Clinical practice workflow in Radiation Oncology should be highly standardized.
PMID: 30861297 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - March 12, 2019 Category: Physics Authors: Halvorsen P, Gupta N, Rong Y Tags: J Appl Clin Med Phys Source Type: research

Evaluation of mixed energy partial arcs for volumetric modulated arc therapy for prostate cancer.
This study was performed in two parts. For each of the 25 patients in Part 1, two single-energy single-arc plans, a 6 MV-SA plan and a 15 MV-SA plan, and a third MEPA plan involving composite of 6-MV anterior-posterior partial arcs and a 15-MV lateral partial arc weighted 1:2 were created. The dosimetric difference between MEPA(6/15 MV 1:2 weighted) and 6 MV-SA plans, and MEPA(6/15 MV 1:2 weighted) and 15 MV-SA plans were measured. In the Part 2 of this study, a second MEPAs plan (6 MV anterior-posterior arcs and 15 MV lateral arcs weighted 1:1), (MEPA 6/15 MV 1:1 weighted), was...
Source: Journal of Applied Clinical Medical Physics - March 12, 2019 Category: Physics Authors: Momin S, Gräfe JL, Khan RF Tags: J Appl Clin Med Phys Source Type: research

Technical Note: The use of DirectDensityTM and dual-energy CT in the radiation oncology clinic.
CONCLUSIONS: While DD and DECT perform as expected when used independently, errors from their combined use were demonstrated. Dose errors from misuse of the DD kernel with DECT post-processing were as large as 2.5%. The DECT post-processing was without value because the HU differences between low and high energy were removed by the DD kernel. When using DD and DECT, we recommend the use of a DD reconstruction of the high energy scan for the dose calculation, and use of a FBP filter for the low and high energy scans for the DECT post-processing. PMID: 30851087 [PubMed - as supplied by publisher] (Source: Journal of App...
Source: Journal of Applied Clinical Medical Physics - March 9, 2019 Category: Physics Authors: Nelson G, Pigrish V, Sarkar V, Su FC, Salter B Tags: J Appl Clin Med Phys Source Type: research

Development and validation of an open source Monte Carlo dosimetry model for wide-beam CT scanners using Fluka.
CONCLUSION: A Fluka-based Monte Carlo simulation model of axial and helical acquisition techniques using a wide-beam collimation CT scanner demonstrated good agreement between measured and simulated results for both fixed current and TCM in complex and simple geometries. Code and dataset will be made available at https://github.com/chezhia/FLUKA_CT. PMID: 30851155 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - March 9, 2019 Category: Physics Authors: Somasundaram E, Artz NS, Brady SL Tags: J Appl Clin Med Phys Source Type: research

Plan S - what is its meaning for open access journals and for the JACMP?
PMID: 30839145 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - March 6, 2019 Category: Physics Authors: Mills M Tags: J Appl Clin Med Phys Source Type: research

Automatic detection of graticule isocenter and scale from kV and MV images.
CONCLUSION: We developed an approach to robustly and automatically detect graticule isocenter and scale from two-dimensionla (2D) kV and MV films. This is a first step toward automated treatment planning based on 2D x-ray images. PMID: 30843335 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - March 6, 2019 Category: Physics Authors: Fang R, Yang J, Du W, Court L Tags: J Appl Clin Med Phys Source Type: research

Geometric and dosimetric impact of anatomical changes for MR-only radiation therapy for the prostate.
CONCLUSIONS: Variations in the bladder and rectal volume can significantly dislocate the prostate and OARs, which can negatively impact the dose delivered to these organs. This warrants proper preparation of patients during treatment and imaging sessions, especially when imaging required longer scan times such as MR protocols. PMID: 30821881 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - March 1, 2019 Category: Physics Authors: Nejad-Davarani SP, Sevak P, Moncion M, Garbarino K, Weiss S, Kim J, Schultz L, Elshaikh MA, Renisch S, Glide-Hurst C Tags: J Appl Clin Med Phys Source Type: research

Development and validation of a 3D-printed bolus cap for total scalp irradiation.
CONCLUSIONS: We have developed a workflow to 3D-print highly conformal bolus caps for TSI and demonstrated these caps can reproducibly generate a uniform dose to the scalp. PMID: 30821903 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - March 1, 2019 Category: Physics Authors: Baltz GC, Chi PM, Wong PF, Wang C, Craft DF, Kry SF, Lin SSH, Garden AS, Smith SA, Howell RM Tags: J Appl Clin Med Phys Source Type: research

