Margin inclusion or exclusion remains the most critical and controversial aspect of stereotactic radiosurgery (SRS) for metastatic brain tumors. This review aimed to examine the available literature on the impact of margins in SRS of brain metastasis and to assess the response of some medical physicists on the use of these margins. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses method was used to review articles published in PubMed, Embase, and Science Direct databases from January 2012 to December 2022 using the following keywords: planning target volume, brain metastasis, margin, and stereotactic radiosurgery. A simple survey consisting of five questions was completed by ten medical physicists with experience in SRS treatment planning. The results were analyzed using IBM SPSS Statistics version 26.0. Of the 1,445 articles identified, only 38 articles were chosen. Of these, eight papers were deemed relevant to the focus of this review. These papers showed an increase in the risk of radionecrosis, whereas differences in local control were variable as the margin increased. In the survey, the response rate to whether or not to use margins in SRS, a critical question, was 50%. Margin addition increases the risk of radio necrosis. The local control rate varies among treatment modalities and cannot be generalized. From the survey, no consensus was reached regarding the use of these margins. This calls for further deliberations among professionals directly involved in SRS.

Purpose: This study aimed to comprehensively investigate the diverse characteristics of a novel commercial bolus, CLEANBOLUS-WHITE (CBW), to ascertain its suitability for clinical application.
Methods: The evaluation of CBW encompassed both physical and biological assessments. Physical parameters such as mass density and shore hardness were measured alongside analyses of element composition. Biological evaluations included assessments for skin irritation and cytotoxicity. Dosimetric properties were examined by calculating surface dose and beam quality using a treatment planning system (TPS). Additionally, doses were measured at maximum and reference depths, and the results were compared with those obtained using a solid water phantom. The effect of air gap on dose measurement was also investigated by comparing measured doses on the RANDO phantom, under the bolus, with doses calculated from the TPS.
Results: Biological evaluation confirmed that CBW is non-cytotoxic, nonirritant, and non-sensitizing. The bolus exhibited a mass density of 1.02 g/cm³ and 14 shore 00. Dosimetric evaluations revealed that using the 0.5 cm CBW resulted in less than a 1% difference compared to using the solid water phantom. Furthermore, beam quality calculations in the TPS indicated increased surface dose with the bolus. The air gap effect on dose measurement was deemed negligible, with a difference of approximately 1% between calculated and measured doses, aligning with measurement uncertainty.
Conclusions: CBW demonstrates outstanding properties for clinical utilization. The dosimetric evaluation underscores a strong agreement between calculated and measured doses, validating its reliability in both planning and clinical settings.

A new E_n score of the proficiency test (PT) is formulated; it is applicable when a correlation exists between the reference and participant’s values. Based on the uncertainty propagation rule given in ISO/IEC Guide 98-3 (GUM:1995), the E_n score covering the correlation case is newly developed for the PT. The new E_n score will be applied in a future PT organized by the Korea Research Institute of Standards and Science (KRISS) dosimetry team. The new E_n score will enhance measurement traceability and contribute to improving the quality management system of participants in the KRISS PT by avoiding performance underestimation.