Editorial: The role of medical physics in lung SBRT

Stereotactic body radiation therapy (SBRT) has become a standard treatment for non-operable patients with early stage non-small cell lung cancer (NSCLC). In this context, medical physics community has largely helped in the starting and the growth of this technique. In fact, SBRT requires the convergence of many different features for delivering large doses in few fractions to small moving target in an heterogeneous medium. The special issue of last month, was focused on the different physics challenges in lung SBRT. Eleven reviews were presented, covering: imaging for treatment planning and for treatment assessment; dosimetry and planning optimization; treatment delivery possibilities; image guidance during delivery; radiobiology. The current cutting edge role of medical physics was reported. We aimed to give a complete overview of different aspects of lung SBRT that would be of interest to both physicists implementing this technique in their institutions and more experienced physicists that would be inspired to start research projects in areas that still need further developments. We also feel that the role that medical physicists have played in the development and safe implementation of SBRT, particularly in lung region, can be taken as an excellent example to be translated to other areas, not only in Radiation Oncology but also in other health sectors.     

Vaccination therapy in prostate cancer

Radical prostatectomy and radiation therapy provide excellent localized prostate cancer (PC) control. Although the majority of prostate carcinoma is nowadays diagnosed at early stages with favourable risk features, in patients up to 30–40% it recurs within 10 years. Furthermore, the lack of effective therapies, once prostate carcinoma becomes refractory to androgen deprivation, mandates the development of alternative therapeutic options. There is a growing interest in harnessing the potency and specificity of anti-tumour immunity through the generation of fully competent dendritic cells and tumour reactive effector lymphocytes. Several strategies to treat or prevent the development of metastatic PC have been explored in clinical trials and are summarized in this review, considering also the feasibility and safety of these approaches. In some cases clinical responses were achieved showing that vaccine-primed T cells induced anti-tumour activity in vivo. The present findings and perspectives of the immunologic interventions in PC patients will be discussed.     

Metformin and statins: a possible role in high-risk prostate cancer

Aim and backgroundThere is increasing evidence that statins and oral anti-diabetic drugs, such as metformin, can have a favorable role in advanced prostate cancer treatment.Metformin has been shown to inhibit proliferation of tumor cells in vitro and statins inhibit carcinogenesis by suppressing angiogenesis/invasion mechanisms. However, clinical evidence on the protective effect of these drugs is still weak.The purpose of this study is to analyze if these drugs have an impact on Biochemical-Failure-Free-Survival (BFFS) and on Distant-Failure-Free-Survival (DFFS) in localized high-risk prostate cancer.Material and MethodsFrom 2002–2016, 447 patients with histologically confirmed high-risk prostate cancer were retrospectively evaluated. All patients received radiotherapy and androgen deprivation therapy. Biochemical recurrence was determined by the Phoenix criteria and metastatic patients were defined by the presence of radiological metastasis. Survival analysis was performed using the Kaplan-Meier method.Results175 patients were treated with statins (65.3 % with a dose ≤ 20 mg/day) and 70 with metformin (75.7 % with a dose ≤ 1700 mg/day). Median follow-up was 88 months (1–194) with no differences in BFFS and DFFS between metformin and non-metformin patients (77.4 % versus 80 %, p = 0.91 and 89.4 % versus 88.7 %, p = 0.56, respectively). We did not find a statistical difference in BFFS and DFFS in patients taking higher doses of those drugs.ConclusionMetformin and statins were not associated with BFFS or DFFS improvement in our analysis. However, the small number of patients treated with these drugs limits the reliability of the results and prospective studies are needed.     

The medical physics specialization system in Poland

This paper presents the situation of the profession of medical physicists in Poland. The official recognition of the profession of medical physicist in Polish legislation was in 2002. In recent years, more and more Universities which have Physics Faculties introduce a medical physics specialty. At present, there are about 15 Universities which offer such programmes. These Universities are able to graduate about 150 medical physicists per year. In 2002, the Ministry of Health introduced a programme of postgraduate specialization in medical physics along the same rules employed in the specialization of physicians in various branches of medicine. Five institutions, mostly large oncology centres, were selected as teaching institutions, based on their experience, the quality of the medical physics professionals, staffing levels, equipment availability, lecture halls, etc. The first cycle of the specialization programme started in 2006, and the first candidates completed their training at the end of 2008, and passed their official state exams in May 2009. As of January 2016, there are 196 specialized medical physicists in Poland. Another about 120 medical physicists are undergoing specialization.The system of training of medical physics professionals in Poland is well established. The principles of postgraduate training and specialization are well defined and the curriculum of the training is very demanding. The programme of specialization was revised in 2011 and is in accordance with EC and EFOMP recommendations.     

