Treatment Delivery Process Research Articles

Impact of Hadang and Bentengan Game on Students’ Physical Fitness Levels

This research aims to determine the effectiveness of blocking and fortification games on the physical fitness level of elementary school students. The research method used was experimental using a two-group pretest-posttest design. The sampling technique used purposive sampling and the sample consisted of 54 students. Data collection techniques are 1) documents taken from the results of learning notes during the treatment delivery process, and 2) physical fitness tests is to know physical fitness level. The data analysis technique uses the t-test, but the data analysed must have a normal distribution so that the level of normality and homogeneity of the data is first tested. The t-test results for the Hadang and Bentengan games showed statistically significant increases in physical fitness (e.g., t = 29.105 for Hadang, t = 21.236 for Bentengan, both p 0.05)., so it can be concluded that there was an increase in physical fitness through the Bentengan game. Students' physical fitness levels experienced a significant increase in sprints, pull-ups, sit-ups, vertical jumps and short-distance running activities. The results of this research also have implications for the development of various types of traditional games for other physical fitness learning activities or other health, sports and physical fitness learning activities. Teachers can design types of games as teaching techniques and can be adjusted to the age needs of students such as for elementary or junior high school levels.

Cherenkov and Plan Integration for Real-Time Delivery Verification: The Opportunity for Automated Visualization and Guidance of All Treatments in EBRT

Initiatives in the national radiation oncology incident learning system (RO-ILS) have been exceptionally useful in discovery of factors that lead to incidents and learning of best practices that can help make the national practice of RO safer as a whole. Incident learning systems come from the flight industry, where both visual cues and instrument control are essential parts of implementation, and similarly both human and instrument tools are used in RO. However, numerous RO studies have reported that human factors are a leading cause of incidents discovered and that timelines, such as QA, setup, delivery, and verification are areas where most incidents are found. Tools such as Cherenkov imaging and SGRT can be used to automate many of the riskiest human decisions and/or providing both human vision and instrument-guided oversight in these areas of treatment delivery process. The value of continuous online imaging is reviewed and the two parts have been tested towards complete automation. The conceptual framework of comparing images to the patient treatment plan is outlined with software examples. Development towards a combined SGRT & Cherenkov imaging system that could achieve fully automated incident detection is outlined. Cherenkov imaging has shown direct visualization of many instances of beam delivery to patients that were sub-optimal. These are seen mostly in isolated cases of normal tissue in the beam where it was not expected, such as limbs, chin, contralateral breast or axilla. Incorrect placement of bolus is also readily visualized. Comparisons can be made on a day-to-day basis, but also on a delivery to plan basis if the plan was incorporated into the treatment delivery process. Analysis of the incidents seen indicates that there are automatable metrics of image quality that could have detected them. Overall, if the system detection of variations were fully automated, these could be detected without human intervention. The capabilities for reducing nearly all human error in setup and delivery are available or emerging, and Cherenkov imaging is perhaps one of the most direct ways to capture and computationally analyze the treatment in real time. These tools require further integration with automated analysis and plan integration, but the initial steps are well underway and individual parts are now possible with advances in R&D of the system integration.

Advancing Precision in Post-mastectomy Chest Wall Radiotherapy: A Comparative Dosimetric Analysis of Volumetric-Modulated Arc Therapy (VMAT) and Intensity-Modulated Radiotherapy (IMRT) Based on Institutional Experience.

