Table 3.

Summary of identified studies of manual source displacement in pelvic brachytherapy

Year Authors (citation)	Number of patients	Brachytherapy type	Location of displacements	Magnitude of displacements	Pertinent dosimetric results
2019 Poder et al. 46	20	HDR prostate	three catheters displaced: 3 most heavily weighted 3 closest to urethra & rectum in direction of OAR	CC: ±1–6 mm Transverse: ±1–6 mm AP: ±1–6 mm	Positioning errors most sensitive in CC direction. Positioning errors more sensitive in cranial vs caudal & lateral vs medial directions. 5% change in prostate D90 & V100 with errors of ≈ 3 mm. % failing prostate V100 goal by >5% increases when error >2 mm. % plans failing prostate V100 goal with 3 mm shift per direction: Cranial: 75%; Caudal: 50% Posterior: 0%; Anterior: 5% Medial: 35%; Lateral: 10% Urethra D1cc: >50% fail with 2 mm error in medial, anterior & posterior directions. Rectum D2cc:>50% fail with 5 mm error in posterior direction.
2011 Kolkman-Deurloo et al. 47	5	HDR prostate	All catheters displaced as a single unit Central, most ventral or most dorsal catheter rows displaced	Caudal: 3, 5, 7, 10 mm Caudal: 5 mm	Prostate V100: 91.4% (3 mm), 87.2% (5 mm), 82.6% (7 mm), 75.3% (10 mm). Rectum V80 exceeded tolerance in 80% of cases for all displacements. Urethra V120 increased by a factor ranging from negligible to 26.
2010 Tiong et al. 37	20	HDR prostate	All catheters displaced as a single unit	Caudal: 3, 6, 9, 12 mm	Median TCP: 0.998 (3 mm), 0.964 (6 mm), 0.797 (9 mm), 0.265 (12 mm). Only 75% of 6 mm displacement plans had TCP >95%.
2008 Tanderup et al. 48	20: 10 ring & tandem intracavitary 10 interstitial & intracavitary	HDR cervix	Entire applicator displaced	Intracavitary: CC: ±3 mm,±5 mm Transverse:±3 mm AP: ±3 mm Rotation:±15° (4 mm) Interstitial & intracavitary: CC: ±3 mm,±5 mm	Intracavitary: HRCTV D90: mean change of ≈ 2% / mm for lateral & CC directions, ≈ 1.5% / mm in AP direction. Bladder & rectum D2cc: mean change of 5% / mm in AP direction. Bladder & rectum D0.1cc: mean change of 6% / mm in AP direction. Rotation had limited impact. Interstitial & intracavitary: Sigmoid D0.1cc CC displacement 2.9% / mm ( vs 1.9% / mm intracavitary).

AP, anteroposterior; CC, craniocaudal; D1cc, the minimum dose received by the most irradiated 1 cc of the volume; D0.1cc, the minimum dose received by the most irradiated 0.1 cc of the volume; D2cc, the minimum dose received by the most irradiated 2 cc of the volume; D90, dose delivered to a minimum of 90% of the volume; HDR, high dose rate; HRCTV, high risk clinical target volume; TCP, tumour control probability; V80, volume receiving 80% of prescription dose; V100, volume receiving 100% of prescription dose; V120, volume receiving 120% of prescription dose