Measurements of fetal dose with Mevion S250i proton therapy system with HYPERSCAN

Hopfensperger, Karolyn M; Li, Xing; Paxton, Adam; Sarkar, Vikren; Su, Fan‐Chi Frances; Price, Ryan; Salter, Bill J.; James, Sara St.

doi:10.1002/acm2.13957

Cited by 4 publications

(2 citation statements)

References 23 publications

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“…The findings of our study align with previous research efforts investigating fetal radiation dose exposure during radiotherapy. Hopfensperger et al 34 . utilized the WENDI‐II detector to measure fetal doses, indicating significantly lower exposure levels ranging from 22.5 to 33.2 µSv/Gy compared to photon‐RT.…”

Section: Discussionmentioning

confidence: 99%

Fetal dose assessment in a pregnant patient with brain tumor: A comparative study of proton PBS and 3DCRT/VMAT radiation therapy techniques

Rahimi,

Taylor,

et al. 2024

J Applied Clin Med Phys

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PurposeThe treatment of brain tumors in pregnant patients poses challenges, as the out‐of‐field dose exposure to the fetus can potentially be harmful. A pregnant patient with prior radiation treatment was presented with a brain tumor at our clinic. This work reports on our pre‐treatment study that compared fetal dose exposure between intensity‐modulated proton therapy (IMPT) using pencil beam scanning (PBS) and conventional photon 3D conformal radiation therapy (3DCRT) and volumetric‐modulated arc therapy (VMAT), and the subsequent pregnant patient's radiation treatment.Materials and methodsPre‐treatment measurements of clinical plans, 3DCRT, VMAT, and IMPT, were conducted on a phantom. Measurements were performed using a device capable of neutron detections, closely following AAPM guidelines, TG158. For photon measurements, fetus shielding was utilized. On patient treatment days, which was determined to be proton treatment, shielding was used only during daily imaging for patient setup. Additionally, an in vivo measurement was conducted on the patient.ResultsMeasurements showed that IMPT delivered the lowest fetal dose, considering both photon and neutron out‐of‐field doses to the fetus, even when shielding was implemented for photon measurements. Additionally, the proton plans demonstrated superior treatment for the mother, a reirradiation case.ConclusionThe patient was treated with proton therapy, and the baby was subsequently delivered at full term with no complications. This case study supports previous clinical findings and advocates for the expanded use of proton therapy in this patient population.

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Section: Discussionmentioning

confidence: 99%

Fetal dose assessment in a pregnant patient with brain tumor: A comparative study of proton PBS and 3DCRT/VMAT radiation therapy techniques

Rahimi,

Taylor,

et al. 2024

J Applied Clin Med Phys

Self Cite

View full text Add to dashboard Cite

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“…The measured fetal dose ranged from 0.1 mSv/Gy to a target in the head, to 0.26 mSv/Gy when irradiating the upper abdomen. More recently, Hopfensperger et al 24 measured the fetal dose to a spherical target in the brain using the WENDI detector and an anthropomorphic phantom. The fetal dose was measured at three representative distances – 47, 39.5 and 32 cm – between the isocenter (ie the central point around which the RT gantry is positioned) and the edge of the WENDI detector.…”

Section: Dosimetric Studiesmentioning

confidence: 99%

Challenges and opportunities for proton therapy during pregnancy

Blommaert

Saint-Hubert

Depuydt

et al. 2023

Acta Obstet Gynecol Scand

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During pregnancy, the use of radiation therapy for cancer treatment is often considered impossible due to the assumed associated fetal risks. However, suboptimal treatment of pregnant cancer patients and unjustifiable delay in radiation therapy until after delivery can be harmful for both patient and child. In non‐pregnant patients, proton‐radiation therapy is increasingly administered because of its favorable dosimetric properties compared with photon‐radiation therapy. Although data on the use of pencil beam scanning proton‐radiation therapy during pregnancy are scarce, different case reports and dosimetric studies have indicated a more than 10‐fold reduction in fetal radiation exposure compared with photon‐radiation therapy. Nonetheless, the implementation of proton‐radiation therapy during pregnancy requires complex fetal dosimetry for the neutron‐dominated out‐of‐field radiation dose and faces a lack of clinical guidelines. Further exploration and standardization of proton‐radiation therapy during pregnancy will be necessary to improve radiotherapeutic management of pregnant women with cancer and further reduce risks for their offspring.

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Measurements of fetal dose with Mevion S250i proton therapy system with HYPERSCAN

Hopfensperger

Paxton

et al. 2023

J Applied Clin Med Phys

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To characterize potential dose to the fetus for all modes of delivery (dynamic adaptive aperture, static adaptive aperture, and no adaptive aperture) for the Mevion S250i Proton Therapy System with HYPERSCAN and compare the findings with those of other available proton systems. Materials and Methods: Fetal dose measurements were performed for all three modes of dose delivery on the Mevion S250i Proton therapy system with HYPERSCAN (static aperture, dynamic aperture and uncollimated). Standard treatment plans were created in RayStation for a left-sided brain lesion treated with a vertex field, a left lateral field, and a posterior field. Measurements were performed using WENDI and the RANDO with the detector placed at representative locations to mimic the growth and movement of the fetus at different gestational stages. Results:The fetal dose measurements varied with fetus position and the largest measured dose was 64.7 µSv per 2 Gy (RBE) fraction using the dynamic aperture. The smallest estimated fetal dose was 45.0 µSv per 2 Gy (RBE) at the base of the RANDO abdomen (47 cm from isocenter to the outer width of WENDI and 58.5 cm from the center of the WENDI detector) for the static aperture delivery. The vertex fields at all depths had larger contributions to the total dose than the other two and the dynamic aperture plans resulted in the highest dose measured for all depths. Conclusion:The reported doses are lower than reported doses using a doublescattering system. This work suggests that avoiding vertex fields and using the static aperture will help minimize dose to the fetus.

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Measurements of fetal dose with Mevion S250i proton therapy system with HYPERSCAN

Cited by 4 publications

References 23 publications

Fetal dose assessment in a pregnant patient with brain tumor: A comparative study of proton PBS and 3DCRT/VMAT radiation therapy techniques

Fetal dose assessment in a pregnant patient with brain tumor: A comparative study of proton PBS and 3DCRT/VMAT radiation therapy techniques

Challenges and opportunities for proton therapy during pregnancy

Measurements of fetal dose with Mevion S250i proton therapy system with HYPERSCAN

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