Volumetric modulated arc therapy for prostate cancer patients with hip prosthesis

Aim

To study the use of RapidArc techniques in the treatment of prostate cancer patients with hip prosthesis.

Background

An important aspect of treatment planning is to achieve dose homogeneity inside the planning target volume (PTV). Especially for those patients presenting with hip prosthesis, it becomes a challenging task to achieve dose uniformity inside the PTV.

Materials and methods

Five prostate patients presenting with hip prosthesis who had undergone radical radiotherapy were selected for this study. Depending on the composition of prosthesis, a predefined set of Hounsfield values were assigned to each study set. RapidArc plans were generated on an Eclipse treatment planning system. Two arcs that include clockwise and counter-clockwise arcs were used in all these cases. To avoid beams passing through the prosthesis, a simple structure was defined around it with 1 cm margin and a strict dose constraint applied to the block during VMAT optimization.

Results

The mean D2/D98 ratio of PTV for all the patients was 1.06 ± 0.01. The mean percentage rectum volume receiving 50 Gy, 60 Gy, 70 Gy and 75 Gy for all the patients were 33.1 ± 5.9, 21.7 ± 5.5, 13.8 ± 4.4 and 9.5 ± 3.0, respectively.

Conclusions

This study shows that using a double arc RapidArc technique is a simple and effective treatment method of treating prostate cancer in patients presenting with a hip prosthesis. The definition of a beam avoidance structure encompassing the prosthesis and applying strict dose constraints to it reduces the beam contribution to the prosthesis     

Leadership and mentoring in medical physics: The experience of a medical physics international mentoring program

Mentoring aims to improve careers and create benefits for the participants' personal and professional lives. Mentoring can be an individual or a shared experience for a group, while the mentor’s role remains the same in both models. Mentors should increase confidence, teach, inspire, and set examples, helping the mentees to mould their path, contributing to the pursuit of their personal and professional goals. This study aims to report on the experience of early-career medical physics professionals and postgraduate students participating in a global mentoring program and to assess the impact of this activity on their professional development. The objectives of this mentoring program are to develop leadership roles among young medical physicists and to provide guidance and support. An online questionnaire was administered to the mentee participants. The analysis of their responses is reported in this work and the current status of the programme was examined using a SWOT analysis. In general, the mentoring experience had a positive impact on the mentees. The mentors were found especially helpful in the decision-making situations and in other conflicts that may arise with career development. Additionally, the mentees felt that mentoring contributed to the development of leadership skills required for the job market and assist in personal development. This paper concludes that participation of young medical physicists in a mentoring group program is beneficial to their career and therefore should be encouraged.     

The origins of medical physics

The historical origins of medical physics are traced from the first use of weighing as a means of monitoring health by Sanctorius in the early seventeenth century to the emergence of radiology, phototherapy and electrotherapy at the end of the nineteenth century. The origins of biomechanics, due to Borelli, and of medical electricity following Musschenbroek's report of the Leyden Jar, are included. Medical physics emerged as a separate academic discipline in France at the time of the Revolution, with Jean Hallé as its first professor. Physiological physics flowered in Germany during the mid-nineteenth century, led by the work of Adolf Fick. The introduction of the term medical physics into English by Neil Arnott failed to accelerate its acceptance in Britain or the USA. Contributions from Newton, Euler, Bernoulli, Nollet, Matteucci, Pelletan, Gavarret, d'Arsonval, Finsen, Röntgen and others are noted. There are many origins of medical physics, stemming from the many intersections between physics and medicine. Overall, the early nineteenth-century definition of medical physics still holds today: ‘Physics applied to the knowledge of the human body, to its preservation and to the cure of its illnesses’.     

Choosing between conventional and hypofractionated prostate cancer radiation therapy: Results from a study of shared decision-making

