The value of supraclavicular area treatment in radiotherapeutic management of lung cancer.
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Adenocarcinoma↗
Biomedical subjects
B Emami
Publications and source records attributed to B Emami.
Value of computed tomography in radiotherapy of lung cancer.
The effectiveness of CT scanning in radiotherapeutic treatment planning was evaluated in 32 patients with bronchogenic carcinoma. CT of the chest in pretreatment evaluation of these patients supplemented conventional clinical and radiographic patients supplemented conventional clinical and radiographic studies, resulting in (1) more clear delineation of tumor extent in 24 patients (75%); (2) change in assessment of the size of lesions in 14 patients (43%); (3) change of disease stage in 13 (40%); (4) demonstration of inadequacy of treatment plan in nine (28%); and (5) changes in the volume of normal tissue irradiated in 14 (40%). CT scan data was judged essential for treatment planning in 17 patients studied (53%). Unsuspected areas of tumor involvement were seen in 21 patients (65%). Use of the CT scan as a patient contour for radiotherapy treatment planning of lung cancer and alternative techniques are discussed.
Adult↗
Combined therapy of osteosarcoma: preoperative irradiation, surgery, and chemotherapy.
The rationale for prebiopsy and preoperative irradiation in a multimodal approach to treatment of osteosarcoma is presented. Six patients with osteosarcoma underwent preoperative irradiation, amputation, and elective chemotherapy. Five of these also received prebiopsy irradiation: three survive without metastases at 29, 36, and 56 months, with no therapy for 10, 16, and 37 months, respectively; two patients died at 6 and 19 months of pulmonary metastases which appeared at 2 and 10 months, respectively. The latter two did not receive prebiopsy irradiation. Another patient, whose pulmonary metastasis regressed at 6 months with adriamycin and was later resected, died of cardiac failure at 59 months without evident metastasis. Immunologic aspects of the disease are also discussed.
Adolescent↗
Surgery, chemotherapy and supervoltage radiotherapy for carcinoma of the ovary.
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Adenocarcinoma↗
Photon activation-15O decay studies of tumor blood flow.
A direct, noninvasive method for measuring absolute values of specific capillary blood flow in living tissue is described. The method is based on the photon activation, in situ, of tissue elements and the measurement of the subsequent decay of the positron activity induced, employing coincidence detection of the photon pairs produced in positron annihilation. Analysis of the time-dependent coincidence spectrum reveals the contribution to the total signal from the decay of 15O, from which the specific capillary blood flow in the imaged, activated volume is ultimately determined. By virtue of its introduction of the radioisotope of interest (15O) directly and uniformly into the tissue volume under investigation, the method described permits both the nonperfused and well perfused fractions of an activated volume to be estimated and hence, the average specific blood flow within imaged tumor volumes to be computed. The model employed to describe and analyze the data is discussed in detail. Results of application of the technique to measurement of specific blood flow in rhabdomyosarcoma tumors grown in WAG/Rij rats are presented and discussed. The method is shown to be reliable and well suited to studies designed to determined the effects of various agents, such as heat, radiation and drugs, on tumor blood flow.
Animals↗
Use of the Clinac-35 for tissue activation in noninvasive measurement of capillary blood flow.
Through adjustment of operating parameters responsible for the acceleration, steering, and focusing of electrons en route to the target, we have extracted a 30-MV x-ray beam from the Clinac-35 linear accelerator that is suitable for use in photon activation -15O decay studies of tissue perfusion. This beam is significantly more efficient than the "standard" 25-MV beam in producing 15O in situ through activation of tissue oxygen, thereby substantially reducing the dose to tissue required to yield a desired initial 15O activity. Production and characteristics of the higher energy beam are discussed, and data obtained from its application to measurement of capillary blood flow in animal tumors are presented and analyzed.
Animals↗
Nonsurgical treatment of advanced metastatic cervical disease in cancer of the larynx.
