Application programming in C# environment with recorded user software interactions and its application in autopilot of VMAT/IMRT treatment planning.
Abstract An autopilot scheme of volumetric-modulated arc therapy (VMAT)/intensity-modulated radiation therapy (IMRT) planning with the guidance of prior knowl-edge is established with recorded interactions between a planner and a commercial treatment planning system (TPS). Microsoft (MS) Visual Studio Coded UI is applied to record some common planner-TPS interactions as subroutines. The TPS used in this study is a Windows-based Eclipse system. The interactions of our application program with Eclipse TPS are realized through a series of subrou-tines obtained by prerecording the mouse clicks or keyboard strokes of a...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Wang H, Xing L Tags: J Appl Clin Med Phys Source Type: research

The dosimetric impact of control point spacing for sliding gap MLC fields.
Abstract Dynamic sliding gap multileaf collimator (MLC) fields are used to model MLC properties within the treatment planning system (TPS) for dynamic treatments. One of the key MLC properties in the Eclipse TPS is the dosimetric leaf gap (DLG) and precise determination of this parameter is paramount to ensuring accurate dose delivery. In this investigation, we report on how the spacing between control points (CPs) for sliding gap fields impacts the dose delivery, MLC positioning accuracy, and measurement of the DLG. The central axis dose was measured for sliding gap MLC fields with gap widths ranging from 2 to 40...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Zwan BJ, Hindmarsh J, Seymour E, Kandasamy K, Sloan K, David R, Lee C Tags: J Appl Clin Med Phys Source Type: research

Investigation of dosimetric differences between the TMR 10 and convolution algorithm for Gamma Knife stereotactic radiosurgery.
Abstract Since its inception, doses applied using Gamma Knife Radiosurgery (GKR) have been calculated using a simple TMR algorithm, which assumes the patient's head is of even density, the same as water. This results in a significant approximation of the dose delivered by the Gamma Knife. We investigated how GKR dose cal-culations varied when using a new convolution algorithm clinically available for GKR planning that takes into account density variations in the head compared with the established calculation algorithm. Fifty-five patients undergoing GKR and harboring 85 lesions were voluntarily and prospectively e...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Rojas-Villabona A, Kitchen N, Paddick I Tags: J Appl Clin Med Phys Source Type: research

Experimental evaluation of a GPU-based Monte Carlo dose calculation algorithm in the Monaco treatment planning system.
Abstract A new GPU-based Monte Carlo dose calculation algorithm (GPUMCD), devel-oped by the vendor Elekta for the Monaco treatment planning system (TPS), is capable of modeling dose for both a standard linear accelerator and an Elekta MRI linear accelerator. We have experimentally evaluated this algorithm for a standard Elekta Agility linear accelerator. A beam model was developed in the Monaco TPS (research version 5.09.06) using the commissioned beam data for a 6 MV Agility linac. A heterogeneous phantom representing several scenarios - tumor-in-lung, lung, and bone-in-tissue - was designed and built. Dose calcu...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Paudel MR, Kim A, Sarfehnia A, Ahmad SB, Beachey DJ, Sahgal A, Keller BM Tags: J Appl Clin Med Phys Source Type: research

A comparison of methods for monitoring photon beam energy constancy.
We examined changes in these energy metrics when photon energies were changed to ± 5% and ± 10% from their nominal energies: 1) an attenuation-based metric (the percent depth dose at 10 cm depth, PDD(10)) and, 2) profile-based metrics, including flatness (Flat) and off-axis ratios (OARs) measured on the orthogonal axes or on the diagonals (diagonal normalized flatness, FDN). Profile-based metrics were measured near dmax and also near 10 cm depth in water (using a 3D scanner) and with ioniza-tion chamber array (ICA). PDD(10) was measured only in water. Changes in PDD, OAR, and FDN were nearly linear to the cha...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Gao S, Balter PA, Rose M, Simon WE Tags: J Appl Clin Med Phys Source Type: research

Dosimetric comparison of intensity-modulated radiotherapy and volumetric-modulated arc radiotherapy in patients with prostate cancer: a meta-analysis.
Abstract Intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) are two main radiotherapy techniques. The aim of this study is to explore which is the preferred technique in prostate treatment through the related publica-tions and meta-analysis. Two authors independently identified all relevant articles available regarding eligibility criteria on PubMed, Embase, and Cochrane Library databases until December 2015. Publication bias was evaluated with funnel plot, and statistical analyses were performed with Stata software. P < 0.05 was thought statistically significant. Ten studie...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Ren W, Sun C, Lu N, Xu Y, Han F, Liu YP, Dai J Tags: J Appl Clin Med Phys Source Type: research

