Search

A calibration service using a medical accelerator has been launched to calibrate a radiotherapy dosimeter in terms of an absorbed dose to water. The radiotherapy dosimeter calibrated by the calibration service can measure the absorbed dose to water without a beam quality conversion factor. In this paper, an overview of the calibration service for a high-energy photon beam and a high-energy electron beam was described, as well as methods of absorbed dose measurement and cross-calibration using the calibrated radiotherapy dosimeter. And the development status of a dose standard for a particle beam was reported.

We have developed an Electron-Tracking Compton Camera (ETCC) for medical imaging due to its wide energy dynamic range (200-1,500keV) and wide field of view (FOV, 3 str). This camera has a potential of developing the new reagents. We have carried out several imaging reagent studies as examples; (1) 18F-FDG and 131I-MIBG simultaneous imaging for double clinical tracer imaging, (2) imaging of some minerals (Mn-54, Zn-65, Fe-59) in mouse and plants. In addition, ETCC has a potential of real-time monitoring of the Bragg peak location by imaging prompt gamma rays for the beam therapy. We carried out the water phantom experiment using 140MeV proton beam, and obtained the images of both 511 keV and high energy gamma rays (800-2,000keV). Here better correlation of the latter image to the Bragg peak has been observed. Another potential of ETCC is to reconstruct the 3D image using only one-head camera without rotations of both the target and camera. Good 3D images of the thyroid grant phantom and the mouse with tumor were observed. In order to advance those features to the practical use, we are improving the all components and then construct the multi-head ETCC system.

Radiation therapy uses ionizing radiation to kill cancer cells and shrink tumors, with consideration to minimize harmful damages to health tissues. About 30% of all people with cancer are treated with radiation therapy, either alone or in combination with chemotherapy. Radiation therapy may be internal or external. In brachytheraphy as the internal radiation therapy the radioisotope is implanted into or near the tumor by tubes as the container. And it is often used for patients with the tongue cancer. External radiation, the type most often used, comes from a machine outside the body. It is usually used for shrinking tumors with bony invasions such as gingival cancer and improving the pain in patients with bony metastasis. For the primary bone tumor the radiation therapy is not always used because the radiosensitivity of the almost primary bone tumor is low.

We computed the differential dose albedo (alpha(D)) for high-energy X-rays on a concrete slab when the incident angle, reflection angle, and azimuth angle were changed, by means of Monte Carlo simulation. We found that alpha(D) changed with incident, reflection, and azimuth angles to the concrete slab. On the whole, the larger the incident angle, the larger alpha(D) tended to become. If the incident angle and reflection angle were the same, the larger the azimuth angle, the smaller alpha(D) tended to become. When the incident, reflection, and azimuth angles were the same, the smaller the X-ray energy was, the larger alpha(D) became, in the order of 10 MV, 6 MV, and 4 MV X-rays.

The collimator scatter factor (S(c)(MLC)) at MLC irregular fields for high-energy X-ray irradiation is generally assumed to be equal to the jaw collimator scatter factor (S(c)(jaw)) of the square field equivalent to the rectangular field produced using pairs of jaw collimators. However, this assumption becomes strained as the ratio of the MLC equivalent square field side to the jaw collimator equivalent square field side decreases. In this study, for 4 MV and 10 MV X-rays, the collimator scatter factor (S(c)(MLC)) for an MLC irregular field could be evaluated with a high degree of accuracy using the MLC irregular correction (F(MIC)) factor or the jaw collimator correction (F(JCC)) factor.

This review article aims to overview modern prostate brachytherapy in Japan. Permanent transperineal prostate brachytherapy with I-125 started in September, 2003 in Japan. Brachytherapy has several advantages: the dose is adapted precisely to the tumor shape and size, and the long-lived isotope gives a higher tumor dose with less damage to normal tissue; less-time consuming for patients and staff: long-term results comparable to surgery or external beam series in the USA; and quality of life after brachytherapy also appealing. These advantages have brought about increasing use in Japan as well. Patients with a high probability of organ-confined disease and a low-risk group are appropriately treated with brachytherapy. Brachytherapy candidates with a significant risk of extraprostatic extension should be treated with supplemental external beam radiation therapy. High-dose-rate (HDR) brachytherapy with Ir-192 has preceded seed implants in Japan. HDR has some theoretical advantages. Long-term results of brachytherapy in the USA are comparable with surgery or external beam irradiation so far. We should develop more sophisticated brachytherapy techniques in Japan.

Bone metastases are one of the most common conditions requiring radiation therapy today. Its main aim is relief of bone pain, prevention of pathological bone fractures as well as its healing, with anticipated effect upon improving mobility, function, and quality of life. For localized bone pain, external beam radiation therapy (EBRT) will be successful in reducing pain in some 80% of patients. However, optimal fraction dose and total doses of EBRT required for pain relief have been unknown. According to the recent reports, carbon ion radiotherapy seems to be a safe and effective modality in the management of metastatic bone tumor not eligible for conventional EBRT. For scattered painful metastases, the systemic administration of radioisotopes is thought to be effective.