Historically, patients with advanced cervical adenopathy (N2 or N3) have between a 20 and 30% chance of surviving their disease at 5 years from treatment. Despite attempts at more aggressive surgical resection, including resection and reconstruction of the carotid artery, patients with advanced cervical adenopathy remain at the highest risk for the development of local recurrences and distant metastases. This chapter will review the current limitations of surgical resectability for advanced neck disease, discuss the evolution of combined chemoradiation therapy for these patients, and finally present promising recent technological advances in radiation oncology which will have significant impact on the treatment of these patients.
Combined Modality Therapy↗
Irradiation alone or combined with hyperthermia in the treatment of recurrent carcinoma of the breast in the chest wall: a nonrandomized comparison.
Tumour response and control (freedom from local relapse) were compared in two non-randomized groups of patients with recurrences from carcinoma of the breast (95 per cent in the chest wall and 5 per cent in the axillary or supraclavicular lymph nodes) receiving treatment at the Mallinckrodt Institute of Radiology. One group, comprising 48 patients treated between March 1978 and December 1984, received varying doses of irradiation (2000-4000 cGy in fractions of 400 cGy every 72 h) followed by local microwave hyperthermia (41-43 degrees C, 30-60 min). Irradiation was usually delivered with electrons ranging from 9 to 16 MeV. Hyperthermia was administered with 915 MHz external microwaves. The second group of 116 patients, with lesions similar to those treated with hyperthermia and irradiation, were treated with irradiation alone between January 1964 and December 1984. Doses of irradiation ranged from 2000 to 6000 cGy, usually delivered in daily fractions of 200-300 cGy TD. Irradiation was administered with Cobalt-60, 4 MeV photons or electrons (9-13 MeV) and occasionally with superficial X-rays. Patients with lesions 1-3 cm in diameter treated with irradiation and hyperthermia exhibited a complete tumour response rate of 80 per cent (12/15) while patients receiving irradiation alone had a complete response rate of 33 per cent (P = 0.04, Fisher exact test, two tail). The complete response rate for tumours larger than 3 cm treated with irradiation and heat was 65 per cent (13/20) compared to 42 per cent (18/43) for lesions receiving irradiation alone (P = 0.1, Fisher exact test, two tail).(ABSTRACT TRUNCATED AT 250 WORDS)
Breast Neoplasms↗
Interstitial thermoradiotherapy in treatment of malignant tumours.
From October 1981 to October 1985, 48 recurrent/persistent tumours (46 patients) were treated with a combination of interstitial hyperthermia and interstitial radiation therapy. All patients had failed other conventional treatment modalities. Radiation was administered using 192Ir with doses varying from 2000 to 6000 rad, depending on the dose of previous irradiation. Hyperthermia was administered with either localized current fields (LCF) or microwaves, two sessions each, minimum tumour temperature of 42.5 degrees C for 60 min. Of 37 lesions treated with at least one satisfactory hyperthermia session, there were 26 of 37 (70 per cent) complete responses and 11 of 37 (29.7 per cent) partial responses. Of 11 lesions with no sessions of satisfactory hyperthermia, there were no complete responses and only five partial responses. The detailed results are presented.
Adult↗
Thermoradiotherapy of malignant melanoma.
From 1978 through February 1986, 49 measurable lesions in 18 patients with recurrent primary or metastatic malignant melanomas were treated with a combination of radiation therapy and hyperthermia. The primary sites were head and neck (eight), chest wall (two), pelvis (one), upper extremities (three), and lower extremities (35). Because of the length of the study, the dose and fractionation of radiation therapy varied (dose per fraction from less than 400 cGy to 800 cGy and a total dose of 2000 cGy to 6000 cGy). This variation was mostly dependent on the prior course of radiation therapy of these lesions. The hyperthermia technique used in these patients was superficial local microwave hyperthermia; a minority of patients were treated with ultrasound. Complete response was achieved in 29 lesions (59.2 per cent) and partial response in six lesions (12 per cent). In a separate analysis of 67 lesions with superficial malignant melanoma who were treated by radiation therapy alone, a 24 per cent complete response and a 34 per cent partial response were achieved. Detailed analyses are presented in regard to dose per fraction, total radiation dose, and the size of lesions.
Combined Modality Therapy↗
SAR patterns of external 915 MHz microwave applicators.
