bluuebunny/crossref_metadata_2025 huggingface dataset:
SU‐G‐IeP4‐07: Feasibility of Low Dose 18FDG PET in Pediatric Oncology Patients
Authors: Zhang J , Binzel K , Hall NC , Natwa M , Knopp MI , Knopp MV
Published: July 2016

Purpose:

To evaluate and demonstrate the feasibility of low dose FDG PET in pediatric oncology patients using virtual dose reduction as well as true patients PET/CT scans.

Methods:

Wholebody 18F‐FDG PET/CT of 39 clinical pediatric patients (0.16±0.06MBq/kg) were scanned on a Gemini TF 64 system at 75±5 min post FDG injection using 3min/bed. Based on the 180s/bed listmode PET data, subsets of total counts in 120s, 90s, 60s, 30s and 15s per bed position were extracted for PET reconstruction to simulate lower dose PET at 2/3th, 1/2th, 1/3th, 1/6th and 1/12th dose levels. PET/CT scans of Jaszczak PET phantom with 6 hot hollow spheres varying with sizes and contrast ratios were performed (real PET versus simulated PET) to validate the methodology of virtual dose PET simulation. Region of interests (ROIs) were placed on lesions and normal anatomical tissues with quantitative and qualitative assessment performed. Significant lower FDG dose PET/CT of 5 research adolescents were scanned to validate the proposal and low dose PET feasibility.

Results:

Although all lesions are visible on the 1/12th dose PET, overall PET image quality appears to be influenced in a multi‐factorial way. 30%–60% dose reduction from current standard of care FDG PET is recommended to maintain equivalent quality and PET quantification. An optimized BMI‐based FDG administration is recommended (from 1.1±0.5 mCi for BMI < 18.5 to 4.8±1.5 mCi for BMI > 30). A linear lowest “Dose‐BMI” relationship is given. SUVs from 1/12th to full dose PETs were identified as consistent (R2 = 1.08, 0.99, 1.01, 1.00 and 0.98). No significant variances of count density, SUV and SNR were found across certain dose ranges (p<0.01).

Conclusion:

Pediatric PET/CT can be performed using current time‐of‐flight systems at substantially lower PET doses (30–60%) than the standard of care PET/CT without compromising qualitative and quantitative image quality in clinical.
SU‐G‐IeP4‐08: Initial Investigations of Up‐Converting Nanoparticles (UCNP) for 3D Tissue Imaging in Optical‐ECT
Authors: Yoon S , Langloss B , Boss M , Birer S , Dewhirst M , Oldham M
Published: July 2016

Purpose:

Near‐IR absorptive up‐converting nanoparticles (UCNPs) is a novel contrast for optical‐ECT that allows auto‐fluorescence‐free 3D imaging of labeled cells in a matrix of large (∼1cm3) unsectioned normal tissue. This has the potential to image small metastases or dormant cells that is difficult with down‐converting fluorescing dyes due to auto‐fluorescence. The feasibility of imaging UCNP in agarose phantoms and a mouse lung is demonstrated, aided by a 3D‐printed optical‐ECT stage designed to excite UCNP in a mouse lung.

Methods:

The UCNP, NaYF4:Yb/Er (20/2%), studied in this work up‐converts 980nm light to visible light peaking sharply at ∼540nm. To characterize the UCNP emission as a function of UCNP concentration, cylindrical 2.5%wt agarose phantoms infused with UCNP at concentrations of 25µg/mL and 50µg/mL were exposed to 1.5W 980nm laser coupled to an optical fiber. The fiber was held stably at 1cm above the stage via a custom 3D‐printed stage. An optically cleared lung harvested from a BALBc mice was then injected with 100µL of 1mg/mL UCNP solution ex vivo. Tomographic imaging of the UCNP emission in lung was performed.

Results:

The laser beam tract is visualized within the agarose phantom. A line profile of UCNP emission at 25µg/mL versus 50µg/mL shows that increasing the UCNP concentration increases emission count. UCNPs injected into a cleared mouse lung disperse throughout the respiratory tract, allowing for visualization and 3D reconstruction. Excitation before and after UCNP injection shows the tissue exhibits no auto‐fluorescence at 980nm, allowing clear view of the UCNP without any obscuring features such as conventional down‐converting fluorescent tags.

Conclusion:

We confirm that up‐conversion in tissue circumvents completely tissue auto‐fluorescence, which allowed background‐free 3D reconstruction of the UCNP distribution. We also confirm that raising the UCNP concentration increases emission and that UCNPs are retained in agarose samples during the optical clearing process.
SU‐G‐IeP4‐15: Ultrasound Imaging of Absorbable Inferior Vena Cava Filters for Proper Placement
Authors: Mitcham T , Bouchard R , Melancon A , Eggers M , Melancon M
Published: July 2016

Purpose:

Inferior vena cava filters (IVCFs) are used in patients with a high risk of pulmonary embolism in situations when the use of blood thinning drugs would be inappropriate. These filters are implanted under x‐ray guidance; however, this provides a dose of ionizing radiation to both patient and physician. B‐mode ultrasound (US) imaging allows for localization of certain implanted devices without radiation dose concerns. The goal of this study was to investigate the feasibility of imaging the placement of absorbable IVCFs using US imaging to alleviate the dosage concern inherent to fluoroscopy.

