CivaStrings can be provided with different source strengths. Because the location of the continuous sources can be readily identified on post-implant CT images, plans can be constructed using multiple source strengths with confidence that post-implant identification and dosimetry will be straightforward.

A model CivaString pre-plan employs a regular pattern of multiple interior and peripheral sources. For small prostates, two interior and eight peripheral sources provide prescription dose coverage. For large prostates, four interior and 10-12 peripheral sources are used. For intra-operative planning, additional CivaStrings can be provided for further customization. Other novel variations of plans are being ordered that are tailored specifically for the patient.