Electronic charting of radiation therapy planning and treatment: Report of Task Group 262.

While most Radiation Oncology clinics have adopted electronic charting in one form or another, no consensus document exists that provides guidelines for safe and effective use of the Radiation Oncology electronic medical records (RO-EMR). Task Group 262 was formed to provide these guidelines as well as to provide recommendations to vendors for improving electronic charting functionality in future. Guidelines are provided in the following areas: Implementation and training for the RO-EMR, acceptance testing and quality assurance (QA) of the RO-EMR, use of the RO-EMR as an information repository, use of the RO-EMR as a workflow manager, electronic charting for brachytherapy and nonstandard treatments, and information technology (IT) considerations associated with the RO-EMR. The report was based on a literature search by the task group, an extensive survey of task group members on their respective RO-EMR practices, an AAPM membership survey on electronic charting, as well as group consensus.

AAPM Task Group 198 Report: An implementation guide for TG 142 quality assurance of medical accelerators.

The charges on this task group (TG) were as follows: (a) provide specific procedural guidelines for performing the tests recommended in TG 142; (b) provide estimate of the range of time, appropriate personnel, and qualifications necessary to complete the tests in TG 142; and (c) provide sample daily, weekly, monthly, or annual quality assurance (QA) forms. Many of the guidelines in this report are drawn from the literature and are included in the references. When literature was not available, specific test methods reflect the experiences of the TG members (e.g., a test method for door interlock is self-evident with no literature necessary). In other cases, the technology is so new that no literature for test methods was available. Given broad clinical adaptation of volumetric modulated arc therapy (VMAT), which is not a specific topic of TG 142, several tests and criteria specific to VMAT were added.

Dosimetry for 131Cs and 125I seeds in solid water phantom using radiochromic EBT film.

PURPOSE: To measure the 2D dose distributions with submillimeter resolution for (131)Cs (model CS-1 Rev2) and (125)I (model 6711) seeds in a Solid Water phantom using radiochromic EBT film for radial distances from 0.06cm to 5cm. To determine the TG-43 dosimetry parameters in water by applying Solid Water to liquid water correction factors generated from Monte Carlo simulations. METHODS: Each film piece was positioned horizontally above and in close contact with a (131)Cs or (125)I seed oriented horizontally in a machined groove at the center of a Solid Water phantom, one film at a time. A total of 74 and 50 films were exposed to the (131)Cs and (125)I seeds, respectively. Different film sizes were utilized to gather data in different distance ranges. The exposure time varied according to the seed air-kerma strength and film size in order to deliver doses in the range covered by the film calibration curve. Small films were exposed for shorter times to assess the near field, while larger films were exposed for longer times in order to assess the far field. For calibration, films were exposed to either 40kV (M40) or 50kV (M50) x-rays in air at 100.0cm SSD with doses ranging from 0.2Gy to 40Gy. All experimental, calibration and background films were scanned at a 0.02cmpixel resolution using a CCD camera-based microdensitometer with a green light source. Data acquisition and scanner uniformity correction were achieved with Microd3 software. Data analysis was performed using ImageJ, FV, IDL and Excel software packages. 2D dose distributions were based on the calibration curve established for 50kV x-rays. The Solid Water to liquid water medium correction was calculated using the MCNP5 Monte Carlo code. Subsequently, the TG-43 dosimetry parameters in liquid water medium were determined. RESULTS: Values for the dose-rate constants using EBT film were 1.069±0.036 and 0.923±0.031cGyU(-1)h(-1) for (131)Cs and (125)I seed, respectively. The corresponding values determined using the Monte Carlo method were 1.053±0.014 and 0.924±0.016cGyU(-1)h(-1) for (131)Cs and (125)I seed, respectively. The radial dose functions obtained with EBT film measurements and Monte Carlo simulations were plotted for radial distances up to 5cm, and agreed within the uncertainty of the two methods. The 2D anisotropy functions obtained with both methods also agreed within their uncertainties. CONCLUSION: EBT film dosimetry in a Solid Water phantom is a viable method for measuring (131)Cs (model CS-1 Rev2) and (125)I (model 6711) brachytherapy seed dose distributions with submillimeter resolution. With the Solid Water to liquid water correction factors generated from Monte Carlo simulations, the measured TG-43 dosimetry parameters in liquid water for these two seed models were found to be in good agreement with those in the literature.

Task Group 142 report: quality assurance of medical accelerators.

The task group (TG) for quality assurance of medical accelerators was constituted by the American Association of Physicists in Medicine's Science Council under the direction of the Radiation Therapy Committee and the Quality Assurance and Outcome Improvement Subcommittee. The task group (TG-142) had two main charges. First to update, as needed, recommendations of Table II of the AAPM TG-40 report on quality assurance and second, to add recommendations for asymmetric jaws, multileaf collimation (MLC), and dynamic/virtual wedges. The TG accomplished the update to TG-40, specifying new test and tolerances, and has added recommendations for not only the new ancillary delivery technologies but also for imaging devices that are part of the linear accelerator. The imaging devices include x-ray imaging, photon portal imaging, and cone-beam CT. The TG report was designed to account for the types of treatments delivered with the particular machine. For example, machines that are used for radiosurgery treatments or intensity-modulated radiotherapy (IMRT) require different tests and/or tolerances. There are specific recommendations for MLC quality assurance for machines performing IMRT. The report also gives recommendations as to action levels for the physicists to implement particular actions, whether they are inspection, scheduled action, or immediate and corrective action. The report is geared to be flexible for the physicist to customize the QA program depending on clinical utility. There are specific tables according to daily, monthly, and annual reviews, along with unique tables for wedge systems, MLC, and imaging checks. The report also gives specific recommendations regarding setup of a QA program by the physicist in regards to building a QA team, establishing procedures, training of personnel, documentation, and end-to-end system checks. The tabulated items of this report have been considerably expanded as compared with the original TG-40 report and the recommended tolerances accommodate differences in the intended use of the machine functionality (non-IMRT, IMRT, and stereotactic delivery).

