion based on the external signal. Geometric tracking accuracies were 0.6 mm (1.1 mm) and 1.8 mm (1.6 mm) in directions perpendicular and parallel to the leaf travel direction for the x-ray-only (the combined external and internal) motion monitoring system in spite of a total system latency of ∼0.62 s (∼0.51 s). Dosimetric accuracy for a highly modulated IMRT beam–assessed through radiographic film dosimetry–improved substantially when tracking was applied, but depended strongly on the respective geometric tracking accuracy. In conclusion, we have for the first time integrated MLC tracking with x-ray imaging in the in-line geometry and demonstrated highly accurate respiratory motion tracking.

Tracking latency in image-based dynamic MLC tracking with direct image access

Purpose. Target tracking is a promising method for motion compensation in radiotherapy. For image-based dynamic multileaf collimator (DMLC) tracking, latency has been shown to be the main contributor to geometrical errors in tracking of respiratory motion, specifically due to slow transfer of image data from the image acquisition system to the tracking system via image file storage on a hard disk. The purpose of the current study was to integrate direct image access with a DMLC tracking system and to quantify the tracking latency of the integrated system for both kV and MV image-based tracking. Method. A DMLC tracking system integrated with a linear accelerator was used for tracking of a motion phantom with an embedded tungsten marker. Real-time target localization was based on x-ray images acquired either with a portal imager or a kV imager mounted orthogonal to the treatment beam. Images were processed directly without intermediate disk access. Continuous portal images and system log files were stored during treatment delivery for detailed offline analysis of the tracking latency. Results. The mean tracking system latency for kV and MV image-based tracking as function of the imaging interval ΔTimage increased linearly with ΔTimage as 148 ms + 0.58 * ΔTimage (kV) and 162 ms + 1.1 * ΔTimage (MV). The latency contribution from image acquisition and image transfer for kV image-based tracking was independent on ΔTimage at 103 ± 14 ms. For MV-based tracking, it increased with ΔTimage as 124 ms + 0.44 * ΔTimage. For ΔTimage = 200 ms (5 Hz imaging), the total latency was reduced from 550 ms to 264 ms for kV image-based tracking and from 500 ms to 382 ms for MV image-based tracking as compared to the previously used indirect image transfer via image file storage on a hard disk. Conclusion. kV and MV image-based DMLC tracking was successfully integrated with direct image access. It resulted in substantial tracking latency reductions compared with image-based tracking without direct image access.

TH-E-220-05: Minimization of Imaging Dose for Real-Time Respiratory Motion Monitoring during Arc Therapy

Purpose: To develop and evaluate a methodology for using hybrid MV‐kV imaging technique for real‐time respiratory motion tracking during arc therapy with minimized extra imaging dose while maintaining high 3D targeting accuracy. Methods: In our method, at the beginning 4 seconds of a typical arc delivery for tumors in the thoracic and abdominal region, the implanted marker positions are measured continuously using stereoscopic MV‐kV imaging. At later times, only treatment‐beam cine‐MV images are acquired. The 3D time‐varying marker positions are estimated by combining the 2D projection data and the correlative relationship between the directional components of marker motion established from stereoscopic imaging, with the constraint that the position minimizing the distance to the first principal component line segment is the most likely position. A multivariate linear regression method is used to predict the marker positions 310 and 460 ms in the future. To evaluate the proposed method, computer simulations were performed using over 70 hours of thoracic and abdominal tumor motion data from 46 patients. A Gaussian noise with zero mean and 0.5 mm standard deviation was added to the projected marker positions on the imagers to simulate the systemcalibration and marker detection errors. Results: The average RMS error of the 3D position estimation was 0.76 mm. At a 310 ms latency, the average overall RMS positioning accuracy was 1.23 mm. At a 410 ms latency, the error increases to 1.46 mm. Because the kV imaging is only used for a short period of time, the extra patient dose from imaging in IGRT can be reduced for at least an order of magnitude. Conclusions: The proposed clinically‐ready hybrid MV‐kV imaging method incurs minimal imaging dose to the patient as compared with other stereoscopic imaging techniques because of an informed exploitation of “dose‐free” cine‐MV imaging without sacrificing targeting accuracy.