Post-mastectomy radiation therapy (PMRT) is an important component in the management of breast cancer patients who have undergone mastectomy. Intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) are two popular methods of delivering PMRT. With IMRT, high radiation doses are directed at the tumor, while exposure to healthy tissue is kept to a minimum. VMAT, on the other hand, is a more advanced version of IMRT that allows for faster radiation dose delivery while maintaining precision. The complexity of the VMAT treatment planning and delivery process, on the other hand, may increase the risk of technical errors, which can reduce treatment effectiveness. Studies have compared VMAT and IMRT in PMRT for breast cancer patients, but most have found no significant differences in treatment outcomes between the two methods. Individual patient factors such as treatment goals, available resources, and other characteristics may influence the choice between the two techniques. This prospective observational study aimed to compare the dosimetry of two cutting-edge modern radiotherapy techniques for post-mastectomy breast cancer patients receiving hypofractionated doses. For 58 patients with breast cancer, 116 plans for radiotherapy treatment were generated by both VMAT and IMRT. To maintain the uniformity of contouring, every CT image was contoured by the same physician, and Radiotherapy Oncology Group (RTOG) contouring guidelines were strictly followed during contouring. Both techniques had comparable target volume coverage, but VMAT produced a significantly better conformity index than IMRT for both the left (0.71 vs. 0.65) and right (0.72 vs. 0.66) breasts (p-value < 0.05). VMAT plans had significantly higher low-dose spillage to the ipsilateral lung (V5Gy and V10Gy) but significantly lower high-dose spillage (V20Gy, V30Gy, and V40Gy) than IMRT plans (p-value < 0.05). Dmax and Dmean for the ipsilateral lung were comparable for both techniques. When compared to alternative treatment approaches, IMRT treatment plans were found to be more effective in minimizing radiation exposure to the heart for all patients with right-sided breast cancer, resulting in considerably lower levels of Dmean, V5Gy, V10Gy, V20Gy, and V35Gy. Plans for VMAT treatment were found to be significantly superior to left-side chest wall radiotherapy in terms of lower exposure to the heart for higher doses. IMRT plans, on the other hand, were successful in dramatically lowering the levels of Dmax that reached the spinal cord for both right- and left-sided breast cancers. Apart from similar planning target volume (PTV) coverage to IMRT plans, VMAT produced significantly better conformity. VMAT plans have more low-dose spillage to normal tissues, while IMRT plans spare various organs at risk significantly better at lower doses in both right and left-sided breast cancer. VMAT was found to be better at sparing the heart (in left-sided breast cancer only) and ipsilateral lung at a high dose range. The best radiotherapy approach for breast cancer should be established on an individual basis, taking into account tumor laterality and the risk-benefit ratio.

PO-05-104 FEASIBILITY STUDY OF SINGLE DAY SIMULATION- FREE CARDIAC RADIOABLATION WORKFLOW WITH A PORCINE MODEL

Cardiac radioablation (CRA) is a novel and expanding treatment option for patients with ventricular tachycardia (VT). CRA is a complex process involving interdisciplinary collaboration and requires multiple days between patient imaging and treatment delivery. For patients with active VT, this wait is difficult. Improving efficiency and standardization of CRA workflows is critically important for controllably implementing and assessing this novel treatment approach for research and clinical deployment. We hypothesized that by leveraging state-of-the-art technology within radiotherapy, key steps in the treatment planning and delivery process may be condensed to a single session on the treatment machine. Investigate the feasibility of CRA treatment in a single day, simulation-free workflow with a porcine model. Under an approved animal studies protocol, CRA was performed using a porcine model. In this workflow the animal was brought to radiation oncology under anesthesia under the supervision of a veterinary care team and was placed in the decubitus position on a dedicated research ring gantry linear accelerator platform. The ventilation rate of the animal was set to 8 breaths per minutes. A 6 second cone beam computed tomography scan was completed during exhalation while IV contrast was simultaneously administered. Images were reviewed by a radiation oncologist, medical physicist, and electrophysiologist. Organs at risk as well as the site of the VT target site were contoured. A radiation treatment plan was developed on this data set and reviewed by the treatment team. A CBCT was repeated to confirm alignment of the animal. The animal then received CRA to 25 Gy to planning target volume (PTV) in a single fraction. Simulation-free cardiac radioablation was successfully delivered to a pig in a single session using a commercially available ring gantry linear accelerator. This study demonstrates feasibility of conducting a simulation-free preclinical animal study of CRA using a commercially available linear accelerator and ultimately moves the field closer to same-day cardiac radioablation.

