The dosimetry of small fields has become tremendously important with the advent of intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery, where small field segments or very small fields are used to treat tumors. With high dose gradients in the stereotactic radiosurgery or radiotherapy treatment, small field dosimetry becomes challenging due to the lack of lateral electronic equilibrium in the field, x-ray source occlusion, and detector volume averaging. Small volume and tissue-equivalent detectors are recommended to overcome the challenges. With the lack of a perfect radiation detector, studies on available detectors are ongoing with reasonable disagreement and uncertainties. The joint IAEA and AAPM international code of practice (CoP) for small field dosimetry, TRS 483 (Alfonso et al., 2017) provides guidelines and recommendations for the dosimetry of small static fields in external beam radiotherapy. The CoP provides a methodology for field output factor (FOF) measurements and use of field output correction factors for a series of small field detectors and strongly recommends additional measurements, data collection and verification for CyberKnife (CK) robotic stereotactic radiotherapy/radiosurgery system using the listed detectors and more new detectors so that the FOFs can be implemented clinically. The present investigation is focused on using 3D gel along with some other commercially available detectors for the measurement and verification of field output factors (FOFs) for the small fields available in the CK system. The FOF verification was performed through a comparison with published data and Monte Carlo simulation. The results of this study have proved the suitability of an in-house developed 3D polymer gel dosimeter, several commercially available detectors, and Gafchromic films as a part of small field dosimetric measurements for the CK system.
Student retention intention remains a concern for higher education systems worldwide and is relevant to institutional sustainability and Sustainable Development Goal 4 (SDG 4). Drawing on Human Capital Theory (HCT) and Expectancy-Value Theory (EVT), this study examines the direct and indirect associations between perceived quality teaching and student retention intention through students' self-reported knowledge, skills, competencies and student loyalty. Cross-sectional survey data were collected from 395 final-year students across Pakistani universities using a multistage sampling approach, with institutions selected through stratified random sampling and participants recruited via convenience sampling. The proposed relationships were examined using structural equation modeling with SmartPLS 4. The results indicate that perceived quality teaching is positively associated with student retention intention, both directly and indirectly through students' knowledge, skills, and competencies and student loyalty. Significant indirect associations were identified through each mediator separately and through the proposed serial mediation pathway. These findings highlight the relevance of considering students' perceived capability development and institutional attachment together when examining retention intention. HCT provides a rationale for the relationship between perceived teaching quality and students' knowledge, skills, competencies, while EVT offers an interpretive perspective; however, expectancy of success and subjective task value were not directly measured. The cross-sectional design also precludes conclusions about temporal ordering or causality. Practically, the findings suggest that faculty development, student-centered pedagogies, digitally supported teaching, and curriculum alignment with labor market needs merit consideration in institutional quality assurance. The findings provide context-specific evidence from Pakistani higher education (HE) and are relevant to SDG 4 through their focus on perceived teaching quality and students' intentions to continue their studies. They do not establish effects on actual retention or broader educational outcomes.