The impact of the field width on VMAT plan quality and the assessment of half field method.
Abstract PURPOSE: The goal of this work is to investigate the field width dependence of the volumetric modulated arc therapy (VMAT) plan quality and to propose a half field method to irradiate large volumes effectively with VMAT. MATERIALS AND METHODS: We compared four different VMAT methods; namely three full field (3ff), four full field (4ff), three half field (3hf), four half field (4hf). To evaluate the impact of the field width on VMAT plan quality, 12 different size PTVs were created in the virtual phantom and treatment plans generated for each PTV were compared. The effectiveness of our half field meth...
Source: Journal of Applied Clinical Medical Physics - February 20, 2020 Category: Physics Authors: Ugurlu BT, Temelli O Tags: J Appl Clin Med Phys Source Type: research

Modeling the head of PRIMUS linear accelerator for electron-mode at 10 MeV for different applicators.
This study is to validate the utilization of Monte Carlo (MC) simulation to model the head of Primus linear accelerator, thereafter, using it to estimate the energy fluence distribution (EFD), the percentage depth dose (PDD), and beam profiles. MATERIALS AND METHODS: The BEAMNRC code that is based on the EGSNRC code has been used for modeling the linear accelerator head for 10 MeV electron beam with different applicator sizes (10 × 10, 15 × 15, and 20 × 20 cm2 ). The phase space was acquired from BEAMNRC at the end of each applicator and then used as an input f...
Source: Journal of Applied Clinical Medical Physics - February 18, 2020 Category: Physics Authors: Negm H, Aly MMOM, Fathy WM Tags: J Appl Clin Med Phys Source Type: research

Residual setup errors in cranial stereotactic radiosurgery without six degree of freedom robotic couch: Frameless versus rigid immobilization systems.
CONCLUSIONS: With image-guided radiotherapy, translational setup errors can be corrected by image registration between pre-treatment setup CT and planning CT. However, rotational errors cannot be accounted for without a 6 DoF couch. Our study showed that the frameless Aktina immobilization system provided negligible intra-fractional motion. The inter-fractional rotation setup error using Aktina was larger than rigid immobilization with the TALON system. To treat a single lesion far from the center of image registration or for multiple lesions in a single plan, additional margin may be needed to account for the uncorre...
Source: Journal of Applied Clinical Medical Physics - February 18, 2020 Category: Physics Authors: Liu RJ, Yang SX, Neylon J, Hall MD, Dandapani S, Vora N, Wong JYC, Liu A Tags: J Appl Clin Med Phys Source Type: research

Dynamic gating window technique for the reduction of dosimetric error in respiratory-gated spot-scanning particle therapy: An initial phantom study using patient tumor trajectory data.
In this study, we propose a dynamic gating window technique, which optimizes the size of gating window for each spot by considering a possible dosimetric error. The effectiveness of the dynamic gating window technique was evaluated by simulating irradiation using a moving target in a water phantom. In dosimetric characteristics comparison, the dynamic gating window technique exhibited better performance in all evaluation volumes with different effective depths compared with that of the fixed gate approach. The variation of dosimetric characteristics according to the target depth was small in dynamic gate compared to fixed ...
Source: Journal of Applied Clinical Medical Physics - February 18, 2020 Category: Physics Authors: Miyamoto N, Yokokawa K, Takao S, Matsuura T, Tanaka S, Shimizu S, Shirato H, Umegaki K Tags: J Appl Clin Med Phys Source Type: research

Independent review of 4DCT scans used for SABR treatment planning.
In this study, we report on the impact of an image review quality assurance process performed prior to treatment planning by medical physicists for 4DCT scans used for SABR treatment. Reviews were performed of 211 4DCT scans (193 patients) over a 3-yr period (October 2014 to October 2017). Treatment sites included lung (n = 168), kidney/adrenal/adrenal gland (n = 12), rib (n = 4), mediastinum (n = 10), liver (n = 2), T-spine (n = 1), and other abdominal sites (n = 14). It was found that in 23% (n = 49) of cases patient management was altered du...
Source: Journal of Applied Clinical Medical Physics - February 13, 2020 Category: Physics Authors: Antony R, Lonski P, Ungureanu E, Hardcastle N, Yeo A, Siva S, Kron T Tags: J Appl Clin Med Phys Source Type: research

