Peter Greenberg

The use of postoperative irradiation for the prevention of heterotopic bone formation after total hip replacement

Formation of heterotopic bone (HTB) following total hip replacement may partially or completely ankylose the joint space, causing pain and/or limiting the range of motion. Patients at high risk for formation of HTB postoperatively include those with previous HTB formation, heterotopic osteoarthritis, and active rheumatoid spondylitis. Patients in these high risk groups have a 63-69% incidence of post-operative HTB formation, usually seen radiographically by 2 months post-operation. From 1980-1986 twenty-nine hips in 28 consecutively treated patients were irradiated post-operatively at the UCLA Center for the Health Sciences. The indication for irradiation was documented HTB formation previously in 26 of the 27 hips presented below. From 1980-1982 patients received 20 Gray (Gy) in 2 Gy fractions; from 1982-1986 the dose was reduced to 10 Gy in 2 Gy fractions. Twenty-seven hips in 26 patients completed therapy and were available for evaluation, with a minimum of 2 month follow-up, and a median follow-up of 12 months. Three of 27 hips developed significant HTB (Brooker grade III or IV) post-operatively, whereas 5 of 27 hips developed minor, nonsymptomatic HTB (Brooker grade I). When irradiation was begun by postoperative day 4, 0 of 17 hips formed significant HTB. If irradiation began after post-operative day 4, 3 of 10 hips formed significant HTB (Brooker grade III or IV). These 3 hips received doses of 10 Gy in one hip and 20 Gy in the other 2 hips. There were no differences in the incidence or severity of side effects in the 10 Gy vs. the 20 Gy treatment groups. Eighteen hips received 10 Gy, 8 hips 20 Gy and, 1 hip 12 Gy. In conclusion, 10 Gy in 5 fractions appears as effective as 20 Gy in 10 fractions at preventing post-operative formation of HTB. For optimal results, treatment should begin as early as possible prior to post-operative day 4.

A Kinetic Evaluation of Blood—Brain Barrier Permeability in Human Brain Tumors with [68Ga]EDTA and Positron Computed Tomography

Twelve patients with primary and metastatic brain tumors were evaluated with [68Ga]ethylenediaminetetraacetate (EDTA) and positron computed tomography. Using a two-compartment tracer kinetic model, foward (K1) and reverse (k2) rate constants for molecular diffusion across the blood–brain barrier (BBB) were obtained and averaged 0.0029 ± 0.0016 (mean ± SD) ml/min/g for K1 and 0.0310 ± 0.0156 min−1 for k2. Most tracer kinetic models are based on the assumption that tissue radioactivity contains no vascular component or require independent measures of cerebral blood volume (CBV) which are then subtracted from the measure tissue activity. The model in this work differs from that approach by assuming a vascular compartment in the tissue kinetic data. This vascular parameter is estimated from sequential measurements of activity concentrations in regions with an intact BBB or from measurements of 68Ga concentrations in the plasma (the input function). Thus, this approach does not require the assumption of a zero vascular contribution, does not require a separate measurement of CBV, and uses the criteria of constrained estimation to provide estimates of the local CBV and molecular diffusion through the BBB. Estimates of the relative CBV of the lesions in four studies (three subjects) with [68Ga]EDTA correlated well with those obtained with the C15O hemoglobin technique (correlation coefficient of 0.97).

The treatment of solitary plasmacytoma of bone and extramedullary plasmacytoma

Eleven patients with solitary plasmacytoma of bone (SPB) and six patients with extramedullary plasmacytoma (EMP) were treated at the UCLA Center for the Health Sciences. Primary treatment in 14 of 17 patients was with radiation, while three patients were irradiated for recurrent disease. Eleven patients with SPB were irradiated with doses of 32–55 Gy, with 10 of 11 patients receiving doses of 40–55 Gy. Local control was achieved in 10 of 11 patients with SPB. One patient died with metastatic disease with unknown local status. Six patients with EMP were irradiated with doses of 38–56 Gy. Of these patients, two were locally controlled; one patient failed locally; one patient died during treatment; one patient died with local disease at 85 months after multiple resections, chemotherapy, and two courses of irradiation; and one patient was lost to follow-up. Progression to multiple myeloma was seen in 5 of 11 patients with SPB and in none of six patients with EMP. For patients with SPB, we recommend treating the entire bone to 40 Gy, with a boost when feasible. Patients with EMP receive the same dose, including the lymph nodes in tumors at high risk for spread. Radical surgical resections appear to be unwarranted.

Ewing's sarcoma metastatic to placenta

Summary In a case report of Ewings sarcoma with multiple metastases, histological findings of the placental involvement were demonstrated.

Treatment planning for particle radiation therapy.

Fast neutrons beams from the new medically dedicated cyclotrons in the US have depth dose characteristics comparable to photon beams from a 6-MV linear accelerator, at best. Treatment planning will have specific difficulties related to the relatively increased radiosensitivities of the brain, spinal cord, lens of the eye, and salivary gland. Therefore, exploitation of the potential biologic advantages compared to high energy photons will extract the price of increased difficulties in treatment planning. Dosimetric advantages of protons and helium ions compared to high energy photons are real and make possible the high-dose irradiation of cancers immediately adjacent to sensitive critical normal structures. Treatment planning and delivery with a precision of less than 2 mm is necessary. Such methods are already operational. Particle radiation therapy facilities are national resources, which can help the clinical radiation oncologist in the unique management of a few, specific problems.

Treatment of pathologically staged IIIA Hodgkin's disease

We have reviewed the records of 37 patients with pathologically staged MA Hodgkins disease, treated from 1970 to 1982. Twenty patients were staged IIIA1 and 17 staged IIIA2. Treatment consisted of total nodal irradiation in 33 patients (eight of whom received adjuvant MOPP), and mantle plus para-aortic irradiation in four patients (all of whom received adjuvant MOPP). Five-year relapse-free survival (RFS) in patients without splenic involvement was 77% versus 49% for those with splenic involvement (p = 0.43). Five-year RFS in patients treated with irradiation and chemotherapy (RT/ CT) was 76% vs. 47% for patients treated with irradiation alone (p = 0.12). RFS was not influenced by sex, mediastinal involvement by tumor, or anatomic substage. Overall survival (corrected for deaths due to intercurrent disease) for the entire group of patients was 92% at 5 years and 87% at 10 years. Sex, mediastinal or splenic involvement by tumor, therapy (RT vs. RT/CT), or anatomic substage did not significantly influence survival. We currently recommend RT/CT only for those patients with extensive splenic involvement and/or Stage IIIA2 disease. We feel that the poor prognosis of these patients justifies the use of RT/CT and its risk of second malignancies.