S1422
Interdisciplinary - Health economics & health services research
ESTRO 2026
availability during linac replacement/times of disaster. By fixing the primary beam and slowly rotating an upright patient, upright radiotherapy lends itself to reduced shielding requirements and mobile units. A fully mobile unit could, for example, follow a regular route to multiple locations, delivering a 5-fraction hypofractionated schedule for common cancers such as breast/lung/prostate. In this study, we investigate the shielding requirements and feasibility of a portable upright radiotherapy system, placed within a standard-size shipping container. Material/Methods: We assume a fixed-beam 6 MV linac, combined with a rotating upright patient positioning system. A 40ft (12.2m) long standard-sized shipping container is considered for multimodal travel. Three shielding design scenarios are presented. Cylindrical (1.75m diameter) shielding close to the patient and linacStandard shielding within the shipping containerSome shielding outside the shipping containerDoses to various points were calculated using the NCRP 151 methodology. Workload was assumed to be 18,000Gy. The primary barrier transmission factor (Bpri) was computed using equation 2.1 from NCRP 151 [3]. The shielding design goal was 1mSv/yr. Secondary shielding requirements were calculated for both patient scatter and linac leakage. For Tenth Value Layers (TVLs), NCRP 151 values were used where available, else values from IAEA report 47 [4] were considered. TVL value of soil was assumed to be 1.5 times that of concrete.
Results: Figure 2 shows the calculated shielding dimensions and weights for each scenario. Scenario 1 has a novel shielding design and delivers a fully shielded unit compatible with transport via European highways (considering a 40 tonne weight limit). Scenario 2 offers a fully shielded portable linac; however, its weight poses challenges for road transport. Scenario 3 is not completely shielded, requiring onsite shielding, but is very lightweight and transportable.
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