Standardized flattening filter free volumetric modulated arc therapy plans based on anteroposterior width for total body irradiation.
In conclusion, use of FFF beams in VMAT TBI treatment planning resulted in dose homogeneity similar to our current VMAT TBI technique. Clinical dosimetric criteria were achieved for a majority of patients while planning and calculated beam-on times were reduced, offering the possibility of improved patient experience. PMID: 32043760 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - February 11, 2020 Category: Physics Authors: Frederick R, Hudson A, Balogh A, Cao JQ, Pierce G Tags: J Appl Clin Med Phys Source Type: research

Strategies to optimize stereotactic radiosurgery plans for brain tumors with volumetric-modulated arc therapy.
Abstract PURPOSE: Prescription practice in SRS plans for brain tumors differs significantly for different modalities. In this retrospective study, the strategies to optimize SRS plans for brain tumors with volumetric arc therapy (VMAT) were presented. METHODS: Fifty clinically treated cases were stratified by the maximum target size into two groups (≥ 2 cm in 25 cases and
Source: Journal of Applied Clinical Medical Physics - February 11, 2020 Category: Physics Authors: Wang D, DeNittis A, Hu Y Tags: J Appl Clin Med Phys Source Type: research

A technique to generate synthetic CT from MRI for abdominal radiotherapy.
CONCLUSION: A method to generate synthetic CT in the abdomen was developed, and segmentation accuracy and its dosimetric effect were evaluated. Our results demonstrate the potential of using MRI alone for treatment planning in the abdomen. PMID: 32043812 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - February 11, 2020 Category: Physics Authors: Hsu SH, DuPre P, Peng Q, Tomé WA Tags: J Appl Clin Med Phys Source Type: research

Technical Note: Use of automation to eliminate shift errors.
CONCLUSION: Automation can eliminate the common error pathway of providing the wrong shifts to therapists. The scripts have been made available as open-source software for implementation at other radiotherapy clinics. PMID: 32039543 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - February 10, 2020 Category: Physics Authors: Covington EL, Popple RA, Cardan RA Tags: J Appl Clin Med Phys Source Type: research

Flattening filter free VMAT for a stereotactic, single-dose of 30 Gy to lung lesion in a 15-min treatment slot.
Abstract Cone-beam CT-guided single dose of lung stereotactic body radiotherapy (SBRT) treatment with a flattening filter free (FFF) beam and volumetric modulated arc therapy (VMAT) is a safe and highly effective treatment modality for selective small lung lesions. Four-dimensional (4D) CT-based treatment plans were generated using advanced AcurosXB algorithm for heterogeneity corrections. 6X-FFF beam produced highly conformal radiosurgical dose distribution to the target and reduced lung SBRT fraction duration to less than 10 min for a single dose of 30 Gy, significantly improving patient comfort and cl...
Source: Journal of Applied Clinical Medical Physics - February 10, 2020 Category: Physics Authors: Pokhrel D, Sanford L, Dhanireddy B, Molloy J, Randall M, McGarry RC Tags: J Appl Clin Med Phys Source Type: research

Dosimetric evaluation of incorporating the revised V4.0 calibration protocol for breast intraoperative radiotherapy with the INTRABEAM system.
Abstract In breast-targeted intraoperative radiotherapy (TARGIT) clinical trials (TARGIT-B, TARGIT-E, TARGIT-US), a single fraction of radiation is delivered to the tumor bed during surgery with 1.5- to 5.0-cm diameter spherical applicators and an INTRABEAM x-ray source (XRS). This factory-calibrated XRS is characterized by two depth-dose curves (DDCs) named "TARGIT" and "V4.0." Presently, the TARGIT DDC is used to treat patients enrolled in clinical trials; however, the V4.0 DDC is shown to better represent the delivered dose. Therefore, we reevaluate the delivered prescriptions under the TARG...
Source: Journal of Applied Clinical Medical Physics - February 10, 2020 Category: Physics Authors: Shaikh MY, Burmeister J, Scott R, Kumaraswamy LK, Nalichowski A, Joiner MC Tags: J Appl Clin Med Phys Source Type: research

