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Purpose Emerging data suggest that higher radiation doses in post-mastectomy radiotherapy may be associated with an increased risk of reconstruction complications. This study aimed to validate previous findings regarding the impact of radiation dose on complications among women with breast cancer using a multi-center dataset. Methods Fifteen institutions participated, and women with breast cancer who received radiotherapy after either autologous or prosthetic breast reconstruction were included. The primary endpoint was major post-radiation therapy complications requiring re-operation for explantation, flap failure, or bleeding control. Results In total, 314 patients were included. Radiotherapy was performed using both conventional fractionation and hypofractionation in various schedules. The range of the radiation therapy dose in Equivalent Dose in 2 Gy fractions (EQD2; α/β = 3.5) varied from 43.4 to 71.0 Gy (median dose: 48.6 Gy). Boost radiation therapy was administered to 49 patients. Major post-radiation therapy complications were observed in 24 (7.6%) patients. In multivariate analysis, an increasing EQD2 per Gy (odds ratio [OR]: 1.58, 95% confidence interval [CI]: 1.26–1.98; p, Highlights • Radiation dose is associated with the risk of breast reconstruction complications. • We conducted a retrospective multi-center observational study of 314 women in Korea. • Complication-related risk factors were identified using multivariate analysis. • Use of hypofractionated radiation therapy may improve breast reconstruction outcomes. • A prospective multi-center study is under way to further validate our findings.

Purpose The details of breast reconstruction and radiation therapy (RT) vary between institutions; therefore, we sought to investigate the practice patterns of radiation oncologists who specialize in breast cancer. Materials and methods We identified the practice patterns and inter-hospital variations from a multi-center cohort of women with breast cancer who underwent post-mastectomy RT (PMRT) to the reconstructed breast at 16 institutions between 2015 and 2016. The institutions were requested to contour the target volume and produce RT plans for one representative case with five different clinical scenarios and answer questionnaires which elicited infrastructural information. We assessed the inter-institutional variations in RT in terms of the target, normal organ delineation, and dose-volume histograms. Results Three hundred fourteen patients were included; 99% of them underwent immediate reconstruction. The most irradiated material was tissue expander (36.9%) followed by transverse rectus abdominis musculocutaneous flap (23.9%) and silicone implant (12.1%). In prosthetic-based reconstruction with tissue expander, most patients received PMRT following partial deflation. Conventional fractionation and hypofractionation RT were used in 66.6% and 33.4% patients, respectively (commonest: 40.05 Gy in 15 fractions [17.5%]). Furthermore, 15.6% of the patients received boost RT and 53.5% were treated with bolus. Overall, 15 physicians responded to the questionnaires and six submitted their contours and RT plans. There was a significant variability in target delineations and RT plans between physicians, and between clinical scenarios. Conclusion Adjuvant RT following post-mastectomy reconstruction has become a common practice in Korea. The details vary significantly between institutions, which highlights an urgent need for standard protocol in this clinical setting.

Background: The purpose of this study was to evaluate the usefulness of diffusion-weighted magnetic resonance imaging for monitoring the response to radiation therapy in metastatic bone marrow of the spines. Materials and Methods: Twenty-one patients with metastatic bone marrow of the spines were examined with MRI. Diffusion-weighted and spin-echo MRI were performed in 10 patients before and after radiation therapy with or without systemic chemotherapy, and performed in 11 patients after radiation therapy alone. Follow up spin-echo and diffusion-weighted MRI were obtained at 1 to 6 months after radiation therapy according to patients' condition. The diffusion-weighted imaging sequence was based on reversed fast imaging with steady-state precession (PSIF). Signal intensity changes of the metastatic bone marrows before and after radiation therapy on conventional spin-echo sequence MRI and diffusion-weighted MRI were evaluated. Bone marrow contrast ratios and signal-to-noise ratios before and after radiation therapy of diffusion- weighted MRI were analyzed. Results: All metastatic bone marrow of the spinal bodies were hyperintense to normal bone marrow of the spinal bodies on pretreatment diffusion-weighted MRI and positive bone marrow contrast ratios(p

Purpose: To evaluate the role of MRI in the management of cervical cancer treated by conventional four-field whole pelvic irradiation. Method and material: Between 1993-march and 1994-february, 20 patients(4 Stage I B, 3 Stage II A, 13 Stage II B) with invasive cervical cancer were eligible for evaluation of accuracy of conventionally designed lateral treatment field without MRI determination. Results: 5 out of 20 Patients had inadequate margin without MRI. The position of uterine fundus was more important than cervix in correction of field size and the center of treatment field. Conclusion: This Preliminary data show MRI determination of uterine position prior to radiotherapy planning is essential in the case of four-field whole pelvic irradiation technique.

