Chest-wall Surface Dose During Post-mastectomy Radiation Therapy, with and without Nonmagnetic Bolus: A Phantom Study

Abstract Aim: When patients receive radiation therapy for breast cancer, they need to take off their underwear to avoid build-up effects. However, it is a mental burden for female patients to take off their underwear at every fraction of radiation therapy. The purpose of this study was to investigate whether commercially available thin underwear can be worn during radiation therapy for breast cancer. Materials and methods: In this phantom study, we investigated whether commercially available underwear can be worn during radiation therapy for breast cancer using six thin non-disposable brassieres and one disposable paper brassiere. The dose increase rate (ΔD) was calculated by measuring skin doses with or without each brassiere. Results: The mean ΔD values of six non-disposable brassieres were 13.5% (9.0–21.8%), whereas that of disposable ones was 2.0%. Findings: Due to the risk of excessive radiation to the skin, wearing commercially available underwear is not recommended during radiation therapy for breast cancer, but a thin disposable paper brassiere may be safe to be used.

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Evaluation of image quality at the detector’s edge of dedicated breast positron emission tomography

EJNMMI Physics ◽

10.1186/s40658-020-00351-6 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Yoko Satoh ◽

Utaroh Motosugi ◽

Masamichi Imai ◽

Yoshie Omiya ◽

Hiroshi Onishi

Keyword(s):

Image Quality ◽

Chest Wall ◽

Clinical Studies ◽

Breast Imaging ◽

Phantom Study ◽

Breast Lesions ◽

Clinical Images ◽

Dedicated Breast Pet ◽

Pet Ct ◽

Significant Difference

Abstract Background Using phantoms and clinical studies in prone hanging breast imaging, we assessed the image quality of a commercially available dedicated breast PET (dbPET) at the detector’s edge, where mammary glands near the chest wall are located. These are compared to supine PET/CT breast images of the same clinical subjects. Methods A breast phantom with four spheres (16-, 10-, 7.5-, and 5-mm diameter) was filled with 18F-fluorodeoxyglucose solution (sphere-to-background activity concentration ratio, 8:1). The spheres occupied five different positions from the top edge to the centre of the detector and were scanned for 5 min in each position. Reconstructed images were visually evaluated, and the contrast-to-noise ratio (CNR), contrast recovery coefficient (CRC) for all spheres, and coefficient of variation of the background (CVB) were calculated. Subsequently, clinical images obtained with standard supine PET/CT and prone dbPET were retrospectively analysed. Tumour-to-background ratios (TBRs) between breast cancer near the chest wall (close to the detector’s edge; peripheral group) and at other locations (non-peripheral group) were compared. The TBR of each lesion was compared between dbPET and PET/CT. Results Closer to the detector’s edge, the CNR and CRC of all spheres decreased while the CVB increased in the phantom study. The disadvantages of this placement were visually confirmed. Regarding clinical images, TBR of dbPET was significantly higher than that of PET/CT in both the peripheral (12.38 ± 6.41 vs 6.73 ± 3.5, p = 0.0006) and non-peripheral (12.44 ± 5.94 vs 7.71 ± 7.1, p = 0.0183) groups. There was no significant difference in TBR of dbPET between the peripheral and non-peripheral groups. Conclusion The phantom study revealed poorer image quality at < 2-cm distance from the detector’s edge than at other more central parts. In clinical studies, however, the visibility of breast lesions with dbPET was the same regardless of the lesion position, and it was higher than that in PET/CT. dbPET has a great potential for detecting breast lesions near the chest wall if they are at least 2 cm from the edge of the FOV, even in young women with small breasts.

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