A novel, yet simple MLC-based 3D-crossfire technique for spatially fractionated GRID therapy treatment of deep-seated bulky tumors.
CONCLUSION: The simple MLC-based 3D-crossfire GRID-therapy technique resulted in enhanced target coverage for de-bulking deep-seated bulky tumors, reduced skin toxicity and spare adjacent critical structures. This simple MLC-based approach can be easily adopted by any radiotherapy center. It provides detailed dosimetry and a safe and effective treatment by eliminating the heavy physical GRID-block and could potentially provide same day treatment. Prospective clinical trial with higher tumor-dose to bulky deep-seated tumors is anticipated. PMID: 32034989 [PubMed - as supplied by publisher] (Source: Journal of Applied C...
Source: Journal of Applied Clinical Medical Physics - February 8, 2020 Category: Physics Authors: Pokhrel D, Halfman M, Sanford L, Chen Q, Kudrimoti M Tags: J Appl Clin Med Phys Source Type: research

Dosimetric impact of rotational errors on the quality of VMAT-SRS for multiple brain metastases: Comparison between single- and two-isocenter treatment planning techniques.
CONCLUSION: Limiting the lesion-to-isocenter distance to ≤4 cm by introducing additional isocenter(s) appears to partly mitigate severe target underdosage, especially for smaller target sizes. If OAR-sparing is also a concern, more stringent rotational error tolerances apply. PMID: 32022447 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - February 5, 2020 Category: Physics Authors: Prentou G, Pappas EP, Logothetis A, Koutsouveli E, Pantelis E, Papagiannis P, Karaiskos P Tags: J Appl Clin Med Phys Source Type: research

Centers for medicare & medicaid services radiation oncology alternative payment model and the future of radiation oncology physics practice.
Centers for medicare & medicaid services radiation oncology alternative payment model and the future of radiation oncology physics practice. J Appl Clin Med Phys. 2020 Jan 28;: Authors: Mills M, Solberg T, Halvorsen P PMID: 31990120 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 28, 2020 Category: Physics Authors: Mills M, Solberg T, Halvorsen P Tags: J Appl Clin Med Phys Source Type: research

Method of determining geometric patient size surrogates using localizer images in CT.
CONCLUSION: The model-based magnification method gives an accurate estimate of patient size surrogates extracted from CT localizers that are needed for calculating NDC to achieve accurate SSDE. PMID: 31990136 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 28, 2020 Category: Physics Authors: Burton CS Tags: J Appl Clin Med Phys Source Type: research

Utilizing the TrueBeam Advanced Imaging Package to monitor intrafraction motion with periodic kV imaging and automatic marker detection during VMAT prostate treatments.
CONCLUSIONS: Periodic kV imaging with automatic detection of motion during VMAT prostate treatments is commercially available, and can be successfully implemented to mitigate effects of intrafraction motion with careful attention to software settings. PMID: 31981305 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 24, 2020 Category: Physics Authors: Korpics MC, Rokni M, Degnan M, Aydogan B, Liauw SL, Redler G Tags: J Appl Clin Med Phys Source Type: research

Evaluation of the dosimetric impact of manufacturing variations for the INTRABEAM x-ray source.
CONCLUSION: The American Association of Physicist in Medicine Task Group-167 requires that the impurities in radionuclides used for brachytherapy produce ≤ 5.0% dosimetric variations. Because of differences in an XRS output and DDC, we have demonstrated the dosimetric variations within a 10-mm depth of the applicator surface to be ≤ 2.5%. PMID: 31976605 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 24, 2020 Category: Physics Authors: Shaikh MY, Joiner MC, Nalichowski A, Kumaraswamy LK, Burmeister J Tags: J Appl Clin Med Phys Source Type: research

Impact of the MLC leaf-tip model in a commercial TPS: Dose calculation limitations and IROC-H phantom failures.
This study investigates the dosimetric impact of the MLC leaf-tip model in a commercial TPS (RayStation v.6.1). The detectability of modeling errors was assessed through both measurements with an anthropomorphic head-and-neck phantom and patient-specific IMRT QA using a 3D diode array. METHODS AND MATERIALS: An Agility MLC (Elekta Inc.) was commissioned in RayStation. Nine IMRT and VMAT plans were optimized to treat the head-and-neck phantom from the Imaging and Radiation Oncology Core Houston branch (IROC-H). Dose distributions for each plan were re-calculated on 27 beam models, varying leaf-tip width (2.0, 4.5, and ...
Source: Journal of Applied Clinical Medical Physics - January 21, 2020 Category: Physics Authors: Koger B, Price R, Wang D, Toomeh D, Geneser S, Ford E Tags: J Appl Clin Med Phys Source Type: research