Methods:

A phantom was constructed to mimic a human IVC using tissue‐mimicking material with 0.5 dB/cm/MHz acoustic attenuation, while agar inclusions were used to model acoustic mismatch at the venous interface. Absorbable IVCF's were imaged at 15 cm depth using B‐mode US at 2, 3, 5, and 7 MHz transmit frequencies. Then, to determine temporal stability, the IVCF was left in the phantom for 10 weeks; during this time, the IVCF was imaged using the same techniques as above, while the integrity of the filter was analyzed by inspecting for fiber discontinuities.

Results:

Visualization of the inferior vena cava filter was possible at 5, 7.5, and 15 cm depth at US central frequencies of 2, 3, 5, and 7 MHz. Imaging the IVCF at 5 MHz yielded the clearest images while maintaining acceptable spatial resolution for identifying the IVCF's, while lower frequencies provided noticeably worse image quality. No obvious degradation was observed over the course of the 10 weeks in a static phantom environment.

Conclusion:

Biodegradable IVCF localization was possible up to 15 cm in depth using conventional B‐mode US in a tissue‐mimicking phantom. This leads to the potential for using B‐mode US to guide the placement of the IVCF upon deployment by the interventional radiologist.

Mitch Eggers is an owner of Adient Medical Technologies. There are no other conflicts of interest to disclose.
SU‐G‐JeP4‐02: An Investigation of Respiratory Surrogate Motion Data Requirements for Multiple‐Step Ahead Prediction
Authors: Zawisza I , Ren L , Yin F
Published: July 2016

Purpose:

Respiratory‐gated radiotherapy and dynamic tracking employ real‐time imaging and surrogate motion‐monitoring methods with tumor motion prediction in advance of real‐time. This study investigated respiratory motion data length on prediction accuracy of tumor motion.

Methods:

Predictions generated from the algorithm are validated against a one‐dimensional surrogate signal of amplitude versus time. Prediction consists of three major components: extracting top‐ranked subcomponents from training data matching the last respiratory cycle; calculating weighting factors from best‐matched subcomponents; fusing data proceeding best‐matched subcomponents with respective weighting factors to form predictions. Predictions for one respiratory cycle (∼3‐6seconds) were assessed using 351 patient data from the respiratory management device. Performance was evaluated for correlation coefficient and root mean square error (RMSE) between prediction and final respiratory cycle.

Results:

Respiratory prediction results fell into two classes, where best predictions for 70 cycles or less performed using relative prediction and greater than 70 cycles are predicted similarly using relative and derivative relative. For 70 respiratory cycles or less, the average correlation between prediction and final respiratory cycle was 0.9999±0.0001, 0.9999±0.0001, 0.9988±0.0003, 0.9985±0.0023, and 0.9981±0.0023 with RMSE values of 0.0091±0.0030, 0.0091±0.0030, 0.0305±0.0051, 0.0299±0.0259, and 0.0299±0.0259 for equal, relative, pattern, derivative equal and derivative relative weighting methods, respectively. Respectively, the total best prediction for each method was 37, 65, 20, 22, and 22. For data with greater than 70 cycles average correlation was 0.9999±0.0001, 0.9999±0.0001, 0.9988±0.0004, 0.9988±0.0020, and 0.9988±0.0020 with RMSE values of 0.0081±0.0031, 0.0082±0.0033, 0.0306±0.0056, 0.0218±0.0222, and 0.0218±0.0222 for equal, relative, pattern, derivative equal and derivative relative weighting methods, respectively. Respectively, the total best prediction for each method was 24, 44, 42, 30, and 45.

Conclusion:

The prediction algorithms are effective in estimating surrogate motion in advance. These results indicate an advantage in using relative prediction for shorter data and either relative or derivative relative prediction for longer data.
SU‐G‐JeP4‐06: Evaluation of Interfractional and Intrafractional Tumor Motion in Stereotactic Liver Radiotherapy, Based On Four‐Dimensional Cone‐Beam Computed Tomography Using Fiducial Markers
Authors: Shimohigashi Y , Araki F , Toya R , Maruyama M , Nakaguchi Y
Published: July 2016

Purpose:

The purpose of this study was to evaluate the interfractional and intrafractional motion of liver tumors in stereotactic body radiation therapy (SBRT), based on four‐dimensional cone‐beam computed tomography using fiducial markers. (4D‐CBCT).

