CT for intracavitary radiotherapy planning

Twenty-two patients with malignant uterine tumors were examined with computed tomography (CT) for treatment planning after insertion of an afterloading Fletcher applicator. The CT findings maximized the individualization of treatment planning, including the number, dosage, and loading arrangement of radioactive sources. Artifacts were produced by the metal; but in most cases the scans accurately portrayed the three-dimensional anatomic relationship of the applicator, uterus, and neighboring vital structures. The CT information made it possible to calculate dose distribution more rapidly and accurately for both intracavitary therapy and combined intracavitary and external therapy. Unsuspected uterine perforation was detected by CT in one case.     

A rapid radiotherapy planning program in intracavitary afterloading therapy

A recently developed program for the irradiation planning of intracavitary afterloading applications in the treatment of gynecological diseases is presented. On the basis of measured data, a rapid algorithm for calculating the dose within the field near to ray emitters is introduced which avoids any uncertainties as to the greatest activity and the dose rate constant. Distance- and direction-dependent corrections of the inverse square law are performed by means of polynomials easy to calculate or by tables. The structure and performance of the program are described. Some examples are given in order to illustrate the possible applications of the irradiation planning program.     

Prognosis and radiotherapy of endometrial carcinoma

The increase in the occurrence of corpus carcinoma and the influence that special problems (accompanying diseases, age, histology, radiation technique) have on the survival of the patient make it necessary to reconsider indication and technique in radiation. Even though 80% of the cases are in stage I which indicates a favourable prognosis for surgical treatment, many new therapeutical questions have presented themselves and should not, in the future, need to be answered by the experience in clinics or in medical centers alone. Patients with corpus carcinoma should therefore not be treated on the basis of a fixed program, rather, through a flexible program suited to the individual patient's needs. Aside from the demands for precise histological diagnosis (including grading) and better grouping of the stages (pelvic and paraaortic lymphnode involvement in stage I at least 10%, in stage II 40%!) future analysis should be improved, resulting in a decision for higher grading or an increase of the dose in radiation therapy of the tumor in the 2. and 3. stages. In order to accomplish this, better techniques in radiation therapy and communication with the gynecologists and pathologists is necessary, so that a mutual concept for therapy, improving the chances of cure can be developed. Proof that this is entirely possible can be seen in statistics of the last years (Annual Report 1981, results from Department of Gynecology, Freiburg i. Br.).     

Treatment of inoperable endometrial carcinoma with intracavitary high-dose rate iridium irradiation

Surgery should be an integral part of the management of the patient with endometrial cancer. Only patients with severe medical conditions should be treated with radiation therapy alone. Although radiation therapy alone often can cure endometrial cancer, five-year-survival figures are poorer than for operation. At the University of Vienna, I. Department of Gynecology, 198 patients with endometrial cancer were treated by radiation therapy alone. Using the afterloading-iridium-192-technique, the three-year-survival-rate was 76%, five-year-survival 60%. A comparable group of 185 cases treated by intracavitary radium-226 had five-year-survival of only 40% (p less than 0.001). With afterloading high-dose irradiation younger patients had five-year-survival of 75%, older patients (70 years and more) 51%; when tumor grading was one survival figures reached 76%, with tumor grading 2 and 3 only 41%. Severe radiation side effects did not occur with the optimal intrauterine single dose of 850 cGy (four times) and 700 cGy intravaginal (once), nor could any severe complications be observed when the total rectal dose did not exceed 500 cGy. In only 8% of the cases the treatment was combined with external irradiation (Cobalt-60). Intrauterine and intravaginal applications were performed without anaesthesia and the hospitalisation time was very short.     

The value of and indications for radiotherapy in endometrial carcinoma

Today the endometrial carcinoma is the most frequent malignant tumor found in female genital tract. Endometrial carcinoma ought to be operated in all cases, if possible. Traditionally some form of adjuvant radiotherapy has been given. Despite the large number of patients treated by combined therapy over the last 30 years, surprisingly there is a lack of hard data on which to establish a theory for an improved outcome. It is generally accepted that the risk of local relapses in the vagina is lowered when postoperative vaginal irradiation is applied. The question of the value of additional external irradiation in stage I endometrial cancer still is unsettled. Only two prospective studies led to the conclusion that only patients with poorly differentiated tumors and with deep infiltration of the myometrium might benefit from additional external radiotherapy. Therefore a simple score for these risk factors is proposed enabling assignment into patient groups of similar risk on the base of a point system due to individual prognostic factors. With a score of one to two points prognosis is very good and adjuvant irradiation seems not to be necessary. With three to four points local vaginal irradiation is recommended, with five and more points additionally external beam irradiation to the pelvis should be given. This is necessary in more than the half of the operated cases of endometrial carcinoma. The indication for such a treatment has become more individual and "high risk" cases are treated more intensively, but "low risk" cases have to be excepted from unnecessary adjuvant therapy. In order to judge an individual case of endometrial cancer histopathologic prognosticators have to be considered. Typical adenocarcinomas have a five-year survival of more than 80%, but unfavourable subtypes (adenosquamous, clear-cell, serous-papillary carcinomas) of only 40%, respectively. Tumor grading and depth of myometrial invasion are of high importance for individual prognosis. The new histopathologic staging system of FIGO (1988) takes these items into account. Only patients with severe internal diseases should be treated with radiation therapy alone. Although radiation therapy alone can cure endometrial cancer (five-year-survival approximately 60%), the survival figures are poorer than for the operation (five-year survival 80%, respectively). It should be outlined that in inoperable cases radiotherapy is the best form of treatment.     

