Functional Lung Volume Research Articles

A Phase II Study of Radiotherapy and Concurrent Paclitaxel Chemotherapy in Breast-Conserving Treatment for Node-Positive Breast Cancer

Administering adjuvant chemotherapy before breast radiotherapy decreases the risk of systemic recurrence, but delays in radiotherapy could yield higher local failure. We assessed the feasibility and efficacy of placing radiotherapy earlier in the breast-conserving treatment course for lymph node-positive breast cancer. Between June 2000 and December 2004, 44 women with node-positive Stage II and III breast cancer were entered into this trial. Breast-conserving surgery and 4 cycles of doxorubicin (60 mg/m(2))/cyclophosphamide (600 mg/m(2)) were followed by 4 cycles of paclitaxel (175 mg/m(2)) delivered every 3 weeks. Radiotherapy was concurrent with the first 2 cycles of paclitaxel. The breast received 39.6 Gy in 22 fractions with a tumor bed boost of 14 Gy in 7 fractions. Regional lymphatics were included when indicated. Functional lung volume was assessed by use of the diffusing capacity for carbon monoxide as a proxy. Breast cosmesis was evaluated with the Harvard criteria. The 5-year actuarial rate of disease-free survival is 88%, and overall survival is 93%. There have been no local failures. Median follow-up is 75 months. No cases of radiation pneumonitis developed. There was no significant change in the diffusing capacity for carbon monoxide either immediately after radiotherapy (p = 0.51) or with extended follow-up (p = 0.63). Volume of irradiated breast tissue correlated with acute cosmesis, and acute Grade 3 skin toxicity developed in 2 patients. Late cosmesis was not adversely affected. Concurrent paclitaxel chemotherapy and radiotherapy after breast-conserving surgery shortened total treatment time, provided excellent local control, and was well tolerated.

Respiratory Muscle Activity Related to Flow and Lung Volume in Preterm Infants Compared With Term Infants

Infants with chronic lung disease (CLD) have a capacity to maintain functional lung volume despite alterations to their lung mechanics. We hypothesize that they achieve this by altering breathing patterns and dynamic elevation of lung volume, leading to differences in the relationship between respiratory muscle activity, flow and lung volume. Lung function and transcutaneous electromyography of the respiratory muscles (rEMG) were measured in 20 infants with CLD and in 39 healthy age-matched controls during quiet sleep. We compared coefficient of variations (CVs) of rEMG and the temporal relationship of rEMG variables, to flow and lung volume [functional residual capacity (FRC)] between these groups. The time between the start of inspiratory muscle activity and the resulting flow (tria)--in relation to respiratory cycle time--was significantly longer in infants with CLD. Although FRC had similar associations with tria and postinspiratory activity (corrected for respiratory cycle time), the CV of the diaphragmatic rEMG was lower in CLD infants (22.6 versus 31.0%, p = 0.030). The temporal relationship of rEMG to flow and FRC and the loss of adaptive variability provide additional information on coping mechanisms in infants with CLD. This technique could be used for noninvasive bedside monitoring of CLD.

Role of quantitative CT in predicting postoperative FEV1 and chronic dyspnea in patients undergoing lung resection


 
 
 Lung resection is the mainstay of treatment in patients with early stage non-small cell lung cancer. However, lung cancer patients often suffer from comorbidities and the respiratory reserve should be carefully evaluated preoperatively in order to avoid postoperative complications. Forced expiratory vol- ume in 1 second (FEV1) is considered to be an index that depicts the patient’s respiratory efficacy and its prediction has a key role in the preoperative evaluation of lung cancer patients with impaired lung function. Prediction of postoperative FEV1 is currently possible with the use of perfusion radionuclide lung scanning. Quantitative CT is the analysis of data acquired during nor- mal chest CT scan using the system’s software. By applying a dual threshold of -500 to -910 Hounsfield Units, functional lung volumes are estimated and postoperative FEV1 can be predicted by reducing the preoperative measurement by the fraction of the part to be resected. Studies have shown that preoperative predictions correlate well with the actual postoperative measurements. Additionally, quantitative CT results are in good agreement with perfusion scintigraphy predictions. Newer radiological techniques such as perfusion MRI and co-registered SPECT/CT have also been used in the preoperative evaluation with similar results. In conclusion, chest CT which is obligatory for staging, can be used for quantitative analysis of the already available data. It is technically simple, providing an accurate prediction of postoperative FEV1. Thus, quantitative CT appears to be a useful tool in the preoperative evaluation of lung cancer patients undergoing lung resection.
 