Observer uncertainties of soft tissue-based patient positioning in IGRT.
This study aimed to reveal observer uncertainties of soft-tissue-based patient positioning on cone-beam computed tomography (CBCT) images for prostate cancer IGRT. METHODS: Twenty-six patients (7-8 fractions/patient, total number of 204 fractions) who underwent IGRT for prostate cancer were selected. Six radiation therapists retrospectively measured prostate cancer location errors (PCLEs) of soft-tissue-based patient positioning between planning CT (pCT) and pretreatment CBCT (pre-CBCT) images after automatic bone-based registration. Observer uncertainties were evaluated based on residual errors, which denoted the dif...
Source: Journal of Applied Clinical Medical Physics - January 20, 2020 Category: Physics Authors: Hirose TA, Arimura H, Fukunaga JI, Ohga S, Yoshitake T, Shioyama Y Tags: J Appl Clin Med Phys Source Type: research

A pitfall of using the circular-edge technique with image averaging for spatial resolution measurement in iteratively reconstructed CT images.
We describe a pitfall in MTF measurement using the circular-edge technique with image averaging, and suggest a method to correct it. PMID: 31957969 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 20, 2020 Category: Physics Authors: Narita A, Ohkubo M Tags: J Appl Clin Med Phys Source Type: research

Impact of patient positioning uncertainty in noncoplanar intracranial stereotactic radiotherapy.
Abstract The aim of this study is to evaluate the patient positioning uncertainty in noncoplanar stereotactic radiosurgery or stereotactic radiotherapy (SRS/SRT) for intracranial lesions with the frameless 6D ExacTrac system. In all, 28 patients treated with SRS/SRT of 70 treatment plans at our institution were evaluated in this study. Two X-ray images with the frameless 6D ExacTrac system were first acquired to correct (XC) and verify (XV) the patient position at a couch angle of 0º. Subsequently, the XC and XV images were also acquired at each planned couch angle for using noncoplanar beams to detect positi...
Source: Journal of Applied Clinical Medical Physics - January 20, 2020 Category: Physics Authors: Tanaka Y, Oita M, Inomata S, Fuse T, Akino Y, Shimomura K Tags: J Appl Clin Med Phys Source Type: research

A technique to reduce skin toxicity in radiotherapy treatment planning for esophageal cancer.
In this study, we copied the previously delivered plans in radiotherapy treatment planning system and converted a low dose level (usually 5Gy) to a skin dose limiting structure (SDLS), then we set the objective functions of the SDLS in the Pinnacle Inverse Planning module and re-optimize the plans to reduce the skin doses. Finally, we compared the dose distribution and other parameters of target volume and organs at risk (OARs) between the old plans and the new plans. RESULTS: There was no significant difference in most of OARs sparing. However, for all plans, the maximum dose to the SDLS decreased from 6145.90 &...
Source: Journal of Applied Clinical Medical Physics - January 11, 2020 Category: Physics Authors: Yang W, Yang Z, Zhao T, Ding W, Kong W, Wang P, Ye H, Zhang Z, Shang J Tags: J Appl Clin Med Phys Source Type: research

Comparison of radiation dose and image quality between flat panel computed tomography and multidetector computed tomography in a hybrid CT-angiography suite.
Abstract The purpose of this study was to compare, using the same radiation dose and image quality metrics, flat panel computed tomography (FPCT) to multidetector CT (MDCT) in interventional radiology. A single robotic angiography system with FPCT was compared to a single MDCT system, both installed in a hybrid CT-angiography laboratory and both operating under automatic exposure control. Radiation dose was measured on the central axis (Dc ) of a CT dosimetry phantom 30 cm in diameter and 60 cm in length using default protocols for FPCT and MDCT with the imaged length in MDCT matched to the field of view...
Source: Journal of Applied Clinical Medical Physics - January 10, 2020 Category: Physics Authors: Jones AK, Odisio BC Tags: J Appl Clin Med Phys Source Type: research

Evaluation and verification of a simplified lead equivalency measurement method.
CONCLUSION: This work validates the test tool and methodology as an inexpensive alternative to checking the lead equivalency of radiation protection apparel in a clinical setting. The methodology is equipment independent with a few prerequisites. PMID: 31916401 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 8, 2020 Category: Physics Authors: Wargo RR, Aljabal AF, Lin PP Tags: J Appl Clin Med Phys Source Type: research

