Breast cancer normal tissue complication modelling and parameter uncertainties

ABSTRACT: External radiation treatment (ERT) is one of the treatment methods against breast cancer. As all therapies, radiation is linked with side effects. Utmost goal during the treatment with radiation is to maximize the benefit for the patient (efficacy of the treatment) while sparing other vital organs from radiation that could lead to organ’s toxicity. The assessment of the overall benefit of a radiation treatment can be modelled with the help of linear quadratic model. That model simulates the cell killing for a specific type of cell (each cell cancerous or healthy has different properties: radiosensitivity, proliferation) under a given radiation prescription and schema. With the help of modelling, oncologists and medical physicists can simulate and predict the outcome of a radiation treatment schema

Measurement of body composition in cancer patients using CT planning scan at the third lumbar vertebra

OBJECTIVE: the main objective was to assess body composition in terms of skeletal muscle index (SMI), myosteatosis, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and intermuscular adipose tissue (IMAT) as an adjunct of information provided by radiotherapy CT planning scan. MATERIAL AND METHODS: a sample of 49 patients with lung and digestive cancers underwent a CT scan for radiotherapy treatment, which included measurements at the L3 region. Images were analyzed with a radiotherapy contouring software, using different Hounsfield Unit (HU) settings. Cross-sectional areas (cm2) were automatically computed by summing tissue pixels and multiplying by pixel surface area. Low SMI (cm2/m2) and muscle density (HU) were determined according to the recently established cut-off points. RESULTS: the prevalence of low SMI was detected in 46.94% of patients, being present in 8 women, 4 men with BMI < 25 kg/m2, and 11 men with BMI ≥ 25 kg/m2. The average mean skeletal attenuation of total skeletal muscle area was 29.02 (± 8.66) HU, and myosteatosis was present in 13 women (81.25%) and 31 men (93.94%). Mean SAT was 131.92 (± 76.80) cm2, mean VAT was 133.19 (± 85.28) cm2, and mean IMAT was 11.29 (± 12.86) cm2. CONCLUSION: skeletal muscle abnormalities are frequently present in cancer patients and a low SMI may also exist even in the presence of overweight. As CT scans are an important tool at any radiation oncology department, they could also be used to offer highly sensitive and specific information about body composition, as well as to detect early malnutrition before starting radiotherapy treatment

Planificación de tratamientos radioterápicos con intensidad modulada basados en la perspectiva de la anatomía que tiene el haz para su conformación y fluencia

Basándonos en la hipótesis de este trabajo se pretenden obtener tratamientos de IMRT mediante una planificación alternativa más económica desde el punto de vista de la dosis integral al paciente y de los recursos disponibles. Para alcanzar este propósit