David O. Findley

Total skin electron irradiation for mycosis fungoides: relationship between acute toxicities and measured dose at different anatomic sites

From June 1978 to June 1986, 50 patients with primary and recurrent mycosis fungoides were treated with total skin electron irradiation (TSEI), using the Stanford technique, to a total dose of 3600 cGy. TSEI was used alone, or in combination with low dose total body photon irradiation, or MOPP. Thermoluminescent dosimeter (TLD) measurements of the prescribed skin dose were obtained on twenty patients. The dorsum of the foot was 24% higher. The axillae, the bottom, and the arch of the foot were significantly underdosed. Frequencies of acute toxicities noted at 2000 cGy were: Skin, Grade I-II (RTOG) 80%. Partial epilation: scalp, 100%; eyebrows and at eyelashes, 20%. Nail dystrophy, 48%. Edema: hands and feet, 44%. Bullae: dorsum of feet, 8%; hands, 4%; and 3600 cGy: Skin, grade III 22%. Total epilation: scalp, 66%; eyebrows and eyelashes, 56%. Nail loss, 38%. Edema: hands and feet, 76%. Bullae: dorsum of feet, 34%; hands, 12%. Conjunctivitis, 4%. Large bullae, were more significant on the dorsum of the feet. Severe moist desquamation occurred in eight patients who had ulcerated lesions on initial presentation. Three patients were hospitalized due to ulceration and skin infection. All patients completed treatment after a short to moderate break. No patient developed skin necrosis, or corneal ulceration. No correlation exists between dose level, degree and onset of toxicity with previous chemotherapy or TBI. We conclude that the overall toxicity of TSEI is well tolerated.

Intracatheter hyperthermia and iridium-192 radiotherapy in the treatment of bile duct carcinoma.

We report a case of a patient with locally advanced bile duct carcinoma treated with 4500 cGy external beam radiotherapy, followed 3 weeks later by intracatheter 915 MHz microwave hyperthermia and radiotherapy delivered through a biliary U-tube placed at the time of surgery. Heating was to 43-45 degrees C for 1 hour followed immediately by intracatheter Iridium-192 seeds to deliver 5000 cGy over a 72 hour period. Prior to treatment, a thermal dosimetry study in phanton was conducted, using the same type of U-tube catheter tubing as in the patient. Orthogonal X rays of the patients porta hepatis region were used to reconstruct the catheter geometry in the phantom. Proper insertion depth was determined thermographically to obtain maximum heating at the center of the tumor. The maximum SAR was 8.8 watts per kilogram per watt input. During the treatment, the average power applied was 30 W. Six months after therapy, the patient is asymptomatic. Although alkaline phosphatase, SGOT and SGPT have remained elevated, bilirubin has returned to normal and computerized tomographic scans and cholangiograms remain stable. A duodenal ulcer developed after therapy and is healing well with conservative medical management. This case demonstrates that hyperthermia applied through biliary drainage catheters is technically feasible and clinically tolerated. We believe the use of intracatheter hyperthermia in conjunction with external and/or intracatheter radiotherapy in selected patients with unresectable bile duct carcinomas warrants further study.

Use of variable thickness bolus to control electron beam penetration in chest wall irradiation

Abstract Construction of a variable thickness bolus modifies the electron beam penetration to accomodate differences in target thickness. This technique reduces the integral dose to underlying sensitive normal tissues, and permits increased flexibility in dose delivery to the designated volume. The technique has been found useful in electron beam irradiation of large chest wall lesions in 18 patients with recurrent, residual or suspected breast carcinoma post-mastectomy. The great flexibility shows individually tailored therapy. Patients tolerate the 5006–5600 rad delivered to the skin and the 4000–4500 delivered at depth in 6 weeks. Except for skin, which is at risk, there are no adverse reactions. Residual disease received local boost irradiation. The pattern of response following this program is similar to that found for photon therapy.

