Case report of visual biofeedback-driven, magnetic resonance-guided single-fraction SABR in breath hold for early stage non –small-cell lung cancer
We present the case of a 66-year-old male with history of cholangiocarcinoma who was subsequently diagnosed with peripheral earl y stage NSCLC and treated in mid-inspiration breath hold (BH) to 34 Gy in 1 fraction on a magnetic resonance (MR)-guided linear accelerator, with treatment delivery completed in 17 minutes. (Source: Medical Dosimetry)
Source: Medical Dosimetry - February 26, 2021 Category: Radiology Authors: Michael D. Chuong, Rupesh Kotecha, Minesh P. Mehta, Sonia Adamson, Tino Romaguera, Matthew D. Hall, Diane Alvarez, Alonso N. Gutierrez, Vivek Mishra, Fernando De Zarraga, Kathryn E. Mittauer Source Type: research
Intensity-modulated proton therapy (IMPT) versus intensity-modulated radiation therapy (IMRT) for the treatment of head and neck cancer: A dosimetric comparison
It is the goal of this study to compare the dosimetric advantages of IMPT when compared to IMRT. From January 2019 to August 2020, 25 patients were treated with intensity modulated proton therapy (IMPT) at our institution for either recurrent, metastatic, benign, or primary tumors in the head and neck region. Twenty-one patients met criteria for dosimetric analysis. Histology of disease included squamous cell carcinoma, acinic cell carcinoma, sarcomatoid sinonasal carcinoma, paraganglioma, adenoid cystic carcinoma, salivary high grade carcinoma, and papillary thyroid carcinoma. (Source: Medical Dosimetry)
Source: Medical Dosimetry - February 26, 2021 Category: Radiology Authors: My-Lien Nguyen, J. Nathan Cantrell, Salahuddin Ahmad, Christina Henson Source Type: research
Management of multiple brain metastases via dual-isocenter VMAT stereotactic radiosurgery
Single-isocenter volumetric modulated arc therapy (VMAT) stereotactic radiosurgery (SRS) techniques to treat multiple brain metastases simultaneously can significantly improve treatment delivery efficiency, patient compliance, and clinic workflow. However, due to large number of brain metastases sharing the same MLC pair causing island blocking, there is higher low- and intermediate-dose spillage to the normal brain and higher dose to organs-at-risk (OAR). To minimize this problem and improve plan quality, this study proposes a dual-isocenter planning strategy that groups lesions based on hemisphere location (left vs right...
Source: Medical Dosimetry - February 3, 2021 Category: Radiology Authors: Allison N Palmiero, Denise Fabian, William St Clair, Marcus Randall, Damodar Pokhrel Source Type: research
Dosimetric assessment of brass mesh bolus and transparent polymer-gel type bolus for commonly used breast treatment delivery techniques
We investigated skin dose enhancements of brass mesh bolus (BMB) and a recently developed transparent polymer-gel bolus (PGB) for clinically relevant breast treatment delivery techniques. The dose enhancement of the breast surface with BMB and PGB were compared to that of tissue-equivalent bolus.Three breast treatment plans were generated on CT scans of an anthropomorphic chest phantom: tangential step-and-shoot 3D conformal (3DCRT) planned using Field-in-Field (FiF), tangential sliding-window 3DCRT using Electronic Compensator (EC), and volumetric modulated arc therapy (VMAT). (Source: Medical Dosimetry)
Source: Medical Dosimetry - January 31, 2021 Category: Radiology Authors: Derek A. Fiedler, Sabrina Hoffman, John C. Roeske, Courtney L. Hentz, William Small, Hyejoo Kang Source Type: research
Dosimetric impact and modeling of prone breast positioning device and couch structures
In prone breast radiation, as the medial tangential beam usually passes through the immobilization board and couch, it is necessary to quantify the attenuation effect and the potential skin dose enhancement from these external structures. The prone breast board studied consists of an insert on which the contralateral breast rests and a board base indexed to the couch. Two different Varian couch systems were also studied. Transmission factors (TF) of the board were measured using a Farmer chamber at 4 cm depth. (Source: Medical Dosimetry)
Source: Medical Dosimetry - January 19, 2021 Category: Radiology Authors: Amy Lau, Kilian Salerno, Tianjun Ma, Iris Z. Wang Source Type: research
A case study of evaluating bilateral lung dose for VMAT treatment planning using a partial sagittal arc
Radiation pneumonitis (RP) is a potential toxic side effect of thoracic radiotherapy. Optimal planning techniques must maintain tumor coverage while limiting dose to normal lung tissue to reduce the risk of patients developing RP. The addition of a noncoplanar arc may be beneficial by increasing treatment angles and providing an ideal dose distribution for tumor coverage while decreasing dose to organs at risk (OAR). The purpose of this research was to compare the effects on the normal bilateral lung tissue receiving 20 Gy, 10 Gy and 5 Gy (V20, V10, V5) and the mean lung dose (MLD) values when medial lung tumors are treate...