Analysis of the results from recent clinical trials has shown that tumour size is a significant prognostic factor in eventual tumour control in patients treated with thermoradiotherapy. The critical issue appears to be the adequate coverage of hyperthermia target volume with 'therapeutic temperature'. Therefore one must choose appropriate applicators for the treatment of a given tumour. Accurate knowledge of performance characteristics of the applicators used in clinics thus becomes crucial. In an attempt to take the first step for the appropriate selection of applicators in clinics several commonly used applicators were evaluated according to their 75%, 50%, and 25% two-dimensional SAR (specific absorption rate) contours at depths of 1-3 cm. The data were subsequently approximated by rectangles. This type of information, even with its limitations, is extremely important in implementing quality assurance in hyperthermia. In this communication we will present such information, and the implications in current hyperthermia clinical trials will be discussed.
Biophysical Phenomena↗
Potential for localized, adjustable deep heating in soft-tissue environments with a 30-beam ultrasonic hyperthermia system.
Initial heating rates (degrees C/min) along parallel tracks at depths of 1-14 cm in a static, muscle-like phantom were determined from time-temperature profiles obtained with 'Helios', a 30-beam ultrasonic hyperthermia system developed by Varian Associates. Data were taken at a single operating frequency of 556 kHz, for different sets of focal plane ring diameters of the four-ring array applicator, different levels of transducer driving power and two different focal plane depths, 6 cm and 9 cm. In each experiment, at each point of temperature measurement, analysis of temperature versus time data over a 2 min heating interval permitted separation of the desired phantom heating from artefactual heating resulting primarily from absorption of transverse (shear) waves produced at phantom-metal probe catheter interfaces. The results of the studies conducted suggest that in a non-translating carriage mode, Helios can produce axially and laterally localized deep heating in soft tissues for tissue volumes of lateral dimension up to a minimum of 4 cm and tissue depths of at least 11 cm. The results obtained also suggest that Helios can produce laterally localized heating to tissue depths of at least 11 cm without excessive heating of superficial soft-tissue layers, for tissue volumes of lateral dimension up to a minimum of 8 cm. The methodology used in the phantom studies was applied to the production of localized heating in the right lobe of the liver of adult pigs. Temperature versus time profiles obtained in the in vivo studies indicated that, for the set of system parameters employed, concentration of ultrasonic power at greater depths in the liver (e.g. 10.5 cm versus 5 cm) could be achieved, suggesting that Helios should be able to produce localized heating of targeted hepatic volumes when its operating parameters are selected in accordance with effective treatment planning techniques.
Animals↗
Dual-antenna applicator for hyperthermia of tumours at intermediate depth.
A dual-antenna applicator with 21 x 26 cm2 aperture, that is fully loaded and operates at 74 MHz, was developed at the Mallinckrodt Institute of Radiology. By placing two antennas into an applicator capable of propagating TE10 mode, a significant enlargement of heating pattern was achieved without an increase in applicator dimensions. When antennas are placed symmetrically about a parallel to the antenna axis of symmetry, the sensitivity of the applicator input impedance to variations of load impedance reduces. Stable coupling of the RF power to the treatment area may be provided. Twenty patients with eccentrically located tumours were treated using this device.
Evaluation Studies as Topic↗
Evaluation of the Sigma 60 applicator for regional hyperthermia in terms of scattering parameters.
Scattering parameters adequately describe the interference between ports of a multiportal electromagnetic device when the device dimensions are comparable with the wavelength of the electromagnetic waves within the device. Since the Sigma 60 applicator is a four-port electromagnetic device, the interference between ports (quadrants) is described by a 4 x 4 scattering matrix. The load and frequency dependence of the scattering parameters were studied. The exact values of the parameters depends on the load within the applicator, but typically have minima at frequencies around 80 MHz and sometimes at 100-110 MHz. The effects of the coupling between quadrants can be substantial. Marked changes in the heating pattern can occur, particularly if the phase of the coupling element and the phase between quadrants both approach 90 degrees. Examples are shown in which the effects of coupling can qualitatively alter the intended SAR pattern. Simple steps which can be taken to minimize this phenomenon are demonstrated. Recommendations for clinical practice are discussed. Scattering parameters obtained with a non-absorbing phantom can be used for the quality assurance evaluation of the device.