 

Not towing the allometric line: morphology and physiology of the respiratory system during postnatal development in marsupials

On the whole, marsupials are born small; the fat‐tailed dunnart produces one of the smallest and most developmentally immature newborn mammals, weighing ~13 mg. Newborn marsupials, to varying extent, rely on cutaneous gas exchange and in the extreme, e.g. the dunnart, typically do not breathe until 3–4 days postpartum. Surface area and a functional lung volume in neonatal fat‐tailed dunnarts and tammar wallabies were determined with phase‐contrast imaging using a synchrotron radiation source. Values for surface area and lung volume were both less than that expected from allometry, and remained low until the animals reached a body mass of approximately 1 gram. Interestingly, this is also the age/size where we first observe the presence of secondary septa in the lung and cutaneous gas exchange ceases. The short gestation, low birth weight and less than allometrically predicted values for lung surface area and volume (and associated implications for pulmonary diffusing capacity) and higher than predicted respiratory system resistance may all play a part in reducing ventilation and hence placing a reliance of the newborn marsupial on cutaneous respiration in the first few days of life.

DYNAMIC CHANGES IN SHUNT AND VENTILATION-PERFUSION MISMATCH FOLLOWING EXPERIMENTAL PULMONARY CONTUSION

The objective of this study was to investigate early changes in oxygenation by means of the multiple inert gas elimination technique and in coagulation by means of thromboelastography (TEG) after right-sided pulmonary contusion (PC) in swine. Anesthetized swine (group 1; n = 8) sustained a right-chest PC by a captive-bolt stunner. Multiple inert gas elimination technique, TEG, and thoracic computed tomography (CT) scans were performed before and 10, 30, 60, and 120 min after injury. Three-dimensional CT scan reconstruction enabled measurement of volumes of poorly (Vol(Poor)) and nonaerated (Vol(Non)) lung. Eight animals (group 0) were used as uninjured controls. Pulmonary contusion led to sustained tachycardia and transient hypotension. Partial pressure of arterial oxygen (PaO2) decreased from 83.9 +/- 4.2 mmHg at baseline to 51.3 +/- 2.8 mmHg 10 min after PC (P < 0.001). Vol(Poor) and Vol(Non) on the right increased significantly after PC, followed by gradual progression in injury marked by decreased Vol(Poor) and increased Vol(Non). By the multiple inert gas elimination technique, blood flow to the true shunt compartment increased from 4.4% +/- 1.0% at baseline to 21.2% +/- 4.9% 10 min after PC, P < 0.001, peaked at 33.2% +/- 7.5% 30 min after PC, P < 0.001, and remained significantly higher compared with controls. Transient increase in blood flow to low and very low ventilation-perfusion (V/Q) compartments was also seen. Clot reaction time and formation rate by TEG increased at 2 h after PC. True shunt is the major cause of hypoxemia after PC, but V/Q mismatch also contributes significantly early after injury. By CT, PC leads to significant loss of functional lung volume on the side of injury. A mild hypocoagulable state was identified 2 h after injury.

Computed tomography-defined functional lung volume after segmentectomy versus lobectomy