Source: Medical Dosimetry - January 18, 2021 Category: Radiology Authors: Tenzin Yiga, Tiffany G. Lin, Brandon Williamson, Nishele Lenards, Ashley Hunzeker, Matt Tobler, Sabrina Zeiler, Ashley Fellows Source Type: research
Verification of the junctional dose for irradiation of the chest wall and supraclavicular regions under the circumstances of advanced technologies
This study verified the efficacy of an open leaf technique (OL-tech) that involves placing a multileaf collimator 5 mm outside from the beam central axis to remove the effect of the multileaf collimator in a single-isocenter half-beam technique. (Source: Medical Dosimetry)
Source: Medical Dosimetry - January 15, 2021 Category: Radiology Authors: Kengo Iwaki, Akira Kamaya, Nobukazu Fuwa, Kazuaki Tanisada, Kouji Matsueda, Takahiko Shibahara, Yukio Fujita, Etsuo Kunieda, Hideharu Todaka, Miwako Nomura, Noriko Ii Source Type: research
Proton beam therapy can achieve lower vertebral bone marrow dose than photon beam therapy during chemoradiation therapy of esophageal cancer
Chemoradiation therapy plays an important role in both the neoadjuvant and definitive management of esophageal cancer (EC). Prior studies have suggested that advanced planning techniques can better spare organs at risk including the heart. Although multiple toxicities can result from esophageal radiotherapy, one less studied acute toxicity is that of myelosuppression, which can result, in part, from the combination of chemotherapy and incidental radiotherapy administration to the vertebral bodies (VBs), which abut the posterior aspect of the esophagus, especially in the lower thoracic esophagus. (Source: Medical Dosimetry)
Source: Medical Dosimetry - January 13, 2021 Category: Radiology Authors: Yin Zhang, Salma K. Jabbour, Andrew Zhang, Bo Liu, Ning J. Yue, Nrusingh C. Biswal Source Type: research
Why all radiotherapy planning studies are wrong but some are useful
Dosimetry comparison studies of radiotherapy treatment planning are common, but often their limitations are not fully acknowledged. Useful data for the community may be produced, which is reproducible and reliable for implementation by others. However, this will only be achieved by clear and detailed reporting, and by consideration of delivered doses and clinical significance. (Source: Medical Dosimetry)
Source: Medical Dosimetry - January 7, 2021 Category: Radiology Authors: David J. Eaton Source Type: research
Description and evaluation of a new volumetric-modulated arc therapy plan complexity metric
This study describes a new plan complexity metric for volumetric-modulated arc therapy (VMAT) and evaluates the relationship of this metric with the VMAT dosimetric accuracy. The new modulation complexity score for VMAT (NMCSv) that is based on the aperture shape and multi-leaf collimator (MLC) leaf travel is described. Its performance is evaluated through correlation and receiver operating characteristic (ROC) analyses with patient-specific gamma passing rates using 2 3-dimensional diode arrays. (Source: Medical Dosimetry)
Source: Medical Dosimetry - December 19, 2020 Category: Radiology Authors: Guangjun Li, Wei Jiang, Yanlong Li, Qiang Wang, Jianghong Xiao, Renming Zhong, Sen Bai Source Type: research
The robustness of prostate radiotherapy for patients with hip prosthesis
The aim of this study was to investigate prostate radiotherapy techniques for the patients with hip prosthesis in 4 different field setups. Volumetric Modulated Arc Therapy (VMAT) technique was used in 4 different cases: (1) using full VMAT arcs (VMAT_F); (2) same arcs as in case 1 but with avoidance sectors (VMAT_ASEC); (3) as case 2 but with the addition of a lateral static field through the prosthesis (VMAT_ASEC+STAT); (4) as in case 1 but with an automated structure avoidance option to avoid irradiation through the prosthesis (VMAT_ASTR). (Source: Medical Dosimetry)
