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Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists

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https://www.readbyqxmd.com/read/28886961/a-feasibility-study-of-using-advanced-external-beam-techniques-to-create-a-vaginal-cuff-brachytherapy-like-endometrial-boost-plan
#1
Zachary Grelewicz, Brooke Zerrusen, Vythialingam Sathiaseelan, Hualin Zhang
The purpose of this study was to explore the feasibility of using advanced external beam radiation therapy (EBRT) planning techniques for creating plans that could be used as a possible alternative for high-dose rate (HDR) vaginal cuff brachytherapy (VCBT) boost in treating endometrial cancer. The computed tomography (CT) images of a total of 4 female patients who had endometrial cancer treated with HDR-VCBT were selected for this study. A typical HDR-VCBT target volume, 0.5-cm-thick shell volume around the cylinder applicator in the prescribed treatment length was contoured and used as the planning target volume (PTV) in both the HDR VCBT and the EBRT VCBT-like plans...
September 5, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28870525/rectal-balloon-use-limits-vaginal-displacement-rectal-dose-and-rectal-toxicity-in-patients-receiving-imrt-for-postoperative-gynecological-malignancies
#2
Cheng-Chia Wu, Yen-Ruh Wuu, Theodore Yanagihara, Ashish Jani, Eric P Xanthopoulos, Akhil Tiwari, Jason D Wright, William M Burke, June Y Hou, Ana I Tergas, Israel Deutsch
Pelvic radiotherapy for gynecologic malignancies traditionally used a 4-field box technique. Later trials have shown the feasibility of using intensity-modulated radiotherapy (IMRT) instead. But vaginal movement between fractions is concerning when using IMRT due to greater conformality of the isodose curves to the target and the resulting possibility of missing the target while the vagina is displaced. In this study, we showed that the use of a rectal balloon during treatment can decrease vaginal displacement, limit rectal dose, and limit acute and late toxicities...
September 1, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28867367/clinical-analysis-of-the-approximate-3-dimensional-biological-effective-dose-equation-in-multiphase-treatment-plans
#3
Kevin I Kauweloa, Alonso N Gutierrez, Angelo M Bergamo, Sotirios Stathakis, Nikos Papanikolaou, Panayiotis Mavroidis
A multiphase, approximate biological effective dose (BEDA) equation was introduced because most treatment planning systems (TPS) are incapable of calculating the true BED (BEDT). This work investigates the accuracy and precision of the multiphase BEDA relative to the BEDT in clinical cases. Ten patients with head and neck cancer and 10 patients with prostate cancer were studied using their treatment plans from Pinnacle(3) 9.2 (Philips Medical, Fitchburg, WI). The organs at risk (OARs) that were studied are the normal brain, left and right optic nerves, optic chiasm, spinal cord, brainstem, bladder, and rectum...
August 31, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28843380/the-impact-of-intensity-modulated-radiation-therapy-plan-normalization-in-the-postprostatectomy-setting-does-it-matter
#4
Mary Anne Stritch, Elizabeth Forde, Michelle Leech
The International Commission on Radiation Units & Measurements -83 recommends prescribing intensity-modulated radiation therapy (IMRT) in a dose-volume manner. Despite this, clinical variation still exists in how prostate IMRT plans are prescribed. This study aims to investigate the impact of different plan normalization methods for postprostatectomy IMRT. IMRT treatment plans were created retrospectively for 20 postprostatectomy patients. These were normalized such that the dose received by 98% (D98) of the planning target volume (PTV) was equal to 100% of the prescribed dose...
August 23, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28822604/volumetric-modulated-arc-therapy-vmat-for-whole-brain-radiotherapy-not-only-for-hippocampal-sparing-but-also-for-reduction-of-dose-to-organs-at-risk
#5
Sumit Sood, Damodar Pokhrel, Christopher McClinton, Christopher Lominska, Rajeev Badkul, Hongyu Jiang, Fen Wang
A prospective clinical trial, Radiation Therapy Oncology Group (RTOG) 0933, has demonstrated that whole brain radiotherapy (WBRT) using conformal radiation delivery technique with hippocampal avoidance is associated with less memory complications. Further sparing of other organs at risk (OARs) including the scalp, ear canals, cochleae, and parotid glands could be associated with reductions in additional toxicities for patients treated with WBRT. We investigated the feasibility of WBRT using volumetric-modulated arc therapy (VMAT) to spare the hippocampi and the aforementioned OARs...