SU-E-T-584: The Accuracy of the Respiratory Motion Tracking with Robotic Radiosurgery System

Purpose: To evaluate the accuracy of the respiratory motion tracking system of the CyberKnife by Beam's eye view images from CCDcamera. Methods: The ball, 20.1 mm in diameter, in which gold marker was placed was used as a target. Using a dynamic motion phantom, it moved based on motion either of data sets from a sine curve or irregular patterns of respiration that came from two patients, both of which had 1 cm amplitude. Treatment planning was based on a static CT scan using standard parameters for CyberKnife treatment, and all of the beams in the plan aimed center of the ball. Beam's eye view images were recorded with a CCDcamera mounted on a linac head which was tracking the ball. The errors from displacement between the CCDcamera's central axis and center of the ball were measured by fifteen times per second, with self‐developed software. Results: In the case of the motion by the sine curve, errors were 2mm or less at 99% of the tracking time. In the case of the respiratory irregular motion, errors were 3mm or less in 99% of the tracking time. However, more than 5 mm errors were momentarily detected. Conclusions: We developed a method to measure statistically the error of the respiratory motion tracking. In this experiment, it was very small; however, larger errors were observed in irregular motion, comparing with regular motion with the same amplitude. The reason is the respiratory motion tracking system uses the algorithm based on prediction of the future target position using past pattern of motion. Thus, PTV margin may be set for each patient individually.

TU‐G‐BRC‐07: Multileaf Collimator Tracking of Respiratory Motion Using a Novel X‐Ray Monitoring System

Purpose: To demonstrate for the first time MLC tracking of respiratory motion based solely on x‐ray motion monitoring in the unique in‐line geometry. Methods: A Siemens Artiste linac was equipped with two flat‐panel imagers (FPI), one directly underneath the linac head, the other underneath the patient couch. The kV x‐ray beam pointed towards the linac head and was tilted by 5.4deg from the MV treatment beam axis, such that the two beams were spatially separated on both FPIs. A programmable phantom with an embedded metal marker reproduced a 3D lung tumor motion trace. The marker position was automatically detected in the kV images, which were acquired on the upper FPI at a frame‐rate of 7.1Hz. The marker coordinates were sent to our tumor tracking system, which adapted the aperture of a Siemens 160 MLC in real‐time. System latency was compensated through a linear regression predictor, which was trained on a 40s breathing data window. The lower FPI was used to assess both the system latency and the geometric tracking accuracy by identifying MV field and marker position. System latency was determined by tracking a sinusoidal motion trace without prediction and calculating the phase difference from least squares fits to the phantom and treatment field trajectories. Radiochromic films were used to assess dosimetric tracking accuracy. A static radiation delivery to the non‐moving target served as reference for the delivery to the moving phantom with and without tracking. Results: The total system latency was 740ms. Respiratory motion tracking yielded root mean squared deviations between phantom and MV field positions of 1.71mm (1.26mm) parallel (perpendicular) to the leaf travel direction. 2%/2mm gamma failure rates were decreased from 42% to 20%. Conclusions: We achieved accurate MLC tracking of irregular breathing motion (perpendicular to the treatment beam) based solely on x‐ray imagery.Supported by Siemens Healthcare/CR.

Report of AAPM TG 135: Quality assurance for robotic radiosurgery

The task group (TG) for quality assurance for robotic radiosurgery was formed by the American Association of Physicists in Medicine's Science Council under the direction of the Radiation Therapy Committee and the Quality Assurance (QA) Subcommittee. The task group (TG-135) had three main charges: (1) To make recommendations on a code of practice for Robotic Radiosurgery QA; (2) To make recommendations on quality assurance and dosimetric verification techniques, especially in regard to real-time respiratory motion tracking software; (3) To make recommendations on issues which require further research and development. This report provides a general functional overview of the only clinically implemented robotic radiosurgery device, the CyberKnife. This report includes sections on device components and their individual component QA recommendations, followed by a section on the QA requirements for integrated systems. Examples of checklists for daily, monthly, annual, and upgrade QA are given as guidance for medical physicists. Areas in which QA procedures are still under development are discussed.

