Per H. Halvorsen

The next decade for clinical medical physics.

This issues editorial is an invited commentary authored by Per H. Halvorsen.* It discusses an essential question for clinically practicing medical physicists: How are external factors likely to change the way we practice our profession in the next decade? The topic is both timely and essential, as the AAPM is actively engaged in developing guidance on many related aspects. This editorial sets the framework and provides the personal observations of an individual who has led the AAPMs Professional Council for the past six years.

AAPM‐RSS Medical Physics Practice Guideline 9.a. for SRS‐SBRT

The American Association of Physicists in Medicine (AAPM) is a nonprofit professional society whose primary purposes are to advance the science, education, and professional practice of medical physics. The AAPM has more than 8,000 members and is the principal organization of medical physicists in the United States. The AAPM will periodically define new practice guidelines for medical physics practice to help advance the science of medical physics and to improve the quality of service to patients throughout the United States. Existing medical physics practice guidelines will be reviewed for revision or renewal, as appropriate, on their fifth anniversary or sooner. Each medical physics practice guideline represents a policy statement by the AAPM, has undergone a thorough consensus process in which it has been subjected to extensive review, and requires the approval of the Professional Council. The medical physics practice guidelines recognize that the safe and effective use of diagnostic and therapeutic radiology requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice guidelines and technical standards by those entities not providing these services is not authorized. The following terms are used in the AAPM practice guidelines: Must and Must Not: Used to indicate that adherence to the recommendation is considered necessary to conform to this practice guideline. Should and Should Not: Used to indicate a prudent practice to which exceptions may occasionally be made in appropriate circumstances. Approved by AAPM Professional Council 3‐31‐2017 and Executive Committee 4‐4‐2017.

AAPM Medical Physics Practice Guideline 3.a: Levels of supervision for medical physicists in clinical training.

The American Association of Physicists in Medicine (AAPM) is a nonprofit professional society whose primary purposes are to advance the science, education and professional practice of medical physics. The AAPM has more than 8,000 members and is the principal organization of medical physicists in the United States. The AAPM will periodically define new practice guidelines for medical physics practice to help advance the science of medical physics and to improve the quality of service to patients throughout the United States. Existing medical physics practice guidelines will be reviewed for the purpose of revision or renewal, as appropriate, on their fifth anniversary or sooner. Each medical physics practice guideline represents a policy statement by the AAPM, has undergone a thorough consensus process in which it has been subjected to extensive review, and requires the approval of the Professional Council. The medical physics practice guidelines recognize that the safe and effective use of diagnostic and therapeutic radiology requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice guidelines and technical standards by those entities not providing these services is not authorized. The following terms are used in the AAPM practice guidelines: Must and Must Not: Used to indicate that adherence to the recommendation is considered necessary to conform to this practice guideline. Should and Should Not: Used to indicate a prudent practice to which exceptions may occasionally be made in appropriate circumstances.

Medical Physics Practice Guidelines ‐ The AAPM's minimum practice recommendations for medical physicists

This issues editorial is an invited commentary authored by Maria F. Chan, Joann I. Prisciandaro, S. Jeff Shepard, and Per H. Halvorsen. It discusses an essential question for practicing medical physicists: What are minimum practice standards and recommendations for clinically active medical physicists? The topic is both timely and essential, as the AAPM and JACMP are beginning to publish community practice standards. This editorial sets the framework and focus of these important articles. Michael D. Mills PhD Editor‐in‐Chief

Commissioning and quality assurance for the treatment delivery components of the AccuBoost system

