Delineation of Margins for the Planning Target Volume (PTV) for Image-Guided Radiotherapy (IGRT) of Gastric Cancer Based on Intrafraction Motion.

Background: Application of the image-guided radiotherapy (IGRT) system for gastric cancer involving daily verification of patient positioning on the treatment machine allows minimisation of geometrical errors as a consequence of intra- and inter-fraction motion. The purpose of this study was to define the intrafraction motion in gastric cancer patients during a treatment session based on the IGRT system and designation of margins around the clinical target volume CTV (internal target volume ITV) necessary to delineate the planning target volume (PTV). Methods: Twenty gastric cancer patients were analysed.

Can we obtain planning goals for conformal techniques in neoadjuvant and adjuvant radiochemotherapy for gastric cancer patients?

Aim: The purpose of this study was to compare conformal radiotherapy techniques used in the treatment of gastric cancer patients. The study is dedicated to radiotherapy centres that have not introduced dynamic techniques in clinical practice.

Background: The implementation of multi-field technique can minimise the toxicity of treatment and improve dose distribution homogeneity in the target volume with simultaneous protection of organs at risk (OaRs).

Protection of organs at risk during neoadjuvant chemoradiotherapy for gastric cancer based on a comparison between conformal and intensity-modulated radiation therapy.

The aim of the present study was to compare the techniques of dynamic intensity-modulated radiation therapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT) in patients with gastric cancer. Implementation of the IMRT technique does not significantly affect the minimum and maximum dose levels in the planning target volume (PTV), but more effectively protects the critical organs. The study group consisted of 25 patients.

Dose distribution in bladder and surrounding normal tissues in relation to bladder volume in conformal radiotherapy for bladder cancer.

Purpose: To estimate bladder movements and changes in dose distribution in the bladder and surrounding tissues associated with changes in bladder filling and to estimate the internal treatment margins.

Methods And Materials: A total of 16 patients with bladder cancer underwent planning computed tomography scans with 80- and 150-mL bladder volumes. The bladder displacements associated with the change in volume were measured.

Could lipid CH2/CH3 analysis by in vivo 1H MRS help in differentiation of tumor recurrence and post-radiation effects?

Purpose: To inspect the potential diagnostic role of in vivo 1H MRS lipid methylene CH2 to methyl CH3 signal ratio in differentiation of recurrent brain tumor from radiation injury.

Methods: Two patients--one with documented recurrence and the other without recurrence--were monitored by means of 1H MRS before and during two years after radiation therapy. The comparative group consisted of 20 patients with glial tumor recurrence diagnosed 2 years after the radiotherapy.