Evaluation of multileaf collimator design for a photon beam

Various aspects of multileaf collimator (MLC) design are examined relative to clinical requirements. The characteristics studied included: (a) irregular field edge definition or "effective" penumbra, (b) optimum field coverage for the multileaf portion of the field, and (c) leaf velocity. A film dosimetry technique was developed to measure the rapid 2-dimensional change in dose at an edge defined by a multileaf collimator with the segments staggered. The method applies a correction factor which allows for the changing ratio of scattered to primary photons at the field edge so that the energy dependence of the film is corrected. Stepped lead alloy blocks were irradiated with 6 MV photons to obtain films simulating a double-focused multileaf collimator, and the results were compared to films of fields shaped with standard divergent blocks. The effect of the shape of the leaf face (the end of the leaf) on penumbra was also studied. Proper shaping of the leaf ends may eliminate the need to exactly match beam divergence so that the mechanical of the collimator system is simplified. Leaves having several different end shapes and moving horizontally to intercept a vertical beam were compared to the divergent design where a straight face moves along an arc. The measurements showed that the "effective" penumbra (measured as the distance from the 80 to 20% isodose lines) for the multileaf collimator is a function of the angle between the direction of leaf motion and the edge defined by the leaves. In addition, all leaf end shapes showed some increase in penumbra compared to standard divergent blocking and also had increasing penumbra width as they moved over or back from the field center line. A total of 459 treatment fields and six disease sites were examined to determine the percentage of fields potentially shaped by multileaf segments of specified length. This study showed 93% of the fields had lengths of 30 cm or less and 99% had widths of 25 cm or less. A study conducted to determine the required leaf velocity to shape various target volume configurations during complete rotation (at 1 RPM) showed that a leaf speed of at least 1.5 cm/sec at isocenter is needed for dynamic conformal treatment.

Common Undiagnosed Appendicular Fractures: Assessing radiographs of suspected fractures

Family physicians working in the emergency room or assessing acutely injured patients in the office often must assess radiographs of suspected fractures. Many common fractures are difficult to diagnose with plain film radiography. This article focuses on some commonly undiagnosed fractures, with illustrations.

Ontogeny of the F8Famide-like (morphine-modulating) peptides in the central nervous system of rats

FLFQPQRF-NH2 (F8Famide; FMRFamide-like peptide; morphine-modulating peptide) is a peptide isolated from bovine brain. It has some opiate analgesia modulating effects. In an adult rat central nervous system, F8Famide-like immunoreactivity is found in high concentrations in the posterior pituitary, hypothalamus, pons, medulla, and dorsal spinal cord. By using immunohistochemistry and radioimmunoassay, we studied the development of the F8Famide-immunoreactive system in the rat central nervous system during the ontogeny. F8Famide-immoreactive fibers and terminals first appeared in the median eminence on the twentieth embryonal day. Postnatally the F8Famide-immunoreactive system developed rapidly both in the brain and spinal cord, the immunoreactive structures having an adultlike distribution by the age of 1 week. A transient increase of the F8Famide-immunoreactive material was observed during the third and fourth postnatal weeks. By the age of 4 weeks, the F8Famide-containing neuronal system was adultlike both in distribution and quantity. The results suggest that the F8Famide-like peptides may act as neurotransmitters or neuromodulators from the time of their appearance in the brain and spinal cord. The early appearance and the distribution of the F8Famide-like immunoreactivity suggest that these peptides may participate, in addition to nociceptive mechanisms, in the regulation of blood pressure, feeding behaviour, and endocrine functions.

