Multivariate regression analysis based on various clinical factors has provided useful information to predict tumor clearance probability and patient prognosis. However, this type of approache alone has an apparent limitation in providing information required for changing the treatment strategy, because the biological roles of clinical factors involved in tumor radioresistance are complicated and unknown. In this review, importance of clinical data on the precise tumor volume and the dose required for the local control has been emphasized, because these data are directly related to both the in situ cellular radioresistance and the size of target cell population. Using a biological model tumor system with these clinical data, it was shown that human tumor radioresistance is likely determined by a small number of target cells with in situ radioresistance in tumor tissue. Thus, the problems shown below targeted to this cell population need to be further investigated. Namely: (1) Mechanism of radioresistance acquired in a hypoxic environment.(2) Topographical distribution of target cell population in a tumor tissue.(3) Research and development for new laboratory tests to diagnose molecular characteristics of the target cell population.

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Purpose: To evaluate the preliminary results of accelerated hyperfractionated radiotherapy with involved-field omitted elective nodal irradiation (ENI) for inoperable advanced non-small cell lung cancer.
Materials and Methods: Ten patients with inoperable advanced non-small cell lung cancer were treated with accelerated hyperfractionated radiotherapy with involved-field omitted ENI between November 2001 and November 2003. The clinical stage for one patient was stage IIB, 3 patients were stage IIIA, and 6 patients was stage IIIB. Chemotherapy was performed 8 patients (sequential: 1 patient, concurrent: 7 patients). The involved-field consisted of the primary tumor and nodes with a short-axis diameter more than 1 cm on CT scans. Total dose was 72 Gy and 74.6 Gy in 2 patients treated with radiation therapy alone, 75 Gy in 1 patient treated with sequential chemotherapy, 66 Gy in 6 patients and 72 Gy in 1 patient treated with concurrent chemotherapy. Follow up periods were between 2 and 25 months (median: 14 months).
Results: Local recurrences developed in 3 patients with the two year local control rate at 49.4%. Out-field regional recurrence developed in one patient, the two years regional control rate was 88.9%. Two years cause specific and overall survival rate was 47.4%. Adverse events were evaluated NTC-CTC ver.3.0. Three patients in 8 patients treated with chemotherapy developed grade 3 neutropenia. Two and 1 patient developed grade 2 and 3 pneumonitis, respectively. Nobody developed more than grade 2 esophagitis.
Conclusions: Accelerated hyperfractionated radiotherapy with involved-field omitted ENI was feasible with limited toxicity.

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Purpose: To evaluate the effectiveness and safety of the combination of external irradiation and interstitial brachytherapy twice per day for prostate cancer.
Materials and Methods: The cases were 42 patients with prostate cancer (4 cases in Stage A, 14 in Stage B, 20 in Stage C and 4 in Stage D) who underwent external irradiation of 50 Gy to the prostate gland including 30 Gy to the pelvis and interstitial brachytherapy of 5.5Gy×2/day in 4 cases, 7.0Gy×2/day in 2 cases and 7.5 Gy×2/day in 36 cases. The average age was 77.5 (range 61 to 89) years old.
Results: Prostate specific antigen (PSA) values after the combinated radiation therapy dropped in each case. Three cases with PSA failure were noted during the average observation term of 12 months. No cases with stage A, B or less than Gleason score 6 were associated with PSA failure. Biochemically no evidence of disease (bNED) survival curve showed significant PSA failure in the cases with PSA values of ≥30ng/ml than in those with PSA values of <30ng/ml. Transient rectal bleeding (2.3%), diarrhea (7%) and perianal pain (4.7%) as adverse effects of radiation treatment were noted.
Conclusion: Initial results of external irradiation and interstitial brachytherapy twice a day are promising especially for aged cases with early prostate cancer. However, longer-term observation is needed to evaluate the real effectiveness and the adverse effect of this combinated radiation therapy.

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We took a routine conservative approach for hypopharyngeal carcinoma. This retrospective study analyzes the outcome of treatment with this policy. Between 1993 and 2002, 36 patients with hypopharyngeal carcinoma received radiotherapy with or without chemotherapy at our institution. Doses ranged from 60 Gy to 72 Gy given to the involved fields. Fourteen patients received CDDP and 5FU, either inductive or concurrent with radiotherapy. The overall five-year survival was 38% and the two-year local control rate was 69%. The local control rate was dependent on the size of primary tumor. Two-year local control rates were 60% with radiotherapy alone and 88% with chemoradiotherapy. Neck dissections combined with radiotherapy were all successful for 12 patients with N1-2. In 14 patients with NO, 3 patients were salvaged successfully after nodal recurrence. Ultimate conservation rate of laryngo-pharynx was 67%. This non-surgical therapy provided survival comparable with that achieved with the standard approach of surgery and postoperative radiotherapy.