AimTo evaluate patient choice of prostate cancer radiotherapy fractionation, using a decision aid.BackgroundRecent ASTRO guidelines recommend patients with localised prostate cancer be offered moderately hypofractionated radiation therapy after discussing increased acute toxicity and uncertainty of long-term results compared to conventional fractionation.Materials and methodsA decision aid was designed to outline the benefits and potential downsides of conventionally and moderately hypofractionated radiation therapy. The aid incorporated the ASTRO guideline to outline risks and benefits.ResultsIn all, 124 patients with localised prostate cancer were seen from June-December 2018. Median age was 72 (range 50–90), 49.6 % were intermediate risk (50.4 % high risk). All except three patients made a choice using the aid; the three undecided patients were hypofractionated. In all, 33.9 % of patients chose hypofractionation: falling to 25.3 % for patients under 75 years, 24.3 % for patients living within 30 miles of the cancer centre, and 14.3 % for patients with baseline gastrointestinal symptoms. On multivariate analysis, younger age, proximity to the centre, and having baseline gastrointestinal symptoms significantly predicted for choosing conventional fractionation. Insurance status, attending clinician, baseline genitourinary symptoms, work/carer status, ECOG, cancer risk group and driving status did not impact choice. Reasons for choosing conventional fractionation were certainty of long-term results (84 %) and lower acute bowel toxicity (51 %).ConclusionsMost patients declined the convenience of moderate hypofractionation due to potentially increased acute toxicity, and the uncertainty of long-term outcomes. We advocate that no patient should be offered hypofractionation without a thorough discussion of uncertainty and acute toxicity.     

Implementation of intensity modulated radiotherapy for prostate cancer in a private radiotherapy service in Mexico

Intensity modulated radiation therapy (IMRT) allows physicians to deliver higher conformal doses to the tumour, while avoiding adjacent structures. As a result the probability of tumour control is higher and toxicity may be reduced. However, implementation of IMRT is highly complex and requires a rigorous quality assurance (QA) program both before and during treatment. The present article describes the process of implementing IMRT for localized prostate cancer in a radiation therapy department. In our experience, IMRT implementation requires careful planning due to the need to simultaneously implement specialized software, multifaceted QA programs, and training of the multidisciplinary team. Establishing standardized protocols and ensuring close collaboration between a multidisciplinary team is challenging but essential.     

Prostate cancer radiation therapy: A physician’s perspective

Prostate cancer is the second most common cancer in men and a major cause of cancer deaths worldwide. Ionizing radiation has played a substantial role in the curative treatment of this disease. The historical evolution of radiotherapy techniques through 3D-conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and image-guided radiotherapy (IGRT) has allowed more accurate and precise treatments toward significant improvements in the therapeutic ratio. The addition of androgen deprivation therapy has significantly improved overall survival becoming the standard therapy for intermediate- and high-risk disease. Many randomized controlled trials have shown improved local control with dose escalation, and hypofractionated RT has been consolidated with proven efficacy and safe clinical results. However, several questions remain open in the radiotherapeutic management of prostate cancer patients and hopefully ongoing studies will shed light on these uncertainties. More individualized approaches are essential through better prognostic and novel predictive biomarkers of prostate radiotherapy response. Clinicians should critically interpret the evolving technologies in prostate cancer radiotherapy with important optimism but balancing the costs and the actual magnitude of clinical benefit. This article provides an overview of the basic aspects of radiotherapy treatment in localized prostate cancer from a physician’s perspective.     

The status of medical physics in radiotherapy in China

PurposeTo present an overview of the status of medical physics in radiotherapy in China, including facilities and devices, occupation, education, research, etc.Materials and methodsThe information about medical physics in clinics was obtained from the 9-th nationwide survey conducted by the China Society for Radiation Oncology in 2019. The data of medical physics in education and research was collected from the publications of the official and professional organizations.ResultsBy 2019, there were 1463 hospitals or institutes registered to practice radiotherapy and the number of accelerators per million population was 1.5. There were 4172 medical physicists working in clinics of radiation oncology. The ratio between the numbers of radiation oncologists and medical physicists is 3.51. Approximately, 95% of medical physicists have an undergraduate or graduate degrees in nuclear physics and biomedical engineering. 86% of medical physicists have certificates issued by the Chinese Society of Medical Physics. There has been a fast growth of publications by authors from mainland of China in the top international medical physics and radiotherapy journals since 2018.ConclusionsDemand for medical physicists in radiotherapy increased quickly in the past decade. The distribution of radiotherapy facilities in China became more balanced. High quality continuing education and training programs for medical physicists are deficient in most areas. The role of medical physicists in the clinic has not been clearly defined and their contributions have not been fully recognized by the community.     

SBRT for prostate cancer: Challenges and features from a physicist prospective

Emerging data are showing the safety and the efficacy of Stereotactic Body Radiation Therapy (SBRT) in prostate cancer management. In this context, the medical physicists are regularly involved to review the appropriateness of the adopted technology and to proactively study new solutions. From the physics point of view there are two major challenges in prostate SBRT: (1) mitigation of geometrical uncertainty and (2) generation of highly conformal dose distributions that maximally spare the OARs. Geometrical uncertainties have to be limited as much as possible in order to avoid the use of large PTV margins. Furthermore, advanced planning and delivery techniques are needed to generate maximally conformal dose distributions. In this non-systematic review the technology and the physics aspects of SBRT for prostate cancer were analyzed. In details, the aims were: (i) to describe the rationale of reducing the number of fractions (i.e. increasing the dose per fraction), (ii) to analyze the features to be accounted for performing an extreme hypo-fractionation scheme (>6–7 Gy), and (iii) to describe technological solutions for treating in a safe way. The analysis of outcomes, toxicities, and other clinical aspects are not object of the present evaluation.     