Analyses of integrated EPID images for on-treatment quality assurance to account for interfractional variations in volumetric modulated arc therapy.
CONCLUSIONS: Analyses of the on-treatment EPID images facilitates estimates of the interfractional anatomical variation in HNC patients during VMAT and thus improves assessments of the need for re-planning or adaptive strategies and the timing thereof. PMID: 31909889 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 7, 2020 Category: Physics Authors: Matsushita N, Nakamura M, Sasaki M, Yano S, Yoshimura M, Mizowaki T Tags: J Appl Clin Med Phys Source Type: research

Dose and blending fraction quantification for adaptive statistical iterative reconstruction based on low-contrast detectability in abdomen CT.
CONCLUSION: The parametric model can be used to form a look-up-table for dose and ASIR blending fraction. The dose choices may be substantially limited in some cases depending on the required LCD. PMID: 31898865 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 3, 2020 Category: Physics Authors: Zhou Y Tags: J Appl Clin Med Phys Source Type: research

The use of 0.5rcav as an effective point of measurement for cylindrical chambers may result in a systematic shift of electron percentage depth doses.
This study investigated the effect that the selection of EPOM shift for cylindrical chamber has on percentage depth dose (PDD) curves. Depth dose curves were measured in a water phantom for electron beams with energies ranging from 6 to 18 MeV. The detectors investigated were of three different types: diodes (Diode-E PTW 60017 and SFD IBA), cylindrical (Semiflex PTW 31010, PinPoint PTW 31015, and A12 Exradin), and parallel plate ionization chambers (Advanced Markus PTW 34045 and Markus PTW 23343). Depth dose curves measured with Diode-E and Advanced Markus agreed within 0.2 mm at R50 except for 18 MeV and ex...
Source: Journal of Applied Clinical Medical Physics - January 3, 2020 Category: Physics Authors: Anusionwu PC, Alpuche Aviles JE, Pistorius S Tags: J Appl Clin Med Phys Source Type: research

Sensitivity analysis of Monte Carlo model of a gantry-mounted passively scattered proton system.
CONCLUSIONS: This study revealed the importance of considering detailed beam parameters, and identifying those that resulted in large effects on the physical dose distribution and LETs for a compact proton therapy machine. PMID: 31898873 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 3, 2020 Category: Physics Authors: Baradaran-Ghahfarokhi M, Reynoso F, Prusator MT, Sun B, Zhao T Tags: J Appl Clin Med Phys Source Type: research

Optimization of HU threshold for coronary artery calcium scans reconstructed at 0.5-mm slice thickness using iterative reconstruction.
CONCLUSION: The optimized HU thresholds were proposed for CAC scans reconstructed at 0.5-mm slice thickness using IR. Our study results may provide a potential strategy to improve the reliability of calcium scoring by reducing partial volume effect while keeping radiation dose as low as reasonably achievable. PMID: 31889419 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 30, 2019 Category: Physics Authors: Hou KY, Tsujioka K, Yang CC Tags: J Appl Clin Med Phys Source Type: research

Dosimetric study of three-dimensional static and dynamic SBRT radiotherapy for hepatocellular carcinoma based on 4DCT image deformable registration.
Abstract The purpose of this work was to determine the actual dose received by normal tissues during four-dimensional radiation therapy (4DRT) composed of ten phases of four-dimensional computer tomography (4DCT) images. The analysis was performed by tracking the hepatocellular carcinoma SBRT. Data were acquired from the tracking of each phase with the beam aperture for 28 hepatocellular carcinoma patients, and the data were used to generate a cumulative plan, which was compared to a three-dimensional (3D) plan formed from a merged target volume based on 4DCT images in a radiation treatment planning system (TPS). ...
Source: Journal of Applied Clinical Medical Physics - December 30, 2019 Category: Physics Authors: Ma C, Duan J, Yu S, Ma C Tags: J Appl Clin Med Phys Source Type: research

Sample content of kinesthetic educational training: Reducing scattered X-ray exposures to interventional physician operators of fluoroscopy.
Abstract Content used by Medical Physicists for fluoroscopy safety training to staff is deliverable via several formats, that is, online content or a live audience slide presentations. Here, we share one example of a kinesthetic (live, hands-on simulation) educational program in use at our facility for some time (~10 years). In this example, the format and content specifically target methods of reducing physician operator exposures from scattered x rays. A kinesthetic format identifies and promotes the adoption of exposure-reducing behaviors. Key kinesthetic elements of this type of training include: physicia...
Source: Journal of Applied Clinical Medical Physics - December 30, 2019 Category: Physics Authors: Pavlicek W, Sensakovic WF, Zhou Y, Paden RG, Panda A, Hines J, Naidu SG, Oklu R Tags: J Appl Clin Med Phys Source Type: research