Development and evaluation of a clinical model for lung cancer patients using stereotactic body radiotherapy (SBRT) within a knowledge-based algorithm for treatment planning.
Abstract The purpose of this study was to describe the development of a clinical model for lung cancer patients treated with stereotactic body radiotherapy (SBRT) within a knowledge-based algorithm for treatment planning, and to evaluate the model performance and applicability to different planning techniques, tumor locations, and beam arrangements. 105 SBRT plans for lung cancer patients previously treated at our institution were included in the development of the knowledge-based model (KBM). The KBM was trained with a combination of IMRT, VMAT, and 3D CRT techniques. Model performance was validated with 25 cases...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Snyder KC, Kim J, Reding A, Fraser C, Gordon J, Ajlouni M, Movsas B, Chetty IJ Tags: J Appl Clin Med Phys Source Type: research

The dose penumbra of a custom-made shield used in hemibody skin electron irradiation.
We report our technique for hemibody skin electron irradiation with a custom-made plywood shield. The technique is similar to our clinical total skin electron irradiation (TSEI), performed with a six-pair dual field (Stanford technique) at an extended source-to-skin distance (SSD) of 377 cm, with the addition of a plywood shield placed at 50 cm from the patient. The shield is made of three layers of stan-dard 5/8'' thick plywood (total thickness of 4.75 cm) that are clamped securely on an adjustable-height stand. Gafchromic EBT3 films were used in assessing the shield's transmission factor and the extent of the dose penumb...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Rivers CI, AlDahlawi I, Wang IZ, Singh AK, Podgorsak MB Tags: J Appl Clin Med Phys Source Type: research

Volumetric-modulated arc therapy using multicriteria optimization for body and extremity sarcoma.
This study evaluates the implementation of volumetric-modulated arc therapy (VMAT) using multicriteria optimization (MCO) in the RayStation treatment planning system (TPS) for complex sites, namely extremity and body sarcoma. The VMAT-MCO algorithm implemented in RayStation is newly developed and requires an integrated, comprehensive analysis of plan generation, delivery, and treatment efficiency. Ten patients previously treated by intensity-modulated radiation therapy (IMRT) with MCO were randomly selected and replanned using VMAT-MCO. The plan quality was compared using homogeneity index (HI) and conformity index (CI) of...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Young MR, Craft DL, Colbert CM, Remillard K, Vanbenthuysen L, Wang Y Tags: J Appl Clin Med Phys Source Type: research

EPID-based dosimetry to verify IMRT planar dose distribution for the aS1200 EPID and FFF beams.
Abstract We proposed to perform a basic dosimetry commissioning on a new imager sys-tem, the Varian aS1200 electronic portal imaging device (EPID) and TrueBeam 2.0 linear accelerator for flattened (FF) and flattening filter-free (FFF) beams, then to develop an image-based quality assurance (QA) model for verification of the system delivery accuracy for intensity-modulated radiation therapy (IMRT) treat-ments. For dosimetry testing, linearity of dose response with MU, imager lag, and effectiveness of backscatter shielding were investigated. Then, an image-based model was developed to convert images to planar dose o...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Miri N, Keller P, Zwan BJ, Greer P Tags: J Appl Clin Med Phys Source Type: research

Real-time in vivo dosimetry for SBRT prostate treatment using plastic scintillating dosimetry embedded in a rectal balloon: a case study.
Abstract A novel FDA approved in vivo dosimetry device system using plastic scintillating detectors placed in an endorectal balloon to provide real-time in vivo dosimetry for prostatic rectal interface was tested for use with stereotactic body radiotherapy (SBRT). The system was used for the first time ever to measure dose during linear accelerator based SBRT. A single patient was treated with a total dose of 36.25 Gy given in 5 fractions. Delivered dose was measured for each treatment with the detectors placed against the anterior rectal wall near the prostate rectal interface. Measured doses showed varying degre...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Cantley JL, Cheng CW, Jesseph FB, Podder TK, Colussi VC, Traughber BJ, Ponsky LE Tags: J Appl Clin Med Phys Source Type: research

Gafchromic EBT-XD film: Dosimetry characterization in high-dose, volumetric-modulated arc therapy.
Abstract Radiochromic films are important tools for assessing complex dose distributions. Gafchromic EBT-XD films have been designed for optimal performance in the 40-4,000 cGy dose range. We investigated the dosimetric characteristics of these films, including their dose-response, postexposure density growth, and dependence on scanner orientation, beam energy, and dose rate with applications to high-dose volumetric-modulated arc therapy (VMAT) verification. A 10 MV beam from a TrueBeam STx linear accelerator was used to irradiate the films with doses in the 0-4,000 cGy range. Postexposure coloration was analyzed ...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Miura H, Ozawa S, Hosono F, Sumida N, Okazue T, Yamada K, Nagata Y Tags: J Appl Clin Med Phys Source Type: research