Stereotactic Radiotherapy of Hepatocellular Carcinoma: Preliminary Results

Stereotactic radiotherapy (SRT) offers a treatment option for hepatocellular carcinoma (HCC) patients that are not eligible for surgery, embolization, chemotherapy, or radiofrequency ablation. We have evaluated the feasibility, tolerance and toxicity of SRT for 25 HCC patients who were not eligible for these other modalities. The patients (6 women and 19 men) were treated with CyberKnife stereotactic radiotherapy using respiratory motion tracking. All patients had liver cirrhosis with an Eastern Cooperative Oncology Group (ECOG) performance score of less than 2 and pre-treatment Child scores ranging from A5 to B9. A total dose of 45 Gy in three fractions of 15 Gy each was prescribed to the 80% isodose line (95% of the PTV received 45 Gy) and delivered to the target volume over 10 to 12 days. Overall the treatment was well tolerated with two Grade 3 acute toxicities and no acute Grade 4 toxicities. Late toxicity was minimal with all observed late toxicities occurring within the first six months of follow-up. Three hepatic recurrences at a distance from the target and one metastasis were observed. The actuarial 1- and 2-year local control rate was 95% (95% CI: 69-95%). At a median overall follow-up of 12,7 months (range, 1-24 months), six of the twenty-five (24%) patients have died. Overall actuarial survival at 1- and 2-years was 79% (95% CI: 52-92%) and 52% (95% CI: 19-78%), respectively. Our results suggest promising therapeutic efficacy and good clinical tolerance to CyberKnife SRT treatment for HCC patients not eligible for other treatment modalities.

Stereotactic Body Radiotherapy and Gemcitabine for Locally Advanced Pancreatic Cancer

Patients with nonmetastatic locally advanced unresectable pancreatic cancer have a dismal prognosis. Conventional concurrent chemoradiotherapy requires 6 weeks of daily treatment and can be arduous. We explored the safety and effectiveness of a 3-day course of hypofractionated stereotactic body radiotherapy (SBRT) followed by gemcitabine in this population. A total of 36 patients with nonmetastatic, locally advanced, unresectable pancreatic cancer with ≥12 months of follow-up were included. They received three fractions of 8, 10, or 12 Gy (total dose, 24-36 Gy) of SBRT according to the tumor location in relation to the stomach and duodenum, using fiducial-based respiratory motion tracking on a robotic radiosurgery system. The patients were then offered gemcitabine for 6 months or until tolerance or disease progression. With an overall median follow-up of 24 months (range, 12-33), the local control rate was 78%, the median overall survival time was 14.3 months, the median carbohydrate antigen 19-9-determined progression-free survival time was 7.9 months, and the median computed tomography-determined progression-free survival time was 9.6 months. Of the 36 patients, 28 (78%) eventually developed distant metastases. Six patients (17%) were free of progression at the last follow-up visit (range, 13-30 months) as determined by normalized tumor markers with stable computed tomography findings. Nine Grade 2 (25%) and five Grade 3 (14%) toxicities attributable to SBRT occurred. Hypofractionated SBRT can be delivered quickly and effectively in patients with nonmetastatic, locally advanced, unresectable pancreatic cancer with acceptable side effects and minimal interference with gemcitabine chemotherapy.

Dynamic Multileaf Collimator Tracking of Respiratory Target Motion Based on a Single Kilovoltage Imager During Arc Radiotherapy

