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67Ga imaging of nonHodgkin's lymphoma is useful for evaluating the presence of viable tumour in a residual mass after treatment. However, we have frequently seen gallium uptake in the pulmonary hila without other evidence of lymphoma. To study the significance of this finding, 79 patients with intermediate grade nonHodgkin's lymphoma were reviewed. Thirtyseven 47 had abnormal hilar gallium uptake. Twentythree of these could be fully evaluated, and only five 22 had hilar lymphoma. A pattern of bilateral, symmetric hilar uptake was seen in 19 patients, but only one had evidence of lymphoma. In 15 cases, this pattern was seen only on single photon emission computed tomography SPECT. The aetiology of this uptake remains unknown. It is not treatment related, as 12 patients had hilar gallium uptake prior to chemotherapy. Unless confirmed by other methods, hilar gallium uptake should not be attributed to lymphoma, and should not influence patient management.

Disorders of the ankle and foot are common and may pose a significant clinical problem. Acute injuries of the ankle and foot are routinely evaluated by radiographs and, if inconclusive, by magnetic resonance imaging (MRI) or computed tomagraphy (CT). In subacute or chronic injuries, where prolonged pain is unexplained, bone scintigraphy may play a significant role. The bone scan may differentiate soft tissue from bone pathology, and, being a sensitive test, it may indicated the region that needs further specific radiologic examination. It may also indicate the clinical significance of a radiologic finding. Moreover, in some clinical settings bone scintigraphy can be specific in the diagnosis. Careful attention to the technique enhances the efficiency of bone scintigraphy and SPECT allows better ivestigation of the hindfoot. The importance of ankle and foot injuries in the orthopedic practice and the better understanding of subacute and chronic injuries in athletes and in the general population has led to an increased use of specific tests such as MRI, CT, and bone scintigraphy. With improved technique and instrumentation it is no longer sufficient to indicate a focal abnormality in the ankle or foot on bone scintigraphy. More precise information about perfusion, blood pool, and specific location of a lesion can be obtained by high resolution and tomographic images. The role of bone scintigraphy in the diagnosis of such disorders will be presented with a focus on subacute traumatic injuries and related disorders, as well as its role in systemic inflammatory disorders that often involve the ankle and foot.

Purpose: We determined the level of functional damage to the kidney which inhibits further growth. Materials and Methods: Renal functional volume and percent uptake of 34 kidneys with reflux were studied by performing sequential quantitative single photon emission computerized tomography 2 times at a mean interval of 3.2 years. Results: Change in volume between the initial and repeat studies was 27.2 plus/minus 28.4 percent in all 34 kidneys. Change in volume was less than 7 percent in 8 kidneys and greater than 14 percent in 26. Receiver operating characteristic curve analysis indicated that 15.6 percent kidney uptake was associated with 75 percent sensitivity, 100 percent specificity and 94 percent accuracy in distinguishing kidneys with more than 7 percent from those with less than 7 percent change in volume. The value of kidney uptake of less than 15.6 percent was 100 percent in predicting less than 7 percent change in volume (positive predictive value) and the value of kidney uptake greater than 15.6 percent was 93 percent in predicting more than 7 percent change in volume (negative predictive value). Conclusions: Kidney uptake of less than 15.6 percent represents irreversible impairment of renal growth and indicates permanent damage in kidneys with vesicoureteral reflux.

Purpose: We evaluated whether increased differential renal function on the pentetic acid (DTPA) renogram represents elevated renal function in obstructed kidneys. Materials and Methods: In 10 patients with unilateral ureteropelvic junction obstruction and a differential function of 53 percent or greater on the DTPA renogram of the obstructed kidney we performed quantitative single photon emission computerized tomography of dimercapto-succinic acid uptake by the kidneys. Results: The absolute uptake of dimercapto-succinic acid was significantly higher in the obstructed kidneys compared to the contralateral normal kidneys (30.0 percent plus/minus 7.9 versus 25.3 percent plus/minus 8.3, t = 3.6, p less than 0.01, respectively). The elevated absolute uptake in the obstructed kidney was due to an increased functional volume compared to the contralateral normal kidneys (126.0 plus/minus 69.7 cc versus 102.3 plus/minus 59.2 cc, t = 4.4, p less than 0.01, respectively). Conclusions: The results suggest that increased relative renal function in hydronephrotic kidneys due to ureteropelvic junction obstruction is not an artifact of the DTPA renogram. It may represent a compensatory mechanism that sometimes may overcompensate resulting in a paradoxical hyperfunctioning kidney