PD-0491 Failure Mode and Effects Analysis (FMEA) evaluation of the radiotherapy treatment delivery process.

PD-0491 Failure Mode and Effects Analysis (FMEA) evaluation of the radiotherapy treatment delivery process.

Evolving practice in global healthcare: Remote physics support for low- and middle-income countries.

The COVID-19 pandemic has disrupted traditional onsite support for radiotherapy clinics in low- and middle-income countries (LMIC). Clinics there have struggled to commission new techniques and receive onsite training for their staff. We sought to evaluate whether an offsite approach could fill this gap at a clinic in Jordan by requesting a clinical audit and attempting to commission volumetric modulated arc therapy (VMAT). Over 13 months, a consultant provided remote support for a radiotherapy center that had already obtained treatment equipment and licenses. The consultant began by conducting a virtual audit, using a remote login to the center's R&V and TPS, to identify any gaps in the clinical workflow. Suggestions for improving the clinical workflow were proposed, and change implementation was tracked through emails, social media apps, and video conferencing. An extensive table outlined the commissioning process, including all measurements to be done. Social media apps and shared documents were used to track measurements and analysis. The lack of person-to-person interaction in this new remote-support ecosystem created conflicts; we have highlighted some of these, as well as their resolution and the lessons learned from them. The virtual audit identified gaps categorized as machine QA, treatment plan review, and treatment delivery processes. Following the implementation of the proposals, motion management was added, and machine QA became more comprehensive. VMAT was commissioned using the reports of the AAPM and the IAEA. The main challenges for remote support were time difference, establishing an appropriate form and frequency of communication, tone of voice used in messages, and buy-in from local staff. This evolving practice will enable medical physicists to use modern, multimodal remote communication pathways to effectively transfer knowledge to centers in LMICs. The audit-proposal-improvement pathway for remote support can be incorporated to help others while avoiding the pitfalls we faced.

Development of a quality assurance system in radiation oncology: A 12-year experience in a University Hospital.

This study aimed to report 12 years of experience in the development of a quality assurance system in radiation oncology in a university hospital. We developed the Quality Assurance Program in Radiation Oncology (QUAPRO) in 2008 to detect treatment deviation in the radiotherapy (RT) process with three steps of near-miss detection: simulation and prescription (primary check, PC), treatment planning (secondary check, SC), and treatment delivery process (tertiary check, TC). We transferred our paper-based medical records to electronic-based radiotherapy information systems (RTISs) in 2013. QUAPRO was completely integrated into RTIS in 2017. Since then, electronic-based incident reporting has been conducted. The program is called the Radiation Incident Learning System (RILS). The near-miss rates were compared during the three time periods: 2008-2012, 2013-2017, and 2017-2020. Five years of paper-based QUAPRO for 2008-2012 demonstrated a fluctuation in the checking ratio, with a gradually increasing rate of near misses of 3.5-19.7%. After electronic-based medical records were developed in 2013, the results revealed a dramatic increase from a rate of 2.7 to 4.2 in the number of checks per patient and achieved an increased rate of near misses of 24.7% for PC, SC, and TC. The rate of near misses gradually decreased to 5.3% after 2017 because of RT workflow improvement. The analysis of 12 years in near-miss data reflected the effectiveness of our quality assurance program. The QUAPRO system can detect near-miss incidents in the whole RT workflow and illustrate the detection improvement when integrated into electronic-based medical records. Regular feedback and exploration of near-miss reporting are recommended for proper RT workflow improvement.

The Promise of Magnetic Resonance Imaging in Radiation Oncology Practice in the Management of Brain, Prostate, and GI Malignancies.