Lung segmentectomy reduces the extent of resection required for lobectomy, but its resulting clinical benefits remain controversial. Forty patients who underwent segmentectomy for stage I lung cancer over a 5-year period were matched to 40 patients who underwent lobectomy, using nearest available matching method with the estimated propensity score. We compared the functional volume of the ipsilateral lung to be resected, the ipsilateral lung to be preserved and the contralateral lung before, and 6 months after the operation, between the groups. Functional lung volume was defined as the lung volume representing normal attenuation (-600 to -910 Hounsfield units (HUs)) on computed tomography. We also compared the volumetric parameters to the spirometric parameters in 42 other patients, who underwent major lung resection for stage I lung cancer. We removed 11.6% of the functional lung volume by segmentectomy and 24.5% by lobectomy (P<0.001). However, the loss of the functional lung volume after segmentectomy was only 8.3% and that after lobectomy was 9.2%: this difference was not significant (P=0.7). Both the ipsilateral residual lung and the contralateral lung increased in functional volume more extensively after lobectomy than after segmentectomy. Increased postoperative functional lung volume was significantly correlated with improvement in postoperative pulmonary function (R=0.6, P<0.001). Although lung segmentectomy can reduce the extent of lung resection, it may not contribute to preserving postoperative functional lung volume because lobectomy promotes postoperative expansion of the bilateral residual lung, which compensates postoperative pulmonary functional loss to a greater extent than segmentectomy.

Role of quantitative CT in predicting postoperative FEV1 and chronic dyspnea in patients undergoing lung resection.

Lung resection is the mainstay of treatment in patients with early stage non-small cell lung cancer. However, lung cancer patients often suffer from comorbidities and the respiratory reserve should be carefully evaluated preoperatively in order to avoid postoperative complications. Forced expiratory volume in 1 second (FEV1) is considered to be an index that depicts the patient's respiratory efficacy and its prediction has a key role in the preoperative evaluation of lung cancer patients with impaired lung function. Prediction of postoperative FEV1 is currently possible with the use of perfusion radionuclide lung scanning.Quantitative CT is the analysis of data acquired during normal chest CT scan using the system's software. By applying a dual threshold of -500 to -910 Hounsfield Units, functional lung volumes are estimated and postoperative FEV1 can be predicted by reducing the preoperative measurement by the fraction of the part to be resected.Studies have shown that preoperative predictions correlate well with the actual postoperative measurements. Additionally, quantitative CT results are in good agreement with perfusion scintigraphy predictions. Newer radiological techniques such as perfusion MRI and co-registered SPECT/CT have also been used in the preoperative evaluation with similar results.In conclusion, chest CT which is obligatory for staging, can be used for quantitative analysis of the already available data. It is technically simple, providing an accurate prediction of postoperative FEV1. Thus, quantitative CT appears to be a useful tool in the preoperative evaluation of lung cancer patients undergoing lung resection.

Impact of Spect Perfusion Lung Images on Optimizing Intensity Modulated Radiotherapy Plans of Stage III Non–small Cell Lung Cancer

To explore the dose distribution difference between two intensity modulated radiotherapy (IMRT) plans with and without single photon emission CT (SPECT) lung perfusion imaging guidance. Thirty-two patients with Stage III non–small cell lung cancer (NSCLC), who were candidates for radiotherapy, were enrolled. All patients had PET-CT scans and SPECT lung perfusion scans during quiet free breathing (without breath-holds) in the same treatment position. The two types of images were accurately co-registered using methods of the 6 external markers based on Pinnacle3 treatment planning system. PET/CT images were used to define the gross target volume (GTV), and co-registered SPECT lung perfusion images were used to define the functional lung (FL) and the non-functional lung (NFL). Two IMRT plans were generated for each patient: Trial-1 and Trial-2. Trial-1 was generated without SPECT-guidance, and the main objective for Trial-1 was to minimize the mean lung dose (MLD) and the volume of the whole lung (WL) receiving 20 Gy or more. Dose-volumes obtained in this plan were used in SPECT-guided plan (Trial-2). Trial-2 was generated with SPECT-guidance. Based on dose-volume parameters of FL in Trial-1, the main objective for Trial-2 was to minimize the volume of FL receiving 20 Gy or more. Both Trial-1 and Trial-2 were prescribed to 60 Gy in 30 fractions at 90% isodose line. A Paired-Samples T Test was applied to compare the differences between the two IMRT plans, and a p value of less than 0.05 was regarded as significant. Comparing with those of Trial-1, FV5(FVX is the percentage of FL receiving X Gy or more, following the same), FV10, FV20, FV30 and the mean dose FL received (DmeanFL) decreased, and there were statistical differences (p = 0.019, 0.000, 0.000, 0.019, 0.000, respectively); WV5(WVX is the percentage of WL receiving X Gy or more, following the same), WV10 and WV20 also decreased, and there were statistical differences (p = 0.017, 0.000, 0.000, respectively); NFV50 (NFV50 is the percentage of NFL receiving 50 Gy or more) increased, and there was statistical difference (p = 0.019), too. Comparing with those of Trial-1, the dose-volume parameters of other organs at risk of Trial-2 also changed, However, there was no statistical difference (p < 0.05). IMRT plans optimized with SPECT-guidance could reduce the dose to FL significantly, while the dose to other organs at risk did not increase for NSCLC patients, which could potentially reduce lung toxicity and improve patient quality of life.

