Determinação da Concentração de Contraste de Iodo em Mamografia Digital de Dupla Energia

The detection of suspicious masses in mammographic exams are compromised by breast tissue overlapping on the image. The dual energy digital mammography technic uses two exposures with different energies obtaining two mammographic imagens, where their subtraction would cancel part of the overlapping tissue enhancing its visualization. The developing of carcinomas induces angiogenesis, an increase on the vascularization in the region of the lesion. Therefore, with the addition of an intravenous Iodine solution it would accumulate at the carcinoma region generating a contrasted object that would be highlighted by the dual energy technique. In this work we calculated the signals obtained by the detector ( from the two exposures we can fit an inverse function that calculate the mass thickness of Iodine as a function of the signal, providing quantitative data regarded to the Iodine concentration. Comparing the values obtained by calibration data for the mass thickness of Iodine and those obtained from the inverse function we verify that they are equal, showing that the function fits the proposed model for contrasted dual energy digital mammography.FAPEMIG - Fundação de Amparo a Pesquisa do Estado de Minas GeraisTrabalho de Conclusão de Curso (Graduação)A detecção de massas suspeitas em exames mamográficos é comprometida pela superposição de tecido mamário na imagem. A técnica de mamografia digital de dupla energia utiliza duas exposições com energias diferentes obtendo assim duas imagens mamográficas, onde a subtração dessas cancelaria parte do tecido sobreposto na imagem melhorando a visualização. O desenvolvimento de carcinomas induz angiogênese, ou seja, um aumento na vascularização na região da lesão. Logo, com adição de uma solução de Iodo intravenosa esta se acumularia na região do carcinoma gerando um objeto de contraste que pode ser destacado pelo uso da técnica de dupla energia. Neste trabalho, calculamos os sinais obtidos no detector ( referente as duas exposições podemos obter uma função inversa que calcula a espessura mássica de Iodo em função do sinal obtido, fornecendo assim dados quantitativos a respeito da concentração de Iodo. Comparando os valores obtidos por dados de calibração para a espessura mássica de Iodo e os valores obtidos através da função inversa verificamos que estes são iguais, mostrando que a função se adequa ao modelo proposto para mamografia digital contrastada de dupla energia

Deep inspiration breath hold: dosimetric benefits to decrease cardiac dose during postoperative radiation therapy for breast cancer patients

Background: Postoperative radiation therapy (RT) is the standard treatment for almost all patients diagnosed with breast cancer. Even with modern RT techniques, parts of the heart may still receive higher doses than those recommended by clinically validated dose limit restrictions, especially when the left breast is irradiated. Deep inspiration breath hold (DIBH) may reduce irradiated cardiac volume compared to free breathing (FB) treatment. This study aimed to evaluate the dosimetric impact on the heart and left anterior descending coronary artery (LAD) in FB and DIBH RT planning in patients with left breast cancer. Materials and methods: A retrospective cohort study of women diagnosed with left-sided breast cancer submitted to breast surgery followed by postoperative RT from 2015 to 2019. All patients were planned with FB and DIBH and  hypofractionated dose prescription (40.05 Gy in 15 fractions). Results: 68 patients were included in the study. For the coverage of the planned target volume evaluation [planning target volume (PTV) eval] there was no significant difference between the DIBH versus FB planning. For the heart and LAD parameters, all constraints evaluated favored DIBH planning, with statistical significance. Regarding the heart,  median V16.8 Gy was 2.56% in FB vs. 0% in DIBH (p < 0.001); median V8.8 Gy was 3.47% in FB vs. 0% in DIBH (p < 0.001) and the median of mean heart dose was 1.97 Gy in FB vs. 0.92 Gy in DIBH (p < 0.001). For the LAD constraints D2% < 42 Gy, the median dose was 34.87 Gy in FB versus 5.8  Gy in DIBH (p < 0.001); V16.8 Gy < 10%, the median was 15.87% in FB versus 0% in DIBH (p < 0.001) and the median of mean LAD dose was 8.13Gy in FB versus 2.92Gy in DIBH (p < 0.001). Conclusions: The DIBH technique has consistently demonstrated a significant dose reduction in the heart and LAD in all evaluated constraints, while keeping the same dose coverage in the PTV eval