Head and Neck Neoplasms ; radiotherapy ; Humans

For the QA of IMRT treatment of head and neck cancer by using M3 (BrainLAB Inc. Germany), it is not easy to measure delivery dose exactly because the dose attenuation appears by the couch according to the position of table and gantry. In order to solve this problem, we fabricated head and neck phantom which would be implemented on the couch mount of Brain Lab Inc. We investigated dose attenuation by the couch and found the difference of dose distribution by the couch, in the applying this phantom to the clinic. After measurement, we found that point dose attenuation was 35% at maximum and dose difference was 5.4% for a point dose measurement of actual patient quality assurance plan.
Brain ; Head and Neck Neoplasms ; Head* ; Humans ; Neck* ; Radiotherapy*

The ultimate goal of radiotherapy is to result in complete local control of tumor while sparing the surrounding normal tissues as much as possible. Since the development of CT in 1970s, patient's anatomical normal tissues and the site and extent of infiltration of tumor were identified almost accurately. In addition, the isodose distribution of delivered radiation to target tumor was shown in each cross-section. In the treatment planning of head and neck cancers, CT-reconstruction provided almost 3-dimensinonal inter-relationship between tumor and normal tissues. The utilization of imaging system of the CT scanner made it possible to illustrate in superposition the patient structure image, the radiation beams, and the isodose distributions. Thus it was possible to deliver radiation enough to control the local disease, and to avoid unnecessary administration of radiation to normal tissue such as spinal cord. CT-reconstructed image in axial, sagittal, and coronal planes suggested 3-dimensional radiotherapy treatment planning be possible and practical instead of conventional 2-dimensional planning at coronal plane.
Head and Neck Neoplasms* ; Head* ; Humans ; Neck ; Radiotherapy* ; Spinal Cord

The basic strategy of irradiation is to deliver a dose to the cancer that is high enough to make cancer cells incapable of reproduction, while keeping the doses to the various healthy tissues below tolerable levels. In order to improve local control and survival, as a boost therapy after external radiotherapy, high dose rate transcatheteric irradiation using remote control after loading system (RALSTRON-20B) was used for twelve patients with head and neck cancers. Present results showed complete remission of cancer in 9 out of 112 patients without treatment related complications. Although this procedure is easy to operate, well trained skillful hand in essential for good results. Furthermore out experience suggested that meticulous treatment planning should be developed for better results.
Hand ; Head and Neck Neoplasms* ; Head* ; Humans ; Neck ; Radiotherapy ; Reproduction

Carcinoma, Squamous Cell ; radiotherapy ; Head and Neck Neoplasms ; radiotherapy ; Humans

PURPOSE: To investigate set-up errors, suggest the adequate planning target volume (PTV) margin and image-guided radiotherapy frequency in head and neck (H&N) cancer treated with intensity-modulated radiotherapy (IMRT) assessed by kV cone-beam computed tomography (CBCT). METHODS: We analyzed 360 CBCTs in 60 patients with H&N cancer treated with IMRT. The target delineation was contoured according to ICRU62. PTVs were generated by adding a 3–5 mm margin in all directions to the respective clinical target volumes. The kV CBCT images were obtained at first three days of irradiation and weekly thereafter. The overall mean displacement, range, systematic (∑) and random (σ) errors were calculated. Adequate PTV margins were calculated according to the van Herk formula (2.5∑ + 0.7r). RESULTS: The mean of set-up errors was less than 2 mm in any direction. The overall frequency of set-up displacements greater than 3 mm was 3.9% in medial-lateral (ML) direction, 8% in superior-inferior (SI) direction, and 15.5% in anterior-posterior (AP) direction. The range of translations shifts was 0–9 mm in ML direction, 0–5 mm in SI direction and 0–10 mm in AP direction, respectively. After systematic set-up errors correction, the adequate margin to overcome the problem of set-up errors was found to be less than 3 mm. CONCLUSION: Image-guided kV CBCT was effective for the evaluation of set-up accuracy in H&N cancer. The kV CBCT at first three fractions and followed-by weekly appears adequate for reducing significantly set-up errors in H&N cancer treated with IMRT technique. Finally, 3–5 mm PTV margins appear adequate and safe to overcome the problem of set-up errors.
Cone-Beam Computed Tomography ; Drug Therapy ; Head and Neck Neoplasms ; Head ; Humans ; Neck ; Radiotherapy ; Radiotherapy, Image-Guided ; Radiotherapy, Intensity-Modulated ; Translations