Use of endoscopic mucosal clips in radiotherapy planning for oesophageal carcinoma: a series of three cases

This paper describes the technique of placing endoscopic mucosal clips to localize oesophageal carcinoma and hence facilitate radiotherapy planning. This technique has been used on three patients in our centre. One was treated radically with external beam radiotherapy and two were treated palliatively (retreatment) with intraluminal brachytherapy. Mucosal hemoclips were placed at the time of endoscopy to indicate the superior and inferior extent of the tumour. The clips provided a radiologically-recognisable marker of the tumour extent and were visible on simulation films or planning CT scans. The radiation portal included the tumour as demarcated by the clips with an adequate margin. There were no complications related to the placement of the clips. All patients completed the radiotherapy course as planned.     

颈部超声在分化型甲状腺癌131I治疗中的应用进展

分化型甲状腺癌是内分泌系统最常见的恶性肿瘤,其发病率呈逐年上升的趋势.其中,乳头状癌易发生颈部淋巴结转移.超声和超声引导下细针穿刺在颈部淋巴结转移检测方面具有很高的灵敏度和特异度.准确判断颈部淋巴结的性质对决定是否再次手术或131I治疗,以及131I治疗后的随访均有重要意义.     

Use of a programmable pocket calculator in radiotherapy treatment planning.

Software packages for a programmable pocket calculator have been developed for use in dosimetry. Using a field equation and a mathematical model of the beam profile, one can find the dose delivered to any point within the irradiated volume. Use of these programs for simple field calculations allows the radiologist to concentrate on more complex treatment plans.     

Use of digitally reconstructed radiographs in radiotherapy treatment planning and verification

The authors present 3 years of experience in using digitally reconstructed radiographs (DRR) for radiotherapy planning and verification. Comparison is made with simulation film (SF), to illustrate the advantages of DRR over SF. Emphasis is placed on using the appropriate equipment and applying the correct technique. A brief discourse on the principle of CT imaging is presented to illustrate the operation of CT software and optimization of image display for axial slices and DRR. Emphasis is placed on the application of clinical knowledge to enhance the usefulness, as well as the technical quality, of the DRR. Illustrative examples are given.     

Magnetic resonance for radiotherapy management and treatment planning in prostatic carcinoma

MRI has an important role for radiotherapy (RT) treatment planning in prostate cancer (PCa) providing accurate visualization of the dominant intraprostatic lesion (DIL) and locoregional anatomy, assessment of local staging and depiction of implanted devices. MRI enables the radiation oncologist to optimize RT planning by better defining target tumour volumes (thereby increasing local tumour control), as well as decreasing morbidity (by minimizing the dose to adjacent normal structures). Using MRI, radiation oncologists can define the DIL for delivery of boost doses of RT using a variety of techniques including: stereotactic body radiotherapy, intensity-modulated radiotherapy, proton RT or brachytherapy to improve tumour control. Radiologists require a familiarity with the different RT methods used to treat PCa, as well as an understanding of the advantages and disadvantages of the various MR pulse sequences available for RT planning in order to provide an optimal multidisciplinary RT treatment approach to PCa. Understanding the expected post-RT appearance of the prostate and typical characteristics of local tumour recurrence is also important because MRI is rapidly becoming an integral component for diagnosis, image-guided histological sampling and treatment planning in the setting of biochemical failure after RT or surgery.     