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Purpose: Evaluation of our treatment outcome of nasopharynx cancer for a neoadjuvant chemotherapy followed by radiation was performed. In addition, we reviewed whether presence of findings of extracapsular spread (ECS) in cervical node metastasis in MRI influenced treatment outcomes.
treated with radical chemoradiation between 1991 and 2002 at Kurume University Hospital. They were UICC 1997 stage II-IV (stage II: 5 patients, stage III: 10 patients, stage IV: 13 patients). Patients ranged in age from 16-71 years, with a median of 56 years, and included 22 men and 6 women. We administered 1-3 courses of systemic chemotherapy before radiotherapy. Follow-up period was at least 6 months from the beginning of radiation therapy. We performed MRI before treatment for all cases. Metastatic lymphnode, that showed the presence of a perinodal high signal intensity area on STIR sequence or presence of a diameter greater than 3 centimeters in the longest axis, were defined as ECS.
greater than 3 centimeters in the longest axis, were defined as ECS. Results: Four patients developed distant metastasis after initial therapy, and at 3-years the distant failure free rate was 75%. The three-year overall survial rate and failure free rate were 59% and 55%, respectively. In MRI, metastatic cervical lymphnodes were deteced 21 (75%) among the 28 patients, and the findings of ECS were noted for 11 cases (52%) of these 21 patients. None of the patients without the findings of ECS developed distant metastasis. In chisquare analysis, a significant relationship was noted between the findings of ECS and distant metastasis.
Conclusion: The neoadjuvant chemotherapy followed by radiation for nasopharynx cancer did not lead to satisfactory treatment outcomes. It seems that the findings of ECS in MRI might be a important factor to develop distant metastasis.

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In April 2001, an over dose irradiation accident happened in Tokyo. In August 2002, we investigated the wedge factor which became the cause of the over dose irradiation accident. The investigation centered around the wedge factor and the measuring method used TPR 20 and 10 beams. The monitored dose units were calculated and then reconfirmed. The investigation was conducted to 78 institutions in the Kinki region. The answers were received from 61 institutions, and covered 78 equipments units, 40 types (while 6 were unidentified) and 135 beams. Measured acceleration energy varied within 1.0 MV at nominal energy of 4 MV, and varied within 2.8 MV at nominal energy of 10 MV. With regard to the MU calculation, the institutions over 60% of use RTP. The over half of institutions responses reconfirmed calculation results by the measurement. However, several institutions (13%) make no reconfirmation. Fifty-seven percent of institutions measured the wedge factor by calibration depth. Ninety-seven percent of institutions measure the wedge factor by 10×10cm in a radiation field. All wedge factors were classified in tables according to manufacturersor energies

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A nationwide survey was performed to investigate quality assurance (QA) for photon external radiotherapy. It was carried out by mailing questionnaires to 737 radiotherapy facilities. Six hundred and twenty eight questionnaires were returned, and 603 answers (including 38 answers from 60Co facilities) were available for analysis. At 565 X-ray treatment facilities, only 68 facilities (12%) treated more than 40 patients per day. The 356 facilities (63%) treated less than 20 patients per day. In this survey we examined following itemes: 1) number of radiation oncologists and radiotherapy technologists (RTT) each facility, 2) individuals responsible for QA, 3) ratio of conducting periodic check for basic QA items, and 4) Ratio of verifying monitor unit (MU) calculation. This survey shows that QA is not satisfactory at most of Japanese radiotherapy facilities.

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Abstract: Purpose: Ir-192 thin wires were used in our hospital since December l997 for low dose rate brachvtherapy for prostatic carcinoma. Since February 2000, we used the therapeutic planning system which created a pattem of dose distribution from a transrectal echogram, however, there were difnculties associated with this treatment which we tried to improve. However. a technical problem with the Ir-192 low dose rate brachytherapy became obvious. Improvements to the method have been tried since October 2001, and are reported here.
Method: We performed brachytherapy for localized prostatic carcinoma on 105 patients ffom February 2000 to February 2003. We defined the period from February 2000 to September 2001 as the early phase (47 cases). The period from October 2001 to February 2003 was defined as the late phase in which technical improvements were introduced (58 cases). We compared the late phase with the early phase. The early phase treatment procedure is as fbllows. We did centesis with a plastic needle for the prostate gland using transrectal ultrasound as aguide through the aperture of a template by a transperineal approach. The position of the paracentesis needle was checked by CT and also obtained a pattern of dose disnibution in 2 dimensions from the maximal profile of the prostate gland. This was analysed and dose rate calculated and radiation source halt time. We set the clinical target volume around the circumferential part of the prostate gland. We inserted radiation source in apallium needle and then fixed them in situ. However, the next points were modified. 1) We changed the posmre of apatient into extended lithotomy. 2) We nvested the position of thetransrectal ultrasound probe in a part of infraversion/dorsum. 3) A metal marker was inserted into the apex of the prostate gland and was maintained. 4) We contrasted the urethra by means of transrectal ultrasound. 5) The calculatedose distribution ffom the transrectal ultrasound fbr therapeutic planning could be obtained in 3 dimensions. The dose volume histogram was calculated in relation to the prostate, urethra and rectum from which we decided the dose rate. Each technical improvement was evaluate.
Result: 1) The loading of the needle, which avoided the pubic arch by taking the extended lithotomy was enabled. 2) Visualization enabled a good amount of the border area of the prostate gland by positioning of the transrectal ultrasound probe moving towards the dorsum. 3) We inserted a metal marker at the gland apex part in order to aim the radiation source displacement and maintain it. 4) It became easy to identify the urethra by contrasting it. 5) We devised a configuration of paracentesis needle. It became technically clear that the dosage to the urethra and the rectum could be decreased by these improvements. Conclusion: We evaluated the problem of brachytherapy fbr localized prostatic carcinoma with a low dose rate Ir-192 thin wire. We introduced technical improvements to improve treatment. This has provided a refbrence point for further technical improvements for brachytherapy for prostatic carcinoma.

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