Methods:

Seven patients with liver tumors were treated by SBRT with abdominal compression (AC) in five fractions with image guidance based on 4D‐CBCT. The 4D‐CBCT studies were performed to determine the individualized internal margin for the planning simulation. The interfractional and intrafractional changes of liver tumor motion for all patients was measured, based on the planning simulation 4D‐CBCT, pre‐SBRT 4D‐CBCT, and post‐SBRT 4D‐CBCT. The interfractional motion change was calculated from the difference in liver tumor amplitude on pre‐SBRT 4D‐CBCT relative to that of the planning simulation 4D‐CBCT for each fraction. The intrafractional motion change was calculated from the difference between the liver tumor amplitudes of the pre‐ and post‐SBRT 4D‐CBCT for each fraction. Significant interfractional and intrafractional changes in liver tumor motion were defined as a change ≥3 mm. Statistical analysis was performed using the Pearson correlation.

Results:

The values of the mean amplitude of liver tumor, as indicated by planning simulation 4D‐CBCT, were 1.6 ± 0.8 mm, 1.6 ± 0.9 mm, and 4.9 ± 2.2 mm in the left‐right (LR), anterior‐posterior (AP), and superior‐inferior (SI) directions, respectively. Pearson correlation coefficients between the liver tumor amplitudes, based on planning simulation 4D‐CBCT, and pre‐SBRT 4D‐CBCT during fraction treatment in the LR, AP, and SI directions were 0.6, 0.7, and 0.8, respectively. Interfractional and intrafractional motion changes of ≥3 mm occurred in 23% and 3% of treatment fractions, respectively.

Conclusion:

The interfractional and intrafractional changes of liver tumor motion were small in most patients who received liver SBRT with AC. In addition, planning simulation 4D‐CBCT was useful for representing liver tumor movement in patients undergoing SBRT.

This work was supported by JSPS KAKENHI Grant Number 26861004.
SU‐G‐JeP4‐09: Impact of Interfractional Motion On Hypofractionated Pencil Beam Scanning Proton Therapy for Prostate Cancer
Authors: Moteabbed M , Trofimov A , Sharp G , Wang Y , Zietman A , Efstathiou J , Lu H
Published: July 2016

Purpose:

To investigate the impact of anatomy/setup variations on standard vs. hypofractionated anterolateral pencil beam scanning (PBS) proton therapy for prostate cancer.

Methods:

Six prostate cancer patients treated with double‐scattering proton therapy, who underwent weekly verification CT scans were selected. Implanted fiducials were used for localization, and endorectal balloons for immobilization. New PBS plans using combination of lateral and anterior‐oblique (AO) (±35 deg) beams were created. AO beams were added to spare the femoral heads during hypofractionation. Lateral beams delivered 50.4 Gy(RBE) to prostate plus 5‐15mm of seminal vesicles and AO beams 28.8 Gy(RBE) to prostate, in 44 fractions. PTV was laterally expanded by 2.5% to account for range uncertainty. No range margins were applied for AO beams, assuming delivery with in‐vivo range verification. Field‐specific apertures with 1.2cm margin were used. Spot size was ∼9.5mm sigma for 172MeV @isocenter in air. Plans were optimized as single‐field‐uniform‐dose with ∼5% maximum non‐uniformity. The planned dose was recomputed on each weekly CT after aligning the fiducials with the simulation CT, scaled and accumulated via deformable image registration. Hypofractionated treatments with 12 and 5 fractions were considered. Equivalent doses were calculated for prostate (α/β= 1.5Gy), bladder and rectum (α/β= 3Gy).

Results:

The biological equivalent prostate dose was 86.2 and 92.9 Gyeq for the hypofractionation scenarios at 4.32 and 7.35 Gy/fx, respectively. The equivalent prostate D98 was degraded by on average 2.7 Gyeq for standard, and 3.1 and 4.0 Gyeq for the hypofractionated plans after accumulation. Differences between accumulated and planned Dmean/D2/EUD were generally reduced when reducing the number of fractions for bladder and rectum. The average Dmean/D2/EUD differences over all patients and organs‐at‐risk were 0.74/4.0/9.23, 0.49/3.64/5.51, 0.37/3.21/3.49 Gyeq for 44, 12 and 5 fractions.

Conclusion:

Hypofractionation makes proton therapy of prostate more susceptible to interfractional motion‐induced target dose degradation compared to the standard fractionation.
SU‐G‐JeP4‐10: Measurement of Prostate Motion Trajectories During Prostate SBRT Boost Treatments with a Rectafix
Authors: Legge K , Nguyen D , Ng J , Wilton L , Booth J , Keall P , Martin J , O'Connor D J , Greer P
Published: July 2016

Purpose:

To determine prostate motion during SBRT boost treatments with a Rectafix rectal sparing device in place using kV imaging during treatment.

