Vaginal Cylinder Research Articles

Radiation tolerance of the vaginal mucosa

Sixteen patients with cancer of the vagina that were controlled locally for a minimum of eighteen months after teletherapy (T) or brachytherapy (B) or both (T & B), were analyzed for radiation tolerance of the vaginal mucosa. The site of vaginal necrosis did not always coincide with the site of the tumor. The posterior wall appeared more vulnerable than the anterior or lateral walls. For the distal vaginal mucosa, necrosis requiring surgical intervention occurred following combined T & B, if summated rad exceeded 9800. The upper vagina tolerated higher dosages. No patient required surgery for upper vaginal necrosis even though summated (T & B) dosage up to 14,000 rad was applied. Placing radioactive needles on the surface of the vaginal cylinder with or without interstitial perinea) needles should be avoided. Further accumulation of data is needed to define these vaginal mucosa tolerance limits more closely.

Dose rates for brachytherapy applicators using 137Cs sources

We have computed the dose rates from brachytherapy 3M 137Cs sources for different size ovoids and vaginal cylinders. They are expressed in tabular form. The dose rate tables thus generated compared with the widely used tables for 266Ra differ by as much as 9% for ovoids and up to 20% for the cylinders. ' These differences are mainly a consequence of differences in physical structure of the two types of sources. These tables will serve as a quick guide and reference and should be of great practical use to physicists and radiotherapists for planning implants. However, these tables are not meant to replace detailed computer isodose calculations.

A NEW AFTER-LOADING APPLICATOR FOR TREATMENT OF CANCER OF THE CERVIX AND VAGINA

An after-loading vaginal cylinder is described which a affords contracervical source application. It may be combined with a modified Fletcher tandem for radiation therapy of uterine, cervical and vaginal cancer. It offers flexibility for treatment of complex female genital tract lesions, is simple to apply and radiation exposure of personnel is virtually eliminated.

Afterloading vaginal irradiators.

The authors describe a set of vaginal cylinders of variable diameter (2 to 5 cm) and of adaptable length. With these almost any vagina may be fitted at the time of surgery, and exposure to personnel is eliminated. Lead may be incorporated in the cylinders to partially shield either the vagina or the rectum.

Examination of the Genital Organs in the Prepubescent and in the Adolescent Girl

To report the technical aspects of customized high-dose-rate brachytherapy for vaginal rhabdomyosarcoma using MRI- and CT-based planning in a 20-month-old girl.An impression of the vaginal cavity at the resection site was taken after adequate lubrication of the vagina with lidocaine jelly. The impression was processed in the dental laboratory to obtain an MRI-compatible device with three imbedded catheters 0.4 mm apart, assuring tumor coverage. An MRI- and CT-based simulation under anesthesia with the applicator in place were performed, and the images were registered for contouring and planning to deliver 40 Gy in 10 fractions daily. Dose to the ovaries was limited to a mean dose less than 4 Gy. Treatment was delivered daily under anesthesia with no acute complications.Brachytherapy using a customized applicator has many advantages over prefabricated vaginal cylinders for young girls. It allows greater dose distribution conformality with the possibility of contralateral vaginal wall sparing and more reproducible daily positioning. MRI-based planning is mainly performed to facilitate delineation of the target volume and the ovaries, which are easily identified on MRI.The customized applicator offers many advantages of which treatment reproducibility, inherent MRI compatibility, and excellent dose distribution conformality. Our brachytherapy technique using MRI and CT scan planning allows precise tumor and normal tissues delineation resulting in excellent tumor coverage and normal tissues sparing.

Treatment of rare lesions of the uterus and vagina.