The objective for this work was to develop a commissioning methodology for the treatment delivery components of the AccuBoost system, as well as to establish a routine quality assurance program and appropriate guidance for clinical use based on the commissioning results. Various tests were developed: 1) assessment of the accuracy of the displayed separation value; 2) validation of the dwell positions within each applicator; 3) assessment of the accuracy and precision of the applicator localization system; 4) assessment of the combined dose profile of two opposed applicators to confirm that they are coaxial; 5) measurement of the absolute dose delivered with each applicator to confirm acceptable agreement with dose based on Monte Carlo modeling; 6) measurements of the skin‐to‐center dose ratio using optically stimulated luminescence dosimeters; and 7) assessment of the mammopad cushions effect on the center dose. We found that the difference between the measured and the actual paddle separation is <0.1 cm for the separation range of 3 cm to 7.5 cm. Radiochromic film measurements demonstrated that the number of dwell positions inside the applicators agree with the values from the vendor, for each applicator type and size. The shift needed for a good applicator‐grid alignment was within 0.2 cm. The dry‐run test using film demonstrated that the shift of the dosimetric center is within 0.15 cm. Dose measurements in water converted to polystyrene agreed within 5.0% with the Monte Carlo data in polystyrene for the same applicator type, size, and depth. A solid water‐to‐water (phantom) factor was obtained for each applicator, and all future annual quality assurance tests will be performed in solid water using an average value of 1.07 for the solid water‐to‐water factor. The skin‐to‐center dose ratio measurements support the Monte Carlo‐based values within 5.0% agreement. For the treatment separation range of 4 cm to 8 cm, the change in center dose would be <1.0% for all applicators when using a compressed pad of 0.2 cm to 0.3 cm. The tests performed ensured that all treatment components of the AccuBoost system are functional and that a treatment plan can be delivered with acceptable accuracy. Based on the commissioning results, a quality assurance manual and guidance documents for clinical use were developed. PACS numbers: 87.55.Qr, 87.56.Da, 87.90.+y

Use of customized intraoral mold high-dose-rate brachytherapy in the treatment of oral cavity cancer in an elderly patient

Head and neck (HN) cancers account for approximately 53,000 cases per year in the United States, with a median age of 60 years at diagnosis.1 Because of the growing age of the population, the incidence of oral cavity or pharyngeal cancers in adults ≥65 years is projected to increase from 19,000 in year 2010 to 31,000 in 2030. Treatment of elderly patients above age 85 can be challenging because of associated comorbidities, complications, and social conditions. According to a Surveillance, Epidemiology, and End Results database analysis of over 2500 patients with HN cancers, age was not an independent prognostic factor and there is no statistical difference in overall survival or disease-free survival after correction for stage.2 However, elderly patients may experience more toxicity from radiation treatment including dermatitis, mucositis, and xerostomia. Moreover, patients with comorbidities will have increased risks of posttreatment complications and selection and modification of treatment is important in this group of patients.3,4

Hypofractionated Radiation Therapy for Localized Prostate Cancer: An ASTRO, ASCO, and AUA Evidence-Based Guideline

PURPOSE The aim of this guideline is to present recommendations regarding moderately hypofractionated (240-340 cGy per fraction) and ultrahypofractionated (500 cGy or more per fraction) radiation therapy for localized prostate cancer. METHODS AND MATERIALS The American Society for Radiation Oncology convened a task force to address 8 key questions on appropriate indications and dose-fractionation for moderately and ultrahypofractionated radiation therapy, as well as technical issues, including normal tissue dose constraints, treatment volumes, and use of image guided and intensity modulated radiation therapy. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and Society-approved tools for grading evidence quality and recommendation strength. RESULTS Based on high-quality evidence, strong consensus was reached for offering moderate hypofractionation across risk groups to patients choosing external beam radiation therapy. The task force conditionally recommends ultrahypofractionated radiation may be offered for low- and intermediate-risk prostate cancer but strongly encourages treatment of intermediate-risk patients on a clinical trial or multi-institutional registry. For high-risk patients, the task force conditionally recommends against routine use of ultrahypofractionated external beam radiation therapy. With any hypofractionated approach, the task force strongly recommends image guided radiation therapy and avoidance of nonmodulated 3-dimensional conformal techniques. CONCLUSIONS Hypofractionated radiation therapy provides important potential advantages in cost and convenience for patients, and these recommendations are intended to provide guidance on moderate hypofractionation and ultrahypofractionation for localized prostate cancer. The limits in the current evidentiary base-especially for ultrahypofractionation-highlight the imperative to support large-scale randomized clinical trials and underscore the importance of shared decision making between clinicians and patients.