A comprehensive evaluation of adaptive daily planning for cervical cancer HDR brachytherapy.
This study included 22 cervical cancer patients who underwent 5 fractions of HDR-BT. Regions of interest (ROIs) including high-risk clinical tumor volume (HR-CTV) and organs at risk (OARs) were manually contoured on daily CT images. All patients were clinically treated with adaptive daily plans (ADP), which involved ROI delineation and dose optimization at each treatment fraction. Single treatment plans (SP) were retrospectively generated by applying the first treatment fraction's dwell times adjusted for decay and dwell positions of the applicator to subsequent treatment fractions. Various existing similarity metrics were...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Meerschaert R, Nalichowski A, Burmeister J, Paul A, Miller S, Hu Z, Zhuang L Tags: J Appl Clin Med Phys Source Type: research

Dose reduction in CT urography and vasculature phantom studies using model-based iterative reconstruction.
Abstract To evaluate the feasibility of radiation dose reduction using model-based iterative reconstruction (MBIR) for evaluating the ureters and vasculature in a phantom, a tissue-equivalent CT dose phantom was scanned using a 64-channel CT scan-ner. Tubes of varying diameters filled with different dilutions of a contrast agent, simulating ureters or vessels, were inserted into the center of the phantom. Each combination was scanned using an existing renal protocol at 140 kVp or 120 kVp, yielding a display volumetric CT dose index (CTDIvol) of 24 mGy. The scans were repeated using reduced scan techniques to achie...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Page L, Wei W, Kundra V, Rong J Tags: J Appl Clin Med Phys Source Type: research

Evaluation of digital radiography practice using exposure index tracking.
Abstract Some digital radiography (DR) detectors and software allow for remote download of exam statistics, including image reject status, body part, projection, and exposure index (EI). The ability to have automated data collection from multiple DR units is conducive to a quality control (QC) program monitoring institutional radiographic exposures. We have implemented such a QC program with the goal to identify outliers in machine radiation output and opportunities for improvement in radiation dose levels. We studied the QC records of four digital detectors in greater detail on a monthly basis for one year. Altho...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Scott AW, Zhou Y, Allahverdian J, Nute JL, Lee C Tags: J Appl Clin Med Phys Source Type: research

Development of a universal medical X-ray imaging phantom prototype.
Abstract Diagnostic X-ray imaging depends on the maintenance of image quality that allows for proper diagnosis of medical conditions. Maintenance of image quality requires quality assurance programs on the various X-ray modalities, which consist of pro-jection radiography (including mobile X-ray units), fluoroscopy, mammography, and computed tomography (CT) scanning. Currently a variety of modality-specific phantoms are used to perform quality assurance (QA) tests. These phantoms are not only expensive, but suitably trained personnel are needed to successfully use them and interpret the results. The question arose...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Groenewald A, Groenewald WA Tags: J Appl Clin Med Phys Source Type: research

Comparison of the low contrast detectability of two ultrasound systems using a greyscale phantom.
ring;th M Abstract The purpose of the present study was to evaluate the relevance of using a phantom to simulate a clinical situation where small low contrast objects are embedded in relatively homogeneous organs in order to discriminate between different ultrasound machines, taking into account human observer variability. One high-end and one general ultrasound machine using the same probe were included. Images containing 4 and 6.4-mm objects of four different contrasts were collected from a greyscale phantom at different depths. Six observers participated in a 4-alternative forced choice study based on 960 image...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Lorentsson R, Hosseini N, Johansson JO, Rosenberg W, Stenborg B, Månsson LG, Båth M Tags: J Appl Clin Med Phys Source Type: research

Deriving detector-specific correction factors for rectangular small fields using a scintillator detector.
Abstract The goal of this study was to investigate small field output factors (OFs) for flat-tening filter-free (FFF) beams on a dedicated stereotactic linear accelerator-based system. From this data, the collimator exchange effect was quantified, and detector-specific correction factors were generated. Output factors for 16 jaw-collimated small fields (from 0.5 to 2 cm) were measured using five different detectors including an ion chamber (CC01), a stereotactic field diode (SFD), a diode detector (Edge), Gafchromic film (EBT3), and a plastic scintillator detector (PSD, W1). Chamber, diodes, and PSD measurements w...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Qin Y, Zhong H, Wen N, Snyder K, Huang Y, Chetty IJ Tags: J Appl Clin Med Phys Source Type: research