The Japan Society of Medical Physics (JSMP) has published a new dosimetry protocol "JSMP-01" for the calibration of radiotherapy beams. This protocol provides a new definition of the calibration point (depth) in order to obtain the absorbed dose at a reference point (D(r)) by the calculation in high energy electron beams. This study evaluated the difference in the absorbed dose at the depth dose maximum (D(dmax)) and D(r) calculated from the absorbed dose at the calibration point. Further, the difference in the absorbed dose (D(dmax)) at "measured maximum depth (d(max))" was evaluated using "temporary maximum depth (d(max*))." In the experiment at a depth interval of 0.1 g cm(-2), no difference was observed between D(dmax) and D(r). However, in the experiment at a depth interval of 0.3 g cm(-2) the differences between D(dmax) and D(r) increased to 6.4% and 5.2% at 4 MeV and 6 MeV, respectively. Subsequently, at all energy levels the difference between D(dmax) and D(r) of all energy was more than 3% at a depth interval of 0.4 g cm(-2). The differences between D(dmax) and D(dmax*) were 2.68% and 4.50% at 6 MeV and 9 MeV, respectively, for this depth interval.

The Japan Society of Medical Physics (JSMP) Task Group published Standard dosimetry of absorbed dose in external beam radiotherapy (Standard dosimetry 01) as a new high-energy photon and electron dosimetry protocol in 2002. In this study, we present Standard dosimetry 01 as the JSMP-01 protocol for the convenience of users. This protocol is based on using an ion chamber having a (60)Co absorbed dose to water calibration coefficient, N(D,w), which is calculated from a (60)Co exposure calibration coefficient, N(c). We present dose comparisons between a reference chamber and various plane-parallel chambers. The absorbed dose to water was compared at the calibration depth of 5 cm for a (60)Co beam and d(c) = 0.6R(50) - 0.1 (cm) for electron beams according to JSMP-01. The absorbed dose to water calibration coefficients, [N(D,w)](Co) and [N(D,w)](18E), for the plane-parallel chambers were also determined by (60)Co and electron beam cross-calibrations using a reference chamber. The dose for the plane-parallel chambers derived from [N(D,w)](Co) and [N(D,w)](18E) was compared to that for the reference chamber using electron beams. The JARP chamber in the Kyushu Regional Center which meets third-order standards in Japan was used as the reference chamber. The doses for the plane-parallel chambers determined according to JSMP-01 agreed with that for the JARP chamber within 1% and 2% for (60)Co and electron beams, respectively. For electron beams, the doses for the plane-parallel chambers calculated from [N(D,w)](Co) and [N(D,w)](18E) were within 1.5% and 1.0% compared to those for the JARP chamber, respectively, except for the Exradin A10 chamber.

The Japan Society of Medical Physics (JSMP) Task Group published Standard dosimetry of absorbed dose in external beam radiotherapy (Standard dosimetry 01) as a new high-energy photon and electron dosimetry protocol in 2002. In this study, we present Standard dosimetry 01 as the JSMP-01 protocol for the convenience of users. This protocol is based on using an ion chamber having a (60)Co absorbed dose to water calibration coefficient, N(D,w), which is calculated from a (60)Co exposure calibration coefficient, N(c). We present dose comparisons between a reference chamber and various Farmer-type cylindrical chambers with different wall materials. The absorbed dose to water was compared at the calibration depths of 5 cm for a (60)Co beam, 10 cm for photons, and d(c) = 0.6 R(50) - 0.1 (cm) for electrons according to JSMP-01. The JARP chamber in the Kyushu Regional Center which meets third-order standards in Japan was used as the reference chamber. The absorbed dose to water for the Farmer-type chambers determined according to JSMP-01 agreed with that for the JARP chamber within 1% for photon and electron beams. The doses obtained by JSMP-01 and the Japan Association of Radiological Physics protocol (JARP-86) were also compared for photon and electron beams. For the Farmer-type chambers with photon beams, JSMP-01 results were up to 1.5% higher than JARP-86 results. For electron beams JSMP-01 results were higher than JARP-86 results by 1.3-2.8%.

Calculation of in-air or in-water dose for 4 MV X-ray irregular fields could be accurately performed using the collimator scatter factor (S(c)) and phantom scatter factor (S(p)) concepts. It has been revealed that the equivalent square field for a multi-leaf collimator (MLC) irregular field can be evaluated accurately by using the S(p)-Clarkson or S(c)-Clarkson integration method; however, the S(c)-Clarkson integration method is more straightforward because the S(c) factor expresses the in-air X-ray output factor. It has been found that when the MLC field is relatively much smaller than the main collimator field, the Sc factor can be accurately evaluated by introducing the small segment correction (SSC) factor (except for the case in which the MLC field is less than 1 x 1 cm(2)). It has also been found that both the S(p) factor and the tissue-phantom ratio (TPR) can be precisely evaluated by introducing the F(MLC) factor in cases in which the ratio of the MLC equivalent square field side to the main collimator equivalent square field side is less than about 0.7.