Magnetic resonance imaging (MRI) has a key role to play at multiple steps of the radiotherapy (RT) treatment planning and delivery process. Development of high-precision RT techniques such as intensity-modulated RT, stereotactic ablative RT, and particle beam therapy has enabled oncologists to escalate RT dose to the target while restricting doses to organs at risk (OAR). MRI plays a critical role in target volume delineation in various disease sites, thus ensuring that these high-precision techniques can be safely implemented. Accurate identification of gross disease has also enabled selective dose escalation as a means to widen the therapeutic index. Morphological and functional MRI sequences have also facilitated an understanding of temporal changes in target volumes and OAR during a course of RT, allowing for midtreatment volumetric and biological adaptation. The latest advancement in linear accelerator technology has led to the incorporation of an MRI scanner in the treatment unit. MRI-guided RT provides the opportunity for MRI-only workflow along with online adaptation for either target or OAR or both. MRI plays a key role in post-treatment response evaluation and is an important tool for guiding decision making. In this review, we briefly discuss the RT-related applications of MRI in the management of brain, prostate, and GI malignancies.

Proton Therapy for Prostate Cancer: Challenges and Opportunities.

Simple SummaryReported clinical outcomes of proton therapy (PT) for localized prostate cancer are similar to photon-based external beam radiotherapy. Apparently, the dosimetric advantages of PT have yet to be translated to clinical benefits. The suboptimal clinical outcomes of PT might be attributable to inadequate dose prescription, as indicated by the ASCENDE-RT trial. Moreover, uncertainties involved in the treatment planning and delivery processes, as well as technological limitations in PT treatment systems, may lead to discrepancies between planned doses and actual doses delivered to patients. In this article, we reviewed the current status of PT for prostate cancer and discussed different clinical implementations that could potentially improve the clinical outcome of PT for prostate cancer. Various technological advancements under which uncertainties in dose calculations can be minimized, including MRI-guided PT, dual-energy photon-counting CT and high-resolution Monte Carlo-based treatment planning systems, are highlighted.The dosimetric advantages of proton therapy (PT) treatment plans are demonstrably superior to photon-based external beam radiotherapy (EBRT) for localized prostate cancer, but the reported clinical outcomes are similar. This may be due to inadequate dose prescription, especially in high-risk disease, as indicated by the ASCENDE-RT trial. Alternatively, the lack of clinical benefits with PT may be attributable to improper dose delivery, mainly due to geometric and dosimetric uncertainties during treatment planning, as well as delivery procedures that compromise the dose conformity of treatments. Advanced high-precision PT technologies, and treatment planning and beam delivery techniques are being developed to address these uncertainties. For instance, external magnetic resonance imaging (MRI)-guided patient setup rooms are being developed to improve the accuracy of patient positioning for treatment. In-room MRI-guided patient positioning systems are also being investigated to improve the geometric accuracy of PT. Soon, high-dose rate beam delivery systems will shorten beam delivery time to within one breath hold, minimizing the effects of organ motion and patient movements. Dual-energy photon-counting computed tomography and high-resolution Monte Carlo-based treatment planning systems are available to minimize uncertainties in dose planning calculations. Advanced in-room treatment verification tools such as prompt gamma detector systems will be used to verify the depth of PT. Clinical implementation of these new technologies is expected to improve the accuracy and dose conformity of PT in the treatment of localized prostate cancers, and lead to better clinical outcomes. Improvement in dose conformity may also facilitate dose escalation, improving local control and implementation of hypofractionation treatment schemes to improve patient throughput and make PT more cost effective.

