Evidence map›Paper›PMID 39031843›Full record

ArticleJournal of applied clinical medical physics2024

Dosimetric impact of intrafraction patient motion on MLC-based 3D-conformal spatially fractionated radiation therapy treatment of large and bulky tumors.

Josh Misa, Alex Volk, Mark E Bernard, William St Clair, Damodar Pokhrel

Abstract readEvaluation Study
In one paragraph

Article in Journal of applied clinical medical physics, 2024. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

Who cites it

4 citing papers in PubMed.

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4 · The record

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PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Josh MisaDepartment of Radiation Medicine, Medical Physics Graduate Program, University of Kentucky, Lexington, Kentucky, USA.
Alex VolkDepartment of Radiation Medicine, Medical Physics Graduate Program, University of Kentucky, Lexington, Kentucky, USA.
Mark E BernardDepartment of Radiation Medicine, Medical Physics Graduate Program, University of Kentucky, Lexington, Kentucky, USA.
William St ClairDepartment of Radiation Medicine, Medical Physics Graduate Program, University of Kentucky, Lexington, Kentucky, USA.
Damodar PokhrelDepartment of Radiation Medicine, Medical Physics Graduate Program, University of Kentucky, Lexington, Kentucky, USA.ORCID https://orcid.org/0000-0003-2694-1047

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

purposeTo evaluate the dosimetric impact on spatially fractionated radiation therapy (SFRT) plan quality due to intrafraction patient motion via multi-field MLC-based method for treating large and bulky (≥8 cm) unresectable tumors.

methodsFor large tumors, a cone beam CT-guided 3D conformal MLC-based SFRT method was utilized with 15 Gy prescription. An MLC GTV-fitting algorithm provided 1 cm diameter apertures with a 2 cm center-to-center distance at the isocenter. This generated a highly heterogeneous sieve-like dose distribution within an hour, enabling same-day SFRT treatment. Fifteen previously treated SFRT patients were analyzed (5 head & neck [H&N], 5 chest and lungs, and 5 abdominal and pelvis masses). For each plan, intrafraction motion errors were simulated by incrementally shifting original isocenters of each field in different x-, y-, and z-directions from 1 to 5 mm. The dosimetric metrics analyzed were: peak-to-valley-dose-ratio (PVDR), percentage of GTV receiving 7.5 Gy, GTV mean dose, and maximum dose to organs-at-risk (OARs).

resultsFor ±1, ±2, ±3, ±4, and ±5 mm isocenter shifts: PVDR dropped by 3.9%, 3.8%, 4.0%, 4.1%, and 5.5% on average respectively. The GTV(V7.5) remained within 0.2%, and the GTV mean dose remained within 3.3% on average, compared to the original plans. The average PVDR drop for 5 mm shifts was 4.2% for H&N cases, 10% for chest and lung, and 2.2% for abdominal and pelvis cases. OAR doses also increased. The maximum dose to the spinal cord increased by up to 17 cGy in H&N plans, mean lung dose (MLD) changed was small for chest/lung, but the bowel dose varied up to 100 cGy for abdominal and pelvis cases.

conclusionDue to tumor size, location, and characteristics of MLC-based SFRT, isocenter shifts of up to ±5 mm in different directions had moderate effects on PVDR for H&N and pelvic tumors and a larger effect on chest tumors. The dosimetric impact on OAR doses depended on the treatment site. Site-specific patient masks, Vac-Lok bags, and proper immobilization devices similar to SBRT/SRT setups should be used to minimize these effects.

Indexed as

Motion CaptureNeoplasmsRadiation DosageRadiotherapy, ConformalRadiotherapy Planning, Computer-AssistedAlgorithmsComputer SimulationMotionbulky tumorsdosimetric impactintrafraction motionMLC‐based SFRTsetup error

Identifiers

PMID39031843
PMCPMC11492359

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.