Seasonal variations in measurements of linear accelerator output.
CONCLUSIONS: Results confirm the presence of underlying seasonal variations in measured output from the linear accelerators. The findings identify humidity impact on the measurement device as the underlying cause of the cyclical changes and not the accelerators themselves. These results could help minimize unwarranted machine servicing. PMID: 30817079 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - February 28, 2019 Category: Physics Authors: Bartolac S, Heaton R, Norrlinger B, Letourneau D Tags: J Appl Clin Med Phys Source Type: research

Three discipline collaborative radiation therapy (3DCRT) special debate: I would treat all early-stage NSCLC patients with SBRT.
PMID: 30793828 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - February 22, 2019 Category: Physics Authors: Mohindra P, Sawant A, Griffin RJ, Lamichhane N, Vlashi E, Xu-Welliver M, Dominello M, Joiner MC, Burmeister J Tags: J Appl Clin Med Phys Source Type: research

Whole-body dose equivalent including neutrons is similar for 6 MV and 15 MV IMRT, VMAT, and 3D conformal radiotherapy.
CONCLUSION: The calculated whole-body dose helped to understand the importance of the dose contributions in different areas of the patient. Regarding radiation protection of the patient for IGRT treatments, the choice of beam energy is not important, whereas the treatment technique has a large influence on the out-of-field dose. If the patient is treated with intensity-modulated beams, VMAT should be used instead of dynamic IMRT in terms of radiation protection of the patient. In general, the developed models for photon and neutron dose equivalent calculation can be used for any patient geometry, tumor location, and linear...
Source: Journal of Applied Clinical Medical Physics - February 21, 2019 Category: Physics Authors: Hauri P, Schneider U Tags: J Appl Clin Med Phys Source Type: research

Epid-based in  vivo dose verification for lung stereotactic treatments delivered with multiple breath-hold segmented volumetric modulated arc therapy.
Epid-based in vivo dose verification for lung stereotactic treatments delivered with multiple breath-hold segmented volumetric modulated arc therapy. J Appl Clin Med Phys. 2019 Feb 20;: Authors: Cilla S, Ianiro A, Craus M, Viola P, Deodato F, Macchia G, Buwenge M, Morganti AG, Valentini V, Piermattei A Abstract We evaluated an EPID-based in-vivo dosimetry (IVD) method for the dose verification and the treatment reproducibility of lung SBRT-VMAT treatments in clinical routine. Ten patients with lung metastases treated with Elekta VMAT technique were enrolled. All patients were irradiated in five c...
Source: Journal of Applied Clinical Medical Physics - February 20, 2019 Category: Physics Authors: Cilla S, Ianiro A, Craus M, Viola P, Deodato F, Macchia G, Buwenge M, Morganti AG, Valentini V, Piermattei A Tags: J Appl Clin Med Phys Source Type: research

A multi-institutional evaluation of machine performance check system on treatment beam output and symmetry using statistical process control.
CONCLUSIONS: Machine performance check was verified as a daily quality assurance tool to check machine output and symmetry while assessing against an independent detector on a weekly basis. MPC output detection can be improved by regular SPC-based trend analysis to measure drifts in the inherent device and control systematic and random variations thereby increasing confidence in its capabilities as a QA device. A 3-monthly MPC calibration assessment was recommended based on SPC capability and acceptability calculations. PMID: 30786139 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - February 20, 2019 Category: Physics Authors: Binny D, Aland T, Archibald-Heeren BR, Trapp JV, Kairn T, Crowe SB Tags: J Appl Clin Med Phys Source Type: research

Impact of aeration change and beam arrangement on the robustness of proton plans.
This study determines the impact of change in aeration in sinonasal cavities on the robustness of passive-scattering proton therapy plans in patients with sinonasal and nasopharyngeal malignancies. Fourteen patients, each with one planning CT and one CT acquired during radiotherapy were studied. Repeat and planning CTs were rigidly aligned and contours were transferred using deformable registration. The amount of air, tumor, and fluid within the cavity containing the tumor were measured on both CTs. The original plans were recalculated on the repeat CT. Dosimetric changes were measured for the targets and critical structur...
Source: Journal of Applied Clinical Medical Physics - February 12, 2019 Category: Physics Authors: Shusharina N, Fullerton B, Adams JA, Sharp GC, Chan AW Tags: J Appl Clin Med Phys Source Type: research