Evaluation of the IAEA-TRS  483 protocol for the dosimetry of small fields (square and stereotactic cones) using multiple detectors.
Evaluation of the IAEA-TRS 483 protocol for the dosimetry of small fields (square and stereotactic cones) using multiple detectors. J Appl Clin Med Phys. 2019 Dec 30;: Authors: Smith CL, Montesari A, Oliver CP, Butler DJ Abstract The IAEA TRS 483 protocol1 for the dosimetry of small static fields in radiotherapy was used to calculate output factors for the Elekta Synergy linac at the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). Small field output factors for both square and circular fields were measured using nine different detectors. The "corrected" output facto...
Source: Journal of Applied Clinical Medical Physics - December 30, 2019 Category: Physics Authors: Smith CL, Montesari A, Oliver CP, Butler DJ Tags: J Appl Clin Med Phys Source Type: research

Analysis of treatment process time for real-time-image gated-spot-scanning proton-beam therapy (RGPT) system.
Abstract We developed a synchrotron-based real-time-image gated-spot-scanning proton-beam therapy (RGPT) system and utilized it to clinically operate on moving tumors in the liver, pancreas, lung, and prostate. When the spot-scanning technique is linked to gating, the beam delivery time with gating can increase, compared to that without gating. We aim to clarify whether the total treatment process can be performed within approximately 30 min (the general time per session in several proton therapy facilities), even for gated-spot-scanning proton-beam delivery with implanted fiducial markers. Data from 152 pati...
Source: Journal of Applied Clinical Medical Physics - December 30, 2019 Category: Physics Authors: Yoshimura T, Shimizu S, Hashimoto T, Nishioka K, Katoh N, Inoue T, Taguchi H, Yasuda K, Matsuura T, Takao S, Tamura M, Ito YM, Matsuo Y, Tamura H, Horita K, Umegaki K, Shirato H Tags: J Appl Clin Med Phys Source Type: research

Dynamic conformal arcs for lung stereotactic body radiation therapy: A comparison with volumetric-modulated arc therapy.
This study constitutes a feasibility assessment of dynamic conformal arc (DCA) therapy as an alternative to volumetric-modulated arc therapy (VMAT) for stereotactic body radiation therapy (SBRT) of lung cancer. The rationale for DCA is lower geometric complexity and hence reduced risk for interplay errors induced by respiratory motion. Forward planned DCA and inverse planned DCA based on segment-weight optimization were compared to VMAT for single arc treatments of five lung patients. Analysis of dose-volume histograms and clinical goal fulfillment revealed that DCA can generate satisfactory and near equivalent dosimetric ...
Source: Journal of Applied Clinical Medical Physics - December 27, 2019 Category: Physics Authors: Bokrantz R, Wedenberg M, Sandwall P Tags: J Appl Clin Med Phys Source Type: research

Impact of image preprocessing methods on reproducibility of radiomic features in multimodal magnetic resonance imaging in glioblastoma.
In this study, for each patient 1461 radiomics features were extracted from GBM subregions (i.e., edema, necrosis, enhancement, and tumor) of mMRI (i.e., FLAIR, T1, T1C, and T2) volumes for five preprocessing combinations (in total 116 880 radiomics features). The robustness and reproducibility of the radiomics features were assessed under four comparisons: (a) Baseline versus modified bias field; (b) Baseline versus modified bias field followed by noise filtering; (c) Baseline versus modified noise, and (d) Baseline versus modified noise followed bias field correction. The concordance correlation coefficient (CCC), d...
Source: Journal of Applied Clinical Medical Physics - December 27, 2019 Category: Physics Authors: Moradmand H, Aghamir SMR, Ghaderi R Tags: J Appl Clin Med Phys Source Type: research

Expanding the reach of medical physics: Immunotherapy should be included as part of the curriculum for medical physics education and training.
PMID: 31863527 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 20, 2019 Category: Physics Authors: Lamichhane N, Studenski MT, Rong Y Tags: J Appl Clin Med Phys Source Type: research

The 20th anniversary of the JACMP.
PMID: 31859428 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 20, 2019 Category: Physics Authors: Mills M Tags: J Appl Clin Med Phys Source Type: research