Sci-Thurs PM: Planning-07: Impact of Quantitative SPECT Corrections on SPECT-Weighted Mean Dose and Functional Lung Volume Segmentation as Applied in Functional Sparing RT Planning

Purpose: To compare functional lung volume segmentation and Single Photon Emission Computed Tomography (SPECT) weighted mean dose (SWMD) approaches used in SPECT guided treatment planning studies for patients with lung cancer. Methods and Materials: Nine lung cancer patients were consented to have a perfusion SPECT scan with 99mTc-macroaggregated albumin. Four image sets were reconstructed from each scan: one using a vendor provided ordered subsets expectation maximization (OSEM) algorithm and three quantitative SPECT reconstructions using OSEM methods with different types of attenuation and scatter corrections. SWMDs were calculated for open field with different sizes and gantry angles. Functional lung volumes were segmented in each reconstructed image using 10, 20, …, 90% of maximum SPECT intensity as a threshold. Results: Image reconstruction accuracy and thus functional lung volume segmentation are affected by several factors, such as attenuation and scatter correction, resolution recovery method and number of iterations used in reconstruction. Large differences in functional volumes (more than 50%) were found between images obtained from the four reconstructions. In contrast, the SWMD calculation produced consistent results for all SPECT reconstructions which included attenuation correction, regardless of whether or not scatter correction was used and the number of iterations. Conclusion: Functional volume segmentation is sensitive to the type of attenuation and scatter correction and number of iterations. In contrast, for images reconstructed with attenuation correction, the SWMD calculation produces consistent results and appears to be a more robust choice to be used in future studies incorporating SPECT into treatment planning.

Poster — Wed Eve—46: Quantitative Evaluation on the Accuracy of Image Registration Methods in SPECT Guided Radiation Therapy for Lung Cancer Patients

Purpose: To quantitatively evaluate the accuracy of several SPECT/CT image registration methods in recent studies and its impact on the functional lung volume segmentation in SPECT guided radiation therapy (RT) treatment planning. Methods and Materials: Five lung cancer patients were consented to have a perfusion SPECT scan with 99mTc‐macroaggregated albumin. During the scan, a low resolution CT image was acquired using the SPECT/CT scanner. This CT scan was co‐registered to the patient's planning CT scan through four rigid and deformable image registration programs (rigid registration, skin/lung control points based registration and B‐spline deformable registration). After the CT to CT co‐registration, original SPECT reconstructions were warped and co‐registered to the planning CT scan. The functional lung volumes were segmented from each deformed SPECT using 10, 20, …, 90% of maximum pixel value as a threshold. The differences in the size and contours of each functional volume were calculated. Results: Based on the evaluation of registered CT images, the result from B‐spline registration demonstrated the smallest intensity difference. Using the warped SPECT images obtained from this registration method as a reference, the smallest difference in the size and contour of functional volumes was found using rigid registration. In the point‐based registrations, a better result was found when the control points were placed on lung volume instead of body contour. Conclusion: Apply B‐spline based image registration method in SPECT‐guided RT studies was shown to be accurate. Point‐based image registration using skin markers with a standalone SPECT scanner was found least accurate.

