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Patient Positioning Solutions · Modular Baseplate Family — what the positioning-accuracy literature says.

Five real anchor citations across the workflow the modular baseplate family is bought for — transferring the CT-defined isocentre to the linac (and to MR-sim / MR-Linac for MRgRT) at sub-millimetre indexing precision, across H&N, thorax, pelvis, breast and full-body anatomy. Covers the AAPM TG-176 dosimetric framework, the MR-Linac positioning workflow (< 1 mm systematic error), a MD Anderson study of 3-point customised H&N SRT reirradiation immobilisation (0.0 ± 0.3 mm residual), a multicenter breast-DIBH setup-accuracy dataset (150 patients / 2 269 image pairs across 3 hospitals) and the gross-error patient-safety layer that sits on top of the indexed workflow. Every DOI + journal reference verified; all URLs open-access.

< 1 mmMR-Linac systematic translational setup error (Cuccia 2021)
0.0 ± 0.3 mmH&N SRT residual setup error post-correction (Wang 2016)
2 – 4 %AAPM TG-176 carbon-fibre baseplate dose perturbation
Product specsThermoplastic mask family evidence
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AAPM TG-176 · baseplate dosimetric framework
2 – 4 %
carbon-fibre dose perturbation vs alternatives
TPS
baseplate inclusion in treatment-planning-system MU calc
Skin
skin-dose air-gap trade-off characterised
Peer-reviewed framework endorsed by AAPM. The reference the baseplate family attenuation performance is measured against for planning-system commissioning.
Foundational · TG-1762014
2 – 4 %Carbon-fibre baseplate dose-perturbation range vs alternative head-holder materials. TG-176 also documents air-gap effects (skin dose recovers to 90 % / 62 % at 5 / 15 cm air gap between mask baseplate and posterior skin) — the framework any modular baseplate family is measured against

Dosimetric effects caused by couch tops and immobilization devices — Report of AAPM Task Group 176

Medical Physics 41(6):061501 — Olch, Gerig, Li, Mihaylov, Morgan (AAPM Radiation Therapy Committee)

MR-Linac positioning workflow — Cuccia 2021
< 1 mm
systematic translational error
MR-safe
non-ferromagnetic + no B0 perturbation
CT → MR → MR-Linac
indexed transfer across rooms
The MR-Linac positioning framework the MR-compatible variant of the modular baseplate family plugs into. Same indexed pitch on the MR-sim + MR-Linac; the planning isocentre transfers without laser-alignment mediation.
MR-Linac positioning2021
< 1 mmMulti-centre European review — systematic translational setup error < 1 mm across MR-Linac patient-positioning workflows. Non-ferromagnetic baseplates + coil-compatible indexing are the standard-of-care for MR-Linac positioning; the same modular baseplate transfers from CT-sim to MR-sim to MR-Linac without per-room recalibration

Patient positioning and immobilization procedures for hybrid MR-Linac systems

Radiation Oncology 16:183 (open access) — Cuccia, Alongi, Belka, Boldrini, Hörner-Rieber, McNair, Rigo, Schoenmakers, Niyazi, Slagter, Votta, Corradini

H&N SRT reirradiation setup accuracy — Wang 2016
2.7 ± 1.4 mm
Initial 3D vector (n = 105 sessions)
before robotic-couch correction
vs
0.0 ± 0.3 mm
Residual after correction
per axis; 2.0 mm PTV margin enabled
H&N SRT reirradiation2016
2.7 → 0.0 mmInitial translational 3D vector 2.7 ± 1.4 mm, corrected to 0.0 ± 0.3 mm after robotic-couch adjustment across 21 patients / 105 treatment sessions. Intrafractional motion 0.9 ± 0.6 mm; 2.0 mm PTV margin achievable for stereotactic reirradiation. The customised 3-point immobilisation shows what modern indexed-baseplate workflows deliver

Improved setup and positioning accuracy using a three-point customized cushion / mask / bite-block immobilization system for stereotactic reirradiation of head and neck cancer

Journal of Applied Clinical Medical Physics 17(3):180 – 189 (open access) — Wang, Wang, Tung, Dimmitt, Wilson Dimmitt, Wong, Edson, Garden, Rosenthal, Fuller, Gunn, Takiar, Wang, Luo, Yang, Wong, Phan (MD Anderson)