August 16, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28818321/influence-of-computed-tomography-contrast-agent-on-radiotherapy-dose-calculation-for-pancreatic-carcinoma-a-dosimetric-study-based-on-tomotherapy-and-volumetric-modulated-arc-therapy-techniques
#6
Feng Zhu, Weizhang Wu, Fuhai Zhu, Yong Wang, Yingjie Wang, Tingyi Xia
The main purpose of our investigation was to quantify the dosimetric influence of intravenous contrast agent for pancreatic cancer radiotherapy treatment. This study focused on complex modulated irradiation techniques of tomotherapy (TOMO) and volumetric-modulated arc therapy (VMAT) to investigate if novel conformal treatment methods could reduce the influence of contrast agent. In our study, patients with pancreatic cancer were enrolled to have 2 computed tomography (CT) scans in the same position without and with intravenous contrast agent for treatment planning...
August 14, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28802976/prognostic-factors-associated-with-the-accuracy-of-deformable-image-registration-in-lung-cancer-patients-treated-with-stereotactic-body-radiotherapy
#7
Yasuharu Sugawara, Hidenobu Tachibana, Noriyuki Kadoya, Nozomi Kitamura, Amit Sawant, Keiichi Jingu
We evaluated the accuracy of an in-house program in lung stereotactic body radiation therapy (SBRT) cancer patients, and explored the prognostic factors associated with the accuracy of deformable image registrations (DIRs). The accuracy of the 3 programs which implement the free-form deformation and the B-spline algorithm was compared regarding the structures on 4-dimensional computed tomography (4DCT) image datasets between the peak-inhale and peak-exhale phases. The dice similarity coefficient (DSC) and normalized DSC (NDSC) were measured for the gross tumor volumes from 19 lung SBRT patients...
August 9, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28797720/multi-isocenter-hybrid-electron-and-rapid-arc-photon-treatment-for-reirradiation-of-extensive-recurrent-inflammatory-breast-cancer
#8
Ryan S Youland, Randi R Finley, Ivy A Petersen, Kimberly S Corbin
Delivering an adequate and homogenous dose to a large volume of recurrent cutaneous disease can be challenging even with modern techniques. Here, the authors describe a 3-isocenter hybrid electron and rapid arc photon radiation treatment plan to provide optimal tumor coverage to an extensive recurrence of inflammatory breast carcinoma. This approach allowed for homogeneous treatment of a large volume while effectively modulating dose to previously irradiated tissue and minimizing dose to the underlying heart, lungs and brachial plexus...
August 7, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28797719/influence-of-tumor-location-on-the-intensity-modulated-radiation-therapy-plan-of-helical-tomotherapy
#9
Yingjie Xu, Hui Yan, Zhihui Hu, Pan Ma, Kuo Men, Peng Huang, Wenting Ren, Jianrong Dai, Yexiong Li
Given the design of the Helical TomoTherapy device, the patient's central axis is routinely aligned with the machine's rotational axis to prevent the patient's body from colliding with the machine walls. However, for treatment of tumors located away from the patient's central axis, this position may not be optimal as the adequate radiation dose may not reach the affected site. Our study aimed to investigate the influence of tumor location on dose quality and delivery efficiency of tomotherapy plans. A phantom and 15 patients were selected for this study...
August 7, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28784431/improving-plan-quality-for-prostate-volumetric-modulated-arc-therapy
#10
Katrina Wright, Janet Ferrari-Anderson, Tamara Barry, Anne Bernard, Elizabeth Brown, Margot Lehman, David Pryor
We critically evaluated the quality and consistency of volumetric-modulated arc therapy (VMAT) prostate planning at a single institution to quantify objective measures for plan quality and establish clear guidelines for plan evaluation and quality assurance. A retrospective analysis was conducted on 34 plans generated on the Pinnacle(3) version 9.4 and 9.8 treatment planning system to deliver 78 Gy in 39 fractions to the prostate only using VMAT. Data were collected on contoured structure volumes, overlaps and expansions, planning target volume (PTV) and organs at risk volumes and relationship, dose volume histogram, plan conformity, plan homogeneity, low-dose wash, and beam parameters...