Breast recurrence following conservative surgery and radiation: patterns of failure, prognosis, and pathologic findings from mastectomy specimens with implications for treatment

Between 1978 and 1986, 1030 women with clinical Stage I or II breast cancer underwent excisional biopsy, axillary dissection (948 patients), and definitive irradiation. Sixty-five patients developed a recurrence in the treated breast, 9 of which were associated with simultaneous (8) or antecedent (1) distant metastases. Detection was by mammography alone in 29%, physical exam alone in 50%, and both in 21%. The median interval to recurrence was 34 months. Overall, 65% of the recurrences were in the vicinity of the original tumor; however, as the interval to recurrence increased, the percentage of operable recurrences in a separate quadrant increased. For those recurring after 5 years, 54% were in a separate quadrant. Ninety-five percent of the recurrences unassociated with distant metastases were operable and pathology revealed non-invasive cancer only in 10%. Fifty-two patients underwent salvage mastectomy. Thirteen patients had no residual tumor following excisional biopsy at the time of mastectomy. None of the following factors were predictive for no residual tumor: initial age, method of detection, interval to recurrence, location of recurrence, or histology. Local-regional control following mastectomy was 95%. The 5-year actuarial overall and disease-free survivals for salvage mastectomy patients were 84% and 59%, respectively. The only significant prognostic factor for survival was the initial clinical tumor size, which was related to the extent of the recurrence. Based on the inability to identify factors which would predict for a localized recurrence pathologically, we recommend mastectomy as the preferred surgical treatment for an isolated breast recurrence. Adjuvant chemotherapy may be beneficial in patients with an unfavorable prognosis.

The results of radiotherapy for orbital pseudotumor

Between January 1982 and March 1987, 23 patients (26 orbits) were treated for orbital pseudotumor with radiation therapy at the Department of Radiation Oncology, Hospital of the University of Pennsylvania. The patients were referred for clinical relapse after steroid taper in 70%, no response to steroids in 17%, and no steroid treatment (refused or contraindicated) in 13%. Presenting symptoms/signs included soft tissue swelling in 92% of orbits, pain in 92%, proptosis in 85%, and extraocular muscle dysfunction or ptosis in 69%. Decreased visual acuity was seen in only 19% of orbits. Biopsy was performed in nine patients. Treatment consisted of 2000 cGy in 2 weeks in 10 fractions for all patients. Median follow-up was 41 months, with a mean of 53 months, and a range of 21-92 months. Complete response was documented in 87% of orbits with soft tissue swelling, 82% with proptosis, 78% with extraocular muscle dysfunction, and 75% with pain. Of the five patients with visual acuity defects, three experienced complete recovery. There was no difference in complete response in patients biopsied versus those not biopsied. Overall, 17 orbits have remained in complete orbital response with no further steroid requirement (66%). Three orbits suffered local relapse at some point following radiation therapy and were retreated with steroids. These three orbits had durable local control off steroids at last follow-up (11%). Therefore, 77% of orbits attained durable local control and were steroid independent with radiation therapy alone or radiation therapy followed by steroids for relapse. Only one patient developed systemic lymphoma with follow-up. No pretreatment clinical factor reached statistical significance with respect to prognosis following radiation therapy at the less than or equal to .05 level. There were no significant acute or chronic side effects secondary to treatment. Steroids should continue to be first line treatment for orbital pseudotumor, but radiation therapy has a well-defined role in cases of steroid failure or in patients unable to tolerate steroid therapy.

Hydroxyapatite pseudopodagra. A syndrome of young women

Six women with acute calcific periarthritis of the first metatarsophalangeal joint (hydroxyapatite pseudopodagra) are described, and 10 previously reported cases (8 female patients and 2 male patients) are reviewed. The onset was characterized by acute pain, swelling, erythema, tenderness, and limitation of movement of the first metatarsophalangeal joint, symptoms indistinguishable from those of gouty podagra, which is associated with transient amorphous calcific deposits in the vicinity of the joint. Based on these results it appears that hydroxyapatite pseudopodagra is a disorder that predominantly affects premenopausal women.

