Author: Jochen Cammin, Yushi Chang, Mariana Guerrero, Kai Jiang, Narottam Lamichhane, Elizabeth Nichols 👨🔬
Affiliation: Department of Radiation Oncology, UT Southwestern Medical Center, University of Maryland School of Medicine, Department of Radiation Oncology, University of Maryland School of Medicine 🌍
Purpose: Our institution handles a large GYN SYED patient load (5 HDR fractions over 3 days). In recent years, we faced many logistical challenges, such as broken/contaminated catheters, which disrupt the workflow and may cause cancellation of some HDR fractions, leading to suboptimal treatments. Our goal is to develop a contingency plan to address these challenges and complete the patient treatment with minimal impact and disruption.
Methods: We propose a needle-in-needle technique by inserting a 4F catheter into a 6F catheters, commonly used for head-and-neck cases, to deal with broken or contaminated needles. We investigate scenarios with a few or all catheters broken or contaminated. We study geometric (graph paper with catheter, dummies and real source), dosimetric (simulation in eight (8) patient plans adapting a previously developed in-house software), and logistical aspects (using a phantom and SYED template) to determine the impact on dosimetry, to establish appropriate QA processes, and to develop a clinical standard operation procedure.
Results: The geometric measurements show that the 4F catheters inside the 6Fs are shallower by 3mm. The dosimetric impact of shifting a few (1-3) needles and thus their dwell positions by 3mm is very small. If the needle-in-needle technique is used on all needles, the 3mm shift reduces the target D90 by 5.3% on average. Therefore, we recommend assessing the clinical impact when implementing this method with many/all needles contaminated. The logistics of inserting and securing the 4F catheters is simple but may become time-consuming and more challenging if many or all catheters are affected. A QA process is recommended for the time of implementation.
Conclusion: A needle-in-needle technique for HDR-SYED treatments with broken/contaminated catheters has been developed and its geometric, dosimetric, and logistical aspects were investigated. This approach allows to ‘rescue’ treatments that would otherwise need to be replanned or even aborted.