Evaluation of dose-area product of common radiographic examinations towards establishing a preliminary diagnostic reference levels (PDRLs) in Southwestern Nigeria.
Abstract In Nigeria, a large number of radiographic examinations are conducted yearly for various diagnostic purposes. However, most examinations carried out do not have records of doses received by the patients, and the employed exposure parameters used are not documented; therefore, adequate radiation dose management is hin-dered. The aim of the present study was to estimate the dose-area product (DAP) of patients examined in Nigeria, and to propose regional reference dose levels for nine common examinations (chest PA, abdomen AP, pelvis AP, lumbar AP, skull AP, leg AP, knee AP, hand AP, and thigh AP) undertaken...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Jibiri NN, Olowookere CJ Tags: J Appl Clin Med Phys Source Type: research

A survey on table tolerances and couch overrides in radiotherapy.
Abstract The purpose of this study was to survey current departmental policies on treatment couch overrides and the values of table tolerances used clinically. A 25-question electronic survey on couch overrides and tolerances was sent to full members of the American Association of Physicists in Medicine (AAPM). The first part of the survey asked participants if table overrides were allowed at their institution, who was allowed to perform these overrides, and if imaging was required with overrides. The second part of the survey asked individuals to provide table tolerance data for the following treatment sites: bra...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Chinsky B, Patel R, Panfil J, Surucu M, Roeske JC Tags: J Appl Clin Med Phys Source Type: research

Accuracy of automatic matching of Catphan 504 phantom in cone-beam computed tomography for tube current-exposure time product.
Abstract The purpose of this study is to evaluate the accuracy of automatic matching in cone-beam computed tomography (CBCT) images relative to the reduction of total tube current-exposure time product (mAs) for the X-ray imaging (XI) system. The CBCT images were acquired with the Catphan 504 phantom various total mAs ratios such as 1.00, 0.83, 0.67, 0.57, and 0.50. For studying the automatic match-ing accuracy, the phantom images were acquired with a six-dimensional shifting table. The image quality and correction of automatic matching were compared. With a decreasing total mAs ratio, the noise of the images incr...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Won HS, Chung JB, Choi BD, Park JH, Hwang DG Tags: J Appl Clin Med Phys Source Type: research

Evaluation of kidney motion and target localization in abdominal SBRT patients.
Abstract The purpose of this study was to evaluate bilateral kidney and target translational/rotational intrafraction motion during stereotactic body radiation therapy treatment delivery of primary renal cell carcinoma and oligometastatic adrenal lesions for patients immobilized in the Elekta BodyFIX system. Bilateral kidney motion was assessed at midplane for 30 patients immobilized in a full-body dual-vacuum-cushion system with two patients immobilized via abdominal compression. Intrafraction motion was assessed for 15 patients using kilovoltage cone-beam computed tomography (kV-CBCT) datasets (n = 151) correlat...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Sonier M, Chu W, Lalani N, Erler D, Cheung P, Korol R Tags: J Appl Clin Med Phys Source Type: research

An innovative method to acquire the location of point A for cervical cancer treatment by HDR brachytherapy.
Abstract Brachytherapy of local cervical cancer is generally accomplished through film-based treatment planning with the prescription directed to point A, which is invisible on images and is located at a high-dose gradient area. Through a standard reconstruction method by digitizing film points, the location error for point A would be 3mm with a condition of 30° curvature tandem, which is 10° away from the gantry rotation axis of a simulator, and has an 8.7 cm interval between the flange and the isocenter. To reduce the location error of the reconstructed point A, this paper proposes a method and demonstra...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Chang L, Ho SY, Yeh SA, Lee TF, Chen PY Tags: J Appl Clin Med Phys Source Type: research

The feasibility of using Microsoft Kinect v2 sensors during radiotherapy delivery.
Abstract Consumer-grade distance sensors, such as the Microsoft Kinect devices (v1 and v2), have been investigated for use as marker-free motion monitoring systems for radiotherapy. The radiotherapy delivery environment is challenging for such sen-sors because of the proximity to electromagnetic interference (EMI) from the pulse forming network which fires the magnetron and electron gun of a linear accelerator (linac) during radiation delivery, as well as the requirement to operate them from the control area. This work investigated whether using Kinect v2 sensors as motion monitors was feasible during radiation de...
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Edmunds DM, Bashforth SE, Tahavori F, Wells K, Donovan EM Tags: J Appl Clin Med Phys Source Type: research

Implementation of quality medical physics training in a low-middle income country - sharing experience from a tertiary care JCIA-accredited university hospital.
PMID: 27929517 [PubMed - in process] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Abbasi AN, Muhammad W, Hussain A Tags: J Appl Clin Med Phys Source Type: research

The Diagnosis of Prostate Cancer.
PMID: 27929518 [PubMed - in process] (Source: Journal of Applied Clinical Medical Physics)
Source: Journal of Applied Clinical Medical Physics - November 8, 2016 Category: Physics Authors: Schulz RJ Tags: J Appl Clin Med Phys Source Type: research