Dosimetric Effects of a Commercial Breast Board Patient Support System

Aim: In prone breast treatments, a carbon fiber support device resides under the contralateral breast. Tangent beams are designed to encompass the treated breast and these often pass through the board at a shallow angle, resulting in significant attenuation. Our planners account for this attenuation by adding field-in-field dose to the deep part of the breast, through the board. Concern was raised about how accurate the treatment delivery is when the inherent uncertainties of patients’ positions are accounted for. Furthermore, transmission measurements are usually carried out perpendicular to the board, a non-clinical situation. The goal of this study is to evaluate the dosimetric effect of the board and the robustness of the plan to positional uncertainty. Materials and Methods: Twenty-two breast patients treated on a commercial prone breast board between 2017 and 2020 were selected for this retrospective study. To evaluate the board’s attenuation, we compared the plans with the board removed from the dose calculation. To quantify the robustness of this technique, we moved the beam isocenter with respect to the patient and board. Results: Our results showed that when the breast board is removed from a plan which was designed to account for the board attenuation, the average point dose increases by 7.48%, with a maximum of 22%. Comparing results with a mixed Analysis of Variance (ANOVA) and a least-square means analysis, our robustness evaluation indicates that anterior shifts at every magnitude (1 mm through 5 mm) make a significant difference in all dose statistics (D95, max, 95% prescription coverage and homogeneity index) investigated. In/out and right/left shifts resulted in an insignificant change in dose statistics. Conclusion: Prone breast boards can add significant dosimetric uncertainty into the treatment delivery process. Accounting for plan robustness in the design of the plan is highly recommended. A prone breast board design with support moved away from the beam path is warranted.

Fully automated planning and delivery of hippocampal-sparing whole brain irradiation.

The goal of this study is to fully automate the treatment planning and delivery process of hippocampal-sparing whole brain irradiation (HS-WBRT) by combining a RapidPlan (RP) knowledge-based planning model and HyperArc (HA) technology. Additionally, this study compares the dosimetric performance of RapidPlan-HyperArc (RP-HA) treatment plans with RP plans and volumetric modulated arc therapy (VMAT) plans. Ten patients previously treated with HS-WBRT using conventional VMAT were re-planned using RP-HA technique and RP model for HS-WBRT. Treatment plans were generated for 30Gy in 3Gy fractions using 6MV photon beam on a TrueBeam linear accelerator (Varian Medical Systems, Palo Alto, CA) equipped with high definition multileaf collimator (HDMLC). Target coverage, homogeneity index (HI), Paddick Conformity index (CI), dose to organs-at-risk (OARs) provided by the 3 planning modalities were compared, and a paired t-test was performed. Total number of monitor units (MU), effective planning time and beam-on-time time were reported and evaluated for each plan. RP-HA plans achieved on average a 4% increase in D98% of PTV, a 26% improvement in HI, a 2.3% increase in CI, when compared to RP plans. Furthermore, RP-HA plans provided on average 11% decrease in D100% of hippocampi when compared to VMAT plans. All RP-HA plans were generated in less than 30 minutes while RP plans took 40 minutes and VMAT plans required on average 9 hours to complete. Regarding beam-on-time time, it was estimated that RP-HA plans take on average 5 minutes to deliver while RP and VMAT plans require 6.5 and 10 minutes, respectively. RP-HA method provides fully automated planning and delivery for HS-WBRT. The auto-generated plans together with automated treatment delivery allow standardization of plan quality, increased efficiency and ultimately improved patient care.

Magnetic resonance linear accelerator technology and adaptive radiation therapy: An overview for clinicians.

Radiation therapy (RT) continues to play an important role in the treatment of cancer. Adaptive RT (ART) is a novel method through which RT treatments are evolving. With the ART approach, computed tomography or magnetic resonance (MR) images are obtained as part of the treatment delivery process. This enables the adaptation of the irradiated volume to account for changes in organ and/or tumor position, movement, size, or shape that may occur over the course of treatment. The advantages and challenges of ART maybe somewhat abstract to oncologists and clinicians outside of the specialty of radiation oncology. ART is positioned to affect many different types of cancer. There is a wide spectrum of hypothesized benefits, from small toxicity improvements to meaningful gains in overall survival. The use and application of this novel technology should be understood by the oncologic community at large, such that it can be appropriately contextualized within the landscape of cancer therapies. Likewise, the need to test these advances is pressing. MR-guided ART (MRgART) is an emerging, extended modality of ART that expands upon and further advances the capabilities of ART. MRgART presents unique opportunities to iteratively improve adaptive image guidance. However, although the MRgART adaptive process advances ART to previously unattained levels, it can be more expensive, time-consuming, and complex. In this review, the authors present an overview for clinicians describing the process of ART and specifically MRgART.