Evaluation of combining bony anatomy and soft tissue position correction strategies for IMRT prostate cancer patients

Background

Radiotherapy treatment requires delivering high homogenous dose to target volume while sparing organs at risk. That is why accurate patient positioning is one of the most important steps during the treatment process. It reduces set-up errors which have a strong influence on the doses given to the target and surrounding tissues.

Aim

The aim of this study was to investigate the efficiency of combining bony anatomy and soft tissue imaging position correction strategies for patients with prostate cancer.

Materials and methods

The study based on pre-treatment position verification results determined for 10 patients using kV images and CBCT match. At the same patients’ position, two orthogonal kV images and set of CT scans were acquired. Both verification methods gave the information about patients’ position changes in vertical, longitudinal and lateral directions.

Results

For 93 verifications, the mean values of kV shifts in vertical, longitudinal and lateral directions equaled: −0.11 ± 0.54 cm, 0.26 ± 0.38 cm and −0.06 ± 0.47 cm, respectively. The same values achieved for CBCT matching equaled: 0.07 ± 0.62 cm, 0.22 ± 0.36 cm and −0.02 ± 0.45 cm. Statistically significant changes between the values of shifts received during the first week of treatment and the rest time of the irradiation process were found for 2 patients in the lateral direction and 2 patients in vertical direction among kV results and for 3 patients in the longitudinal direction among CBCT results. A significant difference between kV and CBCT match results was found in the vertical direction.

Conclusions

In clinical practice, CBCT combined with kV or even portal imaging improves precision and effectiveness of prostate cancer treatment accuracy.     

SBRT and extreme hypofractionation: A new era in prostate cancer treatments?

AimRadiation therapy (RT) is a standard therapeutic option for prostate cancer (PC). In the last decades, several innovative technology applications have been introduced. 3-Dimensional conformal RT, volumetric/rotational intensity modulated RT associated or not with image-guided RT, are becoming largely diffused in the treatment of PC.BackgroundConsidering that PC could have a low α/β ratio, similar to late-reacting normal tissues, it could also be highly responsive to fraction size. Thus, the reduction of the number of fractions and the increase of the dose/fraction seem to be reasonable choices in the treatment of this cancer. This review reported the technology evolution, the radiobiological and the clinical data about the role of extreme hypofractionated RT in the treatment approach of PC patients.Materials and methodsMedline search and analysis of published studies containing key words: prostate cancer, radiotherapy, stereotactic radiotherapy.ResultsRecent technological developments, combined with an improved knowledge of the radiobiological models in favor of a high sensitivity of PC to larger fraction sizes are opening a new scenario in its treatment, reporting favorable efficacy and acceptable toxicity, despite short follow-up.ConclusionThus, thanks to technological improvement and the recent radiobiological data, “extreme hypofractionated RT” has been strongly introduced in the last years as a potential solid treatment option for PC.     

Lower urinary tract infections from external beam radiation therapy in prostate cancer: A single institution experience

External beam radiation therapy (EMRT) is effective for the treatment of localized prostate cancer. Lower urinary tract infections (LUTIs) are considered one of the main possible adverse events related to External beam radiation therapy. Here we analyzed the incidence of LUTI during EMRT. Urinary tract infection was assumed when the findings of bacteriuria exceeded 100,000 units/mL, accompanied by specific cystitis symptoms. Among the total 540 analyzed patient, 208 (38.5%) developed a LUTI. E. coli was the main microorganism involved in LUTIs (102, 49.04%) with 8 cases of a combination between E. coli and another germ. In conclusion, a risk of urinary infections in cancer patients treated with pelvic radiotherapy was observed, in order to reduce the use of antibiotic resistance, preventive treatment with non-antibiotic agents 5 are warranted.     