Radiation leakage dose from Elekta electron collimation system.
This study provided baseline data required for a greater project, whose objective was to design a new Elekta electron collimation system having significantly lighter electron applicators with equally low out-of field leakage dose. Specifically, off-axis dose profiles for the electron collimation system of our uniquely configured Elekta Infinity accelerator with the MLCi2 treatment head were measured and calculated for two primary purposes: 1) to evaluate and document the out-of-field leakage dose in the patient plane and 2) to validate the dose distributions calculated using a BEAMnrc Monte Carlo (MC) model for out-of-fiel...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Pitcher GM, Hogstrom KR, Carver RL Tags: J Appl Clin Med Phys Source Type: research

Evaluation of cassette-based digital radiography detectors using standardized image quality metrics: AAPM TG-150 Draft Image Detector Tests.
This study evaluated the effects of ROI size and layout on the image metrics by using four different ROI sets, assessed result uncertainty by repeating measurements, and compared results with two commercially available quality control tools, namely the Carestream DIRECTVIEW Total Quality Tool (TQT) and the GE Healthcare Quality Assurance Process (QAP). Seven Carestream DRX-1C (CsI) detectors on mobile DR systems and four GE FlashPad detectors in radiographic rooms were tested. Images were analyzed using MATLAB software that had been previously validated and reported. Our values for signal and SNR nonuniformity and MTF agre...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Li G, Greene TC, Nishino TK, Willis CE Tags: J Appl Clin Med Phys Source Type: research

Surface imaging, laser positioning or volumetric imaging for breast cancer with nodal involvement treated by helical TomoTherapy.
gau E Abstract A surface imaging system, Catalyst (C-Rad), was compared with laser-based positioning and daily mega voltage computed tomography (MVCT) setup for breast patients with nodal involvement treated by helical TomoTherapy. Catalyst-based positioning performed better than laser-based positioning. The respective modalities resulted in a standard deviation (SD), 68% confidence interval (CI) of positioning of left-right, craniocaudal, anterior-posterior, roll: 2.4 mm, 2.7 mm, 2.4 mm, 0.9° for Catalyst positioning, and 6.1 mm, 3.8 mm, 4.9 mm, 1.1° for laser-based positioning, respectively. MVCT-based p...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Crop F, Pasquier D, Baczkiewic A, Doré J, Bequet L, Steux E, Gadroy A, Bouillon J, Florence C, Muszynski L, Lacour M, Lartigau E Tags: J Appl Clin Med Phys Source Type: research

Secondary cancer-incidence risk estimates for external radiotherapy and high-dose-rate brachytherapy in cervical cancer: phantom study.
This study was designed to estimate radiation-induced secondary cancer risks from high-dose-rate (HDR) brachytherapy and external radiotherapy for patients with cervical cancer based on measurements of doses absorbed by various organs. Organ doses from HDR brachytherapy and external radiotherapy were measured using glass rod dosimeters. Doses to out-of-field organs were measured at various loca-tions inside an anthropomorphic phantom. Brachytherapy-associated organ doses were measured using a specialized phantom that enabled applicator insertion, with the pelvis portion of the existing anthropomorphic phantom replaced by t...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Lee B, Ahn SH, Kim H, Son J, Sung J, Han Y, Huh SJ, Kim JS, Kim DW, Yoon M Tags: J Appl Clin Med Phys Source Type: research

Characteristics of quantitative perfusion parameters on dynamic contrast-enhanced MRI in mammographically occult breast cancer.
Abstract The purpose of this study was to compare the characteristics of quantitative per-fusion parameters obtained from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in patients with mammographically occult (MO) breast cancers and those with mammographically visible (MV) breast cancers. Quantitative parameters (AUC, Ktrans, kep, ve, vp, and wi) from 13 MO breast cancers and 16 MV breast cancers were mapped after the DCE-MRI data were acquired. Various prog-nostic factors, including axillary nodal status, estrogen receptor (ER), progesterone receptor (PR), Ki-67, p53, E-cadherin, and human epid...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Ryu JK, Rhee SJ, Song JY, Cho SH, Jahng GH Tags: J Appl Clin Med Phys Source Type: research

Is the dose distribution distorted in IMRT and RapidArc treatment when patient plans are swapped across beam-matched machines?
Abstract The purpose of this study is to evaluate the degree of dose distribution distortion in advanced treatments like IMRT and RapidArc when patient plans are swapped across dosimetrically equivalent so-called "beam-matched" machines. For this purpose the entire work is divided into two stages. At forefront stage all basic beam properties of 6 MV X-rays like PDD, profiles, output factors, TPR20/10 and MLC transmission of two beam-matched machines - Varian Clinac iX and Varian 600 C/D Unique - are compared and evaluated for differences. At second stage 40 IMRT and RapidArc patient plans from the pool o...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Chockkalingam K, Radha CA, Subramani V, Subramani V, Gunasekaran MK Tags: J Appl Clin Med Phys Source Type: research