Departmental quality initiative to establish turnaround times from simulation to treatment.

IntroductionThe process of treatment delivery involves a series of steps from patient evaluation, therapeutic simulation (simulation), followed by dosimetric treatment planning, pre-treatment quality assurance and plan verification, and ultimately treatment delivery. Each step has a strict precedence relationship, requiring the preceding task to be completed prior to the initiation of the next task. The minimum time for a patient to undergo treatment is based on the summation of times of the individual tasks. Nevertheless, patients are often scheduled based on factors that do not directly consider the overall time required to complete these steps.Materials and methodsTo better help in scheduling patients and to ensure quality and safety of treatment planning and delivery, we undertook a quality initiative based on team members tabulating time required to complete tasks required for treatment delivery. We established “fastest possible” turnaround times based how quickly a task could be accomplished if there were minimal or no competing obligations, as well as processing times under routine operating conditions.ResultsFor urgent situations, we found that our center can accommodate treatment within 24 h. For routine plans using 3D conformal radiation, an approximately 1-week turnaround time is needed. For patients being treated with IMRT/VMAT an approximately 2-week turnaround time is needed.ConclusionsThe growing complexity of radiotherapy delivery also requires additional steps which has increased turnaround times from simulation to treatment compared to historical standards. We report our estimates for turnaround time based on plan type and acuity level. While our turnaround times may not be applicable to all centers, we believe that this exercise was helpful to facilitate inter- and intra- departmental communication regarding reasonable start times for patients.

A Modular System for Treating Moving Anatomical Targets With Scanned Ion Beams at Multiple Facilities: Pre-Clinical Testing for Quality and Safety of Beam Delivery.

BackgroundQuality management and safety are integral to modern radiotherapy. New radiotherapy technologies require new consensus guidelines on quality and safety. Established analysis strategies, such as the failure modes and effects analysis (FMEA) and incident learning systems have been developed as tools to assess the safety of several types of radiation therapies. An extensive literature documents the widespread application of risk analysis methods to photon radiation therapy. Relatively little attention has been paid to performing risk analyses of nascent radiation therapy systems to treat moving tumors with scanned heavy ion beams. The purpose of this study was to apply a comprehensive safety analysis strategy to a motion-synchronized dose delivery system (M-DDS) for ion therapy.MethodsWe applied a risk analysis method to new treatment planning and treatment delivery processes with scanned heavy ion beams. The processes utilize a prototype, modular dose delivery system, currently undergoing preclinical testing, that provides new capabilities for treating moving anatomy. Each step in the treatment process was listed in a process map, potential errors for each step were identified and scored using the risk probability number in an FMEA, and the possible causes of each error were described in a fault tree analysis. Solutions were identified to mitigate the risk of these errors, including permanent corrective actions, periodic quality assurance (QA) tests, and patient specific QA (PSQA) tests. Each solution was tested experimentally.ResultsThe analysis revealed 58 potential errors that could compromise beam delivery quality or safety. Each of the 14 binary (pass-or-fail) tests passed. Each of the nine QA and four PSQA tests were within anticipated clinical specifications. The modular M-DDS was modified accordingly, and was found to function at two centers.ConclusionWe have applied a comprehensive risk analysis strategy to the M-DDS and shown that it is a clinically viable motion mitigation strategy. The described strategy can be utilized at any ion therapy center that operates with the modular M-DDS. The approach can also be adapted for use at other facilities and can be combined with existing safety analysis systems.

Use of a Checklist Approach on a Telecobalt in an Attempt to Reduce Human Errors in Radiotherapy Delivery and Improve Therapeutic Ratio.

