Field-in-field technique for upper abdominal malignancies in clinical radiotherapy.

BACKGROUND: In upper abdominal malignancies (UAM), due to the presence of multiple inhomogeneous tissues, a wedge-based conformal treatment planning results in high-dose regions inside the target volume. AIM: This study was designed to explore the feasibility of using a field-in-field (FIF) technique in different UAM and its efficacy in reducing the high-dose regions. MATERIALS AND METHODS: Twelve patients of UAM (which included malignancies of the gastroesophageal junction, stomach, gall bladder, and pancreas) were selected for this study. Computed tomography (CT) scans were performed and three-dimensional conformal wedge plans were generated for all the cases. The same plan was copied with the wedges removed and a FIF plan was generated. The two plans were compared for mean, maximum, and median doses; dose received by 2% (D2) and 98% (D98) of the target volume; volume receiving> 107% (V > 107%) and < 95% (V Statistical Analysis: Statistical analysis was performed with SPSS, version 10.0. RESULTS: For all the cases, the FIF technique was better than wedge-based planning in terms of maximum dose, D2, V > 107%, and CI; there was a statistically significant reduction in monitor units. With regard to doses to critical structures, there was marginal dose reduction for the kidneys and spinal cord with FIF as compared to wedge-based planning. CONCLUSION: The FIF technique can be employed for UAM in place of wedge-based conformal treatment plans.

Development of an electronic radiation oncology patient information management system.

The quality of patient care is critically influenced by the availability of accurate information and its efficient management. Radiation oncology consists of many information components, for example there may be information related to the patient (e.g., profile, disease site, stage, etc.), to people (radiation oncologists, radiological physicists, technologists, etc.), and to equipment (diagnostic, planning, treatment, etc.). These different data must be integrated. A comprehensive information management system is essential for efficient storage and retrieval of the enormous amounts of information. A radiation therapy patient information system (RTPIS) has been developed using open source software. PHP and JAVA script was used as the programming languages, MySQL as the database, and HTML and CSF as the design tool. This system utilizes typical web browsing technology using a WAMP5 server. Any user having a unique user ID and password can access this RTPIS. The user ID and password is issued separately to each individual according to the person's job responsibilities and accountability, so that users will be able to only access data that is related to their job responsibilities. With this system authentic users will be able to use a simple web browsing procedure to gain instant access. All types of users in the radiation oncology department should find it user-friendly. The maintenance of the system will not require large human resources or space. The file storage and retrieval process would be be satisfactory, unique, uniform, and easily accessible with adequate data protection. There will be very little possibility of unauthorized handling with this system. There will also be minimal risk of loss or accidental destruction of information.

Comparison of geometric uncertainties using electronic portal imaging device in focal three-dimensional conformal radiation therapy using different head supports.

AIMS AND OBJECTIVES: To study the geometric uncertainties in the treatment and evaluate the adequacy of the margins employed for planning target volume (PTV) generation in the treatment of focal conformal radiotherapy (CRT) for patients with brain tumors treated with different head support systems. MATERIALS AND METHODS: The study population included 11 patients with brain tumors who were to be treated with CRT. Contrast-enhanced planning CT scan (5-mm spacing and reconstructed to 2 mm) of brain were performed. Five patients were immobilized using neck support only (NR-only) and six patients had neck support with flexion (NRF), the form of immobilization being decided by the likely beam arrangements to be employed for that particular patient. The data was transferred to the planning system (CadPlan) where three-dimensional conformal radiation therapy was planned. Digitally reconstructed radiographs (DRRs) were created for the orthogonal portals with the fixed field sizes of 10 x 10 taken at the isocenter. Treatment verification was done using an amorphous silicon detector portal imaging device for using orthogonal portals and the DRR was used as a reference image. An image matching software was used to match the anatomical landmarks in the DRR and the portal imaging and the displacement of the portals in x, y axis and rotation were noted in the anteroposterior (AP) and lateral images. Electronic portal imaging was repeated twice weekly and an average of 8-14 images per patient was recorded. The mean deviation in all the directions was calculated for the each patient. Comparison of setup errors between the two head support systems was done. RESULTS: A total 224 images were studied in anterior and lateral portals. The patient group with NR-only had 100 images, while the NRF group had 124 images. The mean total error in all patients, NR-only group, and NRF group was 0.33 mm, 0.24 mm, and 0.79 mm in the mediolateral (ML) direction; 1.16 mm, 0.14 mm, and 2.22 mm in the AP direction; and 0.67 mm, 0.31 mm, and 0.96 mm in the superoinferior (SI) direction, respectively. The systematic error (S) in all patients, NR-only group, and NRF group in the ML direction was 0.31 mm, 0.28 mm, and 0.78 mm; 1.29 mm, 0.1 mm, and 2.24 mm in the AP direction; and 0.75 mm, 0.52 mm, and 0.94 mm in the SI direction, respectively. Random error (s) in all patients, NR-only group, and NRF group in the ML direction was 1.25 mm, 1.04 mm, and 1.41 mm; 1.31 mm, 1.36 mm, and 1.28 mm in the AP direction; 1.38 mm, 1.37 mm, and 1.39 mm in the SI direction, respectively. In all patients, the PTV margin with Stroom's formula in the NR-only and NRF group was 1.29 mm and 2.55 mm in the ML, 1.15 mm and 5.38 mm in the AP, and 2.0 mm and 2.85 mm in the SI directions, respectively. CONCLUSION: A PTV margin of 5 mm appears to be adequate; further reduction to 3 mm may be considered based on our results. Errors were significantly higher in the AP direction with NRF when compared to NR-only. Differential PTV margin may therefore be considered, with more margin in the AP and less in other directions, especially with the use of flexion devices.

Unidad de termoluminiscencia. diseño de una interface de operación para computadora personal / Thermoluminiscent reader system

Se describe el proceso de diseño y construcción de una interface para comunicar un equipo de Termoluminiscencia (TLD) con una computadora personal (PC) de modo que la unidad TLD, la interface y la computadora funcionen como un espectrómetro termoluminiscente.

Está correta a dosimetria laser em J/cm2 / Dosimetry in J/cm2: is it correct?

Constataçöes clínicas däo ensejo à revisäo de dosimetria em laser. O artigo mostra que o equacionamento físico está conforme com resultados práticos, indicando cuidados até agora näo levados em consideraçäo na escolha de equipamentos, bem como as densidades de potência e energia influem grandemente nos resultados que se pretende desses aparelhos, bem como na profundidade de penetraçäo do feixe laser