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To improve dose conformity and normal tissue sparing in patients with concave-shaped head and neck cancers by using tomotherapy and static step-and-shoot intensity-modulated radiation therapy (IMRT) and by comparing results with those of three-dimensional (3D) conformal radiation therapy (CRT) and two-dimensional (2D) radiation therapy.Treatment planning in 10 patients with concave-shaped head and neck tumors was performed by using tomotherapy and step-and-shoot IMRT, 3D CRT, and 2D techniques. IMRT plans were modified by placing "virtual critical structures" in regions outside the target where hot spots occurred. These modified plans were used for comparison because they provided better dose conformity. Critical structures were the spinal cord, the parotid glands, and the mandible. Comparisons were performed by means of dose-volume histograms, clinical target volume (CTV), target covered by 95% isodose (D(95%)), dose received by 5% of the critical structure volume (D(5%)), maximum dose, mean dose, and normal tissue complication probability for critical structures.Original IMRT plans showed more conformal dose distributions than those in 3D CRT and 2D plans. However, hot spots developed in the posterior and anterior neck. Introduction of virtual critical structures in IMRT plans resulted in removal of these hot spots without affecting target coverage. Modified IMRT plans also demonstrated better CTV coverage than that in 3D CRT and 2D plans. The average D(95%) was 97.3% with tomotherapy, 97.1% with step-and-shoot IMRT, 84.7% with 3D CRT, and 69.4% with 2D techniques. D(5%) for the spinal cord changed from approximately 45 Gy with 3D plans and 46 Gy with 2D plans to approximately 28 Gy with IMRT.IMRT demonstrated better target coverage and sparing of critical structures than that of 3D CRT and 2D techniques. Use of virtual critical structures resulted in removal of hot spots around the spinal cord.

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.

Untreated neoplasms of the neck (tumors of the oropharynx, supraglottic area, carotid body, and thyroid, in addition to malignant lymphadenopathy) were evaluated in 23 patients with magnetic resonance (MR) imaging. The results were compared with computed tomographic (CT) scans in 20 patients. Contrast between tumor and fat was best on relatively T1-weighted images (500/30-35 [TR msec/TE msec]), whereas separation of tumor and muscle was best with relatively T2-weighted pulse sequences (1,500/90). Balanced images (1,500/30-35) provided best overall image quality and best demonstrated vascular anatomy. MR imaging was usually superior to CT in showing the relationship of tumor mass to muscle. MR imaging and contrast material-enhanced CT were equivalent in most patients in defining vascular anatomy, but MR imaging was superior when intravenous contrast material was not administered. However, CT was more helpful in showing bone and cartilage anatomy, and in some patients CT also was better in showing airway abnormalities. Despite these limitations, MR imaging is a promising imaging technique for studying neoplasms of the neck.

Specific capillary blood flow and small-vessel pathology in animal tumors (rhabdomyosarcoma BA-1112) of WAG/Rij rats were examined following local tumor heating to 40-44.5 degrees C. Blood flow in tumors heated to 40-41 degrees C for 40 minutes was reduced initially by about 50%, but returned to near preheating values within 72 hours, consistent with the histopathological observations indicating small-vessel dilation and temporary congestion. The application of hyperthermia greater than 43 degrees C (for 40 minutes) resulted in the virtual elimination of capillary blood flow, consistent with pathological findings of widespread vessel rupture and hemorrhage in this temperature range.

A noninvasive technique employing photon activation of tissue oxygen in situ and detection of subsequent 15O positron decay was used to study the effects of single-dose 60Co irradiation on capillary blood flow in transplanted rat rhabdomyosarcomas. Tumor blood flow was measured before irradiation with 16.5, 38.5, or 60.5 Gy and at several intervals afterward (0-72 hr.). Pre-irradiation values of volume-averaged blood flow in the tumor ranged from 7 to 44 ml/min./100 g. Several hours after irradiation, blood flow fell by up to 50% for 60.5 Gy and up to 35% for 16.5 Gy. However, 24 hours after irradiation, tumor blood flow had recovered completely in the 16.5-Gy group and substantially in the others. For smaller doses such as the fractions typically employed in radiotherapy, no changes in tumor blood flow were observed.

Postoperative radiation therapy for lung cancer is still controversial. In a 9-year period, 69 patients with non-oat-cell carcinoma of the lung (16% stage I, 26% stage II, and 58% stage III) received such therapy. The radiation dose was less than 5,000 cGy in 42 patients, 5,000-5,900 cGy in 16, and 6,000 cGy or more in 11; follow-up ranged from 24 to 64 months. Actuarial survival at 2 and 4 years was 50% and 16%, respectively, for squamous cell carcinoma, and 40% and 26% for adenocarcinoma. The 5-year survival for stages I, II, and III cancer was 29%, 17%, and 19%, respectively. Histologic findings and type of surgery did not affect survival, but the radiation dose apparently did. The 3-year survival for patients who received less than 6,000 cGy was 35%, compared with 73% for patients who received higher doses. In eight patients, treatment failed within the irradiated volume: all had received doses of less than 6,000 cGy, and the volume in three was judged to be inadequate.

The computed tomographic (CT) scans of 80 patients with bronchogenic carcinoma classified as indeterminate for direct mediastinal invasion were retrospectively reviewed after the patients had undergone thoracotomy. Forty-eight (60%) of the masses were resectable, without invasion of the mediastinum, 18 (22%) focally invaded the mediastinum but were technically resectable, and 14 (18%) invaded the mediastinum and were not technically resectable. Although in most circumstances in this relatively small subset of patients CT was not helpful in differentiating masses with and without mediastinal invasion, CT was able to separate a large group of masses that were likely to be technically resectable. Thirty-six (97%) of 37 masses with one or more of these CT findings were considered technically resectable: contact of 3 cm or less with mediastinum, less than 90 degrees of contact with aorta, and mediastinal fat between mass and mediastinal structures. Of these 36 masses, 28 were resectable without mediastinal invasion, and eight were resectable with focal limited mediastinal invasion.

Thirty-three patients who had undergone prior surgery and/or radiation therapy for malignant neoplasms of the neck were studied with magnetic resonance (MR) imaging. Twenty-seven of these patients were also evaluated with computed tomography (CT). Ten patients were healthy posttreatment volunteers, and 23 had documented tumor recurrence. MR images better demonstrated normal muscular landmarks, especially in patients with obliterated fat planes. Areas of posttreatment fibrosis or scarring were low in signal intensity with all MR pulse sequences. However, in three patients, high signal intensity from postradiation edema of the supraglottic area mimicked neoplasm. In patients with recurrent tumor, MR imaging was superior to CT in defining the relationship of tumor and muscle and in demonstrating vascular anatomy when no intravenous contrast material was given during the CT examination. In two patients tumor and fibrosis were separated on MR images because of signal intensity differences. CT scans, however, showed adjacent bone and cartilage anatomy better. Our data indicate that an MR examination may be helpful in patients in whom CT is indeterminate either because of anatomical distortion or suboptimal demonstration of vascular anatomy.