The output factor of high-energy X-ray machines varies with collimation. According to Khan's theory, collimator and phantom scatter factors contribute to total scatter factor. For precise X-ray irradiation, the two factors need to be taken into consideration. To obtain proper factors, we made two original polystyrene cylindrical mini-phantoms. These phantoms are both 4 cm in diameter and have a pinpoint ion chamber placed at a depth of 5 cm and 10 cm, respectively. Using a 6 MV X-ray machine, collimator scatter factors were calculated for various field arrangements (i.e., field sizes ranging from 4 cm x 4 cm to 40 cm x 40 cm at isocenter). To determine if calculated values were appropriate, we measured point doses of 20 X-ray irradiation patterns using a Farmer-type ion chamber with a water equivalent phantom at depths of 5 cm and 10 cm, respectively. Two hundred MUs were irradiated to the above-mentioned depths for each field. Based on the measured doses, variations were obtained for four calculation methods. Accounting for 1) secondary collimator (jaw) setting, 2) blocked field (multi-leaf collimator) setting, 3) Khan's theory using a 5 cm mini-phantom, and 4) Khan's theory using a 10 cm mini-phantom. Dose variations in each method of calculation were as follows: 1) +0.3 to +10.2% (mean, +2.0 to +3.2%) , 2) -2.3 to 0.0% (mean, -0.8 to -0.6%), 3) 0.0 to +1.5% (mean, +0.1 to +0.3%), 4) 0.0 to +1.4% (mean, -0.1 to +0.1%).

Effects of radiation therapy for lymph node metastases from gastric cancer were retrospectively analyzed. The radiation sites were residual paraaortic lymph node involvement and postoperative recurrent lymph node metastases in 10 patients. The size of lymph node swelling was decreased in 6 (60%) patients after radiation therapy using liniac. Complaints due to lymph node metastases such as pain and edema of extremities were voiced by 7 patients. These complaints were eventually relieved or disappeared in all 7 patients. There were no severe adverse effects during radiation therapy, and 7 patients (70%) could shift to home care. One-year and 3-year survival rates were 20 and 10%, respectively. Radiation therapy for lymph node metastases from gastric cancer was chiefly effective in relieving complaints. Although it is unclear whether radiation therapy can improve the survival rate, these results suggest that radiation therapy could be one of the most useful locoregional therapies for paraaortic lymph node involvement and recurrent lymph node metastases from gastric cancer.

Purpose: To present the initial experience with proton beam therapy at the new Proton Medical Research Center (PMRC) of the University of Tsukuba., Materials and Methods: The new facility has a synchrotron with maximum energy of 250MeV and two rotational gantries. We treated 105 patients with 120 lesions with proton beams in the first year, beginning in September 2001. The most common lesion treated was primary liver cancer (40 lesions) followed by lung cancer, head and neck cancers, and prostate cancer. Concurrent X-ray radiotherapy was given for 38 of the 120 lesions., Results: The median follow-up period was 11 months (range, 1-19 months). Of the 105 patients, 97% had Grade 0-2 RTOG/EORTC acute morbidities, while the remaining 3% had Grade 3. Tumor response after irradiation was CR for 35% of the lesions, PR for 25%, SD for 22%, PD for 9%, and not evaluated for 9%., Conclusion: The proton beam therapy conducted at the new facility of the University of Tsukuba was safe and effective.

A 72-year-old man with common bile duct cancer was treated by pylorus preserving pancreatoduodenectomy with D3 lymph node dissection and preventive radiotherapy at hepaticojejunostomy. At 4 months after surgery, CT demonstrated multiple liver metastatic tumors. Single drug chemotherapy, UFT 600 mg, was started. After 6 months, the liver metastatic tumor could not be seen by CT. UFT may be a first candidate for chemotherapy for recurrence of bile duct cancer.

