PQI Guidelines: Radiation Therapy Physics

Project Examples

1. Category: Accuracy of Analyses and Calculations
2. Category: Safety for Patients, Employees and the Public
3. Category: Practice Guidelines and Standards

These examples address some of the many possibilities for individual PQI projects. Other PQI options are available, including participation in peer review of a self-assessment report or activity within a qualified national project sponsored by a society.

1. Category: Accuracy of Analyses and Calculations
Project: HDR Graphical Optimization

BACKGROUND:
Final optimization in high-dose-rate (HDR) brachytherapy cases often uses "graphical optimization," a procedure that allows the operator to move isodose lines to desired locations. Each move achieves, not only the immediate goal of the move, but also produces other consequences, desirable or not. The final product of the optimization depends on the skill of the operator.

OBJECTIVE:
The results of graphically optimizing cases will be assessed to evaluate each physicist's performance improvement.

PROGRAM:
Each physicist who performs HDR brachytherapy will graphically optimize each of five sequential breast brachytherapy cases. The dose-volume histogram (DVH) generated by each operator for each case will be compared, and techniques to improve the optimization will be discussed.

PROCEDURES:

- Metrics

1. The project will use five consecutive breast brachytherapy cases.
2. Each physicist will graphically optimize the case after geometrical optimization by the computer.
3. The DVH will be generated for each physicist for each case, along with the homogeneity and conformation indices.

- Improvement Plan

1. The physicists will review the cases together, identify those with better or worse results, and discuss how the results were obtained.

- Remeasurement

1. The process will be repeated for the next five consecutive patients.
2. The physicists will determine whether there has been any improvement in the optimization and will prepare a report summarizing their findings.

- Evaluation

The physicists will determine whether the project had a beneficial effect on the practice of graphical optimization and whether repeating the project at intervals would be useful. They will generate a report of their findings.

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2. Category: Safety for Patients, Employees and the Public
Project: Standardizing Physics Chart Checks

BACKGROUND:
Each of the practitioners in the clinic performs external-beam weekly chart checks in a different manner. While all check the calculations, the methods are not always equivalent, nor are the tolerances. In addition, the calculations most likely are the aspect of the treatment with the least probability of error because of the number of checks already performed before the physics check.

OBJECTIVE:
Assess the utility and uniformity of physics chart checks.

PROGRAM:
All physicists will identify the checks they perform when doing a weekly chart check and will list the tolerances they accept. They will also describe how they deal with complicated situations such as wedges on oblique surfaces. The lists will be compared with the comprehensive list in AAPM TG 40 and expanded to include other checks any of the physicists feel should be included. The master list will be used as a checklist when performing physics chart checks for two months, with records kept of agreement between the values planned and those generated during the check. The utility of the checks and of standardizing the check procedures will be analyzed.

PROCEDURES:

- Metrics

1. Each physicist will record the checks performed during chart checks.
2. The lists will be collated and compared with that in AAPM TG 40. A comprehensive list will be generated to include items on the lists.

- Improvement Plan

1. For two months, each physicist will perform all of the listed checks and make a record of the values planned and those generated during the check.
2. At the end of the period, the group will examine the results of the project and the utility of each check.
3. The group will generate a master list of checks to be performed as part of the physics check.

- Remeasurement

1. After six months, each physicist will collect a second set of data.
2. The physicists will determine whether there has been any improvement and will generate a report summarizing their findings

- Evaluation

The physicists will determine whether the project had a beneficial effect on the practice of physics chart checks and whether repeating the project at intervals would be useful. They will generate a report of their findings.

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3. Category: Practice Guidelines and Standards
Project: Standardizing Dose Constancy Testing

BACKGROUND:
Dose constancy testing is typically performed as a part of routine monthly QA and is often carried out by different physicists in the department. Each physicist takes the measurements, documents the procedure, and records the results. It is important that this testing procedure follow the steps outlined in established standards/criteria, such as the AAPM Task Group reports on quality assurance.

OBJECTIVE:
The routine performance of the monthly dose constancy testing is evaluated to ensure compliance with existing standards.

PROGRAM:
The results of the monthly dose constancy testing performed over the course of a year will be examined. Deviations in results among physicists will be compared to the overall deviation across the entire time period. Differing methods among physicists will be examined and used to determine whether any particular approach is more accurate or consistent. The results of this comparison will be shared among the group. Additional training will provided if necessary.

PROCEDURES:

- Metrics

1. Collect dose constancy data for 12 months.
2. Determine the overall standard deviation for all data, along with the standard deviation for each physicist.

- Improvement Plan

1. Compare the methods utilized by each physicist.
2. Establish optimum approach.
3. Review the work habits of any physicist whose methods significantly differ from the established optimum and discuss any changes that might increase accuracy and efficiency. Provide additional training as necessary.

- Remeasurement

1. Each physicist will collect a second set of data after six months.
2. The physicists will determine if there has been an improvement and will generate a report summarizing their findings.

- Evaluation

At annual intervals the diplomate will review the overall progress of the project to determine whether 1) the project is having a positive effect by increasing accuracy of constancy testing and 2) the interventions with the technologists are effective.