State-of-the-art radiological techniques improve the assessment of postoperative lung function in patients with non-small cell lung cancer

Purpose The purpose of this study was to compare predictive capabilities for postoperative lung function in non-small cell lung cancer (NSCLC) patients of the state-of-the-art radiological methods including perfusion MRI, quantitative CT and SPECT/CT with that of anatomical method (i.e. qualitative CT) and traditional nuclear medicine methods such as planar imaging and SPECT. Materials and methods Perfusion MRI, CT, nuclear medicine study and measurements of %FEV 1 before and after lung resection were performed for 229 NSCLC patients (125 men and 104 women). For perfusion MRI, postoperative %FEV 1 (po%FEV 1) was predicted from semi-quantitatively assessed blood volumes within total and resected lungs, for quantitative CT, it was predicted from the functional lung volumes within total and resected lungs, for qualitative CT, from the number of segments of total and resected lungs, and for nuclear medicine studies, from uptakes within total and resected lungs. All SPECTs were automatically co-registered with CTs for preparation of SPECT/CTs. Predicted po%FEV 1s were then correlated with actual po%FEV 1s, which were measured %FEV 1s after operation. The limits of agreement were also evaluated. Results All predicted po%FEV 1s showed good correlation with actual po%FEV 1s (0.83 ≤ r ≤ 0.88, p < 0.0001). Perfusion MRI, quantitative CT and SPECT/CT demonstrated better correlation than other methods. The limits of agreement of perfusion MRI (4.4 ± 14.2%), quantitative CT (4.7 ± 14.2%) and SPECT/CT (5.1 ± 14.7%) were less than those of qualitative CT (6.0 ± 17.4%), planar imaging (5.8 ± 18.2%), and SPECT (5.5 ± 16.8%). Conclusions State-of-the-art radiological methods can predict postoperative lung function in NSCLC patients more accurately than traditional methods.

Functional image-based radiotherapy planning for non-small cell lung cancer: A simulation study

Background and purpose To investigate the incorporation of data from single-photon emission computed tomography (SPECT) or hyperpolarized helium-3 magnetic resonance imaging ( 3He-MRI) into intensity-modulated radiotherapy (IMRT) planning for non-small cell lung cancer (NSCLC). Material and methods Seven scenarios were simulated that represent cases of NSCLC with significant functional lung defects. Two independent IMRT plans were produced for each scenario; one to minimise total lung volume receiving ⩾20 Gy ( V 20), and the other to minimise only the functional lung volume receiving ⩾20 Gy ( FV 20). Dose–volume characteristics and a plan quality index related to planning target volume coverage by the 95% isodose ( V PTV95/ FV 20) were compared between anatomical and functional plans using the Wilcoxon signed ranks test. Results Compared to anatomical IMRT plans, functional planning reduced FV 20 (median 2.7%, range 0.6–3.5%, p = 0.02), and total lung V 20 (median 1.5%, 0.5–2.7%, p = 0.02), with a small reduction in mean functional lung dose (median 0.4 Gy, 0–0.7 Gy, p = 0.03). There were no significant differences in target volume coverage or organ-at-risk doses. Plan quality index was improved for functional plans (median increase 1.4, range 0–11.8, p = 0.02). Conclusions Statistically significant reductions in FV 20, V 20 and mean functional lung dose are possible when IMRT planning is supplemented by functional information derived from SPECT or 3He-MRI.

SU-FF-J-136: The Impact of Attenuation and Scatter Correction On the SPECT Guided Radiation Therapy for Lung Cancer Patients: Comparison of SPECT Weighted Mean Dose and Functional Lung Segmentation