Quantification and homogenization of image noise between two CT scanner models.
Abstract Feedback from radiologists indicated that differences in image appearance and noise impeded reading of post-contrast computed tomography (CT) scans from an updated CT scanner that was recently added to a fleet of existing scanners from the same vendor, despite using identically named reconstruction algorithms. The goals of this work were to quantify and possibly standardize image quality on the new and an existing scanner using phantom images. Three months of daily quality control images were analyzed to determine the mean CT number and noise magnitude in a water phantom. Next, subtraction images from the...
Source: Journal of Applied Clinical Medical Physics - December 20, 2019 Category: Physics Authors: Einstein SA, Rong XJ, Jensen CT, Liu X Tags: J Appl Clin Med Phys Source Type: research

FFF-VMAT for SBRT of lung lesions: Improves dose coverage at tumor-lung interface compared to flattened beams.
CONCLUSION: While prescribing dose to the tumor periphery, 6X-FFF VMAT plans for stereotactic single-dose lung SBRT provided similar target coverage with better dose conformity, superior intermediate dose-spillage (improved dose coverage at tumor interface), and improved OAR sparing compared to traditional 6X-FF beams and significantly reduced treatment time. The ipsilateral lung density and tumor location considerably affected dose distributions requiring special attention for clinical SBRT plan optimization on a per-patient basis. Clinical follow up of these patients for tumor local-control rate and treatment-related tox...
Source: Journal of Applied Clinical Medical Physics - December 20, 2019 Category: Physics Authors: Pokhrel D, Halfman M, Sanford L Tags: J Appl Clin Med Phys Source Type: research

MOSFET dosimeter characterization in MR-guided radiation therapy (MRgRT) Linac.
CONCLUSION: MOSFET dosimeters are not affected by the 0.345 T magnetic field in MRgRT system. They showed physics parameters and performance comparable to TLD and ionization chamber; thus, they constitute an alternative to TLD for real-time in-vivo dosimetry in MRgRT procedures. PMID: 31854078 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 18, 2019 Category: Physics Authors: Yadav P, Hallil A, Tewatia D, Dunkerley DAP, Paliwal B Tags: J Appl Clin Med Phys Source Type: research

Treatment planning of VMAT and step-and-shoot IMRT delivery techniques for single fraction spine SBRT: An intercomparative dosimetric analysis and phantom-based quality assurance measurements.
CONCLUSION: From our clinically treated plans, we found that VMAT plans provided better dosimetric quality and comparable delivery accuracy when compared to ssIMRT for single fraction spine SBRT. PMID: 31821729 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 10, 2019 Category: Physics Authors: Ouyang Z, LaHurd DV, Balagamwala EH, Chao ST, Suh JH, Xia P Tags: J Appl Clin Med Phys Source Type: research

"Dose of the day" based on cone beam computed tomography and deformable image registration for lung cancer radiotherapy.
CONCLUSION: This study demonstrated a reasonable agreement in dose-volume metrics between dose accumulation based on vCT and rCT, with the exception for cases with poor CBCT image quality. These findings suggest potential utility of vCT for providing a reasonable estimate of the "dose of the day", and thus facilitating the process of ART for lung cancer. PMID: 31816170 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 9, 2019 Category: Physics Authors: Yuan Z, Rong Y, Benedict SH, Daly ME, Qiu J, Yamamoto T Tags: J Appl Clin Med Phys Source Type: research

Evaluation of complexity and deliverability of prostate cancer treatment plans designed with a knowledge-based VMAT planning technique.
Abstract PURPOSE: Knowledge-based planning (KBP) techniques have been reported to improve plan quality, efficiency, and consistency in radiation therapy. However, plan complexity and deliverability have not been addressed previously for treatment plans guided by an established in-house KBP system. The purpose of this work was to assess dosimetric, mechanical, and delivery properties of plans designed with a common KBP method for prostate cases treated via volumetric modulated arc therapy (VMAT). METHODS: Thirty-one prostate patients previously treated with VMAT were replanned with an in-house KBP method based...
Source: Journal of Applied Clinical Medical Physics - December 9, 2019 Category: Physics Authors: Wall PDH, Fontenot JD Tags: J Appl Clin Med Phys Source Type: research

Small-field dosimetry of TrueBeamTM flattened and flattening filter-free beams: A multi-institutional analysis.
CONCLUSION: In this study, the inter-unit variability of small-field dosimetry was evaluated for TrueBeam linear accelerators. The variations were large at a field size of 5 × 5 mm2 , and most occurred in a detector-dependent manner. PMID: 31816176 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 9, 2019 Category: Physics Authors: Akino Y, Mizuno H, Isono M, Tanaka Y, Masai N, Yamamoto T Tags: J Appl Clin Med Phys Source Type: research