Local-regional staging of endometrial carcinoma: role of MR imaging in surgical planning

PURPOSE: To assess magnetic resonance (MR) imaging in depicting the depth of myometrial infiltration, cervical invasion, and presence of enlarged lymph nodes in patients with endometrial adenocarcinoma compared with surgicopathologic findings. MATERIALS AND METHODS: Thirty-seven consecutive patients with endometrial carcinoma were included in this prospective study. All patients underwent MR imaging and surgery. Qualitative image analysis included the depth of myometrial infiltration, infiltration of the uterine cervix, and presence of enlarged lymph nodes. Quantitative image analysis included tumor and myometrium contrast-to-noise ratios during different phases of dynamic imaging. MR imaging findings were compared with surgicopathologic findings. Sensitivity, specificity, diagnostic accuracy, and positive and negative predictive values of MR imaging in depicting myometrial and cervical infiltration and in lymph node assessment were calculated. RESULTS: Respective sensitivity, specificity, diagnostic accuracy, and positive and negative predictive values in assessing myometrial infiltration were 87%, 91%, 89%, 87%, and 91%; those for cervical infiltration, 80%, 96%, 92%, 89%, and 93%; and those for lymph node assessment, 50%, 95%, 90%, 50%, and 95%. There was significant agreement between MR imaging and surgicopathologic findings in assessment of myometrial invasion (P <.001). Myometrial and cervical invasion and lymph node enlargement were correctly assessed with MR imaging in 28 (76%) of 37 patients. Quantitative analysis showed a significant improvement in tumor and myometrium contrast-to-noise ratios during the equilibrium phase compared with the arterial and precontrast phases (P <.001). CONCLUSION: MR imaging coupled with contrast material-enhanced dynamic MR imaging is highly accurate in local-regional staging of endometrial carcinoma; more challenging is the assessment of pelvic and lumboaortic lymph nodes.     

Comparison of tumor regression rate of uterine cervical squamous cell carcinoma during external beam and intracavitary radiotherapy

Purpose  We compared the radioresponse of cervical carcinoma that was closely related to local disease control by the tumor regression rate (RR) during intracavitary radiotherapy (ICRT) and external beam radiotherapy (EBRT) on the presumption that ICRT has a stronger treatment impact than EBRT because of its specific dose distribution. Materials and methods  A total of 37 patients were treated by EBRT at 45.0 Gy over 5 weeks, followed by high-dose-rate ICRT at 6.0 Gy per weekly insertion at point A three to five times and by boost EBRT. RR was defined as the slope (day⁻¹) of the tumor-volume shrinkage curve fit to an exponential regression equation. Assuming that the tumors were ellipsoid, the tumor volume was estimated using magnetic resonance (MR) images obtained before treatment, after 45.0 Gy of EBRT, and after the third ICRT insertion. RRs were compared based on the radiotherapy method. Results  RR ranged between −0.008 to 0.093 day⁻¹ (median 0.021 day⁻¹) during EBRT and −0.001 to 0.097 day⁻¹ (median 0.018 day⁻¹) during ICRT, showing no significant difference or correlation between treatments. Conclusion  Contrary to expectations, RR did not directly relate to the impact of physical treatment. RR could be related to biological factors, such as the amount of tumor clearance and changes in tumor consistency during treatment.     

Long term results of Cathetron high dose rate intracavitary radiotherapy in the treatment of carcinoma of the cervix.

Between 1967 and 1974, 371 patients with carcinoma of the cervix have been treated by a combination of external beam radiotherapy and fractionated high dose rate brachytherapy using the Cathetron. A retrospective review was undertaken in 1986 and median follow-up time was 6 years. Life table analysis of survival and complications to 16 years was undertaken. International Federation of Gynaecology and Obstetrics (FIGO) stage distribution was 26%, 46% and 28% for Stages I, II and III, respectively, and 5 year survival was likewise 94% 63% and 37%. Age and histological type or grade were not found to influence survival. Recurrent disease was recorded in 142 patients; the first site was within the pelvis in 25% and as distant metastases in 17%. Following development of pelvic recurrence median survival was 28 weeks. Salvage surgery was performed in 32 patients, of whom five probably obtained survival benefit. Significant late morbidity was seen in a total of 71 patients (19%); in seven patients this was at more than one site. Late morbidity to the small bowel was recorded as Grade 2 in 10 patients and Grade 3 in 13; to the rectum, Grade 2 in 10 patients and Grade 3 in two patients; to the bladder, Grade 2 in 15 patients and to the vagina Grade 2 in 29 patients. Median time to onset for small bowel morbidity was 14 months, for rectum 18 months, for vagina 20 months and for bladder 52 months. 82% of all late morbidity had been seen by 5 years of follow-up, no case of late morbidity of recurrence was seen between 11 and 18 years of follow-up. These results are comparable to those reported for other methods in use at the time the patients were treated.     

Optimization of intracavitary radiotherapy of uterine cancer by intrauterine sonography

Until now the evolution of irradiation planning has above all considered the individual situation in the small pelvis, because there was no reliable diagnostic method to discern the infiltration within the myometrium. Intra-uterine sonography allows an exact presentation of the tumor infiltration within the myometrium. Thus the target volume for intracavitary therapy can be defined. Besides an optimal irradiation planning, a rapid and reliable diagnosis of a Via falsa as well as an estimation of regions especially endangered by perforations are possible.