Purpose: To investigate the impact of different types of image reconstruction and attenuation/scatter (A/S) correction on the calculation of dosimetric indices proposed to be used for Single Photon Emission Computed Tomography (SPECT) guided dose escalation in lung cancer patients. Methods and Materials: SPECT lung perfusion scans were obtained for nine lung cancer patients using 99mTc-macroaggregated albumin. Four image sets were reconstructed from each scan: one using a vendor provided ordered subsets expectation maximization (OSEM) algorithm, two quantitative SPECT reconstructions using OSEM methods with different types of A/S corrections and the fourth an OSEM reconstruction without any A/S correction. SPECT weighted mean dose (SWMD), dose function histogram, and functional lung volume have been calculated from dose distributions and regional perfusion maps. To investigate the dependence of SWMDs on gantry angle, twelve equally spaced co-planar open field radiation beams delivering the same MU were centered on the PTV. Three field sizes, 5×5, 7.5×7.5 and 10×10cm2 were considered. SWMDs were calculated for each field and reconstruction. Functional lung volumes were segmented in each reconstruction using 10, 20, …, 90% of maximum SPECT uptake as a threshold. Results: SWMDs calculated from reconstructions without A/S correction showed more than 5% average difference compared to those with corrections. With A/S corrections, more consistent SWMDs were found in all the three OSEM reconstructions (average difference ∼2%). However, a large variation was observed between segmented functional lung volumes and the V20 of these volumes in all four reconstructions. The difference between the volumes reached over 50% regardless of whether A/S correction was applied in the reconstruction. Conclusion: Functional volume segmentation is sensitive to the type of A/S correction. In contrast, SPECT weighted mean dose calculation produces more consistent results and appears to be a more robust choice for clinical outcome analysis and SPECT guided treatment planning.

Co-registered perfusion SPECT/CT: Utility for prediction of improved postoperative outcome in lung volume reduction surgery candidates

Purpose To directly compare the capabilities of perfusion scan, SPECT, co-registered SPECT/CT, and quantitatively and qualitatively assessed MDCT (i.e. quantitative CT and qualitative CT) for predicting postoperative clinical outcome for lung volume reduction surgery (LVRS) candidates. Materials and methods Twenty-five consecutive candidates (19 men and six women, age range: 42–72 years) for LVRS underwent preoperative CT and perfusion scan with SPECT. Clinical outcome of LVRS for all subjects was also assessed by determining the difference between pre- and postoperative forced expiratory volume in 1 s (FEV 1) and 6-min walking distance (6MWD). All SPECT examinations were performed on a SPECT scanner, and co-registered to thin-section CT by using commercially available software. On planar imaging, SPECT and SPECT/CT, upper versus lower zone or lobe ratios (U/Ls) were calculated from regional uptakes between upper and lower lung fields in the operated lung. On quantitatively assessed CT, U/L for all subjects was assessed from regional functional lung volumes. On qualitatively assessed CT, planar imaging, SPECT and co-registered SPECT/CT, U/Ls were assessed with a 4-point visual scoring system. To compare capabilities of predicting clinical outcome, each U/L was statistically correlated with the corresponding clinical outcome. Results Significantly fair or moderate correlations were observed between quantitatively and qualitatively assessed U/Ls obtained with all four methods and clinical outcomes (−0.60 ≤ r ≤ −0.42, p < 0.05). Conclusion Co-registered perfusion SPECT/CT has better correlation with clinical outcome in LVRS candidates than do planar imaging, SPECT or qualitatively assessed CT, and is at least as valid as quantitatively assessed CT.

Lung Volume, Breathing Pattern and Ventilation Inhomogeneity in Preterm and Term Infants

BackgroundMorphological changes in preterm infants with bronchopulmonary dysplasia (BPD) have functional consequences on lung volume, ventilation inhomogeneity and respiratory mechanics. Although some studies have shown lower lung volumes and increased ventilation inhomogeneity in BPD infants, conflicting results exist possibly due to differences in sedation and measurement techniques.Methodology/Principal FindingsWe studied 127 infants with BPD, 58 preterm infants without BPD and 239 healthy term-born infants, at a matched post-conceptional age of 44 weeks during quiet natural sleep according to ATS/ERS standards. Lung function parameters measured were functional residual capacity (FRC) and ventilation inhomogeneity by multiple breath washout as well as tidal breathing parameters. Preterm infants with BPD had only marginally lower FRC (21.4 mL/kg) than preterm infants without BPD (23.4 mL/kg) and term-born infants (22.6 mL/kg), though there was no trend with disease severity. They also showed higher respiratory rates and lower ratios of time to peak expiratory flow and expiratory time (t PTEF/t E) than healthy preterm and term controls. These changes were related to disease severity. No differences were found for ventilation inhomogeneity.ConclusionsOur results suggest that preterm infants with BPD have a high capacity to maintain functional lung volume during natural sleep. The alterations in breathing pattern with disease severity may reflect presence of adaptive mechanisms to cope with the disease process.