Characterization of continuous bed motion effects on patient breathing and respiratory motion correction in PET/CT imaging.
In this study, we investigated the effect of CBM versus SS on patient breathing and respiratory motion correction. One hundred patients referred for PET/CT were scanned using a Siemens mCT scanner. Patient respiratory waveforms were recorded using an Anzai system and analyzed using four methods: Methods 1 and 2 measured the coefficient of variation (COV) of the respiratory cycle duration (RCD) and amplitude (RCA). Method 3 measured the respiratory frequency signal prominence (RSP) and method 4 measured the width of the HDChest optimal gate (OG) window when using a 35% duty cycle. Waveform analysis was performed over the ab...
Source: Journal of Applied Clinical Medical Physics - December 9, 2019 Category: Physics Authors: Meier JG, Erasmus JJ, Gladish GW, Peterson CB, Diab RH, Mawlawi OR Tags: J Appl Clin Med Phys Source Type: research

Evaluation of the accuracy of deformable image registration on MRI with a physical phantom.
Abstract BACKGROUND AND PURPOSE: Magnetic resonance imaging (MRI) has gained popularity in radiation therapy simulation because it provides superior soft tissue contrast, which facilitates more accurate target delineation compared with computed tomography (CT) and does not expose the patient to ionizing radiation. However, image registration errors in commercial software have not been widely reported. Here we evaluated the accuracy of deformable image registration (DIR) by using a physical phantom for MRI. METHODS AND MATERIALS: We used the "Wuphantom" for end-to-end testing of DIR accuracy for MRI....
Source: Journal of Applied Clinical Medical Physics - December 6, 2019 Category: Physics Authors: Wu RY, Liu AY, Yang J, Williamson TD, Wisdom PG, Bronk L, Gao S, Grosshan DR, Fuller DC, Gunn GB, Ronald Zhu X, Frank SJ Tags: J Appl Clin Med Phys Source Type: research

A daily end-to-end quality assurance workflow for MR-guided online adaptive radiation therapy on MR-Linac.
CONCLUSIONS: The comprehensive end-to-end QA workflow can efficiently check the performance and communication between different components in MRgOART and has been successfully implemented for daily clinical practice. PMID: 31799753 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 4, 2019 Category: Physics Authors: Chen X, Ahunbay E, Paulson ES, Chen G, Li XA Tags: J Appl Clin Med Phys Source Type: research

AAPM medical physics practice guideline 7.a.: Supervision of medical physicist assistants.
Abstract The American Association of Physicists in Medicine (AAPM) is a nonprofit professional society whose primary purposes are to advance the science, education and professional practice of medical physics. The AAPM has more than 8,000 members and is the principal organization of medical physicists in the United States. The AAPM will periodically define new practice guidelines for medical physics practice to help advance the science of medical physics and to improve the quality of service to patients throughout the United States. Existing medical physics practice guidelines will be reviewed for the purpose of r...
Source: Journal of Applied Clinical Medical Physics - December 4, 2019 Category: Physics Authors: Seibert JA, Blatnica AP, Clements JB, Halvorsen PH, Herman MG, Johnson JL, Schueler BA, Martin MC, Palta JR, Pfeiffer DE, Pizzutiello RJ, Prisciandaro JI, Sherouse GW Tags: J Appl Clin Med Phys Source Type: research

Nuclear halo measurements for accurate prediction of field size factor in a Varian ProBeam proton PBS system.
CONCLUSIONS: If the in-air halo for low-energy proton beams is not fully modeled by the TPS, this could potentially lead to under-dosing small, shallow treatment volumes in PBS treatment plans. PMID: 31793202 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 2, 2019 Category: Physics Authors: Harms J, Chang CW, Zhang R, Lin L Tags: J Appl Clin Med Phys Source Type: research

A study of nonuniform CTV to PTV margin expansion incorporating both rotational and translational uncertainties.
CONCLUSION: Nonuniform margin algorithm could avoid excessive compensation for the CTV boundary points near isocenter. This method could be used for clinical margin determination and might be useful for the protection of risk organs. PMID: 31793203 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 2, 2019 Category: Physics Authors: Miao J, Xu Y, Tian Y, Liu Z, Dai J Tags: J Appl Clin Med Phys Source Type: research