Initial clinical experience with ArcCHECK for IMRT/VMAT QA.
Abstract Many devices designed for the purpose of performing patient-specific IMRT/VMAT QA are commercially available. In this work we report our experience and initial clinical results with the ArcCHECK. The ArcCHECK consists of a cylindrical array of diode detectors measuring entry and exit doses. The measured result is a cumulative dose displayed as a 2D matrix. The detector array requires both an absolute dose calibration, and a calibration of the detector response, relative to each other. In addition to the calibrations suggested by the manufacturer, various tests were performed in order to assess its stabili...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Aristophanous M, Suh Y, Chi PC, Whittlesey LJ, LaNeave S, Martel MK Tags: J Appl Clin Med Phys Source Type: research

Simultaneously integrated boost (SIB) spares OAR and reduces treatment time in locally advanced cervical cancer.
Abstract We performed a dosimetric comparison of sequential IMRT (sIMRT) and simul-taneously integrated boost (SIB) IMRT to boost PET-avid lymph nodes while concurrently treating pelvic targets to determine the potential of SIB IMRT to reduce overall treatment duration in locally advanced cervical cancer. Ten patients receiving definitive radiation therapy were identified retrospectively. RTOG consensus guidelines were followed to delineate the clinical target volume and organs at risk (OAR), which were then expanded per IMRT consortium guidelines to yield the planning target volume (PTV). Dosimetric parameters fo...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Feng CH, Hasan Y, Kopec M, Al-Hallaq HA Tags: J Appl Clin Med Phys Source Type: research

Revisiting fetal dose during radiation therapy: evaluating treatment techniques and a custom shield.
Abstract To create a comprehensive dataset of peripheral dose (PD) measurements from a new generation of linear accelerators with and without the presence of a newly designed fetal shield, PD measurements were performed to evaluate the effects of depth, field size, distance from the field edge, collimator angle, and beam modi-fiers for common treatment protocols and modalities. A custom fetal lead shield was designed and made for our department that allows external beam treatments from multiple angles while minimizing the need to adjust the shield during patient treatments. PD measurements were acquired for a comp...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Owrangi AM, Roberts DA, Covington EL, Hayman JA, Masi KM, Lee C, Moran JM, Prisciandaro JI Tags: J Appl Clin Med Phys Source Type: research

Translucent poly(vinyl alcohol) cryogel dosimeters for simultaneous dose buildup and monitoring during chest wall radiation therapy.
Abstract Chest wall radiation therapy treatment delivery was monitored using a 5 mm thick radiochromic poly(vinyl alcohol) cryogel that also provided buildup material. The cryogels were used to detect positioning errors and measure the impact of shifts for a chest wall treatment that was delivered to a RANDO phantom. The phantom was shifted by ± 2, ± 3, and ± 5 mm from the planned position in the anterior/posterior (A/P) direction; these shifts represent setup errors and the uncertainty associated with lung filling during breath-hold. The two-dimensional absolute dose distributions measured in...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Eyadeh MM, Weston MA, Juhasz J, Diamond KR Tags: J Appl Clin Med Phys Source Type: research

Verification measurements of an eMC algorithm using a 2D ion chamber array.
Abstract The aim of this study was to assess the suitability of the Im'RT MatriXX 2D ion chamber array for performing verification measurements on the Varian Eclipse electron Monte Carlo (eMC) algorithm for a range of clinical energies (6, 12, and 20 MeV) on a Varian 2100iX linear accelerator. Firstly, the suitability of the MatriXX for measuring percentage depth doses (PDD) in water was assessed, including characterization of the inherent buildup found in the MatriXX. Secondly the suitability of the MatriXX for measuring dose distributions in homogeneous and heterogeneous phantoms was assessed using gamma analysis ...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Wanklyn MD, Kidane G, Crees L Tags: J Appl Clin Med Phys Source Type: research

Implementation and evaluation of a protocol management system for automated review of CT protocols.
This article describes our experiences in the implementation and evaluation of this protocol monitoring system. In particular, we discuss various strategies for addressing each of the steps in our protocol-monitoring workflow, which are: maintaining an accurate set of master protocols, retrieving protocols from the scanners, comparing scanner protocols to master protocols, reviewing flagged differences between the scanner and master protocols, and updating the scanner and/or master protocols. In our initial evaluation focusing only on abdo-men and pelvis protocols, we detected 309 modified protocols in a 24-week trial peri...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Grimes J, Leng S, Zhang Y, Vrieze T, McCollough C Tags: J Appl Clin Med Phys Source Type: research

