MRI-guided biopsy: A valuable procedure alternative to avoid the risks of ionizing radiation from diagnostic imaging methods

We read the well-written article recently published online by Ryan et al. [1] in the Cardiovascular Interventional Radiology Journal. Their study quantified the team radiation exposure during PET/CT-guided interventional procedures and concluded that there was no significant difference compared with the radiation exposure from fluoroscopically guided procedures. The publication of this study is very opportune, and we would like to add some additional comments on the content covered by the authors. The knowledge about cellular and molecular mechanisms acquired in the recent years has developed the concept of functional imaging and improved the understanding of biological behaviour and the tumour development modifying the paradigm of planning procedures. Conventional imaging-guided percutaneous procedures have been well described in the literature with great performance [2– 4]. However, considering the actual context of personalized medicine, the ultimate advanced on oncology treatment has been based on targeted therapy [5]. Additionally, there is strong evidence to support the employment of functional tools, such as PET/CT in the imaging-guided procedures enhancing the performance of percutaneous biopsies and radiofrequency ablation for example [6–8]. Notwithstanding, PET/CT scan is an ionized radiation method reaching high levels of radiation exposure. In even a simple examination, the level of radiation can reach 30 msv of exposure or more depending on the technical conditions under which this exam is performed [9]. We also should consider the cumulative effect of doses, which is not concern for only patients but for the interventional radiologic staff who undergo repeated exposure through ionizing modalities during imaging-guided procedures [10]. The risk of carcinogenesis ionizing radiation has always been a concern of those who work with imagingguided procedures and are not usually adequately protected against ionizing radiation especially when considering women and youth as a part of the team [11]. The development of MRI functional techniques, such as diffusion-weighted imaging (DWI), has changed the conventional morphological characterization and evaluation of malignancies by this method [12]. As the DWI can provide functional information about tissue cellularity and the integrity of cellular membranes, its diagnostic potential in oncology have been demonstrated already for staging, therapeutic planning, and response evaluation [13]. Another new manner to use this sequence is in the planning of imaging-guided procedures [14]. Through commercial software of fusion images available, DWI also can assist in determining the most appropriate diagnostic and therapeutic targets enhancing the performance of these procedures (Fig. 1) as well as minimizing the risks of ionized radiation. M. D. Guimaraes (&) R. Chojniak Department of Imaging, Hospital AC Camargo, Rua Paulo Orozimbo, 726, Aclimacao, Sao Paulo, SP Zip 01535-001, Brazil e-mail: marcosduarte500@gmail.com