The Japan Society of Medical Physics (JSMP) has published a new dosimetry protocol "JSMP-01" (standard dosimetry of absorbed dose in external beam radiotherapy) which conforms to the recommendations of the International Atomic Energy Agency (IAEA TRS-398) and the American Association of Physicists in Medicine (AAPM TG-51) protocols for the calibration of radiotherapy beams. Since the new protocol offers the physical data for the Famer-type ionization chambers of the various wall materials, the user can measure the absorbed dose at reference point (D(r)) using most of the commercially available Famer-type ionization chambers. In this paper, the six Famer-type ionization chambers of the various wall materials are examined for photon beam by two ways. To verify the JSMP-01 protocol as the first way, D(r) was cross-measured based on the JSMP-01 protocol using a Farmer-type ionization chamber of the acrylic wall material which is called "JARP-chamber" and the Farmer-type ionization chambers of the various wall materials, and compared. To compare the basic data in previous and new protocols as the second way, D(r) was measured based on the previous protocol (JSMP-86) and the JSMP-01 protocol using the Farmer-type ionization chambers of the various wall materials. Dose calculation was made using common exposure calibration factor for (60)Co gamma-rays (Nc) for each of the Farmer-type ionization chambers. Measurement was made with each ionization chamber for 6 and 10 MV photon beams in two facilities. D(r) were found to agree to that of JARP-chamber within about +/- 1% despite significant differences of ratio of calibration factor (k(D,X)) and beam quality conversion factor (k(Q)) for photon beams. The ratios JSMP-01/JSMP-86 of the reference dose were found to lie on between 0.999 and 1.004 for 6 MV and on between 0.999 and 1.005 for 10 MV depending upon the Farmer-type ionization chambers used. The largest discrepancies between the previous and new protocols arise from the use of different data of k(D,x) x k(Q) and C(lambda) for the absorbed dose conversion factors of each ionization chamber.

After greater than 60 gray (Gy) irradiation, we performed the pulmonary resection in the 18 primary lung cancer cases. The mean irradiation dose to the tumor was 68.2 (range 60-101) Gy, and the mean irradiation dose to the bronchial stump was 47.1 (range 0-82) Gy. Median time from end of irradiation to surgical resection was 136 (range 20-894) days. One partial resection, 9 single lobectomies, 3 double lobectomies, and 5 pneumonectomies were done. Mainly, we closed the bronchial stump by the automatic stapling device and additional hand suturing. The bronchial stump was covered in the 12 cases by the owner stalk thymus, the intercostals muscular flap, the omentum flap, and et al. The major postoperative complications due to preoperative irradiation were not seen. Bronchopleural fistulas did not occur. Pathologically, the wall of the submucosal capillary vessels were getting thick in the patients operated more than 3 months later after irradiation. In such cases with the decrease of the blood flow, the bronchial stump should be covered. The pulmonary resection after the high dose irradiation was considered to be tolerable.

Clinical trials of carbon beam radiotherapy for stage I non-small cell lung cancer (NSCLL), and their results, are briefly described. The local control rate, cause-specific and overall survival rates of 146 patients with clinical stage I NSCLC were 82.0%, 59.0% and 59.0%, respectively. Radiation pneumonia was not serious and infrequent (2.1%). In the phase II clinical study, the local control rate of 50 patients was 100% without radiation pneumonia, resulting in a 74.0% overall survival rate. Carbon beam therapy could be an alternative to surgery, especially for lung cancer patients of advanced age and/or with complications. For locally advanced lung cancer treated with carbon beams, excellent local control as in stage I NSCLC has been demonstrated, providing hopeful prospects for the treatment of lung cancer.

The goal of radiation therapy for non-small cell lung cancer (NSCLC) is to improve the survival rate of patients without increasing treatment-related toxicity and to improve patients' quality of life. Several prospective randomized trials have demonstrated a survival advantage in combined modality treatment over radiotherapy or chemotherapy alone when a cisplatin-based chemotherapy regimen is utilized in the treatment plan. Combined modality treatment of cisplatin-based chemotherapy and radiotherapy is standard treatment for selected patients such as those with better performance status with locally or regionally advanced lung cancer including T3-T4 or N2-N3. Determining the contribution of new agents in combined modality treatment will require carefully designed and conducted clinical trials. High-dose involved field radiation therapy using 3D-conformal radiation therapy potentially enables the use of higher doses than standard radiation therapy, because less normal tissue is irradiated, and may improve local control and survival. The combination of radiotherapy with chemotherapy and dose escalation using 3D-conformal radiation therapy is also a possibility in unresectable NSCLC. In surgery cases, the results of several Phase III trials of cisplatin-based preoperative chemotherapy have suggested survival improvement. But the concept needs to be tested in a larger Phase III trial.

We performed preoperative combined therapy using nedaplatin (CDGP) and radiation in 12 patients with squamous cell carcinoma originating from the oral cavity and maxillary sinus, and examined for any adverse events that may have occurred during this therapeutic regimen. Regarding the irradiation, external irradiation utilizing a 6 MV linac (linear accelerator) at a dose of 2.0 Gy/day was performed 5 times a week, with the target total radiation dose set at 40 Gy. In addition, CDGP was intravenously administered 30 minutes before irradiation at a dose of 5 mg/m2/day. Mucositis was observed in all 12 subjects, however, the severity was observed to be grade 1-2 with no major differences in comparison to the patients given standard radiation monotherapy. Two subjects developed grade 3 leucopenia and were thus given granulocyte colony stimulating factor (G-CSF). In addition, grade 2 and grade 3 thrombocytopenia were both observed in one subject each. The subject with grade 3 thrombocytopenia required a platelet transfusion during surgery. No marked changes in serum creatinine levels were noted. These findings are therefore considered to provide evidence supporting the safety of this combination therapy.

