Dosimetric impact of applying a model-based dose calculation algorithm for skin cancer brachytherapy (interventional radiotherapy)

Retrospective Dosimetric Comparison of HDR Interventional Radiotherapy (Brachytherapy) Versus Planning with VMAT and Electron Beam Therapy for Non-Melanoma Skin Cancer Treatment

This study compares dosimetric outcomes of high-dose-rate (HDR) interventional radiotherapy (IRT) using Iridium-192, Volumetric Modulated Arc Therapy (VMAT), and electron beam therapy for non-melanoma skin cancer (NMSC). A retrospective analysis of 25 patients showed that IRT provided a significantly higher mean dose to the clinical target volume (CTV) compared to VMAT and electron beam therapy. IRT and VMAT had comparable V95%CTV coverage, whilst electron therapy was less feasible for large CTVs. IRT delivered higher surface doses while minimizing deep tissue exposure compared to partial arc VMAT. Our findings support IRT for personalized and effective NMSC treatment.

On the impact of improved dose calculation accuracy in clinical treatment planning for superficial high-dose-rate brachytherapy of extensive scalp lesions

TG-43-based dose calculations disregard tissue heterogeneities and finite scatter conditions, prompting the introduction of model-based dose calculation algorithms (MBDCAs) to improve accuracy in high-dose-rate (HDR) brachytherapy. This study evaluated the effectiveness of MBDCAs over TG-43 in HDR 192Ir brachytherapy of extended scalp lesions. Treatment planning dose calculations were compared with Monte Carlo (MC) data. TG-43 exhibited a dose overestimation ranging from 10% to 23% as the distance from the implant increased, while a better agreement from 2% to 6% was observed between the MBDCA and MC, supporting the adoption of MBDCAs for dose calculations in broad scalp lesions.

3D technique in superficial brachytherapy: New attitude in old field of mycosis fungoides

A case report of non-classical treatment choice for mycosis fungoides (MF) presented on the left upper eyelid and forehead. Superficial brachytherapy using 3D technique was prescribed to preserve the lens's functionality, and successfully eliminate malignant lesion. Treatment was conducted with high-dose-rate (HDR) brachytherapy using iridium-192 (192Ir) source as a base and Flexitron device as an afterloader. Applicators were immobilized and located near the lesion by manually shaped molds. Doses were calculated using Oncentra treatment planning system (ELEKTA®) with 3D models based on CT scans. A 12-month follow-up showed sustained remission without any late toxicity or recurrence of MF skin lesions on the face. The proposed approach utilizing superficial, mold-based HDR brachytherapy to navigate anatomical challenges is demonstrated to be a clinically effective treatment option for MF of the lower eyelid or other dose-limiting locations.

COMIRI - COMplexity Index of interventional Radiotherapy (brachytherapy) Implants: assessment of procedures based on type, equipment, and team

Historically, several classification systems have been used for brachytherapy, and they were based on the type of clinical purpose, type of implant and timing of the implant, dose-rate, and type of loading for treatment delivery. However, over the last decades, there have been some major technological advancements, including the introduction of image-guidance and possibility to modulate the dose delivered, which have led several authors (in order to highlight the differences between old technique and new approach) to label it in a different way by replacing "brachytherapy" with "interventional radiotherapy". Modern interventional procedures involve several key aspects, which contribute to the complexity of implant phase, such as implant type, imaging used during the procedure, and role of multi-disciplinary team in operating room. By assigning scores to these procedural elements, it is possible to classify the procedure's complexity using a COMIRI classification (COMplexity Index of interventional Radiotherapy Implants). The aim of the COMIRI classification system is to appropriately highlight the need for suitable resources based on the complexity level of different procedures in terms of personnel expertise, equipment availability, and multi-disciplinary teamwork.