Three discipline collaborative radiation therapy (3DCRT) special debate: The United States should build additional proton therapy facilities.
PMID: 30735613 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - February 8, 2019 Category: Physics Authors: Braunstein S, Wang L, Newhauser W, Tenenholz T, Rong Y, van der Kogel A, Dominello M, Joiner MC, Burmeister J Tags: J Appl Clin Med Phys Source Type: research

The effect of respiratory motion on electronic portal imaging device dosimetry.
Abstract There is an increasing need to develop methods for in vivo verification of the delivery of radiotherapy treatments. Electronic portal imaging devices (EPID's) have been demonstrated to be of use for this application. The basic principle is relatively straightforward, the EPID is used to measure a two-dimensional (2D) planar exit or portal dose map behind the patient during the treatment delivery that can provide information on any errors in linear accelerator output or changes in the patient anatomy. In this paper we focused on the effect of intra-fraction motion, particularly respiratory motion, on ...
Source: Journal of Applied Clinical Medical Physics - February 5, 2019 Category: Physics Authors: Fielding AL, Mendieta JB, Maxwell S, Jones C Tags: J Appl Clin Med Phys Source Type: research

Dose evaluation indices for total body irradiation using TomoDirect with different numbers of ports: A comparison with the TomoHelical method.
This study aimed to investigate the relationships between the number of ports and the dose evaluation indices in low-dose TBI in TomoDirect mode using 2-12 ports and to compare these data with those for the TomoHelical mode in a simulation study. Thirteen patients underwent low-dose TBI in TomoHelical mode from June 2015 to June 2016. We used the same computed tomography data sets for these patients to create new treatment plans for upper-body parts using TomoDirect mode with 2-12 beam angles as well as TomoHelical mode. The prescription was 4 Gy in two equal fractions. For the TomoDirect data, we generated plans with...
Source: Journal of Applied Clinical Medical Physics - February 5, 2019 Category: Physics Authors: Kasai Y, Fukuyama Y, Terashima H, Nakamura K, Sasaki T Tags: J Appl Clin Med Phys Source Type: research

Evaluation of dosimetric uncertainty caused by MR geometric distortion in MRI-based liver SBRT treatment planning.
Abstract PURPOSE: MRI-based treatment planning is a promising technique for liver stereotactic-body radiation therapy (SBRT) treatment planning to improve target volume delineation and reduce radiation dose to normal tissues. MR geometric distortion, however, is a source of potential error in MRI-based treatment planning. The aim of this study is to investigate dosimetric uncertainties caused by MRI geometric distortion in MRI-based treatment planning for liver SBRT. MATERIALS AND METHODS: The study was conducted using computer simulations. 3D MR geometric distortion was simulated using measured data in the l...
Source: Journal of Applied Clinical Medical Physics - January 29, 2019 Category: Physics Authors: Han S, Yin FF, Cai J Tags: J Appl Clin Med Phys Source Type: research

Optimal virtual monoenergetic image in "TwinBeam" dual-energy CT for organs-at-risk delineation based on contrast-noise-ratio in head-and-neck radiotherapy.
CONCLUSION: We have proposed a clinically feasible protocol that selects the optimal energy level of the virtual monoenergetic image in TBCT for OAR delineation based on the CNR in head-and-neck OAR. This protocol can be applied in TBCT simulation. PMID: 30693665 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 28, 2019 Category: Physics Authors: Wang T, Ghavidel BB, Beitler JJ, Tang X, Lei Y, Curran WJ, Liu T, Yang X Tags: J Appl Clin Med Phys Source Type: research

Customized double-shell immobilization device combined with VMAT radiation treatment of basosquamous cell carcinoma of the scalp.
This study presents the plan's quality parameters, patient's dosimetry, and patient's outcome. The patient was treated using volume-modulated-arc therapy (VMAT) and a double-shell-bolus full-head device (DSBFD) designed for patient immobilization and better skin coverage. A VMAT plan was generated using an Eclipse treatment-planning system for a prescribed dose of 60 Gy in 30 fractions. The treatment plan was analyzed to determine the conformity index (CI), the homogeneity index (HI), the target-coverage, and the dose to the organs-at-risk (OARs). Skin-doses were measured using optically stimulated luminescence (OSL) ...
Source: Journal of Applied Clinical Medical Physics - January 24, 2019 Category: Physics Authors: Mail N, Al-Ghamdi SM, Chantel C, Sedhu F, Rana A, Saoudi A Tags: J Appl Clin Med Phys Source Type: research