August 4, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28784430/risk-of-dry-eye-syndrome-in-patients-treated-with-whole-brain-radiotherapy
#11
Tavish Nanda, Cheng-Chia Wu, Ashley A Campbell, Ryan M Bathras, Ashish Jani, Michael Kazim, Tony J Wang
With improvements in systemic therapy, patients with cancer treated with whole-brain radiotherapy (WBRT) are living long enough to develop late toxicities, including dry eye syndrome. In general practice, dose to the lacrimal gland (LG) is not constrained (maximum constraint <40 Gy) in WBRT. The purpose of this study was to measure dose to the LG in WBRT and determine methods for reducing radiation exposure. We conducted a retrospective review of 70 3-dimensional (3D) conformal plans; thirty-six plans with a radiation prescription of 30 Gy in 10 fractions and 34 plans with a prescription of 37...
August 4, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28781156/evaluation-of-deformed-image-based-dose-calculations-for-adaptive-radiotherapy-of-nasopharyngeal-carcinoma
#12
Miranda Poon, Catherine Holborn, Ka Fai Cheng, Winky Wing Ki Fung, George Chiu
The ultimate goal of adaptive radiotherapy (ART) is to deliver truly customized radiation treatments. Currently, the quality of cone-beam computed tomography (CBCT) images is still inferior to that of conventional CT images in contour delineations and dose calculations for replanning purposes. This retrospective study aims to evaluate the dosimetric accuracy of using deformed conventional CT images for dose calculations, in the hope of inferring the feasibility of ART using planning CT (PCT) images that deformed to up-to-date CBCT images for patients with nasopharyngeal carcinoma (NPC)...
August 3, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28774760/dosimetric-comparison-of-rectal-sparing-capabilities-of-rectal-balloon-vs-injectable-spacer-gel-in-stereotactic-body-radiation-therapy-for-prostate-cancer-lessons-learned-from-prospective-trials
#13
Ryan T Jones, Nima Hassan Rezaeian, Neil B Desai, Yair Lotan, Xun Jia, Raquibul Hannan, D W Nathan Kim, Brad Hornberger, Jeffrey Dubas, Aaron M Laine, Michael J Zelefsky, Robert D Timmerman, Michael R Folkert
This study aimed to compare the rectal-sparing capabilities of rectal balloons vs absorbable injectable spacer gel in stereotactic body radiation therapy (SBRT) for prostate cancer. Patient samples included in this analysis were obtained from 2 multi-institutional prospective trials of SBRT for prostate cancer using a rectal balloon (n = 36 patients) and injectable spacer gel (n = 36). Treatment prescription dose was 45 Gy in 5 fractions in 42 patients; for equal comparison, the remaining 30 patients were rescaled to 45 Gy from 47...
July 31, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28760560/hippocampal-dose-from-stereotactic-radiosurgery-for-4-to-10-brain-metastases-risk-factors-feasibility-of-dose-reduction-via-re-optimization-and-patient-outcomes
#14
Samuel R Birer, Adam C Olson, Justus Adamson, Rodney Hood, Matthew Susen, Grace Kim, Joseph K Salama, John P Kirkpatrick
This study aimed to report hippocampal dose from single-fraction stereotactic radiosurgery (SRS) for 4 to 10 brain metastases and determine feasibility of hippocampal-sparing SRS. Patients with 4 to 10 brain metastases receiving single-isocenter, multi-target single-fraction SRS were identified. Hippocampi were contoured using the Radiation Therapy Oncology Group (RTOG) 0933 atlas. RTOG 0933 dose constraints were converted to a biologically effective dose using an alpha/beta of 2 (D100 421 cGy, Dmax 665 cGy)...
July 28, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28754289/dosimetric-benefits-of-automation-in-the-treatment-of-lower-thoracic-esophageal-cancer-is-manual-planning-still-an-alternative-option
#15
Xiadong Li, Lu Wang, Jiahao Wang, Xu Han, Bing Xia, Shixiu Wu, Weigang Hu
This study aimed to design automated volumetric-modulated arc therapy (VMAT) plans in Pinnacle auto-planning and compare it with manual plans for patients with lower thoracic esophageal cancer (EC). Thirty patients with lower thoracic EC were randomly selected for replanning VMAT plans using auto-planning in Pinnacle treatment planning system (TPS) version 9.10. Historical plans of these patients were then compared. Dose-volume histogram (DVH) statistics, dose uniformity, and dose homogeneity were analyzed to evaluate treatment plans...
