Three-dimensional treatment planning of intracavitary gynecologic implants: analysis of ten cases and implications for dose specification.

PURPOSE Results of 3-dimensional treatment planning for ten intracavitary gynecologic implants and implications for dose specification are presented. METHODS AND MATERIALS Using a computed tomographic (CT) compatible intracavitary applicator we have performed CT scans during gynecologic brachytherapy in 10 cases. A CT-based treatment planning system with 3-dimensional capabilities was used to calculate and display dose in three dimensions. Conventional point doses including the estimated bladder and rectal maximum doses and dose to Point A were acquired from orthogonal simulation films. CT maximum bladder and rectal doses and minimum cervix doses were ascertained from isodose lines displayed on individual CT images. Dose volume histograms for the bladder, rectum and cervix were generated and used to obtain volume of the cervix target volume receiving less than the prescribed dose and the volume of bladder and rectum receiving more than the orthogonal maximum doses. The 5 cc volume of bladder and rectum receiving the highest dose were also calculated. RESULTS Average values of CT point doses and volumes are compared with the traditionally obtained doses. As demonstrated by others, much higher bladder and rectal doses are found using the CT information. The minimum dose to the cervix target volume is lower than the dose to Point A in each case. CT maximum bladder and rectum and minimum cervix target doses may not be the best index doses to correlate with outcome because of the small volumes receiving the dose. CONCLUSION We hypothesize that clinically useful bladder, rectal and cervix target volume doses will include volume information which is obtainable with dose volume histogram analysis.

[1]  W. Newton,et al.  Value of computerized axial tomography in cervical cancer. , 1987, Oncology.

[2]  C. Moore,et al.  Bladder base dosage in patients undergoing intracavitary therapy. , 1986, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[3]  S. Soong,et al.  Radiation alone in the treatment of cancer of the uterine cervix: analysis of pelvic failure and dose response relationship. , 1989, International journal of radiation oncology, biology, physics.

[4]  C. Perez,et al.  Principles and Practice of Radiation Oncology , 1987 .

[5]  G. Fletcher,et al.  Complications in 831 patients with squamous cell carcinoma of the intact uterine cervix treated with 3,000 rads or more whole pelvis irradiation. , 1970, The American journal of roentgenology, radium therapy, and nuclear medicine.

[6]  C. Moore,et al.  The relationship between the bladder and the cervix in patients undergoing intracavitary therapy. , 1987, The British journal of radiology.

[7]  L. A. Parker,et al.  Computed tomography in the evaluation of clinical stage IB carcinoma of the cervix. , 1990, Gynecologic Oncology.

[8]  G. Hanks,et al.  Patterns of care outcome studies results of the national practice in cancer of the cervix , 1983, Cancer.

[9]  H. Kressel,et al.  Role of Computed Tomography in the Presurgical Evaluation of Carcinoma of the Cervix , 1981, Journal of computer assisted tomography.

[10]  T. Iversen,et al.  Stage IB carcinoma of the cervix, the Norwegian Radium Hospital: results and complications. III. Urinary and gastrointestinal complications. , 1983, Gynecologic oncology.

[11]  C. Orton,et al.  Dose dependence of complication rates in cervix cancer radiotherapy. , 1986, International journal of radiation oncology, biology, physics.

[12]  W. J. Meredith,et al.  Treatment of cancer of the cervix uteri, a revised Manchester method. , 1953, The British journal of radiology.

[13]  A. Dixon,et al.  A CT based dosimetry system for intracavitary therapy in carcinoma of the cervix. , 1987, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[14]  D. Brenner,et al.  Computed Tomography in Invasive Carcinoma of the Cervix: An Appraisal , 1983, Obstetrics and gynecology.

[15]  L. Anderson,et al.  Computation of radiation dose distributions for shielded cervical applicators. , 1985, International journal of radiation oncology, biology, physics.

[16]  M. Gillin,et al.  Carcinoma of the cervix: a time dose analysis of control and complications. , 1975, The American journal of roentgenology, radium therapy, and nuclear medicine.

[17]  D. Velkley,et al.  Routine clinical estimation of rectal, rectosigmoidal, and bladder doses from intracavitary brachytherapy in the treatment of carcinoma of the cervix. , 1981, International journal of radiation oncology, biology, physics.

[18]  M. Gray,et al.  Rectal and bladder injuries in relation to radiation dosage in carcinoma of the cervix. A 5 year follow-up. , 1961, American journal of obstetrics and gynecology.

[19]  R. Dresser,et al.  Carcinoma of the uterine cervix , 1945 .

[20]  J. Mizoe Analysis of the dose-volume histogram in uterine cervical cancer by diagnostic CT. , 1990, Strahlentherapie und Onkologie : Organ der Deutschen Rontgengesellschaft ... [et al].

[21]  D. McShan,et al.  A CT-compatible version of the Fletcher system intracavitary applicator: clinical application and 3-dimensional treatment planning. , 1989, International journal of radiation oncology, biology, physics.

[22]  Harold O. Wyckoff,et al.  International Commission ON Radiation Units and Measurements (ICRU). , 1974, The American journal of roentgenology, radium therapy, and nuclear medicine.

[23]  S. Kumari,et al.  Contribution of abdominal computer tomography (CT) in the management of gynecologic cancer: correlated study of CT image and gross surgical pathology. , 1980, Gynecologic oncology.

[24]  C C Ling,et al.  CT-assisted assessment of bladder and rectum dose in gynecological implants. , 1987, International journal of radiation oncology, biology, physics.

[25]  J. Dubois,et al.  Cancer of the uterine cervix: dosimetric guidelines for prevention of late rectal and rectosigmoid complications as a result of radiotherapeutic treatment. , 1982, International journal of radiation oncology, biology, physics.

[26]  N. Bjurstam,et al.  Computed tomography measurements of the cervix and distances to the bladder and rectum in intracavitary radiation treatment of gynaecological cancer. , 1983, Strahlentherapie.

[27]  V. Marcial Carcinoma of the cervix. Present status and future , 1977, Cancer.

[28]  H. L. Cox,et al.  CT for intracavitary radiotherapy planning. , 1980, AJR. American journal of roentgenology.

[29]  R. Mortel,et al.  Bladder and rectal complications following radiotherapy for cervix cancer. , 1988, Gynecologic oncology.