Pancreatic cancer is considered to be one of the malignancies most resistant to therapy. It is characterized by early local invasion and distant spread. Therefore, resection with curative intent is limited to a very small proportion of patients. Even in these selected patients, long-term survival remains very poor because of liver and local recurrence. Therefore, control of occult liver metastasis and local residual tumor with perioperative radiotherapy and chemotherapy may provide some palliative benefits, and should have some impact on overall survival. However, none of the studies to date are considered definitive. Japanese pancreatic surgeons have developed a number of adjuvant therapies which theoretically could be good enough to prolong long term survival, however, they have not been tested in randomized controlled trials. Planning co-operative studies on this important issue in pancreatic cancer therapy is urgently needed.

To evaluate the therapeutic effect of IORT for unresectable locally advanced pancreatic cancer, 11 patients treated with IORT and 15 patients treated with palliative therapy only were retrospectively examined. The mean age of the IORT group was 61.9 years, 5 cases were classified into surgical stage IVa, and 6 into stage IVb. The mean age of the palliative therapy group was 69.1 years; 5 cases were classified into surgical stage IVa and 10 into stage IVb. The tumor size was measured in 6 cases in the IORT group, before and after IORT. The tumor was enlarged in 1 case, not changed in 4 cases, and reduced in 1 case. The serum CA19-9 level was measured in 8 cases of the IORT group. Serum CA19-9 was increased in 3 cases, not changed in 4 cases, and decreased in 1 case after IORT. ECOG pain scores were obtained in 9 patients who had complained of pain before IORT, and the score decreased in 7 cases. The median survival was 7.6 months in the IORT group and 3.0 months in the palliative therapy group. IORT may improve patients' QOL by decreasing their pain. However, further studies are necessary to confirm the efficacy of IORT for survival of locally unresectable pancreatic cancer patients, because the patient profile in this study was different in the two groups.

Purpose: To determine the prognostic factors influencing the outcome of bladder cancer patients treated with definitive radiotherapy following transurethral tumor resection (TURBT)., Materials and Methods: From March 1977 through August 1991, 83 patients with muscle-invasive bladder cancer were treated with TURBT (as thoroughly as possible) and definitive radiotherapy (median total dose: 64 Gy, median fractional dose: 2 Gy). Cystectomy was performed when possible for the residual or recurrent invasive cancer following radiotherapy. The median follow-up period was 76 months., Results: The overall survival (OS) and bladder-preserving survival (BPS) rates at 5 years were 38% and 28%, respectively. Univariate analysis indicated that depth of invasion (T2 vs. T3), tumor diameter (< 3 cm vs. > or = 3 cm), and visible (R1) or not visible (R0) residual tumor after TURBT influenced both OS and BPS. In multivariate analysis, absence of visible residual tumor after TURBT was the only significant prognostic factor related to OS (p < 0.001) and BPS (p = 0.002). Five-year OS and BPS were 54% and 43% in T2-3R0 and 14% and 7% in T2-3R1, respectively., Conclusions: Absence of visible residual tumor after TURBT was significantly associated with better overall survival and bladder-preserving survival for muscle-invasive bladder cancer patients treated with definitive radiotherapy following TURBT.

The author examined the natural history of intracranial meningioma after radiotherapy using CT or MR imaging. Twenty patients with intracranial meningioma received radiotherapy from a high-energy linear accelerator (4-10 MV X rays) from 1980 to 1996. The total doses were 50 Gy to the tumor bed in single doses of 2 Gy in 5 weekly fractions. Meningiomas in 10 of 20 patients were reduced within 1 to 38 months after radiotherapy, the average being 11 months. The tumors were controlled for a median of 60 months after radiotherapy (range 19-126 months). Four other patients have shown no change in tumor size after radiotherapy. The tumors were controlled for a median of 70 months after radiotherapy (range 37-127 months). The other six patients have shown tumor growth within 3 to 25 months after radiotherapy, after which the tumors stopped growing for a median of 71 months (range 2-181 months). Neither tumor size nor histological type was related to response. The growth of tumors was controlled by radiotherapy for a median duration of 43 months in the meningothelial type, 52 months in the fibroblastic type, and 61 months in the transitional type. The median duration for all benign tumors was 52 months. A moderate correlation was noted between tumor response and functional outcome after radiotherapy in 9 patients with neurological deficits. The natural histories of intracranial meningiomas after radiotherapy were grouped into three categories. Some tumors showed no change in size over a long period. This was a characteristic response after radiotherapy that differed from that of other brain tumors. The results of this study provide important information for the follow-up of intracranial meningiomas after radiotherapy.