Total 55 patients with nonsmall cell lung cancer treated with radiation therapy at Department of Therapeutic Radiology, Yeungnam University Hospital, between May-1 1986 and April-30 1993 were retrospectively analyzed by clinical characteristics, failure patterns, follow up duration and survival ratio according to prognostic factors. Obtained results were as follows : 1. Male to female ratio was 17.3 2. Sixth and seventh decades were predominant age group. 3. The patients were 8 in stage I-II, 34 in stage IIIA, 13 in stage IIIb, respectively. 4. Forty five patients out of 55 were squamous cell carcinoma. 5. Primary tumor were originated from upper lobe bronchi predominantly. 6. The size of the primary tumor, lymph node involvement and the degree of differentiation were important in evaluation of prognosis. 7. In conclusion, for patients with poor prognostic factors systemic chemotherapy and multidisciplinary approach were recommended for better treatment outcome and improvement of survival.

Since discovery of X-rays, radiotherapy has evolved into one of the most scientific branches of medicine and has established its role as the primary line or the secondary line of attack, after surgery, in the treatment of malignant cancers. Nowadays its importance is illustrated by the fact that as many as 70 per cent of all pastients with cancer will receive radiation therapy at sometime during their disease process. Biologic effects of X-rays began to be apparant soon after the discovery by Roentgen in 1895. In clinical radiotherapy, the biologic endpoint of most importance is loss of cellular reproductive ability or clonogenicity. One of the commonest ways to assess cell survival is to use an in vitro plating assay. We analyzed radiation effect on colony formation of HaLa.S3(SC) cell line and obtained results are as follows: The plating efficiency is 0.464. The shape of cell survival curve is similar to multi-target plus single hit component model. Estimated values of Do, Dq, and extrapolation number are 150 cGy, 80 cGy and 1.7 respectively. We reported these experimental data with review of literature.

Local excision and axillary dissection followed by radiation therapy to the breast has been shown to achieve equivalent local control and survival as mastectomy in an prospective randomized trials. We analyzed 28 cases of early breast cancer in order to evaluate the therapeutic effects of conservative surgery and definitive radiotherapy in the management of early breast cancer as possible alternative of simple mastectomy, retrospectively. Obtained results were as follows : 1. Treatment related acute side reactions are more prominant in the case of chemoradiotherapy group than radiotherapy alone group. 2. There were no cases of primary, regional or systemic failures on the last follow up examination. 3. Cosmetic results after treatment were satisfactory in 26 cases out of 28 cases on the last follow up examination. 4. There were no demonstrable differences of tumor control and cosmetic results between the treatment groups. Although, these results suggested that definitive radiotherapy after local excision would be a possible and desirable alternative instead of total mastectomy in the management of early breast cancers, analyzed cases were too small and follow up period was too short to evaluate the therapeutic effect of primary radiotherapy after local excision, exactly.

Bone metastases represent an important and frequent clinical problem in patients with advanced cancers. Especially, painful bone metastases are common features in these patients. Radiotherapy is an effective tool for palliative aim of painful metastatic osseous lesions. Various treatment results have been previously reported. The present retrospective study was aimed to evaluate the efficacy of palliative irradiation on pain relief, with the goal of selecting appropriate irradiation dose schedule. Radiotherapy consisted of 5times a week with a various fractional dose between 180 and 400cGy. The response of pain relief and the survival time after completion of radiotherapy are related to total dose and most of the patients have shown a similar response by the end of radiotherapy. The higher dose and the more aggressive multimodality treatment, the better pain control and the longer survival time.

Radiotherapeutically, nasopharyngeal cancer is an important disease in korea. Because of its blind anatomic location, early detection is relatively uncommon. Clinically, most of cases are locally advanced and nodal involvement are common. Recently better understanding of nature of the disease and improvement of radio-therapy technique permit better treatment results, including locoregional control and survival rate, and minimal normal tissue damages comparing with previously published data. We analyzed 31 patients of pathologically proven and previously untreated naso-pharyngeal carcinoma with different treatment techniques, retrospectively. Minimal and maximal follow up period of the survuor is 6 months and 68 months, respectively. Thirteen patients with squamous cell carcinoma are included in this analysis. The median age is 49 years(range from 20 to 64 years). Twenty two patients are stage III. Eleven patients are treated with radiotherapy alone and 20 are treated with comblined modalities treatment. The degree of responses after radiotherapy are categorized by 3-classes, i.e. complete response, partial response. In spite of simioarities of complete response rate and 1-year survival rate between two different treatment techniques, those patients with undifferentiated carcinoma appear to benefit from the adjuvant chemotherapy. In addition, systemic failure is more prominant in radiotherapy alone group than in combined modalities treatment group. These results suggest that adjuvant therapy in the radiotherapeutic management of nasopharyngeal cancers needs additional research according to histologic types and future extensive clinical trials.