Dosimetric impact of cylinder size in high-dose rate vaginal cuff brachytherapy (VCBT) for primary endometrial cancer.
Abstract The purpose of this study was to evaluate the dosimetric impact of cylinder size in high-dose-rate (HDR) vaginal cuff brachytherapy (VCBT). Sample plans of HDR VCBT in a list of cylinders ranging from 2.5 to 4 cm in diameter at 0.5 cm incre-ment were created and analyzed. The doses were prescribed either at the 0.5cm depth with 5.5 Gy for 4 fractions or at the cylinder surface with 8.8 Gy for 4 frac-tions, in various treatment lengths. A 0.5 cm shell volume called PTV_Eval was contoured for each plan and served as the target volume for dosimetric evaluation. The cumulative and differential dose volume his...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Zhang H, Gopalakrishnan M, Lee P, Kang Z, Sathiaseelan V Tags: J Appl Clin Med Phys Source Type: research

On the use of a convolution-superposition algorithm for plan checking in lung stereotactic body radiation therapy.
Abstract Stereotactic body radiation therapy (SBRT) aims to deliver a highly conformal ablative dose to a small target. Dosimetric verification of SBRT for lung tumors presents a challenge due to heterogeneities, moving targets, and small fields. Recent software (M3D) designed for dosimetric verification of lung SBRT treatment plans using an advanced convolution-superposition algorithm was evaluated. Ten lung SBRT patients covering a range of tumor volumes were selected. 3D CRT plans were created using the XiO treatment planning system (TPS) with the superposition algorithm. Dose was recalculated in the Eclipse TP...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Hardcastle N, Oborn BM, Haworth A Tags: J Appl Clin Med Phys Source Type: research

Diode-based transmission detector for IMRT delivery monitoring: a validation study.
Abstract The purpose of this work was to evaluate the potential of a new transmission detector for real-time quality assurance of dynamic-MLC-based radiotherapy. The accuracy of detecting dose variation and static/dynamic MLC position deviations was measured, as well as the impact of the device on the radiation field (surface dose, transmission). Measured dose variations agreed with the known variations within 0.3%. The measurement of static and dynamic MLC position deviations matched the known deviations with high accuracy (0.7-1.2 mm). The absorption of the device was minimal (~ 1%). The increased surface dose w...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Li T, Wu QJ, Matzen T, Yin FF, O'Daniel JC Tags: J Appl Clin Med Phys Source Type: research

Technical Note: A respiratory monitoring and processing system based on computer vision: prototype and proof of principle.
Abstract Monitoring and controlling respiratory motion is a challenge for the accuracy and safety of therapeutic irradiation of thoracic tumors. Various commercial systems based on the monitoring of internal or external surrogates have been developed but remain costly. In this article we describe and validate Madibreast, an in-house-made respiratory monitoring and processing device based on optical tracking of external markers. We designed an optical apparatus to ensure real-time submillimetric image resolution at 4 m. Using OpenCv libraries, we optically tracked high-contrast markers set on patients' breasts. Val...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Leduc N, Atallah V, Escarmant P, Vinh-Hung V Tags: J Appl Clin Med Phys Source Type: research

Investigation on using high-energy proton beam for total body irradiation (TBI).
Abstract This work investigated the possibility of using proton beam for total body irradia-tion (TBI). We hypothesized the broad-slow-rising entrance dose from a monoen-ergetic proton beam can deliver a uniform dose to patient with varied thickness. Comparing to photon-based TBI, it would not require any patient-specific com-pensator or beam spoiler. The hypothesis was first tested by simulating 250 MeV, 275 MeV, and 300 MeV protons irradiating a wedge-shaped water phantom in a paired opposing arrangement using Monte Carlo (MC) method. To allow ± 7.5% dose variation, the maximum water equivalent thickness ...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Zhang M, Qin N, Jia X, Zou WJ, Khan A, Yue NJ Tags: J Appl Clin Med Phys Source Type: research

A noise power spectrum study of a new model-based iterative reconstruction system: Veo 3.0.
Abstract The purpose of this study was to evaluate performance of the third generation of model-based iterative reconstruction (MBIR) system, Veo 3.0, based on noise power spectrum (NPS) analysis with various clinical presets over a wide range of clinically applicable dose levels. A CatPhan 600 surrounded by an oval, fat-equivalent ring to mimic patient size/shape was scanned 10 times at each of six dose levels on a GE HD 750 scanner. NPS analysis was performed on images reconstructed with various Veo 3.0 preset combinations for comparisons of those images reconstructed using Veo 2.0, filtered back projection (FBP...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Li G, Liu X, Dodge CT, Jensen CT, Rong XJ Tags: J Appl Clin Med Phys Source Type: research