Continued emphasis on quality and safety jeopardizes clinical medical physics careers in radiation oncology: What can be done about it?
PMID: 30680931 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 24, 2019 Category: Physics Authors: Pawlicki T, Mundt AJ Tags: J Appl Clin Med Phys Source Type: research

Radiation dose and image quality comparison during spine surgery with two different, intraoperative 3D imaging navigation systems.
Abstract Careful protocol selection is required during intraoperative three-dimensional (3D) imaging for spine surgery to manage patient radiation dose and achieve clinical image quality. Radiation dose and image quality of a Medtronic O-arm commonly used during spine surgery, and a Philips hybrid operating room equipped with XperCT C-arm 3D cone-beam CT (hCBCT) are compared. The mobile O-arm (mCBCT) offers three different radiation dose settings (low, standard, and high), for four different patient sizes (small, medium, large, and extra large). The patient's radiation dose rate is constant during the entire 3D sc...
Source: Journal of Applied Clinical Medical Physics - January 24, 2019 Category: Physics Authors: Nachabe R, Strauss K, Schueler B, Bydon M Tags: J Appl Clin Med Phys Source Type: research

Development of a Geant4-based independent patient dose validation system with an elaborate multileaf collimator simulation model.
Abstract Despite the improvements in the dose calculation models of the commercial treatment planning systems (TPS), their ability to accurately predict patient dose is still limited. One of the limitations is caused by the simplified model of the multileaf collimator (MLC). The aim of this study was to develop a Monte Carlo (MC) method-based independent patient dose validation system with an elaborate MLC model for more accurate dose evaluation. Varian Clinac 2300 IX was simulated using Geant4 toolkits, after which MC commissioning with measurements was performed to validate the simulation model. A DICOM-RT inter...
Source: Journal of Applied Clinical Medical Physics - January 23, 2019 Category: Physics Authors: Choi HJ, Park H, Shin WG, Kim JI, Min CH Tags: J Appl Clin Med Phys Source Type: research

Dosimetric verification of IMPT using a commercial heterogeneous phantom.
Abstract The purpose of this study was to propose a verification method and results of intensity-modulated proton therapy (IMPT), using a commercially available heterogeneous phantom. We used a simple simulated head and neck and prostate phantom. An ionization chamber and radiochromic film were used for measurements of absolute dose and relative dose distribution. The measured doses were compared with calculated doses using a treatment planning system. We defined the uncertainty of the measurement point of the ionization chamber due to the effective point of the chamber and mechanical setup error as 2 mm and ...
Source: Journal of Applied Clinical Medical Physics - January 23, 2019 Category: Physics Authors: Yasui K, Toshito T, Omachi C, Hayashi K, Kinou H, Katsurada M, Hayashi N, Ogino H Tags: J Appl Clin Med Phys Source Type: research

Comparing phase- and amplitude-gated volumetric modulated arc therapy for stereotactic body radiation therapy using 3D printed lung phantom.
CONCLUSIONS: Considering the dosimetric accuracy and delivery efficacy between the gating methods, amplitude mode is superior to phase mode for gated VMAT treatment. PMID: 30667581 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 22, 2019 Category: Physics Authors: Lee M, Yoon K, Cho B, Kim SS, Song SY, Choi EK, Ahn S, Lee SW, Kwak J Tags: J Appl Clin Med Phys Source Type: research

Dosimetric comparison of VMAT with integrated skin flash to 3D field-in-field tangents for left breast irradiation.
Abstract Volumetric modulated arc therapy (VMAT) has been implemented for left breast irradiation to reduce prescription dose to the heart and improve dose homogeneity across the targeted breast. Our in-house method requires application of a bolus during the optimization process with a target outside of the body, then removing the bolus during the final calculation in order to incorporate skin flash in VMAT plans. To quantify the dosimetric trade-offs between traditional 3D field-in-field tangents and VMAT with integrated skin flash for these patients, we compared nine consecutive patients who recently received ra...
Source: Journal of Applied Clinical Medical Physics - January 17, 2019 Category: Physics Authors: Bogue J, Wan J, Lavey RS, Parsai EI Tags: J Appl Clin Med Phys Source Type: research

