 Quality & Safety Considerationsin Stereotactic Radiosurgery and Stereotactic Body Radiation Therapy

Introduction  SRS is well established in cranial neoplasms achieving high local control rates and minimal toxicities.  SBRT is much more recent but results from multi- institutional trials have yielded similar results.  Selected early stage cancers  Oligometastases  Recurrent disease in previously radiated field

SBRT  High degree of anatomic targeting accuracy and reproducibility  High doses of precisely delivered radiation Maximize cell-killing effect Minimize radiation related injury in adjacent normal tissue

SBRT  Special attention and diligence is required for delivery of SBRT due to very small margin of error.

 Errors in measurement of output factors affected 145 patients in Toulouse, France 2006 –  31% 12-mth actuarial rate of trigeminal neuropathy in 32 acoustic neuroma patients overdosed.

Fundamental Elements of SRS and SBRT safety and quality  Immobilization, simulation, treatment planning, delivery and quality assurance is unique in each disease site.

Fundamental Elements of SRS and SBRT safety and quality  Multidisciplinary working environment fostering  Clear communication  Guards against inappropriate interruptions  Careful planning  Thorough risk assessment

Fundamental Elements of SRS and SBRT safety and quality  Thorough review of all resources including staffing levels and skills  Training of all personnel including:  Training in quality management  Safety practices  Program-specific education  Development of quality assurance processes that encompass all clinical and technical program aspects.

Fundamental Elements of SRS and SBRT safety and quality  Development of:  Checklists  Processes for documentation and reporting  Peer review  Regular review of processes and procedures  Updating of clinical guidelines and recommendations  Ongoing needs assessment  Continuous quality improvement

Personnel Considerations  Large commitment of resources required.  Coordinated efforts of properly trained individuals required to evaluate each patient and plan the treatment  Radiation oncologists, medical physicists, dosimetrists, radiation therapists  Other physicians can offer unique subspecialty expertise  Neurosurgeons, oncologic surgeons

Personnel Considerations  Initial training of personnel should be stepwise and via a structured education program.  Training on SBRT technologists including training by vendor(s) is an essential element.

Technical Considerations  Ablative doses of radiation coupled with small margins around CTVs require image guidance and motion management strategy.  Large numbers of non-opposing, often non-axial approaches through complex heterogeneities so doses need to be calculated accurately.  Isocenter placements are complex.

Technical Considerations  Simulation  Custom formed devices that cover a large extent of patient above and below the tumour for immobilization.  Anciliary localization and position monitoring technologies such as surface imaging techniques, implanted radiographic markers specific to tumour sites.  Image guidance strategies such as 4D computed tomography, soft tissue MRI imaging, metabolic information.

Acceptance and commissioning  Acceptance testing is performed in cooperation with equipment vendor to ensure equipment is operating within stated specifications and in compliance with regulatory requirements.

Acceptance and commissioning  Commissioning task includes measurement of radiation characteristics of the machine  Beam data acquisition involving small size of fields may be challenging and require appropriately small detectors.  Independent assessment of small field measurements may be essential and include comparison against published data, verifying data through completely independent set of measurements.  Independent verification of the absolute calibration, utilizing service by the Radiologic Physics Center is essential.

Acceptance and commissioning  Accurate calculation of dose and monitor units must be ensured.  Systematic comparison of calculation and measurement ranging from simple configurations to sophisticated beam arrangements.  Facilitated by site-specific anthropomorphic phantoms.

Acceptance and commissioning  Canadian Association of Provincial Cancer Agencies Stereotactic Radiosurgery – Radiotherapy Standards  ‘It is essential to recognize that commissioning SRS/T techniques involves more than just ensuring that the equipment itself works properly. The whole treatment chain, including the measuring, imaging modalities and treatment planning system must be tested in addition o the delivery unit and SRS/T tools.’

The Quality Assurance Program  Robust QA is crucial and must continuously evolve.  ‘The complexity, variation in individual practice patterns, and continued evolution of stereotactic- related technology can render a static, prescriptive QA paradihm insufficient over time.’

Recommendations for stakeholders  Vendors  Understand the needs and requirements of the clinicians, medical physicists and radiation therapists  Incorporate features and safeguards to assure efficacious and safe operation of their products.  Provide opportunities for specialized training, emphasizing clinical implementation and quality assurance (Not just equipment QA but process QA).  If more than one manufacturer involved, onus is on them to collaborate and ensure compatibility of their systems to ensure safe operation.

Recommendations for stakeholders  Professional organizations  Allocate resources to facilitate proper training in specialized procedures.  Specialized accreditation programs

Recommendations for stakeholders  Government agencies  Centralized registries for event reporting, such as those mandated by law in the United Kingdom, ensure appropriate transparency and provide effective mechanism for all stakeholders to learn from errors.

Summary  Team based approach  Appropriately trained and credentialed specialists.  Significant resources in personnel, specialized technology and implementation time required.  Thorough feasibility analysis needed.  Feasibility and planning discussions needed prior to undertaking new disease sites.

Summary  Acceptance and commissioning protocols and test must explore every aspect of individual and integrated systems.  Comprehensive QA program encompassing all clinical, technical and patient specific treatment aspects.  All stakeholders must demonstrate clear commitment and work closely together to ensure highest level of patient safety and efficacy in SBRT.