July 25, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28739211/investigating-the-surface-dose-contribution-of-intrafractional-kv-imaging-in-cyberknife-based-stereotactic-radiosurgery
#16
Abdulmecit Canbolat, Faruk Zorlu, Pervin Hurmuz, Mete Yeginer, Gokhan Ozyigit
CyberKnife treatment consists of hundreds of noncoplanar beams and numerous intrafractional images that can be taken during a single treatment fraction; thus, doses because of imaging should be considered in this technique. The aim of this study is to investigate the in-field and out-of-field surface doses induced from kV imaging system during stereotactic radiosurgery (SRS) treatment. The imaging-induced surface doses were measured at the center of the imaging field and within ±15-cm distance from the center in both craniocaudal and lateral directions...
July 21, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28735836/importance-of-deformable-image-registration-and-biological-dose-summation-in-planning-of-radiotherapy-retreatments
#17
Eeva Boman, Mika Kapanen, Lyndsey Pickup, Sirpa-Liisa Lahtela
The purpose of this study is to evaluate the effect of nonrigid and fractionation-corrected dose summation on total doses in radiotherapy and to demonstrate the benefits of such dose summation on clinical decision-making for planning of retreatments. Dose summation of organs at risk (OARs) was investigated for 3 clinical cases with need of retreatment to the same site: head and neck, brain, and mediastinum. Three different summation methods over old and new radiotherapy treatment plans are presented and compared: (1) rigid raw sum with rigid registration of the planning images and direct dose summing; (2) deformable raw sum with deformable image registration and direct dose summing; and (3) deformable biological sum with deformable registration and takes into account the dose per fraction in biological manner in certain critical organs...
July 20, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28733115/dose-distribution-characteristic-study-of-the-rotating-gamma-knife-rgk-by-using-the-geometry-analytic-method
#18
Fen Chen, Jun-Wen Shi, Zhao-Sheng Yin, Ying Peng, Yee-Min Jen, Jia-Ming Wu
The purpose of this study was to realize the processing of dose distribution of RGK at the treatment isocenter at any gantry rotational angle by using an analytic geometry method to avoid inadequate arc therapy angles when implementing the treatment plan. Gaf chromic film was used for dose evaluation. A calibration curve was first obtained using linear accelerator irradiation. The 50% dose relative to the central axis at fixed gantry angles at the x-, y- and z-axes was obtained using Gaf chromic film and was compared to the analytic geometry method...
July 18, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28711480/commissioning-of-small-field-size-radiosurgery-cones-in-a-6-mv-flattening-filter-free-beam
#19
Juan Diego Azcona, Benigno Barbés, Verónica Morán, Javier Burguete
This study aimed to describe the commissioning of small field size radiosurgery cones in a 6-MV flattening filter free (FFF) beam and report our measured values. Four radiosurgery cones of diameters 5, 10, 12.5, and 15 mm supplied by Elekta Medical were commissioned in a 6-MV FFF beam from an Elekta Versa linear accelerator. The extraction of a reference signal for measuring small fields in scanning mode is challenging. A transmission chamber was attached to the lower part of the collimators and used for percentage depth dose (PDD) and profile measurements in scanning mode with a stereotactic diode...
July 12, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28711479/identification-of-the-suitable-leaf-margin-for-liver-stereotactic-body-radiotherapy-with-flattening-filter-free-beams
#20
Toshiyuki Ogata, Hideki Nishimura, Hiroshi Mayahara, Kazuyuki Uehara, Takanobu Okayama
The purpose of this study is to identify the suitable leaf margin for liver stereotactic body radiotherapy (SBRT) with flattening filter-free (FFF) beams, as compared with that with flattening filter (FF) beams. SBRT treatment planning for 10 patients with liver cancer was performed using 10-MV FFF and FF beams obtained from a Varian TrueBeam (Varian Medical Systems, Palo Alto, CA) linear accelerator. Each plan was generated with the leaf margin to the planning target volume (PTV) ranging from -3 to 5 mm...
July 12, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
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