Hypofractionated Radiation Therapy for Localized Prostate Cancer: Executive Summary of an ASTRO, ASCO, and AUA Evidence-Based Guideline

PURPOSE The aim of this guideline is to present recommendations regarding moderately hypofractionated (240-340 cGy per fraction) and ultrahypofractionated (500 cGy or more per fraction) radiation therapy for localized prostate cancer. METHODS AND MATERIALS The American Society for Radiation Oncology convened a task force to address 8 key questions on appropriate indications and dose-fractionation for moderately and ultrahypofractionated radiation therapy, as well as technical issues, including normal tissue dose constraints, treatment volumes, and use of image guided and intensity modulated radiation therapy. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and Society-approved tools for grading evidence quality and recommendation strength. RESULTS Based on high-quality evidence, strong consensus was reached for offering moderate hypofractionation across risk groups to patients choosing external beam radiation therapy. The task force conditionally recommends ultrahypofractionated radiation may be offered for low- and intermediate-risk prostate cancer but strongly encourages treatment of intermediate-risk patients on a clinical trial or multi-institutional registry. For high-risk patients, the task force conditionally recommends against routine use of ultrahypofractionated external beam radiation therapy. With any hypofractionated approach, the task force strongly recommends image guided radiation therapy and avoidance of nonmodulated 3-dimensional conformal techniques. CONCLUSIONS Hypofractionated radiation therapy provides important potential advantages in cost and convenience for patients, and these recommendations are intended to provide guidance on moderate hypofractionation and ultrahypofractionation for localized prostate cancer. The limits in the current evidentiary base-especially for ultrahypofractionation-highlight the imperative to support large-scale randomized clinical trials and underscore the importance of shared decision making between clinicians and patients.

Development of clinically relevant QA procedures for the BrainLab ExacTrac imaging system

Abstract Purpose The aim of this study was to develop Quality Assurance procedures for the BrainLab ExacTrac (ET) imaging system following the TG 142 recommendations for planar kV imaging systems. Materials and Methods A custom‐designed 3D printed holder was used to position the Standard Imaging QCkV‐1 phantom at isocenter, facing the ET X ray tubes. The linacs light field (collimator at 45⁰) was used to position the phantom holder. The ET images were exported to ARIA where geometric distortion was checked. The DICOM images were analyzed in the PIPSpro software. The following parameters were recorded (technique 80 kV/2mAs): spatial resolution (Modulated Transfer Function (MTF) F50/F40/F30), contrast‐to‐noise ratio (CNR), and noise. A baseline was generated for future image analysis. Beam quality and exposure were measured using the Unfors R/F detector. Using a rod holder, the detector was placed at isocenter, facing each ET X‐ray tube. The measurements were performed for all preset protocols ranging from cranial low (80 kV/6.3 mAs) to abdomen high (145 kV/25 mAs). The total exposure was converted to dose. Results and Discussion The image quality parameters were close for the two tubes. A common baseline was therefore generated. The average baseline values (both tubes, both images/tube) were 1.06/1.18/1.30, 1.32, and 67.3 for the MTF F50/F40/F30, noise, and CNR respectively. The procedure described here was used for another 24 sets. Using a positioning template and 3D printed phantom holder, experimental reproducibility has been acceptably high. The measured phantom dimensions were within 1 mm from the nominal values. The measured kV values were within 2% of the nominal values. The exposure values for the two tubes were comparable. The range of total measured dose was 0.099 mGy (cranial low) to 1.353 mGy (abdomen high). Conclusions A reliable process has been implemented for QA of the ET imaging system by characterizing the systems performance at isocenter, consistent with clinical conventions.

