BACKGROUND The accuracy of the Elekta Clarity™ three-dimensional ultrasound system (3DUS) was assessed for prostate positioning and compared to seed- and bone-based positioning in kilo-voltage cone-beam computed tomography (CBCT) during a definitive radiotherapy. METHODS The prostate positioning of 6 patients, with fiducial markers implanted into the prostate, was controlled by 3DUS and CBCT....

BACKGROUND Interfraction prostate motion must be compensated by increased safety margins. If filling status of rectum and bladder is constant, motion should be reduced. We attempted to reduce interfraction motion errors by proper patient instruction. METHOD In 38 patients pairs of radio-opaque fiducial markers were implanted prior to definitive radiotherapy. Patients were positioned either ac...

In this study, we compared the motion accuracy of six degrees of freedom (6D) couch for precision radiotherapy with or without weights attached to the couch. Two digital cameras were focused on the iso-center of a linear accelerator. Images of a needle which had been fixed to the 6D couch were obtained using the cameras when the couch moved in translation and rotation around each axis. The thre...

In order to achive best results in radiotherapeutic treatment of tumor tissue, one needs to precisely reconstruct the setup defined in therapy planning before the treatment can start. Inaccuracies in either defining the treatment parameters or transferring positioning markers to the patient’s body, errors in treatment device setup or patient motion during the treatment result in a displacement ...

Changes in the fractionation scheme of radiotherapy course have an impact on results treatment cancer patients. If changes are not taken into account, this leads to under-irradiation tumor cells and a possible occurrence subsequent relapses. There radiobiological models order take account errors radiation dose delivered tumor. They allow predicting control, as well toxicity level normal tissues...

In radiotherapy, abdominal and thoracic sites are candidates for performing motion tracking. With real-time control it is possible to adjust the multileaf collimator (MLC) position to the target position. However, positions are not perfectly matched and position errors arise from system delays and complicated response of the electromechanic MLC system. Although, it is possible to compensate par...

The present study is aimed at determination of accuracy of relocation of Gill-Thomas-Cosman frame during fractionated stereotactic radiotherapy. The study aims to quantitatively determine the magnitudes of error in anteroposterior, mediolateral and craniocaudal directions, and determine the margin between clinical target volume to planning target volume based on systematic and random errors. Da...

background depending on the cause, 40-90% of every deep dermis insult ends up in scar formation. several modalities have been suggested as a treatment but a high rate of recurrence is reported in most of those interventions. high dose radiotherapy has been shown to be effective in reducing the recurrence rate. this study tried to determine the effectiveness of low dose rate radiotherapy followi...

breast cancer is the most common cancer in women after skin cancer. in iran, the presentation age of this cancer is younger than the global average. there are different therapeutic methods for treatment of breast cancer and the choice of treatment depends on the stage of the disease as well as its type and characteristics. therapeutic methods include surgery, radiotherapy, and systemic therapie...

normal skin is composed of epidermis and dermis. skin is susceptible to radiation damage because it is a continuously renewing organ containing rapidly proliferating mature cells. radiation burn is a damage to the skin or other biological tissues caused by exposure to radiofrequency energy or ionizing radiation. acute skin reaction is the most frequently occurring side effect of radiation thera...