2024 Dosimetry Great Catch

Expand the GTV… instead of the ITV?

During a course of radiation therapy, the dosimetrist rarely interacts directly with the patient. However, their crucial role in creating a safe and effective plan is underscored with each fraction treated. Dosimetrists collaborate closely with radiation oncologists, physicists and radiation therapists to create a high-quality plan for each patient. This interdisciplinary team approach, combined with continuous quality checks, fosters a culture of safety where all team members feel empowered to ask questions or raise concerns if something seems amiss.

In this RO-ILS event, a dosimetrist mentoring a dosimetry student identified an upstream error in the prescription intent.

• A physician's intent included instructions to create the planning target volumes (PTVs) from the gross tumor volumes (GTVs), with a defined margin.
• The dosimetry student followed the instructions and created the PTVs as instructed.
• The treatment plan was developed. 
• The plan went through peer review with no concerns noted.
• Upon peer review by the dosimetry mentor, it was noticed that the internal target volumes (ITVs) were larger than the PTVs, thus, raising concerns for how the margins were defined. 
• The student and mentor dosimetrist reviewed the intent again and verified that there had been no mention of ITVs.
• Once this was discovered they collaborated with the radiation oncologist to have the intent instructions changed and replanned the patient to account for the full extent of motion. 

Great Catch Dosimetry!

This near miss event highlights some important takeaways:

1. Peer-to-peer review for dosimetrists is extremely helpful in not only identifying errors but improving performance. Regardless of role and years in the field, everyone can benefit from learning from their colleagues and improving the quality of their work. This is why intradisciplinary peer review is an APEx Standard but unfortunately, dosimetrist-to-dosimetrist peer review remains a low performing evidence indicator (13.1.4). The RO-ILS Peer Review Themed Report delves into this topic further and includes another case example demonstrating the benefits of dosimetrist peer review.
2. Strong dosimetry mentors play a significant role in helping train others and raising the bar for quality and safety. These great teachers and advisors set an example and are molding the next generation of dosimetrists into well-rounded team members and productive collaborators. American Association of Medical Dosimetrists (AAMD) offers mentoring opportunities for students, an important service for those new in the field. Individuals who do not currently serve in a formal role such as dosimetry supervisor or mentor should not underestimate their peer-to-peer impact on shaping new graduates into high quality colleagues.
3. The safety culture at a facility must enable everyone, including students and trainees, to ask follow-up questions of physicians and other team members. Asking clarifying questions may shed light on an error, as would have been the case in this event, or serve as a learning opportunity. All staff, regardless of experience, also require proper training. The RO-ILS Training and Education Themed Report includes more RO-ILS events to showcase the importance of proper onboarding, managing students and temporary staff, and ongoing staff competency assessment.
4. While the hardest to implement, system-focused solutions such as forcing functions and automation are the most effective safety intervention. With adoption of standardized naming of targets, technology that indicates when tumor volumes are not as expected (i.e., PTV>ITV>CTV>GTV) are most helpful. Vendor implemented solutions such as these have a far-reaching impact.

Safety Check:

What peer-to-peer review processes are in place for medical dosimetrists at your practice? At your practice, which team member generates the PTV and how is it checked for accuracy?

Medical dosimetrists are key to executing high-quality treatment plans and are integral members of the radiation oncology team. The development of the next generation of dosimetrists is critical for the field, and therefore, all dosimetry mentors and educators need to be applauded for their work in shaping trainees. On National Medical Dosimetrist Day and throughout the year, all dosimetrists should be acknowledged and celebrated for their contributions to patient care.

At the national level, the AAMD is a proud supporter of RO-ILS. Together, the sponsors and supporters enable U.S.-based practices to participate in the RO-ILS program for free, allowing shared learning and quality improvement. RO-ILS thanks dosimetrists and AAMD for their contributions to the program and patient safety.