To demonstrate and characterize dynamic multileaf collimator (DMLC) tracking of respiratory moving targets that are spatially localized with a single kV X-ray imager during arc radiotherapy. During delivery of an arc field (358 degrees gantry rotation, 72-sec duration, circular field shape), the three-dimensional (3D) position of a fiducial marker in a phantom was estimated in real time from fluoroscopic kV X-ray images acquired orthogonally to the treatment beam axis. A prediction algorithm was applied to account for system latency (570 ms) before the estimated marker position was used for DMLC aperture adaptation. Experiments were performed with 12 patient-measured tumor trajectories that were selected from 160 trajectories (46 patients) and reproduced by a programmable phantom. Offline, the 3D deviation of the estimated phantom position from the actual position was quantified. The two-dimensional (2D) beam-target deviation was quantified as the positional difference between the MLC aperture center and the marker in portal images acquired continuously during experiments. Simulations of imaging and treatment delivery extended the study to all 160 tumor trajectories and to arc treatments of 3-min and 5-min duration. In the experiments, the mean root-mean-square deviation was 1.8 mm for the 3D target position and 1.5 mm for the 2D aperture position. Simulations agreed with this to within 0.1 mm and resulted in mean 2D root-mean-square beam-target deviations of 1.1 mm for all 160 trajectories for all treatment durations. The deviations were mainly caused by system latency (570 ms). Single-imager DMLC tracking of respiratory target motion during arc radiotherapy was implemented, providing less than 2-mm geometric uncertainty for most trajectories.

Stereotactic Radiotherapy with Respiratory Motion Tracking for Liver Tumors: 20 Months Experience

Hypofractionated stereotactic radiotherapy (HSRT) has demonstrated good efficacy and tolerable toxicity for liver tumors, provided the volume of liver treated is restricted. Respiratory motion can necessitate wide margins to treat the lesion, which may increase the risk of radiation induced injury. Continuous tracking provides a solution that should allow for small margins, and irradiation even of relatively large lesions while sparing healthy liver and adjacent tissue. Here we present toxicity, tumor control and survival for patients with primary hepatocellular carcinomas (HCC) or liver metastases (LM) treated in the first 20 months of our program with HSRT with tumor tracking.

Clinical Accuracy of the Respiratory Tumor Tracking System of the CyberKnife: Assessment by Analysis of Log Files

To quantify the clinical accuracy of the respiratory motion tracking system of the CyberKnife treatment device. Data in log files of 44 lung cancer patients treated with tumor tracking were analyzed. Errors in the correlation model, which relates the internal target motion with the external breathing motion, were quantified. The correlation model error was compared with the geometric error obtained when no respiratory tracking was used. Errors in the prediction method were calculated by subtracting the predicted position from the actual measured position after 192.5 ms (the time lag to prediction in our current system). The prediction error was also measured for a time lag of 115 ms and a new prediction method. The mean correlation model errors were less than 0.3 mm. Standard deviations describing intrafraction variations around the whole-fraction mean error were 0.2 to 1.9 mm for cranio-caudal, 0.1 to 1.9 mm for left-right, and 0.2 to 2.5 mm for anterior-posterior directions. Without the use of respiratory tracking, these variations would have been 0.2 to 8.1 mm, 0.2 to 5.5 mm, and 0.2 to 4.4 mm. The overall mean prediction error was small (0.0 +/- 0.0 mm) for all directions. The intrafraction standard deviation ranged from 0.0 to 2.9 mm for a time delay of 192.5 ms but was halved by using the new prediction method. Analyses of the log files of real clinical cases have shown that the geometric error caused by respiratory motion is substantially reduced by the application of respiratory motion tracking.

Assessment of the Clinical Accuracy of Real-time Respiratory Motion Tracking by Analysis of Log Files

Assessment of the Clinical Accuracy of Real-time Respiratory Motion Tracking by Analysis of Log Files

The Effect of Transponder Motion on the Accuracy of the Calypso Electromagnetic Localization System

