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Bone metastases remain a therapeutic challenge because of the diversity of the problems they cause, the relative paucity of data regarding their treatment, and the necessity for management by a multidisciplinary palliative care team. The American College of Radiology convened an Appropriateness Criteria Expert Panel on Radiation Oncology for the treatment of bone metastasis to create representative clinical case scenarios and then rank the appropriate use of treatment modalities as well as the most reasonable radiotherapy dose schema and treatment planning methods. Here we present both the resulting Appropriateness Criteria and the rationale for making these decisions. The treatment recommendations are placed within the larger framework of the role of radiation in palliative care by discussing the efficiency of palliative radiotherapy schedules, cost effectiveness issues, and the need for additional research regarding the proper multidisciplinary care of patients with symptomatic bone metastasis.

The purpose of this work is to evaluate the modeling of carbon fiber couch attenuation properties with a commercial treatment planning system (TPS, Pinnacle3, v8.0d). A carbon fiber couch (Brain-Lab) was incorporated into the TPS by automatic contouring of all transverse CT slices. The couch shape and dimensions were set according to the vendor specifications. The couch composition was realized by assigning appropriate densities to the delineated contours. The couch modeling by the TPS was validated by absolute dosimetric measurements. A phantom consisting of several solid water slabs was CT scanned, the CT data set was imported into the TPS, and the carbon fiber couch was auto-contoured. Open (unblocked) field plans for different gantry angles and field sizes were generated. The doses to a point at 3 cm depth, placed at the linac isocenter, were computed. The phantom was irradiated according to the dose calculation setup and doses were measured with an ion chamber. In addition, percent depth dose (PDD) curves were computed as well as measured with radiographic film. The calculated and measured doses, transmissions, and PDDs were cross-compared. Doses for several posterior fields (0 degree, 30 degrees, 50 degrees, 75 degrees, 83 degrees) were calculated for 6 and 18 MV photon beams. For model validation a nominal field size of 10 x 10 cm2 was chosen and 100 MU were delivered for each portal. The largest difference between computed and measured doses for those posterior fields was within 1.7%. A comparison between computed and measured transmissions for the aforementioned fields was performed and the results were found to agree within 1.1%. The differences between computed and measured doses for different field sizes, ranging from 5 x 5 cm2 to 25 x 25 cm2 in 5 cm increments, were within 2%. Measured and computed PDD curves with and without the couch agree from the surface up to 30 cm depth. The PDDs indicate a surface dose increase resulting from the carbon fiber couch field modification. The carbon fiber couch attenuation for individual posterior oblique fields (75 degrees) can be in excess of 8% depending on the beam energy and field size. When the couch is contoured in Pinnacle3 its attenuation properties are modeled to within 1.7% with respect to measurements. These results demonstrate that appropriate contouring together with relevant density information for the contours is sufficient for adequate modeling of carbon fiber supporting devices by modern commercial treatment planning systems.

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