Methods:

Patients each had three gold fiducial markers inserted into the prostate and received two VMAT boost fractions of 9.5–10 Gy under the PROMETHEUS clinical trial protocol with a Rectafix rectal retractor in place. Two‐dimensional kilovoltage images of fiducial markers were acquired continuously during delivery. Three patients were treated on a Varian Clinac iX linear accelerator (6X, 600 MU/min), where kV images were acquired at 5 Hz during treatment. Seven patients were treated on a Varian Truebeam linear accelerator (10XFFF, 2400 MU/min) where kV images were acquired every 3 seconds. Images were processed off‐line using the Kilovoltage Intrafraction Monitoring (KIM) software after treatment. KIM determines prostate position in three dimensions from 2D kV projections using a probability density model and a pre‐treatment kV arc. The 3D displacement of the prostate was quantified as a function of time throughout each fraction.

Results:

From all fractions analyzed, it was found that the prostate had moved less than 1 mm in any direction from its initial position 84.6% of the time. The prostate was between 1 and 2 mm from its initial position 14.2% of the time, between 2 and 3 mm of its initial position 0.8% of the time and was greater than 3 mm from its initial position only 0.4% of the time.

Conclusion:

The amount of prostate motion observed during prostate SBRT boost treatments with a Rectafix device in place was minimal and lower than that observed in non‐Rectafix studies. The Rectafix device reduces rectal dose as well as immobilizing the prostate. Kimberley Legge is the recipient of an Australian Postgraduate Award.
SU‐G‐JeP4‐12: Real‐Time Organ Motion Monitoring Using Ultrasound and KV Fluoroscopy During Lung SBRT Delivery
Authors: Omari E , Tai A , Cooper D , Lachaine M , Li X
Published: July 2016

Purpose:

Real‐time ultrasound monitoring during SBRT is advantageous in understanding and identifying motion irregularities which may cause geometric misses. In this work, we propose to utilize real‐time ultrasound to track the diaphragm in conjunction with periodical kV fluoroscopy to monitor motion of tumor or landmarks during SBRT delivery.

Methods:

Transabdominal Ultrasound (TAUS) b‐mode images were collected from 10 healthy volunteers using the Clarity Autoscan System (Elekta). The autoscan transducer, which has a center frequency of 5 MHz, was utilized for the scans. The acquired images were contoured using the Clarity Automatic Fusion and Contouring workstation software. Monitoring sessions of 5 minute length were observed and recorded. The position correlation between tumor and diaphragm could be established with periodic kV fluoroscopy periodically acquired during treatment with Elekta XVI. We acquired data using a tissue mimicking ultrasound phantom with embedded spheres placed on a motion stand using ultrasound and kV Fluoroscopy. MIM software was utilized for image fusion. Correlation of diaphragm and target motion was also validated using 4D‐MRI and 4D‐CBCT.

Results:

The diaphragm was visualized as a hyperechoic region on the TAUS b‐mode images. Volunteer set‐up can be adjusted such that TAUS probe will not interfere with treatment beams. A segment of the diaphragm was contoured and selected as our tracking structure. Successful monitoring sessions of the diaphragm were recorded. For some volunteers, diaphragm motion over 2 times larger than the initial motion has been observed during tracking. For the phantom study, we were able to register the 2D kV Fluoroscopy with the US images for position comparison.

Conclusion:

We demonstrated the feasibility of tracking the diaphragm using real‐time ultrasound. Real‐time tracking can help in identifying such irregularities in the respiratory motion which is correlated to tumor motion. We also showed the feasibility of acquiring 2D KV Fluoroscopy and registering the images with Ultrasound.
SU‐G‐JeP4‐14: Assessment of Inter‐ and Intra‐Fractional Motion for Extremity Soft Tissue Sarcoma Patients by Using In‐House Real‐Time Optical Image‐Based Monitoring System
Authors: Kim H , Kim I , Ye S
Published: July 2016

Purpose:

This study aimed to assess inter‐ and intra‐fractional motion for extremity Soft Tissue Sarcoma (STS) patients, by using in‐house real‐time optical image‐based monitoring system (ROIMS) with infra‐red (IR) external markers.

Methods:

Inter‐ and intra‐fractional motions for five extremity (1 upper, 4 lower) STS patients received postoperative 3D conformal radiotherapy (3D‐CRT) were measured by registering the image acquired by ROIMS with the planning CT image (REG_ROIMS). To compare with the X‐ray image‐based monitoring, pre‐ and post‐treatment cone beam computed tomography (CBCT) scans were performed once per week and registered with planning CT image as well (REG_CBCT). If the CBCT scan is not feasible due to the large couch shift, AP and LR on‐board imager (OBI) images were acquired. The comparison was done by calculating mutual information (MI) of those registered images.