The Calypso localization system remotely detects miniature electromagnetic transponders implanted in a patient. The system is capable of continuously measuring the position of a treatment site during radiotherapy. If the site is moving during respiration then the system can be used for dynamic tracking of the target. With this application in mind we have made measurements to see if there is any change in localization accuracy due to transponder position or motion. Three localization transponders were mounted on a remote-controlled turntable that could move the transponders along a circular trajectory at speeds up to 3 cm/sec. A stationary calibration established the coordinates of six points on each transponder's circular path. We then compared position measurements taken while the transponders were in motion at a constant speed to the stationary coordinates. To synchronize the position of the moving transponders to a known point on the circular path we injected an RF noise pulse into the Calypso readout antenna when the turntable passed 0°. This produced outliers on the arc of moving transponder positions that could be used to compare the transponder positions in the direction of motion to the calibrated stationary positions. The stationary localization uncertainty varied from 0.02 to 0.06 cm per axis in the (x,y) plane, which is consistent with the observations of other researchers. We detected a small systematic trend in the stationary uncertainty as a function of transponder position along an arc 11 cm long. Lung tumors do not move more than about 3 cm in the most extreme cases. Therefore the Calypso system will have less than 0.02 cm systematic change in localization accuracy over the full range of tumor position. There was no statistically significant change in the transponder positions in either the radial or tangential direction when the transponders were in motion. If the Calypso system is used for real-time respiratory motion tracking, then tracking accuracy will be unaffected by transponder motion, at least for the velocity and position range that will be encountered in clinical applications. If the transponder is moving, its reported location corresponds precisely to its position at the midpoint of the readout interval, regardless of speed.

PET/CT Target Delineation with Respiratory Motion Tracking for Early Stage Lung Cancer Radiosurgery

PET/CT Target Delineation with Respiratory Motion Tracking for Early Stage Lung Cancer Radiosurgery

Robust real-time 3D respiratory motion detection using time-of-flight cameras

PurposeRespiratory motion of the patient during data acquisition causes artifacts in the field of emission or computed tomography. Respiratory gating allows to track and correct these artifacts.Materials and methodsIn this paper, we present a system that uses the fairly new and off-the-shelf time-of-flight (ToF) technology to compute a dense estimate of the three-dimensional respiratory motion of a patient. The work is characterized by three key contributions. The first is the employment of ToF sensors. Using ToF sensors, it is feasible to acquire a dense 3D surface model of the chest and abdomen of the patient with more than 15 frames per second. The second contribution is an algorithm to derive a surface representation which enables the estimation of the 3D respiratory motion of the patient, which is sufficient to compute 1D breathing signals for scalable specific regions of interest like chest and abdomen. The proposed data-driven algorithm models the chest and abdomen three-dimensionally by fitting distinct planes to different regions of the torso of the patient. The third contribution is the possibility to derive a sub-millimeter accurate 1D respiratory motion signal by observing the displacement of each plane.ResultsOur ToF modeling approach enables marker less, real-time, 3D tracking of patient respiratory motion with an accuracy of 0.1 mm.ConclusionThus, our approach provides 1D breathing signals for scalable anatomical regions of interest with sufficient accuracy for artifact reduction in SPECT or X-ray angiography.

SU‐GG‐T‐507: 4D Planning: Dose Calculation That Accounts for Moving Beams and Tissue Deformation

Purpose: To evaluate the ability of 4D Treatment Optimization and Planning, which is a recently available feature in the MultiPlan® Treatment Planning System for 4D treatment planning for motion tracking with the CyberKnife® Robotic Radiosurgery System, to calculate a dose distribution that takes into account both beam movement due to respiratory motion and soft tissue deformation. Method and Materials: A phantom was developed for 4D planning validation, containing a target that exhibits periodic motion driven by a motor, and a critical structure adjacent to the target. A 4D CT scan of the phantom in motion was obtained, and a treatment plan created on this 4D CT scan using MultiPlan with the 4D Planning module. The target has fiducials embedded in it, and Synchrony® Respiratory Motion Tracking System was used so that the treatment beams followed the target motion. Radiochromic film was placed in the critical structure and the treatment plan was delivered. The film dose after treatment was compared with that calculated by MultiPlan using both the static dose calculation (3D dose) and that calculated using the 4D Planning module. The 4D Planning module uses deformable registration and information about beam movement to calculate a dose distribution that takes into account both target movement and tissue deformation during treatment (4D dose). Results: For the 3D dose in the coronal film, 64.4% of pixels had a disagreement of 3% or less between measured and predicted dose; for the 4D dose distribution, 97.6% of pixels had a disagreement of 3% or less. Using a Gamma function with a passing criterion of 5% dose difference or 3mm distance to agreement, 94.9% of pixels pass for the 3D dose and 100.0% of pixels pass for 4D dose. Conclusion: The 4D Planning module accurately calculated dose in this phantom test for a moving target.