Concise matrix analysis of point-based prostate targeting for intensity modulated radiation therapy.

Intensity Modulated Radiation Therapy (IMRT) has recently emerged as an effective clinical treatment tool to treat various types of cancers by limiting the external beam dose to the surrounding normal tissue. However, the process of limiting external radiation dose to the tissue surrounding the tumor volume is not a trivial task. Several parameters including tumor volume and inhomogeneity, position and shape of the tumor volume, and the geometrical distribution of the radiation beams directly affect the determination of the external radiation dose. In addition, a major variable in effective delivery of the radiation dose is "set-up error" caused by the changes in patient position. Any changes in the position of the patient affect the geometrical location of the tumor volume and, therefore, need to be accommodated in the delivery of radiation beams during the treatment. This work presents a complete matrix representation required to calculate the three-dimensional rigid body homogeneous transformation matrices corresponding to external beam radiotherapy setup error and subsequent corrections in treatment beam parameters. A new concise orthogonal rotation solution is presented for use with clinical noisy data. Monte Carlo simulations prove the new matrix results are consistently better than the standard inverse solution. The required corrections in beam table, gantry, and collimator angles as function of the planned beam gantry angle are derived. For transformations that include a rotation on the sagittal plane, the required offsets to beam parameters are complex functions of the planned gantry angle but are clearly documented graphically for clinical use. A case study is presented with an error analysis that supports the use of the presented method in a clinical environment. Clinical implementation and evaluation of the presented method with patient data is also included in the paper.

A clinical procedure for case-specific analytical validation of mono-modality image fusion in image guided radiotherapy.

Image guided radiotherapy can be performed by fusing the daily treatment and reference planning computed tomography scans. Decreased errors in patient setup can lead to smaller target margins that significantly improve treatment efficacy and outcome. The purpose of this work is to present a clinical procedure to analytically compute the accuracy of the registration. Accepted techniques such as normalized mutual information intensity based three-dimensional image registration can be validated using a large automated point sample. Without a user independent metric it is not possible to determine effect of the fusion error on the calculated correction in patient setup.

A clinical application of an automated phantom-film QA procedure for validation of IMRT treatment planning and delivery.

To quantify the correlation between planned and delivered intensity-modulated radiation therapy (IMRT) dose distributions, IMRT plans for 37 prostate carcinoma patients were analyzed. IMRT treatment plans were converted into hybrid phantom plans using a commercially available treatment planning system and delivered to a specialized film phantom via a static-tomotherapy technique. The films were analyzed using a commercial film dosimetry system. Hybrid phantom axial dose maps and film images were normalized, registered to one another, and subtracted to calculate the overall relative dose difference throughout the entire film area on a pixel-by-pixel basis. The average percentage of pixels with dose-difference values greater than +/- 3% among analyzed hybrid patient plans was 8.6% +/- 3%. The average percentage of pixels with dose differences greater than +/- 5% was 1.7% +/- 1.0%. The number of pixels with more than +/- 10% dose differences was negligible. An initial subset of hybrid plans was used to develop a quantitative criterion to verify for positional accuracy based on dosimetric verification of intensity map of IMRT plans for prostate patients in our institution. Plans with less than 5% of the pixels outside the +/- 5% dose-difference range were accepted. This method could be implemented for other anatomical sites or treatment planning and delivery systems.

Clearance assurance for stereotactic radiosurgery and radiotherapy.

The nature of stereotactic radiotherapy (SRT)/radiosurgery (SRS) requires the use of oblique non-coplanar beams to avoid critical structures and maximize target coverage. These beams are delivered via a combination of gantry, collimator, and couch rotations. Such beam orientations could result in the gantry colliding with the patient or couch. The outcome can be patient injury, damaged equipment, and unrealized treatment. Our objective in this work was to create a treatment planning tool that utilizes each unique patient geometry to quantify clearance for stereotactic beams. Emphasis was placed on developing a general platform that can completely, yet easily, define any user system. Gantry components were described by providing component dimensions to software that generates thousands of surface points. Table components were described as a combination of boxes and measured surface points. During the treatment planning process isocenter coordinates, patient dimensions and beam orientation were specified. Gantry components were then transformed into the table reference frame. The shortest distance between the gantry and patient or couch was computed and compared to a safety margin. This clearance assurance algorithm was developed in response to the need to reduce patient setup time, and to increase the range of potentially useful beams. The software was verified by measuring minimum gantry-table distances at multiple beam orientations and comparing to calculations. Differences between calculated and measured clearances were on the order of 1 cm. The software enabled the safe delivery of noncoplanar oblique beams that are difficult to visualize. The software was used successfully to assure clearance for 50 patients (366 beams). This useful clinical tool became an integral part of the stereotactic quality assurance protocol at St Luke's-Roosevelt Hospital Center.