Effect of tertiary multileaf collimator (MLC) on foetal dose during three-dimensional conformal radiation therapy (3DCRT) of a brain tumour during pregnancy

Sharma, Dayananda Shamurailatpam; Jalali, Rakesh; Tambe, Chandrashekhar M; Animesh,; Deshpande, Deepak D.

doi:10.1016/j.radonc.2003.10.011

Cited by 23 publications

(7 citation statements)

References 12 publications

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“…Sharma et al report on the treatment of a 30‐year‐old patient with a nonfunctioning pituitary adenoma; planning details are not fully apparent, but the fetal dose was measured to be 2 cGy from the 45 Gy treatment course 24. Horowitz et al reported in 2014 on a 37‐year‐old patient being treated for grade 4 glioblastoma 25.…”

Section: Discussionmentioning

confidence: 99%

Radiation treatment planning and delivery strategies for a pregnant brain tumor patient

Labby

Barraclough

Bayliss

et al. 2018

J Applied Clin Med Phys

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The management of a pregnant patient in radiation oncology is an infrequent event requiring careful consideration by both the physician and physicist. The aim of this manuscript was to highlight treatment planning techniques and detail measurements of fetal dose for a pregnant patient recently requiring treatment for a brain cancer. A 27‐year‐old woman was treated during gestational weeks 19–25 for a resected grade 3 astrocytoma to 50.4 Gy in 28 fractions, followed by an additional 9 Gy boost in five fractions. Four potential plans were developed for the patient: a 6 MV 3D‐conformal treatment plan with enhanced dynamic wedges, a 6 MV step‐and‐shoot (SnS) intensity‐modulated radiation therapy (IMRT) plan, an unflattened 6 MV SnS IMRT plan, and an Accuray TomoTherapy HDA helical IMRT treatment plan. All treatment plans used strategies to reduce peripheral dose. Fetal dose was estimated for each treatment plan using available literature references, and measurements were made using thermoluminescent dosimeters (TLDs) and an ionization chamber with an anthropomorphic phantom. TLD measurements from a full‐course radiation delivery ranged from 1.0 to 1.6 cGy for the 3D‐conformal treatment plan, from 1.0 to 1.5 cGy for the 6 MV SnS IMRT plan, from 0.6 to 1.0 cGy for the unflattened 6 MV SnS IMRT plan, and from 1.9 to 2.6 cGy for the TomoTherapy treatment plan. The unflattened 6 MV SnS IMRT treatment plan was selected for treatment for this particular patient, though the fetal doses from all treatment plans were deemed acceptable. The cumulative dose to the patient's unshielded fetus is estimated to be 1.0 cGy at most. The planning technique and distance between the treatment target and fetus both contributed to this relatively low fetal dose. Relevant treatment planning strategies and treatment delivery considerations are discussed to aid radiation oncologists and medical physicists in the management of pregnant patients.

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Section: Discussionmentioning

confidence: 99%

Radiation treatment planning and delivery strategies for a pregnant brain tumor patient

Labby

Barraclough

Bayliss

et al. 2018

J Applied Clin Med Phys

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“…43,44 Several groups of researchers have estimated fetal dose in the RT of brain tumors during pregnancy. 30,36,[45][46][47][48][49] The fetal-dose estimate for RT of grade 3 astrocytoma without shielding was 0.022 Gy for a tumor dose of 54 Gy for a 6 MV Varian accelerator and 0.49-0.59 Gy for an Asea Brown Boveri accelerator at 8 MV and 16 MV 45 . For a treatment course delivering 65 Gy to brain tumors without shielding equipment, the calculated conceptus dose never exceeded 0.1 Gy.…”

Section: Brain Tumors and Head And Neck Cancersmentioning

confidence: 99%

“…16 Among various components of the fetal dose measured, head leakage was found to be the leading cause contributing 52%, followed by wedge scatter (31%), collimator scatter (14%) and internal scatter (13%). 30 Abdominal shielding can reduce fetal dose by 30-60%. 31 Table 2 shows the total dose, fetal dose, and outcome of pregnant cancer patients undergoing radiotherapy.…”