Last year, while treating patients with cervical cancer, we were surprised to find a primary lymphosarcoma of the cervix. The patient received radium therapy as given for the more usual types of cancer, and the lesion has responded satisfactorily to date. This aroused our interest in the rare types of malignant disease of the female pelvic organs, for, although they are so seldom encountered, a radiologist may find himself called upon to treat such conditions at any time. Lack of experience with malignant lesions other than squamous-cell carcinoma, adenocarcinoma, or mixtures of the two, makes correct treatment a problem. One wonders how often these rare tumors occur and whether they respond to treatment which has been found effective for the more usual types of cancer. The rare pelvic cancers treated at the Mayo Clinic during the decade 1935–44 were selected for study. Excised tissue was resectioned, stained, and restudied in all cases. The complaints which brought these patients with unusual pelvic tumors to their physicians differed in no particular from the signs and symptoms of the more usual types of cancer; vaginal bleeding and discharge were the main complaints in nearly all instances. In many of the lesions of the corpus the bleeding was postmenopausal. Radium and roentgen therapy played a minor role in treatment. Nearly all of the tumors under study, with the exception of the hemangioendotheliomas, are known to be resistant to irradiation (1, 2). For malignant lesions of the cervix an intensive broken-dose method is employed, irradiating the entire cervical canal, vaginal cavity, and endometrium, with about eight applications of radium over a period of three or four weeks. This was supplemented by roentgen therapy to four pelvic ports, at 200 kv., giving 540 r (measured in air) to each port in four days, during the ten-year period under consideration. The roentgen therapy was generally repeated in three months. Treatment of primary vaginal cancers is highly individualized, owing to the variations in extent of the cancer. Superficial areas are treated with plaques of radium containing two or three tubes of 50 mg. each in parallel arrangement, the walls of the plaques consisting of 1.0 mm. of plastic. The dose is of the order of 80 mg. hr. per square centimeter of surface covered, which delivers a surface dose of 11,500 gamma roentgens, and a dose at a depth of 1 cm. of 1,800 gamma roentgens. When a greater depth dose is desired, additional radium, in cylinders of 1.1 cm. wall thickness, is employed against the malignant tissue for 700 mg. hr. per area, delivering a dose of 1,100 gamma roentgens at a depth of 1 cm. (3). Lesions of the corpus were usually treated postoperatively, in the hope of sterilizing any remaining malignant cells. Vaginal cylinders containing radium were mainly employed, plus roentgen therapy around the pelvis.

Plastic vaginal cylinder; accessory to the expanding cervico-uterine radium applicator.

In the management of carcinoma of the cervix, unless the multiple distributions of the radium intensities in the uterine canal and vaginal vault are controlled both mechanically and physically, thereby facilitating accurate duplication of the dose in gamma roentgens (or their equivalent) at two or more fixed distant pelvic points (A/B r coefficient of absorption), the clinical reporting of results and the technical evaluation and comparison of the different technics are of questionable statistical value. In previous studies we presented data relating to the photometric radiation effects upon slow emulsion films of supposedly standard radium technics and observed that there was a greater lack of uniformity and distribution of the pelvic radiation intensities than we had anticipated. This was found to be due in part to faulty positioning of the radium capsules, although at the time of our application we, like other therapists, had egotistically assumed confidence in our ability to pack accurately and fix permanently these loose radium sources in relation to the primary and potential malignant parametrial lesions. Routine radiographic examinations of the pelvis soon revealed that these wandering radium capsules were drifting into dangerous positions, toward the bladder or rectum. In the interest of protection of the normal structures, we removed and re-applied the radium in an attempt to correct these faulty positions, usually without success. Vaginal deformities or uterine displacements, or both, added to the difficulty of these reapplications. Our only alternative, if we hoped to avoid “hot-spots” and the probable development of slow healing ulcers or vaginal fistulas, was to reduce the total radium dose when the radiographic examination indicated that the loose capsules continued to remain in a position dangerous to normal pelvic tissues. In Figure 1 three removable radium tubes are shown, completely filling the uterine canal, with six vertical capsules uniformly distributed throughout the vaginal vault, designed, when fully expanded, to partially surround the lesion at the cervical os as well as to irradiate directly the parametrial fields. The two lateral vaginal capsules are removable. When the plastic cylinder, B, is attached to the protruding handle of the radium applicator it not only protects the outer half of the vaginal mucosa, but also serves as a fulcrum for effective and safer control of the radium sources in the mid-pelvic corridor between the bladder and rectum. In Figure 2, the expanding radium sources are viewed in the opposite lateral position within the pelvis. The respective ends, G, of the vaginal capsules are protected with lead and 2 mm. of brass. The radium needles have an over-all length of 19 mm. and an active radium length of 12 mm.