The radiotherapeutic results of 55 patients with carcinoma of the buccal mucosa were analyzed to determine the prognostic factors and appropriate treatment modality. They were classified into 5 groups according to treatment modality: group A (preoperative radiotherapy followed by surgery), group B (interstitial implant), group C (electron therapy), group D (mainly external radiotherapy) and group E (external radiotherapy followed by mold therapy with remote afterloading system). The overall 5-year survival rates for groups A, B, C, D, E and the entire group were 50%, 61%, 67%, 29%, 25% and 48%, respectively. The cumulative 5-year local control rates for groups A through E were 81%, 94%, 75%, 33% and 25%, respectively. In univariate analysis, T stage (T1-2 vs. T3-4), N stage (N0 vs. N1-3), clinical stage (II vs. III-IV), histologic grade (well differentiated vs. moderately and poorly differentiated) and treatment modality (A-C vs. D-E) were significantly related to overall survival (p < 0.05). Multivariate analysis revealed that treatment modality (groups A-C) and N0 stage were significantly associated with favorable prognosis (p < 0.05). These results suggest that interstitial implants are comparable with surgery for T1 to early T3 lesions, with or without slight invasion to the bucco-alveolar sulci or retromolar areas, that can be treated with a single-plane implant.

Between 1989 and 1996, 35 patients with prostate cancer without metastasis received intraoperative radiotherapy combined with external beam radiation. 10 of 16 stage B patients and all of 19 stage C patients received additional endocrine therapy for the initial treatment. The radiation therapy included 25-30 Gy of intraoperative radiotherapy for prostate and 30 Gy of external beam radiotherapy for small pelvic region. One patient of stage C was dead for cancer and 4 patient were dead for other causes during 15-99 (mean: 41.6) months follow up period. The overall actuarial survival at 5 years by Kaplan-Meier method were 92.3% for stage B and 87.2% for stage C. Although cystitis, proctitis and anal bleeding were observed as the adverse effects of radiotherapy, both acute and chronic symptoms were not critical. In conclusion, intraoperative radiotherapy combined with external beam radiotherapy was revealed as an effective treatment for prostate cancer without metastasis.

The results of intraarterial chemotherapy (IACT) combined with definitive radiation therapy for 23 advanced and bulky carcinomas of uterine cervix are reported. IA-CT with cisplatin 50 mg and doxorubicin 30 mg was administered by one shot method in bilateral internal iliac arteries. The protocol consisted of one to three treatment session every 3 weeks. Nine of eleven patients with clinical stage III achieved a complete local response (82%), and the 3- and 5-year survival in these cases were 72% and 72%, respectively. These results were superior to the response (58%), 3- and 5-year survivals (68%, 58%) obtained in 19 patients treated mainly with radiation therapy alone. The side effect of grade 2 and 3 for the intestine, such as ileus and hemorrhagic colitis, was noted in 3 patients (15%). In addition, 3 of 8 patients with radical surgery and postoperative radiation therapy after IA-CT developed insufficient fracture of pelvic bone. These complications accompanied by IA-CT combined with radiation therapy and/or surgery increased slightly, compared with that by the previous therapy without IA-CT, but were not critical. The results suggest that IA-CT following radiation therapy is effective to improve the prognosis of patients with Stage III cervical cancer.

In the management of patients with localized prostate cancer, both radical prostatectomy and radiotherapy are shown in the U.S. to be equally effective to control a local disease but associate with different types of toxicity. Therefore, both treatments are recommended for patients to choose freely. Recently, mainly in western countries, radiotherapy has achieved technological innovation so as to increase target tumor doses and to decrease the volume and dose of peritumoral normal tissues, by which the treatment outcome is further improved. Major innovative techniques include three-dimensional conformal radiotherapy (3D CRT) and a high dose-rate (HDR) brachytherapy system. Three-D CRT focuses radiation on the tumor through multiple portals minutely tailored to the tumor volume determined by computed tomography, in conjunction with a sophisticated treatment planning system. A HDR brachytherapy system provides high-tech interstitial radiotherapy; a remote afterloading system precludes radiation exposure of hospital workers and a computer-controlled source-scanning system enables optimization of dose distribution. In order to provide a variety of effective treatment options for Japanese patients, radiation oncologists must master these techniques in practice, in cooperation with urologists.

Between 1994 and 1996, 24 patients with esophageal carcinoma were entered in a randomized clinical trial comparing radiotherapy (RT) only (arm A) versus RT and a daily low dose of CDDP (5 mg/m2) (arm B). For arm B group, CDDP was injected within 30 min after irradiation. All patients were irradiated with a total dose of 60 Gy /30fr. at first, and some patients were boosted. An overall response rate of 75.0% (complete response rate of 25.0%) was observed in arm A and 91.7% (complete response rate of 16.7%) in arm B, respectively. The survival rate at 1 year was 23.8% in arm A and 40.0% in arm B. Median survival time was 7 months in arm A and 9 months in arm B. Toxicity was acceptable and no significant difference was noted between arm A and arm B.