Results:

The standard deviation (SD) of the inter‐fractional motion was 2.6 mm LR, 2.8 mm SI, and 2.0 mm AP, and the SD of the intra‐fractional motion was 1.4 mm, 2.1 mm, and 1.3 mm in each axis, respectively. The SD of rotational inter‐fractional motion was 0.6° pitch, 0.9° yaw, and 0.8° roll and the SD of rotational intra‐fractional motion was 0.4° pitch, 0.9° yaw, and 0.7° roll. The derived averaged MI values were 0.83, 0.92 for REG_CBCT without rotation and REG_ROIMS with rotation, respectively.

Conclusion:

The in‐house real‐time optical image‐based monitoring system was implemented clinically and confirmed the feasibility to assess inter‐ and intra‐fractional motion for extremity STS patients while the daily basis and real‐time CBCT scan is not feasible in clinic.
SU‐G‐TeP4‐02: A Method for Evaluating the Direct Impact of Failed IMRT QAs On Patient Dose
Authors: Geneser S , Butkus M
Published: July 2016

Purpose:

We developed a method to calculate patient doses corresponding to IMRT QA measurements in order to determine and assess the actual dose delivered for plans with failed (or borderline) IMRT QA. This work demonstrates the feasibility of automatically computing delivered patient dose from portal dosimetry measurements in the Varian TPS system, which would provide a valuable and clinically viable IMRT QA tool for physicists and physicians.

Methods:

IMRT QA fluences were measured using portal dosimetry, processed using in‐house matlab software, and imported back into Eclipse to calculate dose on the planning CT. To validate the proposed workflow, the Eclipse calculated portal dose for a 5‐field sliding window prostate boost plan was processed as described above. The resulting dose was compared to the planned dose and found to be within 0.5 Gy. Two IMRT QA results for the prostate boost plan (one that failed and one that passed) were processed and the resulting patient doses were evaluated.

Results:

The max dose difference between IMRT QA #1 and the original planned and approved dose is 4.5 Gy, while the difference between the planned and IMRT QA #2 dose is 4.0 Gy. The inferior portion of the PTV is slightly underdosed in both plans, and the superior portion is slightly overdosed. The patient dose resulting from IMRT QA #1 and #2 differs by only 0.5 Gy. With this new information, it may be argued that the evaluated plan alteration to obtain passing gamma analysis produced clinically irrelevant differences.

Conclusion:

Evaluation of the delivered QA dose on the planning CT provides valuable information about the clinical relevance of failed or borderline IMRT QAs. This particular workflow demonstrates the feasibility of pushing the measured IMRT QA portal dosimetry results directly back onto the patient planning CT within the Varian system.
SU‐G‐TeP4‐09: Development of a Plan Data Aggregator for Time Efficient Physics Second‐Checks of Machine Parameters for External Beam Treatment Plans
Authors: Belley M , Schmidt M , Knutson N , Price M
Published: July 2016

Purpose:

Physics second‐checks for external beam radiation therapy are performed, in‐part, to verify that the machine parameters in the Record‐and‐Verify (R&V) system that will ultimately be sent to the LINAC exactly match the values initially calculated by the Treatment Planning System (TPS). While performing the second‐check, a large portion of the physicists’ time is spent navigating and arranging display windows to locate and compare the relevant numerical values (MLC position, collimator rotation, field size, MU, etc.). Here, we describe the development of a software tool that guides the physicist by aggregating and succinctly displaying machine parameter data relevant to the physics second‐check process.

Methods:

A data retrieval software tool was developed using Python to aggregate data and generate a list of machine parameters that are commonly verified during the physics second‐check process. This software tool imported values from (i) the TPS RT Plan DICOM file and (ii) the MOSAIQ (R&V) Structured Query Language (SQL) database. The machine parameters aggregated for this study included: MLC positions, X&Y jaw positions, collimator rotation, gantry rotation, MU, dose rate, wedges and accessories, cumulative dose, energy, machine name, couch angle, and more.

Results:

A GUI interface was developed to generate a side‐by‐side display of the aggregated machine parameter values for each field, and presented to the physicist for direct visual comparison. This software tool was tested for 3D conformal, static IMRT, sliding window IMRT, and VMAT treatment plans.