Background:The process of radiotherapy treatment planning and delivery involves multiple steps and professionals causing it to be prone to errors. Radiotherapy centers equipped with old telecobalt machines have certain peculiar challenges to workflow. We designed and tested a checklist for radiotherapy technicians (RTTs) to reduce chances of error during treatment delivery on a telecobalt machine.Materials and Methods:A physical checklist was designed for RTTs to use in the pretreatment pause using a template advocated by the American Association of Physicists in Medicine. It was tested on 4 RTTs over 1000 radiotherapy delivery sittings.Results:The checklist helped to rectify 41 documentary lapses and 28 errors in radiotherapy treatment parameters while also identifying 12 instances where treatment plan modifications were due and 30 where the patient was due for review by the radiation oncologist. The average time to go through the checklist was between 2.5 and 3 min.Conclusions:The development and use of the checklist has helped in reducing errors and also improving workflow in our department. It is recommended to utilize such physical checklists in all radiotherapy centers with telecobalt machines. The success of the checklist depends upon leadership, teamwork, acceptance of a need to inculcate a “safety culture,” with voluntary error-reporting and a willingness to learn from such errors.

Technical Note: Deep Learning approach for automatic detection and identification of patient positioning devices for radiation therapy.

Automatic detection and identification of setup devices, using a deep convolutional neural network (CNN) for real-time multiclass object detection, has the potential to reduce errors in the treatment delivery process by avoiding documentation errors. A database of the setup device photos from the most recent 1200 patients treated at our institution was downloaded from the record and verify (R&V) system along with the corresponding setup notes. Images were manually labeled with bounding boxes of each device. A real-time object detection CNN using the "you only look once" (YOLOv2) architecture was trained using transfer learning of a pretrained CNN (ResNet50). The CNN was trained to detect and identify 11 of the most common treatment accessories used at our institution. Using transfer learning of a CNN for multiclass object detection, we are able to automatically detect and identify setup devices in photographs with an accuracy of 96%. Automation in radiation oncology has the potential to reduce risk. Automatic detection of setup devices is possible using a CNN and transfer learning. This work shows both the value of incident learning systems (ILS) in practice knowledge dissemination, and shows how automation of clinical processes and less reliance on manual documentation has the potential for risk reduction in radiation oncology treatments.

A review of patient questions from physicist-patient consults.

PurposeTo provide insight into the types of questions asked to medical physicists by patients during one‐on‐one physicist–patient consults at one institution.Materials and MethodsMedical physicists trained in patient communication techniques met with patients to provide an overview of the treatment planning and delivery processes, discuss the patient's treatment plan, and answer any technical questions. From August 2016 to December 2019, 152 physicist–patient consults were conducted. In the initial months of the study (August 2016—December 2017), following each physicist–patient consult, all patient questions were documented by the physicists. For the remaining time period (January 2018—December 2019), any newly encountered questions were periodically added to the list. The questions were compiled into a comprehensive list and organized into categories.ResultsThere were a total of 88 unique patient questions. These questions fit into four topical categories. Fifty‐four questions (61.4%) were in the “Treatment Planning and Delivery Questions” category, 15 questions (17.1%) were in the “General Radiation Questions or Concerns” category, 13 questions (14.8%) were in the “Safety and Quality Assurance Questions” category, and 6 questions (6.8%) were in the “Medical Questions” category. Overall, patients were primarily concerned about how radiation works, the treatment planning and delivery processes, and what is being done to keep them safe throughout their treatment.ConclusionPhysicist–patient consults provided an opportunity to address the technical aspects of radiation therapy with patients in greater detail. The fact that patient questions could be conveniently grouped into only four topical categories indicates that it may be straightforward for other medical physicists to prepare for effectively addressing technical questions during physicist–patient consults.

ACR-ASTRO Practice Parameter for Image-guided Radiation Therapy (IGRT).