Source: Medical Dosimetry - December 18, 2020 Category: Radiology Authors: Miia Nadhum, Eeva Boman, Maija Rossi Source Type: research
Simple template-based optimization for pediatric total lymphoid irradiation (TLI) radiotherapy treatments
Total lymphoid irradiation (TLI) is used in the management of pediatric allogeneic hematopoietic stem cell transplantation (HSCT. This work aims to simplify the treatment planning process for TLI via a proposed template using the volumetric modulated arc therapy (VMAT) technique. Fifteen pediatric patients were planned, prescribed to 8 Gy in 4 fractions. Cost functions included in the template were the ones for the planning target volume (PTV), and conformality cost function (CCF) for the rest of the patient's volume. (Source: Medical Dosimetry)
Source: Medical Dosimetry - December 10, 2020 Category: Radiology Authors: C. Ferrer, C. Huertas, R. Plaza, P. de la Monja, A. Ocanto, A. Escribano, A. P érez, M. Sáez Source Type: research
Dynamic conformal arcs-based single-isocenter VMAT planning technique for radiosurgery of multiple brain metastases
Multiple small beamlets in the delivery of highly modulated single-isocenter HyperArc VMAT plan can lead to dose delivery errors associated with small-field dosimetry, which can be a major concern for stereotactic radiosurgery for multiple brain lesions. Herein, we describe and compare a clinically valuable dynamic conformal arc (DCA)-based VMAT (DCA-VMAT) approach for stereotactic radiosurgery of multiple brain lesions using flattening filter free beams to minimize this effect. Original single-isocenter HyperArc style VMAT and DCA-VMAT plans were created on 7 patients with 2 to 8 brain lesions (total 35 lesions) for 10 MV...
Source: Medical Dosimetry - December 8, 2020 Category: Radiology Authors: Damodar Pokhrel, Allison N. Palmiero, Mark E. Bernard, William St Clair Source Type: research
Performance evaluation of adaptive aperture's static and dynamic collimation in a compact pencil beam scanning proton therapy system: A dosimetric comparison study for multiple disease sites
This study evaluates dosimetric performance of SA and DA for different disease sites. This study includes 5 disease sites (brain, head and neck (HN), partial breast, lung, and prostate), and 8 patients for each. (Source: Medical Dosimetry)
Source: Medical Dosimetry - December 2, 2020 Category: Radiology Authors: Hardev S. Grewal, Salahuddin Ahmad, Hosang Jin Source Type: research
Comparative evaluation of treatment plan quality for a prototype biology-guided radiotherapy system in the treatment of nasopharyngeal carcinoma
We aimed to compare prototype treatment plans for a new biology-guided radiotherapy (BgRT) machine in its intensity-modulated radiation therapy (IMRT) mode with those using existing IMRT delivery techniques in treatment of nasopharyngeal carcinoma (NPC). We retrospectively selected ten previous NPC patients treated in 33 fractions according to the NRG-HN001 treatment protocol. Three treatment plans were generated for each patient: a helical tomotherapy (HT) plan with a 2.5-cm jaw, a volumetric modulated arc therapy (VMAT) plan using 2 to 4 6-MV arc fields, and a prototype IMRT plan for a new BgRT system which uses a 6-MV p...
Source: Medical Dosimetry - November 30, 2020 Category: Radiology Authors: Chunhui Han, Angela J. Da Silva, Jieming Liang, Christopher Wohlers, Cal Huntzinger, John P. Neylon, Dongsu Du, Jeffrey Y.C. Wong, An Liu Source Type: research