Skeletal lymphoma

The records of forty-two patients with lymphoma of bone [.11 with Hodgkin disease (HD), 31 with non-Hodgkin lymphoma (NHL)] were retrospectively reviewed to correlate histologic type with sites of osseous involvement, radiographic patterns of bone destruction, and prognosis. The vertebral column was the most frequent site of axial involvement and the femur was the commonest site overall. In HD, the most frequent radiographic pattern was vertebral sclerosis, while periosteal reaction was noted in two focal femoral lesions and hypertrophic pulmonary osteoarthropathy in one patient. In NHL, permeative destruction predominated, while unusual layered periosteal reaction and eccentric cortical destruction were each seen in two patients. Radiographic patterns of bone involvement alone cannot be used to predict histologic type or prognosis. Staging remains the most important prognostic indicator. For skeletal lymphoma, instead of the traditional Ann Arbor Staging System, we prefer the more specific Mayo Staging System which relates the temporal appearance of osseous disease to nodal or soft-tissue disease or both.

Crystal-associated arthropathies

A wide variety of crystals have been described in association with articular disease, and previous investigations have shown a well-defined role for crystals in the pathogenesis of self-limited attacks of acute arthritis. Crystals have also been linked to chronic joint disease, but the relationship between the two is controversial. Diagnostic imaging is important in the assessment of arthropathies, particularly because it provides information about gross pathologic changes that cannot be readily determined by other methods, especially in early disease. Therefore, clinical studies correlating diagnostic imaging with laboratory and histologic findings may ultimately help to elucidate the true relationship between crystals and chronic joint disease.

Radiographic definition of the dorsal and palmar edges of the distal radius

The dorsal and palmar edges of the distal radius, as well as the concavity of the articular surface were labeled with wire and radiographs taken from neutral to 30 degrees of added dorsal tilt. The dorsal edge was identified as the structure that protrudes distally in neutral. The palmar edge was found to overlap with the sclerotic subchondral bone of the radius in neutral. With increasing dorsal tilt the profile of the palmar edge appeared as it protruded distal to the sclerotic subchondral line of the radius. The profile of the palmar edge could be distinguished from that of the dorsal edge on the anteroposterior view. The wire, which was placed midway between the dorsal and palmar edges and the concavity of the articular surface corresponded to the prominent sclerotic subchondral bone line of the distal radius. This did not change in position with increasing dorsal tilt. This clarification of the radiologic anatomy is helpful in extending the use of the anteroposterior radiograph for the interpretation of fractures and malunions of the distal radius.

Apparent changes in the alignment of the femoral component in hip arthroplasties associated with limb positioning

Three femoral components (one cemented and one uncemented straight-stem Muller and one uncemented Anatomic Medullary Locking) were placed into cadaveric or commercially available plastic femora to establish that rotation of the femur can simulate changes in femoral component alignment on the anteroposterior radiograph. The change in alignment is governed by the position of the prosthesis within the femoral canal. If the stem of the prosthesis is positioned posteriorly in the canal, external rotation simulates valgus; internal rotation results in a varus orientation. If the prosthetic stem is located anteriorly in the canal, the reverse is true. This effect was noted in all specimens for values as small as 20 degrees of rotation. Because a change in the position of a prosthesis may signify loosening, it is recommended that standardized positioning techniques be used for radiographic analysis of total hip arthroplasties.

The bent screw: a sign of postoperative recurrent dislocation

Recurrent dislocation is a recognized complication following surgical treatment of prior dislocation, especially in the shoulder. Postoperative deformity of the surgical hardware should alert one to the possibility of this complication. I report two patients in whom bending of the internal fixation screws confirmed the clinical suspicion of recurrent postoperative dislocation.

