2.A Chengyu Shi, Ph.D

The American Association of Physicists in Medicine (AAPM)1 defines “medical physicist” as “an individual who is competent to independently provide clinical professional services in one or more of the subfields of medical physics.” In addition, AAPM poses two minimum requirements toward credentialing a qualified medical physicist (QMP), a master or doctoral degree, and a national certification, that is, the ABR. Starting the year of 2012, the ABR mandated a 2‐yr residency training, in addition to a degree completion from a CAMPEP‐accredited program, for receiving the certification as a QMP.2 Such stringent requirements resulted from an overall understanding in the field that a QMP carries such a critical responsibility toward patient safety in clinic, and any inadequate training may result in detrimental events. On a contrary, a new job position has emerged in recent years and is given a title “medical physicist assistant (MPA)”. A MPA is defined as “an individual who works under the supervision and responsibility of a QMP and is not currently on a path to become a board‐certified medical physicist”.3 The need of MPAs resulted from the imbalanced supply of eligible medical physicists graduating from residency programs. The number of resident positions is far less than the increased demand of clinical medical physicists.4 At the same time, however, the increasing number of graduating students almost doubles the number of residency positions, which ultimately leaves a large pool of unmatched students. Therefore, it sounds reasonable that the unmatched MP students, and other potential candidates who are not qualified for a QMP, can have a temporary position during their transition, and the MPA is perfect for balancing this need from both ends. However, from a clinical safety point of view, it defeats the high standards that have been posed on the medical physics profession for our goal of patient safety. One may argue that MPA is only to work under the supervision of a QMP. But who is there to monitor and what guidelines are available for clearly defining the word “supervision”? It has been very clear to us that only a graduate from doctorate degree in medical physics (DMP) or a resident program is eligible for the ABR board certification. That entails at least 5 yr of training in medical physics subfields. However, MPA may serve as a shortcut and ultimately hurt the entire profession. Therefore, I herein argue that MPA is not sustainable in our medical physics profession. The reasons are multifold.

First, medical physics is an ever‐evolving field. The knowledge in this field is expanding exponentially and the emerging new technology is fast‐replacing old ones. Looking back 10 yr, we are leaping from three‐dimensional (3D) era to IMRT (intensity‐modulated radiation therapy) and IGRT (image‐guided radiation therapy) era. Looking forward, we may advance to an era with multimodality (such as MRI‐linac, MRI‐PET, etc.) and artificial intelligence (AI). Medical physicists are the core in the success of these advances, which require a medical physicist to be able to fast absorb new knowledge and even lead the development of those technologies. It may be challenging for MPA with limited relevant knowledge and clinical training. DMP/resident trainees have been equipped with dedicated training and knowledge for adapting to the versatile environment in medical physics field and also made themselves ready for the future of medical physics research and development. In addition, medical physicists play an important role in new technology development. For example, the superposition/convolution method was developed by Rockwell Mackie,5 who started his career as a clinical medical physicist in the field. Rotational intensity‐modulated fan‐beam delivery, that is, TomoTherapy, and rotational intensity‐modulated cone‐beam delivery, that is, volumetric‐modulated arc therapy (VMAT), developed between 1993 and 1995,6, 7 was both invented by medical physicists with profound understanding in the field and clinical training. The medical physics profession might become obsolete and easily replaceable if no medical physics pioneers broaden new horizons.

Second, a QMP is needed to run routine clinical duty, while a MPA does not meet the requirement. When the system becomes more complex, the higher standard and requirements will need further clinical training and qualified individuals to confirm that the clinical work is done correctly. Some clinical workload may be shared by an MPA, but it is still QMP's responsibility to double check and sign off. It may not save time for QMP and it may introduce extra risk of making errors if the work was done by an insufficiently trained individual. In addition, beyond the limited tasks that can be completed under the supervision of a QMP, an MPA may have limited ability or motivation to put into field innovation, which may lead to low job satisfaction and fast turnaround. Ultimately, it may take more time for a QMP to train and supervise a fresh MPA instead of saving time on routine clinical work. One may argue that DMP and resident are also temporary positions, yet they have a clear career path to becoming a QMP and the training they received is all substantially counted toward their career development. The career path for them is far more promising. For example, they can obtain ABR board certification, become a clinical physicist, conduct research, and even become a manager or leader in the field. The career path will motivate DMP and residents to improve themselves and provide better work quality to ready them for their next step. The entire medical physics profession has been nurtured and growing with such motivation, while the shortcut to MPA may hurt or kill it.

In conclusion, based on the above‐listed reasons, the DMP/resident program may be more sustainable for the future of the medical physics profession. MPAs may provide important support in the clinic for some centers with staff shortages, but it is a temporary solution and may not be positively serving the medical physics profession in a long run.