Section: Radiotherapymentioning

confidence: 99%

“…30 A pregnant patient underwent gamma-knifestereotactic radiosurgery for a solitary metastatic melanoma of the brain. The fetal in vivo dosimetry was measured using TLDs, which was placed at different positions on the patient, corresponding to different locations in the uterus and was in the range 0.0015-0.0031 Gy corresponding to approximately 0.01% of the maximum tumor dose of 25 Gy.…”

Section: Brain Tumors and Head And Neck Cancersmentioning

confidence: 99%

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Radiotherapy and Pregnancy: Together or Alone?

Bakkal¹,

Sayin²

2012

JIUMF

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Organ malformations and mental retardation (the sensitivity is high from 2 to 8 weeks, and 8 to 25 weeks after conception, respectively) are the most serious results of fetal exposure to radiation that are observed after birth and probably arise above a threshold dose of 0.1-0.2 Gy. This threshold dose is not generally reached with curative radiotherapy during pregnancy, because most of the tumors are located sufficiently far from the fetus and that precautions have been taken to protect the unborn child against leakage radiation and collimator scatter. Generally, pregnant women with malignant diseases are advised to delay the radiotherapy until after delivery. If a pregnant patient necessitates radiotherapy the physician should inform the risk of the fetus and the benefits of the mother. Subjects like week of pregnancy, stage of the disease and radiation safety must be discussed in details and the final decision should be taken by the patient. In this review, patients who were exposed to radiation during pregnancy because of radiotherapy and their fetal exposure were discussed.

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“…It is a complex process that uses the two-dimensional (2D) images of the tumor to produce 3D data of the tumor and its surrounding tissues. [ 6 7 8 9 10 ] Treatment planning process is based on focused radiation beams toward the tumor site to reduce patient dose. Radiotherapy is used to damage cancer cells while preserving normal tissues.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Effective Parameters on Quality of Magnetic Resonance Imaging-computed Tomography Image Fusion in Head and Neck Tumors for Application in Treatment Planning

2017

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Background:In radiation therapy, computed tomography (CT) simulation is used for treatment planning to define the location of tumor. Magnetic resonance imaging (MRI)-CT image fusion leads to more efficient tumor contouring. This work tried to identify the practical issues for the combination of CT and MRI images in real clinical cases. The effect of various factors is evaluated on image fusion quality.Materials and Methods:In this study, the data of thirty patients with brain tumors were used for image fusion. The effect of several parameters on possibility and quality of image fusion was evaluated. These parameters include angles of the patient's head on the bed, slices thickness, slice gap, and height of the patient's head.Results:According to the results, the first dominating factor on quality of image fusion was the difference slice gap between CT and MRI images (cor = 0.86, P < 0.005) and second factor was the angle between CT and MRI slice in the sagittal plane (cor = 0.75, P < 0.005). In 20% of patients, this angle was more than 28° and image fusion was not efficient. In 17% of patients, difference slice gap in CT and MRI was >4 cm and image fusion quality was <25%.Conclusion:The most important problem in image fusion is that MRI images are taken without regard to their use in treatment planning. In general, parameters related to the patient position during MRI imaging should be chosen to be consistent with CT images of the patient in terms of location and angle.

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Effect of tertiary multileaf collimator (MLC) on foetal dose during three-dimensional conformal radiation therapy (3DCRT) of a brain tumour during pregnancy

Cited by 23 publications

References 12 publications

Radiation treatment planning and delivery strategies for a pregnant brain tumor patient

Radiation treatment planning and delivery strategies for a pregnant brain tumor patient

Radiotherapy and Pregnancy: Together or Alone?

Evaluation of Effective Parameters on Quality of Magnetic Resonance Imaging-computed Tomography Image Fusion in Head and Neck Tumors for Application in Treatment Planning

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