Amyloidosis in subcutaneous heroin abusers ("skin poppers' amyloidosis")

Systemic amyloidosis has recently emerged as a major cause of nephropathy among heroin abusers in New York City. Although focal glomerulosclerosis is typically seen in intravenous drug abusers who present with the nephrotic syndrome, those who escape this complication are at risk for the later development of amyloidosis related to their use of the subcutaneous route. Twenty such addicts identified between 1981 and 1984 are described. Patients typically present with chronic suppurative skin infections, edema, the nephrotic syndrome, benign urinary sediment, and normal-sized or enlarged kidneys. Tubular dysfunction, particularly renal tubular acidosis and diabetes insipidus, is frequent. Progression of renal insufficiency is characteristically rapid. Prolonged survival of heroin abusers and exhaustion of intravenous access requiring recourse to the subcutaneous route underlie the occurrence of amyloidosis in the addict population. Chronic suppurative skin infection consequent to repeated subcutaneous injection appears to be the underlying cause.

Irreducible dislocation of distal radial ulnar joint

Volar dislocations of the distal radioulnar joint are often missed initially. Late closed reduction of this joint is generally unsuccessful. Even acute reductions of the distal radioulnar joint is often incomplete or unsuccessful. This is not the case for dorsal dislocations. Obstruction to reduction may be due to the contracted volar soft tissues in late cases or to the dynamic pull of the pronator quadratus acutely. A previously unrecognized cause for difficulty in reduction is the torn triangular fibrocartilaginous complex (TFCC). When the tear occurs at its dorsal insertion on the radius, leaving the TFCC attached to the volar radius and to the ulna, it may block the reduction of the ulnar head into the sigmoid notch. Open reduction is required in such cases with repair of the TFCC.

Fracture of the ulnar sesamoid of the metacarpophalangeal joint of the thumb--an arthrographic study

We report a case of fracture of the ulnar sesamoid of the metacarpophalangeal joint of the thumb. The role of arthrography and stress X-rays in delineating the pathological anatomy of this injury is discussed.

Tibio-talar slant in Down syndrome

The presence of tibio-talar slant is reported in an adult patient with Down syndrome. No previous description of this deformity in connection with Down syndrome has been found.

MR imaging of the normal knee

The knees of 11 volunteers were examined by magnetic resonance (MR) imaging. The imaging was done with a 0.15 T resistive magnet using spin-echo pulse sequences. Normal anatomy was well displayed. The visualized structures included the menisci, cruciate ligaments, articular cartilage, cortical and cancellous bone, muscles, tendons, subcutaneous and intraarticular fat, and blood vessels. To obtain optimal visualization of the anterior cruciate ligaments, various positionings of the subjects and angulation of the imaging planes were tried. Rotation of the sagittal scanning plane away from the longitudinal axis of the body was found to be most satisfactory. The results obtained so far are very promising and demonstrate the real potential of MR imaging in the knee, which we believe lies in its ability to visualize the menisci and cruciate ligaments without use of contrast agents.

Erosive azotemic osteoarthropathy

Fifty-nine patients with end-stage renal disease undergoing long-term dialysis were studied prospectively for joint disease. Radiographic assessment allowed division of patients into 3 groups: group 1 included 12 patients with renal osteodystrophy and erosions of the metacarpophalangeal, proximal interphalangeal, distal interphalangeal, shoulder, wrist, and knee joints; group 2 had 11 patients with renal osteodystrophy without articular erosions; group 3 included 36 patients without osteodystrophy or erosions. Clinical manifestations were frequent in patients of group 1 and included episodes of arthralgias of the metacarpophalangeal, wrist, proximal interphalangeal, and knee joints. Patients of groups 1 and 2, particularly those of group 1, had a longer mean duration of dialysis and a higher mean serum alkaline phosphatase level compared with group 3 patients. The study indicates that there is a relatively high incidence (20%) of erosive arthropathy in dialysis patients. Renal osteodystrophy, more specifically, secondary hyperparathyroidism, and duration of dialysis are important factors in the development of this articular disorder.

Cross-sectional anatomy of the adult bony acetabulum

Cross-sectional cuts through the acetabulum of a cadaveric pelvis were obtained to evaluate the bony anatomy. There are six slices of 1 cm thickness which define the acetabulum. This information has been important to us primarily to assess acetabular fractures with computerized tomography.