Proposed changes to the ACR phantom filling procedure for more accurate and consistent activity concentrations.
CONCLUSION: These improvements allow tighter thresholds to be applied when evaluating image quality and quantitative accuracy of the PET images. These changes also render this phantom data more suitable for inter-PET-scanner harmonization and improve its utility for comparing image reconstruction methods. PMID: 30652408 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 16, 2019 Category: Physics Authors: Beattie BJ Tags: J Appl Clin Med Phys Source Type: research

Do the representative beam data for TrueBeam ™ linear accelerators represent average data?
In this study, we investigated the variation in the beam data for 21 TrueBeam machines collected from 17 institutions with their agreement. In the exponential regions, the percent depth dose (PDD) values showed very small variation,
Source: Journal of Applied Clinical Medical Physics - January 13, 2019 Category: Physics Authors: Tanaka Y, Mizuno H, Akino Y, Isono M, Masai N, Yamamoto T Tags: J Appl Clin Med Phys Source Type: research

Elective nodal irradiation with simultaneous integrated boost stereotactic body radiotherapy for pancreatic cancer: Analyses of planning feasibility and geometrically driven DVH prediction model.
CONCLUSIONS: SIB-SBRT plan with geometrically defined prophylactic areas can be dosimetrically feasible, but including all nodal areas with 25 Gy in five fractions appears to be unrealistic. PMID: 30636367 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 13, 2019 Category: Physics Authors: Nakamura A, Prichard HA, Wo JY, Wolfgang JA, Hong TS Tags: J Appl Clin Med Phys Source Type: research

Output factors of ionization chambers and solid state detectors for mobile intraoperative radiotherapy (IORT) accelerator electron beams.
CONCLUSION: The OFs results of solid state detectors PTW microDiamond and PTW Diode E as well as the ICs with small electrode spacing distance such as IBA PPC05, PTW Advanced Markus and PTW Pinpoint are in excellent agreement with OFMC . The measurements of the other detectors evaluated in this study are less accurate, thus they should be used with caution. Particularly, PTW Diode SRS and IBA NACP-02 are not suitable and their use should be avoided in relative dosimetry measurements under high dose per pulsed (DPP) electron beams. PMID: 30632271 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 10, 2019 Category: Physics Authors: Güngör G, Aydın G, Mustafayev TZ, Özyar E Tags: J Appl Clin Med Phys Source Type: research

Optimization of skin dose using in-vivo MOSFET dose measurements in bolus/non-bolus fraction ratio: A VMAT and a 3DCRT study.
Abstract In-phantom and in-vivo three dimensional conformal radiation therapy (3DCRT) and volumetric modulated arc therapy (VMAT) skin doses, measured with and without bolus in a female anthropomorphic phantom RANDO and in patients, were compared against treatment planning system calculated values. A thorough characterization of the metal oxide semiconductor field effect transistor measurement system was performed prior to the measurements in phantoms and patients. Patients with clinical indication for postoperative external radiotherapy were selected. Skin dose showed higher values with 3DCRT technique compared w...
Source: Journal of Applied Clinical Medical Physics - January 9, 2019 Category: Physics Authors: Dias AG, Pinto DFS, Borges MF, Pereira MH, Santos JAM, Cunha LT, Lencart J Tags: J Appl Clin Med Phys Source Type: research

90 Y SPECT/CT quantitative study and comparison of uptake with pretreatment 99  m Tc-MAA SPECT/CT in radiomicrosphere therapy.
CONCLUSIONS: This study demonstrated correlation in mean TLR between 99m Tc-MAA and 90 Y microsphere SPECT/CT. PMID: 30628156 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - January 9, 2019 Category: Physics Authors: Debebe SA, Adjouadi M, Gulec SA, Franquiz J, McGoron AJ Tags: J Appl Clin Med Phys Source Type: research