Conclusion:

This software tool facilitated the data collection process needed in order for the physicist to conduct a second‐check, thus yielding an optimized second‐check workflow that was both more user friendly and time‐efficient. Utilizing this software tool, the physicist was able to spend less time searching through the TPS PDF plan document and the R&V system and focus the second‐check efforts on assessing the patient‐specific plan‐quality.
MO‐A‐BRC‐00: TG167: Clinical Recommendations for Innovative Brachytherapy Devices and Applicators
Authors: Nath Ravinder
Published: July 2016

Although a multicenter, Phase III, prospective, randomized trial is the gold standard for evidence‐based medicine, it is rarely used to evaluate innovative radiotherapy devices because of many practical and ethical reasons. It is usually sufficient to compare the dose distributions and dose rates for determining equivalence of the innovative device to an existing one. Thus, quantitative evaluation of the dosimetric characteristics of an innovative brachytherapy device or application is a critical part in which physicists are actively involved. The physicist's role, along with physician colleagues, in this process is highlighted for innovative products or applications and includes evaluation of 1) dosimetric considerations for clinical implementation (including calibrations, dose calculations, and radiobiological aspects) to comply with existing societal dosimetric prerequisites for sources in routine clinical use, 2) risks and benefits from regulatory and safety perspectives, and 3) resource assessment and preparedness. Further, calibration methods should be traceable to a primary standards dosimetry laboratory such as NIST in the U.S. or to other primary standards dosimetry laboratory located elsewhere. Clinical users should follow standards as approved by their country's regulatory agencies that approved such a brachytherapy device. Integration of this system into the medical source calibration infrastructure of secondary standard dosimetry laboratories such as the ADCLs is encouraged before a source is introduced into widespread routine clinical use. The AAPM and GEC‐ESTRO have developed guidelines for the safe and consistent application of brachytherapy using innovative brachytherapy devices and applications. The current report covers regulatory approvals, calibration, dose calculations, radiobiological issues, and overall safety concerns that should be addressed during the commissioning stage preceding clinical use. These guidelines are based on review of requirements of the U.S. NRC, FDA, Department of Transportation, International Electrotechnical Commission Medical Electrical Equipment Standard 60601, European Commission for CE Marking, and institutional review boards and radiation safety committees.

Learning Objectives:

Understand the necessary dosimetric considerations for clinical implementation (including calibrations, dose calculations, and radiobiological aspects) to comply with existing societal dosimetric prerequisites for sources in routine clinical use.

Evaluate risks and benefits from regulatory and safety perspectives.

Identify necessary resources and create a plan for clinical introduction of innovative brachytherapy device or applications.

Consultant for Theragenics Corp.; R. Nath, Consultant to Theragenics Corp.
MO‐AB‐BRA‐03: Development of Novel Real Time in Vivo EPID Treatment Verification for Brachytherapy
Authors: Fonseca G , Podesta M , Reniers B , Verhaegen F
Published: July 2016

Purpose:

High Dose Rate (HDR) brachytherapy treatments are employed worldwide to treat a wide variety of cancers. However, in vivo dose verification remains a challenge with no commercial dosimetry system available to verify the treatment dose delivered to the patient. We propose a novel dosimetry system that couples an independent Monte Carlo (MC) simulation platform and an amorphous silicon Electronic Portal Imaging Device (EPID) to provide real time treatment verification.

Methods:

MC calculations predict the EPID response to the photon fluence emitted by the HDR source by simulating the patient, the source dwell positions and times, and treatment complexities such as tissue compositions/densities and different applicators. Simulated results are then compared against EPID measurements acquired with ∼0.14s time resolution which allows dose measurements for each dwell position. The EPID has been calibrated using an Ir‐192 HDR source and experiments were performed using different phantoms, including tissue equivalent materials (PMMA, lung and bone). A source positioning accuracy of 0.2 mm, without including the afterloader uncertainty, was ensured using a robotic arm moving the source.

Results:

An EPID can acquire 3D Cartesian source positions and its response varies significantly due to differences in the material composition/density of the irradiated object, allowing detection of changes in patient geometry. The panel time resolution allows dose rate and dwell time measurements. Moreover, predicted EPID images obtained from clinical treatment plans provide anatomical information that can be related to the patient anatomy, mostly bone and air cavities, localizing the source inside of the patient using its anatomy as reference.

Conclusion:

Results obtained show the feasibility of the proposed dose verification system that is capable to verify all the brachytherapy treatment steps in real time providing data about treatment delivery quality and also applicator/structure motion during or between treatments.
MO‐B‐BRC‐03: CT‐Based Prostate HDR
Authors: Zoberi J.
Published: July 2016

Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra‐ or post‐operative setting. During intra‐operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra‐operative prostate HDR is U/S. Alternatively, in the post‐operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations.

Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting.

Learning Objectives:

Review prostate HDR techniques based on the imaging modality

Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy

Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions
MO‐B‐BRC‐04: MRI‐Based Prostate HDR
Authors: Mourtada F.
Published: July 2016

Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra‐ or post‐operative setting. During intra‐operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra‐operative prostate HDR is U/S. Alternatively, in the post‐operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations.

Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting.

