[Thermal distribution in ablation of squamous cell carcinoma skin tumors using irreversible electroporation]

Irreversible electroporation is a new treatment modality for skin tumors ablation. In order to successful treatment, all of tumoral tissues must be exposed to intense electric field. In addition, the heat that produced during the surgery has adverse effect on recovery procedure. This study was done to evaluate the thermal distribution in ablation of squamous cell carcinoma skin tumors using irreversible electroporation. In this study numerical modeling by finite element was used for determination of electrical and thermal distribution in healthy and tumoral tissues. Three-Dimensional Model was done using MR imaging of patient with squamous cell carcinoma in FEMLAB v3.5a software. Electric field distribution determined using Laplace equation and distribution of thermal damage calculated using bioheat equation and Arrhenius equation. This calculation was done for different geometry parameters of needle and plate electrodes. Thermal damage of first-degree burn was not observed in any cases. However in high voltage, volume with temperature above 43[degree sign]C reach to 10% of tumoral tissue and 3% of healthy tissue. The study show that the voltage applied to the electrodes and the distance between the electrodes can have the greatest impact on the thermal and electrical distributions. Although needle electrode showed better electric coverage in tumoral area. This study showed that it can be possible to select optimized electric and geometric parameter to select electrode for complete tumor ablation, control of thermal damage in tumoral and healthy tissues

Incidence of hypothyroidism after external radiation to thyroid region

In this study we evaluated the incidence of hypothyroidism in patients who received external beam radiation due to cancer, when radiation portals included thyroid gland. This prospective study was conducted from April 2004 to December 2005 among patients with head and neck or breast malignancies who referred to Radiation Oncology Department of Cancer Institute, Imam Khomeini hospital, treated with external beam radiotherapy. All patients received radiation to the thyroid gland. Thyroid function was tested at the beginning of treatment, 3 months and 6 months after the completion of radiotherapy. In all 34 patients were included in the study. The median age of patients was 53 years. Eighteen patients were female and 16 were male. All patients received external radiotherapy. They received radiation ranging from 5000 cGY [14 patients 41.2%] to 7400 cGY [1 patient 2.9%] with median of 6000 cGY. Physical examination of thyroid at the beginning of treatment was normal and all of the patients were euthyroid. The results from TSH test showed significant difference at baseline, after 3 and 6 months follow-up [P =0.001]. The findings indicated that none of the patients developed hypothyroidism in a period of six months after completion of radiotherapy. However, it seems that 6 months fallow-up is early for judgment about evaluation of patients for hypothyroidism state and it needs further follow up for minimum of 12 months

Treatment results and epidemiologic factors in oral tongue cancer: analysis of 110 patients in cancer institute of Tehran

Tongue cancer is one of the most common cancers of the oral cavity, excluding lip, and the median age of the patients is approximately 60 years. Treatment results of a total of 110 patients with oral tongue cancer admitted to cancer Institute of Tehran University between 1999-2003 were retrospectively analyzed. The patients were treated by surgery or radiotherapy or chemotherapy in a curative setting. The median age at the time of first visit was 67 years [range 27- 91years].51 patients [46.4%] were female and 59 [53.6%] were male. Primary treatment was surgery in 86 patients [78.2%], radiotherapy alone in 12 patients [10.9%], chemo radiation in 3 patients [2.7%] and chemotherapy [as neo adjuvant therapy] in 8 patients [7.3%]. Median dose of radiation in patients who received radiotherapy was 6000CGY in the range of [5000-7500 CGY]. Median of follow-up of patients was 10 months in range of [1-78] months. Local and loco-regional recurrence remains a major clinical problem in oral cavity tumors. Additional studies and detailed analysis of the selection criteria and treatment outcomes across trials are needed to define the best treatment modalities