Retrieves the permissions to access patients information for a role.
            
            
            
            
        
            Parameters
- roleName
 
- A System.String specifying the role name to get its patients access permissions. This value can be null to retrieve permissions assigned for all roles.
 - patientId
 
- The patient ID which permissions are to be retrieved. This value can be null to retrieve permissions for all patients..
 - extraData
 
- User custom data.
 
            
            Return Value
A list of Leadtools.Dicom.Services.DataTypes.RolesPatientsPermission objects specifying the patients permissions for the specified role(s).