Chest radiograph thoracic areas and lung volumes in infants developing bronchopulmonary dysplasia

To determine whether chest radiograph (CXR) thoracic areas and lung volumes differed between infants who did and did not develop BPD and according to the severity of BPD developed. Infants developing BPD, particularly if moderate or severe, would have low CXR thoracic areas and lung volumes in the perinatal period. Prospective study. PATIENT-SUBJECT SELECTION: 53 infants with a median gestational age of 28 (range 24-32) weeks. CXR thoracic areas were calculated using a Picture Archiving and Communicating System (PACS) and lung volume assessed by measurement of functional residual capacity (FRC) in the first 72 hr after birth. BPD was diagnosed if the infants were oxygen dependent beyond 28 days, mild BPD in infants no longer oxygen dependent at 36 weeks post-menstrual age (PMA) and moderate/severe BPD in infants who required supplementary oxygen with or without respiratory support at 36 weeks PMA. Thirty two infants developed BPD, 21 had moderate/severe BPD. The median CXR thoracic areas were higher (P < 0.0001) and FRCs were lower (P < 0.0001) in the BPD compared to no BPD infants. The median CXR thoracic areas of the moderate/severe group (P < 0.001) and the mild group (P < 0.05) were greater than that of the no BPD group and the median FRC of the moderate/severe BPD group was lower than the no BPD group (<0.001) and the mild BPD group (P < 0.05). These results highlight that in the perinatal period infants developing BPD, particularly if moderate/severe, have low functional lung volumes and may have gas trapping, which likely reflects ventilation inhomogeneity.

Evaluation of Residual Functional Lung Volume on Tc-99m DTPA Aerosol Ventilation and Tc-99m MAA Perfusion Scintigraphy in Primary Ciliary Dyskinesia (Kartagener Syndrome)

Kartagener syndrome is diagnosed as sinusitis, bronchitis (bronchiectasis), and situs inversus by the clinical features. It is a subclass of primary ciliary dyskinesia (PCD) disease. A 12-year-old girl who had frequent upper and lower airway infections since birth, which was confirmed as Kartagener syndrome by HRCT imaging. We present the residual functional lung volume and mucociliary clearance findings seen on Tc-99m DTPA aerosol ventilation and Tc-99m MAA perfusion scintigraphy.

Using Lung Perfusion Spect-guidance to Protect Functional Lung with Optimizing Intensity Modulated Radiotherapy in Stage III Non-small Cell Lung Cancer Patients

To explore the possibility of using lung perfusion single photon emission computed tomography (SPECT) scans to protect functional lung with optimizing intensity modulated radiotherapy (IMRT)plan in patients with stage III non-small cell lung cancer (NSCLC). 24 patients with stage III NSCLC who were candidates for radiotherapy were enrolled. All patients had PET-CT scans and SPECT scans. The two sets of images were accurately co-registered in the ADAC treatment planning system. SPECT images were used to define a volume of functioning lung (FL) and non-functioning lung (NFL). FL refers to the region of ≥30% maximum radioactive counts and the other region was non-functional lung (NFL). Then SPECT images were classified by comparing lung perfusion deficit with area of radiological abnormality. Grade 0: no lung perfusion deficit. Grade 1: the size of radiological abnormality was similar to the area of lung perfusion deficit. Grade 2: the area of lung perfusion was bigger than that of radiological abnormality, and extends to 1 pulmonary lobe. Grade 3: the area of lung perfusion deficit exceeds 1 pulmonary lobe. The optimized IMRT objective was to minimize the dose to FL. Statistical analysis was made for the difference between the two sets of IMRT plans. All patients had lung perfusion deficits, 8 patients with grade 1 damage, 6 patients with grade 2 damage, and 10 patient with grade 3 damage. After IMRT plan optimized, both the percentage of whole lung volume received dose ≥x Gy (WLVx)and the percentage of functional lung volume received dose ≥x Gy (FLVx) were decreased. WLV10, WLV15, WLV20, WLV25, WLV30 and WLV35 decreased 9.7%, 13.8%, 17.2%, 12.9%, 9.8% and 9.8%, while FLV10, FLV15, FLV20, FLV25, LV30 and FLV35 decreased 10.8%, 14.6%, 17.3%, 14.5%, 14.5% and 10.5%. Thus the FLVx was decreased more significantly. There are significant difference in WLV10, WLV15, WLV20, WLV25, WLV30 and FLV10, FLV15, FLV20, FLV25, FLV30 between the two sets of IMRT plans (p = 0.002, 0.000, 0.000, 0.005, 0.027 and 0.002, 0.000, 0.000, 0.006, 0.010). It was a good methodology for using SPECT-guidance to protect functional lung with optimizing intensity modulated radiotherapy in stage III non-small cell lung cancer patients, potentially reducing lung toxicity.

