A Small Tolerance for Catheter Displacement in High–Dose Rate Prostate Brachytherapy is Necessary and Feasible

Prostate external beam radiotherapy combined with high-dose-rate brachytherapy: dose-volume parameters from deformably-registered plans correlate with late gastrointestinal complications

“…The patient criteria and treatment methodology for the RADAR trial have previously been detailed [14,15]. Aspects of the combined EBRT/ HDR treatment process have previously been described [16]. The four-field EBRT plans for a prescription dose of 46 Gy in 23 daily fractions were created in the Elekta XiO treatment planning system (Elekta AB, Stockholm, Sweden).…”

“…A variety of methods have been used to estimate interfraction motion in prostate HDR [16,54] and the subsequent impact on rectum dose parameters for prostate brachytherapy [54,[63][64][65]. Simnor et at.…”

“…[54] calculated that the catheter mean caudal displacements of 7.9 mm and 3.8 mm prior to fractions 2 and 3 were associated with mostly systematic increases to the D 2cc of 0.69 Gy (~6.6 %) and 0.76 Gy (~7.2 %) respectively. For HDR at the institution where patients in this study were treated, the displacement of catheters was checked prior to each of the three fractions using an anterior-posterior radiograph and corrected for using a rigid external holding device as described by Tiong et al [16]. The catheter mean caudal displacements after this advancement process were reported as 1.7 mm, 1.1 mm and 0.8 mm for fractions 1, 2 and 3 respectively [16].…”

“…For HDR at the institution where patients in this study were treated, the displacement of catheters was checked prior to each of the three fractions using an anterior-posterior radiograph and corrected for using a rigid external holding device as described by Tiong et al [16]. The catheter mean caudal displacements after this advancement process were reported as 1.7 mm, 1.1 mm and 0.8 mm for fractions 1, 2 and 3 respectively [16]. Consequently, the inter-fraction motion increases to the D 2cc reported by Simnor et al [54] may be appropriate conservative estimates for the inter-fraction motion of HDR catheters that could be expected for this study.…”

External beam radiotherapy plus single-fraction high dose rate brachytherapy in the treatment of locally advanced prostate cancer

“…The single implant technique avoids interfraction movements of non-active needle [35], thus avoiding the risk of errors due to needle displacement that can occur in treatments involving multiple fractions [36][37][38]. Needle displacement can generate geometric variability, which can then require a new CT scan to verify needle depth and may also require a new treatment plan.…”