MRI quantification of pancreas motion as a function of patient setup for particle therapy -a preliminary study.
Abstract Particle therapy (PT) has shown positive therapeutic results in local control of locally advanced pancreatic lesions. PT effectiveness is highly influenced by target localization accuracy both in space, since the pancreas is located in proximity to radiosensitive vital organs, and in time as it is subject to substantial breathing-related motion. The purpose of this preliminary study was to quantify pancreas range of motion under typical PT treatment conditions. Three common immobilization devices (vacuum cushion, thermoplastic mask, and compressor belt) were evaluated on five male patients in prone and su...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Fontana G, Riboldi M, Gianoli C, Chirvase CI, Villa G, Paganelli C, Summers PE, Tagaste B, Pella A, Fossati P, Ciocca M, Baroni G, Valvo F, Orecchia R Tags: J Appl Clin Med Phys Source Type: research

Patient-specific 17-segment myocardial modeling on a bull's eye map.
Abstract The purpose of this study was to develop and validate cardiac computed tomog-raphy (CT) quantitative analysis software with a patient-specific, 17-segment myocardial model that uses electrocardiogram (ECG)-gated cardiac CT images to differentiate between normal controls and severe aortic stenosis (AS) patients. ECG-gated cardiac CT images from 35 normal controls and 144 AS patients were semiautomatically segmented to create a patient-specific, 17-segment myocardial model. Two experts then manually determined the anterior and posterior interven-tricular grooves to be boundaries between the 1st and 2nd segm...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Jung J, Kim YH, Kim N, Yang DH Tags: J Appl Clin Med Phys Source Type: research

MRI geometric distortion: Impact on tangential whole-breast IMRT.
Abstract The purpose of this study was to determine the impact of magnetic resonance imaging (MRI) geometric distortions when using MRI for target delineation and planning for whole-breast, intensity-modulated radiotherapy (IMRT). Residual system distortions and combined systematic and patient-induced distortions are considered. This retrospective study investigated 18 patients who underwent whole-breast external beam radiotherapy, where both CT and MRIs were acquired for treatment planning. Distortion phantoms were imaged on two MRI systems, dedicated to radiotherapy planning (a wide, closed-bore 3T and an open-b...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Walker A, Metcalfe P, Liney G, Batumalai V, Dundas K, Glide-Hurst C, Delaney GP, Boxer M, Yap ML, Dowling J, Rivest-Henault D, Pogson E, Holloway L Tags: J Appl Clin Med Phys Source Type: research

A comparative study of identical VMAT plans with and without jaw tracking technique.
Abstract The unwanted radiation transmission through the multileaf collimators could be reduced by the jaw tracking technique which is commercially available on Varian TrueBeam accelerators. On the basis of identical plans, this study aims to investigate the dosimetric impact of jaw tracking on the volumetric-modulated arc therapy (VMAT) plans. Using Eclipse treatment planning system (TPS), 40 jaw-tracking VMAT plans with various tumor volumes and shapes were optimized. Fixed jaw plans were created by editing the jaw coordinates of the jaw-tracking plans while other parameters were identical. The deliverability of...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Wu H, Jiang F, Yue H, Hu Q, Zhang J, Liu Z, Gong J, Li S, Geng J, Zhang Y Tags: J Appl Clin Med Phys Source Type: research

Clinical experience with planning, quality assurance, and delivery of burst-mode modulated arc therapy.
We present our clinical experience with the planning techniques and plan quality assurance measurements of mARC delivery. Clinical mARC plans for five representative cases (prostate, low-dose-rate brain, brain with partial-arc vertex fields, pancreas, and liver SBRT) were generated using a Monte Carlo-based treatment planning system. A conventional-dose-rate flat 6 MV and a high-dose-rate non-flat 7 MV beam are available for planning and delivery. mARC plans for intact-prostate cases can typically be created using one 360° arc, and treatment times per fraction seldom exceed 6 min using the flat beam; using the nonflat ...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Kainz K, Prah D, Ahunbay E, Li XA Tags: J Appl Clin Med Phys Source Type: research

Dosimetric comparison between cone/Iris-based and InCise MLC-based CyberKnife plans for single and multiple brain metastases.
Abstract We performed an evaluation of the CyberKnife InCise MLC by comparing plan qualities for single and multiple brain lesions generated using the first version of InCise MLC, fixed cone, and Iris collimators. We also investigated differences in delivery efficiency among the three collimators. Twenty-four patients with single or multiple brain mets treated previously in our clinic on a CyberKnife M6 using cone/Iris collimators were selected for this study. Treatment plans were generated for all lesions using the InCise MLC. Number of monitor units, delivery time, target coverage, conformity index, and dose fal...
Source: Journal of Applied Clinical Medical Physics - September 30, 2016 Category: Physics Authors: Jang SY, Lalonde R, Ozhasoglu C, Burton S, Heron D, Huq MS Tags: J Appl Clin Med Phys Source Type: research