Biophysical Phenomena↗
Phantom studies and preliminary clinical experience with the BSD 2000.
The BSD 2000 system is an array of microwave antennas operating in the 60-120 MHz range. It is a four-quadrant regional hyperthermia device with phase control permitting the operator to choose the point of constructive interference. A computer preplanning system is provided. We have compared the computer predictions with measured relative specific absorption rate (SAR) distributions in muscle equivalent phantoms and pig cadaver. The predicted SAR distribution is in qualitative agreement with observation, although differences of approximately 3-5 cm in the location of iso- SAR contours were noted. The longitudinal dependence of relative of distance cephalad to the central plane of the power distribution was measured, and it was found that a length of 15-20 cm was covered by the 50% iso-SAR. SAR measurements in the spinal canal of a pig cadaver showed that, even at resonance frequency, the measured SAR in the cervical spine was small (0.07 of central axis SAR). However, the spinal canal SAR as measured in the central plane of an evenly balanced configuration was 0.6 of the peak SAR. Marked reduction of the spinal canal SAR could be obtained with steering techniques and was in good agreement with the computer preplan. This paper reviews preliminary clinical experience with 17 patients. All but 2 patients were treated with steering techniques to permit partial sparing of normal tissues. The goal of maintaining central tumour temperature at or above 42 degrees C for at least 30 min was maintained in 41 of 67 sessions (61%) and in at least one session for all but 2 patients. Seventy-seven per cent of monitored tumor points attained at least 42 degrees C in patients for whom thermal mapping was performed. Significant cardiovascular stress developed during hyperthermia in two patients. There have been five complete responses and seven partial responses in the 17 patients.
Combined Modality Therapy↗
A phase I/II study to evaluate radiation therapy and hyperthermia for deep-seated tumours: a report of RTOG 89-08.
The purpose of this paper is to evaluate the safety and efficacy of deep hyperthermia in conjunction with radiation therapy. This study employed 'second generation' electromagnetic devices which were felt to be better able to confine heating and spare normal tissue than the devices evaluated in a previous study (RTOG 84-01). Sixty six patients at six institutions were enrolled on a prospective Phase I/II study. Eligible deep seated tumours were treated with a combination of external hyperthermia and radiation therapy. Radiation consisted of 1.7-2 Gy per fraction, 4-5 fractions per week, to > 20 Gy (previously irradiated lesions) or > 50 Gy (no previous radiation). Deep hyperthermia was delivered with electromagnetic devices: BSD 2000 for 92% of cases, Thermotron for 5% of cases, other low frequency electromagnetic for 4% of cases. Hyperthermia was delivered < or = twice weekly. Overall complete and partial response rates were 34% and 16% respectively. Response was not correlated with maximum tumour temperature or disease site. There was, however, a strong association with radiation dose: 54% CR with > or = 45 Gy versus 7% with < 45 Gy (p < 0.0001). The achieved temperatures were less than ideal. Although the average maximum tumor temperature was 41.9 degrees C (range 35.7 degrees C-46.7 degrees C), the minimum tumour temperatures were low. The average minimum tumour temperature was 38.5 degrees C and was never > 41.8 degrees C. Treatment was well tolerated with no fatalities. There were four acute grade 3 or 4 toxicities (6% of patients). Patient discomfort resulted in interruption or discontinuation of sessions in 30% of the sessions. In 12 cases (18% of patients) the planned course of hyperthermia was discontinued due to acute discomfort. The devices used in this study were better tolerated than the devices used in the previous Phase I/II deep hyperthermia trial (RTOG 84-01) with less patient discomfort and no problems with severe systemic cardiovascular stress. In the previous study 68% of the hyperthermia courses were prematurely terminated primarily due to patient discomfort and toxicity; in the present study 18% were prematurely terminated. However, as indicated by the low minimum tumour temperature, fundamental problems with achieving acceptable temperature distributions remain.
Adult↗