Learning Objectives:

Review prostate HDR techniques based on the imaging modality

Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy

Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions
MO‐A‐207B‐01: Radiomics: Segmentation & Feature Extraction Techniques
Authors: Veeraraghavan H.
Published: July 2016

Image segmentation is one of the core problems for applying radiomics‐based analysis to images. However, achieving repeatable and accurate segmentations for large datasets is challenging. The choice of segmentation method, the metrics used to evaluate the quality of such segmentations all depend on the specific clinical problem. This course will introduce three approaches, namely, fully automatic, interactive, and semi‐automatic methods for generating segmentations. The pros and cons of each approach and when to choose a specific method will be discussed. Evaluation and assessment of the quality of a segmentation method is essential before it can be deployed for high‐throughput analysis such as radiomics. This course will present some of the metrics that can be used for assessing quality of segmentations and highlight their advantages and deficiencies.

Another important issue with respect to generating high quality segmentations and ultimately extracting robust radiomics features is image pre‐processing. A few pre‐processing techniques that can be used to improve the robustness of the analysis for MR and CT images will be presented.

Learning Objectives:

Understand the difference and applicability of various segmentation methods.

Understand how pre‐processing can be used to improve the robustness of feature extraction and segmentation

Understand some basics of evaluating the quality of segmentations and the relevance of such metrics for clinical problems.
MO‐B‐BRC‐02: Ultrasound Based Prostate HDR
Authors: Chang Z.
Published: July 2016

Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra‐ or post‐operative setting. During intra‐operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra‐operative prostate HDR is U/S. Alternatively, in the post‐operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations.

Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting.

Learning Objectives:

Review prostate HDR techniques based on the imaging modality

Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy

Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions
MO‐B‐207B‐00: Harmonization & Robustness in Radiomics
Authors: Court Laurence Edward
Published: July 2016

Feature extraction for radiomics studies typically comprises the following stages: Imaging, segmentation, image processing, and feature extraction. Each of these stages has associated uncertainties that can affect the quality of a radiomics model created using the resulting image features. For example, the imaging device manufacturer and model have been shown to impact the values of image features, as have pixel size and imaging protocol parameters. Image processing, such as low‐pass filtering to reduce noise, also changes calculated image features and should be designed to optimize the information content of the resulting features. The details of certain feature algorithms, such as co‐occurrence matrix bin sizes, are also important, and should be optimized for specific radiomics tasks. The volume of the region of interest should be considered as image features can be related to volume and can give unanticipated results when the volumes are too small. In this session we will describe approaches to quantify the variabilities in radiomics studies, including the most recent results quantifying these variabilities for CT, MRI and PET imaging. We will discuss methods to optimize image processing and feature extraction in order to maximize the information content of the image features. Finally, we will describe work to harmonize imaging protocols and feature calculations to help minimize uncertainties in radiomics studies.

Learning Objectives:

At the end of this session, participants will be able to:

Identify the sources of uncertainty in radiomics studies (CT, PET, and MRI imaging)

Describe methods for quantifying the magnitude of uncertainties

Describe approaches for mitigating the effects of the uncertainties on radiomics models

Funding from NIH, CPRIT, Varian, Elekta; L. Court, NCI, CPRIT, Varian, Elekta
MO‐C‐BRB‐02: The Physicists’ Leadership Role in Academic Radiology: The Chair's Perspective
Authors: Arenson R.
Published: July 2016

With the profound changes currently occurring in medicine, the role of the medical physicist cannot stagnate, but must evolve to meet the challenges and opportunities that are presented. Medical physicists must understand these changes and establish themselves not only as relevant but as leaders in this new environment. We must increase our presence in clinical settings such as tumor boards, patient rounds, and the development of new diagnosis, imaging, and treatment techniques. By establishing ourselves as competent scientists, we can and must participate in the development of technologies through research, teaching, and clinical implementation. As medical physicists we must define our roles and value to our physician colleagues, patients, referring physicians, and senior administrators. We cannot afford to be viewed solely as quality assurance technologists, but need to move forward in step with medical and practice advances, becoming recognized as having a leadership role in providing quality research, technological development, and quality patient care.

In this session, four leaders in medical research and healthcare will discuss their observations on how medical physicists have contributed to advancements in healthcare and opportunities to continue leadership in providing quality medicine through the applications of physics to research, education, and clinical practice.

Learning Objectives:

Understand the changes in the healthcare environment and how medical physicists can contribute to improving patient care.

Learn how medical physicists are currently leading research efforts to improve clinical imaging and diagnosis.

Understand the role of medical physicists in developing new technology and leading its translation into clinical care.
MO‐C‐BRB‐03: Delivering Value Outside the Ivory Tower
Authors: Beyer D.
Published: July 2016

With the profound changes currently occurring in medicine, the role of the medical physicist cannot stagnate, but must evolve to meet the challenges and opportunities that are presented. Medical physicists must understand these changes and establish themselves not only as relevant but as leaders in this new environment. We must increase our presence in clinical settings such as tumor boards, patient rounds, and the development of new diagnosis, imaging, and treatment techniques. By establishing ourselves as competent scientists, we can and must participate in the development of technologies through research, teaching, and clinical implementation. As medical physicists we must define our roles and value to our physician colleagues, patients, referring physicians, and senior administrators. We cannot afford to be viewed solely as quality assurance technologists, but need to move forward in step with medical and practice advances, becoming recognized as having a leadership role in providing quality research, technological development, and quality patient care.