Improvements in treatment planning calculations motivated by tightening IMRT QA tolerances.
Abstract Implementing tighter intensity modulated radiation therapy (IMRT) quality assurance (QA) tolerances initially resulted in high numbers of marginal or failing QA results and motivated a number of improvements to our calculational processes. This work details those improvements and their effect on results. One hundred eighty IMRT plans analyzed previously were collected and new gamma criteria were applied and compared to the original results. The results were used to obtain an estimate for the number of plans that would require additional dose volume histogram (DVH)-based analysis and therefore predicted wo...
Source: Journal of Applied Clinical Medical Physics - December 31, 2018 Category: Physics Authors: Stambaugh C, Gagneur J, Uejo A, Clouser E, Ezzell G Tags: J Appl Clin Med Phys Source Type: research

An additional tilted-scan-based CT metal-artifact-reduction method for radiation therapy planning.
CONCLUSIONS: It was confirmed that the proposed method, using complementary information acquired from an additional tilted CT scan, can provide nearly metal-artifact-free images for the treatment planning. PMID: 30597725 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 31, 2018 Category: Physics Authors: Kim C, Pua R, Lee CH, Choi DI, Cho B, Lee SW, Cho S, Kwak J Tags: J Appl Clin Med Phys Source Type: research

Remote dosimetric auditing of clinical trials: The need for vendor specific models to convert images to dose.
Abstract INTRODUCTION: A previous pilot study has demonstrated the feasibility of a novel image-based approach for remote dosimetric auditing of clinical trials. The approach uses a model to convert in-air acquired intensity modulated radiotherapy (IMRT) images to delivered dose inside a virtual phantom. The model was developed using images from an electronic portal imaging device (EPID) on a Varian linear accelerator. It was tuned using beam profiles and field size factors (FSFs) of a series of square fields measured in water tank. This work investigates the need for vendor specific conversion models for image-ba...
Source: Journal of Applied Clinical Medical Physics - December 31, 2018 Category: Physics Authors: Miri N, Vial P, Greer PB Tags: J Appl Clin Med Phys Source Type: research

A quality assurance for respiratory gated proton irradiation with range modulation wheel.
Abstract The purpose of this study was to provide periodic quality assurance (QA) methods for respiratory-gated proton beam with a range modulation wheel (RMW) and to clarify the characteristics and long-term stability of the respiratory-gated proton beam. A two-dimensional detector array and a solid water phantom were used to measure absolute dose, spread-out Bragg peak (SOBP) width and proton range for monthly QA. SOBP width and proton range were measured using an oblique incidence beam to the lateral side of a solid water phantom and compared between with and without a gating proton beam. To measure the delay t...
Source: Journal of Applied Clinical Medical Physics - December 30, 2018 Category: Physics Authors: Yasui K, Shimomura A, Toshito T, Tanaka K, Ueki K, Muramatsu R, Katsurada M, Hayashi N, Ogino H Tags: J Appl Clin Med Phys Source Type: research

Usefulness of hybrid deformable image registration algorithms in prostate radiation therapy.
Abstract To evaluate the accuracy of commercially available hybrid deformable image registration (DIR) algorithms when using planning CT (pCT) and daily cone-beam computed tomography (CBCT) in radiation therapy for prostate cancer. The hybrid DIR algorithms in RayStation and MIM Maestro were evaluated. Contours of the prostate, bladder, rectum, and seminal vesicles (SVs) were used as region-of-interest (ROIs) to guide image deformation in the hybrid DIR and to compare the DIR accuracy. To evaluate robustness of the hybrid DIR for prostate cancer patients with organs with volume that vary on a daily basis, such as ...
Source: Journal of Applied Clinical Medical Physics - December 27, 2018 Category: Physics Authors: Motegi K, Tachibana H, Motegi A, Hotta K, Baba H, Akimoto T Tags: J Appl Clin Med Phys Source Type: research

Extended SSD VMAT treatment for total body irradiation.
In conclusion, the inverse optimized delivery method presented in the paper has been used to deliver homogenous dose to over 100 patients. The method provides superior patient comfort utilizing a commercial TPS. In addition, the ability to easily shield organs at risk is available through the use of MLCs. PMID: 30592152 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 27, 2018 Category: Physics Authors: Pierce G, Balogh A, Frederick R, Gordon D, Yarschenko A, Hudson A Tags: J Appl Clin Med Phys Source Type: research