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 afterloading system(RALSTRON-20B) was used for twelve patients with head and neck cancers. Present results showed complete remission of cancer in 9 out of 12 patients without treatment related complications. Although this procedure is easy to operate, well trained skillful hand is essential for good results. Furthermore our experience suggested that meticulous treatment planning should be developed for better results.

Scatter-air ratios are used for the purpose of calculating scattered dose in the medium. The computation of the primary and the scattered dose separately is particularly useful in the dosimetry of irregular fields with shielding block in radiation field, dose distribution of scattered radiation using 18MeV Linear accelerator and Co-50 teletherapy measured. The effect of scattered radiation dose by protecting block was been ignored in radiation therapy, 2-3% of scattered radiation may be 90-200 cGy which could be influence vitial complications such as cataract, oligospermia or sterility. So that exect calculation of such scattered radiation especially for large field small protection of vitial organ is very important. The purpose of this article is to calculate scattered radiation by protecting block exactly for irregular field Linac or Co-60 irradiation and to applicate these data in clinical radiation field. Authors could obtain following results. 1. The lesser angle between shielding block showed more scattered radiation. 2. With decreasing distance between shielding blocks, the dependent of scattered radiation were increased. 3. Output of 18MeV Linear accelerator and Co-60 was related linear proportion on field size, but independent according to the size of shielding block in 18MeV Linear accelerator.

The primary treatment modality of malignant tumors of the nasopharynx is radiation therapy owing to its inaccessibility to surgical intervention. Over the last two decades there were many changes in techniques of delivery, which include the use of higher doses of radiotherapy, the use of wide radiation field, including the elective radiation of the whole neck, the combined use of brachy- and teletherapy, and the use of split-course therapy. In spite of these advances local and regional recurrences remain the major cause of death. As a boost therapy after external irradiation, high-dose-rate intracavitary irradiation using remote control afterloading system(RALS) was used in two patients. Our results were satisfactory, however, this procedure should only be performed by those who have developed enough expertise in the use of intracavitary techniques for the treatment of nasopharyngeal cancer and have a supportive team including a physicist, dosimetrist, nurse, and trained technologist.

Total 21 patients with airway obstruction from lung cancer treated with radiotherapy at Department of Therapeuctic Radiology, Yeungnam University College of Medicine, between April 1986 and December 1988 are retrospectively analysed by means of roentgenologic findings. Obtained results are as follows. 1. 15 out of 21 patients(71%) showed complete or partial response. 2. Patients with small cell lung cancer showed 100% response in spite of low dose(30GY/10 fractions). 3. Patients with non-small cell lung cancer treated with 50GY or over showed better response than below 45GY or below. 4. There is no relationship between the response and site of airway obstruction. These data suggested that high dose irradiation is more effective in the management of airway obstruction from lung cancer and meticulous radiotherapy planning with appropriate protection of normal lung and critical organs should be investigated in order to maximize radiation effect and minimize side effect, complication or sequelae.

Clinical estimation of bladder and rectal doses from high dose rate intracavitary irradiation in carcinoma of the cervix uteri has been initiated on a routine basis in an effort to obtain the optimum radiotherapeutic dose. Simulation films with contrast media are used to image the bladder and rectum, and dose rates are estimated at various interesting points with the aid of treatment planning computer, NEC Therac-2300. Fifty-three patients have been reviewed in order to ascertain the correlation between radiation dose at interesting points in the bladder and rectum and the dose at Point A and B. The dose ratio between doses at Point A 'and interesting points is an important clinical factor in evaluating the treatment planning. This also serves as documentation of the dose to normal structures within the treatment volume. Authors conclude that obtained data are within acceptable ranges and routine simulation films of the bladder and rectum after administration of contrast media with dose calculations at interesting points provide important information for optimizing radiotherapy planning in the treatment of cervical carcinoma without increased time and effort or patient's discomfort.