In this session, four leaders in medical research and healthcare will discuss their observations on how medical physicists have contributed to advancements in healthcare and opportunities to continue leadership in providing quality medicine through the applications of physics to research, education, and clinical practice.

Learning Objectives:

Understand the changes in the healthcare environment and how medical physicists can contribute to improving patient care.

Learn how medical physicists are currently leading research efforts to improve clinical imaging and diagnosis.

Understand the role of medical physicists in developing new technology and leading its translation into clinical care.
MO‐DE‐204‐00: International Symposium: Patient Dose Reduction in Diagnostic Radiology
Authors: Lief Eugene
Published: July 2016

The main topic of the session is to show how dose optimization is being implemented in various regions of the world, including Europe, Australia, North America and other regions.

A multi‐national study conducted under International Atomic Energy Agency (IAEA) across more than 50 less resourced countries gave insight into patient radiation doses and safety practices in CT, mammography, radiography and interventional procedures, both for children and adults. An important outcome was the capability development on dose assessment and management.

An overview of recent European projects related to CT radiation dose and optimization both to adults and children will be presented. Existing data on DRLs together with a European methodology proposed on establishing and using DRLs for paediatric radiodiagnostic imaging and interventional radiology practices will be shown.

Compared with much of Europe at least, many Australian imaging practices are relatively new to the task of diagnostic imaging dose optimisation. In 2008 the Australian Government prescribed a requirement to periodically compare patient radiation doses with diagnostic reference levels (DRLs), where DRLs have been established. Until recently, Australia had only established DRLs for computed tomography (CT). Regardless, both professional society and individual efforts to improved data collection and develop optimisation strategies across a range of modalities continues. Progress in this field, principally with respect to CT and interventional fluoroscopy will be presented.

In the US, dose reduction and optimization efforts for computed tomography have been promoted and mandated by several organizations and accrediting entities. This presentation will cover the general motivation, implementation, and implications of such efforts.

Learning Objectives:

Understand importance of the dose optimization in Diagnostic Radiology.

See how this goal is achieved in different regions of the World.

Learn about the global trend in the dose optimization and future prospectives.

M. Rehani, The work was a part of the work of IAEA where I was an employee and IAEA is a United Nations organization
MO‐DE‐201‐02: Self Awareness
Authors: Johnson J.
Published: July 2016

Medical physicists possess technical knowledge and problem solving skills required to deliver high quality diagnosis and treatment in the clinic, to provide excellence in research, or to transfer expertise in industrial or regulatory environments. As the healthcare industry rapidly evolves, medical physicists must make a case for ensuring recognition of their value. One of many ways the AAPM is working to ensure stewardship of the profession is through development of the Medical Physics Leadership Academy (MPLA).

This session will provide an introduction to the MPLA and one of its focus areas of emotional intelligence. The session will make the case for emotional competencies in addition to technical competencies. MPLA work group representatives will share consolidated results from conducting 360 feedback assessments used to measure emotional competencies of medical physicists. Some emotional competencies contribute more to professional success than others, and the session will explain how to overcome shortcomings. Two specific emotional competencies will be covered: selfawareness and empathy.

Learning Objectives:

Understand the importance of medical physics leadership in the future of health care

Understand emotional intelligence and emotional competencies and ways they can be measured

Utilize self‐awareness and empathy to improve management of our own emotions and others
MO‐DE‐201‐04: Skits and Panel Discussion
Authors: Miller R.
Published: July 2016

Medical physicists possess technical knowledge and problem solving skills required to deliver high quality diagnosis and treatment in the clinic, to provide excellence in research, or to transfer expertise in industrial or regulatory environments. As the healthcare industry rapidly evolves, medical physicists must make a case for ensuring recognition of their value. One of many ways the AAPM is working to ensure stewardship of the profession is through development of the Medical Physics Leadership Academy (MPLA).

This session will provide an introduction to the MPLA and one of its focus areas of emotional intelligence. The session will make the case for emotional competencies in addition to technical competencies. MPLA work group representatives will share consolidated results from conducting 360 feedback assessments used to measure emotional competencies of medical physicists. Some emotional competencies contribute more to professional success than others, and the session will explain how to overcome shortcomings. Two specific emotional competencies will be covered: selfawareness and empathy.

Learning Objectives:

Understand the importance of medical physics leadership in the future of health care

Understand emotional intelligence and emotional competencies and ways they can be measured

Utilize self‐awareness and empathy to improve management of our own emotions and others