Total body irradiation with a 10 mv linear accelerator in conjunction with bone marrow transplantation

Abstract Total body irradiation (1000 rad, single dose) in conjunction with chemotherapy and bone marrow transplantation is a therapy for acute leukemia. We show that a 10 MV linear accelerator is a suitable source of radiation for these procedures. Dosimetric and clinical results are presented for 25 patients who were treated between l576 and 1278.

Dosimetry of a dual photon energy linear accelerator

We describe the dosimetric characteristics of a newly introduced dual photon energy linear accelerator, the Varian Clinac 1800. Depth doses are compared with other accelerators of the same nominal accelerating potentials (6 and 10 MV). Field flatness at dmax and at 10 cm depth, depth of dmax, wedge characteristics, output factors, and doses in the buildup region are presented.

Fractionated total body irradiation and high dose cyclophosphamide: a preparative regimen for bone marrow transplantation for patients with hematologic malignancies in first complete remission

SummaryWe treated 73 patients with hematologic malignancies in first complete remission (acute lymphoblastic leukemia = 23 patients; acute nonlymphoblastic leukemia = 25 patients; chronic myelogenous leukemia in first chronic phase = 20 patients, and high grade lymphoma = five patients) with a uniform preparative regimen consisting of fractionated total body irradiation (1 320 cGy) and high dose cyclophosphamide (100 mg/kg), followed by allogeneic bone marrow transplantation. By radiation dosimetry we demonstrated that the calculated doses were delivered accurately and reproducibly. Actuarial survival rates (± SEM) in complete remission were as follows: Acute lymphoblastic leukemia = 74±9%; acute nonlymphoblastic leukemia = 50±11%; and chronic myelogenous leukemia = 55±11%. Actuarial relapse rates for these three diagnoses were 19±9%, 17±11%, and 0% respectively. Three of the five lymphoma patients are alive in complete remission at 22+, 28+, and 54+ months. Overall probability of survival for the 73 patients was 59±7%. Interstitial pneumonia, usually associated with cytomegalovirus infection and graft-versus-host disease, and relapse of the underlying malignancy were the major causes of death.

Attenuation in Lipowitz’s metal of x rays produced at 2, 4, 10, and 18 MV and gamma rays from cobalt‐60

Attenuation in Lipowitzs metal of x rays produced at 2, 4, 10, and 18 MV and gamma rays from cobalt 60 were measured to the 1% level with a narrow beam geometry. Blocks made from standard styrofoam mold (7.6 cm thick) would reduce these primary beams by 95% to 99%.

Dosimetry of single fraction high dose total body irradiation as measured by thermoluminescent dosimeters

Eighty-five patients with acute myelogenous or acute lymphoblastic leukemia were treated at the City of Hope National Medicine Center with chemotherapy, total body irradiation, and bone marrow transplant. The average mid-line dose to these patients was 1002 rad with a uniformity of 8%.

Routine quality control of Ir-192 sources: Results of 46 months of surveillance☆

Documented problems with loose and inert Ir-192 seeds in nylon ribbons prompted us to develop a quality control program. Several problem cases are illustrated. A sample of ribbons from each shipment is measured in a radioisotope dose calibrator. Results of the measurements over a 46-month period are presented.

A simplified alternative to orthogonal field overlap when irradiating a tracheostomy stoma or the hypopharynx

Abstract Orthogonal field arrangements are usually employed to irradiate a tumor volume which includes a tracheostomy stoma or the hypopharynx. This approach may produce a significantly greater dose than intended to a small segment of the cervical spinal cord because of field overlap at depth from divergence of the beams. Various sophisticated approaches have been proposed to compensate for this overlap. All require marked precision in reproducing the fields on a daily basis. We propose a simplified approach of initially irradiating the entire treatment volume by saterior and posterior opposed fields. Opposed lateral fields that exclude the spinal cord would then provide local boost treatment. A case example and computer-generated isodose curves are presented.