Poster — Thurs Eve‐40: The potential of using SPECT ventilation information with IMRT for functional lung avoidance in radiotherapy of non small cell lung cancer

We have investigated the feasibility of using ventilation scans obtained from single photon emission computed tomography (SPECT) in intensity-modulated radiation therapy (IMRT) planning in lung cancer radiotherapy to avoid well functioning lung. We fused SPECT ventilation scans acquired at GE Hawkeye SPECT-CT of ten stage-III lung radiotherapy patients with planning CT in treatment planning system (Pinnacle v8.0, Philips Medical Systems). We automatically segment out 50% and 70% ventilated volumes. For each patient, we generated IMRT plans using nine equally spaced beams with and without avoiding well ventilated volume. They were compared with three beam IMRT plans with beam directions chosen to minimize the mean dose to the ventilated lung volumes, while keeping cord dose below tolerance and dose uniformity in the target. The plans generated using functional lung avoidance information reduces the doses to the functioning lung. With both IMRT avoidance plans, we could not obtain better functional avoidance or lower V-20Gy (volume receiving 20Gy or more) for total lung when the planning target volume (PTV) was surrounded by functional lung volumes. We were able to achieve better ventilated lung avoidance and lower total lung V-20Gy when the PTV is close to, but not surrounded by functioning lung volumes. For patients with the PTV that is far from 50% and 70% functional lung volumes, three-field IMRT spare the ventilated lung as well as nine-field IMRT ventilation avoidance plan, with a lower total lung V20-Gy.

SU‐GG‐J‐98: Functional Lung Preservation Using Four‐Dimensional Computed Tomography and Intensity‐Modulated Radiation Therapy for Lung Cancer

Purpose: The goal of this work is to reduce irradiation to functional lung using the four‐dimensional computed tomography (4D CT) derived images. The proposed technique is incorporated into intensity‐modulated radiation therapy (IMRT) to minimize radiation damage to healthy lung and pulmonary toxicity. Method and Materials: Fifteen patients with non‐small‐ cell lung cancer (NSCLC) were selected for this study. A BSpline deformable registration was employed to map each tissue element across the 4D CT data set to establish the correspondence of each voxel. Based on the changes in voxel intensities of each patient, functional image set was generated using pairs between expiration phase and other phases using the equalized histogram technique which equalizes the lung volume under each pixel intensity bin. All functional images were imported into the treatment planning system. The highly functional lung volumes formed by the percentile functional volumes were chosen to be the regions of interest (ROIs) for avoidance in IMRT treatment planning. Two IMRT plans with (fIMRT) and without (aIMRT) the functional image constraint were created and dose distributions including dose volume histograms (DVHs) and dose function histograms (DFHs) and other dosimetric parameters for the planning target volume (PTV) and critical structures in both plans were computed and compared. Results: Compared to aIMRT, the mean dose in fIMRT at 90 and 50 percentile levels were reduced by 2.5 Gy and 4.3 Gy, respectively. The mean reductions in the percentage of irradiated volume of 5 Gy (V5) and 20 Gy (V20) were significantly reduced from that of fIMRT. Conclusion: The dynamic functional images derived from 4D CT was used to guide IMRT planning and it was shown to be effective in preserving normal lung function for NSCLC cancer patients.