A novel and innovative device to retract rectum during radiation therapy of pelvic tumors.
Abstract An effective radiotherapy treatment entails maximizing radiation dose to the tumor while sparing the surrounding and normal tissues. With the advent of SBRT with extreme hypo-fractionation in treating tumors including prostate where ablative dose is delivered in smaller number of fractions, rectum remains a dose-limiting organ and at the risk of rectal toxicity or secondary cancer. The same limitation of rectal toxicity exists for high-dose rate (HDR) treatments of cervical, endometrial, or prostate cancer when creating even a short distance between the anterior rectal wall and field of radiation is ideal...
Source: Journal of Applied Clinical Medical Physics - December 26, 2018 Category: Physics Authors: Parsai EI, Jahadakbar A, Lavvafi H, Elahinia M Tags: J Appl Clin Med Phys Source Type: research

Ultra-low dose CT colonography with automatic tube current modulation and sinogram-affirmed iterative reconstruction: Effects on radiation exposure and image quality.
Abstract OBJECTIVE: To assess the radiation dose and image quality of ultra-low dose (ULD)-CT colonography (CTC) obtained with the combined use of automatic tube current (mAs) modulation with a quality reference mAs of 25 and sinogram-affirmed iterative reconstruction (SAFIRE), compared to low-dose (LD) CTC acquired with a quality reference mAs of 55 and reconstructed with filtered back projection (FBP). METHODS: Eighty-two patients underwent ULD-CTC acquisition in prone position and LD-CTC acquisition in supine position. Both ULD-CTC and LD-CTC protocols were compared in terms of radiation dose [weighted vol...
Source: Journal of Applied Clinical Medical Physics - December 26, 2018 Category: Physics Authors: Cianci R, Delli Pizzi A, Esposito G, Timpani M, Tavoletta A, Pulsone P, Basilico R, Cotroneo AR, Filippone A Tags: J Appl Clin Med Phys Source Type: research

Characterization of a new physical phantom for testing rigid and deformable image registration.
Abstract The purpose of this study was to describe a new user-friendly, low-cost phantom that was developed to test the accuracy of rigid and deformable image registration (DIR) systems and to demonstrate the functional efficacy of the new phantom. The phantom was constructed out of acrylic and includes a variety of inserts that simulate different tissue shapes and properties. It can simulate deformations and location changes in patient anatomy by changing the rotations of both the phantom and the inserts. CT scans of this phantom were obtained and used to test the rigid and deformable registration accuracy of the...
Source: Journal of Applied Clinical Medical Physics - December 23, 2018 Category: Physics Authors: Wu RY, Liu AY, Wisdom P, Zhu XR, Frank SJ, Fuller CD, Gunn GB, Palmer MB, Wages CA, Gillin MT, Yang J Tags: J Appl Clin Med Phys Source Type: research

State of the medical physics profession in 2019.
PMID: 30570822 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 20, 2018 Category: Physics Authors: Mills M Tags: J Appl Clin Med Phys Source Type: research

Automatic measurement of air gap for proton therapy using orthogonal x-ray imaging with radiopaque wires.
CONCLUSIONS: An image-based automatic method has been developed to conveniently determine the air gap of a proton beam, directly using the orthogonal images for patient positioning without adding additional imaging dose to the patient. The method provides an objective, accurate, and efficient way to confirm the target depth at treatment to ensure desired target coverage and normal tissue sparing. PMID: 30556259 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 16, 2018 Category: Physics Authors: Ramesh P, Song W, Cao H, Zhao Y, Parikh R, Weiner J, Wang X, Nie K, Yue N, Zhang Y Tags: J Appl Clin Med Phys Source Type: research

Dose prescription with spatial uncertainty for peripheral lung SBRT.
This study investigates the alternative of prescribing to the ITV while including the effects of positional uncertainties. Five patients were retrospectively studied with volumetric modulated arc therapy treatment plans. Five plans were produced for each patient: a static plan prescribed to PTV D95% , three probabilistic plans prescribed to ITV D95% and a static plan re-prescribed to ITV D95% after inverse planning. For the three probabilistic plans, the scatter kernel in the dose calculation was convolved with a spatial uncertainty distribution consisting of either a uniform distribution extending ±5 mm in the...
Source: Journal of Applied Clinical Medical Physics - December 14, 2018 Category: Physics Authors: Bedford JL, Blasiak-Wal I, Hansen VN Tags: J Appl Clin Med Phys Source Type: research