The American College of Radiology (ACR) and the American Society for Radiation Oncology (ASTRO) have jointly developed the following practice parameter for image-guided radiation therapy (IGRT). IGRT is radiation therapy that employs imaging to maximize accuracy and precision throughout the entire process of treatment delivery with the goal of optimizing accuracy and reliability of radiation therapy to the target, while minimizing dose to normal tissues. The ACR-ASTRO Practice Parameter for IGRT was revised according to the process described on the ACR website ("The Process for Developing ACR Practice Parameters and Technical Standards," www.acr.org/ClinicalResources/Practice-Parametersand-Technical-Standards) by the Committee on Practice Parameters of the ACR Commission on Radiation Oncology in collaboration with the ASTRO. Both societies then reviewed and approved the document. This practice parameter is developed to serve as a tool in the appropriate application of IGRT in the care of patients with conditions where radiation therapy is indicated. It addresses clinical implementation of IGRT including personnel qualifications, quality assurance standards, indications, and suggested documentation. This practice parameter is a tool to guide clinical use of IGRT and does not make recommendations on site-specific IGRT directives. It focuses on the best practices and principles to consider when using IGRT effectively, especially with the significant increase in imaging data that is now available with IGRT. The clinical benefit and medical necessity of the imaging modality and frequency of IGRT should be assessed for each patient.

Hollow silica nanoparticles synthesized from core-shell nanoparticles as highly efficient adsorbent for methylene blue and its invitro release: Mechanism and Kinetics study

In this study, hollow silica nanoparticles (HSNPs) were prepared by acidic etching of core of core-shell nanoparticles (ZnSe@SiO2 shell). HSNPs were confirmed from X-ray diffraction (XRD), transmission electron microscope (TEM) and Raman spectroscopy, demonstrating amorphous silica peak, hollow structure, and prominent D1 and D2 Raman peaks of silica. Langmuir and Freundlich model analysis showed adsorption of methylene blue (MB) by HSNPs to be of chemisorption type, with adsorption capacity of 64.06 mg/g. Reaction kinetics was found to be of pseudo-second-order, interparticle diffusion model and Byod’s model predicts that adsorption mechanism follows both film and pore diffusion process, and external mass transport phenomenon. Moreover, adsorption study on bare and silica shell coated NPs of ZnSe and CdSe signifies that voids and hollow nature of HSNPs favors more adsorption of MB than its counterparts. Reusability experiments showed > 80% dye adsorption efficiency, after fifth cycle of reuse. Also, MB invitro release study form HSNPs was conducted, and different models like Higuchi, first order kinetic decay, Korsmeyer-Peppas model were applied suggesting a diffusion controlled mechanism of release. This study aims to provide knowledge about dye adsorption and its sustained release mechanism, finding applications in water treatment and invitro delivery process.

Measurement validation of treatment planning for a MR-Linac.

PurposeThe magnetic field can cause a nonnegligible dosimetric effect in an MR‐Linac system. This effect should be accurately accounted for by the beam models in treatment planning systems (TPS). The purpose of the study was to verify the beam model and the entire treatment planning and delivery process for a 1.5 T MR‐Linac based on comprehensive dosimetric measurements and end‐to‐end tests.Material and methodsDosimetry measurements and end‐to‐end tests were performed on a preclinical MR‐Linac (Elekta AB) using a multitude of detectors and were compared to the corresponding beam model calculations from the TPS for the MR‐Linac. Measurement devices included ion chambers (IC), diamond detector, radiochromic film, and MR‐compatible ion chamber array and diode array. The dose in inhomogeneous phantom was also verified. The end‐to‐end tests include the generation, delivery, and comparison of 3D and IMRT plan with measurement.ResultsFor the depth dose measurements with Farmer IC, micro IC and diamond detector, the absolute difference between most measurement points and beam model calculation beyond the buildup region were <1%, at most 2% for a few measurement points. For the beam profile measurements, the absolute differences were no more than 1% outside the penumbra region and no more than 2.5% inside the penumbra region. Results of end‐to‐end tests demonstrated that three 3D static plans with single 5 × 10 cm2 fields (at gantry angle 0°, 90° and 270°) and two IMRT plans successfully passed gamma analysis with clinical criteria. The dose difference in the inhomogeneous phantom between the calculation and measurement was within 1.0%.ConclusionsBoth relative and absolute dosimetry measurements agreed well with the TPS calculation, indicating that the beam model for MR‐Linac properly accounts for the magnetic field effect. The end‐to‐end tests verified the entire treatment planning process.