PURPOSE: To confirm the reproducibility of in vivo transmission dosimetry system and the accuracy of the algorithms for the estimation of transmission dose in head and neck radiation therapy patients. MATERIALS AND MEHTODS: From September 5 to 18, 2001, transmission dose measurements were performed when radiotherapy was given to brain or head and neck cancer patients. The data of 35 patients who were treated more than three times and whose central axis of the beam was not blocked were analyzed in this study. To confirm the reproducibility of this system, transmission dose was measured before daily treatment and then repetitively every hour during the treatment time, with a field size of 10x10 cm2 and a delivery of 100 MU. The accuracy of the transmission dose calculation algorithms was confirmed by comparing estimated dose with measured dose. To accurately estimate transmission dose, tissue inhomogeneity correction was done. RESULTS: The measurement variations during a day were within +/-0.5% and the daily variations in the checked period were within +/-1.0%, which were acceptable for system reproducibility. The mean errors between estimated and measured doses were within +/-5.0% in patients treated to the brain, +/-2.5% in head, and +/-5.0% in neck. CONCLUSION: The results of this study confirmed the reproducibility of our system and its usefulness and accuracy for daily treatment. We also found that tissue inhomogeneity correction was necessary for the accurate estimation of transmission dose in patients treated to the head and neck.
Axis, Cervical Vertebra ; Brain ; Brain Neoplasms ; Head and Neck Neoplasms* ; Head* ; Humans ; Neck ; Radiotherapy

Kimura disease is a rare idiopathic chronic inflammatory disorder. It typically presents in the head and neck area, whereas bilateral involvement is unusual. Its diagnosis requires it to be differentiated from other inflammatory diseases and from head and neck tumors. Treatment methods include conservative management, steroid administration, radiotherapy, and surgery; however, no single treatment of choice has been established. Herein, we report an unusual presentation of Kimura disease with bilateral parotid involvement. This case was treated by surgical excision.
Angiolymphoid Hyperplasia with Eosinophilia* ; Diagnosis ; Head ; Head and Neck Neoplasms ; Neck ; Parotid Neoplasms ; Radiotherapy

Kimura disease is a rare idiopathic chronic inflammatory disorder. It typically presents in the head and neck area, whereas bilateral involvement is unusual. Its diagnosis requires it to be differentiated from other inflammatory diseases and from head and neck tumors. Treatment methods include conservative management, steroid administration, radiotherapy, and surgery; however, no single treatment of choice has been established. Herein, we report an unusual presentation of Kimura disease with bilateral parotid involvement. This case was treated by surgical excision.
Angiolymphoid Hyperplasia with Eosinophilia* ; Diagnosis ; Head ; Head and Neck Neoplasms ; Neck ; Parotid Neoplasms ; Radiotherapy

PURPOSE: To improve the local control of patients with nasopharyngeal cancer, we have implemented 3-D conformal radiotherapy and forward intensity modulated radiation therapy (IMRT) to used of compensating filters. Three dimension conformal radiotherapy with intensity modulation is a new modality for cancer treatments. We designed 3-D treatment planning with 3-D RTP (radiation treatment planning system) and evaluation dose distribution with tumor control probability (TCP) and normal tissue complication probability (NTCP). MATERIALS AND METHODS: We have developed a treatment plan consisting four intensity modulated photon fields that are delivered through the compensating filters and block transmission for critical organs. We get a full size CT imaging including head and neck as 3 mm slices, and delineating PTV (planning target volume) and surrounding critical organs, and reconstructed 3D imaging on the computer windows. In the planning stage, the planner specifies the number of beams and their directions including non-coplanar, and the prescribed doses for the target volume and the permissible dose of normal organs and the overlap regions. We designed compensating filter according to tissue deficit and PTV volume shape also dose weighting for each field to obtain adequate dose distribution, and shielding blocks weighting for transmission. Therapeutic gains were evaluated by numerical equation of tumor control probability and normal tissue complication probability. The TCP and NTCP by DVH (dose volume histogram) were compared with the 3-D conformal radiotherapy and forward intensity modulated conformal radiotherapy by compensator and blocks weighting. Optimization for the weight distribution was performed iteration with initial guess weight or the even weight distribution. The TCP and NTCP by DVH were compared with the 3-D conformal radiotherapy and intensitiy modulated conformal radiotherapy by compensator and blocks weighting. RESULTS: Using a four field IMRT plan, we have customized dose distribution to conform and deliver sufficient dose to the PTV. In addition, in the overlap regions between the PTV and the normal organs (spinal cord, salivary grand, pituitary, optic nerves), the dose is kept within the tolerance of the respective organs. We evaluated to obtain sufficient TCP value and acceptable NTCP using compensating filters. Quality assurance checks show acceptable agreement between the planned and the implemented MLC (multi-leaf collimator). CONCLUSION: IMRT provides a powerful and efficient solution for complex planning problems where the surrounding normal tissues place severe constraints on the prescription dose. The intensity modulated fields can be efficaciously and accurately delivered using compensating filters.
Head ; Humans ; Nasopharyngeal Neoplasms* ; Neck ; Prescriptions ; Radiotherapy, Conformal