Here is the design of a clinical trial:

Official Title: A Phase III Randomized-controlled, Single-blind Trial to Improve Quality of Life With Stereotactic Body Radiotherapy for Patients With Painful Bone Metastases

Included conditions:
- Metastasis to Bone
- Radiotherapy
- Neoplasm Metastasis

Study Armgroups:
- {'label': 'Single fraction of 8 Gy', 'type': 'ACTIVE_COMPARATOR', 'description': 'The current standard treatment will be prescribed, i.e. a 3D-conformal radiotherapy of a single fraction dose of 8.0 Gy to the metastasis with a planning target volume (PTV) margin for set-up and positioning uncertainties of 1 cm. This can be performed at any linear accelerator.', 'interventionNames': ['Radiation: 3D-conformal radiotherapy']}
- {'label': 'Single fraction of 20 Gy', 'type': 'EXPERIMENTAL', 'description': 'Within the framework of stereotactic body radiotherapy, a single fraction dose of 20.0 Gy will be delivered to the metastasis using a PTV margin of 3-5 mm based on high-precision image-guided radiotherapy (IGRT). Therefore, only linear accelerators with the European Organization for Radiotherapy \\& Oncology advisory committee on radiation oncology practice (ESTRO-ACROP) specifications for SBRT can be accepted. A risk-adapted approach will be applied, aiming for the highest possible dose no less than 16 Gy, while respecting the tolerances of critical organs at risk (e.g. spinal cord, cauda equina, brainstem etc.).', 'interventionNames': ['Radiation: Stereotactic body radiotherapy']}

Interventions:
- {'type': 'RADIATION', 'name': 'Stereotactic body radiotherapy', 'description': 'Treatment will be prescribed to the periphery of the target, i.e. 80% of the dose should cover 95% of the PTV. The organ at risk (OAR) dose constraints will be in accordance with the recommendations from the report of the American Association of Physicists in Medicine (AAPM) task group 101. Image-guidance will consist of cone-beam CT in combination with 6 degrees of freedom corrections using robotic couch.', 'armGroupLabels': ['Single fraction of 20 Gy']}
- {'type': 'RADIATION', 'name': '3D-conformal radiotherapy', 'description': 'In the standard setting, 95% of the PTV should receive 95% of the prescribed dose while near maximum dose (Dnear-max) in the PTV should not exceed 107%. Image-guidance will consist of portal images showing the relevant bony anatomy.', 'armGroupLabels': ['Single fraction of 8 Gy']}

Primary Outcomes:
- {'measure': 'Pain response', 'description': 'Pain response at the treated index site at 1 month after radiotherapy (RT), as defined by the consensus statement.', 'timeFrame': '4 weeks after RT visit'}

Please estimate the sample size based on the assumption: 
Type I error of 0.05, power of 0.8, and a drop-out rate of 10%.
Sample size calculation
          Currently, a complete pain response rate of maximum 25% after a single fraction of 8.0âGy can be assumed [1â3]. With 116 patients, we can show a statistically significant increase to 50% in complete pain response (with Type I error of 0.05 and power of 0.8). Assuming a drop-out rate of 10%, we need to include 126 patients.