A 61-year-old-male with local advanced inoperable cervical esophageal cancer (squamous cell carcinoma, T4N1M0 stage III) was treated by concurrent radiochemotherapy. A dose of 50.6 Gy/46 Fr/36 days and one course each of CDDP-5-FU and nedaplatin-5-FU were delivered safely. Radical surgery could be performed thereafter because of the good tumor response. Pathological CR was obtained in metastatic cervical lymph nodes and almost total necrosis in primary cancer. Concurrent radiochemotherapy produced a significant improvement in this case of advanced cervical esophageal cancer.

Thirteen patients with advanced gastric cancer treated by palliative radiotherapy were retrospectively analyzed. The radiation sites were abdominal cavities in 8 cases, superficial masses in 5 and lung metastasis in one. The purposes were to diminish mass size in 5 cases, to relieve pain in 3 and to reduce stenosis in 6. The total doses were more than 40 Gy in 10 patients. In 2 cases, the intracavitary irradiation was performed using 192Ir. In one case, radiation had to be stopped at the dose of 22.5 Gy because of poor general condition. Partial response was obtained in 6 of 12 cases (RP, 50%). The sites of responders were superficial lesions in 4 and hepatic hilar mass in 2, which were given intracavitary as well as external radiation. Pain relief was achieved in all patients suffering from it. One of 3 cases with esophageal stenosis showed marked improvement in swallowing. Two patients showed a decrease in the levels of tumor markers. Five patients had side effects of more than grade 2. Two of them were grade 3, one thrombocytopenia and one diarrhea. The median survival time of all cases was 9 months, and 5 patients could shift to home care. These results suggest that palliative radiotherapy could be one of the most useful locoregional therapies for advanced gastric cancer, in the aspect of improvement of patient's QOL.

The purpose of this study was to evaluate the impact of administering high doses by rotational multi-leaf collimator (MLC) conformal radiation therapy. From 1984 to 1995, thirty-five consecutive cases with glioblastoma multiforme were treated using rotational MLC conformal therapy. There were 23 men and 12 women, with an average age of 45 years (12-73 years). Median Karnofsky performance score was 80(30-100). Median tumor volume was 56 cc (8-800 cc). All patients underwent surgical intervention (only biopsy in one, partial resection in 13, subtotal resection in 18, and gross total resection in three). Radiation dose ranged from 60 to 80 Gy (mean 68.5 Gy) in 21 patients treated before 1991, and was 90 Gy in the 14 patients treated thereafter. Biweekly intravenous chemotherapy was also administered in both arms. The 1-year, 2-year, and 5-year survival rates were 72%, 43%, and 21%, respectively. Residual tumor volume was the only statistically significant factor for survival by multivariable analysis. The five-year survival rate of patients with residual tumors 2 cm or less in diameter was as high as 44%. Local failure was observed in 15 of the 18 patients in the lower dose group, whereas it was observed in only 4 of the 10 patients in the higher dose group. The difference was statistically significant. Rotational conformal therapy in combination with intensive surgical resection showed a favorable outcome. However, increased dose did not lead to higher survival rate.

Twenty-nine patients with intracranial meningiomas were treated with a high-energy linear accelerator (4-10 MV. X rays and electron beams) between 1980 and 1992 at the Hiroshima Prefectural Hiroshima Hospital. We investigated the relationships between tumor size and tumor response, histological type and tumor response, and grade of operation using Simpson's classification and recurrence rate. Meningiomas were greatly reduced between 1 month and 46 months after radiotherapy, the average being 14 months. In the group with a tumor size of less than 5 cm2, 3 patients obtained CR, 5 patients NC and 1 patient PD. Tumor response was 89% in the group with a combination of CR with NC. In the group with a tumor size of 5 to 20 cm2, 2 patients obtained PR, 1 patient NC and 1 patient PD. Tumor response was 75% in the group with a combination of PR with NC. In the group with a tumor size of more than 20 cm2, 3 patients showed NC, 3 patients PD. Tumor response was 50% in the group with NC. In the group with a tumor size of less than 20 cm2, tumor response was 85%. In the group with a tumor size of more than 20 cm2, it was 50%. Though there were no statistically significant differences between the two groups, a tumor size of less than 20 cm2 had a tendency to be more responsive than one of more than 20 cm2. The response of meningioma of the transitional type was worse than that of the meningothelial type and fibroblastic type. Fourteen patients after Simpson grade II or III operation were free of recurrence. The results of this study support the role of radiotherapy for meningioma which is less than 20 cm2, and also for treatment after Simpson grade II or III operation.