Dosimetric effects of the kV based image-guided radiation therapy of prone breast external beam radiation: Towards the optimized imaging frequency.
Abstract PURPOSE: For prone breast treatment, daily image-guided radiation therapy (IGRT) allows couch shifting to correct breast position relative to the treatment field. This work investigates the dosimetric effect of reducing kV imaging frequencies and the feasibility of optimizing the frequency using patient anatomy or their first 3-day shifts. METHOD: Thirty-seven prone breast patients who had been treated with skin marker alignment followed by daily kV were retrospectively analyzed. Three IGRT schemes (daily-kV, weekly-kV, no-kV) were simulated, assuming that fractions with kV imaging deliver a dose dis...
Source: Journal of Applied Clinical Medical Physics - December 14, 2018 Category: Physics Authors: Xu H, Lee SW, Guerrero M, Yi BY, Chen S, Becker SJ, Chung H, Cheston SB Tags: J Appl Clin Med Phys Source Type: research

An effective method to reduce the interplay effects between respiratory motion and a uniform scanning proton beam irradiation for liver tumors: A case study.
CONCLUSIONS: For liver tumor, this adaptive therapy technique showed significant improvement in dose uniformity even with fewer treatment fractions than normal USPB therapy. PMID: 30548791 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 13, 2018 Category: Physics Authors: Akino Y, Wu H, Oh RJ, Das IJ Tags: J Appl Clin Med Phys Source Type: research

Direct comparison between surface imaging and orthogonal radiographic imaging for SRS localization in phantom.
Abstract PURPOSE: Surface imaging (SI) offers a nonionizing, near real time alternative to radiographic imaging for intrafraction radiosurgery localization. In this work, we systematically compared a commercial SI system vs a commercial room mounted x-ray localization system in phantom. METHODS: An anthropomorphic head phantom with fiducial markers was imaged with linear accelerator on-board x-ray imaging, SI, and room mounted x-ray imaging (RM) at ±45° and ±90° couch angles for three different head tilts and six different isocenters (72 total positions). The shifts generated by the thre...
Source: Journal of Applied Clinical Medical Physics - December 12, 2018 Category: Physics Authors: Wiant D, Liu H, Hayes TL, Shang Q, Mutic S, Sintay B Tags: J Appl Clin Med Phys Source Type: research

Evaluation of plan quality and treatment efficiency for single-isocenter/two-lesion lung stereotactic body radiation  therapy.
CONCLUSION: The SBRT treatment of two peripherally located lung lesions with a centrally placed single-isocenter was dosimetrically equivalent to two-isocenter plans. Faster treatment delivery for single-isocenter treatment can improve patient compliance and reduce the amount of intrafraction motion errors for well-suited patients. PMID: 30548205 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 8, 2018 Category: Physics Authors: Sanford L, Molloy J, Kumar S, Randall M, McGarry R, Pokhrel D Tags: J Appl Clin Med Phys Source Type: research

The commissioning and validation of Monaco treatment planning system on an Elekta VersaHD linear accelerator.
This study describes our experience with beam model validation of a Monaco treatment planning system on a Versa HD linear accelerator. Data were collected such that Monaco beam models could be generated using three algorithms: collapsed cone (CC) and photon Monte Carlo (MC) for photon beams, and electron Monte Carlo (eMC) for electron beams. Validations are performed on measured percent depth doses (PDDs) and profiles, for open-field point-doses in homogenous and heterogeneous media, and for obliquely incident electron beams. Gamma analysis is used to assess the agreement between calculation and measurement for intensity m...
Source: Journal of Applied Clinical Medical Physics - December 7, 2018 Category: Physics Authors: Snyder JE, Hyer DE, Flynn RT, Boczkowski A, Wang D Tags: J Appl Clin Med Phys Source Type: research

EPID-based in  vivo dosimetry using Dosimetry Check™: Overview and clinical experience in a 5-yr study including breast, lung, prostate, and head and neck cancer patients.
CONCLUSIONS: This preliminary data shows that EPID-based IVD with DC may not only be useful in detecting errors but has the potential to be used to establish site-specific dose action levels. The approach is straightforward and has been implemented as a radiographer-led service with no disruption to the patient and no impact on treatment time. PMID: 30536528 [PubMed - as supplied by publisher] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - December 7, 2018 Category: Physics Authors: Nailon WH, Welsh D, McDonald K, Burns D, Forsyth J, Cooke G, Cutanda F, Carruthers LJ, McLaren DB, Puxeu Vaqué J, Kehoe T, Andiappa S Tags: J Appl Clin Med Phys Source Type: research