Breast DIBH multicenter setup accuracy — Laaksomaa 2024
150
patients across 3 hospitals
2 269
image pairs analysed
2 – 11 mm
Van Herk PTV margin range (structure-dep.)
Multi-institutional dataset validates the breast-board + arm-support-baseplate setup for locoregional whole-breast + lymph-node treatment under DIBH. Anchors the breast-board variant of the baseplate family.
Breast DIBH · multicenter2024
2 269 pairs · 3 hosp150 breast-cancer DIBH patients across three hospitals; 2 269 image pairs analysed. Cranio-caudal breath-hold levels ranged 1.3 ± 2.0 mm to 3.4 ± 2.5 mm across sites; Van Herk PTV margins 2.0 – 10.8 mm depending on structure. Sets the practical envelope for breast + lymph-node radiotherapy setup on the breast-board / arm-support baseplate

Surface-guided radiotherapy systems in locoregional deep-inspiration breath-hold radiotherapy for breast cancer — a multicenter study on the setup accuracy

Reports of Practical Oncology and Radiotherapy 29(2) (open access) — Laaksomaa, Aula, Sarudis, Keyriläinen, Ahlroth, Murtola, Pynnönen, Lehtonen, Björkqvist, Järvinen, Rossi

Automatic patient-safety system — Yan 2013
> 1 cm
real-time gross-setup-error detection threshold
< 1 mm
residual H&N error after auto-correction
± 0.1 mm
short-term system stability
Gross-error prevention is the safety layer that sits on top of the baseplate + IGRT workflow. This paper quantifies what a well-run indexed-positioning + patient-safety-system programme delivers.
Gross-error safety2013
> 1 cmAutomatic patient-safety system detects gross setup errors > 1 cm in real time. Residual H&N errors < 1 mm avg / < 2 mm max after automatic couch motion; abdominopelvic 1.0 – 1.8 mm. Long-term system stability 1.0 ± 0.6 mm over 12 weeks. The safety layer that the indexed baseplate + IGRT workflow depend on for gross-error prevention

Prevention of gross setup errors in radiotherapy with an efficient automatic patient safety system

Journal of Applied Clinical Medical Physics 14(6):4543 (open access) — Yan, Mittauer, Huang, Lu, Liu, Li

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Standards, Regulator + MR-Safety Reading

AAPM TG-176 / TG-179 + ICRU 91 + ESTRO-ACROP + ASTM F2503 + CDSCO Medical Devices Rules reference frameworks the modular baseplate family plugs into. Note: the baseplate is a passive non-radioactive accessory — CDSCO handles the import registration; AERB does not licence the baseplate itself.

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AAPM TG-176 — Dosimetric effects of couch tops + immobilisation devices

Task Group 176 report — framework for attenuation, skin-dose build-up loss and shifted-distribution effects of immobilisation devices in the treatment-planning system.

Reference · AAPMDownload
PDF

AAPM TG-179 — QA for image-guided radiation therapy

IGRT QA framework — CBCT + kV/MV planar imaging verification cadence that the indexed baseplate workflow feeds into.

Reference · AAPMDownload
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ICRU Report 91 — Prescribing, recording and reporting stereotactic treatments with small photon beams

ICRU framework governing stereotactic delivery — GTV / CTV / PTV concepts + geometric-accuracy requirements the baseplate + immobilisation chain is engineered against.

Reference · ICRUDownload
FILE

ESTRO-ACROP — MR-linac immobilisation guidance

ESTRO-ACROP guideline for MR-linac immobilisation and coil-compatible positioning workflow.

Reference · ESTRODownload
FILE

ASTM F2503 — Standard practice for marking medical devices and other items for safety in the MR environment

ASTM MR-safety classification (MR-Safe / MR-Conditional / MR-Unsafe) — the standard the MR-compatible baseplate variants are labelled under.

Reference · ASTMDownload
FILE

CDSCO Medical Devices Rules 2017 (India)

Central Drugs Standard Control Organisation regulatory framework for medical-device import + registration in India. The route Class A passive-accessory positioning devices go through — AERB does not licence non-radioactive positioning baseplates; the AERB licence sits on the linac facility rather than on the accessory itself.

Reference · CDSCODownload

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Six worked treatment-site setups — one indexed-baseplate chassis

Per-site build sheet for H&N IMRT, brain SRS, breast DIBH, pelvic IMRT, lung SBRT and MR-linac transfer — baseplate, headrest, accessory mix and AAPM TG-142 / TG-101 reproducibility targets per workflow.

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Literature Radar · auto-updated daily

Latest positioning + immobilisation research

Fresh peer-reviewed papers on radiotherapy positioning + immobilisation — indexed-baseplate setup reproducibility, MR-Linac positioning workflows, DIBH breast positioning, H&N SRT immobilisation, gross-error prevention. Auto-updated from Europe PMC.

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