Purpose: Radiation therapy is a useful palliative modality for refractory lesions of multiple myeloma. It has been reported that total doses of 10 to 20 Gy are usually adequate to obtain some degree of pain relief. However, there are many patients who need additional doses to obtain sufficient pain relief. In this study, we retrospectively analyzed the records of patients with multiple myeloma irradiated at our department, in an attempt to develop an effective treatment policy for this disease., Materials and Methods: Twenty-nine patients with 53 lesions were treated between 1968 and 1993. Total irradiation doses were 4 to 60 Gy(median 40 Gy) with daily fractions of 2 Gy or less, and 16 to 51 Gy(median 30 Gy) with daily fractions greater than 2 Gy. Evaluated were 59 symptoms, including pain (68%), neurological abnormalities (15%), and masses (28%)., Results: Symptomatic remission was obtained in 33 of 36 (92%) lesions with pain, 6 of 8(75%) with neurological abnormalities, and 13 of 15(87%) mass lesions. Pain was partially relieved at a median TDF of 34, and completely at a median TDF of 66(equivalent to 40-42 Gy with daily fractions of 2 Gy)., Conclusions: Radiation therapy is an effective and palliative treatment method for symptomatic multiple myeloma. However, the treatment seems to require higher radiation doses than those reported to obtain adequate relief of symptoms.

Radioactive strontium chloride (89Sr) was administered for pain relief in 6 patients with bone metastases (4 prostate cancer and 2 breast cancer patients). Out of 6 patients, 2 showed apparent relief of bone pain and improvement of QOL, and 3 showed slight relief of the pain with or without improvement of QOL; that is, 83% was effective. Side effects were seen in 2 patients; transient deterioration of bone pain in one patient and bone marrow suppression in the other patient. The patient who showed bone marrow suppression had rather more lesions of bone metastasis (diffuse metastasis) and least urinary excretion of the radioactivity. Urinary excretion for 2 days varied 5 to 40% of the administered dose and was less in the patients with more metastatic lesions.

Strontium-89 chloride is widely available in the U.S. and Europe for patients afflicted by bone metastasis associated with pain. 89Sr is a pure beta-emitter and it is thought to be difficult to estimate its distribution externally. We tried to image the distribution of 89Sr uptake with bremsstrahlung from beta-minus decay of 89Sr by using Nal scintillation camera. Pronounced 89Sr depositions in the bone metastatic sites were imaged in the energy windows from 50 keV to 150 keV bremsstrahlung. The distribution of these depositions corresponded to 99mTc-HMDP image may be suspected to the effectiveness of this therapy. The identification of 89Sr distribution might be useful in evaluating the bone marrow radiation dose too.

Pulsed brachytherapy is starting to be used for patients with various kinds of carcinoma, in the expectation of fair treatment results without increasing the late radiation-induced damage. We calculated the early and late biologically effective dose (BED) of this modality to predict early and late radiation damage based on the linear-quadratic model (L-Q model). The way to set the values of alpha/beta and mu (factor of repair) in the L-Q model remains controversial. The value of alpha/beta has been fixed at 3Gy for the late effect and 10Gy for the early effect in recent studies. In this study, we applied these alpha/beta values to calculate the BED, however, the effects of its alteration ranged from 0.5Gy through 15Gy on BED were also analysed. We assumed mu = 0.5 (T1/2 = 1-2 hours) in this study, but we also tried to examine the effects of its variation. Our results indicate that pulsed brachytherapy is a safe treatment procedure even if the dose-rate ranges from 1Gy/hr through 100Gy/hr, but the fractionation number should be increased when using a very high dose rate. Pulsed brachytherapy should be applied cautiously for tissues with a small mu value, such as the spinal cord, because an extremely high late BED would be expected in such cases.

From 1983 to 1992, 248 patients with carcinoma of the uterine cervix were treated with intracavitary radiation therapy using the 60Co remotely controlled high dose rate afterloading system apace (RALS). Five-year survival rates were 92,8 +/- 7 % for Stage I, 72.4 +/- 5% for Stage II and 52.1 +/- 4% for Stage III. The relations among the sequelae in surrounding organs, local control rates and the calculated dose in the rectum, sigmoid colon, bladder and small intestine were evaluated using X-ray CT images. The patients were treated with intracavitary radiation of 6 Gy/fraction at point A. A total of 5 fractions were delivered once a week. The dose calculation was performed by, and dose distribution shown on, a system developed in our hospital with a personal computer. The average values of maximum dose at certain points of the walls of the rectum and sigmoid colon were similar to point A dose. The incidence of late sequelae increased significantly in the group receiving a maximum dose to the rectum and sigmoid colon higher than 8 space Gy/fraction. This report describes the program for automatic optimization of dose distribution by modifying the hot spot (higher than 8 space Gy/fraction) and the cold spot (lower than 6 space Gy/ fraction).

In pelvic irradiation, the volume of irradiated small intestine is one of the major factors responsible for both acute and late gastrointestinal complications. In this study, exclusion of the small intestine from the pelvic radiation field was attempted with lower abdominal wall compression and bladder distention in the prone position. The mobility of intrapelvic and several problems associated with this technique were investigated. In our results, the small intestine was effectively moved outside of the whole pelvic radiation field in all but two patients. Treatment interruption of 2 days was observed in only two patients. With the AP/PA opposing field method the abdominal skin dose near the compression pillow was revealed to be higher and the dose at the isocenter was inhomogeneous; thus, a three- or four-field technique is recommended if abdominal wall compression is used.