The EU medical device regulation: Implications for artificial intelligence-based medical device software in medical physics

Medical device manufacturers are increasingly applying artificial intelligence (AI) to innovate their products and to improve patient outcomes. Health institutions are also developing their own algorithms, to address specific needs for which no commercial product exists.Although AI-based algorithms offer good prospects for improving patient outcomes, their wide adoption in clinical practice is still limited. The most significant barriers to the trust required for wider implementation are safety and clinical performance assurance .Qualified medical physicist experts (MPEs) play a key role in safety and performance assessment of such tools, before and during integration in clinical practice. As AI methods drive clinical decision-making, their quality should be assured and tested. Occasionally, an MPE may be also involved in the in-house development of such an AI algorithm. It is therefore important for MPEs to be well informed about the current regulatory framework for Medical Devices.The new European Medical Device Regulation (EU MDR), with date of application set for 26 of May 2021, imposes stringent requirements that need to be met before such tools can be applied in clinical practice.The objective of this paper is to give MPEs perspective on how the EU MDR affects the development of AI-based medical device software. We present our perspective regarding how to implement a regulatory roadmap, from early-stage consideration through design and development, regulatory submission, and post-market surveillance. We have further included an explanation of how to set up a compliant quality management system to ensure reliable and consistent product quality, safety, and performance .     

140 years of medical physics in Romania

In 2020 the Romanian College of Medical Physicists celebrated 140 years of medical physics in Romania. The article presents a short historical perspective of medical physics teaching and education in the country, focusing on the current situation and challenges that we are facing in regards to staffing, training and accreditation. While certain aspects concerning the procurement of radiotherapy / medical imaging devices and staffing are improving over the years, others, related to clinical training and education, as well as the national recognition of the profession continue to pose a challenge.     

EFOMP policy statement 16: The role and competences of medical physicists and medical physics experts under 2013/59/EURATOM

On 5 December 2013 the European Council promulgated Directive 2013/59/EURATOM. This Directive is important for Medical Physicists and Medical Physics Experts as it puts the profession on solid foundations and describes it more comprehensively. Much commentary regarding the role and competences has been developed in the context of the European Commission project “European Guidelines on the Medical Physics Expert” published as Radiation Protection Report RP174. The guidelines elaborate on the role and responsibilities under 2013/59/EURATOM in terms of a mission statement and competence profile in the specialty areas of Medical Physics relating to medical radiological services, namely Diagnostic and Interventional Radiology, Radiation Oncology and Nuclear Medicine. The present policy statement summarises the provisions of Directive 2013/59/EURATOM regarding the role and competences, reiterates the results of the European Guidelines on the Medical Physics Expert document relating to role and competences of the profession and provides additional commentary regarding further issues arising following the publication of the RP174 guidelines.     

Medical physics and physics in medicine in Ireland (part 1: 1600–~2000)

Medical physics and other contributions from physics to medicine are relatively well known, if not well documented in Ireland. Less well known are contributions from medicine to the development of physics, which can and do occur. This paper addresses examples of all three. The methods employed include documentary research and interviews with those who share(d) the stage in the area. Documentary evidence for historical aspects of medical physics over the last century are relatively sparse and incomplete. Notwithstanding this, they can and do enable a picture to be built up of how the arrangements in place now have come about, particularly when they are accompanied by mature recollections of the participants.Good critically assessed and accessible sources have been identified covering the seventeenth to nineteenth century material presented. Examples are presented based on the work of significant contributors, each with strong Irish connections, including Robert Boyle, Erwin Schrödinger, Fearghus O'Foghludha, and Edith Stoney the first female medical physicist. Their contributions are striking and continue to be relevant now. The findings provide a rich context and heritage for medical physics in Ireland and in the international community. They will include the contemporary period in a second paper, Part 2 of this study.     

Predicting toxicity in radiotherapy for prostate cancer

This comprehensive review addresses most organs at risk involved in planning optimization for prostate cancer. It can be considered an update of a previous educational review that was published in 2009 (Fiorino et al., 2009).The literature was reviewed based on PubMed and MEDLINE database searches (from January 2009 up to September 2015), including papers in press; for each section/subsection, key title words were used and possibly combined with other more general key-words (such as radiotherapy, dose-volume effects, NTCP, DVH, and predictive model). Publications generally dealing with toxicity without any association with dose–volume effects or correlations with clinical risk factors were disregarded, being outside the aim of the review.A focus was on external beam radiotherapy, including post-prostatectomy, with conventional fractionation or moderate hypofractionation (<4 Gy/fraction); extreme hypofractionation is the topic of another paper in this special issue. Gastrointestinal and urinary toxicity are the most investigated endpoints, with quantitative data published in the last 5 years suggesting both a dose–response relationship and the existence of a number of clinical/patient related risk factors acting as dose–response modifiers. Some results on erectile dysfunction, bowel toxicity and hematological toxicity are also presented.