## 1 Introduction  
Non-melanoma skin cancer (NMSC), which includes basal cell carcinoma and squamous cell carcinoma, is the most common type of skin cancer worldwide. The incidence of NMSC has been rising steadily, posing significant challenges for healthcare systems and affecting patient quality of life. Effective treatment strategies are essential to manage this growing burden and improve patient outcomes [1]. Traditional treatment methods for NMSC include surgical excision, cryotherapy, and topical treatments. However, radiotherapy has emerged as a crucial alternative, especially for patients who are not ideal candidates for surgery due to age, comorbidities, or tumor location. Radiotherapy offers the advantage of being non-invasive and can be particularly effective in preserving the cosmetic appearance and function of the treated area [2].  
Recent advancements in radiotherapy techniques have greatly enhanced the precision and efficacy of treatment. High-dose-rate (HDR) interventional radiotherapy (IRT, known also as brachytherapy, BT) using Iridium-192 (\({}^{192}\)Ir) allows for precise dose delivery to the tumor while minimizing radiation exposure to surrounding healthy tissues. Studies have shown that HDR IRT can achieve higher local control rates and better cosmetic outcomes compared to traditional radiotherapy methods [3].  
Another advanced technique, Volumetric Modulated Arc Therapy (VMAT), has gained attention for its ability to deliver highly conformal doses with improved sparing of healthy tissues. VMAT utilizes dynamic modulation of the treatment beam, allowing for efficient dose distribution. Despite its advantages, VMAT requires sophisticated planning and quality assurance processes to ensure optimal outcomes [4].  
Electron beam therapy is another modality used for treating superficial tumors, including NMSC. It offers a distinct dose distribution profile that is beneficial for treating lesions with limited penetration depth. However, its efficacy diminishes for deeper or larger tumors, making it less suitable in certain clinical scenarios [5].  
HDR IRT is known for its ability to deliver a higher mean dose to the clinical target volume (CTV) compared to VMAT and electron beam therapy. This characteristic is crucial for achieving effective tumor control while reducing the risk of side effects [6].  
Despite these technological advancements, optimizing treatment plans remains a complex challenge. Treatment efficacy is influenced by various factors, including tumor size, location, and patient-specific anatomical considerations. Personalized treatment planning is essential to address these variables and improve clinical outcomes [7]. Recent studies emphasize the importance of individualized approaches to radiotherapy, tailoring treatment plans to the unique characteristics of each patient and tumor.  
This study investigates the comparison of HDR \({}^{192}\)Ir IRT with VMAT and electron beam therapy in order to provide critical insights into optimizing treatment plans for NMSC. The goal of this research is to refine treatment methodologies for NMSC, enhance the therapeutic efficacy of each approach, and ultimately support evidence-based decision making in interventional radiotherapy. By comparing these techniques, the study aspires to establish more effective and targeted strategies for managing NMSC, thereby improving patient outcomes and advancing clinical practice.