Acetabular fracture assessment with computerized tomography

Twenty-four patients have been evaluated to demonstrate the role of computerized tomography (CT) in assessment of acetabular fractures. CT is important in defining the articular dome, intraarticular and femoral head abnormalities, associated sacroiliac damage and soft-tissue injury. The CT examination can be obtained with minimal additional discomfort to the patient.

The natural disease course of ankylosing spondylitis

One hundred fifty war veterans with ankylosing spondylitis were entered into a prospective study in 1947. In 1957, 142 were traced, and they have been reviewed periodically. Eighty-one of these patients were still alive in 1980. Information was obtained from 67 (83%) of the survivors and 51 were reexamined. This report is based on the clinical findings in these 51 patients, who have a mean disease duration of 38 years. Forty-seven (92%) were functioning well. The disease in 21 (41%) had progressed to cause severe spinal restriction. Of those, 12 had peripheral joint involvement early in their course and 9 had iritis. Seventy-four percent of the patients who had mild spinal restriction after 10 years did not progress to having more severe restriction. Eighty-one percent of the patients who had severe spinal restriction in 1980 were severely restricted within the first 10 years. Hips that were normal after 10 years of disease did not become diseased subsequently. This study suggests that a predictable pattern of ankylosing spondylitis emerges within the first 10 years of the disease.

Acetabular fracture assessment with computerized tomography

Twenty-four patients have been evaluated to demonstrate the role of computerized tomography (CT) in assessment of acetabular fractures. CT is important in defining the articular dome, intraarticular and femoral head abnormalities, associated sacroiliac damage and soft-tissue injury. The CT examination can be obtained with minimal additional discomfort to the patient.

Cross-sectional anatomy of the adult bony acetabulum

Cross-sectional cuts through the acetabulum of a cadaveric pelvis were obtained to evaluate the bony anatomy. There are six slices of 1 cm thickness which define the acetabulum. This information has been important to us primarily to assess acetabular fractures with computerized tomography.

Psychotherapy in the goldfish bowl: the role of the indigenous therapist

The therapeutic advantages and liabilities that accrue to the indigenous therapist (be he professional or paraprofessional) because of the indigenous state were explored, utilizing the five-year experience of ten indigenous therapists in Boston's North End. The current and historical proximity of therapists who live in the same neighborhood as their patients do provides both with increased access to, longitudinal knowledge about, and a blurred role concept of the other that may help or hinder the therapeutic process. Similarities in culture and values can foster alliance formation, differentiation of psychopathology, and therapeutic interventions, but also may interfere when therapy abuts culturally shared blind spots. These data are relevant to the private general psychiatrist as an indigenous therapist in non-metropolitan America.

Concordance of visual and manipulative responsiveness to novel and familiar stimuli: a function of test procedures or of prior experience?

Concordance of differential visual and manipulative responsiveness to novel stimuli at 6 months of age was found when differential attractiveness and familiarity of the stimuli were controlled. This finding corroborates the findings of an earlier study in which the same object was used as the familiarization object for all subjects. The data indicate that concordance at 6 months of age is not an artifact of the test procedure. A hypothesis suggested by the comparison of these findings with others in the literature is that the opportunity to manipulate a wide variety of objects in the natural environment may contribute to the concordance of visual and manipulative responsiveness to novel stimuli at this age.

Combination chemotherapy in murine neuroblastoma

The C1300 murine neuroblastoma system has been studied to determine its relevance as a chemotherapy model to the human disease. Studies using combination therapy revealed that BCNU/cyclophosphamide combination therapy increased the median lifespan 300% in A/J mice bearing the C1300 tumor. Cyclophosphamide/imidazole carboxamide and adriamycin/imidazole carboxamide combinations were less active, increasing median lifespans 189% and 144%, respectively. Vincristine/bleomycin were inactive even when the schedule was adjusted to coincide with the time of maximum mitoses following vincristine injections. These results suggest the BCNU/cyclophosphamide combination chemotherapy may be effective in human disease.