What makes for a vibrant medical physics professional society

This issue’s invited Editorial is provided by Per Halvorsen, Associate Editor-in-Chief of the JACMP. It concerns the recent effort to modify the Association’s governance and contains some very perceptive analysis that should prove useful if the AAPM decides to revisit this issue at some future date — Michael Mills, JACMP EIC Those of us who are AAPM members have just witnessed a robust debate about the normally dry topic of Association governance. A proposal for a significant change in the Association’s structure was developed by leaders of the Association with the help of a paid consulting firm, and put to the membership for a vote on By-Laws changes needed to implement the proposed governance change. The discussion leading up to the vote was energetic, with many thoughtful observations. The proposal failed to gain the support of the necessary 2/3rds majority of voting members, despite being the result of a sincere effort by a group of dedicated volunteer members. So, what are the key ingredients for a vibrant medical physics professional society? I posit that three ingredients are crucial: diversity of perspective, grass roots engagement, and fiscal checks and balances. One of the threads in the AAPM governance debate could be described as “experience vs. diversity of perspective”. Experience certainly brings value — and in the context of a professional society, this is typically measured in terms of volunteer service within the organization. A disproportionate focus on volunteer experience as a criterion for Association leadership positions, however, brings an increased likelihood of entrenched priorities leading to a less flexible organization. Without diversity of perspective, the organization risks continuing practices even when they do not best serve the organization or its members. One of the comments in the AAPM discussion used the phrase “constructive turbulence”, which captures the principle quite nicely. For example, the AAPM continued to contract with AIP Publishing respecting journal and society publications for over 4 decades; after opening up for competitive bidding, we now have a contract with one of the leaders in scientific publishing with the potential of realizing significantly more net revenue flowing to the Association. The American College of Medical Physics (ACMP) was formed in part due to frustration over entrenched priorities within the AAPM and the consequent lack of focus on professional-practice issues. The ACMP’s formation motivated the AAPM to become more engaged in professional-practice issues, leading to a more active and productive Professional Council. This Journal was founded during the ACMP’s tenure — its open access model challenged the traditional approach to medical physics publishing and has contributed to a more diverse perspective on the Journals’ business management now that the ACMP’s functions have been assumed by the AAPM. Diversity of perspective, then, is arguably more important than volunteer experience for Board of Directors positions in a medical physics professional society — and I say that as one of the individuals holding the distinction of many years of AAPM volunteer experience. Another comment in the recent AAPM governance debate was: “Governance needs to systematically and structurally enforce the possibility that different points of view can and will be presented.” I agree with this statement. What can be done structurally to ensure that different points of view are presented? This leads to the second crucial ingredient: grass roots engagement. The AAPM’s existing governance structure strongly supports grass roots engagement. The Chapter Representatives to the Board of Directors are selected by their local Chapter members — perhaps the essence of grass roots engagement. And while the Association has a Nominating Committee which makes a good-faith effort to identify strong candidates for leadership positions, it is impossible for a small group of individuals to know all the members of the Association. The result is that the Nominating Committee, however well intentioned (full disclosure: I’m a current member of the Committee), is likely to miss many potentially excellent candidates for such leadership positions. In this context, I believe it is essential to preserve the ability for direct nomination by the membership for certain Board positions — which our current governance allows. In the last round of elections, the Nominating Committee’s slate of candidates for At-Large Board positions consisted entirely of PhD physicists. This was not an intentional bias by the Committee, but we missed the mark in terms of ensuring a sufficiently diverse slate of candidates. The membership corrected this by nominating several, equally well qualified, candidates. Our governance structure ensured grass roots engagement, and for that I am grateful. Finally, fiscal checks and balances. An important principle in this regard, as described in another comment in the AAPM governance debate, is that the organization’s budget should be approved by individuals who do not have a direct role in the use of the allocated funds. Our current governance structure honors this principle. The majority of allocated funds are used by the Councils and their many Committees and Task Groups, and by the AAPM Headquarters